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 struct udphdr *uh; 486 unsigned int mss; 487 bool copy_dtor; 488 __sum16 check; 489 __be16 newlen; 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 seg = segs; 559 uh = udp_hdr(seg); 560 561 /* preserve TX timestamp flags and TS key for first segment */ 562 skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey; 563 skb_shinfo(seg)->tx_flags |= 564 (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP); 565 566 /* compute checksum adjustment based on old length versus new */ 567 newlen = htons(sizeof(*uh) + mss); 568 check = csum16_add(csum16_sub(uh->check, uh->len), newlen); 569 570 for (;;) { 571 if (copy_dtor) { 572 seg->destructor = sock_wfree; 573 seg->sk = sk; 574 sum_truesize += seg->truesize; 575 } 576 577 if (!seg->next) 578 break; 579 580 uh->len = newlen; 581 uh->check = check; 582 583 if (seg->ip_summed == CHECKSUM_PARTIAL) 584 gso_reset_checksum(seg, ~check); 585 else 586 uh->check = gso_make_checksum(seg, ~check) ? : 587 CSUM_MANGLED_0; 588 589 seg = seg->next; 590 uh = udp_hdr(seg); 591 } 592 593 /* Unless skb fits perfectly as GSO_PARTIAL, the trailing 594 * segment may not be full MSS, account for that in the checksum 595 */ 596 if (!skb_is_gso(seg)) 597 newlen = htons(skb_tail_pointer(seg) - 598 skb_transport_header(seg) + seg->data_len); 599 check = csum16_add(csum16_sub(uh->check, uh->len), newlen); 600 601 uh->len = newlen; 602 uh->check = check; 603 604 if (seg->ip_summed == CHECKSUM_PARTIAL) 605 gso_reset_checksum(seg, ~check); 606 else 607 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0; 608 609 /* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same 610 * meaning. However, check for bad offloads in the GSO stack expects the 611 * latter, if the checksum was calculated in software. To vouch for the 612 * segment skbs we actually need to set it on the gso_skb. 613 */ 614 if (gso_skb->ip_summed == CHECKSUM_NONE) 615 gso_skb->ip_summed = CHECKSUM_UNNECESSARY; 616 617 /* update refcount for the packet */ 618 if (copy_dtor) { 619 int delta = sum_truesize - gso_skb->truesize; 620 621 /* In some pathological cases, delta can be negative. 622 * We need to either use refcount_add() or refcount_sub_and_test() 623 */ 624 if (likely(delta >= 0)) 625 refcount_add(delta, &sk->sk_wmem_alloc); 626 else 627 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); 628 } 629 return segs; 630 } 631 632 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, 633 netdev_features_t features) 634 { 635 struct sk_buff *segs = ERR_PTR(-EINVAL); 636 unsigned int mss; 637 __wsum csum; 638 struct udphdr *uh; 639 struct iphdr *iph; 640 641 if (skb->encapsulation && 642 (skb_shinfo(skb)->gso_type & 643 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { 644 segs = skb_udp_tunnel_segment(skb, features, false); 645 goto out; 646 } 647 648 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4))) 649 goto out; 650 651 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 652 goto out; 653 654 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) 655 return __udp_gso_segment(skb, features, false); 656 657 mss = skb_shinfo(skb)->gso_size; 658 if (unlikely(skb->len <= mss)) 659 goto out; 660 661 /* Do software UFO. Complete and fill in the UDP checksum as 662 * HW cannot do checksum of UDP packets sent as multiple 663 * IP fragments. 664 */ 665 666 uh = udp_hdr(skb); 667 iph = ip_hdr(skb); 668 669 uh->check = 0; 670 csum = skb_checksum(skb, 0, skb->len, 0); 671 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum); 672 if (uh->check == 0) 673 uh->check = CSUM_MANGLED_0; 674 675 skb->ip_summed = CHECKSUM_UNNECESSARY; 676 677 /* If there is no outer header we can fake a checksum offload 678 * due to the fact that we have already done the checksum in 679 * software prior to segmenting the frame. 