1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * INET		An implementation of the TCP/IP protocol suite for the LINUX
4  *		operating system.  INET is implemented using the  BSD Socket
5  *		interface as the means of communication with the user level.
6  *
7  *		The User Datagram Protocol (UDP).
8  *
9  * Authors:	Ross Biro
10  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11  *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
12  *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
13  *		Hirokazu Takahashi, <taka@valinux.co.jp>
14  *
15  * Fixes:
16  *		Alan Cox	:	verify_area() calls
17  *		Alan Cox	: 	stopped close while in use off icmp
18  *					messages. Not a fix but a botch that
19  *					for udp at least is 'valid'.
20  *		Alan Cox	:	Fixed icmp handling properly
21  *		Alan Cox	: 	Correct error for oversized datagrams
22  *		Alan Cox	:	Tidied select() semantics.
23  *		Alan Cox	:	udp_err() fixed properly, also now
24  *					select and read wake correctly on errors
25  *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
26  *		Alan Cox	:	UDP can count its memory
27  *		Alan Cox	:	send to an unknown connection causes
28  *					an ECONNREFUSED off the icmp, but
29  *					does NOT close.
30  *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
31  *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
32  *					bug no longer crashes it.
33  *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
34  *		Alan Cox	:	Uses skb_free_datagram
35  *		Alan Cox	:	Added get/set sockopt support.
36  *		Alan Cox	:	Broadcasting without option set returns EACCES.
37  *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
38  *		Alan Cox	:	Use ip_tos and ip_ttl
39  *		Alan Cox	:	SNMP Mibs
40  *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
41  *		Matt Dillon	:	UDP length checks.
42  *		Alan Cox	:	Smarter af_inet used properly.
43  *		Alan Cox	:	Use new kernel side addressing.
44  *		Alan Cox	:	Incorrect return on truncated datagram receive.
45  *	Arnt Gulbrandsen 	:	New udp_send and stuff
46  *		Alan Cox	:	Cache last socket
47  *		Alan Cox	:	Route cache
48  *		Jon Peatfield	:	Minor efficiency fix to sendto().
49  *		Mike Shaver	:	RFC1122 checks.
50  *		Alan Cox	:	Nonblocking error fix.
51  *	Willy Konynenberg	:	Transparent proxying support.
52  *		Mike McLagan	:	Routing by source
53  *		David S. Miller	:	New socket lookup architecture.
54  *					Last socket cache retained as it
55  *					does have a high hit rate.
56  *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
57  *		Andi Kleen	:	Some cleanups, cache destination entry
58  *					for connect.
59  *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
60  *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
61  *					return ENOTCONN for unconnected sockets (POSIX)
62  *		Janos Farkas	:	don't deliver multi/broadcasts to a different
63  *					bound-to-device socket
64  *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
65  *					datagrams.
66  *	Hirokazu Takahashi	:	sendfile() on UDP works now.
67  *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
68  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
69  *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
70  *					a single port at the same time.
71  *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
72  *	James Chapman		:	Add L2TP encapsulation type.
73  */
74 
75 #define pr_fmt(fmt) "UDP: " fmt
76 
77 #include <linux/bpf-cgroup.h>
78 #include <linux/uaccess.h>
79 #include <asm/ioctls.h>
80 #include <linux/memblock.h>
81 #include <linux/highmem.h>
82 #include <linux/types.h>
83 #include <linux/fcntl.h>
84 #include <linux/module.h>
85 #include <linux/socket.h>
86 #include <linux/sockios.h>
87 #include <linux/igmp.h>
88 #include <linux/inetdevice.h>
89 #include <linux/in.h>
90 #include <linux/errno.h>
91 #include <linux/timer.h>
92 #include <linux/mm.h>
93 #include <linux/inet.h>
94 #include <linux/netdevice.h>
95 #include <linux/slab.h>
96 #include <net/tcp_states.h>
97 #include <linux/skbuff.h>
98 #include <linux/proc_fs.h>
99 #include <linux/seq_file.h>
100 #include <net/net_namespace.h>
101 #include <net/icmp.h>
102 #include <net/inet_hashtables.h>
103 #include <net/ip_tunnels.h>
104 #include <net/route.h>
105 #include <net/checksum.h>
106 #include <net/xfrm.h>
107 #include <trace/events/udp.h>
108 #include <linux/static_key.h>
109 #include <linux/btf_ids.h>
110 #include <trace/events/skb.h>
111 #include <net/busy_poll.h>
112 #include "udp_impl.h"
113 #include <net/sock_reuseport.h>
114 #include <net/addrconf.h>
115 #include <net/udp_tunnel.h>
116 #if IS_ENABLED(CONFIG_IPV6)
117 #include <net/ipv6_stubs.h>
118 #endif
119 
120 struct udp_table udp_table __read_mostly;
121 EXPORT_SYMBOL(udp_table);
122 
123 long sysctl_udp_mem[3] __read_mostly;
124 EXPORT_SYMBOL(sysctl_udp_mem);
125 
126 atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp;
127 EXPORT_SYMBOL(udp_memory_allocated);
128 DEFINE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
129 EXPORT_PER_CPU_SYMBOL_GPL(udp_memory_per_cpu_fw_alloc);
130 
131 #define MAX_UDP_PORTS 65536
132 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
133 
udp_lib_lport_inuse(struct net * net,__u16 num,const struct udp_hslot * hslot,unsigned long * bitmap,struct sock * sk,unsigned int log)134 static int udp_lib_lport_inuse(struct net *net, __u16 num,
135 			       const struct udp_hslot *hslot,
136 			       unsigned long *bitmap,
137 			       struct sock *sk, unsigned int log)
138 {
139 	struct sock *sk2;
140 	kuid_t uid = sock_i_uid(sk);
141 
142 	sk_for_each(sk2, &hslot->head) {
143 		if (net_eq(sock_net(sk2), net) &&
144 		    sk2 != sk &&
145 		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
146 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
147 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
148 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
149 		    inet_rcv_saddr_equal(sk, sk2, true)) {
150 			if (sk2->sk_reuseport && sk->sk_reuseport &&
151 			    !rcu_access_pointer(sk->sk_reuseport_cb) &&
152 			    uid_eq(uid, sock_i_uid(sk2))) {
153 				if (!bitmap)
154 					return 0;
155 			} else {
156 				if (!bitmap)
157 					return 1;
158 				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
159 					  bitmap);
160 			}
161 		}
162 	}
163 	return 0;
164 }
165 
166 /*
167  * Note: we still hold spinlock of primary hash chain, so no other writer
168  * can insert/delete a socket with local_port == num
169  */
udp_lib_lport_inuse2(struct net * net,__u16 num,struct udp_hslot * hslot2,struct sock * sk)170 static int udp_lib_lport_inuse2(struct net *net, __u16 num,
171 				struct udp_hslot *hslot2,
172 				struct sock *sk)
173 {
174 	struct sock *sk2;
175 	kuid_t uid = sock_i_uid(sk);
176 	int res = 0;
177 
178 	spin_lock(&hslot2->lock);
179 	udp_portaddr_for_each_entry(sk2, &hslot2->head) {
180 		if (net_eq(sock_net(sk2), net) &&
181 		    sk2 != sk &&
182 		    (udp_sk(sk2)->udp_port_hash == num) &&
183 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
184 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
185 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
186 		    inet_rcv_saddr_equal(sk, sk2, true)) {
187 			if (sk2->sk_reuseport && sk->sk_reuseport &&
188 			    !rcu_access_pointer(sk->sk_reuseport_cb) &&
189 			    uid_eq(uid, sock_i_uid(sk2))) {
190 				res = 0;
191 			} else {
192 				res = 1;
193 			}
194 			break;
195 		}
196 	}
197 	spin_unlock(&hslot2->lock);
198 	return res;
199 }
200 
udp_reuseport_add_sock(struct sock * sk,struct udp_hslot * hslot)201 static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot)
202 {
203 	struct net *net = sock_net(sk);
204 	kuid_t uid = sock_i_uid(sk);
205 	struct sock *sk2;
206 
207 	sk_for_each(sk2, &hslot->head) {
208 		if (net_eq(sock_net(sk2), net) &&
209 		    sk2 != sk &&
210 		    sk2->sk_family == sk->sk_family &&
211 		    ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
212 		    (udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) &&
213 		    (sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
214 		    sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
215 		    inet_rcv_saddr_equal(sk, sk2, false)) {
216 			return reuseport_add_sock(sk, sk2,
217 						  inet_rcv_saddr_any(sk));
218 		}
219 	}
220 
221 	return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
222 }
223 
224 /**
225  *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
226  *
227  *  @sk:          socket struct in question
228  *  @snum:        port number to look up
229  *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
230  *                   with NULL address
231  */
udp_lib_get_port(struct sock * sk,unsigned short snum,unsigned int hash2_nulladdr)232 int udp_lib_get_port(struct sock *sk, unsigned short snum,
233 		     unsigned int hash2_nulladdr)
234 {
235 	struct udp_table *udptable = sk->sk_prot->h.udp_table;
236 	struct udp_hslot *hslot, *hslot2;
237 	struct net *net = sock_net(sk);
238 	int error = -EADDRINUSE;
239 
240 	if (!snum) {
241 		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
242 		unsigned short first, last;
243 		int low, high, remaining;
244 		unsigned int rand;
245 
246 		inet_get_local_port_range(net, &low, &high);
247 		remaining = (high - low) + 1;
248 
249 		rand = get_random_u32();
250 		first = reciprocal_scale(rand, remaining) + low;
251 		/*
252 		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
253 		 */
254 		rand = (rand | 1) * (udptable->mask + 1);
255 		last = first + udptable->mask + 1;
256 		do {
257 			hslot = udp_hashslot(udptable, net, first);
258 			bitmap_zero(bitmap, PORTS_PER_CHAIN);
259 			spin_lock_bh(&hslot->lock);
260 			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
261 					    udptable->log);
262 
263 			snum = first;
264 			/*
265 			 * Iterate on all possible values of snum for this hash.
266 			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
267 			 * give us randomization and full range coverage.
268 			 */
269 			do {
270 				if (low <= snum && snum <= high &&
271 				    !test_bit(snum >> udptable->log, bitmap) &&
272 				    !inet_is_local_reserved_port(net, snum))
273 					goto found;
274 				snum += rand;
275 			} while (snum != first);
276 			spin_unlock_bh(&hslot->lock);
277 			cond_resched();
278 		} while (++first != last);
279 		goto fail;
280 	} else {
281 		hslot = udp_hashslot(udptable, net, snum);
282 		spin_lock_bh(&hslot->lock);
283 		if (hslot->count > 10) {
284 			int exist;
285 			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
286 
287 			slot2          &= udptable->mask;
288 			hash2_nulladdr &= udptable->mask;
289 
290 			hslot2 = udp_hashslot2(udptable, slot2);
291 			if (hslot->count < hslot2->count)
292 				goto scan_primary_hash;
293 
294 			exist = udp_lib_lport_inuse2(net, snum, hslot2, sk);
295 			if (!exist && (hash2_nulladdr != slot2)) {
296 				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
297 				exist = udp_lib_lport_inuse2(net, snum, hslot2,
298 							     sk);
299 			}
300 			if (exist)
301 				goto fail_unlock;
302 			else
303 				goto found;
304 		}
305 scan_primary_hash:
306 		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, 0))
307 			goto fail_unlock;
308 	}
309 found:
310 	inet_sk(sk)->inet_num = snum;
311 	udp_sk(sk)->udp_port_hash = snum;
312 	udp_sk(sk)->udp_portaddr_hash ^= snum;
313 	if (sk_unhashed(sk)) {
314 		if (sk->sk_reuseport &&
315 		    udp_reuseport_add_sock(sk, hslot)) {
316 			inet_sk(sk)->inet_num = 0;
317 			udp_sk(sk)->udp_port_hash = 0;
318 			udp_sk(sk)->udp_portaddr_hash ^= snum;
319 			goto fail_unlock;
320 		}
321 
322 		sk_add_node_rcu(sk, &hslot->head);
323 		hslot->count++;
324 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
325 
326 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
327 		spin_lock(&hslot2->lock);
328 		if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
329 		    sk->sk_family == AF_INET6)
330 			hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
331 					   &hslot2->head);
332 		else
333 			hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
334 					   &hslot2->head);
335 		hslot2->count++;
336 		spin_unlock(&hslot2->lock);
337 	}
338 	sock_set_flag(sk, SOCK_RCU_FREE);
339 	error = 0;
340 fail_unlock:
341 	spin_unlock_bh(&hslot->lock);
342 fail:
343 	return error;
344 }
345 EXPORT_SYMBOL(udp_lib_get_port);
346 
udp_v4_get_port(struct sock * sk,unsigned short snum)347 int udp_v4_get_port(struct sock *sk, unsigned short snum)
348 {
349 	unsigned int hash2_nulladdr =
350 		ipv4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
351 	unsigned int hash2_partial =
352 		ipv4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
353 
354 	/* precompute partial secondary hash */
355 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
356 	return udp_lib_get_port(sk, snum, hash2_nulladdr);
357 }
358 
compute_score(struct sock * sk,struct net * net,__be32 saddr,__be16 sport,__be32 daddr,unsigned short hnum,int dif,int sdif)359 static int compute_score(struct sock *sk, struct net *net,
360 			 __be32 saddr, __be16 sport,
361 			 __be32 daddr, unsigned short hnum,
362 			 int dif, int sdif)
363 {
364 	int score;
365 	struct inet_sock *inet;
366 	bool dev_match;
367 
368 	if (!net_eq(sock_net(sk), net) ||
369 	    udp_sk(sk)->udp_port_hash != hnum ||
370 	    ipv6_only_sock(sk))
371 		return -1;
372 
373 	if (sk->sk_rcv_saddr != daddr)
374 		return -1;
375 
376 	score = (sk->sk_family == PF_INET) ? 2 : 1;
377 
378 	inet = inet_sk(sk);
379 	if (inet->inet_daddr) {
380 		if (inet->inet_daddr != saddr)
381 			return -1;
382 		score += 4;
383 	}
384 
385 	if (inet->inet_dport) {
386 		if (inet->inet_dport != sport)
387 			return -1;
388 		score += 4;
389 	}
390 
391 	dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if,
392 					dif, sdif);
393 	if (!dev_match)
394 		return -1;
395 	if (sk->sk_bound_dev_if)
396 		score += 4;
397 
398 	if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
399 		score++;
400 	return score;
401 }
402 
udp_ehashfn(const struct net * net,const __be32 laddr,const __u16 lport,const __be32 faddr,const __be16 fport)403 static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
404 		       const __u16 lport, const __be32 faddr,
405 		       const __be16 fport)
406 {
407 	static u32 udp_ehash_secret __read_mostly;
408 
409 	net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
410 
411 	return __inet_ehashfn(laddr, lport, faddr, fport,
412 			      udp_ehash_secret + net_hash_mix(net));
413 }
414 
