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

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    1 /*      $NetBSD: svc_vc.c,v 1.7 2000/08/03 00:01:53 fvdl Exp $  */
    2 
    3 /*-
    4  * Copyright (c) 2009, Sun Microsystems, Inc.
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without 
    8  * modification, are permitted provided that the following conditions are met:
    9  * - Redistributions of source code must retain the above copyright notice, 
   10  *   this list of conditions and the following disclaimer.
   11  * - Redistributions in binary form must reproduce the above copyright notice, 
   12  *   this list of conditions and the following disclaimer in the documentation 
   13  *   and/or other materials provided with the distribution.
   14  * - Neither the name of Sun Microsystems, Inc. nor the names of its 
   15  *   contributors may be used to endorse or promote products derived 
   16  *   from this software without specific prior written permission.
   17  * 
   18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
   19  * AND 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 COPYRIGHT HOLDER OR CONTRIBUTORS BE 
   22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
   23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
   24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
   25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
   26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
   27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
   28  * POSSIBILITY OF SUCH DAMAGE.
   29  */
   30 
   31 #if defined(LIBC_SCCS) && !defined(lint)
   32 static char *sccsid2 = "@(#)svc_tcp.c 1.21 87/08/11 Copyr 1984 Sun Micro";
   33 static char *sccsid = "@(#)svc_tcp.c    2.2 88/08/01 4.0 RPCSRC";
   34 #endif
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: releng/11.2/sys/rpc/svc_vc.c 331722 2018-03-29 02:50:57Z eadler $");
   37 
   38 /*
   39  * svc_vc.c, Server side for Connection Oriented based RPC. 
   40  *
   41  * Actually implements two flavors of transporter -
   42  * a tcp rendezvouser (a listner and connection establisher)
   43  * and a record/tcp stream.
   44  */
   45 
   46 #include <sys/param.h>
   47 #include <sys/lock.h>
   48 #include <sys/kernel.h>
   49 #include <sys/malloc.h>
   50 #include <sys/mbuf.h>
   51 #include <sys/mutex.h>
   52 #include <sys/proc.h>
   53 #include <sys/protosw.h>
   54 #include <sys/queue.h>
   55 #include <sys/socket.h>
   56 #include <sys/socketvar.h>
   57 #include <sys/sx.h>
   58 #include <sys/systm.h>
   59 #include <sys/uio.h>
   60 
   61 #include <net/vnet.h>
   62 
   63 #include <netinet/tcp.h>
   64 
   65 #include <rpc/rpc.h>
   66 
   67 #include <rpc/krpc.h>
   68 #include <rpc/rpc_com.h>
   69 
   70 #include <security/mac/mac_framework.h>
   71 
   72 static bool_t svc_vc_rendezvous_recv(SVCXPRT *, struct rpc_msg *,
   73     struct sockaddr **, struct mbuf **);
   74 static enum xprt_stat svc_vc_rendezvous_stat(SVCXPRT *);
   75 static void svc_vc_rendezvous_destroy(SVCXPRT *);
   76 static bool_t svc_vc_null(void);
   77 static void svc_vc_destroy(SVCXPRT *);
   78 static enum xprt_stat svc_vc_stat(SVCXPRT *);
   79 static bool_t svc_vc_ack(SVCXPRT *, uint32_t *);
   80 static bool_t svc_vc_recv(SVCXPRT *, struct rpc_msg *,
   81     struct sockaddr **, struct mbuf **);
   82 static bool_t svc_vc_reply(SVCXPRT *, struct rpc_msg *,
   83     struct sockaddr *, struct mbuf *, uint32_t *seq);
   84 static bool_t svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in);
   85 static bool_t svc_vc_rendezvous_control (SVCXPRT *xprt, const u_int rq,
   86     void *in);
   87 static void svc_vc_backchannel_destroy(SVCXPRT *);
   88 static enum xprt_stat svc_vc_backchannel_stat(SVCXPRT *);
   89 static bool_t svc_vc_backchannel_recv(SVCXPRT *, struct rpc_msg *,
   90     struct sockaddr **, struct mbuf **);
   91 static bool_t svc_vc_backchannel_reply(SVCXPRT *, struct rpc_msg *,
   92     struct sockaddr *, struct mbuf *, uint32_t *);
   93 static bool_t svc_vc_backchannel_control(SVCXPRT *xprt, const u_int rq,
