1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IPV4 GSO/GRO offload support 4 * Linux INET implementation 5 * 6 * UDPv4 GSO support 7 */ 8 9 #include <linux/skbuff.h> 10 #include <net/gro.h> 11 #include <net/gso.h> 12 #include <net/udp.h> 13 #include <net/protocol.h> 14 #include <net/inet_common.h> 15 #include <net/udp_tunnel.h> 16 17 #if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) 18 19 /* 20 * Dummy GRO tunnel callback, exists mainly to avoid dangling/NULL 21 * values for the udp tunnel static call. 22 */ 23 static struct sk_buff *dummy_gro_rcv(struct sock *sk, 24 struct list_head *head, 25 struct sk_buff *skb) 26 { 27 NAPI_GRO_CB(skb)->flush = 1; 28 return NULL; 29 } 30 31 typedef struct sk_buff *(*udp_tunnel_gro_rcv_t)(struct sock *sk, 32 struct list_head *head, 33 struct sk_buff *skb); 34 35 struct udp_tunnel_type_entry { 36 udp_tunnel_gro_rcv_t gro_receive; 37 refcount_t count; 38 }; 39 40 #define UDP_MAX_TUNNEL_TYPES (IS_ENABLED(CONFIG_GENEVE) + \ 41 IS_ENABLED(CONFIG_VXLAN) * 2 + \ 42 IS_ENABLED(CONFIG_NET_FOU) * 2 + \ 43 IS_ENABLED(CONFIG_XFRM) * 2) 44 45 DEFINE_STATIC_CALL(udp_tunnel_gro_rcv, dummy_gro_rcv); 46 static DEFINE_STATIC_KEY_FALSE(udp_tunnel_static_call); 47 static DEFINE_MUTEX(udp_tunnel_gro_type_lock); 48 static struct udp_tunnel_type_entry udp_tunnel_gro_types[UDP_MAX_TUNNEL_TYPES]; 49 static unsigned int udp_tunnel_gro_type_nr; 50 static DEFINE_SPINLOCK(udp_tunnel_gro_lock); 51 52 void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add) 53 { 54 bool is_ipv6 = sk->sk_family == AF_INET6; 55 struct udp_sock *tup, *up = udp_sk(sk); 56 struct udp_tunnel_gro *udp_tunnel_gro; 57 58 spin_lock(&udp_tunnel_gro_lock); 59 udp_tunnel_gro = &net->ipv4.udp_tunnel_gro[is_ipv6]; 60 if (add) 61 hlist_add_head(&up->tunnel_list, &udp_tunnel_gro->list); 62 else if (up->tunnel_list.pprev) 63 hlist_del_init(&up->tunnel_list); 64 65 if (udp_tunnel_gro->list.first && 66 !udp_tunnel_gro->list.first->next) { 67 tup = hlist_entry(udp_tunnel_gro->list.first, struct udp_sock, 68 tunnel_list); 69 70 rcu_assign_pointer(udp_tunnel_gro->sk, (struct sock *)tup); 71 } else { 72 RCU_INIT_POINTER(udp_tunnel_gro->sk, NULL); 73 } 74 75 spin_unlock(&udp_tunnel_gro_lock); 76 } 77 EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_lookup); 78 79 void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) 80 { 81 struct udp_tunnel_type_entry *cur = NULL; 82 struct udp_sock *up = udp_sk(sk); 83 int i, old_gro_type_nr; 84 85 if (!UDP_MAX_TUNNEL_TYPES || !up->gro_receive) 86 return; 87 88 mutex_lock(&udp_tunnel_gro_type_lock); 89 90 /* Check if the static call is permanently disabled. */ 91 if (udp_tunnel_gro_type_nr > UDP_MAX_TUNNEL_TYPES) 92 goto out; 93 94 for (i = 0; i < udp_tunnel_gro_type_nr; i++) 95 if (udp_tunnel_gro_types[i].gro_receive == up->gro_receive) 96 cur = &udp_tunnel_gro_types[i]; 97 98 old_gro_type_nr = udp_tunnel_gro_type_nr; 99 if (add) { 100 /* 101 * Update the matching entry, if found, or add a new one 102 * if needed 103 */ 104 if (cur) { 105 refcount_inc(&cur->count); 106 goto out; 107 } 108 109 if (unlikely(udp_tunnel_gro_type_nr == UDP_MAX_TUNNEL_TYPES)) { 110 pr_err_once("Too many UDP tunnel types, please increase UDP_MAX_TUNNEL_TYPES\n"); 111 /* Ensure static call will never be enabled */ 112 udp_tunnel_gro_type_nr = UDP_MAX_TUNNEL_TYPES + 1; 113 } else { 114 cur = &udp_tunnel_gro_types[udp_tunnel_gro_type_nr++]; 115 refcount_set(&cur->count, 1); 116 cur->gro_receive = up->gro_receive; 117 } 118 } else { 119 /* 120 * The stack cleanups only successfully added tunnel, the 121 * lookup on removal should never fail. 