net/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/udp.h>
  11 #include <net/protocol.h>
  12 #include <net/inet_common.h>
  13
  14 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
  15         netdev_features_t features,
  16         struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
  17                                              netdev_features_t features),
  18         __be16 new_protocol, bool is_ipv6)
  19 {
  20         int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
  21         bool remcsum, need_csum, offload_csum, gso_partial;
  22         struct sk_buff *segs = ERR_PTR(-EINVAL);
  23         struct udphdr *uh = udp_hdr(skb);
  24         u16 mac_offset = skb->mac_header;
  25         __be16 protocol = skb->protocol;
  26         u16 mac_len = skb->mac_len;
  27         int udp_offset, outer_hlen;
  28         __wsum partial;
  29         bool need_ipsec;
  30
  31         if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
  32                 goto out;
  33
  34         /* Adjust partial header checksum to negate old length.
  35          * We cannot rely on the value contained in uh->len as it is
  36          * possible that the actual value exceeds the boundaries of the
  37          * 16 bit length field due to the header being added outside of an
  38          * IP or IPv6 frame that was already limited to 64K - 1.
  39          */
  40         if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
  41                 partial = (__force __wsum)uh->len;
  42         else
  43                 partial = (__force __wsum)htonl(skb->len);
  44         partial = csum_sub(csum_unfold(uh->check), partial);
  45
  46         /* setup inner skb. */
  47         skb->encapsulation = 0;
  48         SKB_GSO_CB(skb)->encap_level = 0;
  49         __skb_pull(skb, tnl_hlen);
  50         skb_reset_mac_header(skb);
  51         skb_set_network_header(skb, skb_inner_network_offset(skb));
  52         skb->mac_len = skb_inner_network_offset(skb);
  53         skb->protocol = new_protocol;
  54
  55         need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
  56         skb->encap_hdr_csum = need_csum;
  57
  58         remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
  59         skb->remcsum_offload = remcsum;
  60
  61         need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
  62         /* Try to offload checksum if possible */
  63         offload_csum = !!(need_csum &&
  64                           !need_ipsec &&
  65                           (skb->dev->features &
  66                            (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
  67                                       (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
  68
  69         features &= skb->dev->hw_enc_features;
  70
  71         /* The only checksum offload we care about from here on out is the
  72          * outer one so strip the existing checksum feature flags and
  73          * instead set the flag based on our outer checksum offload value.
  74          */
  75         if (remcsum) {
  76                 features &= ~NETIF_F_CSUM_MASK;
  77                 if (!need_csum || offload_csum)
  78                         features |= NETIF_F_HW_CSUM;
  79         }
  80
  81         /* segment inner packet. */
  82         segs = gso_inner_segment(skb, features);
  83         if (IS_ERR_OR_NULL(segs)) {
  84                 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
  85                                      mac_len);
  86                 goto out;
  87         }
  88
  89         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
  90
  91         outer_hlen = skb_tnl_header_len(skb);
  92         udp_offset = outer_hlen - tnl_hlen;
  93         skb = segs;
  94         do {
  95                 unsigned int len;
  96
  97                 if (remcsum)
  98                         skb->ip_summed = CHECKSUM_NONE;
  99
 100                 /* Set up inner headers if we are offloading inner checksum */
 101                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 102                         skb_reset_inner_headers(skb);
 103                         skb->encapsulation = 1;
 104                 }
 105
 106                 skb->mac_len = mac_len;
 107                 skb->protocol = protocol;
 108
 109                 __skb_push(skb, outer_hlen);
 110                 skb_reset_mac_header(skb);
 111                 skb_set_network_header(skb, mac_len);
 112                 skb_set_transport_header(skb, udp_offset);
 113                 len = skb->len - udp_offset;
 114                 uh = udp_hdr(skb);
 115
 116                 /* If we are only performing partial GSO the inner header
 117                  * will be using a length value equal to only one MSS sized
 118                  * segment instead of the entire frame.