   94     void *in);
   95 static SVCXPRT *svc_vc_create_conn(SVCPOOL *pool, struct socket *so,
   96     struct sockaddr *raddr);
   97 static int svc_vc_accept(struct socket *head, struct socket **sop);
   98 static int svc_vc_soupcall(struct socket *so, void *arg, int waitflag);
   99 
  100 static struct xp_ops svc_vc_rendezvous_ops = {
  101         .xp_recv =      svc_vc_rendezvous_recv,
  102         .xp_stat =      svc_vc_rendezvous_stat,
  103         .xp_reply =     (bool_t (*)(SVCXPRT *, struct rpc_msg *,
  104                 struct sockaddr *, struct mbuf *, uint32_t *))svc_vc_null,
  105         .xp_destroy =   svc_vc_rendezvous_destroy,
  106         .xp_control =   svc_vc_rendezvous_control
  107 };
  108 
  109 static struct xp_ops svc_vc_ops = {
  110         .xp_recv =      svc_vc_recv,
  111         .xp_stat =      svc_vc_stat,
  112         .xp_ack =       svc_vc_ack,
  113         .xp_reply =     svc_vc_reply,
  114         .xp_destroy =   svc_vc_destroy,
  115         .xp_control =   svc_vc_control
  116 };
  117 
  118 static struct xp_ops svc_vc_backchannel_ops = {
  119         .xp_recv =      svc_vc_backchannel_recv,
  120         .xp_stat =      svc_vc_backchannel_stat,
  121         .xp_reply =     svc_vc_backchannel_reply,
  122         .xp_destroy =   svc_vc_backchannel_destroy,
  123         .xp_control =   svc_vc_backchannel_control
  124 };
  125 
  126 /*
  127  * Usage:
  128  *      xprt = svc_vc_create(sock, send_buf_size, recv_buf_size);
  129  *
  130  * Creates, registers, and returns a (rpc) tcp based transporter.
  131  * Once *xprt is initialized, it is registered as a transporter
  132  * see (svc.h, xprt_register).  This routine returns
  133  * a NULL if a problem occurred.
  134  *
  135  * The filedescriptor passed in is expected to refer to a bound, but
  136  * not yet connected socket.
  137  *
  138  * Since streams do buffered io similar to stdio, the caller can specify
  139  * how big the send and receive buffers are via the second and third parms;
  140  * 0 => use the system default.
  141  */
  142 SVCXPRT *
  143 svc_vc_create(SVCPOOL *pool, struct socket *so, size_t sendsize,
  144     size_t recvsize)
  145 {
  146         SVCXPRT *xprt;
  147         struct sockaddr* sa;
  148         int error;
  149 
  150         SOCK_LOCK(so);
  151         if (so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED)) {
  152                 SOCK_UNLOCK(so);
  153                 CURVNET_SET(so->so_vnet);
  154                 error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
  155                 CURVNET_RESTORE();
  156                 if (error)
  157                         return (NULL);
  158                 xprt = svc_vc_create_conn(pool, so, sa);
  159                 free(sa, M_SONAME);
  160                 return (xprt);
  161         }
  162         SOCK_UNLOCK(so);
  163 
  164         xprt = svc_xprt_alloc();
  165         sx_init(&xprt->xp_lock, "xprt->xp_lock");
  166         xprt->xp_pool = pool;
  167         xprt->xp_socket = so;
  168         xprt->xp_p1 = NULL;
  169         xprt->xp_p2 = NULL;
  170         xprt->xp_ops = &svc_vc_rendezvous_ops;
  171 
  172         CURVNET_SET(so->so_vnet);
  173         error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
  174         CURVNET_RESTORE();
  175         if (error) {
  176                 goto cleanup_svc_vc_create;
  177         }
  178 
  179         memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
  180         free(sa, M_SONAME);
  181 
  182         xprt_register(xprt);
  183 
  184         solisten(so, -1, curthread);
  185 
  186         SOCKBUF_LOCK(&so->so_rcv);
  187         xprt->xp_upcallset = 1;
  188         soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
  189         SOCKBUF_UNLOCK(&so->so_rcv);
  190 
  191         return (xprt);
  192 
  193 cleanup_svc_vc_create:
  194         sx_destroy(&xprt->xp_lock);
  195         svc_xprt_free(xprt);
  196 
  197         return (NULL);
  198 }
  199 
  200 /*
  201  * Create a new transport for a socket optained via soaccept().
