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/gro.h>
  11 #include <net/udp.h>
  12 #include <net/protocol.h>
  13 #include <net/inet_common.h>
  14
  15 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
  16         netdev_features_t features,
  17         struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
  18                                              netdev_features_t features),
  19         __be16 new_protocol, bool is_ipv6)
  20 {
  21         int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
  22         bool remcsum, need_csum, offload_csum, gso_partial;
  23         struct sk_buff *segs = ERR_PTR(-EINVAL);
  24         struct udphdr *uh = udp_hdr(skb);
  25         u16 mac_offset = skb->mac_header;
  26         __be16 protocol = skb->protocol;
  27         u16 mac_len = skb->mac_len;
  28         int udp_offset, outer_hlen;
  29         __wsum partial;
  30         bool need_ipsec;
  31
  32         if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
  33                 goto out;
  34
  35         /* Adjust partial header checksum to negate old length.
  36          * We cannot rely on the value contained in uh->len as it is
  37          * possible that the actual value exceeds the boundaries of the
  38          * 16 bit length field due to the header being added outside of an
  39          * IP or IPv6 frame that was already limited to 64K - 1.
  40          */
  41         if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
  42                 partial = (__force __wsum)uh->len;
  43         else
  44                 partial = (__force __wsum)htonl(skb->len);
  45         partial = csum_sub(csum_unfold(uh->check), partial);
  46
  47         /* setup inner skb. */
  48         skb->encapsulation = 0;
  49         SKB_GSO_CB(skb)->encap_level = 0;
  50         __skb_pull(skb, tnl_hlen);
  51         skb_reset_mac_header(skb);
  52         skb_set_network_header(skb, skb_inner_network_offset(skb));
  53         skb_set_transport_header(skb, skb_inner_transport_offset(skb));
  54         skb->mac_len = skb_inner_network_offset(skb);
  55         skb->protocol = new_protocol;
  56
  57         need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
  58         skb->encap_hdr_csum = need_csum;
  59
  60         remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
  61         skb->remcsum_offload = remcsum;
  62
  63         need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
  64         /* Try to offload checksum if possible */
  65         offload_csum = !!(need_csum &&
  66                           !need_ipsec &&
  67                           (skb->dev->features &
  68                            (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
  69                                       (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
  70
  71         features &= skb->dev->hw_enc_features;
  72         if (need_csum)
  73                 features &= ~NETIF_F_SCTP_CRC;
  74
  75         /* The only checksum offload we care about from here on out is the
  76          * outer one so strip the existing checksum feature flags and
  77          * instead set the flag based on our outer checksum offload value.
  78          */
  79         if (remcsum) {
  80                 features &= ~NETIF_F_CSUM_MASK;
  81                 if (!need_csum || offload_csum)
  82                         features |= NETIF_F_HW_CSUM;
  83         }
  84
  85         /* segment inner packet. */
  86         segs = gso_inner_segment(skb, features);
  87         if (IS_ERR_OR_NULL(segs)) {
  88                 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
  89                                      mac_len);
  90                 goto out;
  91         }
  92
  93         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
  94
  95         outer_hlen = skb_tnl_header_len(skb);
  96         udp_offset = outer_hlen - tnl_hlen;
  97         skb = segs;
  98         do {
  99                 unsigned int len;
 100
 101                 if (remcsum)
 102                         skb->ip_summed = CHECKSUM_NONE;
 103
 104                 /* Set up inner headers if we are offloading inner checksum */
 105                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 106                         skb_reset_inner_headers(skb);
 107                         skb->encapsulation = 1;
 108                 }
 109
 110                 skb->mac_len = mac_len;
 111                 skb->protocol = protocol;
 112
 113                 __skb_push(skb, outer_hlen);
 114                 skb_reset_mac_header(skb);
 115                 skb_set_network_header(skb, mac_len);
 116                 skb_set_transport_header(skb, udp_offset);
 117                 len = skb->len - udp_offset;
 118                 uh = udp_hdr(skb);
 119
 120                 /* If we are only performing partial GSO the inner header
 121                  * will be using a length value equal to only one MSS sized
 122                  * segment instead of the entire frame.
