lib/libc/rpc/svc_tcp.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user.
   8  *
   9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  12  *
  13  * Sun RPC is provided with no support and without any obligation on the
  14  * part of Sun Microsystems, Inc. to assist in its use, correction,
  15  * modification or enhancement.
  16  *
  17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  19  * OR ANY PART THEREOF.
  20  *
  21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  22  * or profits or other special, indirect and consequential damages, even if
  23  * Sun has been advised of the possibility of such damages.
  24  *
  25  * Sun Microsystems, Inc.
  26  * 2550 Garcia Avenue
  27  * Mountain View, California  94043
  28  *
  29  * @(#)svc_tcp.c 1.21 87/08/11 Copyr 1984 Sun Micro
  30  * @(#)svc_tcp.c        2.2 88/08/01 4.0 RPCSRC
  31  * $FreeBSD: src/lib/libc/rpc/svc_tcp.c,v 1.18.2.3 2001/09/05 22:29:23 dec Exp $
  32  * $DragonFly: src/lib/libc/rpc/svc_tcp.c,v 1.5 2005/11/13 12:27:04 swildner Exp $
  33  */
  34
  35 /*
  36  * svc_tcp.c, Server side for TCP/IP based RPC.
  37  *
  38  * Copyright (C) 1984, Sun Microsystems, Inc.
  39  *
  40  * Actually implements two flavors of transporter -
  41  * a tcp rendezvouser (a listner and connection establisher)
  42  * and a record/tcp stream.
  43  */
  44
  45 #include "namespace.h"
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <unistd.h>
  49 #include <string.h>
  50 #include <rpc/rpc.h>
  51 #include <sys/socket.h>
  52 #include <sys/ioctl.h>
  53 #include <errno.h>
  54 #include "un-namespace.h"
  55
  56 /*
  57  * Ops vector for TCP/IP based rpc service handle
  58  */
  59 static bool_t           svctcp_recv();
  60 static enum xprt_stat   svctcp_stat();
  61 static bool_t           svctcp_getargs();
  62 static bool_t           svctcp_reply();
  63 static bool_t           svctcp_freeargs();
  64 static void             svctcp_destroy();
  65
  66 static struct xp_ops svctcp_op = {
  67         svctcp_recv,
  68         svctcp_stat,
  69         svctcp_getargs,
  70         svctcp_reply,
  71         svctcp_freeargs,
  72         svctcp_destroy
  73 };
  74
  75 /*
  76  * Ops vector for TCP/IP rendezvous handler
  77  */
  78 static bool_t           rendezvous_request();
  79 static enum xprt_stat   rendezvous_stat();
  80
  81 static struct xp_ops svctcp_rendezvous_op = {
  82         rendezvous_request,
  83         rendezvous_stat,
  84         (bool_t (*)())abort,
  85         (bool_t (*)())abort,
  86         (bool_t (*)())abort,
  87         svctcp_destroy
  88 };
  89
  90 static int readtcp(), writetcp();
  91 static SVCXPRT *makefd_xprt();
  92
  93 struct tcp_rendezvous { /* kept in xprt->xp_p1 */
  94         u_int sendsize;
  95         u_int recvsize;
  96 };
  97
  98 struct tcp_conn {  /* kept in xprt->xp_p1 */
  99         enum xprt_stat strm_stat;
 100         u_long x_id;
 101         XDR xdrs;
 102         char verf_body[MAX_AUTH_BYTES];
 103 };
 104
 105 /*
 106  * Usage:
 107  *      xprt = svctcp_create(sock, send_buf_size, recv_buf_size);
 108  *
 109  * Creates, registers, and returns a (rpc) tcp based transporter.
 110  * Once *xprt is initialized, it is registered as a transporter
 111  * see (svc.h, xprt_register).  This routine returns
 112  * a NULL if a problem occurred.
 113  *
 114  * If sock<0 then a socket is created, else sock is used.
 115  * If the socket, sock is not bound to a port then svctcp_create
 116  * binds it to an arbitrary port.  The routine then starts a tcp
 117  * listener on the socket's associated port.  In any (successful) case,
 118  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
 119  * associated port number.
 120  *
 121  * Since tcp streams do buffered io similar to stdio, the caller can specify
 122  * how big the send and receive buffers are via the second and third parms;
 123  * 0 => use the system default.
