net/ipv6/tcpv6_offload.c

   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
  18 static struct sk_buff *tcp6_gro_receive(struct list_head *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
  32 static 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
  44 static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
  45                                         netdev_features_t features)
  46 {
  47         struct tcphdr *th;
  48
  49         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
  50                 return ERR_PTR(-EINVAL);
  51
  52         if (!pskb_may_pull(skb, sizeof(*th)))
  53                 return ERR_PTR(-EINVAL);
  54
  55         if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
  56                 const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
  57                 struct tcphdr *th = tcp_hdr(skb);
  58
  59                 /* Set up pseudo header, usually expect stack to have done
  60                  * this.
  61                  */
  62
  63                 th->check = 0;
  64                 skb->ip_summed = CHECKSUM_PARTIAL;
  65                 __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
  66         }
  67
  68         return tcp_gso_segment(skb, features);
  69 }
  70 static const struct net_offload tcpv6_offload = {
  71         .callbacks = {
  72                 .gso_segment    =       tcp6_gso_segment,
  73                 .gro_receive    =       tcp6_gro_receive,
  74                 .gro_complete   =       tcp6_gro_complete,
  75         },
  76 };
  77
  78 int __init tcpv6_offload_init(void)
  79 {
  80         return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
  81 }