LXR linux/net/ipv4/udp

   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
  14static 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));
 144out:
 145        return segs;
 146}
 147
 148struct 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
 180out_unlock:
 181        rcu_read_unlock();
 182
 183        return segs;
 184}
 185EXPORT_SYMBOL(skb_udp_tunnel_segment);
 186
 187static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
 188                                              netdev_features_t features)
 189{
 190        unsigned int mss = skb_shinfo(skb)->gso_size;
 191
 192        skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
 193        if (IS_ERR(skb))
 194                return skb;
 195
 196        udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
 197
 198        return skb;
 199}
 200
 201struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 202                                  netdev_features_t features)
 203{
 204        struct sock *sk = gso_skb->sk;
 205        unsigned int sum_truesize = 0;
 206        struct sk_buff *segs, *seg;
 207        struct udphdr *uh;
 208        unsigned int mss;
 209        bool copy_dtor;
 210        __sum16 check;
 211        __be16 newlen;
 212
 213        if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
 214                return __udp_gso_segment_list(gso_skb, features);
 215
 216        mss = skb_shinfo(gso_skb)->gso_size;
 217        if (gso_skb->len <= sizeof(*uh) + mss)
 218                return ERR_PTR(-EINVAL);
 219
 220        skb_pull(gso_skb, sizeof(*uh));
 221
 222        /* clear destructor to avoid skb_segment assigning it to tail */
 223        copy_dtor = gso_skb->destructor == sock_wfree;
 224        if (copy_dtor)
 225                gso_skb->destructor = NULL;
 226
 227        segs = skb_segment(gso_skb, features);
 228        if (IS_ERR_OR_NULL(segs)) {
 229                if (copy_dtor)
 230                        gso_skb->destructor = sock_wfree;
 231                return segs;
 232        }
 233
 234        /* GSO partial and frag_list segmentation only requires splitting
 235         * the frame into an MSS multiple and possibly a remainder, both
 236         * cases return a GSO skb. So update the mss now.
 237         */
 238        if (skb_is_gso(segs))
 239                mss *= skb_shinfo(segs)->gso_segs;
 240
 241        seg = segs;
 242        uh = udp_hdr(seg);
 243
 244        /* preserve TX timestamp flags and TS key for first segment */
 245        skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
 246        skb_shinfo(seg)->tx_flags |=
 247                        (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
 248
 249        /* compute checksum adjustment based on old length versus new */
 250        newlen = htons(sizeof(*uh) + mss);
 251        check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 252
 253        for (;;) {
 254                if (copy_dtor) {
 255                        seg->destructor = sock_wfree;
 256                        seg->sk = sk;
 257                        sum_truesize += seg->truesize;
 258                }
 259
 260                if (!seg->next)
 261                        break;
 262
 263                uh->len = newlen;
 264                uh->check = check;
 265
 266                if (seg->ip_summed == CHECKSUM_PARTIAL)
 267                        gso_reset_checksum(seg, ~check);
 268                else
 269                        uh->check = gso_make_checksum(seg, ~check) ? :
 270                                    CSUM_MANGLED_0;
 271
 272                seg = seg->next;
 273                uh = udp_hdr(seg);
 274        }
 275
 276        /* last packet can be partial gso_size, account for that in checksum */
 277        newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
 278                       seg->data_len);
 279        check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 280
 281        uh->len = newlen;
 282        uh->check = check;
 283
 284        if (seg->ip_summed == CHECKSUM_PARTIAL)
 285                gso_reset_checksum(seg, ~check);
 286        else
 287                uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
 288
 289        /* update refcount for the packet */
 290        if (copy_dtor) {
 291                int delta = sum_truesize - gso_skb->truesize;
 292
 293                /* In some pathological cases, delta can be negative.
 294                 * We need to either use refcount_add() or refcount_sub_and_test()
 295                 */
 296                if (likely(delta >= 0))
 297                        refcount_add(delta, &sk->sk_wmem_alloc);
 298                else
 299                        WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
 300        }
 301        return segs;
 302}
 303EXPORT_SYMBOL_GPL(__udp_gso_segment);
 304
 305static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 306                                         netdev_features_t features)
 307{
 308        struct sk_buff *segs = ERR_PTR(-EINVAL);
 309        unsigned int mss;
 310        __wsum csum;
 311        struct udphdr *uh;
 312        struct iphdr *iph;
 313
 314        if (skb->encapsulation &&
 315            (skb_shinfo(skb)->gso_type &
 316             (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
 317                segs = skb_udp_tunnel_segment(skb, features, false);
 318                goto out;
 319        }
 320
 321        if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
 322                goto out;
 323
 324        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 325                goto out;
 326
 327        if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
 328                return __udp_gso_segment(skb, features);
 329
 330        mss = skb_shinfo(skb)->gso_size;
 331        if (unlikely(skb->len <= mss))
 332                goto out;
 333
 334        /* Do software UFO. Complete and fill in the UDP checksum as
 335         * HW cannot do checksum of UDP packets sent as multiple
 336         * IP fragments.
