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   1 /*
   2  *  linux/net/ipv4/inet_lro.c
   3  *
   4  *  Large Receive Offload (ipv4 / tcp)
   5  *
   6  *  (C) Copyright IBM Corp. 2007
   7  *
   8  *  Authors:
   9  *       Jan-Bernd Themann <themann@de.ibm.com>
  10  *       Christoph Raisch <raisch@de.ibm.com>
  11  *
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2, or (at your option)
  16  * any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26  */
  27
  28
  29 #include <linux/module.h>
  30 #include <linux/if_vlan.h>
  31 #include <linux/inet_lro.h>
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("Jan-Bernd Themann <themann@de.ibm.com>");
  35 MODULE_DESCRIPTION("Large Receive Offload (ipv4 / tcp)");
  36
  37 #define TCP_HDR_LEN(tcph) (tcph->doff << 2)
  38 #define IP_HDR_LEN(iph) (iph->ihl << 2)
  39 #define TCP_PAYLOAD_LENGTH(iph, tcph) \
  40         (ntohs(iph->tot_len) - IP_HDR_LEN(iph) - TCP_HDR_LEN(tcph))
  41
  42 #define IPH_LEN_WO_OPTIONS 5
  43 #define TCPH_LEN_WO_OPTIONS 5
  44 #define TCPH_LEN_W_TIMESTAMP 8
  45
  46 #define LRO_MAX_PG_HLEN 64
  47
  48 #define LRO_INC_STATS(lro_mgr, attr) { lro_mgr->stats.attr++; }
  49
  50 /*
  51  * Basic tcp checks whether packet is suitable for LRO
  52  */
  53
  54 static int lro_tcp_ip_check(struct iphdr *iph, struct tcphdr *tcph,
  55                             int len, struct net_lro_desc *lro_desc)
  56 {
  57         /* check ip header: don't aggregate padded frames */
  58         if (ntohs(iph->tot_len) != len)
  59                 return -1;
  60
  61         if (TCP_PAYLOAD_LENGTH(iph, tcph) == 0)
  62                 return -1;
  63
  64         if (iph->ihl != IPH_LEN_WO_OPTIONS)
  65                 return -1;
  66
  67         if (tcph->cwr || tcph->ece || tcph->urg || !tcph->ack
  68             || tcph->rst || tcph->syn || tcph->fin)
  69                 return -1;
  70
  71         if (INET_ECN_is_ce(ipv4_get_dsfield(iph)))
  72                 return -1;
  73
  74         if (tcph->doff != TCPH_LEN_WO_OPTIONS
  75             && tcph->doff != TCPH_LEN_W_TIMESTAMP)
  76                 return -1;
  77
  78         /* check tcp options (only timestamp allowed) */
  79         if (tcph->doff == TCPH_LEN_W_TIMESTAMP) {
  80                 __be32 *topt = (__be32 *)(tcph + 1);
  81
  82                 if (*topt != htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
  83                                    | (TCPOPT_TIMESTAMP << 8)
  84                                    | TCPOLEN_TIMESTAMP))
  85                         return -1;
  86
  87                 /* timestamp should be in right order */
  88                 topt++;
  89                 if (lro_desc && after(ntohl(lro_desc->tcp_rcv_tsval),
  90                                       ntohl(*topt)))
  91                         return -1;
  92
  93                 /* timestamp reply should not be zero */
  94                 topt++;
  95                 if (*topt == 0)
  96                         return -1;
  97         }
  98
  99         return 0;
 100 }
 101
 102 static void lro_update_tcp_ip_header(struct net_lro_desc *lro_desc)
 103 {
 104         struct iphdr *iph = lro_desc->iph;
 105         struct tcphdr *tcph = lro_desc->tcph;
 106         __be32 *p;
 107         __wsum tcp_hdr_csum;
 108
 109         tcph->ack_seq = lro_desc->tcp_ack;
 110         tcph->window = lro_desc->tcp_window;
 111
 112         if (lro_desc->tcp_saw_tstamp) {
 113                 p = (__be32 *)(tcph + 1);
 114                 *(p+2) = lro_desc->tcp_rcv_tsecr;
 115         }
 116
 117         iph->tot_len = htons(lro_desc->ip_tot_len);
 118
 119         iph->check = 0;
 120         iph->check = ip_fast_csum((u8 *)lro_desc->iph, iph->ihl);
