mdw@git.distorted.org.uk Git - fwd/blob - inet.c

   1 /* -*-c-*-
   2  *
   3  * $Id: inet.c,v 1.2 1999/07/27 18:30:53 mdw Exp $
   4  *
   5  * Protocol specific definitions for IPv4 sockets
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: inet.c,v $
  32  * Revision 1.2  1999/07/27 18:30:53  mdw
  33  * Various minor portability fixes.
  34  *
  35  * Revision 1.1  1999/07/26 23:34:11  mdw
  36  * New socket address types.
  37  *
  38  */
  39
  40 /*----- Header files ------------------------------------------------------*/
  41
  42 #include "config.h"
  43
  44 #include <ctype.h>
  45 #include <errno.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49
  50 #include <sys/types.h>
  51 #include <unistd.h>
  52
  53 #include <sys/socket.h>
  54 #include <netinet/in.h>
  55 #include <arpa/inet.h>
  56 #include <netdb.h>
  57
  58 #include <mLib/alloc.h>
  59 #include <mLib/dstr.h>
  60 #include <mLib/report.h>
  61 #include <mLib/sub.h>
  62
  63 #include "acl.h"
  64 #include "addr.h"
  65 #include "conf.h"
  66 #include "identify.h"
  67 #include "inet.h"
  68 #include "reffd.h"
  69 #include "scan.h"
  70
  71 /*----- Data structures ---------------------------------------------------*/
  72
  73 typedef struct inet_addrx {
  74   addr a;
  75   struct sockaddr_in sin;
  76 } inet_addrx;
  77
  78 typedef struct inet_opts {
  79   addr_opts ao;
  80   acl_entry *acl;
  81   acl_entry **acltail;
  82 } inet_opts;
  83
  84 /*----- Protocol operations -----------------------------------------------*/
  85
  86 /* --- @read@ --- */
  87
  88 static addr *inet_read(scanner *sc, unsigned type)
  89 {
  90   inet_addrx *ia = xmalloc(sizeof(*ia));
  91
  92   ia->a.ops = &inet_ops;
  93   ia->a.sz = sizeof(struct sockaddr_in);
  94   memset(&ia->sin, 0, sizeof(ia->sin));
  95   ia->sin.sin_family = AF_INET;
  96
  97   /* --- Read the host address part --- */
  98
  99   switch (type) {
 100     case ADDR_SRC:
 101       if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "port") == 0)
 102         token(sc);
 103       ia->sin.sin_addr.s_addr = htonl(INADDR_ANY);
 104       break;
 105     case ADDR_DEST: {
 106       struct hostent *h;
 107       dstr d = DSTR_INIT;
 108       conf_name(sc, '.', &d);
 109       if ((h = gethostbyname(d.buf)) == 0)
 110         error(sc, "couldn't resolve Internet address `%s'", d.buf);
 111       memcpy(&ia->sin.sin_addr, h->h_addr, sizeof(struct in_addr));
 112       dstr_destroy(&d);
 113       if (sc->t == ':')
 114         token(sc);
 115     } break;
 116   }
 117
 118   /* --- Read the port number --- */
 119
 120   {
 121     struct servent *s;
 122
 123     if (sc->t != CTOK_WORD)
 124       error(sc, "parse error, TCP port expected");
 125     if (isdigit((unsigned char)sc->d.buf[0]))
 126       ia->sin.sin_port = htons(atoi(sc->d.buf));
 127     else if ((s = getservbyname(sc->d.buf, "tcp")) == 0)
 128       error(sc, "unknown tcp service `%s'", sc->d.buf);
 129     else
 130       ia->sin.sin_port = s->s_port;
 131     token(sc);
 132   }
 133
 134   return (&ia->a);
 135 }
 136
 137 /* --- @destroy@ --- */
 138
 139 static void inet_destroy(addr *a)
 140 {
 141   inet_addrx *ia = (inet_addrx *)a;
 142   DESTROY(ia);
 143 }
 144
 145 /* --- @print@ --- */
 146
 147 static void inet_print(addr *a, unsigned type, dstr *d)
 148 {
 149   inet_addrx *ia = (inet_addrx *)a;
 150   switch (type) {
 151     case ADDR_SRC:
 152       dstr_putf(d, "inet:%u", (unsigned)ntohs(ia->sin.sin_port));
 153       break;
 154     case ADDR_DEST:
 155       dstr_putf(d, "inet:%s:%u",
 156                 inet_ntoa(ia->sin.sin_addr),
 157                 (unsigned)ntohs(ia->sin.sin_port));