 119                  */
 120                 if (gso_partial && skb_is_gso(skb)) {
 121                         uh->len = htons(skb_shinfo(skb)->gso_size +
 122                                         SKB_GSO_CB(skb)->data_offset +
 123                                         skb->head - (unsigned char *)uh);
 124                 } else {
 125                         uh->len = htons(len);
 126                 }
 127
 128                 if (!need_csum)
 129                         continue;
 130
 131                 uh->check = ~csum_fold(csum_add(partial,
 132                                        (__force __wsum)htonl(len)));
 133
 134                 if (skb->encapsulation || !offload_csum) {
 135                         uh->check = gso_make_checksum(skb, ~uh->check);
 136                         if (uh->check == 0)
 137                                 uh->check = CSUM_MANGLED_0;
 138                 } else {
 139                         skb->ip_summed = CHECKSUM_PARTIAL;
 140                         skb->csum_start = skb_transport_header(skb) - skb->head;
 141                         skb->csum_offset = offsetof(struct udphdr, check);
 142                 }
 143         } while ((skb = skb->next));
 144 out:
 145         return segs;
 146 }
 147
 148 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 149                                        netdev_features_t features,
 150                                        bool is_ipv6)
 151 {
 152         __be16 protocol = skb->protocol;
 153         const struct net_offload **offloads;
 154         const struct net_offload *ops;
 155         struct sk_buff *segs = ERR_PTR(-EINVAL);
 156         struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
 157                                              netdev_features_t features);
 158
 159         rcu_read_lock();
 160
 161         switch (skb->inner_protocol_type) {
 162         case ENCAP_TYPE_ETHER:
 163                 protocol = skb->inner_protocol;
 164                 gso_inner_segment = skb_mac_gso_segment;
 165                 break;
 166         case ENCAP_TYPE_IPPROTO:
 167                 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
 168                 ops = rcu_dereference(offloads[skb->inner_ipproto]);
 169                 if (!ops || !ops->callbacks.gso_segment)
 170                         goto out_unlock;
 171                 gso_inner_segment = ops->callbacks.gso_segment;
 172                 break;
 173         default:
 174                 goto out_unlock;
 175         }
 176
 177         segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
 178                                         protocol, is_ipv6);
 179
 180 out_unlock:
 181         rcu_read_unlock();
 182
 183         return segs;
 184 }
 185 EXPORT_SYMBOL(skb_udp_tunnel_segment);
 186
 187 static void __udpv4_gso_segment_csum(struct sk_buff *seg,
 188                                      __be32 *oldip, __be32 *newip,
 189                                      __be16 *oldport, __be16 *newport)
 190 {
 191         struct udphdr *uh;
 192         struct iphdr *iph;
 193
 194         if (*oldip == *newip && *oldport == *newport)
 195                 return;
 196
 197         uh = udp_hdr(seg);
 198         iph = ip_hdr(seg);
 199
 200         if (uh->check) {
 201                 inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
 202                                          true);
 203                 inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
 204                                          false);
 205                 if (!uh->check)
 206                         uh->check = CSUM_MANGLED_0;
 207         }
 208         *oldport = *newport;
 209
 210         csum_replace4(&iph->check, *oldip, *newip);
 211         *oldip = *newip;
 212 }
 213
 214 static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
 215 {
 216         struct sk_buff *seg;
 217         struct udphdr *uh, *uh2;
 218         struct iphdr *iph, *iph2;
 219
 220         seg = segs;
 221         uh = udp_hdr(seg);
 222         iph = ip_hdr(seg);
 223
 224         if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
 225             (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
 226             (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
 227             (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
 228                 return segs;
 229
 230         while ((seg = seg->next)) {
 231                 uh2 = udp_hdr(seg);
 232                 iph2 = ip_hdr(seg);
 233
 234                 __udpv4_gso_segment_csum(seg,
 235                                          &iph2->saddr, &iph->saddr,
 236                                          &uh2->source, &uh->source);
 237                 __udpv4_gso_segment_csum(seg,
 238                                          &iph2->daddr, &iph->daddr,
 239                                          &uh2->dest, &uh->dest);
 240         }
 241
 242         return segs;
 243 }
 244
 245 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
 246                                               netdev_features_t features,
 247                                               bool is_ipv6)
 248 {
 249         unsigned int mss = skb_shinfo(skb)->gso_size;
 250
 251         skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
 252         if (IS_ERR(skb))
 253                 return skb;
 254
 255         udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
 256
 257         return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
 258 }
 259
 260 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 261                                   netdev_features_t features, bool is_ipv6)
 262 {
 263         struct sock *sk = gso_skb->sk;
 264         unsigned int sum_truesize = 0;
 265         struct sk_buff *segs, *seg;
 266         struct udphdr *uh;
 267         unsigned int mss;
 268         bool copy_dtor;
 269         __sum16 check;
 270         __be16 newlen;
 271
 272         if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
 273                 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
 274
 275         mss = skb_shinfo(gso_skb)->gso_size;
 276         if (gso_skb->len <= sizeof(*uh) + mss)
 277                 return ERR_PTR(-EINVAL);
 278
 279         skb_pull(gso_skb, sizeof(*uh));
 280
 281         /* clear destructor to avoid skb_segment assigning it to tail */
 282         copy_dtor = gso_skb->destructor == sock_wfree;
 283         if (copy_dtor)
 284                 gso_skb->destructor = NULL;
 285
 286         segs = skb_segment(gso_skb, features);
 287         if (IS_ERR_OR_NULL(segs)) {
 288                 if (copy_dtor)
 289                         gso_skb->destructor = sock_wfree;
 290                 return segs;
 291         }
 292
 293         /* GSO partial and frag_list segmentation only requires splitting
 294          * the frame into an MSS multiple and possibly a remainder, both
 295          * cases return a GSO skb. So update the mss now.