  202  */
  203 SVCXPRT *
  204 svc_vc_create_conn(SVCPOOL *pool, struct socket *so, struct sockaddr *raddr)
  205 {
  206         SVCXPRT *xprt;
  207         struct cf_conn *cd;
  208         struct sockaddr* sa = NULL;
  209         struct sockopt opt;
  210         int one = 1;
  211         int error;
  212 
  213         bzero(&opt, sizeof(struct sockopt));
  214         opt.sopt_dir = SOPT_SET;
  215         opt.sopt_level = SOL_SOCKET;
  216         opt.sopt_name = SO_KEEPALIVE;
  217         opt.sopt_val = &one;
  218         opt.sopt_valsize = sizeof(one);
  219         error = sosetopt(so, &opt);
  220         if (error) {
  221                 return (NULL);
  222         }
  223 
  224         if (so->so_proto->pr_protocol == IPPROTO_TCP) {
  225                 bzero(&opt, sizeof(struct sockopt));
  226                 opt.sopt_dir = SOPT_SET;
  227                 opt.sopt_level = IPPROTO_TCP;
  228                 opt.sopt_name = TCP_NODELAY;
  229                 opt.sopt_val = &one;
  230                 opt.sopt_valsize = sizeof(one);
  231                 error = sosetopt(so, &opt);
  232                 if (error) {
  233                         return (NULL);
  234                 }
  235         }
  236 
  237         cd = mem_alloc(sizeof(*cd));
  238         cd->strm_stat = XPRT_IDLE;
  239 
  240         xprt = svc_xprt_alloc();
  241         sx_init(&xprt->xp_lock, "xprt->xp_lock");
  242         xprt->xp_pool = pool;
  243         xprt->xp_socket = so;
  244         xprt->xp_p1 = cd;
  245         xprt->xp_p2 = NULL;
  246         xprt->xp_ops = &svc_vc_ops;
  247 
  248         /*
  249          * See http://www.connectathon.org/talks96/nfstcp.pdf - client
  250          * has a 5 minute timer, server has a 6 minute timer.
  251          */
  252         xprt->xp_idletimeout = 6 * 60;
  253 
  254         memcpy(&xprt->xp_rtaddr, raddr, raddr->sa_len);
  255 
  256         CURVNET_SET(so->so_vnet);
  257         error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
  258         CURVNET_RESTORE();
  259         if (error)
  260                 goto cleanup_svc_vc_create;
  261 
  262         memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
  263         free(sa, M_SONAME);
  264 
  265         xprt_register(xprt);
  266 
  267         SOCKBUF_LOCK(&so->so_rcv);
  268         xprt->xp_upcallset = 1;
  269         soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
  270         SOCKBUF_UNLOCK(&so->so_rcv);
  271 
  272         /*
  273          * Throw the transport into the active list in case it already
  274          * has some data buffered.
  275          */
  276         sx_xlock(&xprt->xp_lock);
  277         xprt_active(xprt);
  278         sx_xunlock(&xprt->xp_lock);
  279 
  280         return (xprt);
  281 cleanup_svc_vc_create:
  282         sx_destroy(&xprt->xp_lock);
  283         svc_xprt_free(xprt);
  284         mem_free(cd, sizeof(*cd));
  285 
  286         return (NULL);
  287 }
  288 
  289 /*
  290  * Create a new transport for a backchannel on a clnt_vc socket.
  291  */
  292 SVCXPRT *
  293 svc_vc_create_backchannel(SVCPOOL *pool)
  294 {
  295         SVCXPRT *xprt = NULL;
  296         struct cf_conn *cd = NULL;
  297 
  298         cd = mem_alloc(sizeof(*cd));
  299         cd->strm_stat = XPRT_IDLE;
  300 
  301         xprt = svc_xprt_alloc();
  302         sx_init(&xprt->xp_lock, "xprt->xp_lock");
  303         xprt->xp_pool = pool;
  304         xprt->xp_socket = NULL;
  305         xprt->xp_p1 = cd;
  306         xprt->xp_p2 = NULL;
  307         xprt->xp_ops = &svc_vc_backchannel_ops;
  308         return (xprt);
  309 }
  310 
  311 /*
  312  * This does all of the accept except the final call to soaccept. The
  313  * caller will call soaccept after dropping its locks (soaccept may
  314  * call malloc).
  315  */
  316 int
  317 svc_vc_accept(struct socket *head, struct socket **sop)
  318 {
  319         int error = 0;
  320         struct socket *so;
  321 
  322         if ((head->so_options & SO_ACCEPTCONN) == 0) {
  323                 error = EINVAL;
  324                 goto done;
  325         }
  326 #ifdef MAC
  327         error = mac_socket_check_accept(curthread->td_ucred, head);
  328         if (error != 0)
  329                 goto done;
  330 #endif
  331         ACCEPT_LOCK();
  332         if (TAILQ_EMPTY(&head->so_comp)) {
  333                 ACCEPT_UNLOCK();
  334                 error = EWOULDBLOCK;
  335                 goto done;
  336         }
  337         so = TAILQ_FIRST(&head->so_comp);
  338         KASSERT(!(so->so_qstate & SQ_INCOMP), ("svc_vc_accept: so SQ_INCOMP"));
  339         KASSERT(so->so_qstate & SQ_COMP, ("svc_vc_accept: so not SQ_COMP"));
  340 
  341         /*
  342          * Before changing the flags on the socket, we have to bump the
  343          * reference count.  Otherwise, if the protocol calls sofree(),
  344          * the socket will be released due to a zero refcount.