122 */ 123 if (WARN_ON_ONCE(!cur)) 124 goto out; 125 126 if (!refcount_dec_and_test(&cur->count)) 127 goto out; 128 129 /* Avoid gaps, so that the enable tunnel has always id 0 */ 130 *cur = udp_tunnel_gro_types[--udp_tunnel_gro_type_nr]; 131 } 132 133 if (udp_tunnel_gro_type_nr == 1) { 134 static_call_update(udp_tunnel_gro_rcv, 135 udp_tunnel_gro_types[0].gro_receive); 136 static_branch_enable(&udp_tunnel_static_call); 137 } else if (old_gro_type_nr == 1) { 138 static_branch_disable(&udp_tunnel_static_call); 139 static_call_update(udp_tunnel_gro_rcv, dummy_gro_rcv); 140 } 141 142 out: 143 mutex_unlock(&udp_tunnel_gro_type_lock); 144 } 145 EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_rcv); 146 147 static struct sk_buff *udp_tunnel_gro_rcv(struct sock *sk, 148 struct list_head *head, 149 struct sk_buff *skb) 150 { 151 if (static_branch_likely(&udp_tunnel_static_call)) { 152 if (unlikely(gro_recursion_inc_test(skb))) { 153 NAPI_GRO_CB(skb)->flush |= 1; 154 return NULL; 155 } 156 return static_call(udp_tunnel_gro_rcv)(sk, head, skb); 157 } 158 return call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb); 159 } 160 161 #else 162 163 static struct sk_buff *udp_tunnel_gro_rcv(struct sock *sk, 164 struct list_head *head, 165 struct sk_buff *skb) 166 { 167 return call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb); 168 } 169 170 #endif 171 172 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, 173 netdev_features_t features, 174 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 175 netdev_features_t features), 176 __be16 new_protocol, bool is_ipv6) 177 { 178 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); 179 bool remcsum, need_csum, offload_csum, gso_partial; 180 struct sk_buff *segs = ERR_PTR(-EINVAL); 181 struct udphdr *uh = udp_hdr(skb); 182 u16 mac_offset = skb->mac_header; 183 __be16 protocol = skb->protocol; 184 u16 mac_len = skb->mac_len; 185 int udp_offset, outer_hlen; 186 __wsum partial; 187 bool need_ipsec; 188 189 if (unlikely(!pskb_may_pull(skb, tnl_hlen))) 190 goto out; 191 192 /* Adjust partial header checksum to negate old length. 193 * We cannot rely on the value contained in uh->len as it is 194 * possible that the actual value exceeds the boundaries of the 195 * 16 bit length field due to the header being added outside of an 196 * IP or IPv6 frame that was already limited to 64K - 1. 197 */ 198 if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) 199 partial = (__force __wsum)uh->len; 200 else 201 partial = (__force __wsum)htonl(skb->len); 202 partial = csum_sub(csum_unfold(uh->check), partial); 203 204 /* setup inner skb. */ 205 skb->encapsulation = 0; 206 SKB_GSO_CB(skb)->encap_level = 0; 207 __skb_pull(skb, tnl_hlen); 208 skb_reset_mac_header(skb); 209 skb_set_network_header(skb, skb_inner_network_offset(skb)); 210 skb_set_transport_header(skb, skb_inner_transport_offset(skb)); 211 skb->mac_len = skb_inner_network_offset(skb); 212 skb->protocol = new_protocol; 213 214 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM); 215 skb->encap_hdr_csum = need_csum; 216 217 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM); 218 skb->remcsum_offload = remcsum; 219 220 need_ipsec = (skb_dst(skb) && dst_xfrm(skb_dst(skb))) || skb_sec_path(skb); 221 /* Try to offload checksum if possible */ 222 offload_csum = !!(need_csum && 223 !need_ipsec && 224 (skb->dev->features & 225 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) : 226 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM)))); 227 228 features &= skb->dev->hw_enc_features; 229 if (need_csum) 230 features &= ~NETIF_F_SCTP_CRC; 231 232 /* The only checksum offload we care about from here on out is the 233 * outer one so strip the existing checksum feature flags and 234 * instead set the flag based on our outer checksum offload value. 