The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/dev/iscsi/icl_soft.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2012 The FreeBSD Foundation
    5  *
    6  * This software was developed by Edward Tomasz Napierala under sponsorship
    7  * from the FreeBSD Foundation.
    8  *
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  *
   30  */
   31 
   32 /*
   33  * Software implementation of iSCSI Common Layer kobj(9) interface.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD$");
   38 
   39 #include <sys/param.h>
   40 #include <sys/bio.h>
   41 #include <sys/capsicum.h>
   42 #include <sys/condvar.h>
   43 #include <sys/conf.h>
   44 #include <sys/gsb_crc32.h>
   45 #include <sys/file.h>
   46 #include <sys/kernel.h>
   47 #include <sys/kthread.h>
   48 #include <sys/lock.h>
   49 #include <sys/mbuf.h>
   50 #include <sys/mutex.h>
   51 #include <sys/module.h>
   52 #include <sys/protosw.h>
   53 #include <sys/socket.h>
   54 #include <sys/socketvar.h>
   55 #include <sys/sysctl.h>
   56 #include <sys/systm.h>
   57 #include <sys/sx.h>
   58 #include <sys/uio.h>
   59 #include <vm/uma.h>
   60 #include <vm/vm_page.h>
   61 #include <netinet/in.h>
   62 #include <netinet/tcp.h>
   63 
   64 #include <dev/iscsi/icl.h>
   65 #include <dev/iscsi/iscsi_proto.h>
   66 #include <icl_conn_if.h>
   67 
   68 #define ICL_CONN_STATE_BHS              1
   69 #define ICL_CONN_STATE_AHS              2
   70 #define ICL_CONN_STATE_HEADER_DIGEST    3
   71 #define ICL_CONN_STATE_DATA             4
   72 #define ICL_CONN_STATE_DATA_DIGEST      5
   73 
   74 struct icl_soft_conn {
   75         struct icl_conn  ic;
   76 
   77         /* soft specific stuff goes here. */
   78         STAILQ_HEAD(, icl_pdu) to_send;
   79         struct cv        send_cv;
   80         struct cv        receive_cv;
   81         struct icl_pdu  *receive_pdu;
   82         size_t           receive_len;
   83         int              receive_state;
   84         bool             receive_running;
   85         bool             check_send_space;
   86         bool             send_running;
   87 };
   88 
   89 struct icl_soft_pdu {
   90         struct icl_pdu   ip;
   91 
   92         /* soft specific stuff goes here. */
   93         u_int            ref_cnt;
   94         icl_pdu_cb       cb;
   95         int              error;
   96 };
   97 
   98 SYSCTL_NODE(_kern_icl, OID_AUTO, soft, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
   99     "Software iSCSI");
  100 static int coalesce = 1;
  101 SYSCTL_INT(_kern_icl_soft, OID_AUTO, coalesce, CTLFLAG_RWTUN,
  102     &coalesce, 0, "Try to coalesce PDUs before sending");
  103 static int partial_receive_len = 256 * 1024;
  104 SYSCTL_INT(_kern_icl_soft, OID_AUTO, partial_receive_len, CTLFLAG_RWTUN,
  105     &partial_receive_len, 0, "Minimum read size for partially received "
  106     "data segment");
  107 static int max_data_segment_length = 256 * 1024;
  108 SYSCTL_INT(_kern_icl_soft, OID_AUTO, max_data_segment_length, CTLFLAG_RWTUN,
  109     &max_data_segment_length, 0, "Maximum data segment length");
  110 static int first_burst_length = 1024 * 1024;
  111 SYSCTL_INT(_kern_icl_soft, OID_AUTO, first_burst_length, CTLFLAG_RWTUN,
  112     &first_burst_length, 0, "First burst length");
  113 static int max_burst_length = 1024 * 1024;
  114 SYSCTL_INT(_kern_icl_soft, OID_AUTO, max_burst_length, CTLFLAG_RWTUN,
  115     &max_burst_length, 0, "Maximum burst length");
  116 static int sendspace = 1536 * 1024;
  117 SYSCTL_INT(_kern_icl_soft, OID_AUTO, sendspace, CTLFLAG_RWTUN,
  118     &sendspace, 0, "Default send socket buffer size");
  119 static int recvspace = 1536 * 1024;
  120 SYSCTL_INT(_kern_icl_soft, OID_AUTO, recvspace, CTLFLAG_RWTUN,
  121     &recvspace, 0, "Default receive socket buffer size");
  122 
  123 static MALLOC_DEFINE(M_ICL_SOFT, "icl_soft", "iSCSI software backend");
  124 static uma_zone_t icl_soft_pdu_zone;
  125 
  126 static volatile u_int   icl_ncons;
  127 
  128 STAILQ_HEAD(icl_pdu_stailq, icl_pdu);
  129 
  130 static icl_conn_new_pdu_t       icl_soft_conn_new_pdu;
  131 static icl_conn_pdu_free_t      icl_soft_conn_pdu_free;
  132 static icl_conn_pdu_data_segment_length_t
  133                                     icl_soft_conn_pdu_data_segment_length;
  134 static icl_conn_pdu_append_bio_t        icl_soft_conn_pdu_append_bio;
  135 static icl_conn_pdu_append_data_t       icl_soft_conn_pdu_append_data;
  136 static icl_conn_pdu_get_bio_t   icl_soft_conn_pdu_get_bio;
  137 static icl_conn_pdu_get_data_t  icl_soft_conn_pdu_get_data;
  138 static icl_conn_pdu_queue_t     icl_soft_conn_pdu_queue;
  139 static icl_conn_pdu_queue_cb_t  icl_soft_conn_pdu_queue_cb;
  140 static icl_conn_handoff_t       icl_soft_conn_handoff;
  141 static icl_conn_free_t          icl_soft_conn_free;
  142 static icl_conn_close_t         icl_soft_conn_close;
  143 static icl_conn_task_setup_t    icl_soft_conn_task_setup;
  144 static icl_conn_task_done_t     icl_soft_conn_task_done;
  145 static icl_conn_transfer_setup_t        icl_soft_conn_transfer_setup;
  146 static icl_conn_transfer_done_t icl_soft_conn_transfer_done;
  147 #ifdef ICL_KERNEL_PROXY
  148 static icl_conn_connect_t       icl_soft_conn_connect;
  149 #endif
  150 
  151 static kobj_method_t icl_soft_methods[] = {
  152         KOBJMETHOD(icl_conn_new_pdu, icl_soft_conn_new_pdu),
  153         KOBJMETHOD(icl_conn_pdu_free, icl_soft_conn_pdu_free),
  154         KOBJMETHOD(icl_conn_pdu_data_segment_length,
  155             icl_soft_conn_pdu_data_segment_length),
  156         KOBJMETHOD(icl_conn_pdu_append_bio, icl_soft_conn_pdu_append_bio),
  157         KOBJMETHOD(icl_conn_pdu_append_data, icl_soft_conn_pdu_append_data),
  158         KOBJMETHOD(icl_conn_pdu_get_bio, icl_soft_conn_pdu_get_bio),
  159         KOBJMETHOD(icl_conn_pdu_get_data, icl_soft_conn_pdu_get_data),
  160         KOBJMETHOD(icl_conn_pdu_queue, icl_soft_conn_pdu_queue),
  161         KOBJMETHOD(icl_conn_pdu_queue_cb, icl_soft_conn_pdu_queue_cb),
  162         KOBJMETHOD(icl_conn_handoff, icl_soft_conn_handoff),
  163         KOBJMETHOD(icl_conn_free, icl_soft_conn_free),
  164         KOBJMETHOD(icl_conn_close, icl_soft_conn_close),
  165         KOBJMETHOD(icl_conn_task_setup, icl_soft_conn_task_setup),
  166         KOBJMETHOD(icl_conn_task_done, icl_soft_conn_task_done),
  167         KOBJMETHOD(icl_conn_transfer_setup, icl_soft_conn_transfer_setup),
  168         KOBJMETHOD(icl_conn_transfer_done, icl_soft_conn_transfer_done),
  169 #ifdef ICL_KERNEL_PROXY
  170         KOBJMETHOD(icl_conn_connect, icl_soft_conn_connect),
  171 #endif
  172         { 0, 0 }
  173 };
  174 
  175 DEFINE_CLASS(icl_soft, icl_soft_methods, sizeof(struct icl_soft_conn));
  176 
  177 static void
  178 icl_conn_fail(struct icl_conn *ic)
  179 {
  180         if (ic->ic_socket == NULL)
  181                 return;
  182 
  183         /*
  184          * XXX
  185          */
  186         ic->ic_socket->so_error = EDOOFUS;
  187         (ic->ic_error)(ic);
  188 }
  189 
  190 static void
  191 icl_soft_conn_pdu_free(struct icl_conn *ic, struct icl_pdu *ip)
  192 {
  193         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)ip;
  194 
  195         KASSERT(isp->ref_cnt == 0, ("freeing active PDU"));
  196         m_freem(ip->ip_bhs_mbuf);
  197         m_freem(ip->ip_ahs_mbuf);
  198         m_freem(ip->ip_data_mbuf);
  199         uma_zfree(icl_soft_pdu_zone, isp);
  200 #ifdef DIAGNOSTIC
  201         refcount_release(&ic->ic_outstanding_pdus);
  202 #endif
  203 }
  204 
  205 static void
  206 icl_soft_pdu_call_cb(struct icl_pdu *ip)
  207 {
  208         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)ip;
  209 
  210         if (isp->cb != NULL)
  211                 isp->cb(ip, isp->error);
  212 #ifdef DIAGNOSTIC
  213         refcount_release(&ip->ip_conn->ic_outstanding_pdus);
  214 #endif
  215         uma_zfree(icl_soft_pdu_zone, isp);
  216 }
  217 
  218 static void
  219 icl_soft_pdu_done(struct icl_pdu *ip, int error)
  220 {
  221         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)ip;
  222 
  223         if (error != 0)
  224                 isp->error = error;
  225 
  226         m_freem(ip->ip_bhs_mbuf);
  227         ip->ip_bhs_mbuf = NULL;
  228         m_freem(ip->ip_ahs_mbuf);
  229         ip->ip_ahs_mbuf = NULL;
  230         m_freem(ip->ip_data_mbuf);
  231         ip->ip_data_mbuf = NULL;
  232 
  233         if (atomic_fetchadd_int(&isp->ref_cnt, -1) == 1)
  234                 icl_soft_pdu_call_cb(ip);
  235 }
  236 
  237 static void
  238 icl_soft_mbuf_done(struct mbuf *mb)
  239 {
  240         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)mb->m_ext.ext_arg1;
  241 
  242         icl_soft_pdu_call_cb(&isp->ip);
  243 }
  244 
  245 /*
  246  * Allocate icl_pdu with empty BHS to fill up by the caller.