 124  */
 125 SVCXPRT *
 126 svctcp_create(int sock, u_int sendsize, u_int recvsize)
 127 {
 128         bool_t madesock = FALSE;
 129         SVCXPRT *xprt;
 130         struct tcp_rendezvous *r;
 131         struct sockaddr_in addr;
 132         int len = sizeof(struct sockaddr_in);
 133         int on;
 134
 135         if (sock == RPC_ANYSOCK) {
 136                 if ((sock = _socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
 137                         perror("svctcp_.c - tcp socket creation problem");
 138                         return ((SVCXPRT *)NULL);
 139                 }
 140                 madesock = TRUE;
 141         }
 142         on = 1;
 143         if (_ioctl(sock, FIONBIO, &on) < 0) {
 144                 perror("svc_tcp.c - cannot turn on non-blocking mode");
 145                 if (madesock)
 146                        _close(sock);
 147                 return ((SVCXPRT *)NULL);
 148         }
 149         memset(&addr, 0, sizeof (addr));
 150         addr.sin_len = sizeof(struct sockaddr_in);
 151         addr.sin_family = AF_INET;
 152         if (bindresvport(sock, &addr)) {
 153                 addr.sin_port = 0;
 154                 _bind(sock, (struct sockaddr *)&addr, len);
 155         }
 156         if ((_getsockname(sock, (struct sockaddr *)&addr, &len) != 0)  ||
 157             (_listen(sock, 2) != 0)) {
 158                 perror("svctcp_.c - cannot getsockname or listen");
 159                 if (madesock)
 160                        _close(sock);
 161                 return ((SVCXPRT *)NULL);
 162         }
 163         r = (struct tcp_rendezvous *)mem_alloc(sizeof(*r));
 164         if (r == NULL) {
 165                 fprintf(stderr, "svctcp_create: out of memory\n");
 166                 return (NULL);
 167         }
 168         r->sendsize = sendsize;
 169         r->recvsize = recvsize;
 170         xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
 171         if (xprt == NULL) {
 172                 fprintf(stderr, "svctcp_create: out of memory\n");
 173                 return (NULL);
 174         }
 175         xprt->xp_p2 = NULL;
 176         xprt->xp_p1 = (caddr_t)r;
 177         xprt->xp_verf = _null_auth;
 178         xprt->xp_ops = &svctcp_rendezvous_op;
 179         xprt->xp_port = ntohs(addr.sin_port);
 180         xprt->xp_sock = sock;
 181         xprt_register(xprt);
 182         return (xprt);
 183 }
 184
 185 /*
 186  * Like svtcp_create(), except the routine takes any *open* UNIX file
 187  * descriptor as its first input.
 188  */
 189 SVCXPRT *
 190 svcfd_create(int fd, u_int sendsize, u_int recvsize)
 191 {
 192
 193         return (makefd_xprt(fd, sendsize, recvsize));
 194 }
 195
 196 static SVCXPRT *
 197 makefd_xprt(int fd, u_int sendsize, u_int recvsize)
 198 {
 199         SVCXPRT *xprt;
 200         struct tcp_conn *cd;
 201
 202         xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
 203         if (xprt == (SVCXPRT *)NULL) {
 204                 fprintf(stderr, "svc_tcp: makefd_xprt: out of memory\n");
 205                 goto done;
 206         }
 207         cd = (struct tcp_conn *)mem_alloc(sizeof(struct tcp_conn));
 208         if (cd == (struct tcp_conn *)NULL) {
 209                 fprintf(stderr, "svc_tcp: makefd_xprt: out of memory\n");
 210                 mem_free((char *) xprt, sizeof(SVCXPRT));
 211                 xprt = (SVCXPRT *)NULL;
 212                 goto done;
 213         }
 214         cd->strm_stat = XPRT_IDLE;
 215         xdrrec_create(&(cd->xdrs), sendsize, recvsize,
 216             (caddr_t)xprt, readtcp, writetcp);
 217         xprt->xp_p2 = NULL;
 218         xprt->xp_p1 = (caddr_t)cd;
 219         xprt->xp_verf.oa_base = cd->verf_body;
 220         xprt->xp_addrlen = 0;
 221         xprt->xp_ops = &svctcp_op;  /* truely deals with calls */
 222         xprt->xp_port = 0;  /* this is a connection, not a rendezvouser */
 223         xprt->xp_sock = fd;
 224         xprt_register(xprt);
 225     done:
 226         return (xprt);
 227 }
 228
 229 static bool_t
 230 rendezvous_request(SVCXPRT *xprt)
 231 {
 232         int sock;
 233         struct tcp_rendezvous *r;
 234         struct sockaddr_in addr;
 235         int len;
 236         int off;
 237
 238         r = (struct tcp_rendezvous *)xprt->xp_p1;
 239     again:
 240         len = sizeof(struct sockaddr_in);
 241         if ((sock = _accept(xprt->xp_sock, (struct sockaddr *)&addr,
 242             &len)) < 0) {
 243                 if (errno == EINTR)
 244                         goto again;
 245                return (FALSE);
 246         }
 247         /*
 248          * Guard against FTP bounce attacks.
