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_gro_receive_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 ops = rcu_dereference(inet6_offloads[proto]); 83 84 if (unlikely(!ops)) 85 break; 86 87 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 88 break; 89 90 if (unlikely(!pskb_may_pull(skb, 8))) 91 break; 92 93 opth = (void *)skb->data; 94 len = ipv6_optlen(opth); 95 96 if (unlikely(!pskb_may_pull(skb, len))) 97 break; 98 99 opth = (void *)skb->data; 100 proto = opth->nexthdr; 101 __skb_pull(skb, len); 102 } 103 104 return proto; 105 } 106 107 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 108 netdev_features_t features) 109 { 110 struct sk_buff *segs = ERR_PTR(-EINVAL); 111 struct ipv6hdr *ipv6h; 112 const struct net_offload *ops; 113 int proto, err; 114 struct frag_hdr *fptr; 115 unsigned int payload_len; 116 u8 *prevhdr; 117 int offset = 0; 118 bool encap, udpfrag; 119 int nhoff; 120 bool gso_partial; 121 122 skb_reset_network_header(skb); 123 err = ipv6_hopopt_jumbo_remove(skb); 124 if (err) 125 return ERR_PTR(err); 126 nhoff = skb_network_header(skb) - skb_mac_header(skb); 127 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 128 goto out; 129 130 encap = SKB_GSO_CB(skb)->encap_level > 0; 131 if (encap) 132 features &= skb->dev->hw_enc_features; 133 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 134 135 ipv6h = ipv6_hdr(skb); 136 __skb_pull(skb, sizeof(*ipv6h)); 137 segs = ERR_PTR(-EPROTONOSUPPORT); 138 139 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 140 141 if (skb->encapsulation && 142 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 143 udpfrag = proto == IPPROTO_UDP && encap && 144 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 145 else 146 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation && 147 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 148 149 ops = rcu_dereference(inet6_offloads[proto]); 150 if (likely(ops && ops->callbacks.gso_segment)) { 151 skb_reset_transport_header(skb); 152 segs = ops->callbacks.gso_segment(skb, features); 153 if (!segs) 154 skb->network_header = skb_mac_header(skb) + nhoff - skb->head; 155 } 156 157 if (IS_ERR_OR_NULL(segs)) 158 goto out; 159 160 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 161 162 for (skb = segs; skb; skb = skb->next) { 163 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 164 if (gso_partial && skb_is_gso(skb)) 165 payload_len = skb_shinfo(skb)->gso_size + 166 SKB_GSO_CB(skb)->data_offset + 167 skb->head - (unsigned char *)(ipv6h + 1); 168 else 169 payload_len = skb->len - nhoff - sizeof(*ipv6h); 170 ipv6h->payload_len = htons(payload_len); 171 skb->network_header = (u8 *)ipv6h - skb->head; 172 skb_reset_mac_len(skb); 173 174 if (udpfrag) { 175 int err = ip6_find_1stfragopt(skb, &prevhdr); 176 if (err < 0) { 177 kfree_skb_list(segs); 178 return ERR_PTR(err); 179 } 180 fptr = (struct frag_hdr *)((u8 *)ipv6h + err); 181 fptr->frag_off = htons(offset); 182 if (skb->next) 183 fptr->frag_off |= htons(IP6_MF); 184 offset += (ntohs(ipv6h->payload_len) - 185 sizeof(struct frag_hdr)); 186 } 187 if (encap) 188 skb_reset_inner_headers(skb); 189 } 190 191 out: 192 return segs; 193 } 194 195 /* Return the total length of all the extension hdrs, following the same 196 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 197 */ 198 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 199 const struct net_offload **opps) 200 { 201 struct ipv6_opt_hdr *opth = (void *)iph; 202 int len = 0, proto, optlen = sizeof(*iph); 203 204 proto = iph->nexthdr; 205 for (;;) { 206 *opps = rcu_dereference(inet6_offloads[proto]); 207 if (unlikely(!