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 * UDPv6 GSO support 11 */ 12 #include <linux/skbuff.h> 13 #include <linux/netdevice.h> 14 #include <net/protocol.h> 15 #include <net/ipv6.h> 16 #include <net/udp.h> 17 #include <net/ip6_checksum.h> 18 #include "ip6_offload.h" 19 20 static struct sk_buff *__udp6_gso_segment(struct sk_buff *gso_skb, 21 netdev_features_t features) 22 { 23 const struct ipv6hdr *ip6h = ipv6_hdr(gso_skb); 24 unsigned int mss = skb_shinfo(gso_skb)->gso_size; 25 26 if (!can_checksum_protocol(features, htons(ETH_P_IPV6))) 27 return ERR_PTR(-EIO); 28 29 return __udp_gso_segment(gso_skb, features, mss, 30 udp_v6_check(sizeof(struct udphdr) + mss, 31 &ip6h->saddr, &ip6h->daddr, 0)); 32 } 33 34 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, 35 netdev_features_t features) 36 { 37 struct sk_buff *segs = ERR_PTR(-EINVAL); 38 unsigned int mss; 39 unsigned int unfrag_ip6hlen, unfrag_len; 40 struct frag_hdr *fptr; 41 u8 *packet_start, *prevhdr; 42 u8 nexthdr; 43 u8 frag_hdr_sz = sizeof(struct frag_hdr); 44 __wsum csum; 45 int tnl_hlen; 46 int err; 47 48 mss = skb_shinfo(skb)->gso_size; 49 if (unlikely(skb->len <= mss)) 50 goto out; 51 52 if (skb->encapsulation && skb_shinfo(skb)->gso_type & 53 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM)) 54 segs = skb_udp_tunnel_segment(skb, features, true); 55 else { 56 const struct ipv6hdr *ipv6h; 57 struct udphdr *uh; 58 59 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4))) 60 goto out; 61 62 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 63 goto out; 64 65 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) 66 return __udp6_gso_segment(skb, features); 67 68 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot 69 * do checksum of UDP packets sent as multiple IP fragments. 70 */ 71 72 uh = udp_hdr(skb); 73 ipv6h = ipv6_hdr(skb); 74 75 uh->check = 0; 76 csum = skb_checksum(skb, 0, skb->len, 0); 77 uh->check = udp_v6_check(skb->len, &ipv6h->saddr, 78 &ipv6h->daddr, csum); 79 if (uh->check == 0) 80 uh->check = CSUM_MANGLED_0; 81 82 skb->ip_summed = CHECKSUM_UNNECESSARY; 83 84 /* If there is no outer header we can fake a checksum offload 85 * due to the fact that we have already done the checksum in 86 * software prior to segmenting the frame. 87 */ 88 if (!skb->encap_hdr_csum) 89 features |= NETIF_F_HW_CSUM; 90 91 /* Check if there is enough headroom to insert fragment header. */ 92 tnl_hlen = skb_tnl_header_len(skb); 93 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { 94 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) 95 goto out; 96 } 97 98 /* Find the unfragmentable header and shift it left by frag_hdr_sz 99 * bytes to insert fragment header. 100 */ 101 err = ip6_find_1stfragopt(skb, &prevhdr); 102 if (err < 0) 103 return ERR_PTR(err); 104 unfrag_ip6hlen = err; 105 nexthdr = *prevhdr; 106 *prevhdr = NEXTHDR_FRAGMENT; 107 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) + 108 unfrag_ip6hlen + tnl_hlen; 109 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset; 110 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len); 111 112 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz; 113 skb->mac_header -= frag_hdr_sz; 114 skb->network_header -= frag_hdr_sz; 115 116 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); 117 fptr->nexthdr = nexthdr; 118 fptr->reserved = 0; 119 fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb); 120 121 /* Fragment the skb. ipv6 header and the remaining fields of the 122 * fragment header are updated in ipv6_gso_segment() 123 */ 124 segs = skb_segment(skb, features); 125 } 126 127 out: 128 return segs; 129 } 130 131 static struct sk_buff **udp6_gro_receive(struct sk_buff **head, 132 struct sk_buff *skb) 133 { 134 struct udphdr *uh = udp_gro_udphdr(skb); 135 136 if (unlikely(!uh)) 137 goto flush; 138 139 /* Don't bother verifying checksum if we're going to flush anyway. */ 140 if (NAPI_GRO_CB(skb)->flush) 141 goto skip; 142 143 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 144 ip6_gro_compute_pseudo)) 145 goto flush; 146 else if (uh->check) 147 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, 148 ip6_gro_compute_pseudo); 149 150 skip: 151 NAPI_GRO_CB(skb)->is_ipv6 = 1; 152 return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb); 153 154 flush: 155 NAPI_GRO_CB(skb)->flush = 1; 156 return NULL; 157 } 158 159 static int udp6_gro_complete(struct sk_buff *skb, int nhoff) 160 { 161 const struct ipv6hdr *ipv6h = ipv6_hdr(skb); 162 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 163 164 if (uh->check) { 165 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; 166 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr, 167 &ipv6h->daddr, 0); 168 } else { 169 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; 170 } 171 172 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb); 173 } 174 175 static const struct net_offload udpv6_offload = { 176 .callbacks = { 177 .gso_segment = udp6_ufo_fragment, 178 .gro_receive = udp6_gro_receive, 179 .gro_complete = udp6_gro_complete, 180 }, 181 }; 182 183 int udpv6_offload_init(void) 184 { 185 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); 186 } 187 188 int udpv6_offload_exit(void) 189 { 190 return inet6_del_offload(&udpv6_offload, IPPROTO_UDP); 191 } 192