tcp_lro.c

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    1 /*-
    2  * Copyright (c) 2007, Myricom Inc.
    3  * Copyright (c) 2008, Intel Corporation.
    4  * Copyright (c) 2012 The FreeBSD Foundation
    5  * Copyright (c) 2016 Mellanox Technologies.
    6  * All rights reserved.
    7  *
    8  * Portions of this software were developed by Bjoern Zeeb
    9  * under sponsorship from the FreeBSD Foundation.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __FBSDID("$FreeBSD$");
   35 
   36 #include "opt_inet.h"
   37 #include "opt_inet6.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/kernel.h>
   42 #include <sys/malloc.h>
   43 #include <sys/mbuf.h>
   44 #include <sys/socket.h>
   45 #include <sys/sysctl.h>
   46 
   47 #include <net/if.h>
   48 #include <net/if_var.h>
   49 #include <net/ethernet.h>
   50 #include <net/vnet.h>
   51 
   52 #include <netinet/in_systm.h>
   53 #include <netinet/in.h>
   54 #include <netinet/ip6.h>
   55 #include <netinet/ip.h>
   56 #include <netinet/ip_var.h>
   57 #include <netinet/tcp.h>
   58 #include <netinet/tcp_seq.h>
   59 #include <netinet/tcp_lro.h>
   60 #include <netinet/tcp_var.h>
   61 
   62 #include <netinet6/ip6_var.h>
   63 
   64 #include <machine/in_cksum.h>
   65 
   66 static MALLOC_DEFINE(M_LRO, "LRO", "LRO control structures");
   67 
   68 #define TCP_LRO_UPDATE_CSUM     1
   69 #ifndef TCP_LRO_UPDATE_CSUM
   70 #define TCP_LRO_INVALID_CSUM    0x0000
   71 #endif
   72 
   73 static void     tcp_lro_rx_done(struct lro_ctrl *lc);
   74 
   75 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, lro,  CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
   76     "TCP LRO");
   77 
   78 static unsigned tcp_lro_entries = TCP_LRO_ENTRIES;
   79 SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, entries,
   80     CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_entries, 0,
   81     "default number of LRO entries");
   82 
   83 static __inline void
   84 tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_entry *le)
   85 {
   86 
   87         LIST_INSERT_HEAD(&lc->lro_active, le, next);
   88 }
   89 
   90 static __inline void
   91 tcp_lro_active_remove(struct lro_entry *le)
   92 {
   93 
   94         LIST_REMOVE(le, next);
   95 }
   96 
   97 int
   98 tcp_lro_init(struct lro_ctrl *lc)
   99 {
  100         return (tcp_lro_init_args(lc, NULL, tcp_lro_entries, 0));
  101 }
  102 
  103 int
  104 tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
  105     unsigned lro_entries, unsigned lro_mbufs)
  106 {
  107         struct lro_entry *le;
  108         size_t size;
  109         unsigned i;
  110 
  111         lc->lro_bad_csum = 0;
  112         lc->lro_queued = 0;
  113         lc->lro_flushed = 0;
  114         lc->lro_mbuf_count = 0;
  115         lc->lro_mbuf_max = lro_mbufs;
  116         lc->lro_cnt = lro_entries;
  117         lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
  118         lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
  119         lc->ifp = ifp;
  120         LIST_INIT(&lc->lro_free);
  121         LIST_INIT(&lc->lro_active);
  122 
  123         /* compute size to allocate */
  124         size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) +
  125             (lro_entries * sizeof(*le));
  126         lc->lro_mbuf_data = (struct lro_mbuf_sort *)
  127             malloc(size, M_LRO, M_NOWAIT | M_ZERO);
  128 
  129         /* check for out of memory */
  130         if (lc->lro_mbuf_data == NULL) {
  131                 memset(lc, 0, sizeof(*lc));
  132                 return (ENOMEM);
  133         }
  134         /* compute offset for LRO entries */
  135         le = (struct lro_entry *)
  136             (lc->lro_mbuf_data + lro_mbufs);
  137 
  138         /* setup linked list */
  139         for (i = 0; i != lro_entries; i++)
  140                 LIST_INSERT_HEAD(&lc->lro_free, le + i, next);
  141 
  142         return (0);
  143 }
  144 
  145 void
  146 tcp_lro_free(struct lro_ctrl *lc)
  147 {
  148         struct lro_entry *le;
  149         unsigned x;
  150 
  151         /* reset LRO free list */
  152         LIST_INIT(&lc->lro_free);
  153 
  154         /* free active mbufs, if any */
  155         while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
  156                 tcp_lro_active_remove(le);
