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 int tcp_v6_gso_send_check(struct sk_buff *skb) 19 { 20 const struct ipv6hdr *ipv6h; 21 struct tcphdr *th; 22 23 if (!pskb_may_pull(skb, sizeof(*th))) 24 return -EINVAL; 25 26 ipv6h = ipv6_hdr(skb); 27 th = tcp_hdr(skb); 28 29 th->check = 0; 30 skb->ip_summed = CHECKSUM_PARTIAL; 31 __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr); 32 return 0; 33 } 34 35 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head, 36 struct sk_buff *skb) 37 { 38 const struct ipv6hdr *iph = skb_gro_network_header(skb); 39 __wsum wsum; 40 41 /* Don't bother verifying checksum if we're going to flush anyway. */ 42 if (NAPI_GRO_CB(skb)->flush) 43 goto skip_csum; 44 45 wsum = skb->csum; 46 47 switch (skb->ip_summed) { 48 case CHECKSUM_NONE: 49 wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 50 wsum); 51 52 /* fall through */ 53 54 case CHECKSUM_COMPLETE: 55 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr, 56 wsum)) { 57 skb->ip_summed = CHECKSUM_UNNECESSARY; 58 break; 59 } 60 61 NAPI_GRO_CB(skb)->flush = 1; 62 return NULL; 63 } 64 65 skip_csum: 66 return tcp_gro_receive(head, skb); 67 } 68 69 static int tcp6_gro_complete(struct sk_buff *skb, int thoff) 70 { 71 const struct ipv6hdr *iph = ipv6_hdr(skb); 72 struct tcphdr *th = tcp_hdr(skb); 73 74 th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr, 75 &iph->daddr, 0); 76 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 77 78 return tcp_gro_complete(skb); 79 } 80 81 static const struct net_offload tcpv6_offload = { 82 .callbacks = { 83 .gso_send_check = tcp_v6_gso_send_check, 84 .gso_segment = tcp_gso_segment, 85 .gro_receive = tcp6_gro_receive, 86 .gro_complete = tcp6_gro_complete, 87 }, 88 }; 89 90 int __init tcpv6_offload_init(void) 91 { 92 return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP); 93 } 94