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: releng/11.0/sys/netinet/tcp_lro.c 301249 2016-06-03 08:35:07Z hselasky $");
   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 
   46 #include <net/if.h>
   47 #include <net/if_var.h>
   48 #include <net/ethernet.h>
   49 #include <net/vnet.h>
   50 
   51 #include <netinet/in_systm.h>
   52 #include <netinet/in.h>
   53 #include <netinet/ip6.h>
   54 #include <netinet/ip.h>
   55 #include <netinet/ip_var.h>
   56 #include <netinet/tcp.h>
   57 #include <netinet/tcp_lro.h>
   58 
   59 #include <netinet6/ip6_var.h>
   60 
   61 #include <machine/in_cksum.h>
   62 
   63 static MALLOC_DEFINE(M_LRO, "LRO", "LRO control structures");
   64 
   65 #define TCP_LRO_UPDATE_CSUM     1
   66 #ifndef TCP_LRO_UPDATE_CSUM
   67 #define TCP_LRO_INVALID_CSUM    0x0000
   68 #endif
   69 
   70 static void     tcp_lro_rx_done(struct lro_ctrl *lc);
   71 
   72 static __inline void
   73 tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_entry *le)
   74 {
   75 
   76         LIST_INSERT_HEAD(&lc->lro_active, le, next);
   77 }
   78 
   79 static __inline void
   80 tcp_lro_active_remove(struct lro_entry *le)
   81 {
   82 
   83         LIST_REMOVE(le, next);
   84 }
   85 
   86 int
   87 tcp_lro_init(struct lro_ctrl *lc)
   88 {
   89         return (tcp_lro_init_args(lc, NULL, TCP_LRO_ENTRIES, 0));
   90 }
   91 
   92 int
   93 tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp,
   94     unsigned lro_entries, unsigned lro_mbufs)
   95 {
   96         struct lro_entry *le;
   97         size_t size;
   98         unsigned i;
   99 
  100         lc->lro_bad_csum = 0;
  101         lc->lro_queued = 0;
  102         lc->lro_flushed = 0;
  103         lc->lro_cnt = 0;
  104         lc->lro_mbuf_count = 0;
  105         lc->lro_mbuf_max = lro_mbufs;
  106         lc->lro_cnt = lro_entries;
  107         lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX;
  108         lc->lro_length_lim = TCP_LRO_LENGTH_MAX;
  109         lc->ifp = ifp;
  110         LIST_INIT(&lc->lro_free);
  111         LIST_INIT(&lc->lro_active);
  112 
  113         /* compute size to allocate */
  114         size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) +
  115             (lro_entries * sizeof(*le));
  116         lc->lro_mbuf_data = (struct lro_mbuf_sort *)
  117             malloc(size, M_LRO, M_NOWAIT | M_ZERO);
  118 
  119         /* check for out of memory */
  120         if (lc->lro_mbuf_data == NULL) {
  121                 memset(lc, 0, sizeof(*lc));
  122                 return (ENOMEM);
  123         }
  124         /* compute offset for LRO entries */
  125         le = (struct lro_entry *)
  126             (lc->lro_mbuf_data + lro_mbufs);
  127 
  128         /* setup linked list */
  129         for (i = 0; i != lro_entries; i++)
  130                 LIST_INSERT_HEAD(&lc->lro_free, le + i, next);
  131 
  132         return (0);
  133 }
  134 
  135 void
  136 tcp_lro_free(struct lro_ctrl *lc)
  137 {
  138         struct lro_entry *le;
  139         unsigned x;
  140 
  141         /* reset LRO free list */
  142         LIST_INIT(&lc->lro_free);
  143 
  144         /* free active mbufs, if any */
  145         while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
  146                 tcp_lro_active_remove(le);
  147                 m_freem(le->m_head);
  148         }
  149 
  150         /* free mbuf array, if any */
  151         for (x = 0; x != lc->lro_mbuf_count; x++)
  152                 m_freem(lc->lro_mbuf_data[x].mb);
  153         lc->lro_mbuf_count = 0;
  154         
  155         /* free allocated memory, if any */
  156         free(lc->lro_mbuf_data, M_LRO);
  157         lc->lro_mbuf_data = NULL;
  158 }
  159 
  160 #ifdef TCP_LRO_UPDATE_CSUM
  161 static uint16_t
  162 tcp_lro_csum_th(struct tcphdr *th)
  163 {
  164         uint32_t ch;
  165         uint16_t *p, l;
  166 
  167         ch = th->th_sum = 0x0000;
  168         l = th->th_off;