  247  */
  248 struct icl_pdu *
  249 icl_soft_conn_new_pdu(struct icl_conn *ic, int flags)
  250 {
  251         struct icl_soft_pdu *isp;
  252         struct icl_pdu *ip;
  253 
  254 #ifdef DIAGNOSTIC
  255         refcount_acquire(&ic->ic_outstanding_pdus);
  256 #endif
  257         isp = uma_zalloc(icl_soft_pdu_zone, flags | M_ZERO);
  258         if (isp == NULL) {
  259                 ICL_WARN("failed to allocate soft PDU");
  260 #ifdef DIAGNOSTIC
  261                 refcount_release(&ic->ic_outstanding_pdus);
  262 #endif
  263                 return (NULL);
  264         }
  265         ip = &isp->ip;
  266         ip->ip_conn = ic;
  267 
  268         CTASSERT(sizeof(struct iscsi_bhs) <= MHLEN);
  269         ip->ip_bhs_mbuf = m_gethdr(flags, MT_DATA);
  270         if (ip->ip_bhs_mbuf == NULL) {
  271                 ICL_WARN("failed to allocate BHS mbuf");
  272                 icl_soft_conn_pdu_free(ic, ip);
  273                 return (NULL);
  274         }
  275         ip->ip_bhs = mtod(ip->ip_bhs_mbuf, struct iscsi_bhs *);
  276         memset(ip->ip_bhs, 0, sizeof(struct iscsi_bhs));
  277         ip->ip_bhs_mbuf->m_len = sizeof(struct iscsi_bhs);
  278 
  279         return (ip);
  280 }
  281 
  282 static int
  283 icl_pdu_ahs_length(const struct icl_pdu *request)
  284 {
  285 
  286         return (request->ip_bhs->bhs_total_ahs_len * 4);
  287 }
  288 
  289 static size_t
  290 icl_pdu_data_segment_length(const struct icl_pdu *request)
  291 {
  292         uint32_t len = 0;
  293 
  294         len += request->ip_bhs->bhs_data_segment_len[0];
  295         len <<= 8;
  296         len += request->ip_bhs->bhs_data_segment_len[1];
  297         len <<= 8;
  298         len += request->ip_bhs->bhs_data_segment_len[2];
  299 
  300         return (len);
  301 }
  302 
  303 size_t
  304 icl_soft_conn_pdu_data_segment_length(struct icl_conn *ic,
  305     const struct icl_pdu *request)
  306 {
  307 
  308         return (icl_pdu_data_segment_length(request));
  309 }
  310 
  311 static void
  312 icl_pdu_set_data_segment_length(struct icl_pdu *response, uint32_t len)
  313 {
  314 
  315         response->ip_bhs->bhs_data_segment_len[2] = len;
  316         response->ip_bhs->bhs_data_segment_len[1] = len >> 8;
  317         response->ip_bhs->bhs_data_segment_len[0] = len >> 16;
  318 }
  319 
  320 static size_t
  321 icl_pdu_padding(const struct icl_pdu *ip)
  322 {
  323 
  324         if ((ip->ip_data_len % 4) != 0)
  325                 return (4 - (ip->ip_data_len % 4));
  326 
  327         return (0);
  328 }
  329 
  330 static size_t
  331 icl_pdu_size(const struct icl_pdu *response)
  332 {
  333         size_t len;
  334 
  335         KASSERT(response->ip_ahs_len == 0, ("responding with AHS"));
  336 
  337         len = sizeof(struct iscsi_bhs) + response->ip_data_len +
  338             icl_pdu_padding(response);
  339         if (response->ip_conn->ic_header_crc32c)
  340                 len += ISCSI_HEADER_DIGEST_SIZE;
  341         if (response->ip_data_len != 0 && response->ip_conn->ic_data_crc32c)
  342                 len += ISCSI_DATA_DIGEST_SIZE;
  343 
  344         return (len);
  345 }
  346 
  347 static void
  348 icl_soft_receive_buf(struct mbuf **r, size_t *rs, void *buf, size_t s)
  349 {
  350 
  351         m_copydata(*r, 0, s, buf);
  352         m_adj(*r, s);
  353         while ((*r) != NULL && (*r)->m_len == 0)
  354                 *r = m_free(*r);
  355         *rs -= s;
  356 }
  357 
  358 static void
  359 icl_pdu_receive_ahs(struct icl_pdu *request, struct mbuf **r, size_t *rs)
  360 {
  361 
  362         request->ip_ahs_len = icl_pdu_ahs_length(request);
  363         if (request->ip_ahs_len == 0)
  364                 return;
  365 
  366         request->ip_ahs_mbuf = *r;
  367         *r = m_split(request->ip_ahs_mbuf, request->ip_ahs_len, M_WAITOK);
  368         *rs -= request->ip_ahs_len;
  369 }
  370 
  371 static int
  372 mbuf_crc32c_helper(void *arg, void *data, u_int len)
  373 {
  374         uint32_t *digestp = arg;
  375 
  376         *digestp = calculate_crc32c(*digestp, data, len);
  377         return (0);
  378 }
  379 
  380 static uint32_t
  381 icl_mbuf_to_crc32c(struct mbuf *m0, size_t len)
  382 {
  383         uint32_t digest = 0xffffffff;
  384 
  385         m_apply(m0, 0, len, mbuf_crc32c_helper, &digest);
  386         digest = digest ^ 0xffffffff;
  387 
  388         return (digest);
  389 }
  390 
  391 static int
  392 icl_pdu_check_header_digest(struct icl_pdu *request, struct mbuf **r, size_t *rs)
  393 {
  394         uint32_t received_digest, valid_digest;
  395 
  396         if (request->ip_conn->ic_header_crc32c == false)
  397                 return (0);
  398 
  399         CTASSERT(sizeof(received_digest) == ISCSI_HEADER_DIGEST_SIZE);
  400         icl_soft_receive_buf(r, rs, &received_digest, ISCSI_HEADER_DIGEST_SIZE);
  401 
  402         /* Temporary attach AHS to BHS to calculate header digest. */
  403         request->ip_bhs_mbuf->m_next = request->ip_ahs_mbuf;
  404         valid_digest = icl_mbuf_to_crc32c(request->ip_bhs_mbuf, ISCSI_BHS_SIZE);
  405         request->ip_bhs_mbuf->m_next = NULL;
  406         if (received_digest != valid_digest) {
  407                 ICL_WARN("header digest check failed; got 0x%x, "
  408                     "should be 0x%x", received_digest, valid_digest);
  409                 return (-1);
  410         }
  411 
  412         return (0);
  413 }
  414 
  415 /*
  416  * Return the number of bytes that should be waiting in the receive socket
  417  * before icl_pdu_receive_data_segment() gets called.