 121
 122         tcph->check = 0;
 123         tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), 0);
 124         lro_desc->data_csum = csum_add(lro_desc->data_csum, tcp_hdr_csum);
 125         tcph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
 126                                         lro_desc->ip_tot_len -
 127                                         IP_HDR_LEN(iph), IPPROTO_TCP,
 128                                         lro_desc->data_csum);
 129 }
 130
 131 static __wsum lro_tcp_data_csum(struct iphdr *iph, struct tcphdr *tcph, int len)
 132 {
 133         __wsum tcp_csum;
 134         __wsum tcp_hdr_csum;
 135         __wsum tcp_ps_hdr_csum;
 136
 137         tcp_csum = ~csum_unfold(tcph->check);
 138         tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), tcp_csum);
 139
 140         tcp_ps_hdr_csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
 141                                              len + TCP_HDR_LEN(tcph),
 142                                              IPPROTO_TCP, 0);
 143
 144         return csum_sub(csum_sub(tcp_csum, tcp_hdr_csum),
 145                         tcp_ps_hdr_csum);
 146 }
 147
 148 static void lro_init_desc(struct net_lro_desc *lro_desc, struct sk_buff *skb,
 149                           struct iphdr *iph, struct tcphdr *tcph,
 150                           u16 vlan_tag, struct vlan_group *vgrp)
 151 {
 152         int nr_frags;
 153         __be32 *ptr;
 154         u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
 155
 156         nr_frags = skb_shinfo(skb)->nr_frags;
 157         lro_desc->parent = skb;
 158         lro_desc->next_frag = &(skb_shinfo(skb)->frags[nr_frags]);
 159         lro_desc->iph = iph;
 160         lro_desc->tcph = tcph;
 161         lro_desc->tcp_next_seq = ntohl(tcph->seq) + tcp_data_len;
 162         lro_desc->tcp_ack = tcph->ack_seq;
 163         lro_desc->tcp_window = tcph->window;
 164
 165         lro_desc->pkt_aggr_cnt = 1;
 166         lro_desc->ip_tot_len = ntohs(iph->tot_len);
 167
 168         if (tcph->doff == 8) {
 169                 ptr = (__be32 *)(tcph+1);
 170                 lro_desc->tcp_saw_tstamp = 1;
 171                 lro_desc->tcp_rcv_tsval = *(ptr+1);
 172                 lro_desc->tcp_rcv_tsecr = *(ptr+2);
 173         }
 174
 175         lro_desc->mss = tcp_data_len;
 176         lro_desc->vgrp = vgrp;
 177         lro_desc->vlan_tag = vlan_tag;
 178         lro_desc->active = 1;
 179
 180         lro_desc->data_csum = lro_tcp_data_csum(iph, tcph,
 181                                                 tcp_data_len);
 182 }
 183
 184 static inline void lro_clear_desc(struct net_lro_desc *lro_desc)
 185 {
 186         memset(lro_desc, 0, sizeof(struct net_lro_desc));
 187 }
 188
 189 static void lro_add_common(struct net_lro_desc *lro_desc, struct iphdr *iph,
 190                            struct tcphdr *tcph, int tcp_data_len)
 191 {
 192         struct sk_buff *parent = lro_desc->parent;
 193         __be32 *topt;
 194
 195         lro_desc->pkt_aggr_cnt++;
 196         lro_desc->ip_tot_len += tcp_data_len;
 197         lro_desc->tcp_next_seq += tcp_data_len;
 198         lro_desc->tcp_window = tcph->window;
 199         lro_desc->tcp_ack = tcph->ack_seq;
 200
 201         /* don't update tcp_rcv_tsval, would not work with PAWS */
 202         if (lro_desc->tcp_saw_tstamp) {
 203                 topt = (__be32 *) (tcph + 1);
 204                 lro_desc->tcp_rcv_tsecr = *(topt + 2);
 205         }
 206
 207         lro_desc->data_csum = csum_block_add(lro_desc->data_csum,
 208                                              lro_tcp_data_csum(iph, tcph,
 209                                                                tcp_data_len),