 296          */
 297         if (skb_is_gso(segs))
 298                 mss *= skb_shinfo(segs)->gso_segs;
 299
 300         seg = segs;
 301         uh = udp_hdr(seg);
 302
 303         /* preserve TX timestamp flags and TS key for first segment */
 304         skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
 305         skb_shinfo(seg)->tx_flags |=
 306                         (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
 307
 308         /* compute checksum adjustment based on old length versus new */
 309         newlen = htons(sizeof(*uh) + mss);
 310         check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 311
 312         for (;;) {
 313                 if (copy_dtor) {
 314                         seg->destructor = sock_wfree;
 315                         seg->sk = sk;
 316                         sum_truesize += seg->truesize;
 317                 }
 318
 319                 if (!seg->next)
 320                         break;
 321
 322                 uh->len = newlen;
 323                 uh->check = check;
 324
 325                 if (seg->ip_summed == CHECKSUM_PARTIAL)
 326                         gso_reset_checksum(seg, ~check);
 327                 else
 328                         uh->check = gso_make_checksum(seg, ~check) ? :
 329                                     CSUM_MANGLED_0;
 330
 331                 seg = seg->next;
 332                 uh = udp_hdr(seg);
 333         }
 334
 335         /* last packet can be partial gso_size, account for that in checksum */
 336         newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
 337                        seg->data_len);
 338         check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 339
 340         uh->len = newlen;
 341         uh->check = check;
 342
 343         if (seg->ip_summed == CHECKSUM_PARTIAL)
 344                 gso_reset_checksum(seg, ~check);
 345         else
 346                 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
 347
 348         /* update refcount for the packet */
 349         if (copy_dtor) {
 350                 int delta = sum_truesize - gso_skb->truesize;
 351
 352                 /* In some pathological cases, delta can be negative.
 353                  * We need to either use refcount_add() or refcount_sub_and_test()
 354                  */
 355                 if (likely(delta >= 0))
 356                         refcount_add(delta, &sk->sk_wmem_alloc);
 357                 else
 358                         WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
 359         }
 360         return segs;
 361 }
 362 EXPORT_SYMBOL_GPL(__udp_gso_segment);
 363
 364 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 365                                          netdev_features_t features)
 366 {
 367         struct sk_buff *segs = ERR_PTR(-EINVAL);
 368         unsigned int mss;
 369         __wsum csum;
 370         struct udphdr *uh;
 371         struct iphdr *iph;
 372
 373         if (skb->encapsulation &&
 374             (skb_shinfo(skb)->gso_type &
 375              (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
 376                 segs = skb_udp_tunnel_segment(skb, features, false);
 377                 goto out;
 378         }
 379
 380         if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
 381                 goto out;
 382
 383         if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 384                 goto out;
 385
 386         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
 387                 return __udp_gso_segment(skb, features, false);
 388
 389         mss = skb_shinfo(skb)->gso_size;
 390         if (unlikely(skb->len <= mss))
 391                 goto out;
 392
 393         /* Do software UFO. Complete and fill in the UDP checksum as
 394          * HW cannot do checksum of UDP packets sent as multiple
 395          * IP fragments.
 396          */
 397
 398         uh = udp_hdr(skb);
 399         iph = ip_hdr(skb);
 400
 401         uh->check = 0;
 402         csum = skb_checksum(skb, 0, skb->len, 0);
 403         uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
 404         if (uh->check == 0)
 405                 uh->check = CSUM_MANGLED_0;
 406
 407         skb->ip_summed = CHECKSUM_UNNECESSARY;
 408
 409         /* If there is no outer header we can fake a checksum offload
 410          * due to the fact that we have already done the checksum in
 411          * software prior to segmenting the frame.