 123                  */
 124                 if (gso_partial && skb_is_gso(skb)) {
 125                         uh->len = htons(skb_shinfo(skb)->gso_size +
 126                                         SKB_GSO_CB(skb)->data_offset +
 127                                         skb->head - (unsigned char *)uh);
 128                 } else {
 129                         uh->len = htons(len);
 130                 }
 131
 132                 if (!need_csum)
 133                         continue;
 134
 135                 uh->check = ~csum_fold(csum_add(partial,
 136                                        (__force __wsum)htonl(len)));
 137
 138                 if (skb->encapsulation || !offload_csum) {
 139                         uh->check = gso_make_checksum(skb, ~uh->check);
 140                         if (uh->check == 0)
 141                                 uh->check = CSUM_MANGLED_0;
 142                 } else {
 143                         skb->ip_summed = CHECKSUM_PARTIAL;
 144                         skb->csum_start = skb_transport_header(skb) - skb->head;
 145                         skb->csum_offset = offsetof(struct udphdr, check);
 146                 }
 147         } while ((skb = skb->next));
 148 out:
 149         return segs;
 150 }
 151
 152 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 153                                        netdev_features_t features,
 154                                        bool is_ipv6)
 155 {
 156         const struct net_offload __rcu **offloads;
 157         __be16 protocol = skb->protocol;
 158         const struct net_offload *ops;
 159         struct sk_buff *segs = ERR_PTR(-EINVAL);
 160         struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
 161                                              netdev_features_t features);
 162
 163         rcu_read_lock();
 164
 165         switch (skb->inner_protocol_type) {
 166         case ENCAP_TYPE_ETHER:
 167                 protocol = skb->inner_protocol;
 168                 gso_inner_segment = skb_mac_gso_segment;
 169                 break;
 170         case ENCAP_TYPE_IPPROTO:
 171                 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
 172                 ops = rcu_dereference(offloads[skb->inner_ipproto]);
 173                 if (!ops || !ops->callbacks.gso_segment)
 174                         goto out_unlock;
 175                 gso_inner_segment = ops->callbacks.gso_segment;
 176                 break;
 177         default:
 178                 goto out_unlock;
 179         }
 180
 181         segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
 182                                         protocol, is_ipv6);
 183
 184 out_unlock:
 185         rcu_read_unlock();
 186
 187         return segs;
 188 }
 189 EXPORT_SYMBOL(skb_udp_tunnel_segment);
 190
 191 static void __udpv4_gso_segment_csum(struct sk_buff *seg,
 192                                      __be32 *oldip, __be32 *newip,
 193                                      __be16 *oldport, __be16 *newport)
 194 {
 195         struct udphdr *uh;
 196         struct iphdr *iph;
 197
 198         if (*oldip == *newip && *oldport == *newport)
 199                 return;
 200
 201         uh = udp_hdr(seg);
 202         iph = ip_hdr(seg);
 203
 204         if (uh->check) {
 205                 inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
 206                                          true);
 207                 inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
 208                                          false);
 209                 if (!uh->check)
 210                         uh->check = CSUM_MANGLED_0;
 211         }
 212         *oldport = *newport;
 213
 214         csum_replace4(&iph->check, *oldip, *newip);
 215         *oldip = *newip;
 216 }
 217
 218 static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
 219 {
 220         struct sk_buff *seg;
 221         struct udphdr *uh, *uh2;
 222         struct iphdr *iph, *iph2;
 223
 224         seg = segs;
 225         uh = udp_hdr(seg);
 226         iph = ip_hdr(seg);
 227
 228         if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
 229             (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
 230             (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
 231             (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
 232                 return segs;
 233
 234         while ((seg = seg->next)) {
 235                 uh2 = udp_hdr(seg);
 236                 iph2 = ip_hdr(seg);
 237
 238                 __udpv4_gso_segment_csum(seg,