  169         p = (uint16_t *)th;
  170         while (l > 0) {
  171                 ch += *p;
  172                 p++;
  173                 ch += *p;
  174                 p++;
  175                 l--;
  176         }
  177         while (ch > 0xffff)
  178                 ch = (ch >> 16) + (ch & 0xffff);
  179 
  180         return (ch & 0xffff);
  181 }
  182 
  183 static uint16_t
  184 tcp_lro_rx_csum_fixup(struct lro_entry *le, void *l3hdr, struct tcphdr *th,
  185     uint16_t tcp_data_len, uint16_t csum)
  186 {
  187         uint32_t c;
  188         uint16_t cs;
  189 
  190         c = csum;
  191 
  192         /* Remove length from checksum. */
  193         switch (le->eh_type) {
  194 #ifdef INET6
  195         case ETHERTYPE_IPV6:
  196         {
  197                 struct ip6_hdr *ip6;
  198 
  199                 ip6 = (struct ip6_hdr *)l3hdr;
  200                 if (le->append_cnt == 0)
  201                         cs = ip6->ip6_plen;
  202                 else {
  203                         uint32_t cx;
  204 
  205                         cx = ntohs(ip6->ip6_plen);
  206                         cs = in6_cksum_pseudo(ip6, cx, ip6->ip6_nxt, 0);
  207                 }
  208                 break;
  209         }
  210 #endif
  211 #ifdef INET
  212         case ETHERTYPE_IP:
  213         {
  214                 struct ip *ip4;
  215 
  216                 ip4 = (struct ip *)l3hdr;
  217                 if (le->append_cnt == 0)
  218                         cs = ip4->ip_len;
  219                 else {
  220                         cs = in_addword(ntohs(ip4->ip_len) - sizeof(*ip4),
  221                             IPPROTO_TCP);
  222                         cs = in_pseudo(ip4->ip_src.s_addr, ip4->ip_dst.s_addr,
  223                             htons(cs));
  224                 }
  225                 break;
  226         }
  227 #endif
  228         default:
  229                 cs = 0;         /* Keep compiler happy. */
  230         }
  231 
  232         cs = ~cs;
  233         c += cs;
  234 
  235         /* Remove TCP header csum. */
  236         cs = ~tcp_lro_csum_th(th);
  237         c += cs;
  238         while (c > 0xffff)
  239                 c = (c >> 16) + (c & 0xffff);
  240 
  241         return (c & 0xffff);
  242 }
  243 #endif
  244 
  245 static void
  246 tcp_lro_rx_done(struct lro_ctrl *lc)
  247 {
  248         struct lro_entry *le;
  249 
  250         while ((le = LIST_FIRST(&lc->lro_active)) != NULL) {
  251                 tcp_lro_active_remove(le);
  252                 tcp_lro_flush(lc, le);
  253         }
  254 }
  255 
  256 void
  257 tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
  258 {
  259         struct lro_entry *le, *le_tmp;
  260         struct timeval tv;
  261 
  262         if (LIST_EMPTY(&lc->lro_active))
  263                 return;
  264 
  265         getmicrotime(&tv);
  266         timevalsub(&tv, timeout);
  267         LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
  268                 if (timevalcmp(&tv, &le->mtime, >=)) {
  269                         tcp_lro_active_remove(le);
  270                         tcp_lro_flush(lc, le);
  271                 }
  272         }
  273 }
  274 
  275 void
  276 tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le)
  277 {
  278 
  279         if (le->append_cnt > 0) {
  280                 struct tcphdr *th;
  281                 uint16_t p_len;
  282 
  283                 p_len = htons(le->p_len);
  284                 switch (le->eh_type) {
  285 #ifdef INET6
  286                 case ETHERTYPE_IPV6:
  287                 {
  288                         struct ip6_hdr *ip6;
  289 
  290                         ip6 = le->le_ip6;
  291                         ip6->ip6_plen = p_len;
  292                         th = (struct tcphdr *)(ip6 + 1);
  293                         le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
  294                             CSUM_PSEUDO_HDR;
