1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IPV6 GSO/GRO offload support 4 * Linux INET6 implementation 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/socket.h> 9 #include <linux/netdevice.h> 10 #include <linux/skbuff.h> 11 #include <linux/printk.h> 12 13 #include <net/protocol.h> 14 #include <net/ipv6.h> 15 #include <net/inet_common.h> 16 #include <net/tcp.h> 17 #include <net/udp.h> 18 #include <net/gro.h> 19 #include <net/gso.h> 20 21 #include "ip6_offload.h" 22 23 /* All GRO functions are always builtin, except UDP over ipv6, which lays in 24 * ipv6 module, as it depends on UDPv6 lookup function, so we need special care 25 * when ipv6 is built as a module 26 */ 27 #if IS_BUILTIN(CONFIG_IPV6) 28 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__) 29 #else 30 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__) 31 #endif 32 33 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \ 34 ({ \ 35 unlikely(gro_recursion_inc_test(skb)) ? \ 36 NAPI_GRO_CB(skb)->flush |= 1, NULL : \ 37 INDIRECT_CALL_L4(cb, f2, f1, head, skb); \ 38 }) 39 40 static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto) 41 { 42 const struct net_offload *ops = NULL; 43 struct ipv6_opt_hdr *opth; 44 45 for (;;) { 46 int len; 47 48 ops = rcu_dereference(inet6_offloads[proto]); 49 50 if (unlikely(!ops)) 51 break; 52 53 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 54 break; 55 56 opth = skb_gro_header(skb, off + sizeof(*opth), off); 57 if (unlikely(!opth)) 58 break; 59 60 len = ipv6_optlen(opth); 61 62 opth = skb_gro_header(skb, off + len, off); 63 if (unlikely(!opth)) 64 break; 65 proto = opth->nexthdr; 66 67 off += len; 68 } 69 70 skb_gro_pull(skb, off - skb_network_offset(skb)); 71 return proto; 72 } 73 74 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 75 { 76 const struct net_offload *ops = NULL; 77 78 for (;;) { 79 struct ipv6_opt_hdr *opth; 80 int len; 81 82 if (proto != NEXTHDR_HOP) { 83 ops = rcu_dereference(inet6_offloads[proto]); 84 85 if (unlikely(!ops)) 86 break; 87 88 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 89 break; 90 } 91 92 if (unlikely(!pskb_may_pull(skb, 8))) 93 break; 94 95 opth = (void *)skb->data; 96 len = ipv6_optlen(opth); 97 98 if (unlikely(!pskb_may_pull(skb, len))) 99 break; 100 101 opth = (void *)skb->data; 102 proto = opth->nexthdr; 103 __skb_pull(skb, len); 104 } 105 106 return proto; 107 } 108 109 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 110 netdev_features_t features) 111 { 112 struct sk_buff *segs = ERR_PTR(-EINVAL); 113 struct ipv6hdr *ipv6h; 114 const struct net_offload *ops; 115 int proto, err; 116 struct frag_hdr *fptr; 117 unsigned int payload_len; 118 u8 *prevhdr; 119 int offset = 0; 120 bool encap, udpfrag; 121 int nhoff; 122 bool gso_partial; 123 124 skb_reset_network_header(skb); 125 err = ipv6_hopopt_jumbo_remove(skb); 126 if (err) 127 return ERR_PTR(err); 128 nhoff = skb_network_header(skb) - skb_mac_header(skb); 129 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 130 goto out; 131 132 encap = SKB_GSO_CB(skb)->encap_level > 0; 133 if (encap) 134 features &= skb->dev->hw_enc_features; 135 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 136 137 ipv6h = ipv6_hdr(skb); 138 __skb_pull(skb, sizeof(*ipv6h)); 139 segs = ERR_PTR(-EPROTONOSUPPORT); 140 141 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 142 143 if (skb->encapsulation && 144 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 145 udpfrag = proto == IPPROTO_UDP && encap && 146 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 147 else 148 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation && 149 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 150 151 ops = rcu_dereference(inet6_offloads[proto]); 152 if (likely(ops && ops->callbacks.gso_segment)) { 153 skb_reset_transport_header(skb); 154 segs = ops->callbacks.gso_segment(skb, features); 155 if (!segs) 156 skb->network_header = skb_mac_header(skb) + nhoff - skb->head; 157 } 158 159 if (IS_ERR_OR_NULL(segs)) 160 goto out; 161 162 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 163 164 for (skb = segs; skb; skb = skb->next) { 165 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 166 if (gso_partial && skb_is_gso(skb)) 167 payload_len = skb_shinfo(skb)->gso_size + 168 SKB_GSO_CB(skb)->data_offset + 169 skb->head - (unsigned char *)(ipv6h + 1); 170 else 171 payload_len = skb->len - nhoff - sizeof(*ipv6h); 172 ipv6h->payload_len = htons(payload_len); 173 skb->network_header = (u8 *)ipv6h - skb->head; 174 skb_reset_mac_len(skb); 