lookup_reuseport(struct net * net,struct sock * sk,struct sk_buff * skb,__be32 saddr,__be16 sport,__be32 daddr,unsigned short hnum)415 static struct sock *lookup_reuseport(struct net *net, struct sock *sk,
416 				     struct sk_buff *skb,
417 				     __be32 saddr, __be16 sport,
418 				     __be32 daddr, unsigned short hnum)
419 {
420 	struct sock *reuse_sk = NULL;
421 	u32 hash;
422 
423 	if (sk->sk_reuseport && sk->sk_state != TCP_ESTABLISHED) {
424 		hash = udp_ehashfn(net, daddr, hnum, saddr, sport);
425 		reuse_sk = reuseport_select_sock(sk, hash, skb,
426 						 sizeof(struct udphdr));
427 	}
428 	return reuse_sk;
429 }
430 
431 /* called with rcu_read_lock() */
udp4_lib_lookup2(struct net * net,__be32 saddr,__be16 sport,__be32 daddr,unsigned int hnum,int dif,int sdif,struct udp_hslot * hslot2,struct sk_buff * skb)432 static struct sock *udp4_lib_lookup2(struct net *net,
433 				     __be32 saddr, __be16 sport,
434 				     __be32 daddr, unsigned int hnum,
435 				     int dif, int sdif,
436 				     struct udp_hslot *hslot2,
437 				     struct sk_buff *skb)
438 {
439 	struct sock *sk, *result;
440 	int score, badness;
441 
442 	result = NULL;
443 	badness = 0;
444 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
445 		score = compute_score(sk, net, saddr, sport,
446 				      daddr, hnum, dif, sdif);
447 		if (score > badness) {
448 			result = lookup_reuseport(net, sk, skb,
449 						  saddr, sport, daddr, hnum);
450 			/* Fall back to scoring if group has connections */
451 			if (result && !reuseport_has_conns(sk))
452 				return result;
453 
454 			result = result ? : sk;
455 			badness = score;
456 		}
457 	}
458 	return result;
459 }
460 
udp4_lookup_run_bpf(struct net * net,struct udp_table * udptable,struct sk_buff * skb,__be32 saddr,__be16 sport,__be32 daddr,u16 hnum,const int dif)461 static struct sock *udp4_lookup_run_bpf(struct net *net,
462 					struct udp_table *udptable,
463 					struct sk_buff *skb,
464 					__be32 saddr, __be16 sport,
465 					__be32 daddr, u16 hnum, const int dif)
466 {
467 	struct sock *sk, *reuse_sk;
468 	bool no_reuseport;
469 
470 	if (udptable != &udp_table)
471 		return NULL; /* only UDP is supported */
472 
473 	no_reuseport = bpf_sk_lookup_run_v4(net, IPPROTO_UDP, saddr, sport,
474 					    daddr, hnum, dif, &sk);
475 	if (no_reuseport || IS_ERR_OR_NULL(sk))
476 		return sk;
477 
478 	reuse_sk = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
479 	if (reuse_sk)
480 		sk = reuse_sk;
481 	return sk;
482 }
483 
484 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
485  * harder than this. -DaveM
486  */
__udp4_lib_lookup(struct net * net,__be32 saddr,__be16 sport,__be32 daddr,__be16 dport,int dif,int sdif,struct udp_table * udptable,struct sk_buff * skb)487 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
488 		__be16 sport, __be32 daddr, __be16 dport, int dif,
489 		int sdif, struct udp_table *udptable, struct sk_buff *skb)
490 {
491 	unsigned short hnum = ntohs(dport);
492 	unsigned int hash2, slot2;
493 	struct udp_hslot *hslot2;
494 	struct sock *result, *sk;
495 
496 	hash2 = ipv4_portaddr_hash(net, daddr, hnum);
497 	slot2 = hash2 & udptable->mask;
498 	hslot2 = &udptable->hash2[slot2];
499 
500 	/* Lookup connected or non-wildcard socket */
501 	result = udp4_lib_lookup2(net, saddr, sport,
502 				  daddr, hnum, dif, sdif,
503 				  hslot2, skb);
504 	if (!IS_ERR_OR_NULL(result) && result->sk_state == TCP_ESTABLISHED)
505 		goto done;
506 
507 	/* Lookup redirect from BPF */
508 	if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
509 		sk = udp4_lookup_run_bpf(net, udptable, skb,
510 					 saddr, sport, daddr, hnum, dif);
511 		if (sk) {
512 			result = sk;
513 			goto done;
514 		}
515 	}
516 
517 	/* Got non-wildcard socket or error on first lookup */
518 	if (result)
519 		goto done;
520 
521 	/* Lookup wildcard sockets */
522 	hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
523 	slot2 = hash2 & udptable->mask;
524 	hslot2 = &udptable->hash2[slot2];
525 
526 	result = udp4_lib_lookup2(net, saddr, sport,
527 				  htonl(INADDR_ANY), hnum, dif, sdif,
528 				  hslot2, skb);
529 done:
530 	if (IS_ERR(result))
531 		return NULL;
532 	return result;
533 }
534 EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
535 
__udp4_lib_lookup_skb(struct sk_buff * skb,__be16 sport,__be16 dport,struct udp_table * udptable)536 static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
537 						 __be16 sport, __be16 dport,
538 						 struct udp_table *udptable)
539 {
540 	const struct iphdr *iph = ip_hdr(skb);
541 
542 	return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
543 				 iph->daddr, dport, inet_iif(skb),
544 				 inet_sdif(skb), udptable, skb);
545 }
546 
udp4_lib_lookup_skb(const struct sk_buff * skb,__be16 sport,__be16 dport)547 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
548 				 __be16 sport, __be16 dport)
549 {
550 	const struct iphdr *iph = ip_hdr(skb);
551 
552 	return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
553 				 iph->daddr, dport, inet_iif(skb),
554 				 inet_sdif(skb), &udp_table, NULL);
555 }
556 
557 /* Must be called under rcu_read_lock().
558  * Does increment socket refcount.
559  */
560 #if IS_ENABLED(CONFIG_NF_TPROXY_IPV4) || IS_ENABLED(CONFIG_NF_SOCKET_IPV4)
udp4_lib_lookup(struct net * net,__be32 saddr,__be16 sport,__be32 daddr,__be16 dport,int dif)561 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
562 			     __be32 daddr, __be16 dport, int dif)
563 {
564 	struct sock *sk;
565 
566 	sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
567 			       dif, 0, &udp_table, NULL);
568 	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
569 		sk = NULL;
570 	return sk;
571 }
572 EXPORT_SYMBOL_GPL(udp4_lib_lookup);
573 #endif
574 
__udp_is_mcast_sock(struct net * net,struct sock * sk,__be16 loc_port,__be32 loc_addr,__be16 rmt_port,__be32 rmt_addr,int dif,int sdif,unsigned short hnum)575 static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
576 				       __be16 loc_port, __be32 loc_addr,
577 				       __be16 rmt_port, __be32 rmt_addr,
578 				       int dif, int sdif, unsigned short hnum)
579 {
580 	struct inet_sock *inet = inet_sk(sk);
581 
582 	if (!net_eq(sock_net(sk), net) ||
583 	    udp_sk(sk)->udp_port_hash != hnum ||
584 	    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
585 	    (inet->inet_dport != rmt_port && inet->inet_dport) ||
586 	    (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
587 	    ipv6_only_sock(sk) ||
588 	    !udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
589 		return false;
590 	if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif))
591 		return false;
592 	return true;
593 }
594 
595 DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
udp_encap_enable(void)596 void udp_encap_enable(void)
597 {
598 	static_branch_inc(&udp_encap_needed_key);
599 }
600 EXPORT_SYMBOL(udp_encap_enable);
601 
udp_encap_disable(void)602 void udp_encap_disable(void)
603 {
604 	static_branch_dec(&udp_encap_needed_key);
605 }
606 EXPORT_SYMBOL(udp_encap_disable);
607 
608 /* Handler for tunnels with arbitrary destination ports: no socket lookup, go
609  * through error handlers in encapsulations looking for a match.
610  */
__udp4_lib_err_encap_no_sk(struct sk_buff * skb,u32 info)611 static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info)
612 {
613 	int i;
614 
615 	for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
616 		int (*handler)(struct sk_buff *skb, u32 info);
617 		const struct ip_tunnel_encap_ops *encap;
618 
619 		encap = rcu_dereference(iptun_encaps[i]);
620 		if (!encap)
621 			continue;
622 		handler = encap->err_handler;
623 		if (handler && !handler(skb, info))
624 			return 0;
625 	}
626 
627 	return -ENOENT;
628 }
629 
630 /* Try to match ICMP errors to UDP tunnels by looking up a socket without
631  * reversing source and destination port: this will match tunnels that force the
632  * same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
633  * lwtunnels might actually break this assumption by being configured with
634  * different destination ports on endpoints, in this case we won't be able to
635  * trace ICMP messages back to them.
636  *
637  * If this doesn't match any socket, probe tunnels with arbitrary destination
638  * ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
639  * we've sent packets to won't necessarily match the local destination port.
640  *
641  * Then ask the tunnel implementation to match the error against a valid
642  * association.
643  *
644  * Return an error if we can't find a match, the socket if we need further
645  * processing, zero otherwise.
646  */
__udp4_lib_err_encap(struct net * net,const struct iphdr * iph,struct udphdr * uh,struct udp_table * udptable,struct sock * sk,struct sk_buff * skb,u32 info)647 static struct sock *__udp4_lib_err_encap(struct net *net,
648 					 const struct iphdr *iph,
649 					 struct udphdr *uh,
650 					 struct udp_table *udptable,
651 					 struct sock *sk,
652 					 struct sk_buff *skb, u32 info)
653 {
654 	int (*lookup)(struct sock *sk, struct sk_buff *skb);
655 	int network_offset, transport_offset;
656 	struct udp_sock *up;
657 
658 	network_offset = skb_network_offset(skb);
659 	transport_offset = skb_transport_offset(skb);
660 
661 	/* Network header needs to point to the outer IPv4 header inside ICMP */
662 	skb_reset_network_header(skb);
663 
664 	/* Transport header needs to point to the UDP header */
665 	skb_set_transport_header(skb, iph->ihl << 2);
666 
667 	if (sk) {
668 		up = udp_sk(sk);
669 
670 		lookup = READ_ONCE(up->encap_err_lookup);
671 		if (lookup && lookup(sk, skb))
672 			sk = NULL;
673 
674 		goto out;
675 	}
676 
677 	sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
678 			       iph->saddr, uh->dest, skb->dev->ifindex, 0,
679 			       udptable, NULL);
680 	if (sk) {
681 		up = udp_sk(sk);
682 
683 		lookup = READ_ONCE(up->encap_err_lookup);
684 		if (!lookup || lookup(sk, skb))
685 			sk = NULL;
686 	}
687 
688 out:
689 	if (!sk)
690 		sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));
691 
692 	skb_set_transport_header(skb, transport_offset);
693 	skb_set_network_header(skb, network_offset);
694 
695 	return sk;
696 }
697 
698 /*
699  * This routine is called by the ICMP module when it gets some
700  * sort of error condition.  If err < 0 then the socket should
701  * be closed and the error returned to the user.  If err > 0
702  * it's just the icmp type << 8 | icmp code.
703  * Header points to the ip header of the error packet. We move
704  * on past this. Then (as it used to claim before adjustment)
705  * header points to the first 8 bytes of the udp header.  We need
706  * to find the appropriate port.
707  */
708 
__udp4_lib_err(struct sk_buff * skb,u32 info,struct udp_table * udptable)709 int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
710 {
711 	struct inet_sock *inet;
712 	const struct iphdr *iph = (const struct iphdr *)skb->data;
713 	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
714 	const int type = icmp_hdr(skb)->type;
715 	const int code = icmp_hdr(skb)->code;
716 	bool tunnel = false;
717 	struct sock *sk;
718 	int harderr;
719 	int err;
720 	struct net *net = dev_net(skb->dev);
721 
722 	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
723 			       iph->saddr, uh->source, skb->dev->ifindex,
724 			       inet_sdif(skb), udptable, NULL);
725 
726 	if (!sk || udp_sk(sk)->encap_type) {
727 		/* No socket for error: try tunnels before discarding */
728 		if (static_branch_unlikely(&udp_encap_needed_key)) {
729 			sk = __udp4_lib_err_encap(net, iph, uh, udptable, sk, skb,
730 						  info);
731 			if (!sk)
732 				return 0;
733 		} else
734 			sk = ERR_PTR(-ENOENT);
735 
736 		if (IS_ERR(sk)) {
737 			__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
738 			return PTR_ERR(sk);
739 		}
740 
741 		tunnel = true;
742 	}
743 
744 	err = 0;
745 	harderr = 0;
746 	inet = inet_sk(sk);
747 
748 	switch (type) {
749 	default:
750 	case ICMP_TIME_EXCEEDED:
751 		err = EHOSTUNREACH;
752 		break;
753 	case ICMP_SOURCE_QUENCH:
754 		goto out;
755 	case ICMP_PARAMETERPROB:
756 		err = EPROTO;
757 		harderr = 1;
758 		break;
759 	case ICMP_DEST_UNREACH:
760 		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
761 			ipv4_sk_update_pmtu(skb, sk, info);
762 			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
763 				err = EMSGSIZE;
764 				harderr = 1;
765 				break;
766 			}
767 			goto out;
768 		}
769 		err = EHOSTUNREACH;
770 		if (code <= NR_ICMP_UNREACH) {
771 			harderr = icmp_err_convert[code].fatal;
772 			err = icmp_err_convert[code].errno;
773 		}
774 		break;
775 	case ICMP_REDIRECT:
776 		ipv4_sk_redirect(skb, sk);
777 		goto out;
778 	}
779 
780 	/*
781 	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
782 	 *	4.1.3.3.
783 	 */
784 	if (tunnel) {
785 		/* ...not for tunnels though: we don't have a sending socket */
786 		if (udp_sk(sk)->encap_err_rcv)
787 			udp_sk(sk)->encap_err_rcv(sk, skb, iph->ihl << 2);
788 		goto out;
789 	}
790 	if (!inet->recverr) {
791 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
792 			goto out;
793 	} else
794 		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
795 
796 	sk->sk_err = err;
797 	sk_error_report(sk);
798 out:
799 	return 0;
800 }
801 
udp_err(struct sk_buff * skb,u32 info)802 int udp_err(struct sk_buff *skb, u32 info)
803 {
804 	return __udp4_lib_err(skb, info, &udp_table);
805 }
806 
807 /*
808  * Throw away all pending data and cancel the corking. Socket is locked.
809  */
udp_flush_pending_frames(struct sock * sk)810 void udp_flush_pending_frames(struct sock *sk)
811 {
812 	struct udp_sock *up = udp_sk(sk);
813 
814 	if (up->pending) {
815 		up->len = 0;
816 		up->pending = 0;
817 		ip_flush_pending_frames(sk);
818 	}
819 }
820 EXPORT_SYMBOL(udp_flush_pending_frames);
821 
822 /**
823  * 	udp4_hwcsum  -  handle outgoing HW checksumming
824  * 	@skb: 	sk_buff containing the filled-in UDP header
825  * 	        (checksum field must be zeroed out)
826  *	@src:	source IP address
827  *	@dst:	destination IP address
828  */
udp4_hwcsum(struct sk_buff * skb,__be32 src,__be32 dst)829 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
830 {
831 	struct udphdr *uh = udp_hdr(skb);
832 	int offset = skb_transport_offset(skb);
833 	int len = skb->len - offset;
834 	int hlen = len;
835 	__wsum csum = 0;
836 
837 	if (!skb_has_frag_list(skb)) {
838 		/*
839 		 * Only one fragment on the socket.