  295                         le->p_len += ETHER_HDR_LEN + sizeof(*ip6);
  296                         break;
  297                 }
  298 #endif
  299 #ifdef INET
  300                 case ETHERTYPE_IP:
  301                 {
  302                         struct ip *ip4;
  303 #ifdef TCP_LRO_UPDATE_CSUM
  304                         uint32_t cl;
  305                         uint16_t c;
  306 #endif
  307 
  308                         ip4 = le->le_ip4;
  309 #ifdef TCP_LRO_UPDATE_CSUM
  310                         /* Fix IP header checksum for new length. */
  311                         c = ~ip4->ip_sum;
  312                         cl = c;
  313                         c = ~ip4->ip_len;
  314                         cl += c + p_len;
  315                         while (cl > 0xffff)
  316                                 cl = (cl >> 16) + (cl & 0xffff);
  317                         c = cl;
  318                         ip4->ip_sum = ~c;
  319 #else
  320                         ip4->ip_sum = TCP_LRO_INVALID_CSUM;
  321 #endif
  322                         ip4->ip_len = p_len;
  323                         th = (struct tcphdr *)(ip4 + 1);
  324                         le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID |
  325                             CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID;
  326                         le->p_len += ETHER_HDR_LEN;
  327                         break;
  328                 }
  329 #endif
  330                 default:
  331                         th = NULL;      /* Keep compiler happy. */
  332                 }
  333                 le->m_head->m_pkthdr.csum_data = 0xffff;
  334                 le->m_head->m_pkthdr.len = le->p_len;
  335 
  336                 /* Incorporate the latest ACK into the TCP header. */
  337                 th->th_ack = le->ack_seq;
  338                 th->th_win = le->window;
  339                 /* Incorporate latest timestamp into the TCP header. */
  340                 if (le->timestamp != 0) {
  341                         uint32_t *ts_ptr;
  342 
  343                         ts_ptr = (uint32_t *)(th + 1);
  344                         ts_ptr[1] = htonl(le->tsval);
  345                         ts_ptr[2] = le->tsecr;
  346                 }
  347 #ifdef TCP_LRO_UPDATE_CSUM
  348                 /* Update the TCP header checksum. */
  349                 le->ulp_csum += p_len;
  350                 le->ulp_csum += tcp_lro_csum_th(th);
  351                 while (le->ulp_csum > 0xffff)
  352                         le->ulp_csum = (le->ulp_csum >> 16) +
  353                             (le->ulp_csum & 0xffff);
  354                 th->th_sum = (le->ulp_csum & 0xffff);
  355                 th->th_sum = ~th->th_sum;
  356 #else
  357                 th->th_sum = TCP_LRO_INVALID_CSUM;
  358 #endif
  359         }
  360 
  361         (*lc->ifp->if_input)(lc->ifp, le->m_head);
  362         lc->lro_queued += le->append_cnt + 1;
  363         lc->lro_flushed++;
  364         bzero(le, sizeof(*le));
  365         LIST_INSERT_HEAD(&lc->lro_free, le, next);
  366 }
  367 
  368 #ifdef HAVE_INLINE_FLSLL
  369 #define tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1))
  370 #else
  371 static inline uint64_t
  372 tcp_lro_msb_64(uint64_t x)
  373 {
  374         x |= (x >> 1);
  375         x |= (x >> 2);
  376         x |= (x >> 4);
  377         x |= (x >> 8);
  378         x |= (x >> 16);
  379         x |= (x >> 32);
  380         return (x & ~(x >> 1));
  381 }
  382 #endif
  383 
  384 /*
  385  * The tcp_lro_sort() routine is comparable to qsort(), except it has
  386  * a worst case complexity limit of O(MIN(N,64)*N), where N is the
  387  * number of elements to sort and 64 is the number of sequence bits
  388  * available. The algorithm is bit-slicing the 64-bit sequence number,
  389  * sorting one bit at a time from the most significant bit until the
  390  * least significant one, skipping the constant bits. This is
  391  * typically called a radix sort.