235 */ 236 if (remcsum) { 237 features &= ~NETIF_F_CSUM_MASK; 238 if (!need_csum || offload_csum) 239 features |= NETIF_F_HW_CSUM; 240 } 241 242 /* segment inner packet. */ 243 segs = gso_inner_segment(skb, features); 244 if (IS_ERR_OR_NULL(segs)) { 245 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, 246 mac_len); 247 goto out; 248 } 249 250 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 251 252 outer_hlen = skb_tnl_header_len(skb); 253 udp_offset = outer_hlen - tnl_hlen; 254 skb = segs; 255 do { 256 unsigned int len; 257 258 if (remcsum) 259 skb->ip_summed = CHECKSUM_NONE; 260 261 /* Set up inner headers if we are offloading inner checksum */ 262 if (skb->ip_summed == CHECKSUM_PARTIAL) { 263 skb_reset_inner_headers(skb); 264 skb->encapsulation = 1; 265 } 266 267 skb->mac_len = mac_len; 268 skb->protocol = protocol; 269 270 __skb_push(skb, outer_hlen); 271 skb_reset_mac_header(skb); 272 skb_set_network_header(skb, mac_len); 273 skb_set_transport_header(skb, udp_offset); 274 len = skb->len - udp_offset; 275 uh = udp_hdr(skb); 276 277 /* If we are only performing partial GSO the inner header 278 * will be using a length value equal to only one MSS sized 279 * segment instead of the entire frame. 280 */ 281 if (gso_partial && skb_is_gso(skb)) { 282 uh->len = htons(skb_shinfo(skb)->gso_size + 283 SKB_GSO_CB(skb)->data_offset + 284 skb->head - (unsigned char *)uh); 285 } else { 286 uh->len = htons(len); 287 } 288 289 if (!need_csum) 290 continue; 291 292 uh->check = ~csum_fold(csum_add(partial, 293 (__force __wsum)htonl(len))); 294 295 if (skb->encapsulation || !offload_csum) { 296 uh->check = gso_make_checksum(skb, ~uh->check); 297 if (uh->check == 0) 298 uh->check = CSUM_MANGLED_0; 299 } else { 300 skb->ip_summed = CHECKSUM_PARTIAL; 301 skb->csum_start = skb_transport_header(skb) - skb->head; 302 skb->csum_offset = offsetof(struct udphdr, check); 303 } 304 } while ((skb = skb->next)); 305 out: 306 return segs; 307 } 308 309 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 310 netdev_features_t features, 311 bool is_ipv6) 312 { 313 const struct net_offload __rcu **offloads; 314 __be16 protocol = skb->protocol; 315 const struct net_offload *ops; 316 struct sk_buff *segs = ERR_PTR(-EINVAL); 317 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 318 netdev_features_t features); 319 320 rcu_read_lock(); 321 322 switch (skb->inner_protocol_type) { 323 case ENCAP_TYPE_ETHER: 324 protocol = skb->inner_protocol; 325 gso_inner_segment = skb_mac_gso_segment; 326 break; 327 case ENCAP_TYPE_IPPROTO: 328 offloads = is_ipv6 ? inet6_offloads : inet_offloads; 329 ops = rcu_dereference(offloads[skb->inner_ipproto]); 330 if (!ops || !ops->callbacks.gso_segment) 331 goto out_unlock; 332 gso_inner_segment = ops->callbacks.gso_segment; 333 break; 334 default: 335 goto out_unlock; 336 } 337 338 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment, 339 protocol, is_ipv6); 340 341 out_unlock: 342 rcu_read_unlock(); 343 344 return segs; 345 } 346 347 static void __udpv4_gso_segment_csum(struct sk_buff *seg, 348 __be32 *oldip, __be32 *newip, 349 __be16 *oldport, __be16 *newport) 350 { 351 struct udphdr *uh; 352 struct iphdr *iph; 353 354 if (*oldip == *newip && *oldport == *newport) 355 return; 356 357 uh = udp_hdr(seg); 358 iph = ip_hdr(seg); 359 360 if (uh->check) { 361 inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip, 362 