xref: /kernel/linux/linux-5.10/net/sctp/offload.c (revision 8c2ecf20) 
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
26static __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
34static 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
81out:
82	return segs;
83}
84
85static const struct net_offload sctp_offload = {
86	.callbacks = {
87		.gso_segment = sctp_gso_segment,
88	},
89};
90
91static const struct net_offload sctp6_offload = {
92	.callbacks = {
93		.gso_segment = sctp_gso_segment,
94	},
95};
96
97int __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
112ipv4:
113	inet_del_offload(&sctp_offload, IPPROTO_SCTP);
114out:
115	return ret;
116}
117