  345          * XXX might not need soref() since this is simpler than kern_accept.
  346          */
  347         SOCK_LOCK(so);                  /* soref() and so_state update */
  348         soref(so);                      /* file descriptor reference */
  349 
  350         TAILQ_REMOVE(&head->so_comp, so, so_list);
  351         head->so_qlen--;
  352         so->so_state |= (head->so_state & SS_NBIO);
  353         so->so_qstate &= ~SQ_COMP;
  354         so->so_head = NULL;
  355 
  356         SOCK_UNLOCK(so);
  357         ACCEPT_UNLOCK();
  358 
  359         *sop = so;
  360 
  361         /* connection has been removed from the listen queue */
  362         KNOTE_UNLOCKED(&head->so_rcv.sb_sel.si_note, 0);
  363 done:
  364         return (error);
  365 }
  366 
  367 /*ARGSUSED*/
  368 static bool_t
  369 svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg,
  370     struct sockaddr **addrp, struct mbuf **mp)
  371 {
  372         struct socket *so = NULL;
  373         struct sockaddr *sa = NULL;
  374         int error;
  375         SVCXPRT *new_xprt;
  376 
  377         /*
  378          * The socket upcall calls xprt_active() which will eventually
  379          * cause the server to call us here. We attempt to accept a
  380          * connection from the socket and turn it into a new
  381          * transport. If the accept fails, we have drained all pending
  382          * connections so we call xprt_inactive().
  383          */
  384         sx_xlock(&xprt->xp_lock);
  385 
  386         error = svc_vc_accept(xprt->xp_socket, &so);
  387 
  388         if (error == EWOULDBLOCK) {
  389                 /*
  390                  * We must re-test for new connections after taking
  391                  * the lock to protect us in the case where a new
  392                  * connection arrives after our call to accept fails
  393                  * with EWOULDBLOCK.
  394                  */
  395                 ACCEPT_LOCK();
  396                 if (TAILQ_EMPTY(&xprt->xp_socket->so_comp))
  397                         xprt_inactive_self(xprt);
  398                 ACCEPT_UNLOCK();
  399                 sx_xunlock(&xprt->xp_lock);
  400                 return (FALSE);
  401         }
  402 
  403         if (error) {
  404                 SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
  405                 if (xprt->xp_upcallset) {
  406                         xprt->xp_upcallset = 0;
  407                         soupcall_clear(xprt->xp_socket, SO_RCV);
  408                 }
  409                 SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
  410                 xprt_inactive_self(xprt);
  411                 sx_xunlock(&xprt->xp_lock);
  412                 return (FALSE);
  413         }
  414 
  415         sx_xunlock(&xprt->xp_lock);
  416 
  417         sa = NULL;
  418         error = soaccept(so, &sa);
  419 
  420         if (error) {
  421                 /*
  422                  * XXX not sure if I need to call sofree or soclose here.
  423                  */
  424                 if (sa)
  425                         free(sa, M_SONAME);
  426                 return (FALSE);
  427         }
  428 
  429         /*
  430          * svc_vc_create_conn will call xprt_register - we don't need
  431          * to do anything with the new connection except derefence it.