680 */ 681 if (!skb->encap_hdr_csum) 682 features |= NETIF_F_HW_CSUM; 683 684 /* Fragment the skb. IP headers of the fragments are updated in 685 * inet_gso_segment() 686 */ 687 segs = skb_segment(skb, features); 688 out: 689 return segs; 690 } 691 692 693 #define UDP_GRO_CNT_MAX 64 694 static struct sk_buff *udp_gro_receive_segment(struct list_head *head, 695 struct sk_buff *skb) 696 { 697 struct udphdr *uh = udp_gro_udphdr(skb); 698 struct sk_buff *pp = NULL; 699 struct udphdr *uh2; 700 struct sk_buff *p; 701 unsigned int ulen; 702 int ret = 0; 703 int flush; 704 705 /* requires non zero csum, for symmetry with GSO */ 706 if (!uh->check) { 707 NAPI_GRO_CB(skb)->flush = 1; 708 return NULL; 709 } 710 711 /* Do not deal with padded or malicious packets, sorry ! */ 712 ulen = ntohs(uh->len); 713 if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) { 714 NAPI_GRO_CB(skb)->flush = 1; 715 return NULL; 716 } 717 /* pull encapsulating udp header */ 718 skb_gro_pull(skb, sizeof(struct udphdr)); 719 720 list_for_each_entry(p, head, list) { 721 if (!NAPI_GRO_CB(p)->same_flow) 722 continue; 723 724 uh2 = udp_hdr(p); 725 726 /* Match ports only, as csum is always non zero */ 727 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { 728 NAPI_GRO_CB(p)->same_flow = 0; 729 continue; 730 } 731 732 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) { 733 NAPI_GRO_CB(skb)->flush = 1; 734 return p; 735 } 736 737 flush = gro_receive_network_flush(uh, uh2, p); 738 739 /* Terminate the flow on len mismatch or if it grow "too much". 740 * Under small packet flood GRO count could elsewhere grow a lot 741 * leading to excessive truesize values. 742 * On len mismatch merge the first packet shorter than gso_size, 743 * otherwise complete the GRO packet. 744 */ 745 if (ulen > ntohs(uh2->len) || flush) { 746 pp = p; 747 } else { 748 if (NAPI_GRO_CB(skb)->is_flist) { 749 if (!pskb_may_pull(skb, skb_gro_offset(skb))) { 750 NAPI_GRO_CB(skb)->flush = 1; 751 return NULL; 752 } 753 if ((skb->ip_summed != p->ip_summed) || 754 (skb->csum_level != p->csum_level)) { 755 NAPI_GRO_CB(skb)->flush = 1; 756 return NULL; 757 } 758 skb_set_network_header(skb, skb_gro_receive_network_offset(skb)); 759 ret = skb_gro_receive_list(p, skb); 760 } else { 761 skb_gro_postpull_rcsum(skb, uh, 762 sizeof(struct udphdr)); 763 764 ret = skb_gro_receive(p, skb); 765 } 766 } 767 768 if (ret || ulen != ntohs(uh2->len) || 769 NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX) 770 pp = p; 771 772 return pp; 773 } 774 775 /* mismatch, but we never need to flush */ 776 return NULL; 777 } 778 779 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, 780 struct udphdr *uh, struct sock *sk) 781 { 782 struct sk_buff *pp = NULL; 783 struct sk_buff *p; 784 struct udphdr *uh2; 785 unsigned int off = skb_gro_offset(skb); 786 int flush = 1; 787 788 /* We can do L4 aggregation only if the packet can't land in a tunnel 789 * otherwise we could corrupt the inner stream. Detecting such packets 790 * cannot be foolproof and the aggregation might still happen in some 791 * cases. Such packets should be caught in udp_unexpected_gso later. 792 */ 793 NAPI_GRO_CB(skb)->is_flist = 0; 794 if (!sk || !udp_sk(sk)->gro_receive) { 795 /* If the packet was locally encapsulated in a UDP tunnel that 796 * wasn't detected above, do not GRO. 797 */ 798 if (skb->encapsulation) 799 goto out; 800 801 if (skb->dev->features & NETIF_F_GRO_FRAGLIST) 802 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1; 803 804 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) || 805 (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist) 806 return call_gro_receive(udp_gro_receive_segment, head, skb); 807 808 /* no GRO, be sure flush the current packet */ 809 goto out; 810 } 811 812 if (NAPI_GRO_CB(skb)->encap_mark || 813 (uh->check && skb->ip_summed != CHECKSUM_PARTIAL && 814 NAPI_GRO_CB(skb)->csum_cnt == 0 && 815 !NAPI_GRO_CB(skb)->csum_valid)) 816 goto out; 817 818 /* mark that this skb passed once through the tunnel gro layer */ 819 NAPI_GRO_CB(skb)->encap_mark = 1; 820 821 flush = 0; 822 823 list_for_each_entry(p, head, list) { 824 if (!NAPI_GRO_CB(p)->same_flow) 825 continue; 826 827 uh2 = (struct udphdr *)(p->data + off); 828 829 /* Match ports and either checksums are either both zero 830 * or nonzero. 