175 176 if (udpfrag) { 177 int err = ip6_find_1stfragopt(skb, &prevhdr); 178 if (err < 0) { 179 kfree_skb_list(segs); 180 return ERR_PTR(err); 181 } 182 fptr = (struct frag_hdr *)((u8 *)ipv6h + err); 183 fptr->frag_off = htons(offset); 184 if (skb->next) 185 fptr->frag_off |= htons(IP6_MF); 186 offset += (ntohs(ipv6h->payload_len) - 187 sizeof(struct frag_hdr)); 188 } 189 if (encap) 190 skb_reset_inner_headers(skb); 191 } 192 193 out: 194 return segs; 195 } 196 197 /* Return the total length of all the extension hdrs, following the same 198 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 199 */ 200 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 201 const struct net_offload **opps) 202 { 203 struct ipv6_opt_hdr *opth = (void *)iph; 204 int len = 0, proto, optlen = sizeof(*iph); 205 206 proto = iph->nexthdr; 207 for (;;) { 208 if (proto != NEXTHDR_HOP) { 209 *opps = rcu_dereference(inet6_offloads[proto]); 210 if (unlikely(!(*opps))) 211 break; 212 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 213 break; 214 } 215 opth = (void *)opth + optlen; 216 optlen = ipv6_optlen(opth); 217 len += optlen; 218 proto = opth->nexthdr; 219 } 220 return len; 221 } 222 223 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, 224 struct sk_buff *skb) 225 { 226 const struct net_offload *ops; 227 struct sk_buff *pp = NULL; 228 struct sk_buff *p; 229 struct ipv6hdr *iph; 230 unsigned int nlen; 231 unsigned int hlen; 232 unsigned int off; 233 u16 flush = 1; 234 int proto; 235 236 off = skb_gro_offset(skb); 237 hlen = off + sizeof(*iph); 238 iph = skb_gro_header(skb, hlen, off); 239 if (unlikely(!iph)) 240 goto out; 241 242 skb_set_network_header(skb, off); 243 NAPI_GRO_CB(skb)->inner_network_offset = off; 244 245 flush += ntohs(iph->payload_len) != skb->len - hlen; 246 247 proto = iph->nexthdr; 248 ops = rcu_dereference(inet6_offloads[proto]); 249 if (!ops || !ops->callbacks.gro_receive) { 250 proto = ipv6_gro_pull_exthdrs(skb, hlen, proto); 251 252 ops = rcu_dereference(inet6_offloads[proto]); 253 if (!ops || !ops->callbacks.gro_receive) 254 goto out; 255 256 iph = skb_gro_network_header(skb); 257 } else { 258 skb_gro_pull(skb, sizeof(*iph)); 259 } 260 261 skb_set_transport_header(skb, skb_gro_offset(skb)); 262 263 NAPI_GRO_CB(skb)->proto = proto; 264 265 flush--; 266 nlen = skb_network_header_len(skb); 267 268 list_for_each_entry(p, head, list) { 269 const struct ipv6hdr *iph2; 270 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 271 272 if (!NAPI_GRO_CB(p)->same_flow) 273 continue; 274 275 iph2 = (struct ipv6hdr *)(p->data + off); 276 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 277 278 /* All fields must match except length and Traffic Class. 279 * XXX skbs on the gro_list have all been parsed and pulled 280 * already so we don't need to compare nlen 281 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 282 * memcmp() alone below is sufficient, right? 283 */ 284 if ((first_word & htonl(0xF00FFFFF)) || 285 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) || 286 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) || 287 iph->nexthdr != iph2->nexthdr) { 288 not_same_flow: 289 NAPI_GRO_CB(p)->same_flow = 0; 290 continue; 291 } 292 if (unlikely(nlen > sizeof(struct ipv6hdr))) { 293 if (memcmp(iph + 1, iph2 + 1, 294 nlen - sizeof(struct ipv6hdr))) 295 goto not_same_flow; 296 } 297 /* flush if Traffic Class fields are different */ 298 NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) | 299 (__force __be32)(iph->hop_limit ^ iph2->hop_limit)); 300 NAPI_GRO_CB(p)->flush |= flush; 301 302 /* If the previous IP ID value was based on an atomic 303 * datagram we can overwrite the value and ignore it. 304 */ 305 if (NAPI_GRO_CB(skb)->is_atomic) 306 NAPI_GRO_CB(p)->flush_id = 0; 307 } 308 309 NAPI_GRO_CB(skb)->is_atomic = true; 310 NAPI_GRO_CB(skb)->flush |= flush; 311 312 skb_gro_postpull_rcsum(skb, iph, nlen); 313 314 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive, 315 ops->callbacks.gro_receive, head, skb); 316 317 out: 318 skb_gro_flush_final(skb, pp, flush); 319 320 return pp; 321 } 322 323 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head, 324 struct sk_buff *skb) 325 { 326 /* Common GRO receive for SIT and IP6IP6 */ 327 328 if (NAPI_GRO_CB(skb)->encap_mark) { 329 NAPI_GRO_CB(skb)->flush = 1; 330 return NULL; 331 } 332 333 NAPI_GRO_CB(skb)->encap_mark = 1; 334 335 return ipv6_gro_receive(head, skb); 336 } 337 338 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, 339 struct sk_buff *skb) 340 { 341 /* Common