  392  */
  393 static void
  394 tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size)
  395 {
  396         struct lro_mbuf_sort temp;
  397         uint64_t ones;
  398         uint64_t zeros;
  399         uint32_t x;
  400         uint32_t y;
  401 
  402 repeat:
  403         /* for small arrays insertion sort is faster */
  404         if (size <= 12) {
  405                 for (x = 1; x < size; x++) {
  406                         temp = parray[x];
  407                         for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--)
  408                                 parray[y] = parray[y - 1];
  409                         parray[y] = temp;
  410                 }
  411                 return;
  412         }
  413 
  414         /* compute sequence bits which are constant */
  415         ones = 0;
  416         zeros = 0;
  417         for (x = 0; x != size; x++) {
  418                 ones |= parray[x].seq;
  419                 zeros |= ~parray[x].seq;
  420         }
  421 
  422         /* compute bits which are not constant into "ones" */
  423         ones &= zeros;
  424         if (ones == 0)
  425                 return;
  426 
  427         /* pick the most significant bit which is not constant */
  428         ones = tcp_lro_msb_64(ones);
  429 
  430         /*
  431          * Move entries having cleared sequence bits to the beginning
  432          * of the array:
  433          */
  434         for (x = y = 0; y != size; y++) {
  435                 /* skip set bits */
  436                 if (parray[y].seq & ones)
  437                         continue;
  438                 /* swap entries */
  439                 temp = parray[x];
  440                 parray[x] = parray[y];
  441                 parray[y] = temp;
  442                 x++;
  443         }
  444 
  445         KASSERT(x != 0 && x != size, ("Memory is corrupted\n"));
  446 
  447         /* sort zeros */
  448         tcp_lro_sort(parray, x);
  449 
  450         /* sort ones */
  451         parray += x;
  452         size -= x;
  453         goto repeat;
  454 }
  455 
  456 void
  457 tcp_lro_flush_all(struct lro_ctrl *lc)
  458 {
  459         uint64_t seq;
  460         uint64_t nseq;
  461         unsigned x;
  462 
  463         /* check if no mbufs to flush */
  464         if (lc->lro_mbuf_count == 0)
  465                 goto done;
  466 
  467         /* sort all mbufs according to stream */
  468         tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
  469 
  470         /* input data into LRO engine, stream by stream */
  471         seq = 0;
  472         for (x = 0; x != lc->lro_mbuf_count; x++) {
  473                 struct mbuf *mb;
  474 
  475                 /* get mbuf */
  476                 mb = lc->lro_mbuf_data[x].mb;
  477 
  478                 /* get sequence number, masking away the packet index */
  479                 nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24);
  480 
  481                 /* check for new stream */
  482                 if (seq != nseq) {
  483                         seq = nseq;
  484 
  485                         /* flush active streams */
  486                         tcp_lro_rx_done(lc);
  487                 }
  488 
  489                 /* add packet to LRO engine */
  490                 if (tcp_lro_rx(lc, mb, 0) != 0) {
  491                         /* input packet to network layer */
  492                         (*lc->ifp->if_input)(lc->ifp, mb);
  493                         lc->lro_queued++;
  494                         lc->lro_flushed++;