 210                                              parent->len);
 211
 212         parent->len += tcp_data_len;
 213         parent->data_len += tcp_data_len;
 214         if (tcp_data_len > lro_desc->mss)
 215                 lro_desc->mss = tcp_data_len;
 216 }
 217
 218 static void lro_add_packet(struct net_lro_desc *lro_desc, struct sk_buff *skb,
 219                            struct iphdr *iph, struct tcphdr *tcph)
 220 {
 221         struct sk_buff *parent = lro_desc->parent;
 222         int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
 223
 224         lro_add_common(lro_desc, iph, tcph, tcp_data_len);
 225
 226         skb_pull(skb, (skb->len - tcp_data_len));
 227         parent->truesize += skb->truesize;
 228
 229         if (lro_desc->last_skb)
 230                 lro_desc->last_skb->next = skb;
 231         else
 232                 skb_shinfo(parent)->frag_list = skb;
 233
 234         lro_desc->last_skb = skb;
 235 }
 236
 237 static void lro_add_frags(struct net_lro_desc *lro_desc,
 238                           int len, int hlen, int truesize,
 239                           struct skb_frag_struct *skb_frags,
 240                           struct iphdr *iph, struct tcphdr *tcph)
 241 {
 242         struct sk_buff *skb = lro_desc->parent;
 243         int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
 244
 245         lro_add_common(lro_desc, iph, tcph, tcp_data_len);
 246
 247         skb->truesize += truesize;
 248
 249         skb_frags[0].page_offset += hlen;
 250         skb_frags[0].size -= hlen;
 251
 252         while (tcp_data_len > 0) {
 253                 *(lro_desc->next_frag) = *skb_frags;
 254                 tcp_data_len -= skb_frags->size;
 255                 lro_desc->next_frag++;
 256                 skb_frags++;
 257                 skb_shinfo(skb)->nr_frags++;
 258         }
 259 }
 260
 261 static int lro_check_tcp_conn(struct net_lro_desc *lro_desc,
 262                               struct iphdr *iph,
 263                               struct tcphdr *tcph)
 264 {
 265         if ((lro_desc->iph->saddr != iph->saddr)
 266             || (lro_desc->iph->daddr != iph->daddr)
 267             || (lro_desc->tcph->source != tcph->source)
 268             || (lro_desc->tcph->dest != tcph->dest))
 269                 return -1;
 270         return 0;
 271 }
 272
 273 static struct net_lro_desc *lro_get_desc(struct net_lro_mgr *lro_mgr,
 274                                          struct net_lro_desc *lro_arr,
 275                                          struct iphdr *iph,
 276                                          struct tcphdr *tcph)
 277 {
 278         struct net_lro_desc *lro_desc = NULL;
 279         struct net_lro_desc *tmp;
 280         int max_desc = lro_mgr->max_desc;
 281         int i;
 282
 283         for (i = 0; i < max_desc; i++) {
 284                 tmp = &lro_arr[i];
 285                 if (tmp->active)
 286                         if (!lro_check_tcp_conn(tmp, iph, tcph)) {
 287                                 lro_desc = tmp;
 288                                 goto out;
 289                         }
 290         }
 291
 292         for (i = 0; i < max_desc; i++) {
 293                 if (!lro_arr[i].active) {
 294                         lro_desc = &lro_arr[i];
 295                         goto out;
 296                 }
 297         }
 298
 299         LRO_INC_STATS(lro_mgr, no_desc);
 300 out:
 301         return lro_desc;
 302 }
 303
 304 static void lro_flush(struct net_lro_mgr *lro_mgr,
 305                       struct net_lro_desc *lro_desc)
 306 {
 307         if (lro_desc->pkt_aggr_cnt > 1)
 308                 lro_update_tcp_ip_header(lro_desc);
 309
 310         skb_shinfo(lro_desc->parent)->gso_size = lro_desc->mss;