GRO receive for SIT and IP6IP6 */ 342 343 if (NAPI_GRO_CB(skb)->encap_mark) { 344 NAPI_GRO_CB(skb)->flush = 1; 345 return NULL; 346 } 347 348 NAPI_GRO_CB(skb)->encap_mark = 1; 349 350 return inet_gro_receive(head, skb); 351 } 352 353 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 354 { 355 const struct net_offload *ops; 356 struct ipv6hdr *iph; 357 int err = -ENOSYS; 358 u32 payload_len; 359 360 if (skb->encapsulation) { 361 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 362 skb_set_inner_network_header(skb, nhoff); 363 } 364 365 payload_len = skb->len - nhoff - sizeof(*iph); 366 if (unlikely(payload_len > IPV6_MAXPLEN)) { 367 struct hop_jumbo_hdr *hop_jumbo; 368 int hoplen = sizeof(*hop_jumbo); 369 370 /* Move network header left */ 371 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb), 372 skb->transport_header - skb->mac_header); 373 skb->data -= hoplen; 374 skb->len += hoplen; 375 skb->mac_header -= hoplen; 376 skb->network_header -= hoplen; 377 iph = (struct ipv6hdr *)(skb->data + nhoff); 378 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1); 379 380 /* Build hop-by-hop options */ 381 hop_jumbo->nexthdr = iph->nexthdr; 382 hop_jumbo->hdrlen = 0; 383 hop_jumbo->tlv_type = IPV6_TLV_JUMBO; 384 hop_jumbo->tlv_len = 4; 385 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen); 386 387 iph->nexthdr = NEXTHDR_HOP; 388 iph->payload_len = 0; 389 } else { 390 iph = (struct ipv6hdr *)(skb->data + nhoff); 391 iph->payload_len = htons(payload_len); 392 } 393 394 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 395 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 396 goto out; 397 398 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete, 399 udp6_gro_complete, skb, nhoff); 400 401 out: 402 return err; 403 } 404 405 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 406 { 407 skb->encapsulation = 1; 408 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 409 return ipv6_gro_complete(skb, nhoff); 410 } 411 412 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 413 { 414 skb->encapsulation = 1; 415 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 416 return ipv6_gro_complete(skb, nhoff); 417 } 418 419 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 420 { 421 skb->encapsulation = 1; 422 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 423 return inet_gro_complete(skb, nhoff); 424 } 425 426 static struct packet_offload ipv6_packet_offload __read_mostly = { 427 .type = cpu_to_be16(ETH_P_IPV6), 428 .callbacks = { 429 .gso_segment = ipv6_gso_segment, 430 .gro_receive = ipv6_gro_receive, 431 .gro_complete = ipv6_gro_complete, 432 }, 433 }; 434 435 static struct sk_buff *sit_gso_segment(struct sk_buff *skb, 436 netdev_features_t features) 437 { 438 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4)) 439 return ERR_PTR(-EINVAL); 440 441 return ipv6_gso_segment(skb, features); 442 } 443 444 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb, 445 netdev_features_t features) 446 { 447 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 448 return ERR_PTR(-EINVAL); 449 450 return inet_gso_segment(skb, features); 451 } 452 453 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb, 454 netdev_features_t features) 455 { 456 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 457 return ERR_PTR(-EINVAL); 458 459 return ipv6_gso_segment(skb, features); 460 } 461 462 static const struct net_offload sit_offload = { 463 .callbacks = { 464 .gso_segment = sit_gso_segment, 465 .gro_receive = sit_ip6ip6_gro_receive, 466 .gro_complete = sit_gro_complete, 467 }, 468 }; 469 470 static const struct net_offload ip4ip6_offload = { 471 .callbacks = { 472 .gso_segment = ip4ip6_gso_segment, 473 .gro_receive = ip4ip6_gro_receive, 474 .gro_complete = ip4ip6_gro_complete, 475 }, 476 }; 477 478 static const struct net_offload ip6ip6_offload = { 479 .callbacks = { 480 .gso_segment = ip6ip6_gso_segment, 481 .gro_receive = sit_ip6ip6_gro_receive, 482 .gro_complete = ip6ip6_gro_complete, 483 }, 484 }; 485 static int __init ipv6_offload_init(void) 486 { 487 488 if (tcpv6_offload_init() < 0) 489 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 490 if (ipv6_exthdrs_offload_init() < 0) 491 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 492 493 dev_add_offload(&ipv6_packet_offload); 494 495 inet_add_offload(&sit_offload, IPPROTO_IPV6); 496 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 497 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 498 499 return 0; 500 } 501 502 fs_initcall(ipv6_offload_init); 503