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 19 #include "ip6_offload.h" 20 21 /* All GRO functions are always builtin, except UDP over ipv6, which lays in 22 * ipv6 module, as it depends on UDPv6 lookup function, so we need special care 23 * when ipv6 is built as a module 24 */ 25 #if IS_BUILTIN(CONFIG_IPV6) 26 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__) 27 #else 28 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__) 29 #endif 30 31 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \ 32 ({ \ 33 unlikely(gro_recursion_inc_test(skb)) ? \ 34 NAPI_GRO_CB(skb)->flush |= 1, NULL : \ 35 INDIRECT_CALL_L4(cb, f2, f1, head, skb); \ 36 }) 37 38 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 39 { 40 const struct net_offload *ops = NULL; 41 42 for (;;) { 43 struct ipv6_opt_hdr *opth; 44 int len; 45 46 if (proto != NEXTHDR_HOP) { 47 ops = rcu_dereference(inet6_offloads[proto]); 48 49 if (unlikely(!ops)) 50 break; 51 52 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 53 break; 54 } 55 56 if (unlikely(!pskb_may_pull(skb, 8))) 57 break; 58 59 opth = (void *)skb->data; 60 len = ipv6_optlen(opth); 61 62 if (unlikely(!pskb_may_pull(skb, len))) 63 break; 64 65 opth = (void *)skb->data; 66 proto = opth->nexthdr; 67 __skb_pull(skb, len); 68 } 69 70 return proto; 71 } 72 73 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 74 netdev_features_t features) 75 { 76 struct sk_buff *segs = ERR_PTR(-EINVAL); 77 struct ipv6hdr *ipv6h; 78 const struct net_offload *ops; 79 int proto; 80 struct frag_hdr *fptr; 81 unsigned int payload_len; 82 u8 *prevhdr; 83 int offset = 0; 84 bool encap, udpfrag; 85 int nhoff; 86 bool gso_partial; 87 88 skb_reset_network_header(skb); 89 nhoff = skb_network_header(skb) - skb_mac_header(skb); 90 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 91 goto out; 92 93 encap = SKB_GSO_CB(skb)->encap_level > 0; 94 if (encap) 95 features &= skb->dev->hw_enc_features; 96 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 97 98 ipv6h = ipv6_hdr(skb); 99 __skb_pull(skb, sizeof(*ipv6h)); 100 segs = ERR_PTR(-EPROTONOSUPPORT); 101 102 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 103 104 if (skb->encapsulation && 105 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 106 udpfrag = proto == IPPROTO_UDP && encap && 107 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 108 else 109 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation && 110 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 111 112 ops = rcu_dereference(inet6_offloads[proto]); 113 if (likely(ops && ops->callbacks.gso_segment)) { 114 skb_reset_transport_header(skb); 115 segs = ops->callbacks.gso_segment(skb, features); 116 } 117 118 if (IS_ERR_OR_NULL(segs)) 119 goto out; 120 121 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 122 123 for (skb = segs; skb; skb = skb->next) { 124 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 125 if (gso_partial && skb_is_gso(skb)) 126 payload_len = skb_shinfo(skb)->gso_size + 127 SKB_GSO_CB(skb)->data_offset + 128 skb->head - (unsigned char *)(ipv6h + 1); 129 else 130 payload_len = skb->len - nhoff - sizeof(*ipv6h); 131 ipv6h->payload_len = htons(payload_len); 132 skb->network_header = (u8 *)ipv6h - skb->head; 133 skb_reset_mac_len(skb); 134 135 if (udpfrag) { 136 int err = ip6_find_1stfragopt(skb, &prevhdr); 137 if (err < 0) { 138 kfree_skb_list(segs); 139 return ERR_PTR(err); 140 } 141 fptr = (struct frag_hdr *)((u8 *)ipv6h + err); 142 fptr->frag_off = htons(offset); 143 if (skb->next) 144 fptr->frag_off |= htons(IP6_MF); 145 offset += (ntohs(ipv6h->payload_len) - 146 sizeof(struct frag_hdr)); 147 } 148 if (encap) 