  157                 m_freem(le->m_head);
  158         }
  159 
  160         /* free mbuf array, if any */
  161         for (x = 0; x != lc->lro_mbuf_count; x++)
  162                 m_freem(lc->lro_mbuf_data[x].mb);
  163         lc->lro_mbuf_count = 0;
  164         
  165         /* free allocated memory, if any */
  166         free(lc->lro_mbuf_data, M_LRO);
  167         lc->lro_mbuf_data = NULL;
  168 }
  169 
  170 #ifdef TCP_LRO_UPDATE_CSUM
  171 static uint16_t
  172 tcp_lro_csum_th(struct tcphdr *th)
  173 {
  174         uint32_t ch;
  175         uint16_t *p, l;
  176 
  177         ch = th->th_sum = 0x0000;
  178         l = th->th_off;
  179         p = (uint16_t *)th;
  180         while (l > 0) {
  181                 ch += *p;
  182                 p++;
  183                 ch += *p;
  184                 p++;
  185                 l--;
  186         }
  187         while (ch > 0xffff)
  188                 ch = (ch >> 16) + (ch & 0xffff);
  189 
  190         return (ch & 0xffff);
  191 }
  192 
  193 static uint16_t
  194 tcp_lro_rx_csum_fixup(struct lro_entry *le, void *l3hdr, struct tcphdr *th,
  195     uint16_t tcp_data_len, uint16_t csum)
  196 {
  197         uint32_t c;
  198         uint16_t cs;
  199 
  200         c = csum;
  201 
  202         /* Remove length from checksum. */
  203         switch (le->eh_type) {
  204 #ifdef INET6
  205         case ETHERTYPE_IPV6:
  206         {
  207                 struct ip6_hdr *ip6;
  208 
  209                 ip6 = (struct ip6_hdr *)l3hdr;
  210                 if (le->append_cnt == 0)
  211                         cs = ip6->ip6_plen;
  212                 else {
  213                         uint32_t cx;
  214 
  215                         cx = ntohs(ip6->ip6_plen);
  216                         cs = in6_cksum_pseudo(ip6, cx, ip6->ip6_nxt, 0);
  217                 }
  218                 break;
  219         }
  220 #endif
  221 #ifdef INET
  222         case ETHERTYPE_IP:
  223         {
  224                 struct ip *ip4;
  225 
  226                 ip4 = (struct ip *)l3hdr;
  227                 if (le->append_cnt == 0)
  228                         cs = ip4->ip_len;
  229                 else {
  230                         cs = in_addword(ntohs(ip4->ip_len) - sizeof(*ip4),
  231                             IPPROTO_TCP);
  232                         cs = in_pseudo(ip4->ip_src.s_addr, ip4->ip_dst.s_addr,
  233                             htons(cs));
  234                 }
  235                 break;
  236         }
  237 #endif
  238         default:
  239                 cs = 0;         /* Keep compiler happy. */
  240         }
  241 
  242         cs = ~cs;
  243         c += cs;
  244 
  245         /* Remove TCP header csum. */
  246         cs = ~tcp_lro_csum_th(th);
  247         c += cs;
  248         while (c > 0xffff)
  249                 c = (c >> 16) + (c & 0xffff);
  250 
  251         return (c & 0xffff);
  252 }
  253 #endif
  254 
  255 static void
  256 tcp_lro_rx_done(struct lro_ctrl *lc)
  257 {
  258         struct lro_entry *le;
  259 
  260         while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
  261                 tcp_lro_active_remove(le);
  262                 tcp_lro_flush(lc, le);
  263         }
  264 }
  265 
  266 void
  267 tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
  268 {
  269         struct lro_entry *le, *le_tmp;
  270         struct timeval tv;
  271 
  272         if (LIST_EMPTY(&lc->lro_active))
  273                 return;
  274 
  275         getmicrotime(&tv);
  276         timevalsub(&tv, timeout);
  277         LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
  278                 if (timevalcmp(&tv, &le->mtime, >=)) {
  279                         tcp_lro_active_remove(le);
  280                         tcp_lro_flush(lc, le);
  281                 }
  282         }
  283 }
  284 
  285 void
  286 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
  287 {
  288 
  289         if (le->append_cnt > 0) {
  290                 struct tcphdr *th;
  291                 uint16_t p_len;
  292 
  293                 p_len = htons(le->p_len);
  294                 switch (le->eh_type) {
  295 #ifdef INET6
  296                 case ETHERTYPE_IPV6:
  297                 {
  298                         struct ip6_hdr *ip6;