  495                 }
  496         }
  497 done:
  498         /* flush active streams */
  499         tcp_lro_rx_done(lc);
  500 
  501         lc->lro_mbuf_count = 0;
  502 }
  503 
  504 #ifdef INET6
  505 static int
  506 tcp_lro_rx_ipv6(struct lro_ctrl *lc, struct mbuf *m, struct ip6_hdr *ip6,
  507     struct tcphdr **th)
  508 {
  509 
  510         /* XXX-BZ we should check the flow-label. */
  511 
  512         /* XXX-BZ We do not yet support ext. hdrs. */
  513         if (ip6->ip6_nxt != IPPROTO_TCP)
  514                 return (TCP_LRO_NOT_SUPPORTED);
  515 
  516         /* Find the TCP header. */
  517         *th = (struct tcphdr *)(ip6 + 1);
  518 
  519         return (0);
  520 }
  521 #endif
  522 
  523 #ifdef INET
  524 static int
  525 tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4,
  526     struct tcphdr **th)
  527 {
  528         int csum_flags;
  529         uint16_t csum;
  530 
  531         if (ip4->ip_p != IPPROTO_TCP)
  532                 return (TCP_LRO_NOT_SUPPORTED);
  533 
  534         /* Ensure there are no options. */
  535         if ((ip4->ip_hl << 2) != sizeof (*ip4))
  536                 return (TCP_LRO_CANNOT);
  537 
  538         /* .. and the packet is not fragmented. */
  539         if (ip4->ip_off & htons(IP_MF|IP_OFFMASK))
  540                 return (TCP_LRO_CANNOT);
  541 
  542         /* Legacy IP has a header checksum that needs to be correct. */
  543         csum_flags = m->m_pkthdr.csum_flags;
  544         if (csum_flags & CSUM_IP_CHECKED) {
  545                 if (__predict_false((csum_flags & CSUM_IP_VALID) == 0)) {
  546                         lc->lro_bad_csum++;
  547                         return (TCP_LRO_CANNOT);
  548                 }
  549         } else {
  550                 csum = in_cksum_hdr(ip4);
  551                 if (__predict_false((csum) != 0)) {
  552                         lc->lro_bad_csum++;
  553                         return (TCP_LRO_CANNOT);
  554                 }
  555         }
  556 
  557         /* Find the TCP header (we assured there are no IP options). */
  558         *th = (struct tcphdr *)(ip4 + 1);
  559 
  560         return (0);
  561 }
  562 #endif
  563 
  564 int
  565 tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
  566 {
  567         struct lro_entry *le;
  568         struct ether_header *eh;
  569 #ifdef INET6
  570         struct ip6_hdr *ip6 = NULL;     /* Keep compiler happy. */
  571 #endif
  572 #ifdef INET
  573         struct ip *ip4 = NULL;          /* Keep compiler happy. */
  574 #endif
  575         struct tcphdr *th;
  576         void *l3hdr = NULL;             /* Keep compiler happy. */
  577         uint32_t *ts_ptr;
  578         tcp_seq seq;
  579         int error, ip_len, l;
  580         uint16_t eh_type, tcp_data_len;
  581 
  582         /* We expect a contiguous header [eh, ip, tcp]. */
  583 
  584         eh = mtod(m, struct ether_header *);
  585         eh_type = ntohs(eh->ether_type);
  586         switch (eh_type) {
  587 #ifdef INET6
  588         case ETHERTYPE_IPV6:
  589         {
  590                 CURVNET_SET(lc->ifp->if_vnet);
  591                 if (V_ip6_forwarding != 0) {
  592                         /* XXX-BZ stats but changing lro_ctrl is a problem. */
  593                         CURVNET_RESTORE();
  594                         return (TCP_LRO_CANNOT);
  595                 }
  596                 CURVNET_RESTORE();
  597                 l3hdr = ip6 = (struct ip6_hdr *)(eh + 1);
  598                 error = tcp_lro_rx_ipv6(lc, m, ip6, &th);