  418  */
  419 static size_t
  420 icl_pdu_data_segment_receive_len(const struct icl_pdu *request)
  421 {
  422         size_t len;
  423 
  424         len = icl_pdu_data_segment_length(request);
  425         if (len == 0)
  426                 return (0);
  427 
  428         /*
  429          * Account for the parts of data segment already read from
  430          * the socket buffer.
  431          */
  432         KASSERT(len > request->ip_data_len, ("len <= request->ip_data_len"));
  433         len -= request->ip_data_len;
  434 
  435         /*
  436          * Don't always wait for the full data segment to be delivered
  437          * to the socket; this might badly affect performance due to
  438          * TCP window scaling.
  439          */
  440         if (len > partial_receive_len) {
  441 #if 0
  442                 ICL_DEBUG("need %zd bytes of data, limiting to %zd",
  443                     len, partial_receive_len));
  444 #endif
  445                 len = partial_receive_len;
  446 
  447                 return (len);
  448         }
  449 
  450         /*
  451          * Account for padding.  Note that due to the way code is written,
  452          * the icl_pdu_receive_data_segment() must always receive padding
  453          * along with the last part of data segment, because it would be
  454          * impossible to tell whether we've already received the full data
  455          * segment including padding, or without it.
  456          */
  457         if ((len % 4) != 0)
  458                 len += 4 - (len % 4);
  459 
  460 #if 0
  461         ICL_DEBUG("need %zd bytes of data", len));
  462 #endif
  463 
  464         return (len);
  465 }
  466 
  467 static int
  468 icl_pdu_receive_data_segment(struct icl_pdu *request, struct mbuf **r,
  469     size_t *rs, bool *more_neededp)
  470 {
  471         struct icl_soft_conn *isc;
  472         size_t len, padding = 0;
  473         struct mbuf *m;
  474 
  475         isc = (struct icl_soft_conn *)request->ip_conn;
  476 
  477         *more_neededp = false;
  478         isc->receive_len = 0;
  479 
  480         len = icl_pdu_data_segment_length(request);
  481         if (len == 0)
  482                 return (0);
  483 
  484         if ((len % 4) != 0)
  485                 padding = 4 - (len % 4);
  486 
  487         /*
  488          * Account for already received parts of data segment.
  489          */
  490         KASSERT(len > request->ip_data_len, ("len <= request->ip_data_len"));
  491         len -= request->ip_data_len;
  492 
  493         if (len + padding > *rs) {
  494                 /*
  495                  * Not enough data in the socket buffer.  Receive as much
  496                  * as we can.  Don't receive padding, since, obviously, it's
  497                  * not the end of data segment yet.
  498                  */
  499 #if 0
  500                 ICL_DEBUG("limited from %zd to %zd",
  501                     len + padding, *rs - padding));
  502 #endif
  503                 len = *rs - padding;
  504                 *more_neededp = true;
  505                 padding = 0;
  506         }
  507 
  508         /*
  509          * Must not try to receive padding without at least one byte
  510          * of actual data segment.
  511          */
  512         if (len > 0) {
  513                 m = *r;
  514                 *r = m_split(m, len + padding, M_WAITOK);
  515                 *rs -= len + padding;
  516 
  517                 if (request->ip_data_mbuf == NULL)
  518                         request->ip_data_mbuf = m;
  519                 else
  520                         m_cat(request->ip_data_mbuf, m);
  521 
  522                 request->ip_data_len += len;
  523         } else
  524                 ICL_DEBUG("len 0");
  525 
  526         if (*more_neededp)
  527                 isc->receive_len = icl_pdu_data_segment_receive_len(request);
  528 
  529         return (0);
  530 }
  531 
  532 static int
  533 icl_pdu_check_data_digest(struct icl_pdu *request, struct mbuf **r, size_t *rs)
  534 {
  535         uint32_t received_digest, valid_digest;
  536 
  537         if (request->ip_conn->ic_data_crc32c == false)
  538                 return (0);
  539 
  540         if (request->ip_data_len == 0)
  541                 return (0);
  542 
  543         CTASSERT(sizeof(received_digest) == ISCSI_DATA_DIGEST_SIZE);
  544         icl_soft_receive_buf(r, rs, &received_digest, ISCSI_DATA_DIGEST_SIZE);
  545 
  546         /*
  547          * Note that ip_data_mbuf also contains padding; since digest
  548          * calculation is supposed to include that, we iterate over
  549          * the entire ip_data_mbuf chain, not just ip_data_len bytes of it.
  550          */
  551         valid_digest = icl_mbuf_to_crc32c(request->ip_data_mbuf,
  552             roundup2(request->ip_data_len, 4));
  553         if (received_digest != valid_digest) {
  554                 ICL_WARN("data digest check failed; got 0x%x, "
  555                     "should be 0x%x", received_digest, valid_digest);
  556                 return (-1);
  557         }
  558 
  559         return (0);
  560 }
  561 
  562 /*
  563  * Somewhat contrary to the name, this attempts to receive only one
  564  * "part" of PDU at a time; call it repeatedly until it returns non-NULL.
  565  */
  566 static struct icl_pdu *
  567 icl_conn_receive_pdu(struct icl_soft_conn *isc, struct mbuf **r, size_t *rs)
  568 {
  569         struct icl_conn *ic = &isc->ic;
  570         struct icl_pdu *request;
  571         size_t len;
  572         int error = 0;
  573         bool more_needed;
  574 
  575         if (isc->receive_state == ICL_CONN_STATE_BHS) {
  576                 KASSERT(isc->receive_pdu == NULL,
  577                     ("isc->receive_pdu != NULL"));
  578                 request = icl_soft_conn_new_pdu(ic, M_NOWAIT);
  579                 if (request == NULL) {
  580                         ICL_DEBUG("failed to allocate PDU; "
  581                             "dropping connection");
  582                         icl_conn_fail(ic);
  583                         return (NULL);
  584                 }
  585                 isc->receive_pdu = request;
  586         } else {
  587                 KASSERT(isc->receive_pdu != NULL,
  588                     ("isc->receive_pdu == NULL"));
  589                 request = isc->receive_pdu;
  590         }
  591 
  592         switch (isc->receive_state) {
  593         case ICL_CONN_STATE_BHS:
  594                 //ICL_DEBUG("receiving BHS");
  595                 icl_soft_receive_buf(r, rs, request->ip_bhs,
  596                     sizeof(struct iscsi_bhs));
  597 
  598                 /*
  599                  * We don't enforce any limit for AHS length;
  600                  * its length is stored in 8 bit field.
  601                  */
  602 
  603                 len = icl_pdu_data_segment_length(request);
  604                 if (len > ic->ic_max_recv_data_segment_length) {
  605                         ICL_WARN("received data segment "
  606                             "length %zd is larger than negotiated; "
  607                             "dropping connection", len);
  608                         error = EINVAL;
  609                         break;
  610                 }
  611 
  612                 isc->receive_state = ICL_CONN_STATE_AHS;
  613                 isc->receive_len = icl_pdu_ahs_length(request);
  614                 break;
  615 
  616         case ICL_CONN_STATE_AHS:
  617                 //ICL_DEBUG("receiving AHS");
  618                 icl_pdu_receive_ahs(request, r, rs);
  619                 isc->receive_state = ICL_CONN_STATE_HEADER_DIGEST;
  620                 if (ic->ic_header_crc32c == false)
  621                         isc->receive_len = 0;
  622                 else
  623                         isc->receive_len = ISCSI_HEADER_DIGEST_SIZE;
  624                 break;
  625 
  626         case ICL_CONN_STATE_HEADER_DIGEST:
  627                 //ICL_DEBUG("receiving header digest");
  628                 error = icl_pdu_check_header_digest(request, r, rs);
  629                 if (error != 0) {
  630                         ICL_DEBUG("header digest failed; "
  631                             "dropping connection");
  632                         break;
  633                 }
  634 
  635                 isc->receive_state = ICL_CONN_STATE_DATA;
  636                 isc->receive_len = icl_pdu_data_segment_receive_len(request);
  637                 break;
  638 
  639         case ICL_CONN_STATE_DATA:
  640                 //ICL_DEBUG("receiving data segment");
  641                 error = icl_pdu_receive_data_segment(request, r, rs,
  642                     &more_needed);
  643                 if (error != 0) {
  644                         ICL_DEBUG("failed to receive data segment;"
  645                             "dropping connection");
  646                         break;
  647                 }
  648 
  649                 if (more_needed)
  650                         break;
  651 
  652                 isc->receive_state = ICL_CONN_STATE_DATA_DIGEST;
  653                 if (request->ip_data_len == 0 || ic->ic_data_crc32c == false)
  654                         isc->receive_len = 0;
  655                 else
  656                         isc->receive_len = ISCSI_DATA_DIGEST_SIZE;
  657                 break;
  658 
  659         case ICL_CONN_STATE_DATA_DIGEST:
  660                 //ICL_DEBUG("receiving data digest");
  661                 error = icl_pdu_check_data_digest(request, r, rs);
  662                 if (error != 0) {
  663                         ICL_DEBUG("data digest failed; "
  664                             "dropping connection");
  665                         break;
  666                 }
  667 
  668                 /*
  669                  * We've received complete PDU; reset the receive state machine
  670                  * and return the PDU.
