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 20 #include "ip6_offload.h" 21 22 /* All GRO functions are always builtin, except UDP over ipv6, which lays in 23 * ipv6 module, as it depends on UDPv6 lookup function, so we need special care 24 * when ipv6 is built as a module 25 */ 26 #if IS_BUILTIN(CONFIG_IPV6) 27 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__) 28 #else 29 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__) 30 #endif 31 32 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \ 33 ({ \ 34 unlikely(gro_recursion_inc_test(skb)) ? \ 35 NAPI_GRO_CB(skb)->flush |= 1, NULL : \ 36 INDIRECT_CALL_L4(cb, f2, f1, head, skb); \ 37 }) 38 39 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 40 { 41 const struct net_offload *ops = NULL; 42 43 for (;;) { 44 struct ipv6_opt_hdr *opth; 45 int len; 46 47 if (proto != NEXTHDR_HOP) { 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 57 if (unlikely(!pskb_may_pull(skb, 8))) 58 break; 59 60 opth = (void *)skb->data; 61 len = ipv6_optlen(opth); 62 63 if (unlikely(!pskb_may_pull(skb, len))) 64 break; 65 66 opth = (void *)skb->data; 67 proto = opth->nexthdr; 68 __skb_pull(skb, len); 69 } 70 71 return proto; 72 } 73 74 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 75 netdev_features_t features) 76 { 77 struct sk_buff *segs = ERR_PTR(-EINVAL); 78 struct ipv6hdr *ipv6h; 79 const struct net_offload *ops; 80 int proto, err; 81 struct frag_hdr *fptr; 82 unsigned int payload_len; 83 u8 *prevhdr; 84 int offset = 0; 85 bool encap, udpfrag; 86 int nhoff; 87 bool gso_partial; 88 89 skb_reset_network_header(skb); 90 err = ipv6_hopopt_jumbo_remove(skb); 91 if (err) 92 return ERR_PTR(err); 93 nhoff = skb_network_header(skb) - skb_mac_header(skb); 94 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 95 goto out; 96 97 encap = SKB_GSO_CB(skb)->encap_level > 0; 98 if (encap) 99 features &= skb->dev->hw_enc_features; 100 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 101 102 ipv6h = ipv6_hdr(skb); 103 __skb_pull(skb, sizeof(*ipv6h)); 104 segs = ERR_PTR(-EPROTONOSUPPORT); 105 106 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 107 108 if (skb->encapsulation && 109 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 110 udpfrag = proto == IPPROTO_UDP && encap && 111 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 112 else 113 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation && 114 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 115 116 ops = rcu_dereference(inet6_offloads[proto]); 117 if (likely(ops && ops->callbacks.gso_segment)) { 118 skb_reset_transport_header(skb); 119 segs = ops->callbacks.gso_segment(skb, features); 120 if (!segs) 121 skb->network_header = skb_mac_header(skb) + nhoff - skb->head; 122 } 123 124 if (IS_ERR_OR_NULL(segs)) 125 goto out; 126 127 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 128 129 for (skb = segs; skb; skb = skb->next) { 130 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 131 if (gso_partial && skb_is_gso(skb)) 132 payload_len = skb_shinfo(skb)->gso_size + 133 SKB_GSO_CB(skb)->data_offset + 134 skb->head - (unsigned char *)(ipv6h + 1); 135 else 136 payload_len = skb->len - nhoff - sizeof(*ipv6h); 137 ipv6h->payload_len = htons(payload_len); 138 skb->network_header = (u8 *)ipv6h - skb->head; 139 skb_reset_mac_len(skb); 140 141 if (udpfrag) { 142 int err = ip6_find_1stfragopt(skb, &prevhdr); 143 if (err < 0) { 144 kfree_skb_list(segs); 145 return ERR_PTR(err); 146 } 147 fptr = (struct frag_hdr *)((u8 *)ipv6h + err); 148 fptr->frag_off = htons(offset); 149 if (skb->next) 150 fptr->frag_off |= htons(IP6_MF); 151 offset += (ntohs(ipv6h->payload_len) - 152 sizeof(struct frag_hdr)); 153 } 154 if (encap) 155 skb_reset_inner_headers(skb); 156 } 157 158 out: 159 return segs; 160 } 161 162 /* Return the total length of all the extension hdrs, following the same 163 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 164 */ 165 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 166 const struct net_offload **opps) 167 { 168 struct ipv6_opt_hdr *opth = (void *)iph; 169 int len = 0, proto, optlen = sizeof(*iph); 170 171 proto = iph->nexthdr; 172 for (;;) { 173 if (proto != NEXTHDR_HOP) { 174 *opps = rcu_dereference(inet6_offloads[proto]); 175 if (unlikely(!