1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	IPV6 GSO/GRO offload support
4  *	Linux INET6 implementation
5  *
6  *      TCPv6 GSO/GRO support
7  */
8 #include <linux/indirect_call_wrapper.h>
9 #include <linux/skbuff.h>
10 #include <net/gro.h>
11 #include <net/protocol.h>
12 #include <net/tcp.h>
13 #include <net/ip6_checksum.h>
14 #include "ip6_offload.h"
15 
16 INDIRECT_CALLABLE_SCOPE
tcp6_gro_receive(struct list_head * head,struct sk_buff * skb)17 struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)
18 {
19 	/* Don't bother verifying checksum if we're going to flush anyway. */
20 	if (!NAPI_GRO_CB(skb)->flush &&
21 	    skb_gro_checksum_validate(skb, IPPROTO_TCP,
22 				      ip6_gro_compute_pseudo)) {
23 		NAPI_GRO_CB(skb)->flush = 1;
24 		return NULL;
25 	}
26 
27 	return tcp_gro_receive(head, skb);
28 }
29 
tcp6_gro_complete(struct sk_buff * skb,int thoff)30 INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb, int thoff)
31 {
32 	const struct ipv6hdr *iph = ipv6_hdr(skb);
33 	struct tcphdr *th = tcp_hdr(skb);
34 
35 	th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
36 				  &iph->daddr, 0);
37 	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
38 
39 	return tcp_gro_complete(skb);
40 }
41 
tcp6_gso_segment(struct sk_buff * skb,netdev_features_t features)42 static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
43 					netdev_features_t features)
44 {
45 	struct tcphdr *th;
46 
47 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
48 		return ERR_PTR(-EINVAL);
49 
50 	if (!pskb_may_pull(skb, sizeof(*th)))
51 		return ERR_PTR(-EINVAL);
52 
53 	if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
54 		const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
55 		struct tcphdr *th = tcp_hdr(skb);
56 
57 		/* Set up pseudo header, usually expect stack to have done
58 		 * this.
59 		 */
60 
61 		th->check = 0;
62 		skb->ip_summed = CHECKSUM_PARTIAL;
63 		__tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
64 	}
65 
66 	return tcp_gso_segment(skb, features);
67 }
68 static const struct net_offload tcpv6_offload = {
69 	.callbacks = {
70 		.gso_segment	=	tcp6_gso_segment,
71 		.gro_receive	=	tcp6_gro_receive,
72 		.gro_complete	=	tcp6_gro_complete,
73 	},
74 };
75 
tcpv6_offload_init(void)76 int __init tcpv6_offload_init(void)
77 {
78 	return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
79 }
80