  671                  */
  672                 isc->receive_state = ICL_CONN_STATE_BHS;
  673                 isc->receive_len = sizeof(struct iscsi_bhs);
  674                 isc->receive_pdu = NULL;
  675                 return (request);
  676 
  677         default:
  678                 panic("invalid receive_state %d\n", isc->receive_state);
  679         }
  680 
  681         if (error != 0) {
  682                 /*
  683                  * Don't free the PDU; it's pointed to by isc->receive_pdu
  684                  * and will get freed in icl_soft_conn_close().
  685                  */
  686                 icl_conn_fail(ic);
  687         }
  688 
  689         return (NULL);
  690 }
  691 
  692 static void
  693 icl_conn_receive_pdus(struct icl_soft_conn *isc, struct mbuf **r, size_t *rs)
  694 {
  695         struct icl_conn *ic = &isc->ic;
  696         struct icl_pdu *response;
  697 
  698         for (;;) {
  699                 if (ic->ic_disconnecting)
  700                         return;
  701 
  702                 /*
  703                  * Loop until we have a complete PDU or there is not enough
  704                  * data in the socket buffer.
  705                  */
  706                 if (*rs < isc->receive_len) {
  707 #if 0
  708                         ICL_DEBUG("not enough data; have %zd, need %zd",
  709                             *rs, isc->receive_len);
  710 #endif
  711                         return;
  712                 }
  713 
  714                 response = icl_conn_receive_pdu(isc, r, rs);
  715                 if (response == NULL)
  716                         continue;
  717 
  718                 if (response->ip_ahs_len > 0) {
  719                         ICL_WARN("received PDU with unsupported "
  720                             "AHS; opcode 0x%x; dropping connection",
  721                             response->ip_bhs->bhs_opcode);
  722                         icl_soft_conn_pdu_free(ic, response);
  723                         icl_conn_fail(ic);
  724                         return;
  725                 }
  726 
  727                 (ic->ic_receive)(response);
  728         }
  729 }
  730 
  731 static void
  732 icl_receive_thread(void *arg)
  733 {
  734         struct icl_soft_conn *isc = arg;
  735         struct icl_conn *ic = &isc->ic;
  736         size_t available, read = 0;
  737         struct socket *so;
  738         struct mbuf *m, *r = NULL;
  739         struct uio uio;
  740         int error, flags;
  741 
  742         so = ic->ic_socket;
  743 
  744         for (;;) {
  745                 SOCKBUF_LOCK(&so->so_rcv);
  746                 if (ic->ic_disconnecting) {
  747                         SOCKBUF_UNLOCK(&so->so_rcv);
  748                         break;
  749                 }
  750 
  751                 /*
  752                  * Set the low watermark, to be checked by
  753                  * soreadable() in icl_soupcall_receive()
  754                  * to avoid unnecessary wakeups until there
  755                  * is enough data received to read the PDU.
  756                  */
  757                 available = sbavail(&so->so_rcv);
  758                 if (read + available < isc->receive_len) {
  759                         so->so_rcv.sb_lowat = isc->receive_len - read;
  760                         cv_wait(&isc->receive_cv, SOCKBUF_MTX(&so->so_rcv));
  761                         so->so_rcv.sb_lowat = so->so_rcv.sb_hiwat + 1;
  762                         available = sbavail(&so->so_rcv);
  763                 }
  764                 SOCKBUF_UNLOCK(&so->so_rcv);
  765 
  766                 if (available == 0) {
  767                         if (so->so_error != 0) {
  768                                 ICL_DEBUG("connection error %d; "
  769                                     "dropping connection", so->so_error);
  770                                 icl_conn_fail(ic);
  771                                 break;
  772                         }
  773                         continue;
  774                 }
  775 
  776                 memset(&uio, 0, sizeof(uio));
  777                 uio.uio_resid = available;
  778                 flags = MSG_DONTWAIT;
  779                 error = soreceive(so, NULL, &uio, &m, NULL, &flags);
  780                 if (error != 0) {
  781                         ICL_DEBUG("soreceive error %d", error);
  782                         break;
  783                 }
  784                 if (uio.uio_resid != 0) {
  785                         m_freem(m);
  786                         ICL_DEBUG("short read");
  787                         break;
  788                 }
  789                 if (r)
  790                         m_cat(r, m);
  791                 else
  792                         r = m;
  793                 read += available;
  794 
  795                 icl_conn_receive_pdus(isc, &r, &read);
  796         }
  797 
  798         if (r)
  799                 m_freem(r);
  800 
  801         ICL_CONN_LOCK(ic);
  802         isc->receive_running = false;
  803         cv_signal(&isc->send_cv);
  804         ICL_CONN_UNLOCK(ic);
  805         kthread_exit();
  806 }
  807 
  808 static int
  809 icl_soupcall_receive(struct socket *so, void *arg, int waitflag)
  810 {
  811         struct icl_soft_conn *isc;
  812 
  813         if (!soreadable(so))
  814                 return (SU_OK);
  815 
  816         isc = arg;
  817         cv_signal(&isc->receive_cv);
  818         return (SU_OK);
  819 }
  820 
  821 static int
  822 icl_pdu_finalize(struct icl_pdu *request)
  823 {
  824         size_t padding, pdu_len;
  825         uint32_t digest, zero = 0;
  826         int ok;
  827         struct icl_conn *ic;
  828 
  829         ic = request->ip_conn;
  830 
  831         icl_pdu_set_data_segment_length(request, request->ip_data_len);
  832 
  833         pdu_len = icl_pdu_size(request);
  834 
  835         if (ic->ic_header_crc32c) {
  836                 digest = icl_mbuf_to_crc32c(request->ip_bhs_mbuf,
  837                     ISCSI_BHS_SIZE);
  838                 ok = m_append(request->ip_bhs_mbuf, sizeof(digest),
  839                     (void *)&digest);
  840                 if (ok != 1) {
  841                         ICL_WARN("failed to append header digest");
  842                         return (1);
  843                 }
  844         }
  845 
  846         if (request->ip_data_len != 0) {
  847                 padding = icl_pdu_padding(request);
  848                 if (padding > 0) {
  849                         ok = m_append(request->ip_data_mbuf, padding,
  850                             (void *)&zero);
  851                         if (ok != 1) {
  852                                 ICL_WARN("failed to append padding");
  853                                 return (1);
  854                         }
  855                 }
  856 
  857                 if (ic->ic_data_crc32c) {
  858                         digest = icl_mbuf_to_crc32c(request->ip_data_mbuf,
  859                             roundup2(request->ip_data_len, 4));
  860 
  861                         ok = m_append(request->ip_data_mbuf, sizeof(digest),
  862                             (void *)&digest);
  863                         if (ok != 1) {
  864                                 ICL_WARN("failed to append data digest");
  865                                 return (1);
  866                         }
  867                 }
  868 
  869                 m_cat(request->ip_bhs_mbuf, request->ip_data_mbuf);
  870                 request->ip_data_mbuf = NULL;
  871         }
  872 
  873         request->ip_bhs_mbuf->m_pkthdr.len = pdu_len;
  874 
  875         return (0);
  876 }
  877 
  878 static void
  879 icl_conn_send_pdus(struct icl_soft_conn *isc, struct icl_pdu_stailq *queue)
  880 {
  881         struct icl_conn *ic = &isc->ic;
  882         struct icl_pdu *request, *request2;
  883         struct mbuf *m;
  884         struct socket *so;
  885         long available, size, size2;
  886 #ifdef DEBUG_COALESCED
  887         int coalesced;
  888 #endif
  889         int error;
  890 
  891         ICL_CONN_LOCK_ASSERT_NOT(ic);
  892 
  893         so = ic->ic_socket;
  894 
  895         SOCKBUF_LOCK(&so->so_snd);
  896         /*
  897          * Check how much space do we have for transmit.  We can't just
  898          * call sosend() and retry when we get EWOULDBLOCK or EMSGSIZE,
  899          * as it always frees the mbuf chain passed to it, even in case
  900          * of error.
  901          */
  902         available = sbspace(&so->so_snd);
  903         isc->check_send_space = false;
  904 
  905         /*
  906          * Notify the socket upcall that we don't need wakeups
  907          * for the time being.