840 		 */
841 		skb->csum_start = skb_transport_header(skb) - skb->head;
842 		skb->csum_offset = offsetof(struct udphdr, check);
843 		uh->check = ~csum_tcpudp_magic(src, dst, len,
844 					       IPPROTO_UDP, 0);
845 	} else {
846 		struct sk_buff *frags;
847 
848 		/*
849 		 * HW-checksum won't work as there are two or more
850 		 * fragments on the socket so that all csums of sk_buffs
851 		 * should be together
852 		 */
853 		skb_walk_frags(skb, frags) {
854 			csum = csum_add(csum, frags->csum);
855 			hlen -= frags->len;
856 		}
857 
858 		csum = skb_checksum(skb, offset, hlen, csum);
859 		skb->ip_summed = CHECKSUM_NONE;
860 
861 		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
862 		if (uh->check == 0)
863 			uh->check = CSUM_MANGLED_0;
864 	}
865 }
866 EXPORT_SYMBOL_GPL(udp4_hwcsum);
867 
868 /* Function to set UDP checksum for an IPv4 UDP packet. This is intended
869  * for the simple case like when setting the checksum for a UDP tunnel.
870  */
udp_set_csum(bool nocheck,struct sk_buff * skb,__be32 saddr,__be32 daddr,int len)871 void udp_set_csum(bool nocheck, struct sk_buff *skb,
872 		  __be32 saddr, __be32 daddr, int len)
873 {
874 	struct udphdr *uh = udp_hdr(skb);
875 
876 	if (nocheck) {
877 		uh->check = 0;
878 	} else if (skb_is_gso(skb)) {
879 		uh->check = ~udp_v4_check(len, saddr, daddr, 0);
880 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
881 		uh->check = 0;
882 		uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb));
883 		if (uh->check == 0)
884 			uh->check = CSUM_MANGLED_0;
885 	} else {
886 		skb->ip_summed = CHECKSUM_PARTIAL;
887 		skb->csum_start = skb_transport_header(skb) - skb->head;
888 		skb->csum_offset = offsetof(struct udphdr, check);
889 		uh->check = ~udp_v4_check(len, saddr, daddr, 0);
890 	}
891 }
892 EXPORT_SYMBOL(udp_set_csum);
893 
udp_send_skb(struct sk_buff * skb,struct flowi4 * fl4,struct inet_cork * cork)894 static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
895 			struct inet_cork *cork)
896 {
897 	struct sock *sk = skb->sk;
898 	struct inet_sock *inet = inet_sk(sk);
899 	struct udphdr *uh;
900 	int err;
901 	int is_udplite = IS_UDPLITE(sk);
902 	int offset = skb_transport_offset(skb);
903 	int len = skb->len - offset;
904 	int datalen = len - sizeof(*uh);
905 	__wsum csum = 0;
906 
907 	/*
908 	 * Create a UDP header
909 	 */
910 	uh = udp_hdr(skb);
911 	uh->source = inet->inet_sport;
912 	uh->dest = fl4->fl4_dport;
913 	uh->len = htons(len);
914 	uh->check = 0;
915 
916 	if (cork->gso_size) {
917 		const int hlen = skb_network_header_len(skb) +
918 				 sizeof(struct udphdr);
919 
920 		if (hlen + cork->gso_size > cork->fragsize) {
921 			kfree_skb(skb);
922 			return -EINVAL;
923 		}
924 		if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
925 			kfree_skb(skb);
926 			return -EINVAL;
927 		}
928 		if (sk->sk_no_check_tx) {
929 			kfree_skb(skb);
930 			return -EINVAL;
931 		}
932 		if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite ||
933 		    dst_xfrm(skb_dst(skb))) {
934 			kfree_skb(skb);
935 			return -EIO;
936 		}
937 
938 		if (datalen > cork->gso_size) {
939 			skb_shinfo(skb)->gso_size = cork->gso_size;
940 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
941 			skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(datalen,
942 								 cork->gso_size);
943 		}
944 		goto csum_partial;
945 	}
946 
947 	if (is_udplite)  				 /*     UDP-Lite      */
948 		csum = udplite_csum(skb);
949 
950 	else if (sk->sk_no_check_tx) {			 /* UDP csum off */
951 
952 		skb->ip_summed = CHECKSUM_NONE;
953 		goto send;
954 
955 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
956 csum_partial:
957 
958 		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
959 		goto send;
960 
961 	} else
962 		csum = udp_csum(skb);
963 
964 	/* add protocol-dependent pseudo-header */
965 	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
966 				      sk->sk_protocol, csum);
967 	if (uh->check == 0)
968 		uh->check = CSUM_MANGLED_0;
969 
970 send:
971 	err = ip_send_skb(sock_net(sk), skb);
972 	if (err) {
973 		if (err == -ENOBUFS && !inet->recverr) {
974 			UDP_INC_STATS(sock_net(sk),
975 				      UDP_MIB_SNDBUFERRORS, is_udplite);
976 			err = 0;
977 		}
978 	} else
979 		UDP_INC_STATS(sock_net(sk),
980 			      UDP_MIB_OUTDATAGRAMS, is_udplite);
981 	return err;
982 }
983 
984 /*
985  * Push out all pending data as one UDP datagram. Socket is locked.
986  */
udp_push_pending_frames(struct sock * sk)987 int udp_push_pending_frames(struct sock *sk)
988 {
989 	struct udp_sock  *up = udp_sk(sk);
990 	struct inet_sock *inet = inet_sk(sk);
991 	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
992 	struct sk_buff *skb;
993 	int err = 0;
994 
995 	skb = ip_finish_skb(sk, fl4);
996 	if (!skb)
997 		goto out;
998 
999 	err = udp_send_skb(skb, fl4, &inet->cork.base);
1000 
1001 out:
1002 	up->len = 0;
1003 	up->pending = 0;
1004 	return err;
1005 }
1006 EXPORT_SYMBOL(udp_push_pending_frames);
1007 
__udp_cmsg_send(struct cmsghdr * cmsg,u16 * gso_size)1008 static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size)
1009 {
1010 	switch (cmsg->cmsg_type) {
1011 	case UDP_SEGMENT:
1012 		if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16)))
1013 			return -EINVAL;
1014 		*gso_size = *(__u16 *)CMSG_DATA(cmsg);
1015 		return 0;
1016 	default:
1017 		return -EINVAL;
1018 	}
1019 }
1020 
udp_cmsg_send(struct sock * sk,struct msghdr * msg,u16 * gso_size)1021 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size)
1022 {
1023 	struct cmsghdr *cmsg;
1024 	bool need_ip = false;
1025 	int err;
1026 
1027 	for_each_cmsghdr(cmsg, msg) {
1028 		if (!CMSG_OK(msg, cmsg))
1029 			return -EINVAL;
1030 
1031 		if (cmsg->cmsg_level != SOL_UDP) {
1032 			need_ip = true;
1033 			continue;
1034 		}
1035 
1036 		err = __udp_cmsg_send(cmsg, gso_size);
1037 		if (err)
1038 			return err;
1039 	}
1040 
1041 	return need_ip;
1042 }
1043 EXPORT_SYMBOL_GPL(udp_cmsg_send);
1044 
udp_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)1045 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1046 {
1047 	struct inet_sock *inet = inet_sk(sk);
1048 	struct udp_sock *up = udp_sk(sk);
1049 	DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
1050 	struct flowi4 fl4_stack;
1051 	struct flowi4 *fl4;
1052 	int ulen = len;
1053 	struct ipcm_cookie ipc;
1054 	struct rtable *rt = NULL;
1055 	int free = 0;
1056 	int connected = 0;
1057 	__be32 daddr, faddr, saddr;
1058 	__be16 dport;
1059 	u8  tos;
1060 	int err, is_udplite = IS_UDPLITE(sk);
1061 	int corkreq = READ_ONCE(up->corkflag) || msg->msg_flags&MSG_MORE;
1062 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1063 	struct sk_buff *skb;
1064 	struct ip_options_data opt_copy;
1065 
1066 	if (len > 0xFFFF)
1067 		return -EMSGSIZE;
1068 
1069 	/*
1070 	 *	Check the flags.
1071 	 */
1072 
1073 	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
1074 		return -EOPNOTSUPP;
1075 
1076 	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
1077 
1078 	fl4 = &inet->cork.fl.u.ip4;
1079 	if (up->pending) {
1080 		/*
1081 		 * There are pending frames.
1082 		 * The socket lock must be held while it's corked.
1083 		 */
1084 		lock_sock(sk);
1085 		if (likely(up->pending)) {
1086 			if (unlikely(up->pending != AF_INET)) {
1087 				release_sock(sk);
1088 				return -EINVAL;
1089 			}
1090 			goto do_append_data;
1091 		}
1092 		release_sock(sk);
1093 	}
1094 	ulen += sizeof(struct udphdr);
1095 
1096 	/*
1097 	 *	Get and verify the address.
1098 	 */
1099 	if (usin) {
1100 		if (msg->msg_namelen < sizeof(*usin))
1101 			return -EINVAL;
1102 		if (usin->sin_family != AF_INET) {
1103 			if (usin->sin_family != AF_UNSPEC)
1104 				return -EAFNOSUPPORT;
1105 		}
1106 
1107 		daddr = usin->sin_addr.s_addr;
1108 		dport = usin->sin_port;
1109 		if (dport == 0)
1110 			return -EINVAL;
1111 	} else {
1112 		if (sk->sk_state != TCP_ESTABLISHED)
1113 			return -EDESTADDRREQ;
1114 		daddr = inet->inet_daddr;
1115 		dport = inet->inet_dport;
1116 		/* Open fast path for connected socket.
1117 		   Route will not be used, if at least one option is set.
1118 		 */
1119 		connected = 1;
1120 	}
1121 
1122 	ipcm_init_sk(&ipc, inet);
1123 	ipc.gso_size = READ_ONCE(up->gso_size);
1124 
1125 	if (msg->msg_controllen) {
1126 		err = udp_cmsg_send(sk, msg, &ipc.gso_size);
1127 		if (err > 0)
1128 			err = ip_cmsg_send(sk, msg, &ipc,
1129 					   sk->sk_family == AF_INET6);
1130 		if (unlikely(err < 0)) {
1131 			kfree(ipc.opt);
1132 			return err;
1133 		}
1134 		if (ipc.opt)
1135 			free = 1;
1136 		connected = 0;
1137 	}
1138 	if (!ipc.opt) {
1139 		struct ip_options_rcu *inet_opt;
1140 
1141 		rcu_read_lock();
1142 		inet_opt = rcu_dereference(inet->inet_opt);
1143 		if (inet_opt) {
1144 			memcpy(&opt_copy, inet_opt,
1145 			       sizeof(*inet_opt) + inet_opt->opt.optlen);
1146 			ipc.opt = &opt_copy.opt;
1147 		}
1148 		rcu_read_unlock();
1149 	}
1150 
1151 	if (cgroup_bpf_enabled(CGROUP_UDP4_SENDMSG) && !connected) {
1152 		err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
1153 					    (struct sockaddr *)usin, &ipc.addr);
1154 		if (err)
1155 			goto out_free;
1156 		if (usin) {
1157 			if (usin->sin_port == 0) {
1158 				/* BPF program set invalid port. Reject it. */
1159 				err = -EINVAL;
1160 				goto out_free;
1161 			}
1162 			daddr = usin->sin_addr.s_addr;
1163 			dport = usin->sin_port;
1164 		}
1165 	}
1166 
1167 	saddr = ipc.addr;
1168 	ipc.addr = faddr = daddr;
1169 
1170 	if (ipc.opt && ipc.opt->opt.srr) {
1171 		if (!daddr) {
1172 			err = -EINVAL;
1173 			goto out_free;
1174 		}
1175 		faddr = ipc.opt->opt.faddr;
1176 		connected = 0;
1177 	}
1178 	tos = get_rttos(&ipc, inet);
1179 	if (sock_flag(sk, SOCK_LOCALROUTE) ||
1180 	    (msg->msg_flags & MSG_DONTROUTE) ||
1181 	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
1182 		tos |= RTO_ONLINK;
1183 		connected = 0;
1184 	}
1185 
1186 	if (ipv4_is_multicast(daddr)) {
1187 		if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
1188 			ipc.oif = inet->mc_index;
1189 		if (!saddr)
1190 			saddr = inet->mc_addr;
1191 		connected = 0;
1192 	} else if (!ipc.oif) {
1193 		ipc.oif = inet->uc_index;
1194 	} else if (ipv4_is_lbcast(daddr) && inet->uc_index) {
1195 		/* oif is set, packet is to local broadcast and
1196 		 * uc_index is set. oif is most likely set
1197 		 * by sk_bound_dev_if. If uc_index != oif check if the
1198 		 * oif is an L3 master and uc_index is an L3 slave.
1199 		 * If so, we want to allow the send using the uc_index.
1200 		 */
1201 		if (ipc.oif != inet->uc_index &&
1202 		    ipc.oif == l3mdev_master_ifindex_by_index(sock_net(sk),
1203 							      inet->uc_index)) {
1204 			ipc.oif = inet->uc_index;
1205 		}
1206 	}
1207 
1208 	if (connected)
1209 		rt = (struct rtable *)sk_dst_check(sk, 0);
1210 
1211 	if (!rt) {
1212 		struct net *net = sock_net(sk);
1213 		__u8 flow_flags = inet_sk_flowi_flags(sk);
1214 
1215 		fl4 = &fl4_stack;
1216 
1217 		flowi4_init_output(fl4, ipc.oif, ipc.sockc.mark, tos,
1218 				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
1219 				   flow_flags,
1220 				   faddr, saddr, dport, inet->inet_sport,
1221 				   sk->sk_uid);
1222 
1223 		security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
1224 		rt = ip_route_output_flow(net, fl4, sk);
1225 		if (IS_ERR(rt)) {
1226 			err = PTR_ERR(rt);
1227 			rt = NULL;
1228 			if (err == -ENETUNREACH)
1229 				IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1230 			goto out;
1231 		}
1232 
1233 		err = -EACCES;
1234 		if ((rt->rt_flags & RTCF_BROADCAST) &&
1235 		    !sock_flag(sk, SOCK_BROADCAST))
1236 			goto out;
1237 		if (connected)
1238 			sk_dst_set(sk, dst_clone(&rt->dst));
1239 	}
1240 
1241 	if (msg->msg_flags&MSG_CONFIRM)
1242 		goto do_confirm;
1243 back_from_confirm:
1244 
1245 	saddr = fl4->saddr;
1246 	if (!ipc.addr)
1247 		daddr = ipc.addr = fl4->daddr;
1248 
1249 	/* Lockless fast path for the non-corking case. */
1250 	if (!corkreq) {
1251 		struct inet_cork cork;
1252 
1253 		skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
1254 				  sizeof(struct udphdr), &ipc, &rt,
1255 				  &cork, msg->msg_flags);
1256 		err = PTR_ERR(skb);
1257 		if (!IS_ERR_OR_NULL(skb))
1258 			err = udp_send_skb(skb, fl4, &cork);
1259 		goto out;
1260 	}
1261 
1262 	lock_sock(sk);
1263 	if (unlikely(up->pending)) {
1264 		/* The socket is already corked while preparing it. */
1265 		/* ... which is an evident application bug. --ANK */
1266 		release_sock(sk);
1267 
1268 		net_dbg_ratelimited("socket already corked\n");
1269 		err = -EINVAL;
1270 		goto out;
1271 	}
1272 	/*
1273 	 *	Now cork the socket to pend data.
1274 	 */
1275 	fl4 = &inet->cork.fl.u.ip4;
1276 	fl4->daddr = daddr;
1277 	fl4->saddr = saddr;
1278 	fl4->fl4_dport = dport;
1279 	fl4->fl4_sport = inet->inet_sport;
1280 	up->pending = AF_INET;
1281 
1282 do_append_data:
1283 	up->len += ulen;
1284 	err = ip_append_data(sk, fl4, getfrag, msg, ulen,
1285 			     sizeof(struct udphdr), &ipc, &rt,
1286 			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1287 	if (err)
1288 		udp_flush_pending_frames(sk);
1289 	else if (!corkreq)
1290 		err = udp_push_pending_frames(sk);
1291 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1292 		up->pending = 0;
1293 	release_sock(sk);
1294 
1295 out:
1296 	ip_rt_put(rt);
1297 out_free:
1298 	if (free)
1299 		kfree(ipc.opt);
1300 	if (!err)
1301 		return len;
1302 	/*
1303 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1304 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1305 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1306 	 * things).  We could add another new stat but at least for now that
1307 	 * seems like overkill.
