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 11 #include <linux/kernel.h> 12 #include <linux/socket.h> 13 #include <linux/netdevice.h> 14 #include <linux/skbuff.h> 15 #include <linux/printk.h> 16 17 #include <net/protocol.h> 18 #include <net/ipv6.h> 19 20 #include "ip6_offload.h" 21 22 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 23 { 24 const struct net_offload *ops = NULL; 25 26 for (;;) { 27 struct ipv6_opt_hdr *opth; 28 int len; 29 30 if (proto != NEXTHDR_HOP) { 31 ops = rcu_dereference(inet6_offloads[proto]); 32 33 if (unlikely(!ops)) 34 break; 35 36 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 37 break; 38 } 39 40 if (unlikely(!pskb_may_pull(skb, 8))) 41 break; 42 43 opth = (void *)skb->data; 44 len = ipv6_optlen(opth); 45 46 if (unlikely(!pskb_may_pull(skb, len))) 47 break; 48 49 opth = (void *)skb->data; 50 proto = opth->nexthdr; 51 __skb_pull(skb, len); 52 } 53 54 return proto; 55 } 56 57 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 58 netdev_features_t features) 59 { 60 struct sk_buff *segs = ERR_PTR(-EINVAL); 61 struct ipv6hdr *ipv6h; 62 const struct net_offload *ops; 63 int proto; 64 struct frag_hdr *fptr; 65 unsigned int unfrag_ip6hlen; 66 u8 *prevhdr; 67 int offset = 0; 68 bool encap, udpfrag; 69 int nhoff; 70 71 if (unlikely(skb_shinfo(skb)->gso_type & 72 ~(SKB_GSO_UDP | 73 SKB_GSO_DODGY | 74 SKB_GSO_TCP_ECN | 75 SKB_GSO_GRE | 76 SKB_GSO_GRE_CSUM | 77 SKB_GSO_IPIP | 78 SKB_GSO_SIT | 79 SKB_GSO_UDP_TUNNEL | 80 SKB_GSO_UDP_TUNNEL_CSUM | 81 SKB_GSO_MPLS | 82 SKB_GSO_TCPV6 | 83 0))) 84 goto out; 85 86 skb_reset_network_header(skb); 87 nhoff = skb_network_header(skb) - skb_mac_header(skb); 88 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 89 goto out; 90 91 encap = SKB_GSO_CB(skb)->encap_level > 0; 92 if (encap) 93 features = skb->dev->hw_enc_features & netif_skb_features(skb); 94 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 95 96 ipv6h = ipv6_hdr(skb); 97 __skb_pull(skb, sizeof(*ipv6h)); 98 segs = ERR_PTR(-EPROTONOSUPPORT); 99 100 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 101 102 if (skb->encapsulation && 103 skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP)) 104 udpfrag = proto == IPPROTO_UDP && encap; 105 else 106 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation; 107 108 ops = rcu_dereference(inet6_offloads[proto]); 109 if (likely(ops && ops->callbacks.gso_segment)) { 110 skb_reset_transport_header(skb); 111 segs = ops->callbacks.gso_segment(skb, features); 112 } 113 114 if (IS_ERR(segs)) 115 goto out; 116 117 for (skb = segs; skb; skb = skb->next) { 118 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 119 ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h)); 120 skb->network_header = (u8 *)ipv6h - skb->head; 121 122 if (udpfrag) { 123 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 124 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 125 fptr->frag_off = htons(offset); 126 if (skb->next != NULL) 127 fptr->frag_off |= htons(IP6_MF); 128 offset += (ntohs(ipv6h->payload_len) - 129 sizeof(struct frag_hdr)); 130 } 131 if (encap) 132 skb_reset_inner_headers(skb); 133 } 134 135 out: 136 return segs; 137 } 138 139 /* Return the total length of all the extension hdrs, following the same 140 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 141 */ 142 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 143 const struct net_offload **opps) 144 { 145 struct ipv6_opt_hdr *opth = (void *)iph; 146 int len = 0, proto, optlen = sizeof(*iph); 147 148 proto = iph->nexthdr; 149 for (;;) { 150 if (proto != NEXTHDR_HOP) { 151 *opps = rcu_dereference(inet6_offloads[proto]); 152 if (unlikely(!