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  *		Definitions for the UDP protocol.
8  *
9  * Version:	@(#)udp.h	1.0.2	04/28/93
10  *
11  * Author:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  */
13 #ifndef _LINUX_UDP_H
14 #define _LINUX_UDP_H
15 
16 #include <net/inet_sock.h>
17 #include <linux/skbuff.h>
18 #include <net/netns/hash.h>
19 #include <uapi/linux/udp.h>
20 
udp_hdr(const struct sk_buff * skb)21 static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
22 {
23 	return (struct udphdr *)skb_transport_header(skb);
24 }
25 
26 #define UDP_HTABLE_SIZE_MIN		(CONFIG_BASE_SMALL ? 128 : 256)
27 
udp_hashfn(const struct net * net,u32 num,u32 mask)28 static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
29 {
30 	return (num + net_hash_mix(net)) & mask;
31 }
32 
33 struct udp_sock {
34 	/* inet_sock has to be the first member */
35 	struct inet_sock inet;
36 #define udp_port_hash		inet.sk.__sk_common.skc_u16hashes[0]
37 #define udp_portaddr_hash	inet.sk.__sk_common.skc_u16hashes[1]
38 #define udp_portaddr_node	inet.sk.__sk_common.skc_portaddr_node
39 	int		 pending;	/* Any pending frames ? */
40 	unsigned int	 corkflag;	/* Cork is required */
41 	__u8		 encap_type;	/* Is this an Encapsulation socket? */
42 	unsigned char	 no_check6_tx:1,/* Send zero UDP6 checksums on TX? */
43 			 no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
44 			 encap_enabled:1, /* This socket enabled encap
45 					   * processing; UDP tunnels and
46 					   * different encapsulation layer set
47 					   * this
48 					   */
49 			 gro_enabled:1,	/* Request GRO aggregation */
50 			 accept_udp_l4:1,
51 			 accept_udp_fraglist:1;
52 	/*
53 	 * Following member retains the information to create a UDP header
54 	 * when the socket is uncorked.
55 	 */
56 	__u16		 len;		/* total length of pending frames */
57 	__u16		 gso_size;
58 	/*
59 	 * Fields specific to UDP-Lite.
60 	 */
61 	__u16		 pcslen;
62 	__u16		 pcrlen;
63 /* indicator bits used by pcflag: */
64 #define UDPLITE_BIT      0x1  		/* set by udplite proto init function */
65 #define UDPLITE_SEND_CC  0x2  		/* set via udplite setsockopt         */
66 #define UDPLITE_RECV_CC  0x4		/* set via udplite setsocktopt        */
67 	__u8		 pcflag;        /* marks socket as UDP-Lite if > 0    */
68 	__u8		 unused[3];
69 	/*
70 	 * For encapsulation sockets.
71 	 */
72 	int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
73 	void (*encap_err_rcv)(struct sock *sk, struct sk_buff *skb, unsigned int udp_offset);
74 	int (*encap_err_lookup)(struct sock *sk, struct sk_buff *skb);
75 	void (*encap_destroy)(struct sock *sk);
76 
77 	/* GRO functions for UDP socket */
78 	struct sk_buff *	(*gro_receive)(struct sock *sk,
79 					       struct list_head *head,
80 					       struct sk_buff *skb);
81 	int			(*gro_complete)(struct sock *sk,
82 						struct sk_buff *skb,
83 						int nhoff);
84 
85 	/* udp_recvmsg try to use this before splicing sk_receive_queue */
86 	struct sk_buff_head	reader_queue ____cacheline_aligned_in_smp;
87 
88 	/* This field is dirtied by udp_recvmsg() */
89 	int		forward_deficit;
90 };
91 
92 #define UDP_MAX_SEGMENTS	(1 << 6UL)
93 
udp_sk(const struct sock * sk)94 static inline struct udp_sock *udp_sk(const struct sock *sk)
95 {
96 	return (struct udp_sock *)sk;
97 }
98 
udp_set_no_check6_tx(struct sock * sk,bool val)99 static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
100 {
101 	udp_sk(sk)->no_check6_tx = val;
102 }
103 
udp_set_no_check6_rx(struct sock * sk,bool val)104 static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
105 {
106 	udp_sk(sk)->no_check6_rx = val;
107 }
108 
udp_get_no_check6_tx(struct sock * sk)109 static inline bool udp_get_no_check6_tx(struct sock *sk)
110 {
111 	return udp_sk(sk)->no_check6_tx;
112 }
113 
udp_get_no_check6_rx(struct sock * sk)114 static inline bool udp_get_no_check6_rx(struct sock *sk)
115 {
116 	return udp_sk(sk)->no_check6_rx;
117 }
118 
udp_cmsg_recv(struct msghdr * msg,struct sock * sk,struct sk_buff * skb)119 static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
120 				 struct sk_buff *skb)
121 {
122 	int gso_size;
123 
124 	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
125 		gso_size = skb_shinfo(skb)->gso_size;
126 		put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size);
127 	}
128 }
129 
udp_unexpected_gso(struct sock * sk,struct sk_buff * skb)130 static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
131 {
132 	if (!skb_is_gso(skb))
133 		return false;
134 
135 	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 && !udp_sk(sk)->accept_udp_l4)
136 		return true;
137 
138 	if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST && !udp_sk(sk)->accept_udp_fraglist)
139 		return true;
140 
141 	return false;
142 }
143 
udp_allow_gso(struct sock * sk)144 static inline void udp_allow_gso(struct sock *sk)
145 {
146 	udp_sk(sk)->accept_udp_l4 = 1;
147 	udp_sk(sk)->accept_udp_fraglist = 1;
148 }
149 
150 #define udp_portaddr_for_each_entry(__sk, list) \
151 	hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
152 
153 #define udp_portaddr_for_each_entry_rcu(__sk, list) \
154 	hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
155 
156 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
157 
158 #endif	/* _LINUX_UDP_H */
159