149 skb_reset_inner_headers(skb); 150 } 151 152 out: 153 return segs; 154 } 155 156 /* Return the total length of all the extension hdrs, following the same 157 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 158 */ 159 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 160 const struct net_offload **opps) 161 { 162 struct ipv6_opt_hdr *opth = (void *)iph; 163 int len = 0, proto, optlen = sizeof(*iph); 164 165 proto = iph->nexthdr; 166 for (;;) { 167 if (proto != NEXTHDR_HOP) { 168 *opps = rcu_dereference(inet6_offloads[proto]); 169 if (unlikely(!(*opps))) 170 break; 171 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 172 break; 173 } 174 opth = (void *)opth + optlen; 175 optlen = ipv6_optlen(opth); 176 len += optlen; 177 proto = opth->nexthdr; 178 } 179 return len; 180 } 181 182 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, 183 struct sk_buff *skb) 184 { 185 const struct net_offload *ops; 186 struct sk_buff *pp = NULL; 187 struct sk_buff *p; 188 struct ipv6hdr *iph; 189 unsigned int nlen; 190 unsigned int hlen; 191 unsigned int off; 192 u16 flush = 1; 193 int proto; 194 195 off = skb_gro_offset(skb); 196 hlen = off + sizeof(*iph); 197 iph = skb_gro_header_fast(skb, off); 198 if (skb_gro_header_hard(skb, hlen)) { 199 iph = skb_gro_header_slow(skb, hlen, off); 200 if (unlikely(!iph)) 201 goto out; 202 } 203 204 skb_set_network_header(skb, off); 205 skb_gro_pull(skb, sizeof(*iph)); 206 skb_set_transport_header(skb, skb_gro_offset(skb)); 207 208 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 209 210 rcu_read_lock(); 211 proto = iph->nexthdr; 212 ops = rcu_dereference(inet6_offloads[proto]); 213 if (!ops || !ops->callbacks.gro_receive) { 214 __pskb_pull(skb, skb_gro_offset(skb)); 215 skb_gro_frag0_invalidate(skb); 216 proto = ipv6_gso_pull_exthdrs(skb, proto); 217 skb_gro_pull(skb, -skb_transport_offset(skb)); 218 skb_reset_transport_header(skb); 219 __skb_push(skb, skb_gro_offset(skb)); 220 221 ops = rcu_dereference(inet6_offloads[proto]); 222 if (!ops || !ops->callbacks.gro_receive) 223 goto out_unlock; 224 225 iph = ipv6_hdr(skb); 226 } 227 228 NAPI_GRO_CB(skb)->proto = proto; 229 230 flush--; 231 nlen = skb_network_header_len(skb); 232 233 list_for_each_entry(p, head, list) { 234 const struct ipv6hdr *iph2; 235 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 236 237 if (!NAPI_GRO_CB(p)->same_flow) 238 continue; 239 240 iph2 = (struct ipv6hdr *)(p->data + off); 241 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 242 243 /* All fields must match except length and Traffic Class. 244 * XXX skbs on the gro_list have all been parsed and pulled 245 * already so we don't need to compare nlen 246 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 247 * memcmp() alone below is sufficient, right? 248 */ 249 if ((first_word & htonl(0xF00FFFFF)) || 250 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) || 251 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) || 252 *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) { 253 not_same_flow: 254 NAPI_GRO_CB(p)->same_flow = 0; 255 continue; 256 } 257 if (unlikely(nlen > sizeof(struct ipv6hdr))) { 258 if (memcmp(iph + 1, iph2 + 1, 259 nlen - sizeof(struct ipv6hdr))) 260 goto not_same_flow; 261 } 262 /* flush if Traffic Class fields are different */ 263 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 264 NAPI_GRO_CB(p)->flush |= flush; 265 266 /* If the previous IP ID value was based on an atomic 267 * datagram we can overwrite the value and ignore it. 268 */ 269 if (NAPI_GRO_CB(skb)->is_atomic) 270 NAPI_GRO_CB(p)->flush_id = 0; 271 } 272 273 NAPI_GRO_CB(skb)->is_atomic = true; 274 