  432          */
  433         new_xprt = svc_vc_create_conn(xprt->xp_pool, so, sa);
  434         if (!new_xprt) {
  435                 soclose(so);
  436         } else {
  437                 SVC_RELEASE(new_xprt);
  438         }
  439 
  440         free(sa, M_SONAME);
  441 
  442         return (FALSE); /* there is never an rpc msg to be processed */
  443 }
  444 
  445 /*ARGSUSED*/
  446 static enum xprt_stat
  447 svc_vc_rendezvous_stat(SVCXPRT *xprt)
  448 {
  449 
  450         return (XPRT_IDLE);
  451 }
  452 
  453 static void
  454 svc_vc_destroy_common(SVCXPRT *xprt)
  455 {
  456         SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
  457         if (xprt->xp_upcallset) {
  458                 xprt->xp_upcallset = 0;
  459                 soupcall_clear(xprt->xp_socket, SO_RCV);
  460         }
  461         SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
  462 
  463         if (xprt->xp_socket)
  464                 (void)soclose(xprt->xp_socket);
  465 
  466         if (xprt->xp_netid)
  467                 (void) mem_free(xprt->xp_netid, strlen(xprt->xp_netid) + 1);
  468         svc_xprt_free(xprt);
  469 }
  470 
  471 static void
  472 svc_vc_rendezvous_destroy(SVCXPRT *xprt)
  473 {
  474 
  475         svc_vc_destroy_common(xprt);
  476 }
  477 
  478 static void
  479 svc_vc_destroy(SVCXPRT *xprt)
  480 {
  481         struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
  482 
  483         svc_vc_destroy_common(xprt);
  484 
  485         if (cd->mreq)
  486                 m_freem(cd->mreq);
  487         if (cd->mpending)
  488                 m_freem(cd->mpending);
  489         mem_free(cd, sizeof(*cd));
  490 }
  491 
  492 static void
  493 svc_vc_backchannel_destroy(SVCXPRT *xprt)
  494 {
  495         struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
  496         struct mbuf *m, *m2;
  497 
  498         svc_xprt_free(xprt);
  499         m = cd->mreq;
  500         while (m != NULL) {
  501                 m2 = m;
  502                 m = m->m_nextpkt;
  503                 m_freem(m2);
  504         }
  505         mem_free(cd, sizeof(*cd));
  506 }
  507 
  508 /*ARGSUSED*/
  509 static bool_t
  510 svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in)
  511 {
  512         return (FALSE);
  513 }
  514 
  515 static bool_t
  516 svc_vc_rendezvous_control(SVCXPRT *xprt, const u_int rq, void *in)
  517 {
  518 
  519         return (FALSE);
  520 }
  521 
  522 static bool_t
  523 svc_vc_backchannel_control(SVCXPRT *xprt, const u_int rq, void *in)
  524 {
  525 
  526         return (FALSE);
  527 }
  528 
  529 static enum xprt_stat
  530 svc_vc_stat(SVCXPRT *xprt)
  531 {
  532         struct cf_conn *cd;
  533 
  534         cd = (struct cf_conn *)(xprt->xp_p1);
  535 
  536         if (cd->strm_stat == XPRT_DIED)
  537                 return (XPRT_DIED);
  538 
  539         if (cd->mreq != NULL && cd->resid == 0 && cd->eor)
  540                 return (XPRT_MOREREQS);
  541 
  542         if (soreadable(xprt->xp_socket))
  543                 return (XPRT_MOREREQS);
  544 
  545         return (XPRT_IDLE);
  546 }
  547 
  548 static bool_t
  549 svc_vc_ack(SVCXPRT *xprt, uint32_t *ack)
  550 {
  551 
  552         *ack = atomic_load_acq_32(&xprt->xp_snt_cnt);
  553         *ack -= sbused(&xprt->xp_socket->so_snd);
  554         return (TRUE);
  555 }
  556 
  557 static enum xprt_stat
  558 svc_vc_backchannel_stat(SVCXPRT *xprt)
  559 {
  560         struct cf_conn *cd;
  561 
  562         cd = (struct cf_conn *)(xprt->xp_p1);
  563 
  564         if (cd->mreq != NULL)
  565                 return (XPRT_MOREREQS);
  566 
  567         return (XPRT_IDLE);
  568 }
  569 
  570 /*
  571  * If we have an mbuf chain in cd->mpending, try to parse a record from it,
  572  * leaving the result in cd->mreq. If we don't have a complete record, leave
  573  * the partial result in cd->mreq and try to read more from the socket.
  574  */
  575 static int
  576 svc_vc_process_pending(SVCXPRT *xprt)
  577 {
  578         struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
  579         struct socket *so = xprt->xp_socket;
  580         struct mbuf *m;
  581 
  582         /*
  583          * If cd->resid is non-zero, we have part of the
  584          * record already, otherwise we are expecting a record
  585          * marker.
  586          */
  587         if (!cd->resid && cd->mpending) {
  588                 /*
  589                  * See if there is enough data buffered to
  590                  * make up a record marker. Make sure we can
  591                  * handle the case where the record marker is
  592                  * split across more than one mbuf.
  593                  */
  594                 size_t n = 0;
  595                 uint32_t header;
  596 
  597                 m = cd->mpending;
  598                 while (n < sizeof(uint32_t) && m) {
  599                         n += m->m_len;
  600                         m = m->m_next;
  601                 }
  602                 if (n < sizeof(uint32_t)) {
  603                         so->so_rcv.sb_lowat = sizeof(uint32_t) - n;
  604                         return (FALSE);
  605                 }
  606                 m_copydata(cd->mpending, 0, sizeof(header),
  607                     (char *)&header);
  608                 header = ntohl(header);
  609                 cd->eor = (header & 0x80000000) != 0;
  610                 cd->resid = header & 0x7fffffff;
  611                 m_adj(cd->mpending, sizeof(uint32_t));
  612         }
  613 
  614         /*
  615          * Start pulling off mbufs from cd->mpending
  616          * until we either have a complete record or
  617          * we run out of data. We use m_split to pull
  618          * data - it will pull as much as possible and
  619          * split the last mbuf if necessary.