 239                                          &iph2->saddr, &iph->saddr,
 240                                          &uh2->source, &uh->source);
 241                 __udpv4_gso_segment_csum(seg,
 242                                          &iph2->daddr, &iph->daddr,
 243                                          &uh2->dest, &uh->dest);
 244         }
 245
 246         return segs;
 247 }
 248
 249 static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
 250                                               netdev_features_t features,
 251                                               bool is_ipv6)
 252 {
 253         unsigned int mss = skb_shinfo(skb)->gso_size;
 254
 255         skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
 256         if (IS_ERR(skb))
 257                 return skb;
 258
 259         udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
 260
 261         return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
 262 }
 263
 264 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 265                                   netdev_features_t features, bool is_ipv6)
 266 {
 267         struct sock *sk = gso_skb->sk;
 268         unsigned int sum_truesize = 0;
 269         struct sk_buff *segs, *seg;
 270         struct udphdr *uh;
 271         unsigned int mss;
 272         bool copy_dtor;
 273         __sum16 check;
 274         __be16 newlen;
 275
 276         if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
 277                 return __udp_gso_segment_list(gso_skb, features, is_ipv6);
 278
 279         mss = skb_shinfo(gso_skb)->gso_size;
 280         if (gso_skb->len <= sizeof(*uh) + mss)
 281                 return ERR_PTR(-EINVAL);
 282
 283         skb_pull(gso_skb, sizeof(*uh));
 284
 285         /* clear destructor to avoid skb_segment assigning it to tail */
 286         copy_dtor = gso_skb->destructor == sock_wfree;
 287         if (copy_dtor)
 288                 gso_skb->destructor = NULL;
 289
 290         segs = skb_segment(gso_skb, features);
 291         if (IS_ERR_OR_NULL(segs)) {
 292                 if (copy_dtor)
 293                         gso_skb->destructor = sock_wfree;
 294                 return segs;
 295         }
 296
 297         /* GSO partial and frag_list segmentation only requires splitting
 298          * the frame into an MSS multiple and possibly a remainder, both
 299          * cases return a GSO skb. So update the mss now.
 300          */
 301         if (skb_is_gso(segs))
 302                 mss *= skb_shinfo(segs)->gso_segs;
 303
 304         seg = segs;
 305         uh = udp_hdr(seg);
 306
 307         /* preserve TX timestamp flags and TS key for first segment */
 308         skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
 309         skb_shinfo(seg)->tx_flags |=
 310                         (skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
 311
 312         /* compute checksum adjustment based on old length versus new */
 313         newlen = htons(sizeof(*uh) + mss);
 314         check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 315
 316         for (;;) {
 317                 if (copy_dtor) {
 318                         seg->destructor = sock_wfree;
 319                         seg->sk = sk;
 320                         sum_truesize += seg->truesize;
 321                 }
 322
 323                 if (!seg->next)
 324                         break;
 325
 326                 uh->len = newlen;
 327                 uh->check = check;
 328
 329                 if (seg->ip_summed == CHECKSUM_PARTIAL)
 330                         gso_reset_checksum(seg, ~check);
 331                 else
 332                         uh->check = gso_make_checksum(seg, ~check) ? :
 333                                     CSUM_MANGLED_0;
 334
 335                 seg = seg->next;
 336                 uh = udp_hdr(seg);
 337         }
 338
 339         /* last packet can be partial gso_size, account for that in checksum */
 340         newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
 341                        seg->data_len);
 342         check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
 343
 344         uh->len = newlen;
 345         uh->check = check;
 346
 347         if (seg->ip_summed == CHECKSUM_PARTIAL)
 348                 gso_reset_checksum(seg, ~check);
 349         else
 350                 uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
 351
 352         /* update refcount for the packet */
 353         if (copy_dtor) {
 354                 int delta = sum_truesize - gso_skb->truesize;
 355
 356                 /* In some pathological cases, delta can be negative.