  299 
  300                         ip6 = le->le_ip6;
  301                         ip6->ip6_plen = p_len;
  302                         th = (struct tcphdr *)(ip6 + 1);
  303                         le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
  304                             CSUM_PSEUDO_HDR;
  305                         le->p_len += ETHER_HDR_LEN + sizeof(*ip6);
  306                         break;
  307                 }
  308 #endif
  309 #ifdef INET
  310                 case ETHERTYPE_IP:
  311                 {
  312                         struct ip *ip4;
  313 #ifdef TCP_LRO_UPDATE_CSUM
  314                         uint32_t cl;
  315                         uint16_t c;
  316 #endif
  317 
  318                         ip4 = le->le_ip4;
  319 #ifdef TCP_LRO_UPDATE_CSUM
  320                         /* Fix IP header checksum for new length. */
  321                         c = ~ip4->ip_sum;
  322                         cl = c;
  323                         c = ~ip4->ip_len;
  324                         cl += c + p_len;
  325                         while (cl > 0xffff)
  326                                 cl = (cl >> 16) + (cl & 0xffff);
  327                         c = cl;
  328                         ip4->ip_sum = ~c;
  329 #else
  330                         ip4->ip_sum = TCP_LRO_INVALID_CSUM;
  331 #endif
  332                         ip4->ip_len = p_len;
  333                         th = (struct tcphdr *)(ip4 + 1);
  334                         le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
  335                             CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
  336                         le->p_len += ETHER_HDR_LEN;
  337                         break;
  338                 }
  339 #endif
  340                 default:
  341                         th = NULL;      /* Keep compiler happy. */
  342                 }
  343                 le->m_head->m_pkthdr.csum_data = 0xffff;
  344                 le->m_head->m_pkthdr.len = le->p_len;
  345 
  346                 /* Incorporate the latest ACK into the TCP header. */
  347                 th->th_ack = le->ack_seq;
  348                 th->th_win = le->window;
  349                 /* Incorporate latest timestamp into the TCP header. */
  350                 if (le->timestamp != 0) {
  351                         uint32_t *ts_ptr;
  352 
  353                         ts_ptr = (uint32_t *)(th + 1);
  354                         ts_ptr[1] = htonl(le->tsval);
  355                         ts_ptr[2] = le->tsecr;
  356                 }
  357 #ifdef TCP_LRO_UPDATE_CSUM
  358                 /* Update the TCP header checksum. */
  359                 le->ulp_csum += p_len;
  360                 le->ulp_csum += tcp_lro_csum_th(th);
  361                 while (le->ulp_csum > 0xffff)
  362                         le->ulp_csum = (le->ulp_csum >> 16) +
  363                             (le->ulp_csum & 0xffff);
  364                 th->th_sum = (le->ulp_csum & 0xffff);
  365                 th->th_sum = ~th->th_sum;
  366 #else
  367                 th->th_sum = TCP_LRO_INVALID_CSUM;
  368 #endif
  369         }
  370 
  371         (*lc->ifp->if_input)(lc->ifp, le->m_head);
  372         lc->lro_queued += le->append_cnt + 1;
  373         lc->lro_flushed++;
  374         bzero(le, sizeof(*le));
  375         LIST_INSERT_HEAD(&lc->lro_free, le, next);
  376 }
  377 
  378 #ifdef HAVE_INLINE_FLSLL
  379 #define tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
  380 #else
  381 static inline uint64_t
  382 tcp_lro_msb_64(uint64_t x)
  383 {
  384         x |= (x >> 1);
  385         x |= (x >> 2);
  386         x |= (x >> 4);
  387         x |= (x >> 8);
  388         x |= (x >> 16);
  389         x |= (x >> 32);
  390         return (x & ~(x >> 1));
  391 }
  392 #endif
  393 
  394 /*
  395  * The tcp_lro_sort() routine is comparable to qsort(), except it has
  396  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
  397  * number of elements to sort and 64 is the number of sequence bits
  398  * available. The algorithm is bit-slicing the 64-bit sequence number,
  399  * sorting one bit at a time from the most significant bit until the
  400  * least significant one, skipping the constant bits. This is
  401  * typically called a radix sort.