  620          */
  621         while (cd->mpending && cd->resid) {
  622                 m = cd->mpending;
  623                 if (cd->mpending->m_next
  624                     || cd->mpending->m_len > cd->resid)
  625                         cd->mpending = m_split(cd->mpending,
  626                             cd->resid, M_WAITOK);
  627                 else
  628                         cd->mpending = NULL;
  629                 if (cd->mreq)
  630                         m_last(cd->mreq)->m_next = m;
  631                 else
  632                         cd->mreq = m;
  633                 while (m) {
  634                         cd->resid -= m->m_len;
  635                         m = m->m_next;
  636                 }
  637         }
  638 
  639         /*
  640          * Block receive upcalls if we have more data pending,
  641          * otherwise report our need.
  642          */
  643         if (cd->mpending)
  644                 so->so_rcv.sb_lowat = INT_MAX;
  645         else
  646                 so->so_rcv.sb_lowat =
  647                     imax(1, imin(cd->resid, so->so_rcv.sb_hiwat / 2));
  648         return (TRUE);
  649 }
  650 
  651 static bool_t
  652 svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
  653     struct sockaddr **addrp, struct mbuf **mp)
  654 {
  655         struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
  656         struct uio uio;
  657         struct mbuf *m;
  658         struct socket* so = xprt->xp_socket;
  659         XDR xdrs;
  660         int error, rcvflag;
  661         uint32_t xid_plus_direction[2];
  662 
  663         /*
  664          * Serialise access to the socket and our own record parsing
  665          * state.
  666          */
  667         sx_xlock(&xprt->xp_lock);
  668 
  669         for (;;) {
  670                 /* If we have no request ready, check pending queue. */
  671                 while (cd->mpending &&
  672                     (cd->mreq == NULL || cd->resid != 0 || !cd->eor)) {
  673                         if (!svc_vc_process_pending(xprt))
  674                                 break;
  675                 }
  676 
  677                 /* Process and return complete request in cd->mreq. */
  678                 if (cd->mreq != NULL && cd->resid == 0 && cd->eor) {
  679 
  680                         /*
  681                          * Now, check for a backchannel reply.
  682                          * The XID is in the first uint32_t of the reply
  683                          * and the message direction is the second one.
  684                          */
  685                         if ((cd->mreq->m_len >= sizeof(xid_plus_direction) ||
  686                             m_length(cd->mreq, NULL) >=
  687                             sizeof(xid_plus_direction)) &&
  688                             xprt->xp_p2 != NULL) {
  689                                 m_copydata(cd->mreq, 0,
  690                                     sizeof(xid_plus_direction),
  691                                     (char *)xid_plus_direction);
  692                                 xid_plus_direction[0] =
  693                                     ntohl(xid_plus_direction[0]);
  694                                 xid_plus_direction[1] =
  695                                     ntohl(xid_plus_direction[1]);
  696                                 /* Check message direction. */
  697                                 if (xid_plus_direction[1] == REPLY) {
  698                                         clnt_bck_svccall(xprt->xp_p2,
  699                                             cd->mreq,
  700                                             xid_plus_direction[0]);
  701                                         cd->mreq = NULL;
  702                                         continue;
  703                                 }
  704                         }
  705 
  706                         xdrmbuf_create(&xdrs, cd->mreq, XDR_DECODE);
  707                         cd->mreq = NULL;
  708 
  709                         /* Check for next request in a pending queue. */
  710                         svc_vc_process_pending(xprt);
  711                         if (cd->mreq == NULL || cd->resid != 0) {
  712                                 SOCKBUF_LOCK(&so->so_rcv);
  713                                 if (!soreadable(so))
  714                                         xprt_inactive_self(xprt);
  715                                 SOCKBUF_UNLOCK(&so->so_rcv);
  716                         }
  717 
  718                         sx_xunlock(&xprt->xp_lock);
  719 
  720                         if (! xdr_callmsg(&xdrs, msg)) {
  721                                 XDR_DESTROY(&xdrs);
  722                                 return (FALSE);
  723                         }
  724 
  725                         *addrp = NULL;
  726                         *mp = xdrmbuf_getall(&xdrs);
  727                         XDR_DESTROY(&xdrs);
  728 
  729                         return (TRUE);
  730                 }
  731 
  732                 /*
  733                  * The socket upcall calls xprt_active() which will eventually
  734                  * cause the server to call us here. We attempt to
  735                  * read as much as possible from the socket and put
  736                  * the result in cd->mpending. If the read fails,
  737                  * we have drained both cd->mpending and the socket so
  738                  * we can call xprt_inactive().