1308 	 */
1309 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1310 		UDP_INC_STATS(sock_net(sk),
1311 			      UDP_MIB_SNDBUFERRORS, is_udplite);
1312 	}
1313 	return err;
1314 
1315 do_confirm:
1316 	if (msg->msg_flags & MSG_PROBE)
1317 		dst_confirm_neigh(&rt->dst, &fl4->daddr);
1318 	if (!(msg->msg_flags&MSG_PROBE) || len)
1319 		goto back_from_confirm;
1320 	err = 0;
1321 	goto out;
1322 }
1323 EXPORT_SYMBOL(udp_sendmsg);
1324 
udp_sendpage(struct sock * sk,struct page * page,int offset,size_t size,int flags)1325 int udp_sendpage(struct sock *sk, struct page *page, int offset,
1326 		 size_t size, int flags)
1327 {
1328 	struct inet_sock *inet = inet_sk(sk);
1329 	struct udp_sock *up = udp_sk(sk);
1330 	int ret;
1331 
1332 	if (flags & MSG_SENDPAGE_NOTLAST)
1333 		flags |= MSG_MORE;
1334 
1335 	if (!up->pending) {
1336 		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
1337 
1338 		/* Call udp_sendmsg to specify destination address which
1339 		 * sendpage interface can't pass.
1340 		 * This will succeed only when the socket is connected.
1341 		 */
1342 		ret = udp_sendmsg(sk, &msg, 0);
1343 		if (ret < 0)
1344 			return ret;
1345 	}
1346 
1347 	lock_sock(sk);
1348 
1349 	if (unlikely(!up->pending)) {
1350 		release_sock(sk);
1351 
1352 		net_dbg_ratelimited("cork failed\n");
1353 		return -EINVAL;
1354 	}
1355 
1356 	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1357 			     page, offset, size, flags);
1358 	if (ret == -EOPNOTSUPP) {
1359 		release_sock(sk);
1360 		return sock_no_sendpage(sk->sk_socket, page, offset,
1361 					size, flags);
1362 	}
1363 	if (ret < 0) {
1364 		udp_flush_pending_frames(sk);
1365 		goto out;
1366 	}
1367 
1368 	up->len += size;
1369 	if (!(READ_ONCE(up->corkflag) || (flags&MSG_MORE)))
1370 		ret = udp_push_pending_frames(sk);
1371 	if (!ret)
1372 		ret = size;
1373 out:
1374 	release_sock(sk);
1375 	return ret;
1376 }
1377 
1378 #define UDP_SKB_IS_STATELESS 0x80000000
1379 
1380 /* all head states (dst, sk, nf conntrack) except skb extensions are
1381  * cleared by udp_rcv().
1382  *
1383  * We need to preserve secpath, if present, to eventually process
1384  * IP_CMSG_PASSSEC at recvmsg() time.
1385  *
1386  * Other extensions can be cleared.
1387  */
udp_try_make_stateless(struct sk_buff * skb)1388 static bool udp_try_make_stateless(struct sk_buff *skb)
1389 {
1390 	if (!skb_has_extensions(skb))
1391 		return true;
1392 
1393 	if (!secpath_exists(skb)) {
1394 		skb_ext_reset(skb);
1395 		return true;
1396 	}
1397 
1398 	return false;
1399 }
1400 
udp_set_dev_scratch(struct sk_buff * skb)1401 static void udp_set_dev_scratch(struct sk_buff *skb)
1402 {
1403 	struct udp_dev_scratch *scratch = udp_skb_scratch(skb);
1404 
1405 	BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long));
1406 	scratch->_tsize_state = skb->truesize;
1407 #if BITS_PER_LONG == 64
1408 	scratch->len = skb->len;
1409 	scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
1410 	scratch->is_linear = !skb_is_nonlinear(skb);
1411 #endif
1412 	if (udp_try_make_stateless(skb))
1413 		scratch->_tsize_state |= UDP_SKB_IS_STATELESS;
1414 }
1415 
udp_skb_csum_unnecessary_set(struct sk_buff * skb)1416 static void udp_skb_csum_unnecessary_set(struct sk_buff *skb)
1417 {
1418 	/* We come here after udp_lib_checksum_complete() returned 0.
1419 	 * This means that __skb_checksum_complete() might have
1420 	 * set skb->csum_valid to 1.
1421 	 * On 64bit platforms, we can set csum_unnecessary
1422 	 * to true, but only if the skb is not shared.
1423 	 */
1424 #if BITS_PER_LONG == 64
1425 	if (!skb_shared(skb))
1426 		udp_skb_scratch(skb)->csum_unnecessary = true;
1427 #endif
1428 }
1429 
udp_skb_truesize(struct sk_buff * skb)1430 static int udp_skb_truesize(struct sk_buff *skb)
1431 {
1432 	return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS;
1433 }
1434 
udp_skb_has_head_state(struct sk_buff * skb)1435 static bool udp_skb_has_head_state(struct sk_buff *skb)
1436 {
1437 	return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS);
1438 }
1439 
1440 /* fully reclaim rmem/fwd memory allocated for skb */
udp_rmem_release(struct sock * sk,int size,int partial,bool rx_queue_lock_held)1441 static void udp_rmem_release(struct sock *sk, int size, int partial,
1442 			     bool rx_queue_lock_held)
1443 {
1444 	struct udp_sock *up = udp_sk(sk);
1445 	struct sk_buff_head *sk_queue;
1446 	int amt;
1447 
1448 	if (likely(partial)) {
1449 		up->forward_deficit += size;
1450 		size = up->forward_deficit;
1451 		if (size < (sk->sk_rcvbuf >> 2) &&
1452 		    !skb_queue_empty(&up->reader_queue))
1453 			return;
1454 	} else {
1455 		size += up->forward_deficit;
1456 	}
1457 	up->forward_deficit = 0;
1458 
1459 	/* acquire the sk_receive_queue for fwd allocated memory scheduling,
1460 	 * if the called don't held it already
1461 	 */
1462 	sk_queue = &sk->sk_receive_queue;
1463 	if (!rx_queue_lock_held)
1464 		spin_lock(&sk_queue->lock);
1465 
1466 
1467 	sk->sk_forward_alloc += size;
1468 	amt = (sk->sk_forward_alloc - partial) & ~(PAGE_SIZE - 1);
1469 	sk->sk_forward_alloc -= amt;
1470 
1471 	if (amt)
1472 		__sk_mem_reduce_allocated(sk, amt >> PAGE_SHIFT);
1473 
1474 	atomic_sub(size, &sk->sk_rmem_alloc);
1475 
1476 	/* this can save us from acquiring the rx queue lock on next receive */
1477 	skb_queue_splice_tail_init(sk_queue, &up->reader_queue);
1478 
1479 	if (!rx_queue_lock_held)
1480 		spin_unlock(&sk_queue->lock);
1481 }
1482 
1483 /* Note: called with reader_queue.lock held.
1484  * Instead of using skb->truesize here, find a copy of it in skb->dev_scratch
1485  * This avoids a cache line miss while receive_queue lock is held.
1486  * Look at __udp_enqueue_schedule_skb() to find where this copy is done.
1487  */
udp_skb_destructor(struct sock * sk,struct sk_buff * skb)1488 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb)
1489 {
1490 	prefetch(&skb->data);
1491 	udp_rmem_release(sk, udp_skb_truesize(skb), 1, false);
1492 }
1493 EXPORT_SYMBOL(udp_skb_destructor);
1494 
1495 /* as above, but the caller held the rx queue lock, too */
udp_skb_dtor_locked(struct sock * sk,struct sk_buff * skb)1496 static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb)
1497 {
1498 	prefetch(&skb->data);
1499 	udp_rmem_release(sk, udp_skb_truesize(skb), 1, true);
1500 }
1501 
1502 /* Idea of busylocks is to let producers grab an extra spinlock
1503  * to relieve pressure on the receive_queue spinlock shared by consumer.
1504  * Under flood, this means that only one producer can be in line
1505  * trying to acquire the receive_queue spinlock.
1506  * These busylock can be allocated on a per cpu manner, instead of a
1507  * per socket one (that would consume a cache line per socket)
1508  */
1509 static int udp_busylocks_log __read_mostly;
1510 static spinlock_t *udp_busylocks __read_mostly;
1511 
busylock_acquire(void * ptr)1512 static spinlock_t *busylock_acquire(void *ptr)
1513 {
1514 	spinlock_t *busy;
1515 
1516 	busy = udp_busylocks + hash_ptr(ptr, udp_busylocks_log);
1517 	spin_lock(busy);
1518 	return busy;
1519 }
1520 
busylock_release(spinlock_t * busy)1521 static void busylock_release(spinlock_t *busy)
1522 {
1523 	if (busy)
1524 		spin_unlock(busy);
1525 }
1526 
__udp_enqueue_schedule_skb(struct sock * sk,struct sk_buff * skb)1527 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
1528 {
1529 	struct sk_buff_head *list = &sk->sk_receive_queue;
1530 	int rmem, delta, amt, err = -ENOMEM;
1531 	spinlock_t *busy = NULL;
1532 	int size;
1533 
1534 	/* try to avoid the costly atomic add/sub pair when the receive
1535 	 * queue is full; always allow at least a packet
1536 	 */
1537 	rmem = atomic_read(&sk->sk_rmem_alloc);
1538 	if (rmem > sk->sk_rcvbuf)
1539 		goto drop;
1540 
1541 	/* Under mem pressure, it might be helpful to help udp_recvmsg()
1542 	 * having linear skbs :
1543 	 * - Reduce memory overhead and thus increase receive queue capacity
1544 	 * - Less cache line misses at copyout() time
1545 	 * - Less work at consume_skb() (less alien page frag freeing)
1546 	 */
1547 	if (rmem > (sk->sk_rcvbuf >> 1)) {
1548 		skb_condense(skb);
1549 
1550 		busy = busylock_acquire(sk);
1551 	}
1552 	size = skb->truesize;
1553 	udp_set_dev_scratch(skb);
1554 
1555 	/* we drop only if the receive buf is full and the receive
1556 	 * queue contains some other skb
1557 	 */
1558 	rmem = atomic_add_return(size, &sk->sk_rmem_alloc);
1559 	if (rmem > (size + (unsigned int)sk->sk_rcvbuf))
1560 		goto uncharge_drop;
1561 
1562 	spin_lock(&list->lock);
1563 	if (size >= sk->sk_forward_alloc) {
1564 		amt = sk_mem_pages(size);
1565 		delta = amt << PAGE_SHIFT;
1566 		if (!__sk_mem_raise_allocated(sk, delta, amt, SK_MEM_RECV)) {
1567 			err = -ENOBUFS;
1568 			spin_unlock(&list->lock);
1569 			goto uncharge_drop;
1570 		}
1571 
1572 		sk->sk_forward_alloc += delta;
1573 	}
1574 
1575 	sk->sk_forward_alloc -= size;
1576 
1577 	/* no need to setup a destructor, we will explicitly release the
1578 	 * forward allocated memory on dequeue
1579 	 */
1580 	sock_skb_set_dropcount(sk, skb);
1581 
1582 	__skb_queue_tail(list, skb);
1583 	spin_unlock(&list->lock);
1584 
1585 	if (!sock_flag(sk, SOCK_DEAD))
1586 		sk->sk_data_ready(sk);
1587 
1588 	busylock_release(busy);
1589 	return 0;
1590 
1591 uncharge_drop:
1592 	atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
1593 
1594 drop:
1595 	atomic_inc(&sk->sk_drops);
1596 	busylock_release(busy);
1597 	return err;
1598 }
1599 EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb);
1600 
udp_destruct_common(struct sock * sk)1601 void udp_destruct_common(struct sock *sk)
1602 {
1603 	/* reclaim completely the forward allocated memory */
1604 	struct udp_sock *up = udp_sk(sk);
1605 	unsigned int total = 0;
1606 	struct sk_buff *skb;
1607 
1608 	skb_queue_splice_tail_init(&sk->sk_receive_queue, &up->reader_queue);
1609 	while ((skb = __skb_dequeue(&up->reader_queue)) != NULL) {
1610 		total += skb->truesize;
1611 		kfree_skb(skb);
1612 	}
1613 	udp_rmem_release(sk, total, 0, true);
1614 }
1615 EXPORT_SYMBOL_GPL(udp_destruct_common);
1616 
udp_destruct_sock(struct sock * sk)1617 static void udp_destruct_sock(struct sock *sk)
1618 {
1619 	udp_destruct_common(sk);
1620 	inet_sock_destruct(sk);
1621 }
1622 
udp_init_sock(struct sock * sk)1623 int udp_init_sock(struct sock *sk)
1624 {
1625 	skb_queue_head_init(&udp_sk(sk)->reader_queue);
1626 	sk->sk_destruct = udp_destruct_sock;
1627 	set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
1628 	return 0;
1629 }
1630 
skb_consume_udp(struct sock * sk,struct sk_buff * skb,int len)1631 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
1632 {
1633 	if (unlikely(READ_ONCE(sk->sk_peek_off) >= 0)) {
1634 		bool slow = lock_sock_fast(sk);
1635 
1636 		sk_peek_offset_bwd(sk, len);
1637 		unlock_sock_fast(sk, slow);
1638 	}
1639 
1640 	if (!skb_unref(skb))
1641 		return;
1642 
1643 	/* In the more common cases we cleared the head states previously,
1644 	 * see __udp_queue_rcv_skb().
1645 	 */
1646 	if (unlikely(udp_skb_has_head_state(skb)))
1647 		skb_release_head_state(skb);
1648 	__consume_stateless_skb(skb);
1649 }
1650 EXPORT_SYMBOL_GPL(skb_consume_udp);
1651 
__first_packet_length(struct sock * sk,struct sk_buff_head * rcvq,int * total)1652 static struct sk_buff *__first_packet_length(struct sock *sk,
1653 					     struct sk_buff_head *rcvq,
1654 					     int *total)
1655 {
1656 	struct sk_buff *skb;
1657 
1658 	while ((skb = skb_peek(rcvq)) != NULL) {
1659 		if (udp_lib_checksum_complete(skb)) {
1660 			__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
1661 					IS_UDPLITE(sk));
1662 			__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
1663 					IS_UDPLITE(sk));
1664 			atomic_inc(&sk->sk_drops);
1665 			__skb_unlink(skb, rcvq);
1666 			*total += skb->truesize;
1667 			kfree_skb(skb);
1668 		} else {
1669 			udp_skb_csum_unnecessary_set(skb);
1670 			break;
1671 		}
1672 	}
1673 	return skb;
1674 }
1675 
1676 /**
1677  *	first_packet_length	- return length of first packet in receive queue
1678  *	@sk: socket
1679  *
1680  *	Drops all bad checksum frames, until a valid one is found.
1681  *	Returns the length of found skb, or -1 if none is found.