  599                 if (error != 0)
  600                         return (error);
  601                 tcp_data_len = ntohs(ip6->ip6_plen);
  602                 ip_len = sizeof(*ip6) + tcp_data_len;
  603                 break;
  604         }
  605 #endif
  606 #ifdef INET
  607         case ETHERTYPE_IP:
  608         {
  609                 CURVNET_SET(lc->ifp->if_vnet);
  610                 if (V_ipforwarding != 0) {
  611                         /* XXX-BZ stats but changing lro_ctrl is a problem. */
  612                         CURVNET_RESTORE();
  613                         return (TCP_LRO_CANNOT);
  614                 }
  615                 CURVNET_RESTORE();
  616                 l3hdr = ip4 = (struct ip *)(eh + 1);
  617                 error = tcp_lro_rx_ipv4(lc, m, ip4, &th);
  618                 if (error != 0)
  619                         return (error);
  620                 ip_len = ntohs(ip4->ip_len);
  621                 tcp_data_len = ip_len - sizeof(*ip4);
  622                 break;
  623         }
  624 #endif
  625         /* XXX-BZ what happens in case of VLAN(s)? */
  626         default:
  627                 return (TCP_LRO_NOT_SUPPORTED);
  628         }
  629 
  630         /*
  631          * If the frame is padded beyond the end of the IP packet, then we must
  632          * trim the extra bytes off.
  633          */
  634         l = m->m_pkthdr.len - (ETHER_HDR_LEN + ip_len);
  635         if (l != 0) {
  636                 if (l < 0)
  637                         /* Truncated packet. */
  638                         return (TCP_LRO_CANNOT);
  639 
  640                 m_adj(m, -l);
  641         }
  642 
  643         /*
  644          * Check TCP header constraints.
  645          */
  646         /* Ensure no bits set besides ACK or PSH. */
  647         if ((th->th_flags & ~(TH_ACK | TH_PUSH)) != 0)
  648                 return (TCP_LRO_CANNOT);
  649 
  650         /* XXX-BZ We lose a ACK|PUSH flag concatenating multiple segments. */
  651         /* XXX-BZ Ideally we'd flush on PUSH? */
  652 
  653         /*
  654          * Check for timestamps.
  655          * Since the only option we handle are timestamps, we only have to
  656          * handle the simple case of aligned timestamps.
  657          */
  658         l = (th->th_off << 2);
  659         tcp_data_len -= l;
  660         l -= sizeof(*th);
  661         ts_ptr = (uint32_t *)(th + 1);
  662         if (l != 0 && (__predict_false(l != TCPOLEN_TSTAMP_APPA) ||
  663             (*ts_ptr != ntohl(TCPOPT_NOP<<24|TCPOPT_NOP<<16|
  664             TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP))))
  665                 return (TCP_LRO_CANNOT);
  666 
  667         /* If the driver did not pass in the checksum, set it now. */
  668         if (csum == 0x0000)
  669                 csum = th->th_sum;
  670 
  671         seq = ntohl(th->th_seq);
  672 
  673         /* Try to find a matching previous segment. */
  674         LIST_FOREACH(le, &lc->lro_active, next) {
  675                 if (le->eh_type != eh_type)
  676                         continue;
  677                 if (le->source_port != th->th_sport ||
  678                     le->dest_port != th->th_dport)
  679                         continue;
  680                 switch (eh_type) {
  681 #ifdef INET6
  682                 case ETHERTYPE_IPV6:
  683                         if (bcmp(&le->source_ip6, &ip6->ip6_src,
  684                             sizeof(struct in6_addr)) != 0 ||
  685                             bcmp(&le->dest_ip6, &ip6->ip6_dst,
