ipv4/udp_offload.c

   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
  16 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
  17         netdev_features_t features,
  18         struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
  19                                              netdev_features_t features),
  20         __be16 new_protocol, bool is_ipv6)
  21 {
  22         int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
  23         bool remcsum, need_csum, offload_csum, gso_partial;
  24         struct sk_buff *segs = ERR_PTR(-EINVAL);
  25         struct udphdr *uh = udp_hdr(skb);
  26         u16 mac_offset = skb->mac_header;
  27         __be16 protocol = skb->protocol;
  28         u16 mac_len = skb->mac_len;
  29         int udp_offset, outer_hlen;
  30         __wsum partial;
  31         bool need_ipsec;
  32
  33         if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
  34                 goto out;
  35
  36         /* Adjust partial header checksum to negate old length.
  37          * We cannot rely on the value contained in uh->len as it is
  38          * possible that the actual value exceeds the boundaries of the
  39          * 16 bit length field due to the header being added outside of an
  40          * IP or IPv6 frame that was already limited to 64K - 1.
  41          */
  42         if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
  43                 partial = (__force __wsum)uh->len;
  44         else
  45                 partial = (__force __wsum)htonl(skb->len);
  46         partial = csum_sub(csum_unfold(uh->check), partial);
  47
  48         /* setup inner skb. */
  49         skb->encapsulation = 0;
  50         SKB_GSO_CB(skb)->encap_level = 0;
  51         __skb_pull(skb, tnl_hlen);
  52         skb_reset_mac_header(skb);
  53         skb_set_network_header(skb, skb_inner_network_offset(skb));
  54         skb_set_transport_header(skb, skb_inner_transport_offset(skb));
  55         skb->mac_len = skb_inner_network_offset(skb);
  56         skb->protocol = new_protocol;
  57
  58         need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
  59         skb->encap_hdr_csum = need_csum;
  60
  61         remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
  62         skb->remcsum_offload = remcsum;
  63
  64         need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
  65         /* Try to offload checksum if possible */
  66         offload_csum = !!(need_csum &&
  67                           !need_ipsec &&
  68                           (skb->dev->features &
  69                            (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
  70                                       (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
  71
  72         features &= skb->dev->hw_enc_features;
  73         if (need_csum)
  74                 features &= ~NETIF_F_SCTP_CRC;
  75
  76         /* The only checksum offload we care about from here on out is the
  77          * outer one so strip the existing checksum feature flags and
  78          * instead set the flag based on our outer checksum offload value.
  79          */
  80         if (remcsum) {
  81                 features &= ~NETIF_F_CSUM_MASK;
  82                 if (!need_csum || offload_csum)
  83                         features |= NETIF_F_HW_CSUM;
  84         }
  85
  86         /* segment inner packet. */
  87         segs = gso_inner_segment(skb, features);
  88         if (IS_ERR_OR_NULL(segs)) {
  89                 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
  90                                      mac_len);
  91                 goto out;
  92         }
  93
  94         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
  95
  96         outer_hlen = skb_tnl_header_len(skb);
  97         udp_offset = outer_hlen - tnl_hlen;
  98         skb = segs;
  99         do {
 100                 unsigned int len;
 101
 102                 if (remcsum)
 103                         skb->ip_summed = CHECKSUM_NONE;
 104
 105                 /* Set up inner headers if we are offloading inner checksum */
 106                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 107                         skb_reset_inner_headers(skb);
 108                         skb->encapsulation = 1;
 109                 }
 110
 111                 skb->mac_len = mac_len;
 112                 skb->protocol = protocol;
 113
 114                 __skb_push(skb, outer_hlen);
 115                 skb_reset_mac_header(skb);
 116                 skb_set_network_header(skb, mac_len);
 117                 skb_set_transport_header(skb, udp_offset);
 118                 len = skb->len - udp_offset;
 119                 uh = udp_hdr(skb);
 120
 121                 /* If we are only performing partial GSO the inner header
 122                  * will be using a length value equal to only one MSS sized
 123                  * segment instead of the entire frame.