1682  */
first_packet_length(struct sock * sk)1683 static int first_packet_length(struct sock *sk)
1684 {
1685 	struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
1686 	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1687 	struct sk_buff *skb;
1688 	int total = 0;
1689 	int res;
1690 
1691 	spin_lock_bh(&rcvq->lock);
1692 	skb = __first_packet_length(sk, rcvq, &total);
1693 	if (!skb && !skb_queue_empty_lockless(sk_queue)) {
1694 		spin_lock(&sk_queue->lock);
1695 		skb_queue_splice_tail_init(sk_queue, rcvq);
1696 		spin_unlock(&sk_queue->lock);
1697 
1698 		skb = __first_packet_length(sk, rcvq, &total);
1699 	}
1700 	res = skb ? skb->len : -1;
1701 	if (total)
1702 		udp_rmem_release(sk, total, 1, false);
1703 	spin_unlock_bh(&rcvq->lock);
1704 	return res;
1705 }
1706 
1707 /*
1708  *	IOCTL requests applicable to the UDP protocol
1709  */
1710 
udp_ioctl(struct sock * sk,int cmd,unsigned long arg)1711 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1712 {
1713 	switch (cmd) {
1714 	case SIOCOUTQ:
1715 	{
1716 		int amount = sk_wmem_alloc_get(sk);
1717 
1718 		return put_user(amount, (int __user *)arg);
1719 	}
1720 
1721 	case SIOCINQ:
1722 	{
1723 		int amount = max_t(int, 0, first_packet_length(sk));
1724 
1725 		return put_user(amount, (int __user *)arg);
1726 	}
1727 
1728 	default:
1729 		return -ENOIOCTLCMD;
1730 	}
1731 
1732 	return 0;
1733 }
1734 EXPORT_SYMBOL(udp_ioctl);
1735 
__skb_recv_udp(struct sock * sk,unsigned int flags,int * off,int * err)1736 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
1737 			       int *off, int *err)
1738 {
1739 	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1740 	struct sk_buff_head *queue;
1741 	struct sk_buff *last;
1742 	long timeo;
1743 	int error;
1744 
1745 	queue = &udp_sk(sk)->reader_queue;
1746 	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1747 	do {
1748 		struct sk_buff *skb;
1749 
1750 		error = sock_error(sk);
1751 		if (error)
1752 			break;
1753 
1754 		error = -EAGAIN;
1755 		do {
1756 			spin_lock_bh(&queue->lock);
1757 			skb = __skb_try_recv_from_queue(sk, queue, flags, off,
1758 							err, &last);
1759 			if (skb) {
1760 				if (!(flags & MSG_PEEK))
1761 					udp_skb_destructor(sk, skb);
1762 				spin_unlock_bh(&queue->lock);
1763 				return skb;
1764 			}
1765 
1766 			if (skb_queue_empty_lockless(sk_queue)) {
1767 				spin_unlock_bh(&queue->lock);
1768 				goto busy_check;
1769 			}
1770 
1771 			/* refill the reader queue and walk it again
1772 			 * keep both queues locked to avoid re-acquiring
1773 			 * the sk_receive_queue lock if fwd memory scheduling
1774 			 * is needed.
1775 			 */
1776 			spin_lock(&sk_queue->lock);
1777 			skb_queue_splice_tail_init(sk_queue, queue);
1778 
1779 			skb = __skb_try_recv_from_queue(sk, queue, flags, off,
1780 							err, &last);
1781 			if (skb && !(flags & MSG_PEEK))
1782 				udp_skb_dtor_locked(sk, skb);
1783 			spin_unlock(&sk_queue->lock);
1784 			spin_unlock_bh(&queue->lock);
1785 			if (skb)
1786 				return skb;
1787 
1788 busy_check:
1789 			if (!sk_can_busy_loop(sk))
1790 				break;
1791 
1792 			sk_busy_loop(sk, flags & MSG_DONTWAIT);
1793 		} while (!skb_queue_empty_lockless(sk_queue));
1794 
1795 		/* sk_queue is empty, reader_queue may contain peeked packets */
1796 	} while (timeo &&
1797 		 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
1798 					      &error, &timeo,
1799 					      (struct sk_buff *)sk_queue));
1800 
1801 	*err = error;
1802 	return NULL;
1803 }
1804 EXPORT_SYMBOL(__skb_recv_udp);
1805 
udp_read_skb(struct sock * sk,skb_read_actor_t recv_actor)1806 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
1807 {
1808 	struct sk_buff *skb;
1809 	int err, copied;
1810 
1811 try_again:
1812 	skb = skb_recv_udp(sk, MSG_DONTWAIT, &err);
1813 	if (!skb)
1814 		return err;
1815 
1816 	if (udp_lib_checksum_complete(skb)) {
1817 		int is_udplite = IS_UDPLITE(sk);
1818 		struct net *net = sock_net(sk);
1819 
1820 		__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, is_udplite);
1821 		__UDP_INC_STATS(net, UDP_MIB_INERRORS, is_udplite);
1822 		atomic_inc(&sk->sk_drops);
1823 		kfree_skb(skb);
1824 		goto try_again;
1825 	}
1826 
1827 	WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
1828 	copied = recv_actor(sk, skb);
1829 	kfree_skb(skb);
1830 
1831 	return copied;
1832 }
1833 EXPORT_SYMBOL(udp_read_skb);
1834 
1835 /*
1836  * 	This should be easy, if there is something there we
1837  * 	return it, otherwise we block.
1838  */
1839 
udp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)1840 int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
1841 		int *addr_len)
1842 {
1843 	struct inet_sock *inet = inet_sk(sk);
1844 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
1845 	struct sk_buff *skb;
1846 	unsigned int ulen, copied;
1847 	int off, err, peeking = flags & MSG_PEEK;
1848 	int is_udplite = IS_UDPLITE(sk);
1849 	bool checksum_valid = false;
1850 
1851 	if (flags & MSG_ERRQUEUE)
1852 		return ip_recv_error(sk, msg, len, addr_len);
1853 
1854 try_again:
1855 	off = sk_peek_offset(sk, flags);
1856 	skb = __skb_recv_udp(sk, flags, &off, &err);
1857 	if (!skb)
1858 		return err;
1859 
1860 	ulen = udp_skb_len(skb);
1861 	copied = len;
1862 	if (copied > ulen - off)
1863 		copied = ulen - off;
1864 	else if (copied < ulen)
1865 		msg->msg_flags |= MSG_TRUNC;
1866 
1867 	/*
1868 	 * If checksum is needed at all, try to do it while copying the
1869 	 * data.  If the data is truncated, or if we only want a partial
1870 	 * coverage checksum (UDP-Lite), do it before the copy.
1871 	 */
1872 
1873 	if (copied < ulen || peeking ||
1874 	    (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
1875 		checksum_valid = udp_skb_csum_unnecessary(skb) ||
1876 				!__udp_lib_checksum_complete(skb);
1877 		if (!checksum_valid)
1878 			goto csum_copy_err;
1879 	}
1880 
1881 	if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
1882 		if (udp_skb_is_linear(skb))
1883 			err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
1884 		else
1885 			err = skb_copy_datagram_msg(skb, off, msg, copied);
1886 	} else {
1887 		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
1888 
1889 		if (err == -EINVAL)
1890 			goto csum_copy_err;
1891 	}
1892 
1893 	if (unlikely(err)) {
1894 		if (!peeking) {
1895 			atomic_inc(&sk->sk_drops);
1896 			UDP_INC_STATS(sock_net(sk),
1897 				      UDP_MIB_INERRORS, is_udplite);
1898 		}
1899 		kfree_skb(skb);
1900 		return err;
1901 	}
1902 
1903 	if (!peeking)
1904 		UDP_INC_STATS(sock_net(sk),
1905 			      UDP_MIB_INDATAGRAMS, is_udplite);
1906 
1907 	sock_recv_cmsgs(msg, sk, skb);
1908 
1909 	/* Copy the address. */
1910 	if (sin) {
1911 		sin->sin_family = AF_INET;
1912 		sin->sin_port = udp_hdr(skb)->source;
1913 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1914 		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1915 		*addr_len = sizeof(*sin);
1916 
1917 		BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
1918 						      (struct sockaddr *)sin);
1919 	}
1920 
1921 	if (udp_sk(sk)->gro_enabled)
1922 		udp_cmsg_recv(msg, sk, skb);
1923 
1924 	if (inet->cmsg_flags)
1925 		ip_cmsg_recv_offset(msg, sk, skb, sizeof(struct udphdr), off);
1926 
1927 	err = copied;
1928 	if (flags & MSG_TRUNC)
1929 		err = ulen;
1930 
1931 	skb_consume_udp(sk, skb, peeking ? -err : err);
1932 	return err;
1933 
1934 csum_copy_err:
1935 	if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
1936 				 udp_skb_destructor)) {
1937 		UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1938 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1939 	}
1940 	kfree_skb(skb);
1941 
1942 	/* starting over for a new packet, but check if we need to yield */
1943 	cond_resched();
1944 	msg->msg_flags &= ~MSG_TRUNC;
1945 	goto try_again;
1946 }
1947 
udp_pre_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)1948 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
1949 {
1950 	/* This check is replicated from __ip4_datagram_connect() and
1951 	 * intended to prevent BPF program called below from accessing bytes
1952 	 * that are out of the bound specified by user in addr_len.
1953 	 */
1954 	if (addr_len < sizeof(struct sockaddr_in))
1955 		return -EINVAL;
1956 
1957 	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
1958 }
1959 EXPORT_SYMBOL(udp_pre_connect);
1960 
__udp_disconnect(struct sock * sk,int flags)1961 int __udp_disconnect(struct sock *sk, int flags)
1962 {
1963 	struct inet_sock *inet = inet_sk(sk);
1964 	/*
1965 	 *	1003.1g - break association.
1966 	 */
1967 
1968 	sk->sk_state = TCP_CLOSE;
1969 	inet->inet_daddr = 0;
1970 	inet->inet_dport = 0;
1971 	sock_rps_reset_rxhash(sk);
1972 	sk->sk_bound_dev_if = 0;
1973 	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) {
1974 		inet_reset_saddr(sk);
1975 		if (sk->sk_prot->rehash &&
1976 		    (sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1977 			sk->sk_prot->rehash(sk);
1978 	}
1979 
1980 	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1981 		sk->sk_prot->unhash(sk);
1982 		inet->inet_sport = 0;
1983 	}
1984 	sk_dst_reset(sk);
1985 	return 0;
1986 }
1987 EXPORT_SYMBOL(__udp_disconnect);
1988 
udp_disconnect(struct sock * sk,int flags)1989 int udp_disconnect(struct sock *sk, int flags)
1990 {
1991 	lock_sock(sk);
1992 	__udp_disconnect(sk, flags);
1993 	release_sock(sk);
1994 	return 0;
1995 }
1996 EXPORT_SYMBOL(udp_disconnect);
1997 
udp_lib_unhash(struct sock * sk)1998 void udp_lib_unhash(struct sock *sk)
1999 {
2000 	if (sk_hashed(sk)) {
2001 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
2002 		struct udp_hslot *hslot, *hslot2;
2003 
2004 		hslot  = udp_hashslot(udptable, sock_net(sk),
2005 				      udp_sk(sk)->udp_port_hash);
2006 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
2007 
2008 		spin_lock_bh(&hslot->lock);
2009 		if (rcu_access_pointer(sk->sk_reuseport_cb))
2010 			reuseport_detach_sock(sk);
2011 		if (sk_del_node_init_rcu(sk)) {
2012 			hslot->count--;
2013 			inet_sk(sk)->inet_num = 0;
2014 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
2015 
2016 			spin_lock(&hslot2->lock);
2017 			hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
2018 			hslot2->count--;
2019 			spin_unlock(&hslot2->lock);
2020 		}
2021 		spin_unlock_bh(&hslot->lock);
2022 	}
2023 }
2024 EXPORT_SYMBOL(udp_lib_unhash);
2025 
2026 /*
2027  * inet_rcv_saddr was changed, we must rehash secondary hash
2028  */
udp_lib_rehash(struct sock * sk,u16 newhash)2029 void udp_lib_rehash(struct sock *sk, u16 newhash)
2030 {
2031 	if (sk_hashed(sk)) {
2032 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
2033 		struct udp_hslot *hslot, *hslot2, *nhslot2;
2034 
2035 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
2036 		nhslot2 = udp_hashslot2(udptable, newhash);
2037 		udp_sk(sk)->udp_portaddr_hash = newhash;
2038 
2039 		if (hslot2 != nhslot2 ||
2040 		    rcu_access_pointer(sk->sk_reuseport_cb)) {
2041 			hslot = udp_hashslot(udptable, sock_net(sk),
2042 					     udp_sk(sk)->udp_port_hash);
2043 			/* we must lock primary chain too */
2044 			spin_lock_bh(&hslot->lock);
2045 			if (rcu_access_pointer(sk->sk_reuseport_cb))
2046 				reuseport_detach_sock(sk);
2047 
2048 			if (hslot2 != nhslot2) {
2049 				spin_lock(&hslot2->lock);
2050 				hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
2051 				hslot2->count--;
2052 				spin_unlock(&hslot2->lock);
2053 
2054 				spin_lock(&nhslot2->lock);
2055 				hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
2056 							 &nhslot2->head);
2057 				nhslot2->count++;
2058 				spin_unlock(&nhslot2->lock);
2059 			}
2060 
2061 			spin_unlock_bh(&hslot->lock);
2062 		}
2063 	}
2064 }
2065 EXPORT_SYMBOL(udp_lib_rehash);
2066 
udp_v4_rehash(struct sock * sk)2067 void udp_v4_rehash(struct sock *sk)
2068 {
2069 	u16 new_hash = ipv4_portaddr_hash(sock_net(sk),
2070 					  inet_sk(sk)->inet_rcv_saddr,
2071 					  inet_sk(sk)->inet_num);
2072 	udp_lib_rehash(sk, new_hash);
2073 }
2074 
__udp_queue_rcv_skb(struct sock * sk,struct sk_buff * skb)2075 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
2076 {
2077 	int rc;
2078 
2079 	if (inet_sk(sk)->inet_daddr) {
2080 		sock_rps_save_rxhash(sk, skb);
2081 		sk_mark_napi_id(sk, skb);
2082 		sk_incoming_cpu_update(sk);
2083 	} else {
2084 		sk_mark_napi_id_once(sk, skb);
2085 	}
2086 
2087 	rc = __udp_enqueue_schedule_skb(sk, skb);
2088 	if (rc < 0) {
2089 		int is_udplite = IS_UDPLITE(sk);
2090 		int drop_reason;
2091 
2092 		/* Note that an ENOMEM error is charged twice */
2093 		if (rc == -ENOMEM) {
2094 			UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
2095 					is_udplite);
2096 			drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
2097 		} else {
2098 			UDP_INC_STATS(sock_net(sk), UDP_MIB_MEMERRORS,
2099 				      is_udplite);
2100 			drop_reason = SKB_DROP_REASON_PROTO_MEM;
2101 		}
2102 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2103 		kfree_skb_reason(skb, drop_reason);
2104 		trace_udp_fail_queue_rcv_skb(rc, sk);
2105 		return -1;
2106 	}
2107 
2108 	return 0;
2109 }
2110 
2111 /* returns:
2112  *  -1: error
2113  *   0: success
2114  *  >0: "udp encap" protocol resubmission
2115  *
2116  * Note that in the success and error cases, the skb is assumed to
2117  * have either been requeued or freed.
2118  */
udp_queue_rcv_one_skb(struct sock * sk,struct sk_buff * skb)2119 static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
2120 {
2121 	int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2122 	struct udp_sock *up = udp_sk(sk);
2123 	int is_udplite = IS_UDPLITE(sk);
2124 
2125 	/*
2126 	 *	Charge it to the socket, dropping if the queue is full.