  908          */
  909         so->so_snd.sb_lowat = so->so_snd.sb_hiwat + 1;
  910         SOCKBUF_UNLOCK(&so->so_snd);
  911 
  912         while (!STAILQ_EMPTY(queue)) {
  913                 request = STAILQ_FIRST(queue);
  914                 size = icl_pdu_size(request);
  915                 if (available < size) {
  916                         /*
  917                          * Set the low watermark, to be checked by
  918                          * sowriteable() in icl_soupcall_send()
  919                          * to avoid unnecessary wakeups until there
  920                          * is enough space for the PDU to fit.
  921                          */
  922                         SOCKBUF_LOCK(&so->so_snd);
  923                         available = sbspace(&so->so_snd);
  924                         if (available < size) {
  925 #if 1
  926                                 ICL_DEBUG("no space to send; "
  927                                     "have %ld, need %ld",
  928                                     available, size);
  929 #endif
  930                                 so->so_snd.sb_lowat = max(size,
  931                                     so->so_snd.sb_hiwat / 8);
  932                                 SOCKBUF_UNLOCK(&so->so_snd);
  933                                 return;
  934                         }
  935                         SOCKBUF_UNLOCK(&so->so_snd);
  936                 }
  937                 STAILQ_REMOVE_HEAD(queue, ip_next);
  938                 error = icl_pdu_finalize(request);
  939                 if (error != 0) {
  940                         ICL_DEBUG("failed to finalize PDU; "
  941                             "dropping connection");
  942                         icl_soft_pdu_done(request, EIO);
  943                         icl_conn_fail(ic);
  944                         return;
  945                 }
  946                 if (coalesce) {
  947                         m = request->ip_bhs_mbuf;
  948                         for (
  949 #ifdef DEBUG_COALESCED
  950                             coalesced = 1
  951 #endif
  952                             ; ;
  953 #ifdef DEBUG_COALESCED
  954                             coalesced++
  955 #endif
  956                             ) {
  957                                 request2 = STAILQ_FIRST(queue);
  958                                 if (request2 == NULL)
  959                                         break;
  960                                 size2 = icl_pdu_size(request2);
  961                                 if (available < size + size2)
  962                                         break;
  963                                 STAILQ_REMOVE_HEAD(queue, ip_next);
  964                                 error = icl_pdu_finalize(request2);
  965                                 if (error != 0) {
  966                                         ICL_DEBUG("failed to finalize PDU; "
  967                                             "dropping connection");
  968                                         icl_soft_pdu_done(request, EIO);
  969                                         icl_soft_pdu_done(request2, EIO);
  970                                         icl_conn_fail(ic);
  971                                         return;
  972                                 }
  973                                 while (m->m_next)
  974                                         m = m->m_next;
  975                                 m_cat(m, request2->ip_bhs_mbuf);
  976                                 request2->ip_bhs_mbuf = NULL;
  977                                 request->ip_bhs_mbuf->m_pkthdr.len += size2;
  978                                 size += size2;
  979                                 icl_soft_pdu_done(request2, 0);
  980                         }
  981 #ifdef DEBUG_COALESCED
  982                         if (coalesced > 1) {
  983                                 ICL_DEBUG("coalesced %d PDUs into %ld bytes",
  984                                     coalesced, size);
  985                         }
  986 #endif
  987                 }
  988                 available -= size;
  989                 error = sosend(so, NULL, NULL, request->ip_bhs_mbuf,
  990                     NULL, MSG_DONTWAIT, curthread);
  991                 request->ip_bhs_mbuf = NULL; /* Sosend consumes the mbuf. */
  992                 if (error != 0) {
  993                         ICL_DEBUG("failed to send PDU, error %d; "
  994                             "dropping connection", error);
  995                         icl_soft_pdu_done(request, error);
  996                         icl_conn_fail(ic);
  997                         return;
  998                 }
  999                 icl_soft_pdu_done(request, 0);
 1000         }
 1001 }
 1002 
 1003 static void
 1004 icl_send_thread(void *arg)
 1005 {
 1006         struct icl_soft_conn *isc;
 1007         struct icl_conn *ic;
 1008         struct icl_pdu_stailq queue;
 1009 
 1010         isc = arg;
 1011         ic = &isc->ic;
 1012 
 1013         STAILQ_INIT(&queue);
 1014 
 1015         ICL_CONN_LOCK(ic);
 1016         for (;;) {
 1017                 for (;;) {
 1018                         /*
 1019                          * Populate the local queue from the main one.
 1020                          * This way the icl_conn_send_pdus() can go through
 1021                          * all the queued PDUs without holding any locks.
 1022                          */
 1023                         if (STAILQ_EMPTY(&queue) || isc->check_send_space)
 1024                                 STAILQ_CONCAT(&queue, &isc->to_send);
 1025 
 1026                         ICL_CONN_UNLOCK(ic);
 1027                         icl_conn_send_pdus(isc, &queue);
 1028                         ICL_CONN_LOCK(ic);
 1029 
 1030                         /*
 1031                          * The icl_soupcall_send() was called since the last
 1032                          * call to sbspace(); go around;
 1033                          */
 1034                         if (isc->check_send_space)
 1035                                 continue;
 1036 
 1037                         /*
 1038                          * Local queue is empty, but we still have PDUs
 1039                          * in the main one; go around.
 1040                          */
 1041                         if (STAILQ_EMPTY(&queue) &&
 1042                             !STAILQ_EMPTY(&isc->to_send))
 1043                                 continue;
 1044 
 1045                         /*
 1046                          * There might be some stuff in the local queue,
 1047                          * which didn't get sent due to not having enough send
 1048                          * space.  Wait for socket upcall.
 1049                          */
 1050                         break;
 1051                 }
 1052 
 1053                 if (ic->ic_disconnecting) {
 1054                         //ICL_DEBUG("terminating");
 1055                         break;
 1056                 }
 1057 
 1058                 cv_wait(&isc->send_cv, ic->ic_lock);
 1059         }
 1060 
 1061         /*
 1062          * We're exiting; move PDUs back to the main queue, so they can
 1063          * get freed properly.  At this point ordering doesn't matter.
 1064          */
 1065         STAILQ_CONCAT(&isc->to_send, &queue);
 1066 
 1067         isc->send_running = false;
 1068         cv_signal(&isc->send_cv);
 1069         ICL_CONN_UNLOCK(ic);
 1070         kthread_exit();
 1071 }
 1072 
 1073 static int
 1074 icl_soupcall_send(struct socket *so, void *arg, int waitflag)
 1075 {
 1076         struct icl_soft_conn *isc;
 1077         struct icl_conn *ic;
 1078 
 1079         if (!sowriteable(so))
 1080                 return (SU_OK);
 1081 
 1082         isc = arg;
 1083         ic = &isc->ic;
 1084 
 1085         ICL_CONN_LOCK(ic);
 1086         isc->check_send_space = true;
 1087         ICL_CONN_UNLOCK(ic);
 1088 
 1089         cv_signal(&isc->send_cv);
 1090 
 1091         return (SU_OK);
 1092 }
 1093 
 1094 static void
 1095 icl_soft_free_mext_pg(struct mbuf *m)
 1096 {
 1097         struct icl_soft_pdu *isp;
 1098 
 1099         M_ASSERTEXTPG(m);
 1100 
 1101         /*
 1102          * Nothing to do for the pages; they are owned by the PDU /
 1103          * I/O request.