 124                  */
 125                 if (gso_partial && skb_is_gso(skb)) {
 126                         uh->len = htons(skb_shinfo(skb)->gso_size +
 127                                         SKB_GSO_CB(skb)->data_offset +
 128                                         skb->head - (unsigned char *)uh);
 129                 } else {
 130                         uh->len = htons(len);
 131                 }
 132
 133                 if (!need_csum)
 134                         continue;
 135
 136                 uh->check = ~csum_fold(csum_add(partial,
 137                                        (__force __wsum)htonl(len)));
 138
 139                 if (skb->encapsulation || !offload_csum) {
 140                         uh->check = gso_make_checksum(skb, ~uh->check);
 141                         if (uh->check == 0)
 142                                 uh->check = CSUM_MANGLED_0;
 143                 } else {
 144                         skb->ip_summed = CHECKSUM_PARTIAL;
 145                         skb->csum_start = skb_transport_header(skb) - skb->head;
 146                         skb->csum_offset = offsetof(struct udphdr, check);
 147                 }
 148         } while ((skb = skb->next));
 149 out:
 150         return segs;
 151 }
 152
 153 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 154                                        netdev_features_t features,
 155                                        bool is_ipv6)
 156 {
 157         const struct net_offload __rcu **offloads;
 158         __be16 protocol = skb->protocol;
 159         const struct net_offload *ops;
 160         struct sk_buff *segs = ERR_PTR(-EINVAL);
 161         struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
 162                                              netdev_features_t features);
 163
 164         rcu_read_lock();
 165
 166         switch (skb->inner_protocol_type) {
 167         case ENCAP_TYPE_ETHER:
 168                 protocol = skb->inner_protocol;
 169                 gso_inner_segment = skb_mac_gso_segment;
 170                 break;
 171         case ENCAP_TYPE_IPPROTO:
 172                 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
 173                 ops = rcu_dereference(offloads[skb->inner_ipproto]);
 174                 if (!ops || !ops->callbacks.gso_segment)
 175                         goto out_unlock;
 176                 gso_inner_segment = ops->callbacks.gso_segment;
 177                 break;
 178         default:
 179                 goto out_unlock;
 180         }
 181
 182         segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
 183                                         protocol, is_ipv6);
 184
 185 out_unlock:
 186         rcu_read_unlock();
 187
 188         return segs;
 189 }
 190 EXPORT_SYMBOL(skb_udp_tunnel_segment);
 191
 192 static void __udpv4_gso_segment_csum(struct sk_buff *seg,
 193                                      __be32 *oldip, __be32 *newip,
 194                                      __be16 *oldport, __be16 *newport)
 195 {
 196         struct udphdr *uh;
 197         struct iphdr *iph;
 198
 199         if (*oldip == *newip && *oldport == *newport)
 200                 return;
 201
 202         uh = udp_hdr(seg);
 203         iph = ip_hdr(seg);
 204
 205         if (uh->check) {
 206                 inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
 207                                          true);
 208                 inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
 209                                          false);
 210                 if (!uh->check)
 211                         uh->check = CSUM_MANGLED_0;
 212         }
 213         *oldport = *newport;
 214
 215         csum_replace4(&iph->check, *oldip, *newip);
 216         *oldip = *newip;
 217 }
 218
 219 static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
 220 {
 221         struct sk_buff *seg;
 222         struct udphdr *uh, *uh2;
 223         struct iphdr *iph, *iph2;
 224
 225         seg = segs;
 226         uh = udp_hdr(seg);
 227         iph = ip_hdr(seg);
 228
 229         if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
 230             (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
 231             (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
 232             (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
 233                 return segs;
 234
 235         while ((seg = seg->next)) {
 236                 uh2 = udp_hdr(seg);
 237                 iph2 = ip_hdr(seg);
 238
 239                 __udpv4_gso_segment_csum(seg,
 240                                          &iph2->saddr, &iph->saddr,
 241                                          &uh2->source, &uh->source);
 242                 __udpv4_gso_segment_csum(seg,
