usr.sbin/lpr/common_source/net.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * (c) UNIX System Laboratories, Inc.
   5  * All or some portions of this file are derived from material licensed
   6  * to the University of California by American Telephone and Telegraph
   7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   8  * the permission of UNIX System Laboratories, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      From: @(#)common.c      8.5 (Berkeley) 4/28/95
  39  *
  40  * $FreeBSD: src/usr.sbin/lpr/common_source/net.c,v 1.3.2.4 2001/06/25 01:00:56 gad Exp $
  41  * $DragonFly: src/usr.sbin/lpr/common_source/net.c,v 1.3 2004/12/18 22:48:03 swildner Exp $
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/socket.h>
  46 #include <sys/stat.h>
  47 #include <sys/time.h>
  48 #include <sys/uio.h>
  49
  50 #include <netinet/in.h>
  51 #include <arpa/inet.h>
  52 #include <netdb.h>
  53
  54 #include <dirent.h>             /* required for lp.h, not used here */
  55 #include <errno.h>
  56 #include <stdarg.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61
  62 #include "lp.h"
  63 #include "lp.local.h"
  64 #include "pathnames.h"
  65
  66 /*
  67  * 'local_host' is always the hostname of the machine which is running
  68  * lpr (lpd, whatever), while 'from_host' either points at 'local_host'
  69  * or points at a different buffer when receiving a job from a remote
  70  * machine (and that buffer has the hostname of that remote machine).
  71  */
  72 char             local_host[MAXHOSTNAMELEN];    /* host running lpd/lpr */
  73 const char      *from_host = local_host;        /* client's machine name */
  74 const char      *from_ip = "";          /* client machine's IP address */
  75
  76 #ifdef INET6
  77 u_char  family = PF_UNSPEC;
  78 #else
  79 u_char  family = PF_INET;
  80 #endif
  81
  82 extern uid_t    uid, euid;
  83
  84 /*
  85  * Create a TCP connection to host "rhost" at port "rport".
  86  * If rport == 0, then use the printer service port.
  87  * Most of this code comes from rcmd.c.
  88  */
  89 int
  90 getport(const struct printer *pp, const char *rhost, int rport)
  91 {
  92         struct addrinfo hints, *res, *ai;
  93         int s, timo = 1, lport = IPPORT_RESERVED - 1;
  94         int err, refused = 0;
  95
  96         /*
  97          * Get the host address and port number to connect to.
  98          */
  99         if (rhost == NULL)
 100                 fatal(pp, "no remote host to connect to");
 101         memset(&hints, 0, sizeof(hints));
 102         hints.ai_family = family;
 103         hints.ai_socktype = SOCK_STREAM;
 104         hints.ai_protocol = 0;
 105         err = getaddrinfo(rhost, (rport == 0 ? "printer" : NULL),
 106                           &hints, &res);
 107         if (err)
 108                 fatal(pp, "%s\n", gai_strerror(err));
 109         if (rport != 0)
 110                 ((struct sockaddr_in *) res->ai_addr)->sin_port = htons(rport);
 111
 112         /*
 113          * Try connecting to the server.
 114          */
 115         ai = res;
 116 retry:
 117         seteuid(euid);
 118         s = rresvport_af(&lport, ai->ai_family);
 119         seteuid(uid);
 120         if (s < 0) {
 121                 if (errno != EAGAIN) {
 122                         if (ai->ai_next) {
 123                                 ai = ai->ai_next;
 124                                 goto retry;
 125                         }
 126                         if (refused && timo <= 16) {
 127                                 sleep(timo);
 128                                 timo *= 2;
 129                                 refused = 0;
 130                                 ai = res;
 131                                 goto retry;
 132                         }
 133                 }
 134                 freeaddrinfo(res);
 135                 return(-1);
 136         }
 137         if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
 138                 err = errno;
 139                 close(s);
 140                 errno = err;
 141                 /*
 142                  * This used to decrement lport, but the current semantics
 143                  * of rresvport do not provide such a function (in fact,
 144                  * rresvport should guarantee that the chosen port will
 145                  * never result in an EADDRINUSE).
 146                  */
 147                 if (errno == EADDRINUSE) {
 148                         goto retry;
 149                 }
 150
 151                 if (errno == ECONNREFUSED)
 152                         refused++;
 153
 154                 if (ai->ai_next != NULL) {
 155                         ai = ai->ai_next;
 156                         goto retry;
 157                 }
 158                 if (refused && timo <= 16) {
 159                         sleep(timo);
 160                         timo *= 2;
 161                         refused = 0;
 162                         ai = res;
 163                         goto retry;
 164                 }
 165                 freeaddrinfo(res);
 166                 return(-1);
 167         }
 168         freeaddrinfo(res);
 169         return(s);
 170 }
 171
 172 /*
 173  * Figure out whether the local machine is the same
 174  * as the remote machine (RM) entry (if it exists).