 249          */
 250         if (addr.sin_port == htons(20)) {
 251                 _close(sock);
 252                 return (FALSE);
 253         }
 254         /*
 255          * The listening socket is in FIONBIO mode and we inherit it.
 256          */
 257         off = 0;
 258         if (_ioctl(sock, FIONBIO, &off) < 0) {
 259                 _close(sock);
 260                 return (FALSE);
 261         }
 262         /*
 263          * make a new transporter (re-uses xprt)
 264          */
 265         xprt = makefd_xprt(sock, r->sendsize, r->recvsize);
 266         xprt->xp_raddr = addr;
 267         xprt->xp_addrlen = len;
 268         return (FALSE); /* there is never an rpc msg to be processed */
 269 }
 270
 271 static enum xprt_stat
 272 rendezvous_stat(void)
 273 {
 274
 275         return (XPRT_IDLE);
 276 }
 277
 278 static void
 279 svctcp_destroy(SVCXPRT *xprt)
 280 {
 281         struct tcp_conn *cd = (struct tcp_conn *)xprt->xp_p1;
 282
 283         xprt_unregister(xprt);
 284         _close(xprt->xp_sock);
 285         if (xprt->xp_port != 0) {
 286                 /* a rendezvouser socket */
 287                 xprt->xp_port = 0;
 288         } else {
 289                 /* an actual connection socket */
 290                 XDR_DESTROY(&(cd->xdrs));
 291         }
 292         mem_free((caddr_t)cd, sizeof(struct tcp_conn));
 293         mem_free((caddr_t)xprt, sizeof(SVCXPRT));
 294 }
 295
 296 /*
 297  * All read operations timeout after 35 seconds.
 298  * A timeout is fatal for the connection.
 299  */
 300 static struct timeval wait_per_try = { 35, 0 };
 301
 302 /*
 303  * reads data from the tcp conection.
 304  * any error is fatal and the connection is closed.
 305  * (And a read of zero bytes is a half closed stream => error.)
 306  *
 307  * Note: we have to be careful here not to allow ourselves to become
 308  * blocked too long in this routine. While we're waiting for data from one
 309  * client, another client may be trying to connect. To avoid this situation,
 310  * some code from svc_run() is transplanted here: the _select() loop checks
 311  * all RPC descriptors including the one we want and calls svc_getreqset2()
 312  * to handle new requests if any are detected.
 313  */
 314 static int
 315 readtcp(SVCXPRT *xprt, caddr_t buf, int len)
 316 {
 317         int sock = xprt->xp_sock;
 318         struct timeval start, delta, tv;
 319         struct timeval tmp1, tmp2;
 320         fd_set *fds;
 321         extern fd_set           *__svc_fdset;
 322         extern int              __svc_fdsetsize;
 323
 324         delta = wait_per_try;
 325         fds = NULL;
 326         gettimeofday(&start, NULL);
 327         do {
 328                 int bytes = howmany(__svc_fdsetsize, NFDBITS) *
 329                                 sizeof(fd_mask);
 330                 if (fds != NULL)
 331                         free(fds);
 332                 fds = (fd_set *)malloc(bytes);
 333                 if (fds == NULL)
 334                         goto fatal_err;
 335                 memcpy(fds, __svc_fdset, bytes);
 336
 337                 /* XXX we know the other bits are still clear */
 338                 FD_SET(sock, fds);
 339                 tv = delta;     /* in case _select() implements writeback */
 340                 switch (_select(svc_maxfd + 1, fds, NULL, NULL, &tv)) {
 341                 case -1:
 342                         memset(fds, 0, bytes);
 343                         if (errno != EINTR)
 344                                 goto fatal_err;
 345                         gettimeofday(&tmp1, NULL);
 346                         timersub(&tmp1, &start, &tmp2);
 347                         timersub(&wait_per_try, &tmp2, &tmp1);