true); 363 inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport, 364 false); 365 if (!uh->check) 366 uh->check = CSUM_MANGLED_0; 367 } 368 *oldport = *newport; 369 370 csum_replace4(&iph->check, *oldip, *newip); 371 *oldip = *newip; 372 } 373 374 static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs) 375 { 376 struct sk_buff *seg; 377 struct udphdr *uh, *uh2; 378 struct iphdr *iph, *iph2; 379 380 seg = segs; 381 uh = udp_hdr(seg); 382 iph = ip_hdr(seg); 383 384 if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) && 385 (udp_hdr(seg)->source == udp_hdr(seg->next)->source) && 386 (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) && 387 (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr)) 388 return segs; 389 390 while ((seg = seg->next)) { 391 uh2 = udp_hdr(seg); 392 iph2 = ip_hdr(seg); 393 394 __udpv4_gso_segment_csum(seg, 395 &iph2->saddr, &iph->saddr, 396 &uh2->source, &uh->source); 397 __udpv4_gso_segment_csum(seg, 398 &iph2->daddr, &iph->daddr, 399 &uh2->dest, &uh->dest); 400 } 401 402 return segs; 403 } 404 405 static void __udpv6_gso_segment_csum(struct sk_buff *seg, 406 struct in6_addr *oldip, 407 const struct in6_addr *newip, 408 __be16 *oldport, __be16 newport) 409 { 410 struct udphdr *uh = udp_hdr(seg); 411 412 if (ipv6_addr_equal(oldip, newip) && *oldport == newport) 413 return; 414 415 if (uh->check) { 416 inet_proto_csum_replace16(&uh->check, seg, oldip->s6_addr32, 417 newip->s6_addr32, true); 418 419 inet_proto_csum_replace2(&uh->check, seg, *oldport, newport, 420 false); 421 if (!uh->check) 422 uh->check = CSUM_MANGLED_0; 423 } 424 425 *oldip = *newip; 426 *oldport = newport; 427 } 428 429 static struct sk_buff *__udpv6_gso_segment_list_csum(struct sk_buff *segs) 430 { 431 const struct ipv6hdr *iph; 432 const struct udphdr *uh; 433 struct ipv6hdr *iph2; 434 struct sk_buff *seg; 435 struct udphdr *uh2; 436 437 seg = segs; 438 uh = udp_hdr(seg); 439 iph = ipv6_hdr(seg); 440 uh2 = udp_hdr(seg->next); 441 iph2 = ipv6_hdr(seg->next); 442 443 if (!(*(const u32 *)&uh->source ^ *(const u32 *)&uh2->source) && 444 ipv6_addr_equal(&iph->saddr, &iph2->saddr) && 445 ipv6_addr_equal(&iph->daddr, &iph2->daddr)) 446 return segs; 447 448 while ((seg = seg->next)) { 449 uh2 = udp_hdr(seg); 450 iph2 = ipv6_hdr(seg); 451 452 __udpv6_gso_segment_csum(seg, &iph2->saddr, &iph->saddr, 453 &uh2->source, uh->source); 454 __udpv6_gso_segment_csum(seg, &iph2->daddr, &iph->daddr, 455 &uh2->dest, uh->dest); 456 } 457 458 return segs; 459 } 460 461 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb, 462 netdev_features_t features, 463 bool is_ipv6) 464 { 465 unsigned int mss = skb_shinfo(skb)->gso_size; 466 467 skb = skb_segment_list(skb, features, skb_mac_header_len(skb)); 468 if (IS_ERR(skb)) 469 return skb; 470 471 udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss); 472 473 if (is_ipv6) 474 return __udpv6_gso_segment_list_csum(skb); 475 else 476 return __udpv4_gso_segment_list_csum(skb); 477 } 478 479 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 480 netdev_features_t features, bool is_ipv6) 481 { 482 struct sock *sk = gso_skb->sk; 483 unsigned int sum_truesize = 0; 484 struct sk_buff *segs, *seg; 485 __be16 newlen, msslen; 486 struct udphdr *uh; 487 unsigned int mss; 488 bool copy_dtor; 489 __sum16 check; 490 int ret = 0; 491 492 mss = skb_shinfo(gso_skb)->gso_size; 493 if (gso_skb->len <= sizeof(*uh) + mss) 494 return ERR_PTR(-EINVAL); 495 496 if (unlikely(skb_checksum_start(gso_skb) != 497 skb_transport_header(gso_skb) && 498 !