  402  */
  403 static void
  404 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
  405 {
  406         struct lro_mbuf_sort temp;
  407         uint64_t ones;
  408         uint64_t zeros;
  409         uint32_t x;
  410         uint32_t y;
  411 
  412 repeat:
  413         /* for small arrays insertion sort is faster */
  414         if (size <= 12) {
  415                 for (x = 1; x < size; x++) {
  416                         temp = parray[x];
  417                         for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
  418                                 parray[y] = parray[y - 1];
  419                         parray[y] = temp;
  420                 }
  421                 return;
  422         }
  423 
  424         /* compute sequence bits which are constant */
  425         ones = 0;
  426         zeros = 0;
  427         for (x = 0; x != size; x++) {
  428                 ones |= parray[x].seq;
  429                 zeros |= ~parray[x].seq;
  430         }
  431 
  432         /* compute bits which are not constant into "ones" */
  433         ones &= zeros;
  434         if (ones == 0)
  435                 return;
  436 
  437         /* pick the most significant bit which is not constant */
  438         ones = tcp_lro_msb_64(ones);
  439 
  440         /*
  441          * Move entries having cleared sequence bits to the beginning
  442          * of the array:
  443          */
  444         for (x = y = 0; y != size; y++) {
  445                 /* skip set bits */
  446                 if (parray[y].seq & ones)
  447                         continue;
  448                 /* swap entries */
  449                 temp = parray[x];
  450                 parray[x] = parray[y];
  451                 parray[y] = temp;
  452                 x++;
  453         }
  454 
  455         KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
  456 
  457         /* sort zeros */
  458         tcp_lro_sort(parray, x);
  459 
  460         /* sort ones */
  461         parray += x;
  462         size -= x;
  463         goto repeat;
  464 }
  465 
  466 void
  467 tcp_lro_flush_all(struct lro_ctrl *lc)
  468 {
  469         uint64_t seq;
  470         uint64_t nseq;
  471         unsigned x;
  472 
  473         /* check if no mbufs to flush */
  474         if (lc->lro_mbuf_count == 0)
  475                 goto done;
  476 
  477         /* sort all mbufs according to stream */
  478         tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
  479 
  480         /* input data into LRO engine, stream by stream */
  481         seq = 0;
  482         for (x = 0; x != lc->lro_mbuf_count; x++) {
  483                 struct mbuf *mb;
  484 
  485                 /* get mbuf */
  486                 mb = lc->lro_mbuf_data[x].mb;
  487 
  488                 /* get sequence number, masking away the packet index */
  489                 nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
  490 
  491                 /* check for new stream */
  492                 if (seq != nseq) {
  493                         seq = nseq;
  494 
  495                         /* flush active streams */
  496                         tcp_lro_rx_done(lc);
  497                 }
  498 
  499                 /* add packet to LRO engine */
  500                 if (tcp_lro_rx(lc, mb, 0) != 0) {
  501                         /* input packet to network layer */