  739                  */
  740                 uio.uio_resid = 1000000000;
  741                 uio.uio_td = curthread;
  742                 m = NULL;
  743                 rcvflag = MSG_DONTWAIT;
  744                 error = soreceive(so, NULL, &uio, &m, NULL, &rcvflag);
  745 
  746                 if (error == EWOULDBLOCK) {
  747                         /*
  748                          * We must re-test for readability after
  749                          * taking the lock to protect us in the case
  750                          * where a new packet arrives on the socket
  751                          * after our call to soreceive fails with
  752                          * EWOULDBLOCK.
  753                          */
  754                         SOCKBUF_LOCK(&so->so_rcv);
  755                         if (!soreadable(so))
  756                                 xprt_inactive_self(xprt);
  757                         SOCKBUF_UNLOCK(&so->so_rcv);
  758                         sx_xunlock(&xprt->xp_lock);
  759                         return (FALSE);
  760                 }
  761 
  762                 if (error) {
  763                         SOCKBUF_LOCK(&so->so_rcv);
  764                         if (xprt->xp_upcallset) {
  765                                 xprt->xp_upcallset = 0;
  766                                 soupcall_clear(so, SO_RCV);
  767                         }
  768                         SOCKBUF_UNLOCK(&so->so_rcv);
  769                         xprt_inactive_self(xprt);
  770                         cd->strm_stat = XPRT_DIED;
  771                         sx_xunlock(&xprt->xp_lock);
  772                         return (FALSE);
  773                 }
  774 
  775                 if (!m) {
  776                         /*
  777                          * EOF - the other end has closed the socket.
  778                          */
  779                         xprt_inactive_self(xprt);
  780                         cd->strm_stat = XPRT_DIED;
  781                         sx_xunlock(&xprt->xp_lock);
  782                         return (FALSE);
  783                 }
  784 
  785                 if (cd->mpending)
  786                         m_last(cd->mpending)->m_next = m;
  787                 else
  788                         cd->mpending = m;
  789         }
  790 }
  791 
  792 static bool_t
  793 svc_vc_backchannel_recv(SVCXPRT *xprt, struct rpc_msg *msg,
  794     struct sockaddr **addrp, struct mbuf **mp)
  795 {
  796         struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
  797         struct ct_data *ct;
  798         struct mbuf *m;
  799         XDR xdrs;
  800 
  801         sx_xlock(&xprt->xp_lock);
  802         ct = (struct ct_data *)xprt->xp_p2;
  803         if (ct == NULL) {
  804                 sx_xunlock(&xprt->xp_lock);
  805                 return (FALSE);
  806         }
  807         mtx_lock(&ct->ct_lock);
  808         m = cd->mreq;
  809         if (m == NULL) {
  810                 xprt_inactive_self(xprt);
  811                 mtx_unlock(&ct->ct_lock);
  812                 sx_xunlock(&xprt->xp_lock);
  813                 return (FALSE);
  814         }
  815         cd->mreq = m->m_nextpkt;
  816         mtx_unlock(&ct->ct_lock);
  817         sx_xunlock(&xprt->xp_lock);
  818 
  819         xdrmbuf_create(&xdrs, m, XDR_DECODE);
  820         if (! xdr_callmsg(&xdrs, msg)) {
  821                 XDR_DESTROY(&xdrs);
  822                 return (FALSE);
  823         }
  824         *addrp = NULL;
  825         *mp = xdrmbuf_getall(&xdrs);
  826         XDR_DESTROY(&xdrs);
  827         return (TRUE);
  828 }
  829 
  830 static bool_t
  831 svc_vc_reply(SVCXPRT *xprt, struct rpc_msg *msg,
  832     struct sockaddr *addr, struct mbuf *m, uint32_t *seq)
  833 {
  834         XDR xdrs;
  835         struct mbuf *mrep;
  836         bool_t stat = TRUE;
  837         int error, len;
  838 
  839         /*
  840          * Leave space for record mark.