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST))) 499 return ERR_PTR(-EINVAL); 500 501 /* We don't know if egress device can segment and checksum the packet 502 * when IPv6 extension headers are present. Fall back to software GSO. 503 */ 504 if (gso_skb->ip_summed != CHECKSUM_PARTIAL) 505 features &= ~(NETIF_F_GSO_UDP_L4 | NETIF_F_CSUM_MASK); 506 507 if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) { 508 /* Packet is from an untrusted source, reset gso_segs. */ 509 skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh), 510 mss); 511 return NULL; 512 } 513 514 if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) { 515 /* Detect modified geometry and pass those to skb_segment. */ 516 if ((skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size) && 517 !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_DODGY)) 518 return __udp_gso_segment_list(gso_skb, features, is_ipv6); 519 520 ret = __skb_linearize(gso_skb); 521 if (ret) 522 return ERR_PTR(ret); 523 524 /* Setup csum, as fraglist skips this in udp4_gro_receive. */ 525 gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head; 526 gso_skb->csum_offset = offsetof(struct udphdr, check); 527 gso_skb->ip_summed = CHECKSUM_PARTIAL; 528 529 uh = udp_hdr(gso_skb); 530 if (is_ipv6) 531 uh->check = ~udp_v6_check(gso_skb->len, 532 &ipv6_hdr(gso_skb)->saddr, 533 &ipv6_hdr(gso_skb)->daddr, 0); 534 else 535 uh->check = ~udp_v4_check(gso_skb->len, 536 ip_hdr(gso_skb)->saddr, 537 ip_hdr(gso_skb)->daddr, 0); 538 } 539 540 skb_pull(gso_skb, sizeof(*uh)); 541 542 /* clear destructor to avoid skb_segment assigning it to tail */ 543 copy_dtor = gso_skb->destructor == sock_wfree; 544 if (copy_dtor) { 545 gso_skb->destructor = NULL; 546 gso_skb->sk = NULL; 547 } 548 549 segs = skb_segment(gso_skb, features); 550 if (IS_ERR_OR_NULL(segs)) { 551 if (copy_dtor) { 552 gso_skb->destructor = sock_wfree; 553 gso_skb->sk = sk; 554 } 555 return segs; 556 } 557 558 msslen = htons(sizeof(*uh) + mss); 559 560 /* GSO partial and frag_list segmentation only requires splitting 561 * the frame into an MSS multiple and possibly a remainder, both 562 * cases return a GSO skb. So update the mss now. 563 */ 564 if (skb_is_gso(segs)) 565 mss *= skb_shinfo(segs)->gso_segs; 566 567 seg = segs; 568 uh = udp_hdr(seg); 569 570 /* preserve TX timestamp flags and TS key for first segment */ 571 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey; 572 skb_shinfo(seg)->tx_flags |= 573 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP); 574 575 /* compute checksum adjustment based on old length versus new */ 576 newlen = htons(sizeof(*uh) + mss); 577 check = csum16_add(csum16_sub(uh->check, uh->len), newlen); 578 579 for (;;) { 580 if (copy_dtor) { 581 seg->destructor = sock_wfree; 582 seg->sk = sk; 583 sum_truesize += seg->truesize; 584 } 585 586 if (!seg->next) 587 break; 588 589 uh->len = msslen; 590 uh->check = check; 591 592 if (seg->ip_summed == CHECKSUM_PARTIAL) 593 gso_reset_checksum(seg, ~check); 594 else 595 uh->check = gso_make_checksum(seg, ~check) ? : 596 CSUM_MANGLED_0; 597 598 seg = seg->next; 599 uh = udp_hdr(seg); 600 } 601 602 /* last packet can be partial gso_size, account for that in checksum */ 603 newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) + 604 seg->data_len); 605 check = csum16_add(csum16_sub(uh->check, uh->len), newlen); 606 607 uh->len = newlen; 608 uh->check = check; 609 610 if (seg->ip_summed == CHECKSUM_PARTIAL) 611 gso_reset_checksum(seg, ~check); 612 else 613 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0; 614 615 /* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same 616 * meaning. However, check for bad offloads in the GSO stack expects the 617 * latter, if the checksum was calculated in software. To vouch for the 618 * segment skbs we actually need to set it on the gso_skb. 619 */ 620 if (gso_skb->ip_summed == CHECKSUM_NONE) 621 gso_skb->ip_summed = CHECKSUM_UNNECESSARY; 622 623 /* update refcount for the packet */ 624 if (copy_dtor) { 625 int delta = sum_truesize - gso_skb->truesize; 626 627 /* In some pathological cases, delta can be negative. 