  686                             sizeof(struct in6_addr)) != 0)
  687                                 continue;
  688                         break;
  689 #endif
  690 #ifdef INET
  691                 case ETHERTYPE_IP:
  692                         if (le->source_ip4 != ip4->ip_src.s_addr ||
  693                             le->dest_ip4 != ip4->ip_dst.s_addr)
  694                                 continue;
  695                         break;
  696 #endif
  697                 }
  698 
  699                 /* Flush now if appending will result in overflow. */
  700                 if (le->p_len > (lc->lro_length_lim - tcp_data_len)) {
  701                         tcp_lro_active_remove(le);
  702                         tcp_lro_flush(lc, le);
  703                         break;
  704                 }
  705 
  706                 /* Try to append the new segment. */
  707                 if (__predict_false(seq != le->next_seq ||
  708                     (tcp_data_len == 0 && le->ack_seq == th->th_ack))) {
  709                         /* Out of order packet or duplicate ACK. */
  710                         tcp_lro_active_remove(le);
  711                         tcp_lro_flush(lc, le);
  712                         return (TCP_LRO_CANNOT);
  713                 }
  714 
  715                 if (l != 0) {
  716                         uint32_t tsval = ntohl(*(ts_ptr + 1));
  717                         /* Make sure timestamp values are increasing. */
  718                         /* XXX-BZ flip and use TSTMP_GEQ macro for this? */
  719                         if (__predict_false(le->tsval > tsval ||
  720                             *(ts_ptr + 2) == 0))
  721                                 return (TCP_LRO_CANNOT);
  722                         le->tsval = tsval;
  723                         le->tsecr = *(ts_ptr + 2);
  724                 }
  725 
  726                 le->next_seq += tcp_data_len;
  727                 le->ack_seq = th->th_ack;
  728                 le->window = th->th_win;
  729                 le->append_cnt++;
  730 
  731 #ifdef TCP_LRO_UPDATE_CSUM
  732                 le->ulp_csum += tcp_lro_rx_csum_fixup(le, l3hdr, th,
  733                     tcp_data_len, ~csum);
  734 #endif
  735 
  736                 if (tcp_data_len == 0) {
  737                         m_freem(m);
  738                         /*
  739                          * Flush this LRO entry, if this ACK should not
  740                          * be further delayed.
  741                          */
  742                         if (le->append_cnt >= lc->lro_ackcnt_lim) {
  743                                 tcp_lro_active_remove(le);
  744                                 tcp_lro_flush(lc, le);
  745                         }
  746                         return (0);
  747                 }
  748 
  749                 le->p_len += tcp_data_len;
  750 
  751                 /*
  752                  * Adjust the mbuf so that m_data points to the first byte of
  753                  * the ULP payload.  Adjust the mbuf to avoid complications and
  754                  * append new segment to existing mbuf chain.
  755                  */
  756                 m_adj(m, m->m_pkthdr.len - tcp_data_len);
  757                 m_demote_pkthdr(m);
  758 
  759                 le->m_tail->m_next = m;
  760                 le->m_tail = m_last(m);
  761 
  762                 /*
  763                  * If a possible next full length packet would cause an
  764                  * overflow, pro-actively flush now.
