1 /*
2 * sctp_offload - GRO/GSO Offloading for SCTP
3 *
4 * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <linux/kernel.h>
20 #include <linux/kprobes.h>
21 #include <linux/socket.h>
22 #include <linux/sctp.h>
23 #include <linux/proc_fs.h>
24 #include <linux/vmalloc.h>
25 #include <linux/module.h>
26 #include <linux/kfifo.h>
27 #include <linux/time.h>
28 #include <net/net_namespace.h>
29
30 #include <linux/skbuff.h>
31 #include <net/sctp/sctp.h>
32 #include <net/sctp/checksum.h>
33 #include <net/protocol.h>
34
sctp_gso_make_checksum(struct sk_buff * skb)35 static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
36 {
37 skb->ip_summed = CHECKSUM_NONE;
38 skb->csum_not_inet = 0;
39 return sctp_compute_cksum(skb, skb_transport_offset(skb));
40 }
41
sctp_gso_segment(struct sk_buff * skb,netdev_features_t features)42 static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
43 netdev_features_t features)
44 {
45 struct sk_buff *segs = ERR_PTR(-EINVAL);
46 struct sctphdr *sh;
47
48 if (!skb_is_gso_sctp(skb))
49 goto out;
50
51 sh = sctp_hdr(skb);
52 if (!pskb_may_pull(skb, sizeof(*sh)))
53 goto out;
54
55 __skb_pull(skb, sizeof(*sh));
56
57 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
58 /* Packet is from an untrusted source, reset gso_segs. */
59 struct skb_shared_info *pinfo = skb_shinfo(skb);
60 struct sk_buff *frag_iter;
61
62 pinfo->gso_segs = 0;
63 if (skb->len != skb->data_len) {
64 /* Means we have chunks in here too */
65 pinfo->gso_segs++;
66 }
67
68 skb_walk_frags(skb, frag_iter)
69 pinfo->gso_segs++;
70
71 segs = NULL;
72 goto out;
73 }
74
75 segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
76 if (IS_ERR(segs))
77 goto out;
78
79 /* All that is left is update SCTP CRC if necessary */
80 if (!(features & NETIF_F_SCTP_CRC)) {
81 for (skb = segs; skb; skb = skb->next) {
82 if (skb->ip_summed == CHECKSUM_PARTIAL) {
83 sh = sctp_hdr(skb);
84 sh->checksum = sctp_gso_make_checksum(skb);
85 }
86 }
87 }
88
89 out:
90 return segs;
91 }
92
93 static const struct net_offload sctp_offload = {
94 .callbacks = {
95 .gso_segment = sctp_gso_segment,
96 },
97 };
98
99 static const struct net_offload sctp6_offload = {
100 .callbacks = {
101 .gso_segment = sctp_gso_segment,
102 },
103 };
104
105 static const struct skb_checksum_ops crc32c_csum_ops = {
106 .update = sctp_csum_update,
107 .combine = sctp_csum_combine,
108 };
109
sctp_offload_init(void)110 int __init sctp_offload_init(void)
111 {
112 int ret;
113
114 ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
115 if (ret)
116 goto out;
117
118 ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
119 if (ret)
120 goto ipv4;
121
122 crc32c_csum_stub = &crc32c_csum_ops;
123 return ret;
124
125 ipv4:
126 inet_del_offload(&sctp_offload, IPPROTO_SCTP);
127 out:
128 return ret;
129 }
130