  502                         (*lc->ifp->if_input)(lc->ifp, mb);
  503                         lc->lro_queued++;
  504                         lc->lro_flushed++;
  505                 }
  506         }
  507 done:
  508         /* flush active streams */
  509         tcp_lro_rx_done(lc);
  510 
  511         lc->lro_mbuf_count = 0;
  512 }
  513 
  514 #ifdef INET6
  515 static int
  516 tcp_lro_rx_ipv6(struct lro_ctrl *lc, struct mbuf *m, struct ip6_hdr *ip6,
  517     struct tcphdr **th)
  518 {
  519 
  520         /* XXX-BZ we should check the flow-label. */
  521 
  522         /* XXX-BZ We do not yet support ext. hdrs. */
  523         if (ip6->ip6_nxt != IPPROTO_TCP)
  524                 return (TCP_LRO_NOT_SUPPORTED);
  525 
  526         /* Find the TCP header. */
  527         *th = (struct tcphdr *)(ip6 + 1);
  528 
  529         return (0);
  530 }
  531 #endif
  532 
  533 #ifdef INET
  534 static int
  535 tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4,
  536     struct tcphdr **th)
  537 {
  538         int csum_flags;
  539         uint16_t csum;
  540 
  541         if (ip4->ip_p != IPPROTO_TCP)
  542                 return (TCP_LRO_NOT_SUPPORTED);
  543 
  544         /* Ensure there are no options. */
  545         if ((ip4->ip_hl << 2) != sizeof (*ip4))
  546                 return (TCP_LRO_CANNOT);
  547 
  548         /* .. and the packet is not fragmented. */
  549         if (ip4->ip_off & htons(IP_MF|IP_OFFMASK))
  550                 return (TCP_LRO_CANNOT);
  551 
  552         /* Legacy IP has a header checksum that needs to be correct. */
  553         csum_flags = m->m_pkthdr.csum_flags;
  554         if (csum_flags & CSUM_IP_CHECKED) {
  555                 if (__predict_false((csum_flags & CSUM_IP_VALID) == 0)) {
  556                         lc->lro_bad_csum++;
  557                         return (TCP_LRO_CANNOT);
  558                 }
  559         } else {
  560                 csum = in_cksum_hdr(ip4);
  561                 if (__predict_false((csum) != 0)) {
  562                         lc->lro_bad_csum++;
  563                         return (TCP_LRO_CANNOT);
  564                 }
  565         }
  566 
  567         /* Find the TCP header (we assured there are no IP options). */
  568         *th = (struct tcphdr *)(ip4 + 1);
  569 
  570         return (0);
  571 }
  572 #endif
  573 
  574 int
  575 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
  576 {
  577         struct lro_entry *le;
  578         struct ether_header *eh;
  579 #ifdef INET6
  580         struct ip6_hdr *ip6 = NULL;     /* Keep compiler happy. */
  581 #endif
  582 #ifdef INET
  583         struct ip *ip4 = NULL;          /* Keep compiler happy. */
  584 #endif
  585         struct tcphdr *th;
  586         void *l3hdr = NULL;             /* Keep compiler happy. */
  587         uint32_t *ts_ptr;
  588         tcp_seq seq;
  589         int error, ip_len, l;
  590         uint16_t eh_type, tcp_data_len;
  591         int force_flush = 0;
  592 
  593         /* We expect a contiguous header [eh, ip, tcp]. */
  594 
  595         eh = mtod(m, struct ether_header *);
  596         eh_type = ntohs(eh->ether_type);
  597         switch (eh_type) {
  598 #ifdef INET6
  599         case ETHERTYPE_IPV6:
  600         {
  601                 CURVNET_SET(lc->ifp->if_vnet);
  602                 if (V_ip6_forwarding != 0) {
  603                         /* XXX-BZ stats but changing lro_ctrl is a problem. */