 348                         if (tmp1.tv_sec < 0 || !timerisset(&tmp1))
 349                                 goto fatal_err;
 350                         delta = tmp1;
 351                         continue;
 352                 case 0:
 353                         goto fatal_err;
 354                 default:
 355                         if (!FD_ISSET(sock, fds)) {
 356                                 svc_getreqset2(fds, svc_maxfd + 1);
 357                                 gettimeofday(&tmp1, NULL);
 358                                 timersub(&tmp1, &start, &tmp2);
 359                                 timersub(&wait_per_try, &tmp2, &tmp1);
 360                                 if (tmp1.tv_sec < 0 || !timerisset(&tmp1))
 361                                         goto fatal_err;
 362                                 delta = tmp1;
 363                                 continue;
 364                         }
 365                 }
 366         } while (!FD_ISSET(sock, fds));
 367         if ((len = _read(sock, buf, len)) > 0) {
 368                 if (fds != NULL)
 369                         free(fds);
 370                 return (len);
 371         }
 372 fatal_err:
 373         ((struct tcp_conn *)(xprt->xp_p1))->strm_stat = XPRT_DIED;
 374         if (fds != NULL)
 375                 free(fds);
 376         return (-1);
 377 }
 378
 379 /*
 380  * writes data to the tcp connection.
 381  * Any error is fatal and the connection is closed.
 382  */
 383 static int
 384 writetcp(SVCXPRT *xprt, caddr_t buf, int len)
 385 {
 386         int i, cnt;
 387
 388         for (cnt = len; cnt > 0; cnt -= i, buf += i) {
 389                 if ((i = _write(xprt->xp_sock, buf, cnt)) < 0) {
 390                         ((struct tcp_conn *)(xprt->xp_p1))->strm_stat =
 391                             XPRT_DIED;
 392                         return (-1);
 393                 }
 394         }
 395         return (len);
 396 }
 397
 398 static enum xprt_stat
 399 svctcp_stat(SVCXPRT *xprt)
 400 {
 401         struct tcp_conn *cd =
 402             (struct tcp_conn *)(xprt->xp_p1);
 403
 404         if (cd->strm_stat == XPRT_DIED)
 405                 return (XPRT_DIED);
 406         if (! xdrrec_eof(&(cd->xdrs)))
 407                 return (XPRT_MOREREQS);
 408         return (XPRT_IDLE);
 409 }
 410
 411 static bool_t
 412 svctcp_recv(SVCXPRT *xprt, struct rpc_msg *msg)
 413 {
 414         struct tcp_conn *cd =
 415             (struct tcp_conn *)(xprt->xp_p1);
 416         XDR *xdrs = &(cd->xdrs);
 417
 418         xdrs->x_op = XDR_DECODE;
 419         xdrrec_skiprecord(xdrs);
 420         if (xdr_callmsg(xdrs, msg)) {
 421                 cd->x_id = msg->rm_xid;
 422                 return (TRUE);
 423         }
 424         cd->strm_stat = XPRT_DIED;      /* XXXX */
 425         return (FALSE);
 426 }
 427
 428 static bool_t
 429 svctcp_getargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 430 {
 431
 432         return ((*xdr_args)(&(((struct tcp_conn *)(xprt->xp_p1))->xdrs), args_ptr));
 433 }
 434
 435 static bool_t
 436 svctcp_freeargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 437 {
 438         XDR *xdrs =
 439             &(((struct tcp_conn *)(xprt->xp_p1))->xdrs);
 440
 441         xdrs->x_op = XDR_FREE;
 442         return ((*xdr_args)(xdrs, args_ptr));
 443 }
 444
 445 static bool_t
 446 svctcp_reply(SVCXPRT *xprt, struct rpc_msg *msg)
 447 {
 448         struct tcp_conn *cd =
 449             (struct tcp_conn *)(xprt->xp_p1);
 450         XDR *xdrs = &(cd->xdrs);
 451         bool_t stat;
 452
 453         xdrs->x_op = XDR_ENCODE;
 454         msg->rm_xid = cd->x_id;
 455         stat = xdr_replymsg(xdrs, msg);
 456         xdrrec_endofrecord(xdrs, TRUE);
 457         return (stat);
 458 }