net/ipv6/tcpv6_offload.c

Source file repositories/reference/linux-study-clean/net/ipv6/tcpv6_offload.c

File Facts

System
Linux kernel
Corpus path
net/ipv6/tcpv6_offload.c
Extension
.c
Size
5053 bytes
Lines
205
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	IPV6 GSO/GRO offload support
 *	Linux INET6 implementation
 *
 *      TCPv6 GSO/GRO support
 */
#include <linux/indirect_call_wrapper.h>
#include <linux/skbuff.h>
#include <net/inet6_hashtables.h>
#include <net/gro.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <net/ip6_checksum.h>
#include "ip6_offload.h"

static void tcp6_check_fraglist_gro(struct list_head *head, struct sk_buff *skb,
				    struct tcphdr *th)
{
#if IS_ENABLED(CONFIG_IPV6)
	const struct ipv6hdr *hdr;
	struct sk_buff *p;
	struct sock *sk;
	struct net *net;
	int iif, sdif;

	p = tcp_gro_lookup(head, th);
	if (p) {
		NAPI_GRO_CB(skb)->is_flist = NAPI_GRO_CB(p)->is_flist;
		return;
	}

	inet6_get_iif_sdif(skb, &iif, &sdif);
	hdr = skb_gro_network_header(skb);
	net = dev_net_rcu(skb->dev);
	sk = __inet6_lookup_established(net, &hdr->saddr, th->source,
					&hdr->daddr, ntohs(th->dest),
					iif, sdif);
	NAPI_GRO_CB(skb)->is_flist = !sk;
	if (sk)
		sock_gen_put(sk);
#endif /* IS_ENABLED(CONFIG_IPV6) */
}

static __always_inline struct sk_buff *tcp6_gro_receive(struct list_head *head,
							struct sk_buff *skb)
{
	struct tcphdr *th;

	/* Don't bother verifying checksum if we're going to flush anyway. */
	if (!NAPI_GRO_CB(skb)->flush &&
	    skb_gro_checksum_validate(skb, IPPROTO_TCP,
				      ip6_gro_compute_pseudo))
		goto flush;

	th = tcp_gro_pull_header(skb);
	if (!th)
		goto flush;

	if (unlikely(skb->dev->features & NETIF_F_GRO_FRAGLIST))
		tcp6_check_fraglist_gro(head, skb, th);

	return tcp_gro_receive(head, skb, th);

flush:
	NAPI_GRO_CB(skb)->flush = 1;
	return NULL;
}

static __always_inline int tcp6_gro_complete(struct sk_buff *skb, int thoff)
{
	const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
	const struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + offset);
	struct tcphdr *th = tcp_hdr(skb);

	if (unlikely(NAPI_GRO_CB(skb)->is_flist)) {
		skb_shinfo(skb)->gso_type |= SKB_GSO_FRAGLIST | SKB_GSO_TCPV6;
		skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;

		__skb_incr_checksum_unnecessary(skb);

		return 0;
	}

	th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
				  &iph->daddr, 0);
	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;

	tcp_gro_complete(skb);
	return 0;

Annotation

Implementation Notes