 311
 312         if (lro_desc->vgrp) {
 313                 if (lro_mgr->features & LRO_F_NAPI)
 314                         vlan_hwaccel_receive_skb(lro_desc->parent,
 315                                                  lro_desc->vgrp,
 316                                                  lro_desc->vlan_tag);
 317                 else
 318                         vlan_hwaccel_rx(lro_desc->parent,
 319                                         lro_desc->vgrp,
 320                                         lro_desc->vlan_tag);
 321
 322         } else {
 323                 if (lro_mgr->features & LRO_F_NAPI)
 324                         netif_receive_skb(lro_desc->parent);
 325                 else
 326                         netif_rx(lro_desc->parent);
 327         }
 328
 329         LRO_INC_STATS(lro_mgr, flushed);
 330         lro_clear_desc(lro_desc);
 331 }
 332
 333 static int __lro_proc_skb(struct net_lro_mgr *lro_mgr, struct sk_buff *skb,
 334                           struct vlan_group *vgrp, u16 vlan_tag, void *priv)
 335 {
 336         struct net_lro_desc *lro_desc;
 337         struct iphdr *iph;
 338         struct tcphdr *tcph;
 339         u64 flags;
 340         int vlan_hdr_len = 0;
 341
 342         if (!lro_mgr->get_skb_header
 343             || lro_mgr->get_skb_header(skb, (void *)&iph, (void *)&tcph,
 344                                        &flags, priv))
 345                 goto out;
 346
 347         if (!(flags & LRO_IPV4) || !(flags & LRO_TCP))
 348                 goto out;
 349
 350         lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
 351         if (!lro_desc)
 352                 goto out;
 353
 354         if ((skb->protocol == htons(ETH_P_8021Q))
 355             && !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
 356                 vlan_hdr_len = VLAN_HLEN;
 357
 358         if (!lro_desc->active) { /* start new lro session */
 359                 if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, NULL))
 360                         goto out;
 361
 362                 skb->ip_summed = lro_mgr->ip_summed_aggr;
 363                 lro_init_desc(lro_desc, skb, iph, tcph, vlan_tag, vgrp);
 364                 LRO_INC_STATS(lro_mgr, aggregated);
 365                 return 0;
 366         }
 367
 368         if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
 369                 goto out2;
 370
 371         if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
 372                 goto out2;
 373
 374         lro_add_packet(lro_desc, skb, iph, tcph);
 375         LRO_INC_STATS(lro_mgr, aggregated);
 376
 377         if ((lro_desc->pkt_aggr_cnt >= lro_mgr->max_aggr) ||
 378             lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
 379                 lro_flush(lro_mgr, lro_desc);
 380
 381         return 0;
 382
 383 out2: /* send aggregated SKBs to stack */
 384         lro_flush(lro_mgr, lro_desc);
 385
 386 out:
 387         return 1;
 388 }
 389
 390
 391 static struct sk_buff *lro_gen_skb(struct net_lro_mgr *lro_mgr,
 392                                    struct skb_frag_struct *frags,
 393                                    int len, int true_size,
 394                                    void *mac_hdr,
 395                                    int hlen, __wsum sum,
 396                                    u32 ip_summed)
 397 {
 398         struct sk_buff *skb;
 399         struct skb_frag_struct *skb_frags;
 400         int data_len = len;
 401         int hdr_len = min(len, hlen);
 402
 403         skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
 404         if (!skb)
 405                 return NULL;
 406
 407         skb_reserve(skb, lro_mgr->frag_align_pad);
 408         skb->len = len;
