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kernel/linux-imx6_3.14.28/net/ipv6/tcpv6_offload.c 2.14 KB
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  /*
   *	IPV6 GSO/GRO offload support
   *	Linux INET6 implementation
   *
   *	This program is free software; you can redistribute it and/or
   *      modify it under the terms of the GNU General Public License
   *      as published by the Free Software Foundation; either version
   *      2 of the License, or (at your option) any later version.
   *
   *      TCPv6 GSO/GRO support
   */
  #include <linux/skbuff.h>
  #include <net/protocol.h>
  #include <net/tcp.h>
  #include <net/ip6_checksum.h>
  #include "ip6_offload.h"
  
  static int tcp_v6_gso_send_check(struct sk_buff *skb)
  {
  	const struct ipv6hdr *ipv6h;
  	struct tcphdr *th;
  
  	if (!pskb_may_pull(skb, sizeof(*th)))
  		return -EINVAL;
  
  	ipv6h = ipv6_hdr(skb);
  	th = tcp_hdr(skb);
  
  	th->check = 0;
  	skb->ip_summed = CHECKSUM_PARTIAL;
  	__tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
  	return 0;
  }
  
  static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
  					 struct sk_buff *skb)
  {
  	const struct ipv6hdr *iph = skb_gro_network_header(skb);
  	__wsum wsum;
  
  	/* Don't bother verifying checksum if we're going to flush anyway. */
  	if (NAPI_GRO_CB(skb)->flush)
  		goto skip_csum;
  
  	wsum = NAPI_GRO_CB(skb)->csum;
  
  	switch (skb->ip_summed) {
  	case CHECKSUM_NONE:
  		wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb),
  				    wsum);
  
  		/* fall through */
  
  	case CHECKSUM_COMPLETE:
  		if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
  				  wsum)) {
  			skb->ip_summed = CHECKSUM_UNNECESSARY;
  			break;
  		}
  
  		NAPI_GRO_CB(skb)->flush = 1;
  		return NULL;
  	}
  
  skip_csum:
  	return tcp_gro_receive(head, skb);
  }
  
  static int tcp6_gro_complete(struct sk_buff *skb, int thoff)
  {
  	const struct ipv6hdr *iph = ipv6_hdr(skb);
  	struct tcphdr *th = tcp_hdr(skb);
  
  	th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
  				  &iph->daddr, 0);
  	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
  
  	return tcp_gro_complete(skb);
  }
  
  static const struct net_offload tcpv6_offload = {
  	.callbacks = {
  		.gso_send_check	=	tcp_v6_gso_send_check,
  		.gso_segment	=	tcp_gso_segment,
  		.gro_receive	=	tcp6_gro_receive,
  		.gro_complete	=	tcp6_gro_complete,
  	},
  };
  
  int __init tcpv6_offload_init(void)
  {
  	return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
  }