 158       break;
 159   }
 160 }
 161
 162 /* --- @initopts@ --- */
 163
 164 static addr_opts *inet_initopts(void)
 165 {
 166   inet_opts *io = CREATE(inet_opts);
 167   io->acl = 0;
 168   io->acltail = &io->acl;
 169   return (&io->ao);
 170 }
 171
 172 /* --- @option@ --- */
 173
 174 static int inet_option(scanner *sc, addr_opts *ao)
 175 {
 176   inet_opts *io = (inet_opts *)ao;
 177
 178   CONF_BEGIN(sc, "inet", "Internet socket")
 179
 180   unsigned act;
 181
 182   /* --- Access control limitations --- */
 183
 184   if ((strcmp(sc->d.buf, "allow") == 0 && (act = ACL_ALLOW, 1)) ||
 185        (strcmp(sc->d.buf, "deny") == 0 && (act = ACL_DENY, 1))) {
 186     struct hostent *h;
 187     struct netent *n;
 188     struct in_addr a, m;
 189     dstr d = DSTR_INIT;
 190
 191     /* --- Find the host or network address --- */
 192
 193     token(sc);
 194     if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "from") == 0)
 195       token(sc);
 196     conf_name(sc, '.', &d);
 197     if ((n = getnetbyname(d.buf)) != 0)
 198       a.s_addr = htonl(n->n_net);
 199     else if ((h = gethostbyname(d.buf)) == 0)
 200       error(sc, "couldn't resolve address `%s'", d.buf);
 201     else
 202       memcpy(&a, h->h_addr, sizeof(struct in_addr));
 203
 204     /* --- Find the netmask, if any --- */
 205
 206     if (sc->t != '/')
 207       m.s_addr = ~0ul;
 208     else {
 209       token(sc);
 210       DRESET(&d);
 211       conf_name(sc, '.', &d);
 212       if (strchr(d.buf, '.') == 0) {
 213         int n = atoi(d.buf);
 214         if (n == 0)
 215           m.s_addr = 0;
 216         else
 217           m.s_addr = htonl((~0ul << (32 - n)) & 0xffffffff);
 218       } else {
 219 #ifdef HAVE_INET_ATON
 220         if (!inet_aton(d.buf, &m))
 221           error(sc, "bad netmask `%s'", d.buf);
 222 #else
 223         m.s_addr = inet_addr(d.buf);
 224 #endif
 225       }
 226     }
 227     dstr_destroy(&d);
 228
 229     /* --- Add the access control entry --- */
 230
 231     acl_add(io ? &io->acltail : 0, act, a, m);
 232     CONF_ACCEPT;
 233   }
 234
 235   /* --- Anything unrecognized --- */
 236
 237   CONF_END;
 238 }
 239
 240 /* --- @accept@ --- */
 241
 242 static reffd *inet_accept(int fd, addr_opts *ao, const char *desc)
 243 {
 244   inet_opts *io = (inet_opts *)ao;
 245   int nfd;
 246   id_req q;
 247   int lsinsz = sizeof(q.lsin), rsinsz = sizeof(q.rsin);
 248
 249   /* --- Accept the new connection --- */
 250
 251   if ((nfd = accept(fd, (struct sockaddr *)&q.rsin, &rsinsz)) < 0)
 252     return (0);
 253   if (getsockname(nfd, (struct sockaddr *)&q.lsin, &lsinsz)) {
 254     close(nfd);
 255     return (0);
 256   }
 257   q.desc = desc;
 258   q.r = reffd_init(nfd);
 259
 260   /* --- Find out whether this connection is allowed --- */
 261
 262   if (!acl_check(io->acl, q.rsin.sin_addr)) {
 263     q.act = "refused";
 264     if (!(io->ao.f & ADDRF_NOLOG))
 265       identify(&q);
 266     REFFD_DEC(q.r);
 267     return (0);
 268   }
 269
 270   /* --- Everything seems to be OK --- */
 271
 272   q.act = "accepted";
 273   if (!(io->ao.f & ADDRF_NOLOG))
 274     identify(&q);
 275   return (q.r);
 276 }
 277
 278 /* --- @freeopts@ --- */
 279
 280 static void inet_freeopts(addr_opts *ao)
 281 {
 282   inet_opts *io = (inet_opts *)ao;
 283   acl_free(io->acl);
 284   DESTROY(ao);
 285 }
 286
 287 /* --- Ops table --- */
 288
 289 addr_ops inet_ops = {
 290   "inet", PF_INET,
 291   inet_read, inet_destroy, inet_print,
 292   inet_initopts, inet_option, inet_accept, inet_freeopts, 0, 0
 293 };
 294
 295 /*----- That's all, folks -------------------------------------------------*/