  604                         CURVNET_RESTORE();
  605                         return (TCP_LRO_CANNOT);
  606                 }
  607                 CURVNET_RESTORE();
  608                 l3hdr = ip6 = (struct ip6_hdr *)(eh + 1);
  609                 error = tcp_lro_rx_ipv6(lc, m, ip6, &th);
  610                 if (error != 0)
  611                         return (error);
  612                 tcp_data_len = ntohs(ip6->ip6_plen);
  613                 ip_len = sizeof(*ip6) + tcp_data_len;
  614                 break;
  615         }
  616 #endif
  617 #ifdef INET
  618         case ETHERTYPE_IP:
  619         {
  620                 CURVNET_SET(lc->ifp->if_vnet);
  621                 if (V_ipforwarding != 0) {
  622                         /* XXX-BZ stats but changing lro_ctrl is a problem. */
  623                         CURVNET_RESTORE();
  624                         return (TCP_LRO_CANNOT);
  625                 }
  626                 CURVNET_RESTORE();
  627                 l3hdr = ip4 = (struct ip *)(eh + 1);
  628                 error = tcp_lro_rx_ipv4(lc, m, ip4, &th);
  629                 if (error != 0)
  630                         return (error);
  631                 ip_len = ntohs(ip4->ip_len);
  632                 tcp_data_len = ip_len - sizeof(*ip4);
  633                 break;
  634         }
  635 #endif
  636         /* XXX-BZ what happens in case of VLAN(s)? */
  637         default:
  638                 return (TCP_LRO_NOT_SUPPORTED);
  639         }
  640 
  641         /*
  642          * If the frame is padded beyond the end of the IP packet, then we must
  643          * trim the extra bytes off.
  644          */
  645         l = m->m_pkthdr.len - (ETHER_HDR_LEN + ip_len);
  646         if (l != 0) {
  647                 if (l < 0)
  648                         /* Truncated packet. */
  649                         return (TCP_LRO_CANNOT);
  650 
  651                 m_adj(m, -l);
  652         }
  653 
  654         /*
  655          * Check TCP header constraints.
  656          */
  657         /* Ensure no bits set besides ACK or PSH. */
  658         if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0) {
  659                 if (th->th_flags & TH_SYN)
  660                         return (TCP_LRO_CANNOT);
  661                 /*
  662                  * Make sure that previously seen segements/ACKs are delivered
  663                  * before this segement, e.g. FIN.
  664                  */
  665                 force_flush = 1;
  666         }
  667 
  668         /* XXX-BZ We lose a ACK|PUSH flag concatenating multiple segments. */
  669         /* XXX-BZ Ideally we'd flush on PUSH? */
  670 
  671         /*
  672          * Check for timestamps.
  673          * Since the only option we handle are timestamps, we only have to
  674          * handle the simple case of aligned timestamps.
  675          */
  676         l = (th->th_off << 2);
  677         tcp_data_len -= l;
  678         l -= sizeof(*th);
  679         ts_ptr = (uint32_t *)(th + 1);
  680         if (l != 0 && (__predict_false(l != TCPOLEN_TSTAMP_APPA) ||
  681             (*ts_ptr != ntohl(TCPOPT_NOP<<24|TCPOPT_NOP<<16|
  682             TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)))) {
  683                 /*
  684                  * Make sure that previously seen segements/ACKs are delivered
  685                  * before this segement.