(*opps))) 176 break; 177 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 178 break; 179 } 180 opth = (void *)opth + optlen; 181 optlen = ipv6_optlen(opth); 182 len += optlen; 183 proto = opth->nexthdr; 184 } 185 return len; 186 } 187 188 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, 189 struct sk_buff *skb) 190 { 191 const struct net_offload *ops; 192 struct sk_buff *pp = NULL; 193 struct sk_buff *p; 194 struct ipv6hdr *iph; 195 unsigned int nlen; 196 unsigned int hlen; 197 unsigned int off; 198 u16 flush = 1; 199 int proto; 200 201 off = skb_gro_offset(skb); 202 hlen = off + sizeof(*iph); 203 iph = skb_gro_header(skb, hlen, off); 204 if (unlikely(!iph)) 205 goto out; 206 207 skb_set_network_header(skb, off); 208 skb_gro_pull(skb, sizeof(*iph)); 209 skb_set_transport_header(skb, skb_gro_offset(skb)); 210 211 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 212 213 proto = iph->nexthdr; 214 ops = rcu_dereference(inet6_offloads[proto]); 215 if (!ops || !ops->callbacks.gro_receive) { 216 pskb_pull(skb, skb_gro_offset(skb)); 217 skb_gro_frag0_invalidate(skb); 218 proto = ipv6_gso_pull_exthdrs(skb, proto); 219 skb_gro_pull(skb, -skb_transport_offset(skb)); 220 skb_reset_transport_header(skb); 221 __skb_push(skb, skb_gro_offset(skb)); 222 223 ops = rcu_dereference(inet6_offloads[proto]); 224 if (!ops || !ops->callbacks.gro_receive) 225 goto out; 226 227 iph = ipv6_hdr(skb); 228 } 229 230 NAPI_GRO_CB(skb)->proto = proto; 231 232 flush--; 233 nlen = skb_network_header_len(skb); 234 235 list_for_each_entry(p, head, list) { 236 const struct ipv6hdr *iph2; 237 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 238 239 if (!NAPI_GRO_CB(p)->same_flow) 240 continue; 241 242 iph2 = (struct ipv6hdr *)(p->data + off); 243 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 244 245 /* All fields must match except length and Traffic Class. 246 * XXX skbs on the gro_list have all been parsed and pulled 247 * already so we don't need to compare nlen 248 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 249 * memcmp() alone below is sufficient, right? 250 */ 251 if ((first_word & htonl(0xF00FFFFF)) || 252 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) || 253 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) || 254 iph->nexthdr != iph2->nexthdr) { 255 not_same_flow: 256 NAPI_GRO_CB(p)->same_flow = 0; 257 continue; 258 } 259 if (unlikely(nlen > sizeof(struct ipv6hdr))) { 260 if (memcmp(iph + 1, iph2 + 1, 261 nlen - sizeof(struct ipv6hdr))) 262 goto not_same_flow; 263 } 264 /* flush if Traffic Class fields are different */ 265 NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) | 266 (__force __be32)(iph->hop_limit ^ iph2->hop_limit)); 267 NAPI_GRO_CB(p)->flush |= flush; 268 269 /* If the previous IP ID value was based on an atomic 270 * datagram we can overwrite the value and ignore it. 271 */ 272 if (NAPI_GRO_CB(skb)->is_atomic) 273 NAPI_GRO_CB(p)->flush_id = 0; 274 } 275 276 NAPI_GRO_CB(skb)->is_atomic = true; 277 NAPI_GRO_CB(skb)->flush |= flush; 278 279 skb_gro_postpull_rcsum(skb, iph, nlen); 280 281 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive, 282 ops->callbacks.gro_receive, head, skb); 283 284 out: 285 skb_gro_flush_final(skb, pp, flush); 286 287 return pp; 288 } 289 290 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head, 291 struct sk_buff *skb) 292 { 293 /* Common GRO receive for SIT and IP6IP6 */ 294 295 if (NAPI_GRO_CB(skb)->encap_mark) { 296 NAPI_GRO_CB(skb)->flush = 1; 297 return NULL; 298 } 299 300 NAPI_GRO_CB(skb)->encap_mark = 1; 301 302 return ipv6_gro_receive(head, skb); 303 } 304 305 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, 306 struct sk_buff *skb) 307 { 308 /* Common GRO receive for SIT and IP6IP6 */ 309 310 if (NAPI_GRO_CB(skb)->encap_mark) { 311 NAPI_GRO_CB(skb)->flush = 1; 312 return NULL; 313 } 314 315 NAPI_GRO_CB(skb)->encap_mark = 1; 316 317 return inet_gro_receive(head, skb); 318 } 319 320 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 321 { 322 const struct net_offload *ops; 323 struct ipv6hdr *iph; 324 int