 243                                          &iph2->daddr, &iph->daddr,
 244                                          &uh2->dest, &uh->dest);
 245         }
 246
 247         return segs;
 248 }
 249
 250 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
 251                                               netdev_features_t features,
 252                                               bool is_ipv6)
 253 {
 254         unsigned int mss = skb_shinfo(skb)->gso_size;
 255
 256         skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
 257         if (IS_ERR(skb))
 258                 return skb;
 259
 260         udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
 261
 262         return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
 263 }
 264
 265 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 266                                   netdev_features_t features, bool is_ipv6)
 267 {
 268         struct sock *sk = gso_skb->sk;
 269         unsigned int sum_truesize = 0;
 270         struct sk_buff *segs, *seg;
 271         struct udphdr *uh;
 272         unsigned int mss;
 273         bool copy_dtor;
 274         __sum16 check;
 275         __be16 newlen;
 276
 277         mss = skb_shinfo(gso_skb)->gso_size;
 278         if (gso_skb->len <= sizeof(*uh) + mss)
 279                 return ERR_PTR(-EINVAL);
 280
 281         if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
 282                 /* Packet is from an untrusted source, reset gso_segs. */
 283                 skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
 284                                                              mss);
 285                 return NULL;
 286         }
 287
 288         if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
 289                 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
 290
 291         skb_pull(gso_skb, sizeof(*uh));
 292
 293         /* clear destructor to avoid skb_segment assigning it to tail */
 294         copy_dtor = gso_skb->destructor == sock_wfree;
 295         if (copy_dtor)
 296                 gso_skb->destructor = NULL;
 297
 298         segs = skb_segment(gso_skb, features);
 299         if (IS_ERR_OR_NULL(segs)) {
 300                 if (copy_dtor)
 301                         gso_skb->destructor = sock_wfree;
 302                 return segs;
 303         }
 304
 305         /* GSO partial and frag_list segmentation only requires splitting
 306          * the frame into an MSS multiple and possibly a remainder, both
 307          * cases return a GSO skb. So update the mss now.
 308          */
 309         if (skb_is_gso(segs))
 310                 mss *= skb_shinfo(segs)->gso_segs;
 311
 312         seg = segs;
 313         uh = udp_hdr(seg);
 314
 315         /* preserve TX timestamp flags and TS key for first segment */
 316         skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
 317         skb_shinfo(seg)->tx_flags |=
 318                         (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
 319
 320         /* compute checksum adjustment based on old length versus new */
 321         newlen = htons(sizeof(*uh) + mss);
 322         check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 323
 324         for (;;) {
 325                 if (copy_dtor) {
 326                         seg->destructor = sock_wfree;
 327                         seg->sk = sk;
 328                         sum_truesize += seg->truesize;
 329                 }
 330
 331                 if (!seg->next)
 332                         break;
 333
 334                 uh->len = newlen;
 335                 uh->check = check;
 336
 337                 if (seg->ip_summed == CHECKSUM_PARTIAL)
 338                         gso_reset_checksum(seg, ~check);
 339                 else
 340                         uh->check = gso_make_checksum(seg, ~check) ? :
 341                                     CSUM_MANGLED_0;
 342
 343                 seg = seg->next;
 344                 uh = udp_hdr(seg);
 345         }
 346
 347         /* last packet can be partial gso_size, account for that in checksum */
 348         newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
 349                        seg->data_len);
 350         check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 351
 352         uh->len = newlen;
 353         uh->check = check;
 354
 355         if (seg->ip_summed == CHECKSUM_PARTIAL)
 356                 gso_reset_checksum(seg, ~check);
 357         else
 358                 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
 359
 360         /* update refcount for the packet */
 361         if (copy_dtor) {
 362                 int delta = sum_truesize - gso_skb->truesize;
 363
 364                 /* In some pathological cases, delta can be negative.