NAPI_GRO_CB(skb)->flush |= flush; 275 276 skb_gro_postpull_rcsum(skb, iph, nlen); 277 278 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive, 279 ops->callbacks.gro_receive, head, skb); 280 281 out_unlock: 282 rcu_read_unlock(); 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 = (struct ipv6hdr *)(skb->data + nhoff); 324 int err = -ENOSYS; 325 326 if (skb->encapsulation) { 327 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 328 skb_set_inner_network_header(skb, nhoff); 329 } 330 331 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 332 333 rcu_read_lock(); 334 335 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 336 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 337 goto out_unlock; 338 339 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete, 340 udp6_gro_complete, skb, nhoff); 341 342 out_unlock: 343 rcu_read_unlock(); 344 345 return err; 346 } 347 348 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 349 { 350 skb->encapsulation = 1; 351 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 352 return ipv6_gro_complete(skb, nhoff); 353 } 354 355 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 356 { 357 skb->encapsulation = 1; 358 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 359 return ipv6_gro_complete(skb, nhoff); 360 } 361 362 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 363 { 364 skb->encapsulation = 1; 365 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 366 return inet_gro_complete(skb, nhoff); 367 } 368 369 static struct packet_offload ipv6_packet_offload __read_mostly = { 370 .type = cpu_to_be16(ETH_P_IPV6), 371 .callbacks = { 372 .gso_segment = ipv6_gso_segment, 373 .gro_receive = ipv6_gro_receive, 374 .gro_complete = ipv6_gro_complete, 375 }, 376 }; 377 378 static struct sk_buff *sit_gso_segment(struct sk_buff *skb, 379 netdev_features_t features) 380 { 381 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4)) 382 return ERR_PTR(-EINVAL); 383 384 return ipv6_gso_segment(skb, features); 385 } 386 387 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb, 388 netdev_features_t features) 389 { 390 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 391 return ERR_PTR(-EINVAL); 392 393 return inet_gso_segment(skb, features); 394 } 395 396 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb, 397 netdev_features_t features) 398 { 399 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6)) 400 return ERR_PTR(-EINVAL); 401 402 return ipv6_gso_segment(skb, features); 403 } 404 405 static const struct net_offload sit_offload = { 406 .callbacks = { 407 .gso_segment = sit_gso_segment, 408 .gro_receive = sit_ip6ip6_gro_receive, 409 .gro_complete = sit_gro_complete, 410 }, 411 }; 412 413 static const struct net_offload ip4ip6_offload = { 414 .callbacks = { 415 .gso_segment = ip4ip6_gso_segment, 416 .gro_receive = ip4ip6_gro_receive, 417 .gro_complete = ip4ip6_gro_complete, 418 }, 419 }; 420 421 static const struct net_offload ip6ip6_offload = { 422 .callbacks = { 423 .gso_segment = ip6ip6_gso_segment, 424 .gro_receive = sit_ip6ip6_gro_receive, 425 .gro_complete = ip6ip6_gro_complete, 426 }, 427 }; 428 static int __init ipv6_offload_init(void) 429 { 430 431 if (tcpv6_offload_init() < 0) 432 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 433 if (ipv6_exthdrs_offload_init() < 0) 434 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 435 436 dev_add_offload(&ipv6_packet_offload); 437 438 inet_add_offload(&sit_offload, IPPROTO_IPV6); 439 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 440 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 441 442 return 0; 443 } 444 445 fs_initcall(ipv6_offload_init); 446