1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * sctp_offload - GRO/GSO Offloading for SCTP
4 *
5 * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/kernel.h>
11 #include <linux/kprobes.h>
12 #include <linux/socket.h>
13 #include <linux/sctp.h>
14 #include <linux/proc_fs.h>
15 #include <linux/vmalloc.h>
16 #include <linux/module.h>
17 #include <linux/kfifo.h>
18 #include <linux/time.h>
19 #include <net/net_namespace.h>
20
21 #include <linux/skbuff.h>
22 #include <net/sctp/sctp.h>
23 #include <net/sctp/checksum.h>
24 #include <net/protocol.h>
25
sctp_gso_make_checksum(struct sk_buff * skb)26 static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
27 {
28 skb->ip_summed = CHECKSUM_NONE;
29 skb->csum_not_inet = 0;
30 /* csum and csum_start in GSO CB may be needed to do the UDP
31 * checksum when it's a UDP tunneling packet.
32 */
33 SKB_GSO_CB(skb)->csum = (__force __wsum)~0;
34 SKB_GSO_CB(skb)->csum_start = skb_headroom(skb) + skb->len;
35 return sctp_compute_cksum(skb, skb_transport_offset(skb));
36 }
37
sctp_gso_segment(struct sk_buff * skb,netdev_features_t features)38 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
39 netdev_features_t features)
40 {
41 struct sk_buff *segs = ERR_PTR(-EINVAL);
42 struct sctphdr *sh;
43
44 if (!skb_is_gso_sctp(skb))
45 goto out;
46
47 sh = sctp_hdr(skb);
48 if (!pskb_may_pull(skb, sizeof(*sh)))
49 goto out;
50
51 __skb_pull(skb, sizeof(*sh));
52
53 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
54 /* Packet is from an untrusted source, reset gso_segs. */
55 struct skb_shared_info *pinfo = skb_shinfo(skb);
56 struct sk_buff *frag_iter;
57
58 pinfo->gso_segs = 0;
59 if (skb->len != skb->data_len) {
60 /* Means we have chunks in here too */
61 pinfo->gso_segs++;
62 }
63
64 skb_walk_frags(skb, frag_iter)
65 pinfo->gso_segs++;
66
67 segs = NULL;
68 goto out;
69 }
70
71 segs = skb_segment(skb, (features | NETIF_F_HW_CSUM) & ~NETIF_F_SG);
72 if (IS_ERR(segs))
73 goto out;
74
75 /* All that is left is update SCTP CRC if necessary */
76 if (!(features & NETIF_F_SCTP_CRC)) {
77 for (skb = segs; skb; skb = skb->next) {
78 if (skb->ip_summed == CHECKSUM_PARTIAL) {
79 sh = sctp_hdr(skb);
80 sh->checksum = sctp_gso_make_checksum(skb);
81 }
82 }
83 }
84
85 out:
86 return segs;
87 }
88
89 static const struct net_offload sctp_offload = {
90 .callbacks = {
91 .gso_segment = sctp_gso_segment,
92 },
93 };
94
95 static const struct net_offload sctp6_offload = {
96 .callbacks = {
97 .gso_segment = sctp_gso_segment,
98 },
99 };
100
sctp_offload_init(void)101 int __init sctp_offload_init(void)
102 {
103 int ret;
104
105 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
106 if (ret)
107 goto out;
108
109 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
110 if (ret)
111 goto ipv4;
112
113 crc32c_csum_stub = &sctp_csum_ops;
114 return ret;
115
116 ipv4:
117 inet_del_offload(&sctp_offload, IPPROTO_SCTP);
118 out:
119 return ret;
120 }
121