  765                  */
  766                 if (le->p_len > (lc->lro_length_lim - lc->ifp->if_mtu)) {
  767                         tcp_lro_active_remove(le);
  768                         tcp_lro_flush(lc, le);
  769                 } else
  770                         getmicrotime(&le->mtime);
  771 
  772                 return (0);
  773         }
  774 
  775         /* Try to find an empty slot. */
  776         if (LIST_EMPTY(&lc->lro_free))
  777                 return (TCP_LRO_NO_ENTRIES);
  778 
  779         /* Start a new segment chain. */
  780         le = LIST_FIRST(&lc->lro_free);
  781         LIST_REMOVE(le, next);
  782         tcp_lro_active_insert(lc, le);
  783         getmicrotime(&le->mtime);
  784 
  785         /* Start filling in details. */
  786         switch (eh_type) {
  787 #ifdef INET6
  788         case ETHERTYPE_IPV6:
  789                 le->le_ip6 = ip6;
  790                 le->source_ip6 = ip6->ip6_src;
  791                 le->dest_ip6 = ip6->ip6_dst;
  792                 le->eh_type = eh_type;
  793                 le->p_len = m->m_pkthdr.len - ETHER_HDR_LEN - sizeof(*ip6);
  794                 break;
  795 #endif
  796 #ifdef INET
  797         case ETHERTYPE_IP:
  798                 le->le_ip4 = ip4;
  799                 le->source_ip4 = ip4->ip_src.s_addr;
  800                 le->dest_ip4 = ip4->ip_dst.s_addr;
  801                 le->eh_type = eh_type;
  802                 le->p_len = m->m_pkthdr.len - ETHER_HDR_LEN;
  803                 break;
  804 #endif
  805         }
  806         le->source_port = th->th_sport;
  807         le->dest_port = th->th_dport;
  808 
  809         le->next_seq = seq + tcp_data_len;
  810         le->ack_seq = th->th_ack;
  811         le->window = th->th_win;
  812         if (l != 0) {
  813                 le->timestamp = 1;
  814                 le->tsval = ntohl(*(ts_ptr + 1));
  815                 le->tsecr = *(ts_ptr + 2);
  816         }
  817 
  818 #ifdef TCP_LRO_UPDATE_CSUM
  819         /*
  820          * Do not touch the csum of the first packet.  However save the
  821          * "adjusted" checksum of just the source and destination addresses,
  822          * the next header and the TCP payload.  The length and TCP header
  823          * parts may change, so we remove those from the saved checksum and
  824          * re-add with final values on tcp_lro_flush() if needed.
  825          */
  826         KASSERT(le->ulp_csum == 0, ("%s: le=%p le->ulp_csum=0x%04x\n",
  827             __func__, le, le->ulp_csum));
  828 
  829         le->ulp_csum = tcp_lro_rx_csum_fixup(le, l3hdr, th, tcp_data_len,
  830             ~csum);
  831         th->th_sum = csum;      /* Restore checksum on first packet. */
  832 #endif
  833 
  834         le->m_head = m;
  835         le->m_tail = m_last(m);
  836 
  837         return (0);
  838 }
  839 
  840 void
  841 tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb)
  842 {
  843         /* sanity checks */
  844         if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL ||
  845             lc->lro_mbuf_max == 0)) {
  846                 /* packet drop */
  847                 m_freem(mb);
  848                 return;
  849         }
  850 
  851         /* check if packet is not LRO capable */
  852         if (__predict_false(mb->m_pkthdr.csum_flags == 0 ||
  853             (lc->ifp->if_capenable & IFCAP_LRO) == 0)) {
  854                 lc->lro_flushed++;
  855                 lc->lro_queued++;
  856 
  857                 /* input packet to network layer */
  858                 (*lc->ifp->if_input) (lc->ifp, mb);
  859                 return;
  860         }
  861 
  862         /* check if array is full */
  863         if (__predict_false(lc->lro_mbuf_count == lc->lro_mbuf_max))
  864                 tcp_lro_flush_all(lc);
  865 
  866         /* create sequence number */
  867         lc->lro_mbuf_data[lc->lro_mbuf_count].seq =
  868             (((uint64_t)M_HASHTYPE_GET(mb)) << 56) |
  869             (((uint64_t)mb->m_pkthdr.flowid) << 24) |
  870             ((uint64_t)lc->lro_mbuf_count);
  871 
  872         /* enter mbuf */
  873         lc->lro_mbuf_data[lc->lro_mbuf_count++].mb = mb;
  874 }
  875 
  876 /* 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