628 * We need to either use refcount_add() or refcount_sub_and_test() 629 */ 630 if (likely(delta >= 0)) 631 refcount_add(delta, &sk->sk_wmem_alloc); 632 else 633 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); 634 } 635 return segs; 636 } 637 638 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, 639 netdev_features_t features) 640 { 641 struct sk_buff *segs = ERR_PTR(-EINVAL); 642 unsigned int mss; 643 __wsum csum; 644 struct udphdr *uh; 645 struct iphdr *iph; 646 647 if (skb->encapsulation && 648 (skb_shinfo(skb)->gso_type & 649 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { 650 segs = skb_udp_tunnel_segment(skb, features, false); 651 goto out; 652 } 653 654 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4))) 655 goto out; 656 657 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 658 goto out; 659 660 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) 661 return __udp_gso_segment(skb, features, false); 662 663 mss = skb_shinfo(skb)->gso_size; 664 if (unlikely(skb->len <= mss)) 665 goto out; 666 667 /* Do software UFO. Complete and fill in the UDP checksum as 668 * HW cannot do checksum of UDP packets sent as multiple 669 * IP fragments. 670 */ 671 672 uh = udp_hdr(skb); 673 iph = ip_hdr(skb); 674 675 uh->check = 0; 676 csum = skb_checksum(skb, 0, skb->len, 0); 677 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum); 678 if (uh->check == 0) 679 uh->check = CSUM_MANGLED_0; 680 681 skb->ip_summed = CHECKSUM_UNNECESSARY; 682 683 /* If there is no outer header we can fake a checksum offload 684 * due to the fact that we have already done the checksum in 685 * software prior to segmenting the frame. 686 */ 687 if (!skb->encap_hdr_csum) 688 features |= NETIF_F_HW_CSUM; 689 690 /* Fragment the skb. IP headers of the fragments are updated in 691 * inet_gso_segment() 692 */ 693 segs = skb_segment(skb, features); 694 out: 695 return segs; 696 } 697 698 699 #define UDP_GRO_CNT_MAX 64 700 static struct sk_buff *udp_gro_receive_segment(struct list_head *head, 701 struct sk_buff *skb) 702 { 703 struct udphdr *uh = udp_gro_udphdr(skb); 704 struct sk_buff *pp = NULL; 705 struct udphdr *uh2; 706 struct sk_buff *p; 707 unsigned int ulen; 708 int ret = 0; 709 int flush; 710 711 /* requires non zero csum, for symmetry with GSO */ 712 if (!uh->check) { 713 NAPI_GRO_CB(skb)->flush = 1; 714 return NULL; 715 } 716 717 /* Do not deal with padded or malicious packets, sorry ! */ 718 ulen = ntohs(uh->len); 719 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) { 720 NAPI_GRO_CB(skb)->flush = 1; 721 return NULL; 722 } 723 /* pull encapsulating udp header */ 724 skb_gro_pull(skb, sizeof(struct udphdr)); 725 726 list_for_each_entry(p, head, list) { 727 if (!NAPI_GRO_CB(p)->same_flow) 728 continue; 729 730 uh2 = udp_hdr(p); 731 732 /* Match ports only, as csum is always non zero */ 733 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { 734 NAPI_GRO_CB(p)->same_flow = 0; 735 continue; 736 } 737 738 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) { 739 NAPI_GRO_CB(skb)->flush = 1; 740 return p; 741 } 742 743 flush = gro_receive_network_flush(uh, uh2, p); 744 745 /* Terminate the flow on len mismatch or if it grow "too much". 