 409         skb->data_len = len - hdr_len;
 410         skb->truesize += true_size;
 411         skb->tail += hdr_len;
 412
 413         memcpy(skb->data, mac_hdr, hdr_len);
 414
 415         skb_frags = skb_shinfo(skb)->frags;
 416         while (data_len > 0) {
 417                 *skb_frags = *frags;
 418                 data_len -= frags->size;
 419                 skb_frags++;
 420                 frags++;
 421                 skb_shinfo(skb)->nr_frags++;
 422         }
 423
 424         skb_shinfo(skb)->frags[0].page_offset += hdr_len;
 425         skb_shinfo(skb)->frags[0].size -= hdr_len;
 426
 427         skb->ip_summed = ip_summed;
 428         skb->csum = sum;
 429         skb->protocol = eth_type_trans(skb, lro_mgr->dev);
 430         return skb;
 431 }
 432
 433 static struct sk_buff *__lro_proc_segment(struct net_lro_mgr *lro_mgr,
 434                                           struct skb_frag_struct *frags,
 435                                           int len, int true_size,
 436                                           struct vlan_group *vgrp,
 437                                           u16 vlan_tag, void *priv, __wsum sum)
 438 {
 439         struct net_lro_desc *lro_desc;
 440         struct iphdr *iph;
 441         struct tcphdr *tcph;
 442         struct sk_buff *skb;
 443         u64 flags;
 444         void *mac_hdr;
 445         int mac_hdr_len;
 446         int hdr_len = LRO_MAX_PG_HLEN;
 447         int vlan_hdr_len = 0;
 448
 449         if (!lro_mgr->get_frag_header
 450             || lro_mgr->get_frag_header(frags, (void *)&mac_hdr, (void *)&iph,
 451                                         (void *)&tcph, &flags, priv)) {
 452                 mac_hdr = page_address(frags->page) + frags->page_offset;
 453                 goto out1;
 454         }
 455
 456         if (!(flags & LRO_IPV4) || !(flags & LRO_TCP))
 457                 goto out1;
 458
 459         hdr_len = (int)((void *)(tcph) + TCP_HDR_LEN(tcph) - mac_hdr);
 460         mac_hdr_len = (int)((void *)(iph) - mac_hdr);
 461
 462         lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
 463         if (!lro_desc)
 464                 goto out1;
 465
 466         if (!lro_desc->active) { /* start new lro session */
 467                 if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, NULL))
 468                         goto out1;
 469
 470                 skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
 471                                   hdr_len, 0, lro_mgr->ip_summed_aggr);
 472                 if (!skb)
 473                         goto out;
 474
 475                 if ((skb->protocol == htons(ETH_P_8021Q))
 476                     && !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
 477                         vlan_hdr_len = VLAN_HLEN;
 478
 479                 iph = (void *)(skb->data + vlan_hdr_len);
 480                 tcph = (void *)((u8 *)skb->data + vlan_hdr_len
 481                                 + IP_HDR_LEN(iph));
 482
 483                 lro_init_desc(lro_desc, skb, iph, tcph, 0, NULL);
 484                 LRO_INC_STATS(lro_mgr, aggregated);
 485                 return NULL;
 486         }
 487
 488         if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
 489                 goto out2;
 490
 491         if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, lro_desc))
 492                 goto out2;
 493
 494         lro_add_frags(lro_desc, len, hdr_len, true_size, frags, iph, tcph);
 495         LRO_INC_STATS(lro_mgr, aggregated);
 496
 497         if ((skb_shinfo(lro_desc->parent)->nr_frags >= lro_mgr->max_aggr) ||
 498             lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
 499                 lro_flush(lro_mgr, lro_desc);