 1104          */
 1105 
 1106         /* Drop reference on the PDU. */
 1107         isp = m->m_ext.ext_arg1;
 1108         if (atomic_fetchadd_int(&isp->ref_cnt, -1) == 1)
 1109                 icl_soft_pdu_call_cb(&isp->ip);
 1110 }
 1111 
 1112 static int
 1113 icl_soft_conn_pdu_append_bio(struct icl_conn *ic, struct icl_pdu *request,
 1114     struct bio *bp, size_t offset, size_t len, int flags)
 1115 {
 1116         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)request;
 1117         struct mbuf *m, *m_tail;
 1118         vm_offset_t vaddr;
 1119         size_t mtodo, page_offset, todo;
 1120         int i;
 1121 
 1122         KASSERT(len > 0, ("len == 0"));
 1123 
 1124         m_tail = request->ip_data_mbuf;
 1125         if (m_tail != NULL)
 1126                 for (; m_tail->m_next != NULL; m_tail = m_tail->m_next)
 1127                         ;
 1128 
 1129         MPASS(bp->bio_flags & BIO_UNMAPPED);
 1130         if (offset < PAGE_SIZE - bp->bio_ma_offset) {
 1131                 page_offset = bp->bio_ma_offset + offset;
 1132                 i = 0;
 1133         } else {
 1134                 offset -= PAGE_SIZE - bp->bio_ma_offset;
 1135                 for (i = 1; offset >= PAGE_SIZE; i++)
 1136                         offset -= PAGE_SIZE;
 1137                 page_offset = offset;
 1138         }
 1139 
 1140         if (flags & ICL_NOCOPY) {
 1141                 m = NULL;
 1142                 while (len > 0) {
 1143                         if (m == NULL) {
 1144                                 m = mb_alloc_ext_pgs(flags & ~ICL_NOCOPY,
 1145                                     icl_soft_free_mext_pg);
 1146                                 if (__predict_false(m == NULL))
 1147                                         return (ENOMEM);
 1148                                 atomic_add_int(&isp->ref_cnt, 1);
 1149                                 m->m_ext.ext_arg1 = isp;
 1150                                 m->m_epg_1st_off = page_offset;
 1151                         }
 1152 
 1153                         todo = MIN(len, PAGE_SIZE - page_offset);
 1154 
 1155                         m->m_epg_pa[m->m_epg_npgs] =
 1156                             VM_PAGE_TO_PHYS(bp->bio_ma[i]);
 1157                         m->m_epg_npgs++;
 1158                         m->m_epg_last_len = todo;
 1159                         m->m_len += todo;
 1160                         m->m_ext.ext_size += PAGE_SIZE;
 1161                         MBUF_EXT_PGS_ASSERT_SANITY(m);
 1162 
 1163                         if (m->m_epg_npgs == MBUF_PEXT_MAX_PGS) {
 1164                                 if (m_tail != NULL)
 1165                                         m_tail->m_next = m;
 1166                                 else
 1167                                         request->ip_data_mbuf = m;
 1168                                 m_tail = m;
 1169                                 request->ip_data_len += m->m_len;
 1170                                 m = NULL;
 1171                         }
 1172 
 1173                         page_offset = 0;
 1174                         len -= todo;
 1175                         i++;
 1176                 }
 1177 
 1178                 if (m != NULL) {
 1179                         if (m_tail != NULL)
 1180                                 m_tail->m_next = m;
 1181                         else
 1182                                 request->ip_data_mbuf = m;
 1183                         request->ip_data_len += m->m_len;
 1184                 }
 1185                 return (0);
 1186         }
 1187 
 1188         m = m_getm2(NULL, len, flags, MT_DATA, 0);
 1189         if (__predict_false(m == NULL))
 1190                 return (ENOMEM);
 1191 
 1192         if (request->ip_data_mbuf == NULL) {
 1193                 request->ip_data_mbuf = m;
 1194                 request->ip_data_len = len;
 1195         } else {
 1196                 m_tail->m_next = m;
 1197                 request->ip_data_len += len;
 1198         }
 1199 
 1200         while (len > 0) {
 1201                 todo = MIN(len, PAGE_SIZE - page_offset);
 1202                 vaddr = PHYS_TO_DMAP(VM_PAGE_TO_PHYS(bp->bio_ma[i]));
 1203 
 1204                 do {
 1205                         mtodo = min(todo, M_SIZE(m) - m->m_len);
 1206                         memcpy(mtod(m, char *) + m->m_len, (char *)vaddr +
 1207                             page_offset, mtodo);
 1208                         m->m_len += mtodo;
 1209                         if (m->m_len == M_SIZE(m))
 1210                                 m = m->m_next;
 1211                         page_offset += mtodo;
 1212                         todo -= mtodo;
 1213                 } while (todo > 0);
 1214 
 1215                 page_offset = 0;
 1216                 len -= todo;
 1217                 i++;
 1218         }
 1219 
 1220         return (0);
 1221 }
 1222 
 1223 static int
 1224 icl_soft_conn_pdu_append_data(struct icl_conn *ic, struct icl_pdu *request,
 1225     const void *addr, size_t len, int flags)
 1226 {
 1227         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)request;
 1228         struct mbuf *mb, *newmb;
 1229         size_t copylen, off = 0;
 1230 
 1231         KASSERT(len > 0, ("len == 0"));
 1232 
 1233         if (flags & ICL_NOCOPY) {
 1234                 newmb = m_get(flags & ~ICL_NOCOPY, MT_DATA);
 1235                 if (newmb == NULL) {
 1236                         ICL_WARN("failed to allocate mbuf");
 1237                         return (ENOMEM);
 1238                 }
 1239 
 1240                 newmb->m_flags |= M_RDONLY;
 1241                 m_extaddref(newmb, __DECONST(char *, addr), len, &isp->ref_cnt,
 1242                     icl_soft_mbuf_done, isp, NULL);
 1243                 newmb->m_len = len;
 1244         } else {
 1245                 newmb = m_getm2(NULL, len, flags, MT_DATA, 0);
 1246                 if (newmb == NULL) {
 1247                         ICL_WARN("failed to allocate mbuf for %zd bytes", len);
 1248                         return (ENOMEM);
 1249                 }
 1250 
 1251                 for (mb = newmb; mb != NULL; mb = mb->m_next) {
 1252                         copylen = min(M_TRAILINGSPACE(mb), len - off);
 1253                         memcpy(mtod(mb, char *), (const char *)addr + off, copylen);
 1254                         mb->m_len = copylen;
 1255                         off += copylen;
 1256                 }
 1257                 KASSERT(off == len, ("%s: off != len", __func__));
 1258         }
 1259 
 1260         if (request->ip_data_mbuf == NULL) {
 1261                 request->ip_data_mbuf = newmb;
 1262                 request->ip_data_len = len;
 1263         } else {
 1264                 m_cat(request->ip_data_mbuf, newmb);
 1265                 request->ip_data_len += len;
 1266         }
 1267 
 1268         return (0);
 1269 }
 1270 
 1271 void
 1272 icl_soft_conn_pdu_get_bio(struct icl_conn *ic, struct icl_pdu *ip,
 1273     size_t pdu_off, struct bio *bp, size_t bio_off, size_t len)
 1274 {
 1275         vm_offset_t vaddr;
 1276         size_t page_offset, todo;
 1277         int i __unused;
 1278 
 1279         MPASS(bp->bio_flags & BIO_UNMAPPED);
 1280         if (bio_off < PAGE_SIZE - bp->bio_ma_offset) {
 1281                 page_offset = bp->bio_ma_offset + bio_off;
 1282                 i = 0;
 1283         } else {
 1284                 bio_off -= PAGE_SIZE - bp->bio_ma_offset;
 1285                 for (i = 1; bio_off >= PAGE_SIZE; i++)
 1286                         bio_off -= PAGE_SIZE;
 1287                 page_offset = bio_off;
 1288         }
 1289 
 1290         while (len > 0) {
 1291                 todo = MIN(len, PAGE_SIZE - page_offset);
 1292 
 1293                 vaddr = PHYS_TO_DMAP(VM_PAGE_TO_PHYS(bp->bio_ma[i]));
 1294                 m_copydata(ip->ip_data_mbuf, pdu_off, todo, (char *)vaddr +
 1295                     page_offset);
 1296 
 1297                 page_offset = 0;
 1298                 pdu_off += todo;
 1299                 len -= todo;
 1300                 i++;
 1301         }
 1302 }
 1303 
 1304 void
 1305 icl_soft_conn_pdu_get_data(struct icl_conn *ic, struct icl_pdu *ip,
 1306     size_t off, void *addr, size_t len)
 1307 {
 1308 
 1309         m_copydata(ip->ip_data_mbuf, off, len, addr);
 1310 }
 1311 
 1312 static void
 1313 icl_soft_conn_pdu_queue(struct icl_conn *ic, struct icl_pdu *ip)
 1314 {
 1315 
 1316         icl_soft_conn_pdu_queue_cb(ic, ip, NULL);
 1317 }
 1318 
 1319 static void
 1320 icl_soft_conn_pdu_queue_cb(struct icl_conn *ic, struct icl_pdu *ip,
 1321     icl_pdu_cb cb)
 1322 {
 1323         struct icl_soft_conn *isc = (struct icl_soft_conn *)ic;
 1324         struct icl_soft_pdu *isp = (struct icl_soft_pdu *)ip;
 1325 
 1326         ICL_CONN_LOCK_ASSERT(ic);
 1327         isp->ref_cnt++;
 1328         isp->cb = cb;
 1329 
 1330         if (ic->ic_disconnecting || ic->ic_socket == NULL) {
 1331                 ICL_DEBUG("icl_pdu_queue on closed connection");
 1332                 icl_soft_pdu_done(ip, ENOTCONN);
 1333                 return;
 1334         }
 1335 
 1336         if (!STAILQ_EMPTY(&isc->to_send)) {
 1337                 STAILQ_INSERT_TAIL(&isc->to_send, ip, ip_next);
 1338                 /*
 1339                  * If the queue is not empty, someone else had already
 1340                  * signaled the send thread; no need to do that again,
 1341                  * just return.