746 * Under small packet flood GRO count could elsewhere grow a lot 747 * leading to excessive truesize values. 748 * On len mismatch merge the first packet shorter than gso_size, 749 * otherwise complete the GRO packet. 750 */ 751 if (ulen > ntohs(uh2->len) || flush) { 752 pp = p; 753 } else { 754 if (NAPI_GRO_CB(skb)->is_flist) { 755 if (!pskb_may_pull(skb, skb_gro_offset(skb))) { 756 NAPI_GRO_CB(skb)->flush = 1; 757 return NULL; 758 } 759 if ((skb->ip_summed != p->ip_summed) || 760 (skb->csum_level != p->csum_level)) { 761 NAPI_GRO_CB(skb)->flush = 1; 762 return NULL; 763 } 764 skb_set_network_header(skb, skb_gro_receive_network_offset(skb)); 765 ret = skb_gro_receive_list(p, skb); 766 } else { 767 skb_gro_postpull_rcsum(skb, uh, 768 sizeof(struct udphdr)); 769 770 ret = skb_gro_receive(p, skb); 771 } 772 } 773 774 if (ret || ulen != ntohs(uh2->len) || 775 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX) 776 pp = p; 777 778 return pp; 779 } 780 781 /* mismatch, but we never need to flush */ 782 return NULL; 783 } 784 785 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, 786 struct udphdr *uh, struct sock *sk) 787 { 788 struct sk_buff *pp = NULL; 789 struct sk_buff *p; 790 struct udphdr *uh2; 791 unsigned int off = skb_gro_offset(skb); 792 int flush = 1; 793 794 /* We can do L4 aggregation only if the packet can't land in a tunnel 795 * otherwise we could corrupt the inner stream. Detecting such packets 796 * cannot be foolproof and the aggregation might still happen in some 797 * cases. Such packets should be caught in udp_unexpected_gso later. 798 */ 799 NAPI_GRO_CB(skb)->is_flist = 0; 800 if (!sk || !udp_sk(sk)->gro_receive) { 801 /* If the packet was locally encapsulated in a UDP tunnel that 802 * wasn't detected above, do not GRO. 803 */ 804 if (skb->encapsulation) 805 goto out; 806 807 if (skb->dev->features & NETIF_F_GRO_FRAGLIST) 808 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1; 809 810 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) || 811 (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist) 812 return call_gro_receive(udp_gro_receive_segment, head, skb); 813 814 /* no GRO, be sure flush the current packet */ 815 goto out; 816 } 817 818 if (NAPI_GRO_CB(skb)->encap_mark || 819 (uh->check && skb->ip_summed != CHECKSUM_PARTIAL && 820 NAPI_GRO_CB(skb)->csum_cnt == 0 && 821 !NAPI_GRO_CB(skb)->csum_valid)) 822 goto out; 823 824 /* mark that this skb passed once through the tunnel gro layer */ 825 NAPI_GRO_CB(skb)->encap_mark = 1; 826 827 flush = 0; 828 829 list_for_each_entry(p, head, list) { 830 if (!NAPI_GRO_CB(p)->same_flow) 831 continue; 832 833 uh2 = (struct udphdr *)(p->data + off); 834 835 /* Match ports and either checksums are either both zero 836 * or nonzero. 837 */ 838 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || 839 (!uh->check ^ !uh2->check)) { 840 NAPI_GRO_CB(p)->same_flow = 0; 841 continue; 842 } 843 } 844 845 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ 846 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); 847 pp = udp_tunnel_gro_rcv(sk, head, skb); 848 849 out: 850 skb_gro_flush_final(skb, pp, flush); 851 return pp; 852 } 853 854 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport, 855 __be16 dport) 856 { 857 const struct iphdr *iph = skb_gro_network_header(skb); 858 struct net *net = dev_net_rcu(skb->dev); 859 struct sock *sk; 860 int iif, sdif; 861 862 sk = udp_tunnel_sk(net, false); 863 if (sk && dport == htons(sk->sk_num)) 864 return sk; 865 866 inet_get_iif_sdif(skb, &iif, &sdif); 867 868 return __udp4_lib_lookup(net, iph->saddr, sport, 