 365                  * We need to either use refcount_add() or refcount_sub_and_test()
 366                  */
 367                 if (likely(delta >= 0))
 368                         refcount_add(delta, &sk->sk_wmem_alloc);
 369                 else
 370                         WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
 371         }
 372         return segs;
 373 }
 374 EXPORT_SYMBOL_GPL(__udp_gso_segment);
 375
 376 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 377                                          netdev_features_t features)
 378 {
 379         struct sk_buff *segs = ERR_PTR(-EINVAL);
 380         unsigned int mss;
 381         __wsum csum;
 382         struct udphdr *uh;
 383         struct iphdr *iph;
 384
 385         if (skb->encapsulation &&
 386             (skb_shinfo(skb)->gso_type &
 387              (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
 388                 segs = skb_udp_tunnel_segment(skb, features, false);
 389                 goto out;
 390         }
 391
 392         if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
 393                 goto out;
 394
 395         if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 396                 goto out;
 397
 398         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
 399                 return __udp_gso_segment(skb, features, false);
 400
 401         mss = skb_shinfo(skb)->gso_size;
 402         if (unlikely(skb->len <= mss))
 403                 goto out;
 404
 405         /* Do software UFO. Complete and fill in the UDP checksum as
 406          * HW cannot do checksum of UDP packets sent as multiple
 407          * IP fragments.
 408          */
 409
 410         uh = udp_hdr(skb);
 411         iph = ip_hdr(skb);
 412
 413         uh->check = 0;
 414         csum = skb_checksum(skb, 0, skb->len, 0);
 415         uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
 416         if (uh->check == 0)
 417                 uh->check = CSUM_MANGLED_0;
 418
 419         skb->ip_summed = CHECKSUM_UNNECESSARY;
 420
 421         /* If there is no outer header we can fake a checksum offload
 422          * due to the fact that we have already done the checksum in
 423          * software prior to segmenting the frame.
 424          */
 425         if (!skb->encap_hdr_csum)
 426                 features |= NETIF_F_HW_CSUM;
 427
 428         /* Fragment the skb. IP headers of the fragments are updated in
 429          * inet_gso_segment()
 430          */
 431         segs = skb_segment(skb, features);
 432 out:
 433         return segs;
 434 }
 435
 436 static int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
 437 {
 438         if (unlikely(p->len + skb->len >= 65536))
 439                 return -E2BIG;
 440
 441         if (NAPI_GRO_CB(p)->last == p)
 442                 skb_shinfo(p)->frag_list = skb;
 443         else
 444                 NAPI_GRO_CB(p)->last->next = skb;
 445
 446         skb_pull(skb, skb_gro_offset(skb));
 447
 448         NAPI_GRO_CB(p)->last = skb;
 449         NAPI_GRO_CB(p)->count++;
 450         p->data_len += skb->len;
 451
 452         /* sk ownership - if any - completely transferred to the aggregated packet */
 453         skb->destructor = NULL;
 454         skb->sk = NULL;
 455         p->truesize += skb->truesize;
 456         p->len += skb->len;
 457
 458         NAPI_GRO_CB(skb)->same_flow = 1;
 459
 460         return 0;
 461 }
 462
 463
 464 #define UDP_GRO_CNT_MAX 64
 465 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
 466                                                struct sk_buff *skb)
 467 {
 468         struct udphdr *uh = udp_gro_udphdr(skb);
 469         struct sk_buff *pp = NULL;
 470         struct udphdr *uh2;
 471         struct sk_buff *p;
 472         unsigned int ulen;
 473         int ret = 0;
 474
 475         /* requires non zero csum, for symmetry with GSO */
 476         if (!uh->check) {
 477                 NAPI_GRO_CB(skb)->flush = 1;
 478                 return NULL;
 479         }
 480
 481         /* Do not deal with padded or malicious packets, sorry ! */
 482         ulen = ntohs(uh->len);
 483         if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
 484                 NAPI_GRO_CB(skb)->flush = 1;
 485                 return NULL;
 486         }
 487         /* pull encapsulating udp header */
 488         skb_gro_pull(skb, sizeof(struct udphdr));
 489
 490         list_for_each_entry(p, head, list) {
 491                 if (!NAPI_GRO_CB(p)->same_flow)
 492                         continue;
 493
 494                 uh2 = udp_hdr(p);
 495
 496                 /* Match ports only, as csum is always non zero */
 497                 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
 498                         NAPI_GRO_CB(p)->same_flow = 0;
 499                         continue;
 500                 }
 501
 502                 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
 503                         NAPI_GRO_CB(skb)->flush = 1;
 504                         return p;
 505                 }
 506
 507                 /* Terminate the flow on len mismatch or if it grow "too much".