 357                  * We need to either use refcount_add() or refcount_sub_and_test()
 358                  */
 359                 if (likely(delta >= 0))
 360                         refcount_add(delta, &sk->sk_wmem_alloc);
 361                 else
 362                         WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
 363         }
 364         return segs;
 365 }
 366 EXPORT_SYMBOL_GPL(__udp_gso_segment);
 367
 368 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 369                                          netdev_features_t features)
 370 {
 371         struct sk_buff *segs = ERR_PTR(-EINVAL);
 372         unsigned int mss;
 373         __wsum csum;
 374         struct udphdr *uh;
 375         struct iphdr *iph;
 376
 377         if (skb->encapsulation &&
 378             (skb_shinfo(skb)->gso_type &
 379              (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
 380                 segs = skb_udp_tunnel_segment(skb, features, false);
 381                 goto out;
 382         }
 383
 384         if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
 385                 goto out;
 386
 387         if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 388                 goto out;
 389
 390         if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
 391                 return __udp_gso_segment(skb, features, false);
 392
 393         mss = skb_shinfo(skb)->gso_size;
 394         if (unlikely(skb->len <= mss))
 395                 goto out;
 396
 397         /* Do software UFO. Complete and fill in the UDP checksum as
 398          * HW cannot do checksum of UDP packets sent as multiple
 399          * IP fragments.
 400          */
 401
 402         uh = udp_hdr(skb);
 403         iph = ip_hdr(skb);
 404
 405         uh->check = 0;
 406         csum = skb_checksum(skb, 0, skb->len, 0);
 407         uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
 408         if (uh->check == 0)
 409                 uh->check = CSUM_MANGLED_0;
 410
 411         skb->ip_summed = CHECKSUM_UNNECESSARY;
 412
 413         /* If there is no outer header we can fake a checksum offload
 414          * due to the fact that we have already done the checksum in
 415          * software prior to segmenting the frame.
 416          */
 417         if (!skb->encap_hdr_csum)
 418                 features |= NETIF_F_HW_CSUM;
 419
 420         /* Fragment the skb. IP headers of the fragments are updated in
 421          * inet_gso_segment()
 422          */
 423         segs = skb_segment(skb, features);
 424 out:
 425         return segs;
 426 }
 427
 428 static int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
 429 {
 430         if (unlikely(p->len + skb->len >= 65536))
 431                 return -E2BIG;
 432
 433         if (NAPI_GRO_CB(p)->last == p)
 434                 skb_shinfo(p)->frag_list = skb;
 435         else
 436                 NAPI_GRO_CB(p)->last->next = skb;
 437
 438         skb_pull(skb, skb_gro_offset(skb));
 439
 440         NAPI_GRO_CB(p)->last = skb;
 441         NAPI_GRO_CB(p)->count++;
 442         p->data_len += skb->len;
 443
 444         /* sk owenrship - if any - completely transferred to the aggregated packet */
 445         skb->destructor = NULL;
 446         p->truesize += skb->truesize;
 447         p->len += skb->len;
 448
 449         NAPI_GRO_CB(skb)->same_flow = 1;
 450
 451         return 0;
 452 }
 453
 454
 455 #define UDP_GRO_CNT_MAX 64
 456 static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
 457                                                struct sk_buff *skb)
 458 {
 459         struct udphdr *uh = udp_gro_udphdr(skb);
 460         struct sk_buff *pp = NULL;
 461         struct udphdr *uh2;
 462         struct sk_buff *p;
 463         unsigned int ulen;
 464         int ret = 0;
 465
 466         /* requires non zero csum, for symmetry with GSO */
 467         if (!uh->check) {
 468                 NAPI_GRO_CB(skb)->flush = 1;
 469                 return NULL;
 470         }
 471
 472         /* Do not deal with padded or malicious packets, sorry ! */
 473         ulen = ntohs(uh->len);
 474         if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
 475                 NAPI_GRO_CB(skb)->flush = 1;
 476                 return NULL;
 477         }
 478         /* pull encapsulating udp header */
 479         skb_gro_pull(skb, sizeof(struct udphdr));
 480
 481         list_for_each_entry(p, head, list) {
 482                 if (!NAPI_GRO_CB(p)->same_flow)
 483                         continue;
 484
 485                 uh2 = udp_hdr(p);
 486
 487                 /* Match ports only, as csum is always non zero */
 488                 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
 489                         NAPI_GRO_CB(p)->same_flow = 0;
 490                         continue;
 491                 }
 492
 493                 if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
 494                         NAPI_GRO_CB(skb)->flush = 1;
 495                         return p;
 496                 }
 497
 498                 /* Terminate the flow on len mismatch or if it grow "too much".