869 iph->daddr, dport, iif, sdif, NULL); 870 } 871 872 INDIRECT_CALLABLE_SCOPE 873 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb) 874 { 875 struct udphdr *uh = udp_gro_udphdr(skb); 876 struct sock *sk = NULL; 877 struct sk_buff *pp; 878 879 if (unlikely(!uh)) 880 goto flush; 881 882 /* Don't bother verifying checksum if we're going to flush anyway. */ 883 if (NAPI_GRO_CB(skb)->flush) 884 goto skip; 885 886 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 887 inet_gro_compute_pseudo)) 888 goto flush; 889 else if (uh->check) 890 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, 891 inet_gro_compute_pseudo); 892 skip: 893 if (static_branch_unlikely(&udp_encap_needed_key)) 894 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest); 895 896 pp = udp_gro_receive(head, skb, uh, sk); 897 return pp; 898 899 flush: 900 NAPI_GRO_CB(skb)->flush = 1; 901 return NULL; 902 } 903 904 static int udp_gro_complete_segment(struct sk_buff *skb) 905 { 906 struct udphdr *uh = udp_hdr(skb); 907 908 skb->csum_start = (unsigned char *)uh - skb->head; 909 skb->csum_offset = offsetof(struct udphdr, check); 910 skb->ip_summed = CHECKSUM_PARTIAL; 911 912 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 913 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4; 914 915 if (skb->encapsulation) 916 skb->inner_transport_header = skb->transport_header; 917 918 return 0; 919 } 920 921 int udp_gro_complete(struct sk_buff *skb, int nhoff, 922 udp_lookup_t lookup) 923 { 924 __be16 newlen = htons(skb->len - nhoff); 925 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 926 struct sock *sk; 927 int err; 928 929 uh->len = newlen; 930 931 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb, 932 udp4_lib_lookup_skb, skb, uh->source, uh->dest); 933 if (sk && udp_sk(sk)->gro_complete) { 934 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM 935 : SKB_GSO_UDP_TUNNEL; 936 937 /* clear the encap mark, so that inner frag_list gro_complete 938 * can take place 939 */ 940 NAPI_GRO_CB(skb)->encap_mark = 0; 941 942 /* Set encapsulation before calling into inner gro_complete() 943 * functions to make them set up the inner offsets. 944 */ 945 skb->encapsulation = 1; 946 err = udp_sk(sk)->gro_complete(sk, skb, 947 nhoff + sizeof(struct udphdr)); 948 } else { 949 err = udp_gro_complete_segment(skb); 950 } 951 952 if (skb->remcsum_offload) 953 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; 954 955 return err; 956 } 957 958 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff) 959 { 960 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation]; 961 const struct iphdr *iph = (struct iphdr *)(skb->data + offset); 962 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 963 964 /* do fraglist only if there is no outer UDP encap (or we already processed it) */ 965 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) { 966 uh->len = htons(skb->len - nhoff); 967 968 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); 969 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 970 971 __skb_incr_checksum_unnecessary(skb); 972 973 return 0; 974 } 975 976 if (uh->check) 977 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, 978 iph->daddr, 0); 979 980 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb); 981 } 982 983 int __init udpv4_offload_init(void) 984 { 985 net_hotdata.udpv4_offload = (struct net_offload) { 986 .callbacks = { 987 .gso_segment = udp4_ufo_fragment, 988 .gro_receive = udp4_gro_receive, 989 .gro_complete = udp4_gro_complete, 990 }, 991 }; 992 993 return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP); 994 } 995