831 */ 832 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || 833 (!uh->check ^ !uh2->check)) { 834 NAPI_GRO_CB(p)->same_flow = 0; 835 continue; 836 } 837 } 838 839 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ 840 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); 841 pp = udp_tunnel_gro_rcv(sk, head, skb); 842 843 out: 844 skb_gro_flush_final(skb, pp, flush); 845 return pp; 846 } 847 848 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport, 849 __be16 dport) 850 { 851 const struct iphdr *iph = skb_gro_network_header(skb); 852 struct net *net = dev_net_rcu(skb->dev); 853 struct sock *sk; 854 int iif, sdif; 855 856 sk = udp_tunnel_sk(net, false); 857 if (sk && dport == htons(sk->sk_num)) 858 return sk; 859 860 inet_get_iif_sdif(skb, &iif, &sdif); 861 862 return __udp4_lib_lookup(net, iph->saddr, sport, 863 iph->daddr, dport, iif, sdif, NULL); 864 } 865 866 INDIRECT_CALLABLE_SCOPE 867 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb) 868 { 869 struct udphdr *uh = udp_gro_udphdr(skb); 870 struct sock *sk = NULL; 871 struct sk_buff *pp; 872 873 if (unlikely(!uh)) 874 goto flush; 875 876 /* Don't bother verifying checksum if we're going to flush anyway. */ 877 if (NAPI_GRO_CB(skb)->flush) 878 goto skip; 879 880 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 881 inet_gro_compute_pseudo)) 882 goto flush; 883 else if (uh->check) 884 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, 885 inet_gro_compute_pseudo); 886 skip: 887 if (static_branch_unlikely(&udp_encap_needed_key)) 888 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest); 889 890 pp = udp_gro_receive(head, skb, uh, sk); 891 return pp; 892 893 flush: 894 NAPI_GRO_CB(skb)->flush = 1; 895 return NULL; 896 } 897 898 static int udp_gro_complete_segment(struct sk_buff *skb) 899 { 900 struct udphdr *uh = udp_hdr(skb); 901 902 skb->csum_start = (unsigned char *)uh - skb->head; 903 skb->csum_offset = offsetof(struct udphdr, check); 904 skb->ip_summed = CHECKSUM_PARTIAL; 905 906 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 907 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4; 908 909 if (skb->encapsulation) 910 skb->inner_transport_header = skb->transport_header; 911 912 return 0; 913 } 914 915 int udp_gro_complete(struct sk_buff *skb, int nhoff, 916 udp_lookup_t lookup) 917 { 918 __be16 newlen = htons(skb->len - nhoff); 919 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 920 struct sock *sk; 921 int err; 922 923 uh->len = newlen; 924 925 sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb, 926 udp4_lib_lookup_skb, skb, uh->source, uh->dest); 927 if (sk && udp_sk(sk)->gro_complete) { 928 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM 929 : SKB_GSO_UDP_TUNNEL; 930 931 /* clear the encap mark, so that inner frag_list gro_complete 932 * can take place 933 */ 934 NAPI_GRO_CB(skb)->encap_mark = 0; 935 936 /* Set encapsulation before calling into inner gro_complete() 937 * functions to make them set up the inner offsets. 938 */ 939 skb->encapsulation = 1; 940 err = udp_sk(sk)->gro_complete(sk, skb, 941 nhoff + sizeof(struct udphdr)); 942 } else { 943 err = udp_gro_complete_segment(skb); 944 } 945 946 if (skb->remcsum_offload) 947 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; 948 949 return err; 950 } 951 952 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff) 953 { 954 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation]; 955 const struct iphdr *iph = (struct iphdr *)(skb->data + offset); 956 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 957 958 /* do fraglist only if there is no outer UDP encap (or we already processed it) */ 959 if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) { 960 uh->len = htons(skb->len - nhoff); 961 962 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4); 963 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 964 965 __skb_incr_checksum_unnecessary(skb); 966 967 return 0; 968 } 969 970 if (uh->check) 971 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, 972 iph->daddr, 0); 973 974 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb); 975 } 976 977 int __init udpv4_offload_init(void) 978 { 979 net_hotdata.udpv4_offload = (struct net_offload) { 980 .callbacks = { 981 .gso_segment = udp4_ufo_fragment, 982 .gro_receive = udp4_gro_receive, 983 .gro_complete = udp4_gro_complete, 984 }, 985 }; 986 987 return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP); 988 } 989