 500
 501         return NULL;
 502
 503 out2: /* send aggregated packets to the stack */
 504         lro_flush(lro_mgr, lro_desc);
 505
 506 out1:  /* Original packet has to be posted to the stack */
 507         skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
 508                           hdr_len, sum, lro_mgr->ip_summed);
 509 out:
 510         return skb;
 511 }
 512
 513 void lro_receive_skb(struct net_lro_mgr *lro_mgr,
 514                      struct sk_buff *skb,
 515                      void *priv)
 516 {
 517         if (__lro_proc_skb(lro_mgr, skb, NULL, 0, priv)) {
 518                 if (lro_mgr->features & LRO_F_NAPI)
 519                         netif_receive_skb(skb);
 520                 else
 521                         netif_rx(skb);
 522         }
 523 }
 524 EXPORT_SYMBOL(lro_receive_skb);
 525
 526 void lro_vlan_hwaccel_receive_skb(struct net_lro_mgr *lro_mgr,
 527                                   struct sk_buff *skb,
 528                                   struct vlan_group *vgrp,
 529                                   u16 vlan_tag,
 530                                   void *priv)
 531 {
 532         if (__lro_proc_skb(lro_mgr, skb, vgrp, vlan_tag, priv)) {
 533                 if (lro_mgr->features & LRO_F_NAPI)
 534                         vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
 535                 else
 536                         vlan_hwaccel_rx(skb, vgrp, vlan_tag);
 537         }
 538 }
 539 EXPORT_SYMBOL(lro_vlan_hwaccel_receive_skb);
 540
 541 void lro_receive_frags(struct net_lro_mgr *lro_mgr,
 542                        struct skb_frag_struct *frags,
 543                        int len, int true_size, void *priv, __wsum sum)
 544 {
 545         struct sk_buff *skb;
 546
 547         skb = __lro_proc_segment(lro_mgr, frags, len, true_size, NULL, 0,
 548                                  priv, sum);
 549         if (!skb)
 550                 return;
 551
 552         if (lro_mgr->features & LRO_F_NAPI)
 553                 netif_receive_skb(skb);
 554         else
 555                 netif_rx(skb);
 556 }
 557 EXPORT_SYMBOL(lro_receive_frags);
 558
 559 void lro_vlan_hwaccel_receive_frags(struct net_lro_mgr *lro_mgr,
 560                                     struct skb_frag_struct *frags,
 561                                     int len, int true_size,
 562                                     struct vlan_group *vgrp,
 563                                     u16 vlan_tag, void *priv, __wsum sum)
 564 {
 565         struct sk_buff *skb;
 566
 567         skb = __lro_proc_segment(lro_mgr, frags, len, true_size, vgrp,
 568                                  vlan_tag, priv, sum);
 569         if (!skb)
 570                 return;
 571
 572         if (lro_mgr->features & LRO_F_NAPI)
 573                 vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
 574         else
 575                 vlan_hwaccel_rx(skb, vgrp, vlan_tag);
 576 }
 577 EXPORT_SYMBOL(lro_vlan_hwaccel_receive_frags);
 578
 579 void lro_flush_all(struct net_lro_mgr *lro_mgr)
 580 {
 581         int i;
 582         struct net_lro_desc *lro_desc = lro_mgr->lro_arr;
 583
 584         for (i = 0; i < lro_mgr->max_desc; i++) {
 585                 if (lro_desc[i].active)
 586                         lro_flush(lro_mgr, &lro_desc[i]);
 587         }
 588 }
 589 EXPORT_SYMBOL(lro_flush_all);
 590
 591 void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
 592                   struct iphdr *iph, struct tcphdr *tcph)
 593 {
 594         struct net_lro_desc *lro_desc;
 595
 596         lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
 597         if (lro_desc->active)
 598                 lro_flush(lro_mgr, lro_desc);
 599 }
 600 EXPORT_SYMBOL(lro_flush_pkt);