 412          */
 413         if (!skb->encap_hdr_csum)
 414                 features |= NETIF_F_HW_CSUM;
 415
 416         /* Fragment the skb. IP headers of the fragments are updated in
 417          * inet_gso_segment()
 418          */
 419         segs = skb_segment(skb, features);
 420 out:
 421         return segs;
 422 }
 423
 424 #define UDP_GRO_CNT_MAX 64
 425 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
 426                                                struct sk_buff *skb)
 427 {
 428         struct udphdr *uh = udp_gro_udphdr(skb);
 429         struct sk_buff *pp = NULL;
 430         struct udphdr *uh2;
 431         struct sk_buff *p;
 432         unsigned int ulen;
 433         int ret = 0;
 434
 435         /* requires non zero csum, for symmetry with GSO */
 436         if (!uh->check) {
 437                 NAPI_GRO_CB(skb)->flush = 1;
 438                 return NULL;
 439         }
 440
 441         /* Do not deal with padded or malicious packets, sorry ! */
 442         ulen = ntohs(uh->len);
 443         if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
 444                 NAPI_GRO_CB(skb)->flush = 1;
 445                 return NULL;
 446         }
 447         /* pull encapsulating udp header */
 448         skb_gro_pull(skb, sizeof(struct udphdr));
 449
 450         list_for_each_entry(p, head, list) {
 451                 if (!NAPI_GRO_CB(p)->same_flow)
 452                         continue;
 453
 454                 uh2 = udp_hdr(p);
 455
 456                 /* Match ports only, as csum is always non zero */
 457                 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
 458                         NAPI_GRO_CB(p)->same_flow = 0;
 459                         continue;
 460                 }
 461
 462                 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
 463                         NAPI_GRO_CB(skb)->flush = 1;
 464                         return p;
 465                 }
 466
 467                 /* Terminate the flow on len mismatch or if it grow "too much".
 468                  * Under small packet flood GRO count could elsewhere grow a lot
 469                  * leading to excessive truesize values.
 470                  * On len mismatch merge the first packet shorter than gso_size,
 471                  * otherwise complete the GRO packet.
 472                  */
 473                 if (ulen > ntohs(uh2->len)) {
 474                         pp = p;
 475                 } else {
 476                         if (NAPI_GRO_CB(skb)->is_flist) {
 477                                 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
 478                                         NAPI_GRO_CB(skb)->flush = 1;
 479                                         return NULL;
 480                                 }
 481                                 if ((skb->ip_summed != p->ip_summed) ||
 482                                     (skb->csum_level != p->csum_level)) {
 483                                         NAPI_GRO_CB(skb)->flush = 1;
 484                                         return NULL;
 485                                 }
 486                                 ret = skb_gro_receive_list(p, skb);
 487                         } else {
 488                                 skb_gro_postpull_rcsum(skb, uh,
 489                                                        sizeof(struct udphdr));
 490
 491                                 ret = skb_gro_receive(p, skb);
 492                         }
 493                 }
 494
 495                 if (ret || ulen != ntohs(uh2->len) ||
 496                     NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
 497                         pp = p;
 498
 499                 return pp;
 500         }
 501
 502         /* mismatch, but we never need to flush */
 503         return NULL;
 504 }
 505
 506 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 507                                 struct udphdr *uh, struct sock *sk)
 508 {
 509         struct sk_buff *pp = NULL;
 510         struct sk_buff *p;
 511         struct udphdr *uh2;
 512         unsigned int off = skb_gro_offset(skb);
 513         int flush = 1;
 514
 515         NAPI_GRO_CB(skb)->is_flist = 0;
 516         if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
 517                 NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;
 518
 519         if ((sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist) {
 520                 pp = call_gro_receive(udp_gro_receive_segment, head, skb);
 521                 return pp;
 522         }
 523
 524         if (!sk || NAPI_GRO_CB(skb)->encap_mark ||
 525             (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
 526              NAPI_GRO_CB(skb)->csum_cnt == 0 &&
 527              !NAPI_GRO_CB(skb)->csum_valid) ||
 528             !udp_sk(sk)->gro_receive)
 529                 goto out;
 530
 531         /* mark that this skb passed once through the tunnel gro layer */
 532         NAPI_GRO_CB(skb)->encap_mark = 1;
 533
 534         flush = 0;
 535
 536         list_for_each_entry(p, head, list) {
 537                 if (!NAPI_GRO_CB(p)->same_flow)
 538                         continue;
 539
 540                 uh2 = (struct udphdr   *)(p->data + off);
 541
 542                 /* Match ports and either checksums are either both zero
 543                  * or nonzero.