(*opps))) 153 break; 154 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 155 break; 156 } 157 opth = (void *)opth + optlen; 158 optlen = ipv6_optlen(opth); 159 len += optlen; 160 proto = opth->nexthdr; 161 } 162 return len; 163 } 164 165 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 166 struct sk_buff *skb) 167 { 168 const struct net_offload *ops; 169 struct sk_buff **pp = NULL; 170 struct sk_buff *p; 171 struct ipv6hdr *iph; 172 unsigned int nlen; 173 unsigned int hlen; 174 unsigned int off; 175 u16 flush = 1; 176 int proto; 177 178 off = skb_gro_offset(skb); 179 hlen = off + sizeof(*iph); 180 iph = skb_gro_header_fast(skb, off); 181 if (skb_gro_header_hard(skb, hlen)) { 182 iph = skb_gro_header_slow(skb, hlen, off); 183 if (unlikely(!iph)) 184 goto out; 185 } 186 187 skb_set_network_header(skb, off); 188 skb_gro_pull(skb, sizeof(*iph)); 189 skb_set_transport_header(skb, skb_gro_offset(skb)); 190 191 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 192 193 rcu_read_lock(); 194 proto = iph->nexthdr; 195 ops = rcu_dereference(inet6_offloads[proto]); 196 if (!ops || !ops->callbacks.gro_receive) { 197 __pskb_pull(skb, skb_gro_offset(skb)); 198 proto = ipv6_gso_pull_exthdrs(skb, proto); 199 skb_gro_pull(skb, -skb_transport_offset(skb)); 200 skb_reset_transport_header(skb); 201 __skb_push(skb, skb_gro_offset(skb)); 202 203 ops = rcu_dereference(inet6_offloads[proto]); 204 if (!ops || !ops->callbacks.gro_receive) 205 goto out_unlock; 206 207 iph = ipv6_hdr(skb); 208 } 209 210 NAPI_GRO_CB(skb)->proto = proto; 211 212 flush--; 213 nlen = skb_network_header_len(skb); 214 215 for (p = *head; p; p = p->next) { 216 const struct ipv6hdr *iph2; 217 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 218 219 if (!NAPI_GRO_CB(p)->same_flow) 220 continue; 221 222 iph2 = (struct ipv6hdr *)(p->data + off); 223 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 224 225 /* All fields must match except length and Traffic Class. 226 * XXX skbs on the gro_list have all been parsed and pulled 227 * already so we don't need to compare nlen 228 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 229 * memcmp() alone below is suffcient, right? 230 */ 231 if ((first_word & htonl(0xF00FFFFF)) || 232 memcmp(&iph->nexthdr, &iph2->nexthdr, 233 nlen - offsetof(struct ipv6hdr, nexthdr))) { 234 NAPI_GRO_CB(p)->same_flow = 0; 235 continue; 236 } 237 /* flush if Traffic Class fields are different */ 238 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 239 NAPI_GRO_CB(p)->flush |= flush; 240 241 /* Clear flush_id, there's really no concept of ID in IPv6. */ 242 NAPI_GRO_CB(p)->flush_id = 0; 243 } 244 245 NAPI_GRO_CB(skb)->flush |= flush; 246 247 skb_gro_postpull_rcsum(skb, iph, nlen); 248 249 pp = ops->callbacks.gro_receive(head, skb); 250 251 out_unlock: 252 rcu_read_unlock(); 253 254 out: 255 NAPI_GRO_CB(skb)->flush |= flush; 256 257 return pp; 258 } 259 260 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 261 { 262 const struct net_offload *ops; 263 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 264 int err = -ENOSYS; 265 266 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 267 268 rcu_read_lock(); 269 270 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 271 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 272 goto out_unlock; 273 274 err = ops->callbacks.gro_complete(skb, nhoff); 275 276 out_unlock: 277 rcu_read_unlock(); 278 279 return err; 280 } 281 282 static struct packet_offload ipv6_packet_offload __read_mostly = { 283 .type = cpu_to_be16(ETH_P_IPV6), 284 .callbacks = { 285 .gso_segment = ipv6_gso_segment, 286 .gro_receive = ipv6_gro_receive, 287 .gro_complete = ipv6_gro_complete, 288 }, 289 }; 290 291 static const struct net_offload sit_offload = { 292 .callbacks = { 293 .gso_segment = ipv6_gso_segment, 294 .gro_receive = ipv6_gro_receive, 295 .gro_complete = ipv6_gro_complete, 296 }, 297 }; 298 299 static int __init ipv6_offload_init(void) 300 { 301 302 if (tcpv6_offload_init() < 0) 303 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 304 if (udp_offload_init() < 0) 305 pr_crit("%s: Cannot add UDP protocol offload\n", __func__); 306 if (ipv6_exthdrs_offload_init() < 0) 307 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 308 309 dev_add_offload(&ipv6_packet_offload); 310 311 inet_add_offload(&sit_offload, IPPROTO_IPV6); 312 313 return 0; 314 } 315 316 fs_initcall(ipv6_offload_init); 317