 1342                  */
 1343                 return;
 1344         }
 1345 
 1346         STAILQ_INSERT_TAIL(&isc->to_send, ip, ip_next);
 1347         cv_signal(&isc->send_cv);
 1348 }
 1349 
 1350 static struct icl_conn *
 1351 icl_soft_new_conn(const char *name, struct mtx *lock)
 1352 {
 1353         struct icl_soft_conn *isc;
 1354         struct icl_conn *ic;
 1355 
 1356         refcount_acquire(&icl_ncons);
 1357 
 1358         isc = (struct icl_soft_conn *)kobj_create(&icl_soft_class, M_ICL_SOFT,
 1359             M_WAITOK | M_ZERO);
 1360 
 1361         STAILQ_INIT(&isc->to_send);
 1362         cv_init(&isc->send_cv, "icl_tx");
 1363         cv_init(&isc->receive_cv, "icl_rx");
 1364 
 1365         ic = &isc->ic;
 1366         ic->ic_lock = lock;
 1367 #ifdef DIAGNOSTIC
 1368         refcount_init(&ic->ic_outstanding_pdus, 0);
 1369 #endif
 1370         ic->ic_name = name;
 1371         ic->ic_offload = "None";
 1372         ic->ic_unmapped = PMAP_HAS_DMAP;
 1373 
 1374         return (ic);
 1375 }
 1376 
 1377 void
 1378 icl_soft_conn_free(struct icl_conn *ic)
 1379 {
 1380         struct icl_soft_conn *isc = (struct icl_soft_conn *)ic;
 1381 
 1382 #ifdef DIAGNOSTIC
 1383         KASSERT(ic->ic_outstanding_pdus == 0,
 1384             ("destroying session with %d outstanding PDUs",
 1385              ic->ic_outstanding_pdus));
 1386 #endif
 1387         cv_destroy(&isc->send_cv);
 1388         cv_destroy(&isc->receive_cv);
 1389         kobj_delete((struct kobj *)isc, M_ICL_SOFT);
 1390         refcount_release(&icl_ncons);
 1391 }
 1392 
 1393 static int
 1394 icl_conn_start(struct icl_conn *ic)
 1395 {
 1396         struct icl_soft_conn *isc = (struct icl_soft_conn *)ic;
 1397         size_t minspace;
 1398         struct sockopt opt;
 1399         int error, one = 1;
 1400 
 1401         ICL_CONN_LOCK(ic);
 1402 
 1403         /*
 1404          * XXX: Ugly hack.
 1405          */
 1406         if (ic->ic_socket == NULL) {
 1407                 ICL_CONN_UNLOCK(ic);
 1408                 return (EINVAL);
 1409         }
 1410 
 1411         isc->receive_state = ICL_CONN_STATE_BHS;
 1412         isc->receive_len = sizeof(struct iscsi_bhs);
 1413         ic->ic_disconnecting = false;
 1414 
 1415         ICL_CONN_UNLOCK(ic);
 1416 
 1417         /*
 1418          * For sendspace, this is required because the current code cannot
 1419          * send a PDU in pieces; thus, the minimum buffer size is equal
 1420          * to the maximum PDU size.  "+4" is to account for possible padding.
 1421          */
 1422         minspace = sizeof(struct iscsi_bhs) +
 1423             ic->ic_max_send_data_segment_length +
 1424             ISCSI_HEADER_DIGEST_SIZE + ISCSI_DATA_DIGEST_SIZE + 4;
 1425         if (sendspace < minspace) {
 1426                 ICL_WARN("kern.icl.sendspace too low; must be at least %zd",
 1427                     minspace);
 1428                 sendspace = minspace;
 1429         }
 1430         minspace = sizeof(struct iscsi_bhs) +
 1431             ic->ic_max_recv_data_segment_length +
 1432             ISCSI_HEADER_DIGEST_SIZE + ISCSI_DATA_DIGEST_SIZE + 4;
 1433         if (recvspace < minspace) {
 1434                 ICL_WARN("kern.icl.recvspace too low; must be at least %zd",
 1435                     minspace);
 1436                 recvspace = minspace;
 1437         }
 1438 
 1439         error = soreserve(ic->ic_socket, sendspace, recvspace);
 1440         if (error != 0) {
 1441                 ICL_WARN("soreserve failed with error %d", error);
 1442                 icl_soft_conn_close(ic);
 1443                 return (error);
 1444         }
 1445         ic->ic_socket->so_snd.sb_flags |= SB_AUTOSIZE;
 1446         ic->ic_socket->so_rcv.sb_flags |= SB_AUTOSIZE;
 1447 
 1448         /*
 1449          * Disable Nagle.
 1450          */
 1451         bzero(&opt, sizeof(opt));
 1452         opt.sopt_dir = SOPT_SET;
 1453         opt.sopt_level = IPPROTO_TCP;
 1454         opt.sopt_name = TCP_NODELAY;
 1455         opt.sopt_val = &one;
 1456         opt.sopt_valsize = sizeof(one);
 1457         error = sosetopt(ic->ic_socket, &opt);
 1458         if (error != 0) {
 1459                 ICL_WARN("disabling TCP_NODELAY failed with error %d", error);
 1460                 icl_soft_conn_close(ic);
 1461                 return (error);
 1462         }
 1463 
 1464         /*
 1465          * Register socket upcall, to get notified about incoming PDUs
 1466          * and free space to send outgoing ones.
 1467          */
 1468         SOCKBUF_LOCK(&ic->ic_socket->so_snd);
 1469         soupcall_set(ic->ic_socket, SO_SND, icl_soupcall_send, isc);
 1470         SOCKBUF_UNLOCK(&ic->ic_socket->so_snd);
 1471         SOCKBUF_LOCK(&ic->ic_socket->so_rcv);
 1472         soupcall_set(ic->ic_socket, SO_RCV, icl_soupcall_receive, isc);
 1473         SOCKBUF_UNLOCK(&ic->ic_socket->so_rcv);
 1474 
 1475         /*
 1476          * Start threads.
 1477          */
 1478         ICL_CONN_LOCK(ic);
 1479         isc->send_running = isc->receive_running = true;
 1480         ICL_CONN_UNLOCK(ic);
 1481         error = kthread_add(icl_send_thread, ic, NULL, NULL, 0, 0, "%stx",
 1482             ic->ic_name);
 1483         if (error != 0) {
 1484                 ICL_WARN("kthread_add(9) failed with error %d", error);
 1485                 ICL_CONN_LOCK(ic);
 1486                 isc->send_running = isc->receive_running = false;
 1487                 cv_signal(&isc->send_cv);
 1488                 ICL_CONN_UNLOCK(ic);
 1489                 icl_soft_conn_close(ic);
 1490                 return (error);
 1491         }
 1492         error = kthread_add(icl_receive_thread, ic, NULL, NULL, 0, 0, "%srx",
 1493             ic->ic_name);
 1494         if (error != 0) {
 1495                 ICL_WARN("kthread_add(9) failed with error %d", error);
 1496                 ICL_CONN_LOCK(ic);
 1497                 isc->receive_running = false;
 1498                 cv_signal(&isc->send_cv);
 1499                 ICL_CONN_UNLOCK(ic);
 1500                 icl_soft_conn_close(ic);
 1501                 return (error);
 1502         }
 1503 
 1504         return (0);
 1505 }
 1506 
 1507 int
 1508 icl_soft_conn_handoff(struct icl_conn *ic, int fd)
 1509 {
 1510         struct file *fp;
 1511         struct socket *so;
 1512         cap_rights_t rights;
 1513         int error;
 1514 
 1515         ICL_CONN_LOCK_ASSERT_NOT(ic);
 1516 
 1517 #ifdef ICL_KERNEL_PROXY
 1518         /*
 1519          * We're transitioning to Full Feature phase, and we don't
 1520          * really care.
 1521          */
 1522         if (fd == 0) {
 1523                 ICL_CONN_LOCK(ic);
 1524                 if (ic->ic_socket == NULL) {
 1525                         ICL_CONN_UNLOCK(ic);
 1526                         ICL_WARN("proxy handoff without connect"); 
 1527                         return (EINVAL);
 1528                 }
 1529                 ICL_CONN_UNLOCK(ic);
 1530                 return (0);
 1531         }
 1532 #endif
 1533 
 1534         /*
 1535          * Steal the socket from userland.