 337         */
 338
 339        uh = udp_hdr(skb);
 340        iph = ip_hdr(skb);
 341
 342        uh->check = 0;
 343        csum = skb_checksum(skb, 0, skb->len, 0);
 344        uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
 345        if (uh->check == 0)
 346                uh->check = CSUM_MANGLED_0;
 347
 348        skb->ip_summed = CHECKSUM_UNNECESSARY;
 349
 350        /* If there is no outer header we can fake a checksum offload
 351         * due to the fact that we have already done the checksum in
 352         * software prior to segmenting the frame.
 353         */
 354        if (!skb->encap_hdr_csum)
 355                features |= NETIF_F_HW_CSUM;
 356
 357        /* Fragment the skb. IP headers of the fragments are updated in
 358         * inet_gso_segment()
 359         */
 360        segs = skb_segment(skb, features);
 361out:
 362        return segs;
 363}
 364
 365#define UDP_GRO_CNT_MAX 64
 366static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
 367                                               struct sk_buff *skb)
 368{
 369        struct udphdr *uh = udp_hdr(skb);
 370        struct sk_buff *pp = NULL;
 371        struct udphdr *uh2;
 372        struct sk_buff *p;
 373        unsigned int ulen;
 374        int ret = 0;
 375
 376        /* requires non zero csum, for symmetry with GSO */
 377        if (!uh->check) {
 378                NAPI_GRO_CB(skb)->flush = 1;
 379                return NULL;
 380        }
 381
 382        /* Do not deal with padded or malicious packets, sorry ! */
 383        ulen = ntohs(uh->len);
 384        if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
 385                NAPI_GRO_CB(skb)->flush = 1;
 386                return NULL;
 387        }
 388        /* pull encapsulating udp header */
 389        skb_gro_pull(skb, sizeof(struct udphdr));
 390
 391        list_for_each_entry(p, head, list) {
 392                if (!NAPI_GRO_CB(p)->same_flow)
 393                        continue;
 394
 395                uh2 = udp_hdr(p);
 396
 397                /* Match ports only, as csum is always non zero */
 398                if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
 399                        NAPI_GRO_CB(p)->same_flow = 0;
 400                        continue;
 401                }
 402
 403                if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
 404                        NAPI_GRO_CB(skb)->flush = 1;
 405                        return p;
 406                }
 407
 408                /* Terminate the flow on len mismatch or if it grow "too much".
 409                 * Under small packet flood GRO count could elsewhere grow a lot
 410                 * leading to excessive truesize values.
 411                 * On len mismatch merge the first packet shorter than gso_size,
 412                 * otherwise complete the GRO packet.
 413                 */
 414                if (ulen > ntohs(uh2->len)) {
 415                        pp = p;
 416                } else {
 417                        if (NAPI_GRO_CB(skb)->is_flist) {
 418                                if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
 419                                        NAPI_GRO_CB(skb)->flush = 1;
 420                                        return NULL;
 421                                }
 422                                if ((skb->ip_summed != p->ip_summed) ||
 423                                    (skb->csum_level != p->csum_level)) {
 424                                        NAPI_GRO_CB(skb)->flush = 1;
 425                                        return NULL;
 426                                }
 427                                ret = skb_gro_receive_list(p, skb);
 428                        } else {
 429                                skb_gro_postpull_rcsum(skb, uh,
 430                                                       sizeof(struct udphdr));
 431
 432                                ret = skb_gro_receive(p, skb);
 433                        }
 434                }
 435
 436                if (ret || ulen != ntohs(uh2->len) ||
 437                    NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
 438                        pp = p;
 439
 440                return pp;
 441        }
 442
 443        /* mismatch, but we never need to flush */
 444        return NULL;
 445}
 446
 447struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 448                                struct udphdr *uh, struct sock *sk)
 449{
 450        struct sk_buff *pp = NULL;
 451        struct sk_buff *p;
 452        struct udphdr *uh2;
 453        unsigned int off = skb_gro_offset(skb);
 454        int flush = 1;
 455
 456        NAPI_GRO_CB(skb)->is_flist = 0;
 457        if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
 458                NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;
 459
 460        if ((sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist) {
 461                pp = call_gro_receive(udp_gro_receive_segment, head, skb);
 462                return pp;
 463        }
 464
 465        if (!sk || NAPI_GRO_CB(skb)->encap_mark ||
 466            (skb->ip_summed != CHECKSUM_PARTIAL &&
 467             NAPI_GRO_CB(skb)->csum_cnt == 0 &&
 468             !NAPI_GRO_CB(skb)->csum_valid) ||
 469            !udp_sk(sk)->gro_receive)
 470                goto out;
 471
 472        /* mark that this skb passed once through the tunnel gro layer */
 473        NAPI_GRO_CB(skb)->encap_mark = 1;
 474
 475        flush = 0;
 476
 477        list_for_each_entry(p, head, list) {
 478                if (!NAPI_GRO_CB(p)->same_flow)
 479                        continue;
 480
 481                uh2 = (struct udphdr   *)(p->data + off);
 482
 483                /* Match ports and either checksums are either both zero
 484                 * or nonzero.
