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 __sum16 sum; 41 42 switch (skb->ip_summed) { 43 case CHECKSUM_COMPLETE: 44 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr, 45 skb->csum)) { 46 skb->ip_summed = CHECKSUM_UNNECESSARY; 47 break; 48 } 49 flush: 50 NAPI_GRO_CB(skb)->flush = 1; 51 return NULL; 52 53 case CHECKSUM_NONE: 54 wsum = ~csum_unfold(csum_ipv6_magic(&iph->saddr, &iph->daddr, 55 skb_gro_len(skb), 56 IPPROTO_TCP, 0)); 57 sum = csum_fold(skb_checksum(skb, 58 skb_gro_offset(skb), 59 skb_gro_len(skb), 60 wsum)); 61 if (sum) 62 goto flush; 63 64 skb->ip_summed = CHECKSUM_UNNECESSARY; 65 break; 66 } 67 68 return tcp_gro_receive(head, skb); 69 } 70 71 static int tcp6_gro_complete(struct sk_buff *skb) 72 { 73 const struct ipv6hdr *iph = ipv6_hdr(skb); 74 struct tcphdr *th = tcp_hdr(skb); 75 76 th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb), 77 &iph->saddr, &iph->daddr, 0); 78 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 79 80 return tcp_gro_complete(skb); 81 } 82 83 static const struct net_offload tcpv6_offload = { 84 .callbacks = { 85 .gso_send_check = tcp_v6_gso_send_check, 86 .gso_segment = tcp_tso_segment, 87 .gro_receive = tcp6_gro_receive, 88 .gro_complete = tcp6_gro_complete, 89 }, 90 }; 91 92 int __init tcpv6_offload_init(void) 93 { 94 return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP); 95 } 96