1/*
2 *	IPV6 GSO/GRO offload support
3 *	Linux INET6 implementation
4 *
5 *	This program is free software; you can redistribute it and/or
6 *      modify it under the terms of the GNU General Public License
7 *      as published by the Free Software Foundation; either version
8 *      2 of the License, or (at your option) any later version.
9 *
10 *      TCPv6 GSO/GRO support
11 */
12#include <linux/skbuff.h>
13#include <net/protocol.h>
14#include <net/tcp.h>
15#include <net/ip6_checksum.h>
16#include "ip6_offload.h"
17
18static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
19					 struct sk_buff *skb)
20{
21	/* Don't bother verifying checksum if we're going to flush anyway. */
22	if (!NAPI_GRO_CB(skb)->flush &&
23	    skb_gro_checksum_validate(skb, IPPROTO_TCP,
24				      ip6_gro_compute_pseudo)) {
25		NAPI_GRO_CB(skb)->flush = 1;
26		return NULL;
27	}
28
29	return tcp_gro_receive(head, skb);
30}
31
32static int tcp6_gro_complete(struct sk_buff *skb, int thoff)
33{
34	const struct ipv6hdr *iph = ipv6_hdr(skb);
35	struct tcphdr *th = tcp_hdr(skb);
36
37	th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
38				  &iph->daddr, 0);
39	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
40
41	return tcp_gro_complete(skb);
42}
43
44static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
45					netdev_features_t features)
46{
47	struct tcphdr *th;
48
49	if (!pskb_may_pull(skb, sizeof(*th)))
50		return ERR_PTR(-EINVAL);
51
52	if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
53		const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
54		struct tcphdr *th = tcp_hdr(skb);
55
56		/* Set up pseudo header, usually expect stack to have done
57		 * this.
58		 */
59
60		th->check = 0;
61		skb->ip_summed = CHECKSUM_PARTIAL;
62		__tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
63	}
64
65	return tcp_gso_segment(skb, features);
66}
67static const struct net_offload tcpv6_offload = {
68	.callbacks = {
69		.gso_segment	=	tcp6_gso_segment,
70		.gro_receive	=	tcp6_gro_receive,
71		.gro_complete	=	tcp6_gro_complete,
72	},
73};
74
75int __init tcpv6_offload_init(void)
76{
77	return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
78}
79