 175  * We do this by counting the intersection of our
 176  * address list and theirs.  This is better than the
 177  * old method (comparing the canonical names), as it
 178  * allows load-sharing between multiple print servers.
 179  * The return value is an error message which must be
 180  * free()d.
 181  */
 182 char *
 183 checkremote(struct printer *pp)
 184 {
 185         char lclhost[MAXHOSTNAMELEN];
 186         struct addrinfo hints, *local_res, *remote_res, *lr, *rr;
 187         char *err;
 188         int ncommonaddrs, error;
 189         char h1[NI_MAXHOST], h2[NI_MAXHOST];
 190
 191         if (!pp->rp_matches_local) { /* Remote printer doesn't match local */
 192                 pp->remote = 1;
 193                 return NULL;
 194         }
 195
 196         pp->remote = 0; /* assume printer is local */
 197         if (pp->remote_host == NULL)
 198                 return NULL;
 199
 200         /* get the addresses of the local host */
 201         gethostname(lclhost, sizeof(lclhost));
 202         lclhost[sizeof(lclhost) - 1] = '\0';
 203
 204         memset(&hints, 0, sizeof(hints));
 205         hints.ai_family = family;
 206         hints.ai_socktype = SOCK_STREAM;
 207         hints.ai_flags = AI_PASSIVE;
 208         if ((error = getaddrinfo(lclhost, NULL, &hints, &local_res)) != 0) {
 209                 asprintf(&err, "unable to get official name "
 210                          "for local machine %s: %s",
 211                          lclhost, gai_strerror(error));
 212                 return err;
 213         }
 214
 215         /* get the official name of RM */
 216         memset(&hints, 0, sizeof(hints));
 217         hints.ai_family = family;
 218         hints.ai_socktype = SOCK_STREAM;
 219         hints.ai_flags = AI_PASSIVE;
 220         if ((error = getaddrinfo(pp->remote_host, NULL,
 221                                  &hints, &remote_res)) != 0) {
 222                 asprintf(&err, "unable to get address list for "
 223                          "remote machine %s: %s",
 224                          pp->remote_host, gai_strerror(error));
 225                 freeaddrinfo(local_res);
 226                 return err;
 227         }
 228
 229         ncommonaddrs = 0;
 230         for (lr = local_res; lr; lr = lr->ai_next) {
 231                 h1[0] = '\0';
 232                 if (getnameinfo(lr->ai_addr, lr->ai_addrlen, h1, sizeof(h1),
 233                                 NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID) != 0)
 234                         continue;
 235                 for (rr = remote_res; rr; rr = rr->ai_next) {
 236                         h2[0] = '\0';
 237                         if (getnameinfo(rr->ai_addr, rr->ai_addrlen,
 238                                         h2, sizeof(h2), NULL, 0,
 239                                         NI_NUMERICHOST | NI_WITHSCOPEID) != 0)
 240                                 continue;
 241                         if (strcmp(h1, h2) == 0)
 242                                 ncommonaddrs++;
 243                 }
 244         }
 245
 246         /*
 247          * if the two hosts do not share at least one IP address
 248          * then the printer must be remote.
 249          */
 250         if (ncommonaddrs == 0)
 251                 pp->remote = 1;
 252         freeaddrinfo(local_res);
 253         freeaddrinfo(remote_res);
 254         return NULL;
 255 }
 256
 257 /*
 258  * This isn't really network-related, but it's used here to write
 259  * multi-part strings onto sockets without using stdio.  Return
 260  * values are as for writev(2).
 261  */
 262 ssize_t
 263 writel(int strm, ...)
 264 {
 265         va_list ap;
 266         int i, n;
 267         const char *cp;
 268 #define NIOV 12
 269         struct iovec iov[NIOV], *iovp = iov;
 270         ssize_t retval;
 271
 272         /* first count them */
 273         va_start(ap, strm);
 274         n = 0;
 275         do {
 276                 cp = va_arg(ap, char *);
 277                 n++;
 278         } while (cp);
 279         va_end(ap);
 280         n--;                    /* correct for count of trailing null */
 281
 282         if (n > NIOV) {
 283                 iovp = malloc(n * sizeof *iovp);
 284                 if (iovp == 0)
 285                         return -1;
 286         }
 287
 288         /* now make up iovec and send */
 289         va_start(ap, strm);
 290         for (i = 0; i < n; i++) {
 291                 iovp[i].iov_base = va_arg(ap, char *);
 292                 iovp[i].iov_len = strlen(iovp[i].iov_base);
 293         }
 294         va_end(ap);
 295         retval = writev(strm, iovp, n);
 296         if (iovp != iov)
 297                 free(iovp);
 298         return retval;
 299 }