 1536          */
 1537         error = fget(curthread, fd,
 1538             cap_rights_init_one(&rights, CAP_SOCK_CLIENT), &fp);
 1539         if (error != 0)
 1540                 return (error);
 1541         if (fp->f_type != DTYPE_SOCKET) {
 1542                 fdrop(fp, curthread);
 1543                 return (EINVAL);
 1544         }
 1545         so = fp->f_data;
 1546         if (so->so_type != SOCK_STREAM) {
 1547                 fdrop(fp, curthread);
 1548                 return (EINVAL);
 1549         }
 1550 
 1551         ICL_CONN_LOCK(ic);
 1552 
 1553         if (ic->ic_socket != NULL) {
 1554                 ICL_CONN_UNLOCK(ic);
 1555                 fdrop(fp, curthread);
 1556                 return (EBUSY);
 1557         }
 1558 
 1559         ic->ic_socket = fp->f_data;
 1560         fp->f_ops = &badfileops;
 1561         fp->f_data = NULL;
 1562         fdrop(fp, curthread);
 1563         ICL_CONN_UNLOCK(ic);
 1564 
 1565         error = icl_conn_start(ic);
 1566 
 1567         return (error);
 1568 }
 1569 
 1570 void
 1571 icl_soft_conn_close(struct icl_conn *ic)
 1572 {
 1573         struct icl_soft_conn *isc = (struct icl_soft_conn *)ic;
 1574         struct icl_pdu *pdu;
 1575         struct socket *so;
 1576 
 1577         /*
 1578          * Wake up the threads, so they can properly terminate.
 1579          * Receive thread sleeps on so->so_rcv lock, send on ic->ic_lock.
 1580          */
 1581         ICL_CONN_LOCK(ic);
 1582         if (!ic->ic_disconnecting) {
 1583                 so = ic->ic_socket;
 1584                 if (so)
 1585                         SOCKBUF_LOCK(&so->so_rcv);
 1586                 ic->ic_disconnecting = true;
 1587                 if (so)
 1588                         SOCKBUF_UNLOCK(&so->so_rcv);
 1589         }
 1590         while (isc->receive_running || isc->send_running) {
 1591                 cv_signal(&isc->receive_cv);
 1592                 cv_signal(&isc->send_cv);
 1593                 cv_wait(&isc->send_cv, ic->ic_lock);
 1594         }
 1595 
 1596         /* Some other thread could close the connection same time. */
 1597         so = ic->ic_socket;
 1598         if (so == NULL) {
 1599                 ICL_CONN_UNLOCK(ic);
 1600                 return;
 1601         }
 1602         ic->ic_socket = NULL;
 1603 
 1604         /*
 1605          * Deregister socket upcalls.
 1606          */
 1607         ICL_CONN_UNLOCK(ic);
 1608         SOCKBUF_LOCK(&so->so_snd);
 1609         if (so->so_snd.sb_upcall != NULL)
 1610                 soupcall_clear(so, SO_SND);
 1611         SOCKBUF_UNLOCK(&so->so_snd);
 1612         SOCKBUF_LOCK(&so->so_rcv);
 1613         if (so->so_rcv.sb_upcall != NULL)
 1614                 soupcall_clear(so, SO_RCV);
 1615         SOCKBUF_UNLOCK(&so->so_rcv);
 1616         soclose(so);
 1617         ICL_CONN_LOCK(ic);
 1618 
 1619         if (isc->receive_pdu != NULL) {
 1620                 //ICL_DEBUG("freeing partially received PDU");
 1621                 icl_soft_conn_pdu_free(ic, isc->receive_pdu);
 1622                 isc->receive_pdu = NULL;
 1623         }
 1624 
 1625         /*
 1626          * Remove any outstanding PDUs from the send queue.
 1627          */
 1628         while (!STAILQ_EMPTY(&isc->to_send)) {
 1629                 pdu = STAILQ_FIRST(&isc->to_send);
 1630                 STAILQ_REMOVE_HEAD(&isc->to_send, ip_next);
 1631                 icl_soft_pdu_done(pdu, ENOTCONN);
 1632         }
 1633 
 1634         KASSERT(STAILQ_EMPTY(&isc->to_send),
 1635             ("destroying session with non-empty send queue"));
 1636         ICL_CONN_UNLOCK(ic);
 1637 }
 1638 
 1639 int
 1640 icl_soft_conn_task_setup(struct icl_conn *ic, struct icl_pdu *ip,
 1641     struct ccb_scsiio *csio, uint32_t *task_tagp, void **prvp)
 1642 {
 1643 
 1644         return (0);
 1645 }
 1646 
 1647 void
 1648 icl_soft_conn_task_done(struct icl_conn *ic, void *prv)
 1649 {
 1650 }
 1651 
 1652 int
 1653 icl_soft_conn_transfer_setup(struct icl_conn *ic, struct icl_pdu *ip,
 1654     union ctl_io *io, uint32_t *transfer_tag, void **prvp)
 1655 {
 1656 
 1657         return (0);
 1658 }
 1659 
 1660 void
 1661 icl_soft_conn_transfer_done(struct icl_conn *ic, void *prv)
 1662 {
 1663 }
 1664 
 1665 static int
 1666 icl_soft_limits(struct icl_drv_limits *idl, int socket)
 1667 {
 1668 
 1669         idl->idl_max_recv_data_segment_length = max_data_segment_length;
 1670         idl->idl_max_send_data_segment_length = max_data_segment_length;
 1671         idl->idl_max_burst_length = max_burst_length;
 1672         idl->idl_first_burst_length = first_burst_length;
 1673 
 1674         return (0);
 1675 }
 1676 
 1677 #ifdef ICL_KERNEL_PROXY
 1678 int
 1679 icl_soft_conn_connect(struct icl_conn *ic, int domain, int socktype,
 1680     int protocol, struct sockaddr *from_sa, struct sockaddr *to_sa)
 1681 {
 1682 
 1683         return (icl_soft_proxy_connect(ic, domain, socktype, protocol,
 1684             from_sa, to_sa));
 1685 }
 1686 
 1687 int
 1688 icl_soft_handoff_sock(struct icl_conn *ic, struct socket *so)
 1689 {
 1690         int error;
 1691 
 1692         ICL_CONN_LOCK_ASSERT_NOT(ic);
 1693 
 1694         if (so->so_type != SOCK_STREAM)
 1695                 return (EINVAL);
 1696 
 1697         ICL_CONN_LOCK(ic);
 1698         if (ic->ic_socket != NULL) {
 1699                 ICL_CONN_UNLOCK(ic);
 1700                 return (EBUSY);
 1701         }
 1702         ic->ic_socket = so;
 1703         ICL_CONN_UNLOCK(ic);
 1704 
 1705         error = icl_conn_start(ic);
 1706 
 1707         return (error);
 1708 }
 1709 #endif /* ICL_KERNEL_PROXY */
 1710 
 1711 static int
 1712 icl_soft_load(void)
 1713 {
 1714         int error;
 1715 
 1716         icl_soft_pdu_zone = uma_zcreate("icl_soft_pdu",
 1717             sizeof(struct icl_soft_pdu), NULL, NULL, NULL, NULL,
 1718             UMA_ALIGN_PTR, 0);
 1719         refcount_init(&icl_ncons, 0);
 1720 
 1721         /*
 1722          * The reason we call this "none" is that to the user,
 1723          * it's known as "offload driver"; "offload driver: soft"
 1724          * doesn't make much sense.
 1725          */
 1726         error = icl_register("none", false, 0,
 1727             icl_soft_limits, icl_soft_new_conn);
 1728         KASSERT(error == 0, ("failed to register"));
 1729 
 1730 #if defined(ICL_KERNEL_PROXY) && 0
 1731         /*
 1732          * Debugging aid for kernel proxy functionality.
 1733          */
 1734         error = icl_register("proxytest", true, 0,
 1735             icl_soft_limits, icl_soft_new_conn);
 1736         KASSERT(error == 0, ("failed to register"));
 1737 #endif
 1738 
 1739         return (error);
 1740 }
 1741 
 1742 static int
 1743 icl_soft_unload(void)
 1744 {
 1745 
 1746         if (icl_ncons != 0)
 1747                 return (EBUSY);
 1748 
 1749         icl_unregister("none", false);
 1750 #if defined(ICL_KERNEL_PROXY) && 0
 1751         icl_unregister("proxytest", true);
 1752 #endif
 1753 
 1754         uma_zdestroy(icl_soft_pdu_zone);
 1755 
 1756         return (0);
 1757 }
 1758 
 1759 static int
 1760 icl_soft_modevent(module_t mod, int what, void *arg)
 1761 {
 1762 
 1763         switch (what) {
 1764         case MOD_LOAD:
 1765                 return (icl_soft_load());
 1766         case MOD_UNLOAD:
 1767                 return (icl_soft_unload());
 1768         default:
 1769                 return (EINVAL);
 1770         }
 1771 }
 1772 
 1773 moduledata_t icl_soft_data = {
 1774         "icl_soft",
 1775         icl_soft_modevent,
 1776         0
 1777 };
 1778 
 1779 DECLARE_MODULE(icl_soft, icl_soft_data, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
 1780 MODULE_DEPEND(icl_soft, icl, 1, 1, 1);
 1781 MODULE_VERSION(icl_soft, 1);

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