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 #include <net/inet_common.h> 20 21 #include "ip6_offload.h" 22 23 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 24 { 25 const struct net_offload *ops = NULL; 26 27 for (;;) { 28 struct ipv6_opt_hdr *opth; 29 int len; 30 31 if (proto != NEXTHDR_HOP) { 32 ops = rcu_dereference(inet6_offloads[proto]); 33 34 if (unlikely(!ops)) 35 break; 36 37 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 38 break; 39 } 40 41 if (unlikely(!pskb_may_pull(skb, 8))) 42 break; 43 44 opth = (void *)skb->data; 45 len = ipv6_optlen(opth); 46 47 if (unlikely(!pskb_may_pull(skb, len))) 48 break; 49 50 opth = (void *)skb->data; 51 proto = opth->nexthdr; 52 __skb_pull(skb, len); 53 } 54 55 return proto; 56 } 57 58 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 59 netdev_features_t features) 60 { 61 struct sk_buff *segs = ERR_PTR(-EINVAL); 62 struct ipv6hdr *ipv6h; 63 const struct net_offload *ops; 64 int proto; 65 struct frag_hdr *fptr; 66 unsigned int unfrag_ip6hlen; 67 unsigned int payload_len; 68 u8 *prevhdr; 69 int offset = 0; 70 bool encap, udpfrag; 71 int nhoff; 72 bool gso_partial; 73 74 skb_reset_network_header(skb); 75 nhoff = skb_network_header(skb) - skb_mac_header(skb); 76 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 77 goto out; 78 79 encap = SKB_GSO_CB(skb)->encap_level > 0; 80 if (encap) 81 features &= skb->dev->hw_enc_features; 82 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 83 84 ipv6h = ipv6_hdr(skb); 85 __skb_pull(skb, sizeof(*ipv6h)); 86 segs = ERR_PTR(-EPROTONOSUPPORT); 87 88 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 89 90 if (skb->encapsulation && 91 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 92 udpfrag = proto == IPPROTO_UDP && encap; 93 else 94 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation; 95 96 ops = rcu_dereference(inet6_offloads[proto]); 97 if (likely(ops && ops->callbacks.gso_segment)) { 98 skb_reset_transport_header(skb); 99 segs = ops->callbacks.gso_segment(skb, features); 100 } 101 102 if (IS_ERR_OR_NULL(segs)) 103 goto out; 104 105 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 106 107 for (skb = segs; skb; skb = skb->next) { 108 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 109 if (gso_partial) 110 payload_len = skb_shinfo(skb)->gso_size + 111 SKB_GSO_CB(skb)->data_offset + 112 skb->head - (unsigned char *)(ipv6h + 1); 113 else 114 payload_len = skb->len - nhoff - sizeof(*ipv6h); 115 ipv6h->payload_len = htons(payload_len); 116 skb->network_header = (u8 *)ipv6h - skb->head; 117 118 if (udpfrag) { 119 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 120 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 121 fptr->frag_off = htons(offset); 122 if (skb->next) 123 fptr->frag_off |= htons(IP6_MF); 124 offset += (ntohs(ipv6h->payload_len) - 125 sizeof(struct frag_hdr)); 126 } 127 if (encap) 128 skb_reset_inner_headers(skb); 129 } 130 131 out: 132 return segs; 133 } 134 135 /* Return the total length of all the extension hdrs, following the same 136 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 137 */ 138 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 139 const struct net_offload **opps) 140 { 141 struct ipv6_opt_hdr *opth = (void *)iph; 142 int len = 0, proto, optlen = sizeof(*iph); 143 144 proto = iph->nexthdr; 145 for (;;) { 146 if (proto != NEXTHDR_HOP) { 147 *opps = rcu_dereference(inet6_offloads[proto]); 148 if (unlikely(!(*opps))) 149 break; 150 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 151 break; 152 } 153 opth = (void *)opth + optlen; 154 optlen = ipv6_optlen(opth); 155 len += optlen; 156 proto = opth->nexthdr; 157 } 158 return len; 159 } 160 161 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 162 struct sk_buff *skb) 163 { 164 const struct net_offload *ops; 165 struct sk_buff **pp = NULL; 166 struct sk_buff *p; 167 struct ipv6hdr *iph; 168 unsigned int nlen; 169 unsigned int hlen; 170 unsigned int off; 171 u16 flush = 1; 172 int proto; 173 174 off = skb_gro_offset(skb); 175 hlen = off + sizeof(*iph); 176 iph = skb_gro_header_fast(skb, off); 177 if (skb_gro_header_hard(skb, hlen)) { 178 iph = skb_gro_header_slow(skb, hlen, off); 179 if (unlikely(!iph)) 180 goto out; 181 } 182 183 skb_set_network_header(skb, off); 184 skb_gro_pull(skb, sizeof(*iph)); 185 skb_set_transport_header(skb, skb_gro_offset(skb)); 186 187 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 188 189 rcu_read_lock(); 190 proto = iph->nexthdr; 191 ops = rcu_dereference(inet6_offloads[proto]); 192 if (!ops || !ops->callbacks.gro_receive) { 193 __pskb_pull(skb, skb_gro_offset(skb)); 194 skb_gro_frag0_invalidate(skb); 195 proto = ipv6_gso_pull_exthdrs(skb, proto); 196 skb_gro_pull(skb, -skb_transport_offset(skb)); 197 skb_reset_transport_header(skb); 198 __skb_push(skb, skb_gro_offset(skb)); 199 200 ops = rcu_dereference(inet6_offloads[proto]); 201 if (!ops || !ops->callbacks.gro_receive) 202 goto out_unlock; 203 204 iph = ipv6_hdr(skb); 205 } 206 207 NAPI_GRO_CB(skb)->proto = proto; 208 209 flush--; 210 nlen = skb_network_header_len(skb); 211 212 for (p = *head; p; p = p->next) { 213 const struct ipv6hdr *iph2; 214 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 215 216 if (!NAPI_GRO_CB(p)->same_flow) 217 continue; 218 219 iph2 = (struct ipv6hdr *)(p->data + off); 220 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 221 222 /* All fields must match except length and Traffic Class. 