 499                  * Under small packet flood GRO count could elsewhere grow a lot
 500                  * leading to excessive truesize values.
 501                  * On len mismatch merge the first packet shorter than gso_size,
 502                  * otherwise complete the GRO packet.
 503                  */
 504                 if (ulen > ntohs(uh2->len)) {
 505                         pp = p;
 506                 } else {
 507                         if (NAPI_GRO_CB(skb)->is_flist) {
 508                                 if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
 509                                         NAPI_GRO_CB(skb)->flush = 1;
 510                                         return NULL;
 511                                 }
 512                                 if ((skb->ip_summed != p->ip_summed) ||
 513                                     (skb->csum_level != p->csum_level)) {
 514                                         NAPI_GRO_CB(skb)->flush = 1;
 515                                         return NULL;
 516                                 }
 517                                 ret = skb_gro_receive_list(p, skb);
 518                         } else {
 519                                 skb_gro_postpull_rcsum(skb, uh,
 520                                                        sizeof(struct udphdr));
 521
 522                                 ret = skb_gro_receive(p, skb);
 523                         }
 524                 }
 525
 526                 if (ret || ulen != ntohs(uh2->len) ||
 527                     NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
 528                         pp = p;
 529
 530                 return pp;
 531         }
 532
 533         /* mismatch, but we never need to flush */
 534         return NULL;
 535 }
 536
 537 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 538                                 struct udphdr *uh, struct sock *sk)
 539 {
 540         struct sk_buff *pp = NULL;
 541         struct sk_buff *p;
 542         struct udphdr *uh2;
 543         unsigned int off = skb_gro_offset(skb);
 544         int flush = 1;
 545
 546         /* we can do L4 aggregation only if the packet can't land in a tunnel
 547          * otherwise we could corrupt the inner stream
 548          */
 549         NAPI_GRO_CB(skb)->is_flist = 0;
 550         if (!sk || !udp_sk(sk)->gro_receive) {
 551                 if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
 552                         NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled : 1;
 553
 554                 if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
 555                     (sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist)
 556                         return call_gro_receive(udp_gro_receive_segment, head, skb);
 557
 558                 /* no GRO, be sure flush the current packet */
 559                 goto out;
 560         }
 561
 562         if (NAPI_GRO_CB(skb)->encap_mark ||
 563             (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
 564              NAPI_GRO_CB(skb)->csum_cnt == 0 &&
 565              !NAPI_GRO_CB(skb)->csum_valid))
 566                 goto out;
 567
 568         /* mark that this skb passed once through the tunnel gro layer */
 569         NAPI_GRO_CB(skb)->encap_mark = 1;
 570
 571         flush = 0;
 572
 573         list_for_each_entry(p, head, list) {
 574                 if (!NAPI_GRO_CB(p)->same_flow)
 575                         continue;
 576
 577                 uh2 = (struct udphdr   *)(p->data + off);
 578
 579                 /* Match ports and either checksums are either both zero
 580                  * or nonzero.