  841          */
  842         mrep = m_gethdr(M_WAITOK, MT_DATA);
  843         mrep->m_data += sizeof(uint32_t);
  844 
  845         xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
  846 
  847         if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
  848             msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
  849                 if (!xdr_replymsg(&xdrs, msg))
  850                         stat = FALSE;
  851                 else
  852                         xdrmbuf_append(&xdrs, m);
  853         } else {
  854                 stat = xdr_replymsg(&xdrs, msg);
  855         }
  856 
  857         if (stat) {
  858                 m_fixhdr(mrep);
  859 
  860                 /*
  861                  * Prepend a record marker containing the reply length.
  862                  */
  863                 M_PREPEND(mrep, sizeof(uint32_t), M_WAITOK);
  864                 len = mrep->m_pkthdr.len;
  865                 *mtod(mrep, uint32_t *) =
  866                         htonl(0x80000000 | (len - sizeof(uint32_t)));
  867                 atomic_add_32(&xprt->xp_snd_cnt, len);
  868                 error = sosend(xprt->xp_socket, NULL, NULL, mrep, NULL,
  869                     0, curthread);
  870                 if (!error) {
  871                         atomic_add_rel_32(&xprt->xp_snt_cnt, len);
  872                         if (seq)
  873                                 *seq = xprt->xp_snd_cnt;
  874                         stat = TRUE;
  875                 } else
  876                         atomic_subtract_32(&xprt->xp_snd_cnt, len);
  877         } else {
  878                 m_freem(mrep);
  879         }
  880 
  881         XDR_DESTROY(&xdrs);
  882 
  883         return (stat);
  884 }
  885 
  886 static bool_t
  887 svc_vc_backchannel_reply(SVCXPRT *xprt, struct rpc_msg *msg,
  888     struct sockaddr *addr, struct mbuf *m, uint32_t *seq)
  889 {
  890         struct ct_data *ct;
  891         XDR xdrs;
  892         struct mbuf *mrep;
  893         bool_t stat = TRUE;
  894         int error;
  895 
  896         /*
  897          * Leave space for record mark.
  898          */
  899         mrep = m_gethdr(M_WAITOK, MT_DATA);
  900         mrep->m_data += sizeof(uint32_t);
  901 
  902         xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
  903 
  904         if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
  905             msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
  906                 if (!xdr_replymsg(&xdrs, msg))
  907                         stat = FALSE;
  908                 else
  909                         xdrmbuf_append(&xdrs, m);
  910         } else {
  911                 stat = xdr_replymsg(&xdrs, msg);
  912         }
  913 
  914         if (stat) {
  915                 m_fixhdr(mrep);
  916 
  917                 /*
  918                  * Prepend a record marker containing the reply length.
  919                  */
  920                 M_PREPEND(mrep, sizeof(uint32_t), M_WAITOK);
  921                 *mtod(mrep, uint32_t *) =
  922                         htonl(0x80000000 | (mrep->m_pkthdr.len
  923                                 - sizeof(uint32_t)));
  924                 sx_xlock(&xprt->xp_lock);
  925                 ct = (struct ct_data *)xprt->xp_p2;
  926                 if (ct != NULL)
  927                         error = sosend(ct->ct_socket, NULL, NULL, mrep, NULL,
  928                             0, curthread);
  929                 else
  930                         error = EPIPE;
  931                 sx_xunlock(&xprt->xp_lock);
  932                 if (!error) {
  933                         stat = TRUE;
  934                 }
  935         } else {
  936                 m_freem(mrep);
  937         }
  938 
  939         XDR_DESTROY(&xdrs);
  940 
  941         return (stat);
  942 }
  943 
  944 static bool_t
  945 svc_vc_null()
  946 {
  947 
  948         return (FALSE);
  949 }
  950 
  951 static int
  952 svc_vc_soupcall(struct socket *so, void *arg, int waitflag)
  953 {
  954         SVCXPRT *xprt = (SVCXPRT *) arg;
  955 
  956         if (soreadable(xprt->xp_socket))
  957                 xprt_active(xprt);
  958         return (SU_OK);
  959 }
  960 
  961 #if 0
  962 /*
  963  * Get the effective UID of the sending process. Used by rpcbind, keyserv
  964  * and rpc.yppasswdd on AF_LOCAL.
  965  */
  966 int
  967 __rpc_get_local_uid(SVCXPRT *transp, uid_t *uid) {
  968         int sock, ret;
  969         gid_t egid;
  970         uid_t euid;
  971         struct sockaddr *sa;
  972 
  973         sock = transp->xp_fd;
  974         sa = (struct sockaddr *)transp->xp_rtaddr;
  975         if (sa->sa_family == AF_LOCAL) {
  976                 ret = getpeereid(sock, &euid, &egid);
  977                 if (ret == 0)
  978                         *uid = euid;
  979                 return (ret);
  980         } else
  981                 return (-1);
  982 }
  983 #endif

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