2127 	 */
2128 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2129 		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2130 		goto drop;
2131 	}
2132 	nf_reset_ct(skb);
2133 
2134 	if (static_branch_unlikely(&udp_encap_needed_key) && up->encap_type) {
2135 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
2136 
2137 		/*
2138 		 * This is an encapsulation socket so pass the skb to
2139 		 * the socket's udp_encap_rcv() hook. Otherwise, just
2140 		 * fall through and pass this up the UDP socket.
2141 		 * up->encap_rcv() returns the following value:
2142 		 * =0 if skb was successfully passed to the encap
2143 		 *    handler or was discarded by it.
2144 		 * >0 if skb should be passed on to UDP.
2145 		 * <0 if skb should be resubmitted as proto -N
2146 		 */
2147 
2148 		/* if we're overly short, let UDP handle it */
2149 		encap_rcv = READ_ONCE(up->encap_rcv);
2150 		if (encap_rcv) {
2151 			int ret;
2152 
2153 			/* Verify checksum before giving to encap */
2154 			if (udp_lib_checksum_complete(skb))
2155 				goto csum_error;
2156 
2157 			ret = encap_rcv(sk, skb);
2158 			if (ret <= 0) {
2159 				__UDP_INC_STATS(sock_net(sk),
2160 						UDP_MIB_INDATAGRAMS,
2161 						is_udplite);
2162 				return -ret;
2163 			}
2164 		}
2165 
2166 		/* FALLTHROUGH -- it's a UDP Packet */
2167 	}
2168 
2169 	/*
2170 	 * 	UDP-Lite specific tests, ignored on UDP sockets
2171 	 */
2172 	if ((up->pcflag & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
2173 
2174 		/*
2175 		 * MIB statistics other than incrementing the error count are
2176 		 * disabled for the following two types of errors: these depend
2177 		 * on the application settings, not on the functioning of the
2178 		 * protocol stack as such.
2179 		 *
2180 		 * RFC 3828 here recommends (sec 3.3): "There should also be a
2181 		 * way ... to ... at least let the receiving application block
2182 		 * delivery of packets with coverage values less than a value
2183 		 * provided by the application."
2184 		 */
2185 		if (up->pcrlen == 0) {          /* full coverage was set  */
2186 			net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
2187 					    UDP_SKB_CB(skb)->cscov, skb->len);
2188 			goto drop;
2189 		}
2190 		/* The next case involves violating the min. coverage requested
2191 		 * by the receiver. This is subtle: if receiver wants x and x is
2192 		 * greater than the buffersize/MTU then receiver will complain
2193 		 * that it wants x while sender emits packets of smaller size y.
2194 		 * Therefore the above ...()->partial_cov statement is essential.
2195 		 */
2196 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
2197 			net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
2198 					    UDP_SKB_CB(skb)->cscov, up->pcrlen);
2199 			goto drop;
2200 		}
2201 	}
2202 
2203 	prefetch(&sk->sk_rmem_alloc);
2204 	if (rcu_access_pointer(sk->sk_filter) &&
2205 	    udp_lib_checksum_complete(skb))
2206 			goto csum_error;
2207 
2208 	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) {
2209 		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2210 		goto drop;
2211 	}
2212 
2213 	udp_csum_pull_header(skb);
2214 
2215 	ipv4_pktinfo_prepare(sk, skb);
2216 	return __udp_queue_rcv_skb(sk, skb);
2217 
2218 csum_error:
2219 	drop_reason = SKB_DROP_REASON_UDP_CSUM;
2220 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
2221 drop:
2222 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2223 	atomic_inc(&sk->sk_drops);
2224 	kfree_skb_reason(skb, drop_reason);
2225 	return -1;
2226 }
2227 
udp_queue_rcv_skb(struct sock * sk,struct sk_buff * skb)2228 static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
2229 {
2230 	struct sk_buff *next, *segs;
2231 	int ret;
2232 
2233 	if (likely(!udp_unexpected_gso(sk, skb)))
2234 		return udp_queue_rcv_one_skb(sk, skb);
2235 
2236 	BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_GSO_CB_OFFSET);
2237 	__skb_push(skb, -skb_mac_offset(skb));
2238 	segs = udp_rcv_segment(sk, skb, true);
2239 	skb_list_walk_safe(segs, skb, next) {
2240 		__skb_pull(skb, skb_transport_offset(skb));
2241 
2242 		udp_post_segment_fix_csum(skb);
2243 		ret = udp_queue_rcv_one_skb(sk, skb);
2244 		if (ret > 0)
2245 			ip_protocol_deliver_rcu(dev_net(skb->dev), skb, ret);
2246 	}
2247 	return 0;
2248 }
2249 
2250 /* For TCP sockets, sk_rx_dst is protected by socket lock
2251  * For UDP, we use xchg() to guard against concurrent changes.
2252  */
udp_sk_rx_dst_set(struct sock * sk,struct dst_entry * dst)2253 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
2254 {
2255 	struct dst_entry *old;
2256 
2257 	if (dst_hold_safe(dst)) {
2258 		old = xchg((__force struct dst_entry **)&sk->sk_rx_dst, dst);
2259 		dst_release(old);
2260 		return old != dst;
2261 	}
2262 	return false;
2263 }
2264 EXPORT_SYMBOL(udp_sk_rx_dst_set);
2265 
2266 /*
2267  *	Multicasts and broadcasts go to each listener.
2268  *
2269  *	Note: called only from the BH handler context.
2270  */
__udp4_lib_mcast_deliver(struct net * net,struct sk_buff * skb,struct udphdr * uh,__be32 saddr,__be32 daddr,struct udp_table * udptable,int proto)2271 static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
2272 				    struct udphdr  *uh,
2273 				    __be32 saddr, __be32 daddr,
2274 				    struct udp_table *udptable,
2275 				    int proto)
2276 {
2277 	struct sock *sk, *first = NULL;
2278 	unsigned short hnum = ntohs(uh->dest);
2279 	struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
2280 	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
2281 	unsigned int offset = offsetof(typeof(*sk), sk_node);
2282 	int dif = skb->dev->ifindex;
2283 	int sdif = inet_sdif(skb);
2284 	struct hlist_node *node;
2285 	struct sk_buff *nskb;
2286 
2287 	if (use_hash2) {
2288 		hash2_any = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
2289 			    udptable->mask;
2290 		hash2 = ipv4_portaddr_hash(net, daddr, hnum) & udptable->mask;
2291 start_lookup:
2292 		hslot = &udptable->hash2[hash2];
2293 		offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
2294 	}
2295 
2296 	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
2297 		if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr,
2298 					 uh->source, saddr, dif, sdif, hnum))
2299 			continue;
2300 
2301 		if (!first) {
2302 			first = sk;
2303 			continue;
2304 		}
2305 		nskb = skb_clone(skb, GFP_ATOMIC);
2306 
2307 		if (unlikely(!nskb)) {
2308 			atomic_inc(&sk->sk_drops);
2309 			__UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
2310 					IS_UDPLITE(sk));
2311 			__UDP_INC_STATS(net, UDP_MIB_INERRORS,
2312 					IS_UDPLITE(sk));
2313 			continue;
2314 		}
2315 		if (udp_queue_rcv_skb(sk, nskb) > 0)
2316 			consume_skb(nskb);
2317 	}
2318 
2319 	/* Also lookup *:port if we are using hash2 and haven't done so yet. */
2320 	if (use_hash2 && hash2 != hash2_any) {
2321 		hash2 = hash2_any;
2322 		goto start_lookup;
2323 	}
2324 
2325 	if (first) {
2326 		if (udp_queue_rcv_skb(first, skb) > 0)
2327 			consume_skb(skb);
2328 	} else {
2329 		kfree_skb(skb);
2330 		__UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
2331 				proto == IPPROTO_UDPLITE);
2332 	}
2333 	return 0;
2334 }
2335 
2336 /* Initialize UDP checksum. If exited with zero value (success),
2337  * CHECKSUM_UNNECESSARY means, that no more checks are required.
2338  * Otherwise, csum completion requires checksumming packet body,
2339  * including udp header and folding it to skb->csum.
2340  */
udp4_csum_init(struct sk_buff * skb,struct udphdr * uh,int proto)2341 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
2342 				 int proto)
2343 {
2344 	int err;
2345 
2346 	UDP_SKB_CB(skb)->partial_cov = 0;
2347 	UDP_SKB_CB(skb)->cscov = skb->len;
2348 
2349 	if (proto == IPPROTO_UDPLITE) {
2350 		err = udplite_checksum_init(skb, uh);
2351 		if (err)
2352 			return err;
2353 
2354 		if (UDP_SKB_CB(skb)->partial_cov) {
2355 			skb->csum = inet_compute_pseudo(skb, proto);
2356 			return 0;
2357 		}
2358 	}
2359 
2360 	/* Note, we are only interested in != 0 or == 0, thus the
2361 	 * force to int.
2362 	 */
2363 	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
2364 							inet_compute_pseudo);
2365 	if (err)
2366 		return err;
2367 
2368 	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
2369 		/* If SW calculated the value, we know it's bad */
2370 		if (skb->csum_complete_sw)
2371 			return 1;
2372 
2373 		/* HW says the value is bad. Let's validate that.
2374 		 * skb->csum is no longer the full packet checksum,
2375 		 * so don't treat it as such.
2376 		 */
2377 		skb_checksum_complete_unset(skb);
2378 	}
2379 
2380 	return 0;
2381 }
2382 
2383 /* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
2384  * return code conversion for ip layer consumption
2385  */
udp_unicast_rcv_skb(struct sock * sk,struct sk_buff * skb,struct udphdr * uh)2386 static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
2387 			       struct udphdr *uh)
2388 {
2389 	int ret;
2390 
2391 	if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
2392 		skb_checksum_try_convert(skb, IPPROTO_UDP, inet_compute_pseudo);
2393 
2394 	ret = udp_queue_rcv_skb(sk, skb);
2395 
2396 	/* a return value > 0 means to resubmit the input, but
2397 	 * it wants the return to be -protocol, or 0
2398 	 */
2399 	if (ret > 0)
2400 		return -ret;
2401 	return 0;
2402 }
2403 
2404 /*
2405  *	All we need to do is get the socket, and then do a checksum.
2406  */
2407 
__udp4_lib_rcv(struct sk_buff * skb,struct udp_table * udptable,int proto)2408 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
2409 		   int proto)
2410 {
2411 	struct sock *sk;
2412 	struct udphdr *uh;
2413 	unsigned short ulen;
2414 	struct rtable *rt = skb_rtable(skb);
2415 	__be32 saddr, daddr;
2416 	struct net *net = dev_net(skb->dev);
2417 	bool refcounted;
2418 	int drop_reason;
2419 
2420 	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2421 
2422 	/*
2423 	 *  Validate the packet.
2424 	 */
2425 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
2426 		goto drop;		/* No space for header. */
2427 
2428 	uh   = udp_hdr(skb);
2429 	ulen = ntohs(uh->len);
2430 	saddr = ip_hdr(skb)->saddr;
2431 	daddr = ip_hdr(skb)->daddr;
2432 
2433 	if (ulen > skb->len)
2434 		goto short_packet;
2435 
2436 	if (proto == IPPROTO_UDP) {
2437 		/* UDP validates ulen. */
2438 		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
2439 			goto short_packet;
2440 		uh = udp_hdr(skb);
2441 	}
2442 
2443 	if (udp4_csum_init(skb, uh, proto))
2444 		goto csum_error;
2445 
2446 	sk = skb_steal_sock(skb, &refcounted);
2447 	if (sk) {
2448 		struct dst_entry *dst = skb_dst(skb);
2449 		int ret;
2450 
2451 		if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
2452 			udp_sk_rx_dst_set(sk, dst);
2453 
2454 		ret = udp_unicast_rcv_skb(sk, skb, uh);
2455 		if (refcounted)
2456 			sock_put(sk);
2457 		return ret;
2458 	}
2459 
2460 	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
2461 		return __udp4_lib_mcast_deliver(net, skb, uh,
2462 						saddr, daddr, udptable, proto);
2463 
2464 	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
2465 	if (sk)
2466 		return udp_unicast_rcv_skb(sk, skb, uh);
2467 
2468 	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2469 		goto drop;
2470 	nf_reset_ct(skb);
2471 
2472 	/* No socket. Drop packet silently, if checksum is wrong */
2473 	if (udp_lib_checksum_complete(skb))
2474 		goto csum_error;
2475 
2476 	drop_reason = SKB_DROP_REASON_NO_SOCKET;
2477 	__UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
2478 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
2479 
2480 	/*
2481 	 * Hmm.  We got an UDP packet to a port to which we
2482 	 * don't wanna listen.  Ignore it.
2483 	 */
2484 	kfree_skb_reason(skb, drop_reason);
2485 	return 0;
2486 
2487 short_packet:
2488 	drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2489 	net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
2490 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
2491 			    &saddr, ntohs(uh->source),
2492 			    ulen, skb->len,
2493 			    &daddr, ntohs(uh->dest));
2494 	goto drop;
2495 
2496 csum_error:
2497 	/*
2498 	 * RFC1122: OK.  Discards the bad packet silently (as far as
2499 	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
2500 	 */
2501 	drop_reason = SKB_DROP_REASON_UDP_CSUM;
2502 	net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
2503 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
2504 			    &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
2505 			    ulen);
2506 	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
2507 drop:
2508 	__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
2509 	kfree_skb_reason(skb, drop_reason);
2510 	return 0;
2511 }
2512 
2513 /* We can only early demux multicast if there is a single matching socket.
2514  * If more than one socket found returns NULL
2515  */
__udp4_lib_mcast_demux_lookup(struct net * net,__be16 loc_port,__be32 loc_addr,__be16 rmt_port,__be32 rmt_addr,int dif,int sdif)2516 static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
2517 						  __be16 loc_port, __be32 loc_addr,
2518 						  __be16 rmt_port, __be32 rmt_addr,
2519 						  int dif, int sdif)
2520 {
2521 	unsigned short hnum = ntohs(loc_port);
2522 	struct sock *sk, *result;
2523 	struct udp_hslot *hslot;
2524 	unsigned int slot;
2525 
2526 	slot = udp_hashfn(net, hnum, udp_table.mask);
2527 	hslot = &udp_table.hash[slot];
2528 
2529 	/* Do not bother scanning a too big list */
2530 	if (hslot->count > 10)
2531 		return NULL;
2532 
2533 	result = NULL;
2534 	sk_for_each_rcu(sk, &hslot->head) {
2535 		if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
2536 					rmt_port, rmt_addr, dif, sdif, hnum)) {
2537 			if (result)
2538 				return NULL;
2539 			result = sk;
2540 		}
2541 	}
2542 
2543 	return result;
2544 }
2545 
2546 /* For unicast we should only early demux connected sockets or we can
2547  * break forwarding setups.  The chains here can be long so only check
2548  * if the first socket is an exact match and if not move on.
