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/indirect_call_wrapper.h>
  13 #include <linux/skbuff.h>
  14 #include <net/protocol.h>
  15 #include <net/tcp.h>
  16 #include <net/ip6_checksum.h>
  17 #include "ip6_offload.h"
  18
  19 INDIRECT_CALLABLE_SCOPE
  20 struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)
  21 {
  22         /* Don't bother verifying checksum if we're going to flush anyway. */
  23         if (!NAPI_GRO_CB(skb)->flush &&
  24             skb_gro_checksum_validate(skb, IPPROTO_TCP,
  25                                       ip6_gro_compute_pseudo)) {
  26                 NAPI_GRO_CB(skb)->flush = 1;
  27                 return NULL;
  28         }
  29
  30         return tcp_gro_receive(head, skb);
  31 }
  32
  33 INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb, int thoff)
  34 {
  35         const struct ipv6hdr *iph = ipv6_hdr(skb);
  36         struct tcphdr *th = tcp_hdr(skb);
  37
  38         th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
  39                                   &iph->daddr, 0);
  40         skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
  41
  42         return tcp_gro_complete(skb);
  43 }
  44
  45 static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
  46                                         netdev_features_t features)
  47 {
  48         struct tcphdr *th;
  49
  50         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
  51                 return ERR_PTR(-EINVAL);
  52
  53         if (!pskb_may_pull(skb, sizeof(*th)))
  54                 return ERR_PTR(-EINVAL);
  55
  56         if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
  57                 const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
  58                 struct tcphdr *th = tcp_hdr(skb);
  59
  60                 /* Set up pseudo header, usually expect stack to have done
  61                  * this.
  62                  */
  63
  64                 th->check = 0;
  65                 skb->ip_summed = CHECKSUM_PARTIAL;
  66                 __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
  67         }
  68
  69         return tcp_gso_segment(skb, features);
  70 }
  71 static const struct net_offload tcpv6_offload = {
  72         .callbacks = {
  73                 .gso_segment    =       tcp6_gso_segment,
  74                 .gro_receive    =       tcp6_gro_receive,
  75                 .gro_complete   =       tcp6_gro_complete,
  76         },
  77 };
  78
  79 int __init tcpv6_offload_init(void)
  80 {
  81         return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
  82 }