mdw@git.distorted.org.uk Git - tripe/blob - pkstream.c

   1 /* -*-c-*-
   2  *
   3  * $Id: pkstream.c,v 1.2 2003/11/29 23:49:32 mdw Exp $
   4  *
   5  * Forwarding UDP packets over a stream
   6  *
   7  * (c) 2003 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Trivial IP Encryption (TrIPE).
  13  *
  14  * TrIPE 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  * TrIPE 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 TrIPE; 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: pkstream.c,v $
  32  * Revision 1.2  2003/11/29 23:49:32  mdw
  33  * Debianization.
  34  *
  35  * Revision 1.1  2003/04/23 12:53:28  mdw
  36  * New pkstream program.
  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/time.h>
  51 #include <sys/types.h>
  52 #include <unistd.h>
  53 #include <fcntl.h>
  54 #include <sys/uio.h>
  55 #include <sys/socket.h>
  56 #include <netinet/in.h>
  57 #include <arpa/inet.h>
  58 #include <netdb.h>
  59
  60 #include <mLib/alloc.h>
  61 #include <mLib/bits.h>
  62 #include <mLib/dstr.h>
  63 #include <mLib/fdflags.h>
  64 #include <mLib/mdwopt.h>
  65 #include <mLib/quis.h>
  66 #include <mLib/report.h>
  67 #include <mLib/sel.h>
  68 #include <mLib/selpk.h>
  69
  70 /*----- Data structures ---------------------------------------------------*/
  71
  72 typedef struct pk {
  73   struct pk *next;                      /* Next packet in the chain */
  74   octet *p, *o;                         /* Buffer start and current posn */
  75   size_t n;                             /* Size of packet remaining */
  76 } pk;
  77
  78 typedef struct pkstream {
  79   unsigned f;                           /* Flags... */
  80 #define PKF_FULL 1u                     /*   Buffer is full: stop reading */
  81   sel_file r, w;                        /* Read and write selectors */
  82   pk *pks, **pk_tail;                   /* Packet queue */
  83   size_t npk, szpk;                     /* Number and size of data */
  84   selpk p;                              /* Packet parser */
  85 } pkstream;
  86
  87 typedef struct connwait {
  88   sel_file a;                           /* Selector */
  89   struct sockaddr_in me;                /* Who I'm meant to be */
  90   struct in_addr peer;                  /* Who my peer is */
  91 } connwait;
  92
  93 /*----- Static variables --------------------------------------------------*/
  94
  95 static sel_state sel;
  96 static connwait cw;
  97 static int fd_udp;
  98 static size_t pk_nmax = 128, pk_szmax = 1024 * 1024;
  99
 100 /*----- Main code ---------------------------------------------------------*/
 101
 102 static int nonblockify(int fd)
 103 {
 104   return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0));
 105 }
 106
 107 static int cloexec(int fd)
 108 {
 109   return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC));
 110 }
 111
 112 static void dolisten(void);
 113
 114 static void doclose(pkstream *p)
 115 {
 116   pk *pk, *ppk;
 117   close(p->w.fd);
 118   close(p->p.reader.fd);
 119   selpk_destroy(&p->p);
 120   if (!(p->f & PKF_FULL))
 121     sel_rmfile(&p->r);
 122   if (p->npk)
 123     sel_rmfile(&p->w);
 124   for (pk = p->pks; pk; pk = ppk) {
 125     ppk = pk->next;
 126     xfree(pk->p);
 127     xfree(pk);
 128   }
 129   xfree(p);
 130   if (cw.me.sin_port != 0)
 131     dolisten();
 132   else
 133     exit(0);
 134 }
 135
 136 static void rdtcp(octet *b, size_t sz, pkbuf *pk, size_t *k, void *vp)
 137 {
 138   pkstream *p = vp;
 139   size_t pksz;
 140
 141   if (!sz) {
 142     doclose(p);
 143     return;
 144   }
 145   pksz = LOAD16(b);
 146   if (pksz + 2 == sz) {
 147     write(fd_udp, b + 2, pksz);
 148     selpk_want(&p->p, 2);
 149   } else {
 150     selpk_want(&p->p, pksz + 2);
 151     *k = sz;
 152   }
 153 }
 154
 155 static void wrtcp(int fd, unsigned mode, void *vp)
 156 {
 157 #define NPK 16
 158   struct iovec iov[NPK];
 159   pkstream *p = vp;
 160   size_t i;
 161   ssize_t n;
 162   pk *pk, *ppk;
 163
 164   for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) {
 165     iov[i].iov_base = pk->o;
 166     iov[i].iov_len = pk->n;
 167   }
 168
 169   if ((n = writev(fd, iov, i)) < 0) {
 170     if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
 171       return;
 172     moan("couldn't write to TCP socket: %s", strerror(errno));
 173     doclose(p);
 174     return;
 175   }
 176
 177   p->szpk -= n;
 178   for (pk = p->pks; n && pk; pk = ppk) {
 179     ppk = pk->next;
 180     if (pk->n <= n) {
 181       p->npk--;
 182       n -= pk->n;
 183       xfree(pk->p);
 184       xfree(pk);
 185     } else {
 186       pk->n -= n;
 187       pk->o += n;
 188       break;
 189     }
 190   }
 191   p->pks = pk;
 192   if (!pk) {
 193     p->pk_tail = &p->pks;
 194     sel_rmfile(&p->w);
 195   }
 196   if ((p->f & PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax) {
 197     p->f &= ~PKF_FULL;