2549  */
__udp4_lib_demux_lookup(struct net * net,__be16 loc_port,__be32 loc_addr,__be16 rmt_port,__be32 rmt_addr,int dif,int sdif)2550 static struct sock *__udp4_lib_demux_lookup(struct net *net,
2551 					    __be16 loc_port, __be32 loc_addr,
2552 					    __be16 rmt_port, __be32 rmt_addr,
2553 					    int dif, int sdif)
2554 {
2555 	INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
2556 	unsigned short hnum = ntohs(loc_port);
2557 	unsigned int hash2, slot2;
2558 	struct udp_hslot *hslot2;
2559 	__portpair ports;
2560 	struct sock *sk;
2561 
2562 	hash2 = ipv4_portaddr_hash(net, loc_addr, hnum);
2563 	slot2 = hash2 & udp_table.mask;
2564 	hslot2 = &udp_table.hash2[slot2];
2565 	ports = INET_COMBINED_PORTS(rmt_port, hnum);
2566 
2567 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
2568 		if (inet_match(net, sk, acookie, ports, dif, sdif))
2569 			return sk;
2570 		/* Only check first socket in chain */
2571 		break;
2572 	}
2573 	return NULL;
2574 }
2575 
udp_v4_early_demux(struct sk_buff * skb)2576 int udp_v4_early_demux(struct sk_buff *skb)
2577 {
2578 	struct net *net = dev_net(skb->dev);
2579 	struct in_device *in_dev = NULL;
2580 	const struct iphdr *iph;
2581 	const struct udphdr *uh;
2582 	struct sock *sk = NULL;
2583 	struct dst_entry *dst;
2584 	int dif = skb->dev->ifindex;
2585 	int sdif = inet_sdif(skb);
2586 	int ours;
2587 
2588 	/* validate the packet */
2589 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
2590 		return 0;
2591 
2592 	iph = ip_hdr(skb);
2593 	uh = udp_hdr(skb);
2594 
2595 	if (skb->pkt_type == PACKET_MULTICAST) {
2596 		in_dev = __in_dev_get_rcu(skb->dev);
2597 
2598 		if (!in_dev)
2599 			return 0;
2600 
2601 		ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
2602 				       iph->protocol);
2603 		if (!ours)
2604 			return 0;
2605 
2606 		sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
2607 						   uh->source, iph->saddr,
2608 						   dif, sdif);
2609 	} else if (skb->pkt_type == PACKET_HOST) {
2610 		sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
2611 					     uh->source, iph->saddr, dif, sdif);
2612 	}
2613 
2614 	if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
2615 		return 0;
2616 
2617 	skb->sk = sk;
2618 	skb->destructor = sock_efree;
2619 	dst = rcu_dereference(sk->sk_rx_dst);
2620 
2621 	if (dst)
2622 		dst = dst_check(dst, 0);
2623 	if (dst) {
2624 		u32 itag = 0;
2625 
2626 		/* set noref for now.
2627 		 * any place which wants to hold dst has to call
2628 		 * dst_hold_safe()
2629 		 */
2630 		skb_dst_set_noref(skb, dst);
2631 
2632 		/* for unconnected multicast sockets we need to validate
2633 		 * the source on each packet
2634 		 */
2635 		if (!inet_sk(sk)->inet_daddr && in_dev)
2636 			return ip_mc_validate_source(skb, iph->daddr,
2637 						     iph->saddr,
2638 						     iph->tos & IPTOS_RT_MASK,
2639 						     skb->dev, in_dev, &itag);
2640 	}
2641 	return 0;
2642 }
2643 
udp_rcv(struct sk_buff * skb)2644 int udp_rcv(struct sk_buff *skb)
2645 {
2646 	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
2647 }
2648 
udp_destroy_sock(struct sock * sk)2649 void udp_destroy_sock(struct sock *sk)
2650 {
2651 	struct udp_sock *up = udp_sk(sk);
2652 	bool slow = lock_sock_fast(sk);
2653 
2654 	/* protects from races with udp_abort() */
2655 	sock_set_flag(sk, SOCK_DEAD);
2656 	udp_flush_pending_frames(sk);
2657 	unlock_sock_fast(sk, slow);
2658 	if (static_branch_unlikely(&udp_encap_needed_key)) {
2659 		if (up->encap_type) {
2660 			void (*encap_destroy)(struct sock *sk);
2661 			encap_destroy = READ_ONCE(up->encap_destroy);
2662 			if (encap_destroy)
2663 				encap_destroy(sk);
2664 		}
2665 		if (up->encap_enabled)
2666 			static_branch_dec(&udp_encap_needed_key);
2667 	}
2668 }
2669 
2670 /*
2671  *	Socket option code for UDP
2672  */
udp_lib_setsockopt(struct sock * sk,int level,int optname,sockptr_t optval,unsigned int optlen,int (* push_pending_frames)(struct sock *))2673 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
2674 		       sockptr_t optval, unsigned int optlen,
2675 		       int (*push_pending_frames)(struct sock *))
2676 {
2677 	struct udp_sock *up = udp_sk(sk);
2678 	int val, valbool;
2679 	int err = 0;
2680 	int is_udplite = IS_UDPLITE(sk);
2681 
2682 	if (optlen < sizeof(int))
2683 		return -EINVAL;
2684 
2685 	if (copy_from_sockptr(&val, optval, sizeof(val)))
2686 		return -EFAULT;
2687 
2688 	valbool = val ? 1 : 0;
2689 
2690 	switch (optname) {
2691 	case UDP_CORK:
2692 		if (val != 0) {
2693 			WRITE_ONCE(up->corkflag, 1);
2694 		} else {
2695 			WRITE_ONCE(up->corkflag, 0);
2696 			lock_sock(sk);
2697 			push_pending_frames(sk);
2698 			release_sock(sk);
2699 		}
2700 		break;
2701 
2702 	case UDP_ENCAP:
2703 		switch (val) {
2704 		case 0:
2705 #ifdef CONFIG_XFRM
2706 		case UDP_ENCAP_ESPINUDP:
2707 		case UDP_ENCAP_ESPINUDP_NON_IKE:
2708 #if IS_ENABLED(CONFIG_IPV6)
2709 			if (sk->sk_family == AF_INET6)
2710 				up->encap_rcv = ipv6_stub->xfrm6_udp_encap_rcv;
2711 			else
2712 #endif
2713 				up->encap_rcv = xfrm4_udp_encap_rcv;
2714 #endif
2715 			fallthrough;
2716 		case UDP_ENCAP_L2TPINUDP:
2717 			up->encap_type = val;
2718 			lock_sock(sk);
2719 			udp_tunnel_encap_enable(sk->sk_socket);
2720 			release_sock(sk);
2721 			break;
2722 		default:
2723 			err = -ENOPROTOOPT;
2724 			break;
2725 		}
2726 		break;
2727 
2728 	case UDP_NO_CHECK6_TX:
2729 		up->no_check6_tx = valbool;
2730 		break;
2731 
2732 	case UDP_NO_CHECK6_RX:
2733 		up->no_check6_rx = valbool;
2734 		break;
2735 
2736 	case UDP_SEGMENT:
2737 		if (val < 0 || val > USHRT_MAX)
2738 			return -EINVAL;
2739 		WRITE_ONCE(up->gso_size, val);
2740 		break;
2741 
2742 	case UDP_GRO:
2743 		lock_sock(sk);
2744 
2745 		/* when enabling GRO, accept the related GSO packet type */
2746 		if (valbool)
2747 			udp_tunnel_encap_enable(sk->sk_socket);
2748 		up->gro_enabled = valbool;
2749 		up->accept_udp_l4 = valbool;
2750 		release_sock(sk);
2751 		break;
2752 
2753 	/*
2754 	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
2755 	 */
2756 	/* The sender sets actual checksum coverage length via this option.
2757 	 * The case coverage > packet length is handled by send module. */
2758 	case UDPLITE_SEND_CSCOV:
2759 		if (!is_udplite)         /* Disable the option on UDP sockets */
2760 			return -ENOPROTOOPT;
2761 		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
2762 			val = 8;
2763 		else if (val > USHRT_MAX)
2764 			val = USHRT_MAX;
2765 		up->pcslen = val;
2766 		up->pcflag |= UDPLITE_SEND_CC;
2767 		break;
2768 
2769 	/* The receiver specifies a minimum checksum coverage value. To make
2770 	 * sense, this should be set to at least 8 (as done below). If zero is
2771 	 * used, this again means full checksum coverage.                     */
2772 	case UDPLITE_RECV_CSCOV:
2773 		if (!is_udplite)         /* Disable the option on UDP sockets */
2774 			return -ENOPROTOOPT;
2775 		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
2776 			val = 8;
2777 		else if (val > USHRT_MAX)
2778 			val = USHRT_MAX;
2779 		up->pcrlen = val;
2780 		up->pcflag |= UDPLITE_RECV_CC;
2781 		break;
2782 
2783 	default:
2784 		err = -ENOPROTOOPT;
2785 		break;
2786 	}
2787 
2788 	return err;
2789 }
2790 EXPORT_SYMBOL(udp_lib_setsockopt);
2791 
udp_setsockopt(struct sock * sk,int level,int optname,sockptr_t optval,unsigned int optlen)2792 int udp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
2793 		   unsigned int optlen)
2794 {
2795 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2796 		return udp_lib_setsockopt(sk, level, optname,
2797 					  optval, optlen,
2798 					  udp_push_pending_frames);
2799 	return ip_setsockopt(sk, level, optname, optval, optlen);
2800 }
2801 
udp_lib_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)2802 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
2803 		       char __user *optval, int __user *optlen)
2804 {
2805 	struct udp_sock *up = udp_sk(sk);
2806 	int val, len;
2807 
2808 	if (get_user(len, optlen))
2809 		return -EFAULT;
2810 
2811 	len = min_t(unsigned int, len, sizeof(int));
2812 
2813 	if (len < 0)
2814 		return -EINVAL;
2815 
2816 	switch (optname) {
2817 	case UDP_CORK:
2818 		val = READ_ONCE(up->corkflag);
2819 		break;
2820 
2821 	case UDP_ENCAP:
2822 		val = up->encap_type;
2823 		break;
2824 
2825 	case UDP_NO_CHECK6_TX:
2826 		val = up->no_check6_tx;
2827 		break;
2828 
2829 	case UDP_NO_CHECK6_RX:
2830 		val = up->no_check6_rx;
2831 		break;
2832 
2833 	case UDP_SEGMENT:
2834 		val = READ_ONCE(up->gso_size);
2835 		break;
2836 
2837 	case UDP_GRO:
2838 		val = up->gro_enabled;
2839 		break;
2840 
2841 	/* The following two cannot be changed on UDP sockets, the return is
2842 	 * always 0 (which corresponds to the full checksum coverage of UDP). */
2843 	case UDPLITE_SEND_CSCOV:
2844 		val = up->pcslen;
2845 		break;
2846 
2847 	case UDPLITE_RECV_CSCOV:
2848 		val = up->pcrlen;
2849 		break;
2850 
2851 	default:
2852 		return -ENOPROTOOPT;
2853 	}
2854 
2855 	if (put_user(len, optlen))
2856 		return -EFAULT;
2857 	if (copy_to_user(optval, &val, len))
2858 		return -EFAULT;
2859 	return 0;
2860 }
2861 EXPORT_SYMBOL(udp_lib_getsockopt);
2862 
udp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)2863 int udp_getsockopt(struct sock *sk, int level, int optname,
2864 		   char __user *optval, int __user *optlen)
2865 {
2866 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2867 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2868 	return ip_getsockopt(sk, level, optname, optval, optlen);
2869 }
2870 
2871 /**
2872  * 	udp_poll - wait for a UDP event.
2873  *	@file: - file struct
2874  *	@sock: - socket
2875  *	@wait: - poll table
2876  *
2877  *	This is same as datagram poll, except for the special case of
2878  *	blocking sockets. If application is using a blocking fd
2879  *	and a packet with checksum error is in the queue;
2880  *	then it could get return from select indicating data available
2881  *	but then block when reading it. Add special case code
2882  *	to work around these arguably broken applications.