223 * XXX skbs on the gro_list have all been parsed and pulled 224 * already so we don't need to compare nlen 225 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 226 * memcmp() alone below is suffcient, right? 227 */ 228 if ((first_word & htonl(0xF00FFFFF)) || 229 memcmp(&iph->nexthdr, &iph2->nexthdr, 230 nlen - offsetof(struct ipv6hdr, nexthdr))) { 231 NAPI_GRO_CB(p)->same_flow = 0; 232 continue; 233 } 234 /* flush if Traffic Class fields are different */ 235 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 236 NAPI_GRO_CB(p)->flush |= flush; 237 238 /* If the previous IP ID value was based on an atomic 239 * datagram we can overwrite the value and ignore it. 240 */ 241 if (NAPI_GRO_CB(skb)->is_atomic) 242 NAPI_GRO_CB(p)->flush_id = 0; 243 } 244 245 NAPI_GRO_CB(skb)->is_atomic = true; 246 NAPI_GRO_CB(skb)->flush |= flush; 247 248 skb_gro_postpull_rcsum(skb, iph, nlen); 249 250 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); 251 252 out_unlock: 253 rcu_read_unlock(); 254 255 out: 256 skb_gro_flush_final(skb, pp, flush); 257 258 return pp; 259 } 260 261 static struct sk_buff **sit_ip6ip6_gro_receive(struct sk_buff **head, 262 struct sk_buff *skb) 263 { 264 /* Common GRO receive for SIT and IP6IP6 */ 265 266 if (NAPI_GRO_CB(skb)->encap_mark) { 267 NAPI_GRO_CB(skb)->flush = 1; 268 return NULL; 269 } 270 271 NAPI_GRO_CB(skb)->encap_mark = 1; 272 273 return ipv6_gro_receive(head, skb); 274 } 275 276 static struct sk_buff **ip4ip6_gro_receive(struct sk_buff **head, 277 struct sk_buff *skb) 278 { 279 /* Common GRO receive for SIT and IP6IP6 */ 280 281 if (NAPI_GRO_CB(skb)->encap_mark) { 282 NAPI_GRO_CB(skb)->flush = 1; 283 return NULL; 284 } 285 286 NAPI_GRO_CB(skb)->encap_mark = 1; 287 288 return inet_gro_receive(head, skb); 289 } 290 291 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 292 { 293 const struct net_offload *ops; 294 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 295 int err = -ENOSYS; 296 297 if (skb->encapsulation) { 298 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 299 skb_set_inner_network_header(skb, nhoff); 300 } 301 302 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 303 304 rcu_read_lock(); 305 306 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 307 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 308 goto out_unlock; 309 310 err = ops->callbacks.gro_complete(skb, nhoff); 311 312 out_unlock: 313 rcu_read_unlock(); 314 315 return err; 316 } 317 318 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 319 { 320 skb->encapsulation = 1; 321 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 322 return ipv6_gro_complete(skb, nhoff); 323 } 324 325 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 326 { 327 skb->encapsulation = 1; 328 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 329 return ipv6_gro_complete(skb, nhoff); 330 } 331 332 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 333 { 334 skb->encapsulation = 1; 335 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 336 return inet_gro_complete(skb, nhoff); 337 } 338 339 static struct packet_offload ipv6_packet_offload __read_mostly = { 340 .type = cpu_to_be16(ETH_P_IPV6), 341 .callbacks = { 342 .gso_segment = ipv6_gso_segment, 343 .gro_receive = ipv6_gro_receive, 344 .gro_complete = ipv6_gro_complete, 345 }, 346 }; 347 348 static const struct net_offload sit_offload = { 349 .callbacks = { 350 .gso_segment = ipv6_gso_segment, 351 .gro_receive = sit_ip6ip6_gro_receive, 352 .gro_complete = sit_gro_complete, 353 }, 354 }; 355 356 static const struct net_offload ip4ip6_offload = { 357 .callbacks = { 358 .gso_segment = inet_gso_segment, 359 .gro_receive = ip4ip6_gro_receive, 360 .gro_complete = ip4ip6_gro_complete, 361 }, 362 }; 363 364 static const struct net_offload ip6ip6_offload = { 365 .callbacks = { 366 .gso_segment = ipv6_gso_segment, 367 .gro_receive = sit_ip6ip6_gro_receive, 368 .gro_complete = ip6ip6_gro_complete, 369 }, 370 }; 371 static int __init ipv6_offload_init(void) 372 { 373 374 if (tcpv6_offload_init() < 0) 375 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 376 if (ipv6_exthdrs_offload_init() < 0) 377 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 378 379 dev_add_offload(&ipv6_packet_offload); 380 381 inet_add_offload(&sit_offload, IPPROTO_IPV6); 382 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 383 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 384 385 return 0; 386 } 387 388 fs_initcall(ipv6_offload_init); 389