 544                  */
 545                 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
 546                     (!uh->check ^ !uh2->check)) {
 547                         NAPI_GRO_CB(p)->same_flow = 0;
 548                         continue;
 549                 }
 550         }
 551
 552         skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
 553         skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
 554         pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
 555
 556 out:
 557         skb_gro_flush_final(skb, pp, flush);
 558         return pp;
 559 }
 560 EXPORT_SYMBOL(udp_gro_receive);
 561
 562 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
 563                                         __be16 dport)
 564 {
 565         const struct iphdr *iph = skb_gro_network_header(skb);
 566
 567         return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
 568                                  iph->daddr, dport, inet_iif(skb),
 569                                  inet_sdif(skb), &udp_table, NULL);
 570 }
 571
 572 INDIRECT_CALLABLE_SCOPE
 573 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
 574 {
 575         struct udphdr *uh = udp_gro_udphdr(skb);
 576         struct sock *sk = NULL;
 577         struct sk_buff *pp;
 578
 579         if (unlikely(!uh))
 580                 goto flush;
 581
 582         /* Don't bother verifying checksum if we're going to flush anyway. */
 583         if (NAPI_GRO_CB(skb)->flush)
 584                 goto skip;
 585
 586         if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
 587                                                  inet_gro_compute_pseudo))
 588                 goto flush;
 589         else if (uh->check)
 590                 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
 591                                              inet_gro_compute_pseudo);
 592 skip:
 593         NAPI_GRO_CB(skb)->is_ipv6 = 0;
 594         rcu_read_lock();
 595
 596         if (static_branch_unlikely(&udp_encap_needed_key))
 597                 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
 598
 599         pp = udp_gro_receive(head, skb, uh, sk);
 600         rcu_read_unlock();
 601         return pp;
 602
 603 flush:
 604         NAPI_GRO_CB(skb)->flush = 1;
 605         return NULL;
 606 }
 607
 608 static int udp_gro_complete_segment(struct sk_buff *skb)
 609 {
 610         struct udphdr *uh = udp_hdr(skb);
 611
 612         skb->csum_start = (unsigned char *)uh - skb->head;
 613         skb->csum_offset = offsetof(struct udphdr, check);
 614         skb->ip_summed = CHECKSUM_PARTIAL;
 615
 616         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 617         skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
 618
 619         if (skb->encapsulation)
 620                 skb->inner_transport_header = skb->transport_header;
 621
 622         return 0;
 623 }
 624
 625 int udp_gro_complete(struct sk_buff *skb, int nhoff,
 626                      udp_lookup_t lookup)
 627 {
 628         __be16 newlen = htons(skb->len - nhoff);
 629         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 630         int err = -ENOSYS;
 631         struct sock *sk;
 632
 633         uh->len = newlen;
 634
 635         rcu_read_lock();
 636         sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
 637                                 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
 638         if (sk && udp_sk(sk)->gro_complete) {
 639                 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
 640                                         : SKB_GSO_UDP_TUNNEL;
 641
 642                 /* Set encapsulation before calling into inner gro_complete()
 643                  * functions to make them set up the inner offsets.
 644                  */
 645                 skb->encapsulation = 1;
 646                 err = udp_sk(sk)->gro_complete(sk, skb,
 647                                 nhoff + sizeof(struct udphdr));
 648         } else {
 649                 err = udp_gro_complete_segment(skb);
 650         }
 651         rcu_read_unlock();
 652
 653         if (skb->remcsum_offload)
 654                 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
 655
 656         return err;
 657 }
 658 EXPORT_SYMBOL(udp_gro_complete);
 659
 660 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
 661 {
 662         const struct iphdr *iph = ip_hdr(skb);
 663         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 664
 665         if (NAPI_GRO_CB(skb)->is_flist) {
 666                 uh->len = htons(skb->len - nhoff);
 667
 668                 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
 669                 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 670
 671                 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 672                         if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
 673                                 skb->csum_level++;
 674                 } else {
 675                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 676                         skb->csum_level = 0;
 677                 }
 678
 679                 return 0;
 680         }
 681
 682         if (uh->check)
 683                 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
 684                                           iph->daddr, 0);
 685
 686         return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
 687 }
 688
 689 static const struct net_offload udpv4_offload = {
 690         .callbacks = {
 691                 .gso_segment = udp4_ufo_fragment,
 692                 .gro_receive  = udp4_gro_receive,
 693                 .gro_complete = udp4_gro_complete,
 694         },
 695 };
 696
 697 int __init udpv4_offload_init(void)
 698 {
 699         return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
 700 }