err = -ENOSYS; 325 u32 payload_len; 326 327 if (skb->encapsulation) { 328 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 329 skb_set_inner_network_header(skb, nhoff); 330 } 331 332 payload_len = skb->len - nhoff - sizeof(*iph); 333 if (unlikely(payload_len > IPV6_MAXPLEN)) { 334 struct hop_jumbo_hdr *hop_jumbo; 335 int hoplen = sizeof(*hop_jumbo); 336 337 /* Move network header left */ 338 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb), 339 skb->transport_header - skb->mac_header); 340 skb->data -= hoplen; 341 skb->len += hoplen; 342 skb->mac_header -= hoplen; 343 skb->network_header -= hoplen; 344 iph = (struct ipv6hdr *)(skb->data + nhoff); 345 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1); 346 347 /* Build hop-by-hop options */ 348 hop_jumbo->nexthdr = iph->nexthdr; 349 hop_jumbo->hdrlen = 0; 350 hop_jumbo->tlv_type = IPV6_TLV_JUMBO; 351 hop_jumbo->tlv_len = 4; 352 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen); 353 354 iph->nexthdr = NEXTHDR_HOP; 355 iph->payload_len = 0; 356 } else { 357 iph = (struct ipv6hdr *)(skb->data + nhoff); 358 iph->payload_len = htons(payload_len); 359 } 360 361 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 362 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 363 goto out; 364 365 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete, 366 udp6_gro_complete, skb, nhoff); 367 368 out: 369 return err; 370 } 371 372 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 373 { 374 skb->encapsulation = 1; 375 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 376 return ipv6_gro_complete(skb, nhoff); 377 } 378 379 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 380 { 381 skb->encapsulation = 1; 382 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 383 return ipv6_gro_complete(skb, nhoff); 384 } 385 386 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 387 { 388 skb->encapsulation = 1; 389 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 390 return inet_gro_complete(skb, nhoff); 391 } 392 393 static struct packet_offload ipv6_packet_offload __read_mostly = { 394 .type = cpu_to_be16(ETH_P_IPV6), 395 .callbacks = { 396 .gso_segment = ipv6_gso_segment, 397 .gro_receive = ipv6_gro_receive, 398 .gro_complete = ipv6_gro_complete, 399 }, 400 }; 401 402 static struct sk_buff *sit_gso_segment(struct sk_buff *skb, 403 netdev_features_t features) 404 { 405 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4)) 406 return ERR_PTR(-EINVAL); 407 408 return ipv6_gso_segment(skb, features); 409 } 410 411 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb, 412 netdev_features_t features) 413 { 414 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 415 return ERR_PTR(-EINVAL); 416 417 return inet_gso_segment(skb, features); 418 } 419 420 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb, 421 netdev_features_t features) 422 { 423 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 424 return ERR_PTR(-EINVAL); 425 426 return ipv6_gso_segment(skb, features); 427 } 428 429 static const struct net_offload sit_offload = { 430 .callbacks = { 431 .gso_segment = sit_gso_segment, 432 .gro_receive = sit_ip6ip6_gro_receive, 433 .gro_complete = sit_gro_complete, 434 }, 435 }; 436 437 static const struct net_offload ip4ip6_offload = { 438 .callbacks = { 439 .gso_segment = ip4ip6_gso_segment, 440 .gro_receive = ip4ip6_gro_receive, 441 .gro_complete = ip4ip6_gro_complete, 442 }, 443 }; 444 445 static const struct net_offload ip6ip6_offload = { 446 .callbacks = { 447 .gso_segment = ip6ip6_gso_segment, 448 .gro_receive = sit_ip6ip6_gro_receive, 449 .gro_complete = ip6ip6_gro_complete, 450 }, 451 }; 452 static int __init ipv6_offload_init(void) 453 { 454 455 if (tcpv6_offload_init() < 0) 456 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 457 if (ipv6_exthdrs_offload_init() < 0) 458 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 459 460 dev_add_offload(&ipv6_packet_offload); 461 462 inet_add_offload(&sit_offload, IPPROTO_IPV6); 463 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 464 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 465 466 return 0; 467 } 468 469 fs_initcall(ipv6_offload_init); 470