2883  */
udp_poll(struct file * file,struct socket * sock,poll_table * wait)2884 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
2885 {
2886 	__poll_t mask = datagram_poll(file, sock, wait);
2887 	struct sock *sk = sock->sk;
2888 
2889 	if (!skb_queue_empty_lockless(&udp_sk(sk)->reader_queue))
2890 		mask |= EPOLLIN | EPOLLRDNORM;
2891 
2892 	/* Check for false positives due to checksum errors */
2893 	if ((mask & EPOLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
2894 	    !(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)
2895 		mask &= ~(EPOLLIN | EPOLLRDNORM);
2896 
2897 	/* psock ingress_msg queue should not contain any bad checksum frames */
2898 	if (sk_is_readable(sk))
2899 		mask |= EPOLLIN | EPOLLRDNORM;
2900 	return mask;
2901 
2902 }
2903 EXPORT_SYMBOL(udp_poll);
2904 
udp_abort(struct sock * sk,int err)2905 int udp_abort(struct sock *sk, int err)
2906 {
2907 	lock_sock(sk);
2908 
2909 	/* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing
2910 	 * with close()
2911 	 */
2912 	if (sock_flag(sk, SOCK_DEAD))
2913 		goto out;
2914 
2915 	sk->sk_err = err;
2916 	sk_error_report(sk);
2917 	__udp_disconnect(sk, 0);
2918 
2919 out:
2920 	release_sock(sk);
2921 
2922 	return 0;
2923 }
2924 EXPORT_SYMBOL_GPL(udp_abort);
2925 
2926 struct proto udp_prot = {
2927 	.name			= "UDP",
2928 	.owner			= THIS_MODULE,
2929 	.close			= udp_lib_close,
2930 	.pre_connect		= udp_pre_connect,
2931 	.connect		= ip4_datagram_connect,
2932 	.disconnect		= udp_disconnect,
2933 	.ioctl			= udp_ioctl,
2934 	.init			= udp_init_sock,
2935 	.destroy		= udp_destroy_sock,
2936 	.setsockopt		= udp_setsockopt,
2937 	.getsockopt		= udp_getsockopt,
2938 	.sendmsg		= udp_sendmsg,
2939 	.recvmsg		= udp_recvmsg,
2940 	.sendpage		= udp_sendpage,
2941 	.release_cb		= ip4_datagram_release_cb,
2942 	.hash			= udp_lib_hash,
2943 	.unhash			= udp_lib_unhash,
2944 	.rehash			= udp_v4_rehash,
2945 	.get_port		= udp_v4_get_port,
2946 	.put_port		= udp_lib_unhash,
2947 #ifdef CONFIG_BPF_SYSCALL
2948 	.psock_update_sk_prot	= udp_bpf_update_proto,
2949 #endif
2950 	.memory_allocated	= &udp_memory_allocated,
2951 	.per_cpu_fw_alloc	= &udp_memory_per_cpu_fw_alloc,
2952 
2953 	.sysctl_mem		= sysctl_udp_mem,
2954 	.sysctl_wmem_offset	= offsetof(struct net, ipv4.sysctl_udp_wmem_min),
2955 	.sysctl_rmem_offset	= offsetof(struct net, ipv4.sysctl_udp_rmem_min),
2956 	.obj_size		= sizeof(struct udp_sock),
2957 	.h.udp_table		= &udp_table,
2958 	.diag_destroy		= udp_abort,
2959 };
2960 EXPORT_SYMBOL(udp_prot);
2961 
2962 /* ------------------------------------------------------------------------ */
2963 #ifdef CONFIG_PROC_FS
2964 
udp_get_first(struct seq_file * seq,int start)2965 static struct sock *udp_get_first(struct seq_file *seq, int start)
2966 {
2967 	struct udp_iter_state *state = seq->private;
2968 	struct net *net = seq_file_net(seq);
2969 	struct udp_seq_afinfo *afinfo;
2970 	struct sock *sk;
2971 
2972 	if (state->bpf_seq_afinfo)
2973 		afinfo = state->bpf_seq_afinfo;
2974 	else
2975 		afinfo = pde_data(file_inode(seq->file));
2976 
2977 	for (state->bucket = start; state->bucket <= afinfo->udp_table->mask;
2978 	     ++state->bucket) {
2979 		struct udp_hslot *hslot = &afinfo->udp_table->hash[state->bucket];
2980 
2981 		if (hlist_empty(&hslot->head))
2982 			continue;
2983 
2984 		spin_lock_bh(&hslot->lock);
2985 		sk_for_each(sk, &hslot->head) {
2986 			if (!net_eq(sock_net(sk), net))
2987 				continue;
2988 			if (afinfo->family == AF_UNSPEC ||
2989 			    sk->sk_family == afinfo->family)
2990 				goto found;
2991 		}
2992 		spin_unlock_bh(&hslot->lock);
2993 	}
2994 	sk = NULL;
2995 found:
2996 	return sk;
2997 }
2998 
udp_get_next(struct seq_file * seq,struct sock * sk)2999 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
3000 {
3001 	struct udp_iter_state *state = seq->private;
3002 	struct net *net = seq_file_net(seq);
3003 	struct udp_seq_afinfo *afinfo;
3004 
3005 	if (state->bpf_seq_afinfo)
3006 		afinfo = state->bpf_seq_afinfo;
3007 	else
3008 		afinfo = pde_data(file_inode(seq->file));
3009 
3010 	do {
3011 		sk = sk_next(sk);
3012 	} while (sk && (!net_eq(sock_net(sk), net) ||
3013 			(afinfo->family != AF_UNSPEC &&
3014 			 sk->sk_family != afinfo->family)));
3015 
3016 	if (!sk) {
3017 		if (state->bucket <= afinfo->udp_table->mask)
3018 			spin_unlock_bh(&afinfo->udp_table->hash[state->bucket].lock);
3019 		return udp_get_first(seq, state->bucket + 1);
3020 	}
3021 	return sk;
3022 }
3023 
udp_get_idx(struct seq_file * seq,loff_t pos)3024 static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
3025 {
3026 	struct sock *sk = udp_get_first(seq, 0);
3027 
3028 	if (sk)
3029 		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
3030 			--pos;
3031 	return pos ? NULL : sk;
3032 }
3033 
udp_seq_start(struct seq_file * seq,loff_t * pos)3034 void *udp_seq_start(struct seq_file *seq, loff_t *pos)
3035 {
3036 	struct udp_iter_state *state = seq->private;
3037 	state->bucket = MAX_UDP_PORTS;
3038 
3039 	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
3040 }
3041 EXPORT_SYMBOL(udp_seq_start);
3042 
udp_seq_next(struct seq_file * seq,void * v,loff_t * pos)3043 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3044 {
3045 	struct sock *sk;
3046 
3047 	if (v == SEQ_START_TOKEN)
3048 		sk = udp_get_idx(seq, 0);
3049 	else
3050 		sk = udp_get_next(seq, v);
3051 
3052 	++*pos;
3053 	return sk;
3054 }
3055 EXPORT_SYMBOL(udp_seq_next);
3056 
udp_seq_stop(struct seq_file * seq,void * v)3057 void udp_seq_stop(struct seq_file *seq, void *v)
3058 {
3059 	struct udp_iter_state *state = seq->private;
3060 	struct udp_seq_afinfo *afinfo;
3061 
3062 	if (state->bpf_seq_afinfo)
3063 		afinfo = state->bpf_seq_afinfo;
3064 	else
3065 		afinfo = pde_data(file_inode(seq->file));
3066 
3067 	if (state->bucket <= afinfo->udp_table->mask)
3068 		spin_unlock_bh(&afinfo->udp_table->hash[state->bucket].lock);
3069 }
3070 EXPORT_SYMBOL(udp_seq_stop);
3071 
3072 /* ------------------------------------------------------------------------ */
udp4_format_sock(struct sock * sp,struct seq_file * f,int bucket)3073 static void udp4_format_sock(struct sock *sp, struct seq_file *f,
3074 		int bucket)
3075 {
3076 	struct inet_sock *inet = inet_sk(sp);
3077 	__be32 dest = inet->inet_daddr;
3078 	__be32 src  = inet->inet_rcv_saddr;
3079 	__u16 destp	  = ntohs(inet->inet_dport);
3080 	__u16 srcp	  = ntohs(inet->inet_sport);
3081 
3082 	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
3083 		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
3084 		bucket, src, srcp, dest, destp, sp->sk_state,
3085 		sk_wmem_alloc_get(sp),
3086 		udp_rqueue_get(sp),
3087 		0, 0L, 0,
3088 		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
3089 		0, sock_i_ino(sp),
3090 		refcount_read(&sp->sk_refcnt), sp,
3091 		atomic_read(&sp->sk_drops));
3092 }
3093 
udp4_seq_show(struct seq_file * seq,void * v)3094 int udp4_seq_show(struct seq_file *seq, void *v)
3095 {
3096 	seq_setwidth(seq, 127);
3097 	if (v == SEQ_START_TOKEN)
3098 		seq_puts(seq, "   sl  local_address rem_address   st tx_queue "
3099 			   "rx_queue tr tm->when retrnsmt   uid  timeout "
3100 			   "inode ref pointer drops");
3101 	else {
3102 		struct udp_iter_state *state = seq->private;
3103 
3104 		udp4_format_sock(v, seq, state->bucket);
3105 	}
3106 	seq_pad(seq, '\n');
3107 	return 0;
3108 }
3109 
3110 #ifdef CONFIG_BPF_SYSCALL
3111 struct bpf_iter__udp {
3112 	__bpf_md_ptr(struct bpf_iter_meta *, meta);
3113 	__bpf_md_ptr(struct udp_sock *, udp_sk);
3114 	uid_t uid __aligned(8);
3115 	int bucket __aligned(8);
3116 };
3117 
udp_prog_seq_show(struct bpf_prog * prog,struct bpf_iter_meta * meta,struct udp_sock * udp_sk,uid_t uid,int bucket)3118 static int udp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3119 			     struct udp_sock *udp_sk, uid_t uid, int bucket)
3120 {
3121 	struct bpf_iter__udp ctx;
3122 
3123 	meta->seq_num--;  /* skip SEQ_START_TOKEN */
3124 	ctx.meta = meta;
3125 	ctx.udp_sk = udp_sk;
3126 	ctx.uid = uid;
3127 	ctx.bucket = bucket;
3128 	return bpf_iter_run_prog(prog, &ctx);
3129 }
3130 
bpf_iter_udp_seq_show(struct seq_file * seq,void * v)3131 static int bpf_iter_udp_seq_show(struct seq_file *seq, void *v)
3132 {
3133 	struct udp_iter_state *state = seq->private;
3134 	struct bpf_iter_meta meta;
3135 	struct bpf_prog *prog;
3136 	struct sock *sk = v;
3137 	uid_t uid;
3138 
3139 	if (v == SEQ_START_TOKEN)
3140 		return 0;
3141 
3142 	uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3143 	meta.seq = seq;
3144 	prog = bpf_iter_get_info(&meta, false);
3145 	return udp_prog_seq_show(prog, &meta, v, uid, state->bucket);
3146 }
3147 
bpf_iter_udp_seq_stop(struct seq_file * seq,void * v)3148 static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v)
3149 {
3150 	struct bpf_iter_meta meta;
3151 	struct bpf_prog *prog;
3152 
3153 	if (!v) {
3154 		meta.seq = seq;
3155 		prog = bpf_iter_get_info(&meta, true);
3156 		if (prog)
3157 			(void)udp_prog_seq_show(prog, &meta, v, 0, 0);
3158 	}
3159 
3160 	udp_seq_stop(seq, v);
3161 }
3162 
3163 static const struct seq_operations bpf_iter_udp_seq_ops = {
3164 	.start		= udp_seq_start,
3165 	.next		= udp_seq_next,
3166 	.stop		= bpf_iter_udp_seq_stop,
3167 	.show		= bpf_iter_udp_seq_show,
3168 };
3169 #endif
3170 
3171 const struct seq_operations udp_seq_ops = {
3172 	.start		= udp_seq_start,
3173 	.next		= udp_seq_next,
3174 	.stop		= udp_seq_stop,
3175 	.show		= udp4_seq_show,
3176 };
3177 EXPORT_SYMBOL(udp_seq_ops);
3178 
3179 static struct udp_seq_afinfo udp4_seq_afinfo = {
3180 	.family		= AF_INET,
3181 	.udp_table	= &udp_table,
3182 };
3183 
udp4_proc_init_net(struct net * net)3184 static int __net_init udp4_proc_init_net(struct net *net)
3185 {
3186 	if (!proc_create_net_data("udp", 0444, net->proc_net, &udp_seq_ops,
3187 			sizeof(struct udp_iter_state), &udp4_seq_afinfo))
3188 		return -ENOMEM;
3189 	return 0;
3190 }
3191 
udp4_proc_exit_net(struct net * net)3192 static void __net_exit udp4_proc_exit_net(struct net *net)
3193 {
3194 	remove_proc_entry("udp", net->proc_net);
3195 }
3196 
3197 static struct pernet_operations udp4_net_ops = {
3198 	.init = udp4_proc_init_net,
3199 	.exit = udp4_proc_exit_net,
3200 };
3201 
udp4_proc_init(void)3202 int __init udp4_proc_init(void)
3203 {
3204 	return register_pernet_subsys(&udp4_net_ops);
3205 }
3206 
udp4_proc_exit(void)3207 void udp4_proc_exit(void)
3208 {
3209 	unregister_pernet_subsys(&udp4_net_ops);
3210 }
3211 #endif /* CONFIG_PROC_FS */
3212 
3213 static __initdata unsigned long uhash_entries;
set_uhash_entries(char * str)3214 static int __init set_uhash_entries(char *str)
3215 {
3216 	ssize_t ret;
3217 
3218 	if (!str)
3219 		return 0;
3220 
3221 	ret = kstrtoul(str, 0, &uhash_entries);
3222 	if (ret)
3223 		return 0;
3224 
3225 	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
3226 		uhash_entries = UDP_HTABLE_SIZE_MIN;
3227 	return 1;
3228 }
3229 __setup("uhash_entries=", set_uhash_entries);
3230 
udp_table_init(struct udp_table * table,const char * name)3231 void __init udp_table_init(struct udp_table *table, const char *name)
3232 {
3233 	unsigned int i;
3234 
3235 	table->hash = alloc_large_system_hash(name,
3236 					      2 * sizeof(struct udp_hslot),
3237 					      uhash_entries,
3238 					      21, /* one slot per 2 MB */
3239 					      0,
3240 					      &table->log,
3241 					      &table->mask,
3242 					      UDP_HTABLE_SIZE_MIN,
3243 					      64 * 1024);
3244 
3245 	table->hash2 = table->hash + (table->mask + 1);
3246 	for (i = 0; i <= table->mask; i++) {
3247 		INIT_HLIST_HEAD(&table->hash[i].head);
3248 		table->hash[i].count = 0;
3249 		spin_lock_init(&table->hash[i].lock);
3250 	}
3251 	for (i = 0; i <= table->mask; i++) {
3252 		INIT_HLIST_HEAD(&table->hash2[i].head);
3253 		table->hash2[i].count = 0;
3254 		spin_lock_init(&table->hash2[i].lock);
3255 	}
3256 }
3257 
udp_flow_hashrnd(void)3258 u32 udp_flow_hashrnd(void)
3259 {
3260 	static u32 hashrnd __read_mostly;
3261 
3262 	net_get_random_once(&hashrnd, sizeof(hashrnd));
3263 
3264 	return hashrnd;
3265 }
3266 EXPORT_SYMBOL(udp_flow_hashrnd);
3267 
udp_sysctl_init(struct net * net)3268 static int __net_init udp_sysctl_init(struct net *net)
3269 {
3270 	net->ipv4.sysctl_udp_rmem_min = PAGE_SIZE;
3271 	net->ipv4.sysctl_udp_wmem_min = PAGE_SIZE;
3272 
3273 #ifdef CONFIG_NET_L3_MASTER_DEV
3274 	net->ipv4.sysctl_udp_l3mdev_accept = 0;
3275 #endif
3276 
3277 	return 0;
3278 }
3279 
3280 static struct pernet_operations __net_initdata udp_sysctl_ops = {
3281 	.init	= udp_sysctl_init,
3282 };
3283 
3284 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
DEFINE_BPF_ITER_FUNC(udp,struct bpf_iter_meta * meta,struct udp_sock * udp_sk,uid_t uid,int bucket)3285 DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta,
3286 		     struct udp_sock *udp_sk, uid_t uid, int bucket)
3287 
3288 static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux)
3289 {
3290 	struct udp_iter_state *st = priv_data;
3291 	struct udp_seq_afinfo *afinfo;
3292 	int ret;
3293 
3294 	afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
3295 	if (!afinfo)
3296 		return -ENOMEM;
3297 
3298 	afinfo->family = AF_UNSPEC;
3299 	afinfo->udp_table = &udp_table;
3300 	st->bpf_seq_afinfo = afinfo;
3301 	ret = bpf_iter_init_seq_net(priv_data, aux);
3302 	if (ret)
3303 		kfree(afinfo);
3304 	return ret;
3305 }
3306 
bpf_iter_fini_udp(void * priv_data)3307 static void bpf_iter_fini_udp(void *priv_data)
3308 {
3309 	struct udp_iter_state *st = priv_data;
3310 
3311 	kfree(st->bpf_seq_afinfo);
3312 	bpf_iter_fini_seq_net(priv_data);
3313 }
3314 
3315 static const struct bpf_iter_seq_info udp_seq_info = {
3316 	.seq_ops		= &bpf_iter_udp_seq_ops,
3317 	.init_seq_private	= bpf_iter_init_udp,
3318 	.fini_seq_private	= bpf_iter_fini_udp,
3319 	.seq_priv_size		= sizeof(struct udp_iter_state),
3320 };
3321 
3322 static struct bpf_iter_reg udp_reg_info = {
3323 	.target			= "udp",
3324 	.ctx_arg_info_size	= 1,
3325 	.ctx_arg_info		= {
3326 		{ offsetof(struct bpf_iter__udp, udp_sk),
3327 		  PTR_TO_BTF_ID_OR_NULL },
3328 	},
3329 	.seq_info		= &udp_seq_info,
3330 };
3331 
bpf_iter_register(void)3332 static void __init bpf_iter_register(void)
3333 {
3334 	udp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UDP];
3335 	if (bpf_iter_reg_target(&udp_reg_info))
3336 		pr_warn("Warning: could not register bpf iterator udp\n");
3337 }
3338 #endif
3339 
udp_init(void)3340 void __init udp_init(void)
3341 {
3342 	unsigned long limit;
3343 	unsigned int i;
3344 
3345 	udp_table_init(&udp_table, "UDP");
3346 	limit = nr_free_buffer_pages() / 8;
3347 	limit = max(limit, 128UL);
3348 	sysctl_udp_mem[0] = limit / 4 * 3;
3349 	sysctl_udp_mem[1] = limit;
3350 	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
3351 
3352 	/* 16 spinlocks per cpu */
3353 	udp_busylocks_log = ilog2(nr_cpu_ids) + 4;
3354 	udp_busylocks = kmalloc(sizeof(spinlock_t) << udp_busylocks_log,
3355 				GFP_KERNEL);
3356 	if (!udp_busylocks)
3357 		panic("UDP: failed to alloc udp_busylocks\n");
3358 	for (i = 0; i < (1U << udp_busylocks_log); i++)
3359 		spin_lock_init(udp_busylocks + i);
3360 
3361 	if (register_pernet_subsys(&udp_sysctl_ops))
3362 		panic("UDP: failed to init sysctl parameters.\n");
3363 
3364 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3365 	bpf_iter_register();
3366 #endif
3367 }
3368