  686                  */
  687                 force_flush = 1;
  688         }
  689 
  690         /* If the driver did not pass in the checksum, set it now. */
  691         if (csum == 0x0000)
  692                 csum = th->th_sum;
  693 
  694         seq = ntohl(th->th_seq);
  695 
  696         /* Try to find a matching previous segment. */
  697         LIST_FOREACH(le, &lc->lro_active, next) {
  698                 if (le->eh_type != eh_type)
  699                         continue;
  700                 if (le->source_port != th->th_sport ||
  701                     le->dest_port != th->th_dport)
  702                         continue;
  703                 switch (eh_type) {
  704 #ifdef INET6
  705                 case ETHERTYPE_IPV6:
  706                         if (bcmp(&le->source_ip6, &ip6->ip6_src,
  707                             sizeof(struct in6_addr)) != 0 ||
  708                             bcmp(&le->dest_ip6, &ip6->ip6_dst,
  709                             sizeof(struct in6_addr)) != 0)
  710                                 continue;
  711                         break;
  712 #endif
  713 #ifdef INET
  714                 case ETHERTYPE_IP:
  715                         if (le->source_ip4 != ip4->ip_src.s_addr ||
  716                             le->dest_ip4 != ip4->ip_dst.s_addr)
  717                                 continue;
  718                         break;
  719 #endif
  720                 }
  721 
  722                 if (force_flush) {
  723                         /* Timestamps mismatch; this is a FIN, etc */
  724                         tcp_lro_active_remove(le);
  725                         tcp_lro_flush(lc, le);
  726                         return (TCP_LRO_CANNOT);
  727                 }
  728 
  729                 /* Flush now if appending will result in overflow. */
  730                 if (le->p_len > (lc->lro_length_lim - tcp_data_len)) {
  731                         tcp_lro_active_remove(le);
  732                         tcp_lro_flush(lc, le);
  733                         break;
  734                 }
  735 
  736                 /* Try to append the new segment. */
  737                 if (__predict_false(seq != le->next_seq ||
  738                     (tcp_data_len == 0 &&
  739                     le->ack_seq == th->th_ack &&
  740                     le->window == th->th_win))) {
  741                         /* Out of order packet or duplicate ACK. */
  742                         tcp_lro_active_remove(le);
  743                         tcp_lro_flush(lc, le);
  744                         return (TCP_LRO_CANNOT);
  745                 }
  746 
  747                 if (l != 0) {
  748                         uint32_t tsval = ntohl(*(ts_ptr + 1));
  749                         /* Make sure timestamp values are increasing. */
  750                         /* XXX-BZ flip and use TSTMP_GEQ macro for this? */
  751                         if (__predict_false(le->tsval > tsval ||
  752                             *(ts_ptr + 2) == 0))
  753                                 return (TCP_LRO_CANNOT);
  754                         le->tsval = tsval;
  755                         le->tsecr = *(ts_ptr + 2);
  756                 }
  757                 if (tcp_data_len || SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) {
  758                         le->next_seq += tcp_data_len;
  759                         le->ack_seq = th->th_ack;
  760                         le->window = th->th_win;
  761                         le->append_cnt++;
  762                 } else if (th->th_ack == le->ack_seq) {
  763                         le->window = WIN_MAX(le->window, th->th_win);
  764                         le->append_cnt++;
  765                 } else {
  766                         /* no data and old ack */
  767                         le->append_cnt++;
  768                         m_freem(m);
  769                         return (0);
  770                 }
  771 #ifdef TCP_LRO_UPDATE_CSUM
  772                 le->ulp_csum += tcp_lro_rx_csum_fixup(le, l3hdr, th,
  773                     tcp_data_len, ~csum);
  774 #endif
  775 
  776                 if (tcp_data_len == 0) {
  777                         m_freem(m);
  778                         /*
  779                          * Flush this LRO entry, if this ACK should not
  780                          * be further delayed.
  781                          */
  782                         if (le->append_cnt >= lc->lro_ackcnt_lim) {
  783                                 tcp_lro_active_remove(le);
  784                                 tcp_lro_flush(lc, le);
  785                         }
  786                         return (0);
  787                 }
  788 
  789                 le->p_len += tcp_data_len;
  790 
  791                 /*
  792                  * Adjust the mbuf so that m_data points to the first byte of
  793                  * the ULP payload.  Adjust the mbuf to avoid complications and
  794                  * append new segment to existing mbuf chain.
  795                  */
  796                 m_adj(m, m->m_pkthdr.len - tcp_data_len);
  797                 m_demote_pkthdr(m);
  798 
  799                 le->m_tail->m_next = m;
  800                 le->m_tail = m_last(m);
  801 
  802                 /*
  803                  * If a possible next full length packet would cause an
  804                  * overflow, pro-actively flush now.
  805                  */
  806                 if (le->p_len > (lc->lro_length_lim - lc->ifp->if_mtu)) {
  807                         tcp_lro_active_remove(le);
  808                         tcp_lro_flush(lc, le);
  809                 } else
  810                         getmicrotime(&le->mtime);
  811 
  812                 return (0);
  813         }
  814 
  815         if (force_flush) {
  816                 /*
  817                  * Nothing to flush, but this segment can not be further
  818                  * aggregated/delayed.