 485                 */
 486                if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
 487                    (!uh->check ^ !uh2->check)) {
 488                        NAPI_GRO_CB(p)->same_flow = 0;
 489                        continue;
 490                }
 491        }
 492
 493        skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
 494        skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
 495        pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
 496
 497out:
 498        skb_gro_flush_final(skb, pp, flush);
 499        return pp;
 500}
 501EXPORT_SYMBOL(udp_gro_receive);
 502
 503INDIRECT_CALLABLE_SCOPE
 504struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
 505{
 506        struct udphdr *uh = udp_gro_udphdr(skb);
 507        struct sk_buff *pp;
 508        struct sock *sk;
 509
 510        if (unlikely(!uh))
 511                goto flush;
 512
 513        /* Don't bother verifying checksum if we're going to flush anyway. */
 514        if (NAPI_GRO_CB(skb)->flush)
 515                goto skip;
 516
 517        if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
 518                                                 inet_gro_compute_pseudo))
 519                goto flush;
 520        else if (uh->check)
 521                skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
 522                                             inet_gro_compute_pseudo);
 523skip:
 524        NAPI_GRO_CB(skb)->is_ipv6 = 0;
 525        rcu_read_lock();
 526        sk = static_branch_unlikely(&udp_encap_needed_key) ? udp4_lib_lookup_skb(skb, uh->source, uh->dest) : NULL;
 527        pp = udp_gro_receive(head, skb, uh, sk);
 528        rcu_read_unlock();
 529        return pp;
 530
 531flush:
 532        NAPI_GRO_CB(skb)->flush = 1;
 533        return NULL;
 534}
 535
 536static int udp_gro_complete_segment(struct sk_buff *skb)
 537{
 538        struct udphdr *uh = udp_hdr(skb);
 539
 540        skb->csum_start = (unsigned char *)uh - skb->head;
 541        skb->csum_offset = offsetof(struct udphdr, check);
 542        skb->ip_summed = CHECKSUM_PARTIAL;
 543
 544        skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 545        skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
 546        return 0;
 547}
 548
 549int udp_gro_complete(struct sk_buff *skb, int nhoff,
 550                     udp_lookup_t lookup)
 551{
 552        __be16 newlen = htons(skb->len - nhoff);
 553        struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 554        int err = -ENOSYS;
 555        struct sock *sk;
 556
 557        uh->len = newlen;
 558
 559        rcu_read_lock();
 560        sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
 561                                udp4_lib_lookup_skb, skb, uh->source, uh->dest);
 562        if (sk && udp_sk(sk)->gro_complete) {
 563                skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
 564                                        : SKB_GSO_UDP_TUNNEL;
 565
 566                /* Set encapsulation before calling into inner gro_complete()
 567                 * functions to make them set up the inner offsets.
 568                 */
 569                skb->encapsulation = 1;
 570                err = udp_sk(sk)->gro_complete(sk, skb,
 571                                nhoff + sizeof(struct udphdr));
 572        } else {
 573                err = udp_gro_complete_segment(skb);
 574        }
 575        rcu_read_unlock();
 576
 577        if (skb->remcsum_offload)
 578                skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
 579
 580        return err;
 581}
 582EXPORT_SYMBOL(udp_gro_complete);
 583
 584INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
 585{
 586        const struct iphdr *iph = ip_hdr(skb);
 587        struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 588
 589        if (NAPI_GRO_CB(skb)->is_flist) {
 590                uh->len = htons(skb->len - nhoff);
 591
 592                skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
 593                skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 594
 595                if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 596                        if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
 597                                skb->csum_level++;
 598                } else {
 599                        skb->ip_summed = CHECKSUM_UNNECESSARY;
 600                        skb->csum_level = 0;
 601                }
 602
 603                return 0;
 604        }
 605
 606        if (uh->check)
 607                uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
 608                                          iph->daddr, 0);
 609
 610        return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
 611}
 612
 613static const struct net_offload udpv4_offload = {
 614        .callbacks = {
 615                .gso_segment = udp4_ufo_fragment,
 616                .gro_receive  = udp4_gro_receive,
 617                .gro_complete = udp4_gro_complete,
 618        },
 619};
 620
 621int __init udpv4_offload_init(void)
 622{
 623        return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
 624}
 625