(*opps))) 208 break; 209 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 210 break; 211 212 opth = (void *)opth + optlen; 213 optlen = ipv6_optlen(opth); 214 len += optlen; 215 proto = opth->nexthdr; 216 } 217 return len; 218 } 219 220 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, 221 struct sk_buff *skb) 222 { 223 const struct net_offload *ops; 224 struct sk_buff *pp = NULL; 225 struct sk_buff *p; 226 struct ipv6hdr *iph; 227 unsigned int nlen; 228 unsigned int hlen; 229 unsigned int off; 230 u16 flush = 1; 231 int proto; 232 233 off = skb_gro_offset(skb); 234 hlen = off + sizeof(*iph); 235 iph = skb_gro_header(skb, hlen, off); 236 if (unlikely(!iph)) 237 goto out; 238 239 NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = off; 240 241 flush += ntohs(iph->payload_len) != skb->len - hlen; 242 243 proto = iph->nexthdr; 244 ops = rcu_dereference(inet6_offloads[proto]); 245 if (!ops || !ops->callbacks.gro_receive) { 246 proto = ipv6_gro_pull_exthdrs(skb, hlen, proto); 247 248 ops = rcu_dereference(inet6_offloads[proto]); 249 if (!ops || !ops->callbacks.gro_receive) 250 goto out; 251 252 iph = skb_gro_network_header(skb); 253 } else { 254 skb_gro_pull(skb, sizeof(*iph)); 255 } 256 257 skb_set_transport_header(skb, skb_gro_offset(skb)); 258 259 NAPI_GRO_CB(skb)->proto = proto; 260 261 flush--; 262 nlen = skb_gro_offset(skb) - off; 263 264 list_for_each_entry(p, head, list) { 265 const struct ipv6hdr *iph2; 266 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 267 268 if (!NAPI_GRO_CB(p)->same_flow) 269 continue; 270 271 iph2 = (struct ipv6hdr *)(p->data + off); 272 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 273 274 /* All fields must match except length and Traffic Class. 275 * XXX skbs on the gro_list have all been parsed and pulled 276 * already so we don't need to compare nlen 277 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 278 * memcmp() alone below is sufficient, right? 279 */ 280 if ((first_word & htonl(0xF00FFFFF)) || 281 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) || 282 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) || 283 iph->nexthdr != iph2->nexthdr) { 284 not_same_flow: 285 NAPI_GRO_CB(p)->same_flow = 0; 286 continue; 287 } 288 if (unlikely(nlen > sizeof(struct ipv6hdr))) { 289 if (memcmp(iph + 1, iph2 + 1, 290 nlen - sizeof(struct ipv6hdr))) 291 goto not_same_flow; 292 } 293 } 294 295 NAPI_GRO_CB(skb)->flush |= flush; 296 297 skb_gro_postpull_rcsum(skb, iph, nlen); 298 299 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive, 300 ops->callbacks.gro_receive, head, skb); 301 302 out: 303 skb_gro_flush_final(skb, pp, flush); 304 305 return pp; 306 } 307 308 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head, 309 struct sk_buff *skb) 310 { 311 /* Common GRO receive for SIT and IP6IP6 */ 312 313 if (NAPI_GRO_CB(skb)->encap_mark) { 314 NAPI_GRO_CB(skb)->flush = 1; 315 return NULL; 316 } 317 318 NAPI_GRO_CB(skb)->encap_mark = 1; 319 320 return ipv6_gro_receive(head, skb); 321 } 322 323 static struct sk_buff *ip4ip6_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 inet_gro_receive(head, skb); 336 } 337 338 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 339 { 340 const struct net_offload *ops; 341 struct ipv6hdr *iph; 342 int err = -ENOSYS; 343 u32 payload_len; 344 345 if (skb->encapsulation) { 346 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 347 skb_set_inner_network_header(skb, nhoff); 348 } 349 350 payload_len = skb->len - nhoff - sizeof(*iph); 351 if (unlikely(payload_len > IPV6_MAXPLEN)) { 352 struct hop_jumbo_hdr *hop_jumbo; 353 int hoplen = sizeof(*hop_jumbo); 354 355 /* Move network header left */ 356 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb), 357 skb->transport_header - skb->mac_header); 358 skb->data -= hoplen; 359 skb->len += hoplen; 360 skb->mac_header -= hoplen; 361 skb->network_header -= hoplen; 362 iph = (struct ipv6hdr *)(skb->data + nhoff); 363 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1); 364 365 /* Build hop-by-hop options */ 366 hop_jumbo->nexthdr = iph->nexthdr; 367 hop_jumbo->hdrlen = 0; 368 hop_jumbo->tlv_type = IPV6_TLV_JUMBO; 369 hop_jumbo->tlv_len = 4; 370 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen); 371 372 iph->nexthdr = NEXTHDR_HOP; 373 iph->payload_len = 0; 374 } else { 375 iph = (struct ipv6hdr *)(skb->data + nhoff); 376 iph->payload_len = htons(payload_len); 377 } 378 379 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 380 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 381 goto out; 382 383 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete, 384 udp6_gro_complete, skb, nhoff); 385 386 out: 387 return err; 388 } 389 390 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 391 { 392 skb->encapsulation = 1; 393 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 394 return ipv6_gro_complete(skb, nhoff); 395 } 396 397 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 398 { 399 skb->encapsulation = 1; 400 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 401 return ipv6_gro_complete(skb, nhoff); 402 } 403 404 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 405 { 406 skb->encapsulation = 1; 407 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 408 return inet_gro_complete(skb, nhoff); 409 } 410 411 412 static struct sk_buff *sit_gso_segment(struct sk_buff *skb, 413 netdev_features_t features) 414 { 415 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4)) 416 return ERR_PTR(-EINVAL); 417 418 return ipv6_gso_segment(skb, features); 419 } 420 421 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb, 422 netdev_features_t features) 423 { 424 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 425 return ERR_PTR(-EINVAL); 426 427 return inet_gso_segment(skb, features); 428 } 429 430 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb, 431 netdev_features_t features) 432 { 433 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 434 return ERR_PTR(-EINVAL); 435 436 return ipv6_gso_segment(skb, features); 437 } 438 439 static const struct net_offload sit_offload = { 440 .callbacks = { 441 .gso_segment = sit_gso_segment, 442 .gro_receive = sit_ip6ip6_gro_receive, 443 .gro_complete = sit_gro_complete, 444 }, 445 }; 446 447 static const struct net_offload ip4ip6_offload = { 448 .callbacks = { 449 .gso_segment = ip4ip6_gso_segment, 450 .gro_receive = ip4ip6_gro_receive, 451 .gro_complete = ip4ip6_gro_complete, 452 }, 453 }; 454 455 static const struct net_offload ip6ip6_offload = { 456 .callbacks = { 457 .gso_segment = ip6ip6_gso_segment, 458 .gro_receive = sit_ip6ip6_gro_receive, 459 .gro_complete = ip6ip6_gro_complete, 460 }, 461 }; 462 static int __init ipv6_offload_init(void) 463 { 464 465 if (tcpv6_offload_init() < 0) 466 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 467 if (ipv6_exthdrs_offload_init() < 0) 468 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 469 470 net_hotdata.ipv6_packet_offload = (struct packet_offload) { 471 .type = cpu_to_be16(ETH_P_IPV6), 472 .callbacks = { 473 .gso_segment = ipv6_gso_segment, 474 .gro_receive = ipv6_gro_receive, 475 .gro_complete = ipv6_gro_complete, 476 }, 477 }; 478 dev_add_offload(&net_hotdata.ipv6_packet_offload); 479 480 inet_add_offload(&sit_offload, IPPROTO_IPV6); 481 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 482 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 483 484 return 0; 485 } 486 487 fs_initcall(ipv6_offload_init); 488