  819                  */
  820                 return (TCP_LRO_CANNOT);
  821         }
  822 
  823         /* Try to find an empty slot. */
  824         if (LIST_EMPTY(&lc->lro_free))
  825                 return (TCP_LRO_NO_ENTRIES);
  826 
  827         /* Start a new segment chain. */
  828         le = LIST_FIRST(&lc->lro_free);
  829         LIST_REMOVE(le, next);
  830         tcp_lro_active_insert(lc, le);
  831         getmicrotime(&le->mtime);
  832 
  833         /* Start filling in details. */
  834         switch (eh_type) {
  835 #ifdef INET6
  836         case ETHERTYPE_IPV6:
  837                 le->le_ip6 = ip6;
  838                 le->source_ip6 = ip6->ip6_src;
  839                 le->dest_ip6 = ip6->ip6_dst;
  840                 le->eh_type = eh_type;
  841                 le->p_len = m->m_pkthdr.len - ETHER_HDR_LEN - sizeof(*ip6);
  842                 break;
  843 #endif
  844 #ifdef INET
  845         case ETHERTYPE_IP:
  846                 le->le_ip4 = ip4;
  847                 le->source_ip4 = ip4->ip_src.s_addr;
  848                 le->dest_ip4 = ip4->ip_dst.s_addr;
  849                 le->eh_type = eh_type;
  850                 le->p_len = m->m_pkthdr.len - ETHER_HDR_LEN;
  851                 break;
  852 #endif
  853         }
  854         le->source_port = th->th_sport;
  855         le->dest_port = th->th_dport;
  856 
  857         le->next_seq = seq + tcp_data_len;
  858         le->ack_seq = th->th_ack;
  859         le->window = th->th_win;
  860         if (l != 0) {
  861                 le->timestamp = 1;
  862                 le->tsval = ntohl(*(ts_ptr + 1));
  863                 le->tsecr = *(ts_ptr + 2);
  864         }
  865 
  866 #ifdef TCP_LRO_UPDATE_CSUM
  867         /*
  868          * Do not touch the csum of the first packet.  However save the
  869          * "adjusted" checksum of just the source and destination addresses,
  870          * the next header and the TCP payload.  The length and TCP header
  871          * parts may change, so we remove those from the saved checksum and
  872          * re-add with final values on tcp_lro_flush() if needed.
  873          */
  874         KASSERT(le->ulp_csum == 0, ("%s: le=%p le->ulp_csum=0x%04x\n",
  875             __func__, le, le->ulp_csum));
  876 
  877         le->ulp_csum = tcp_lro_rx_csum_fixup(le, l3hdr, th, tcp_data_len,
  878             ~csum);
  879         th->th_sum = csum;      /* Restore checksum on first packet. */
  880 #endif
  881 
  882         le->m_head = m;
  883         le->m_tail = m_last(m);
  884 
  885         return (0);
  886 }
  887 
  888 void
  889 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
  890 {
  891         /* sanity checks */
  892         if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
  893             lc->lro_mbuf_max == 0)) {
  894                 /* packet drop */
  895                 m_freem(mb);
  896                 return;
  897         }
  898 
  899         /* check if packet is not LRO capable */
  900         if (__predict_false(mb->m_pkthdr.csum_flags == 0 ||
  901             (lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
  902 
  903                 /* input packet to network layer */
  904                 (*lc->ifp->if_input) (lc->ifp, mb);
  905                 return;
  906         }
  907 
  908         /* create sequence number */
  909         lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
  910             (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
  911             (((uint64_t)mb->m_pkthdr.flowid) << 24) |
  912             ((uint64_t)lc->lro_mbuf_count);
  913 
  914         /* enter mbuf */
  915         lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb;
  916 
  917         /* flush if array is full */
  918         if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max))
  919                 tcp_lro_flush_all(lc);
  920 }
  921 
  922 /* end */
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FreeBSD/Linux Kernel Cross Reference sys/netinet/tcp_lro.c

FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_lro.c