 508                  * Under small packet flood GRO count could elsewhere grow a lot
 509                  * leading to excessive truesize values.
 510                  * On len mismatch merge the first packet shorter than gso_size,
 511                  * otherwise complete the GRO packet.
 512                  */
 513                 if (ulen > ntohs(uh2->len)) {
 514                         pp = p;
 515                 } else {
 516                         if (NAPI_GRO_CB(skb)->is_flist) {
 517                                 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
 518                                         NAPI_GRO_CB(skb)->flush = 1;
 519                                         return NULL;
 520                                 }
 521                                 if ((skb->ip_summed != p->ip_summed) ||
 522                                     (skb->csum_level != p->csum_level)) {
 523                                         NAPI_GRO_CB(skb)->flush = 1;
 524                                         return NULL;
 525                                 }
 526                                 ret = skb_gro_receive_list(p, skb);
 527                         } else {
 528                                 skb_gro_postpull_rcsum(skb, uh,
 529                                                        sizeof(struct udphdr));
 530
 531                                 ret = skb_gro_receive(p, skb);
 532                         }
 533                 }
 534
 535                 if (ret || ulen != ntohs(uh2->len) ||
 536                     NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
 537                         pp = p;
 538
 539                 return pp;
 540         }
 541
 542         /* mismatch, but we never need to flush */
 543         return NULL;
 544 }
 545
 546 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 547                                 struct udphdr *uh, struct sock *sk)
 548 {
 549         struct sk_buff *pp = NULL;
 550         struct sk_buff *p;
 551         struct udphdr *uh2;
 552         unsigned int off = skb_gro_offset(skb);
 553         int flush = 1;
 554
 555         /* We can do L4 aggregation only if the packet can't land in a tunnel
 556          * otherwise we could corrupt the inner stream. Detecting such packets
 557          * cannot be foolproof and the aggregation might still happen in some
 558          * cases. Such packets should be caught in udp_unexpected_gso later.
 559          */
 560         NAPI_GRO_CB(skb)->is_flist = 0;
 561         if (!sk || !udp_sk(sk)->gro_receive) {
 562                 /* If the packet was locally encapsulated in a UDP tunnel that
 563                  * wasn't detected above, do not GRO.
 564                  */
 565                 if (skb->encapsulation)
 566                         goto out;
 567
 568                 if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
 569                         NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
 570
 571                 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
 572                     (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
 573                         return call_gro_receive(udp_gro_receive_segment, head, skb);
 574
 575                 /* no GRO, be sure flush the current packet */
 576                 goto out;
 577         }
 578
 579         if (NAPI_GRO_CB(skb)->encap_mark ||
 580             (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
 581              NAPI_GRO_CB(skb)->csum_cnt == 0 &&
 582              !NAPI_GRO_CB(skb)->csum_valid))
 583                 goto out;
 584
 585         /* mark that this skb passed once through the tunnel gro layer */
 586         NAPI_GRO_CB(skb)->encap_mark = 1;
 587
 588         flush = 0;
 589
 590         list_for_each_entry(p, head, list) {
 591                 if (!NAPI_GRO_CB(p)->same_flow)
 592                         continue;
 593
 594                 uh2 = (struct udphdr   *)(p->data + off);
 595
 596                 /* Match ports and either checksums are either both zero
 597                  * or nonzero.
