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 gso_reset_checksum(skb, ~0);
31 return sctp_compute_cksum(skb, skb_transport_offset(skb));
32 }
33
sctp_gso_segment(struct sk_buff * skb,netdev_features_t features)34 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
35 netdev_features_t features)
36 {
37 struct sk_buff *segs = ERR_PTR(-EINVAL);
38 struct sctphdr *sh;
39
40 if (!skb_is_gso_sctp(skb))
41 goto out;
42
43 sh = sctp_hdr(skb);
44 if (!pskb_may_pull(skb, sizeof(*sh)))
45 goto out;
46
47 __skb_pull(skb, sizeof(*sh));
48
49 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
50 /* Packet is from an untrusted source, reset gso_segs. */
51 struct skb_shared_info *pinfo = skb_shinfo(skb);
52 struct sk_buff *frag_iter;
53
54 pinfo->gso_segs = 0;
55 if (skb->len != skb->data_len) {
56 /* Means we have chunks in here too */
57 pinfo->gso_segs++;
58 }
59
60 skb_walk_frags(skb, frag_iter)
61 pinfo->gso_segs++;
62
63 segs = NULL;
64 goto out;
65 }
66
67 segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
68 if (IS_ERR(segs))
69 goto out;
70
71 /* All that is left is update SCTP CRC if necessary */
72 if (!(features & NETIF_F_SCTP_CRC)) {
73 for (skb = segs; skb; skb = skb->next) {
74 if (skb->ip_summed == CHECKSUM_PARTIAL) {
75 sh = sctp_hdr(skb);
76 sh->checksum = sctp_gso_make_checksum(skb);
77 }
78 }
79 }
80
81 out:
82 return segs;
83 }
84
85 static const struct net_offload sctp_offload = {
86 .callbacks = {
87 .gso_segment = sctp_gso_segment,
88 },
89 };
90
91 static const struct net_offload sctp6_offload = {
92 .callbacks = {
93 .gso_segment = sctp_gso_segment,
94 },
95 };
96
sctp_offload_init(void)97 int __init sctp_offload_init(void)
98 {
99 int ret;
100
101 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
102 if (ret)
103 goto out;
104
105 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
106 if (ret)
107 goto ipv4;
108
109 crc32c_csum_stub = &sctp_csum_ops;
110 return ret;
111
112 ipv4:
113 inet_del_offload(&sctp_offload, IPPROTO_SCTP);
114 out:
115 return ret;
116 }
117