 581                  */
 582                 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
 583                     (!uh->check ^ !uh2->check)) {
 584                         NAPI_GRO_CB(p)->same_flow = 0;
 585                         continue;
 586                 }
 587         }
 588
 589         skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
 590         skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
 591         pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
 592
 593 out:
 594         skb_gro_flush_final(skb, pp, flush);
 595         return pp;
 596 }
 597 EXPORT_SYMBOL(udp_gro_receive);
 598
 599 static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
 600                                         __be16 dport)
 601 {
 602         const struct iphdr *iph = skb_gro_network_header(skb);
 603
 604         return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
 605                                  iph->daddr, dport, inet_iif(skb),
 606                                  inet_sdif(skb), &udp_table, NULL);
 607 }
 608
 609 INDIRECT_CALLABLE_SCOPE
 610 struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
 611 {
 612         struct udphdr *uh = udp_gro_udphdr(skb);
 613         struct sock *sk = NULL;
 614         struct sk_buff *pp;
 615
 616         if (unlikely(!uh))
 617                 goto flush;
 618
 619         /* Don't bother verifying checksum if we're going to flush anyway. */
 620         if (NAPI_GRO_CB(skb)->flush)
 621                 goto skip;
 622
 623         if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
 624                                                  inet_gro_compute_pseudo))
 625                 goto flush;
 626         else if (uh->check)
 627                 skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
 628                                              inet_gro_compute_pseudo);
 629 skip:
 630         NAPI_GRO_CB(skb)->is_ipv6 = 0;
 631
 632         if (static_branch_unlikely(&udp_encap_needed_key))
 633                 sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
 634
 635         pp = udp_gro_receive(head, skb, uh, sk);
 636         return pp;
 637
 638 flush:
 639         NAPI_GRO_CB(skb)->flush = 1;
 640         return NULL;
 641 }
 642
 643 static int udp_gro_complete_segment(struct sk_buff *skb)
 644 {
 645         struct udphdr *uh = udp_hdr(skb);
 646
 647         skb->csum_start = (unsigned char *)uh - skb->head;
 648         skb->csum_offset = offsetof(struct udphdr, check);
 649         skb->ip_summed = CHECKSUM_PARTIAL;
 650
 651         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 652         skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
 653
 654         if (skb->encapsulation)
 655                 skb->inner_transport_header = skb->transport_header;
 656
 657         return 0;
 658 }
 659
 660 int udp_gro_complete(struct sk_buff *skb, int nhoff,
 661                      udp_lookup_t lookup)
 662 {
 663         __be16 newlen = htons(skb->len - nhoff);
 664         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 665         struct sock *sk;
 666         int err;
 667
 668         uh->len = newlen;
 669
 670         sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
 671                                 udp4_lib_lookup_skb, skb, uh->source, uh->dest);
 672         if (sk && udp_sk(sk)->gro_complete) {
 673                 skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
 674                                         : SKB_GSO_UDP_TUNNEL;
 675
 676                 /* clear the encap mark, so that inner frag_list gro_complete
 677                  * can take place
 678                  */
 679                 NAPI_GRO_CB(skb)->encap_mark = 0;
 680
 681                 /* Set encapsulation before calling into inner gro_complete()
 682                  * functions to make them set up the inner offsets.
 683                  */
 684                 skb->encapsulation = 1;
 685                 err = udp_sk(sk)->gro_complete(sk, skb,
 686                                 nhoff + sizeof(struct udphdr));
 687         } else {
 688                 err = udp_gro_complete_segment(skb);
 689         }
 690
 691         if (skb->remcsum_offload)
 692                 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
 693
 694         return err;
 695 }
 696 EXPORT_SYMBOL(udp_gro_complete);
 697
 698 INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
 699 {
 700         const struct iphdr *iph = ip_hdr(skb);
 701         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 702
 703         /* do fraglist only if there is no outer UDP encap (or we already processed it) */
 704         if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
 705                 uh->len = htons(skb->len - nhoff);
 706
 707                 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
 708                 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 709
 710                 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 711                         if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
 712                                 skb->csum_level++;
 713                 } else {
 714                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 715                         skb->csum_level = 0;
 716                 }
 717
 718                 return 0;
 719         }
 720
 721         if (uh->check)
 722                 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
 723                                           iph->daddr, 0);
 724
 725         return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
 726 }
 727
 728 static const struct net_offload udpv4_offload = {
 729         .callbacks = {
 730                 .gso_segment = udp4_ufo_fragment,
 731                 .gro_receive  = udp4_gro_receive,
 732                 .gro_complete = udp4_gro_complete,
 733         },
 734 };
 735
 736 int __init udpv4_offload_init(void)
 737 {
 738         return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
 739 }