 598                  */
 599                 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
 600                     (!uh->check ^ !uh2->check)) {
 601                         NAPI_GRO_CB(p)->same_flow = 0;
 602                         continue;
 603                 }
 604         }
 605
 606         skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
 607         skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
 608         pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
 609
 610 out:
 611         skb_gro_flush_final(skb, pp, flush);
 612         return pp;
 613 }
 614 EXPORT_SYMBOL(udp_gro_receive);
 615
 616 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
 617                                         __be16 dport)
 618 {
 619         const struct iphdr *iph = skb_gro_network_header(skb);
 620         struct net *net = dev_net(skb->dev);
 621         int iif, sdif;
 622
 623         inet_get_iif_sdif(skb, &iif, &sdif);
 624
 625         return __udp4_lib_lookup(net, iph->saddr, sport,
 626                                  iph->daddr, dport, iif,
 627                                  sdif, net->ipv4.udp_table, NULL);
 628 }
 629
 630 INDIRECT_CALLABLE_SCOPE
 631 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
 632 {
 633         struct udphdr *uh = udp_gro_udphdr(skb);
 634         struct sock *sk = NULL;
 635         struct sk_buff *pp;
 636
 637         if (unlikely(!uh))
 638                 goto flush;
 639
 640         /* Don't bother verifying checksum if we're going to flush anyway. */
 641         if (NAPI_GRO_CB(skb)->flush)
 642                 goto skip;
 643
 644         if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
 645                                                  inet_gro_compute_pseudo))
 646                 goto flush;
 647         else if (uh->check)
 648                 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
 649                                              inet_gro_compute_pseudo);
 650 skip:
 651         NAPI_GRO_CB(skb)->is_ipv6 = 0;
 652
 653         if (static_branch_unlikely(&udp_encap_needed_key))
 654                 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
 655
 656         pp = udp_gro_receive(head, skb, uh, sk);
 657         return pp;
 658
 659 flush:
 660         NAPI_GRO_CB(skb)->flush = 1;
 661         return NULL;
 662 }
 663
 664 static int udp_gro_complete_segment(struct sk_buff *skb)
 665 {
 666         struct udphdr *uh = udp_hdr(skb);
 667
 668         skb->csum_start = (unsigned char *)uh - skb->head;
 669         skb->csum_offset = offsetof(struct udphdr, check);
 670         skb->ip_summed = CHECKSUM_PARTIAL;
 671
 672         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 673         skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
 674
 675         if (skb->encapsulation)
 676                 skb->inner_transport_header = skb->transport_header;
 677
 678         return 0;
 679 }
 680
 681 int udp_gro_complete(struct sk_buff *skb, int nhoff,
 682                      udp_lookup_t lookup)
 683 {
 684         __be16 newlen = htons(skb->len - nhoff);
 685         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 686         struct sock *sk;
 687         int err;
 688
 689         uh->len = newlen;
 690
 691         sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
 692                                 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
 693         if (sk && udp_sk(sk)->gro_complete) {
 694                 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
 695                                         : SKB_GSO_UDP_TUNNEL;
 696
 697                 /* clear the encap mark, so that inner frag_list gro_complete
 698                  * can take place
 699                  */
 700                 NAPI_GRO_CB(skb)->encap_mark = 0;
 701
 702                 /* Set encapsulation before calling into inner gro_complete()
 703                  * functions to make them set up the inner offsets.
 704                  */
 705                 skb->encapsulation = 1;
 706                 err = udp_sk(sk)->gro_complete(sk, skb,
 707                                 nhoff + sizeof(struct udphdr));
 708         } else {
 709                 err = udp_gro_complete_segment(skb);
 710         }
 711
 712         if (skb->remcsum_offload)
 713                 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
 714
 715         return err;
 716 }
 717 EXPORT_SYMBOL(udp_gro_complete);
 718
 719 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
 720 {
 721         const struct iphdr *iph = ip_hdr(skb);
 722         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 723
 724         /* do fraglist only if there is no outer UDP encap (or we already processed it) */
 725         if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
 726                 uh->len = htons(skb->len - nhoff);
 727
 728                 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
 729                 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 730
 731                 __skb_incr_checksum_unnecessary(skb);
 732
 733                 return 0;
 734         }
 735
 736         if (uh->check)
 737                 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
 738                                           iph->daddr, 0);
 739
 740         return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
 741 }
 742
 743 static const struct net_offload udpv4_offload = {
 744         .callbacks = {
 745                 .gso_segment = udp4_ufo_fragment,
 746                 .gro_receive  = udp4_gro_receive,
 747                 .gro_complete = udp4_gro_complete,
 748         },
 749 };
 750
 751 int __init udpv4_offload_init(void)
 752 {
 753         return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
 754 }