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/protocol.h>
11 #include <net/tcp.h>
12 #include <net/ip6_checksum.h>
13 #include "ip6_offload.h"
14 
15 INDIRECT_CALLABLE_SCOPE
tcp6_gro_receive(struct list_head * head,struct sk_buff * skb)16 struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)
17 {
18 	/* Don't bother verifying checksum if we're going to flush anyway. */
19 	if (!NAPI_GRO_CB(skb)->flush &&
20 	    skb_gro_checksum_validate(skb, IPPROTO_TCP,
21 				      ip6_gro_compute_pseudo)) {
22 		NAPI_GRO_CB(skb)->flush = 1;
23 		return NULL;
24 	}
25 
26 	return tcp_gro_receive(head, skb);
27 }
28 
tcp6_gro_complete(struct sk_buff * skb,int thoff)29 INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb, int thoff)
30 {
31 	const struct ipv6hdr *iph = ipv6_hdr(skb);
32 	struct tcphdr *th = tcp_hdr(skb);
33 
34 	th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
35 				  &iph->daddr, 0);
36 	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
37 
38 	return tcp_gro_complete(skb);
39 }
40 
tcp6_gso_segment(struct sk_buff * skb,netdev_features_t features)41 static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
42 					netdev_features_t features)
43 {
44 	struct tcphdr *th;
45 
46 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
47 		return ERR_PTR(-EINVAL);
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 }
67 static 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 
tcpv6_offload_init(void)75 int __init tcpv6_offload_init(void)
76 {
77 	return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
78 }
79