 198     sel_addfile(&p->r);
 199   }
 200 }
 201
 202 static void rdudp(int fd, unsigned mode, void *vp)
 203 {
 204   octet buf[65536];
 205   ssize_t n;
 206   pkstream *p = vp;
 207   pk *pk;
 208
 209   if ((n = read(fd, buf, sizeof(buf))) < 0) {
 210     if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
 211       return;
 212     moan("couldn't read from UDP socket: %s", strerror(errno));
 213     return;
 214   }
 215   pk = xmalloc(sizeof(*pk));
 216   pk->next = 0;
 217   pk->p = xmalloc(n + 2);
 218   STORE16(pk->p, n);
 219   memcpy(pk->p + 2, buf, n);
 220   pk->o = pk->p;
 221   pk->n = n + 2;
 222   *p->pk_tail = pk;
 223   p->pk_tail = &pk->next;
 224   if (!p->npk)
 225     sel_addfile(&p->w);
 226   sel_force(&p->w);
 227   p->npk++;
 228   p->szpk += n + 2;
 229   if (p->npk >= pk_nmax || p->szpk >= pk_szmax) {
 230     sel_rmfile(&p->r);
 231     p->f |= PKF_FULL;
 232   }
 233 }
 234
 235 static void dofwd(int fd_in, int fd_out)
 236 {
 237   pkstream *p = xmalloc(sizeof(*p));
 238   sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p);
 239   sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p);
 240   selpk_init(&p->p, &sel, fd_in, rdtcp, p);
 241   selpk_want(&p->p, 2);
 242   p->pks = 0;
 243   p->pk_tail = &p->pks;
 244   p->npk = p->szpk = 0;
 245   p->f = 0;
 246   sel_addfile(&p->r);
 247 }
 248
 249 static void doaccept(int fd_s, unsigned mode, void *p)
 250 {
 251   int fd;
 252   struct sockaddr_in sin;
 253   socklen_t sz = sizeof(sin);
 254
 255   if ((fd = accept(fd_s, (struct sockaddr *)&sin, &sz)) < 0) {
 256     if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
 257       return;
 258     moan("couldn't accept incoming connection: %s", strerror(errno));
 259     return;
 260   }
 261   if (cw.peer.s_addr != INADDR_ANY &&
 262       cw.peer.s_addr != sin.sin_addr.s_addr) {
 263     close(fd);
 264     moan("rejecting connection from %s", inet_ntoa(sin.sin_addr));
 265     return;
 266   }
 267   if (nonblockify(fd) || cloexec(fd)) {
 268     close(fd);
 269     moan("couldn't accept incoming connection: %s", strerror(errno));
 270     return;
 271   }
 272   dofwd(fd, fd);
 273   close(fd_s);
 274   sel_rmfile(&cw.a);
 275 }
 276
 277 static void dolisten(void)
 278 {
 279   int fd;
 280   int opt = 1;
 281
 282   if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ||
 283       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) ||
 284       bind(fd, (struct sockaddr *)&cw.me, sizeof(cw.me)) ||
 285       listen(fd, 1) || nonblockify(fd) || cloexec(fd))
 286     die(1, "couldn't set up listening socket: %s", strerror(errno));
 287   sel_initfile(&sel, &cw.a, fd, SEL_READ, doaccept, 0);
 288   sel_addfile(&cw.a);
 289 }
 290
 291 static void parseaddr(const char *pp, struct in_addr *a, unsigned short *pt)
 292 {
 293   char *p = xstrdup(pp);
 294   char *q = 0;
 295   if (a && pt) {
 296     strtok(p, ":");
 297     q = strtok(0, "");
 298     if (!q)
 299       die(1, "missing port number in address `%s'", p);
 300   } else if (pt) {
 301     q = p;
 302   }
 303
 304   if (a) {
 305     struct hostent *h;
 306     if ((h = gethostbyname(p)) == 0)
 307       die(1, "unknown host `%s'", p);
 308     memcpy(a, h->h_addr, sizeof(*a));
 309   }
 310
 311   if (pt) {
 312     struct servent *s;
 313     char *qq;
 314     unsigned long n;
 315     if ((s = getservbyname(q, "tcp")) != 0)
 316       *pt = s->s_port;
 317     else if ((n = strtoul(q, &qq, 0)) == 0 || *qq || n > 0xffff)
 318       die(1, "bad port number `%s'", q);
 319     else
 320       *pt = htons(n);
 321   }
 322 }
 323
 324 static void usage(FILE *fp)
 325 {
 326   pquis(fp,
 327         "Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
 328         ADDR:PORT ADDR:PORT\n");
 329 }
 330
 331 static void version(FILE *fp)
 332 {
 333   pquis(fp, "$, tripe version " VERSION "\n");
 334 }
 335
 336 static void help(FILE *fp)
 337 {
 338   version(fp);
 339   fputc('\n', fp);
 340   usage(fp);
 341   fputs("\n\
 342 Options:\n\
 343 \n\
 344 -h, --help              Display this help text.\n\
 345 -v, --version           Display version number.\n\
 346 -u, --usage             Display pointless usage message.\n\
 347 \n\
 348 -l, --listen=PORT       Listen for connections to TCP PORT.\n\
 349 -p, --peer=ADDR         Only accept connections from IP ADDR.\n\
 350 -b, --bind=ADDR         Bind to ADDR before connecting.\n\
 351 -c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
 352 \n\
 353 Forwards UDP packets over a reliable stream.  By default, uses stdin and\n\
 354 stdout; though it can use TCP sockets instead.\n\
 355 ", fp);
 356 }
 357
 358 int main(int argc, char *argv[])
 359 {
 360   unsigned f = 0;
 361   unsigned short pt;
 362   struct sockaddr_in connaddr, bindaddr;
 363   struct sockaddr_in udp_me, udp_peer;
 364   int len = 65536;
 365
 366 #define f_bogus 1u
 367
 368   ego(argv[0]);
 369   bindaddr.sin_family = AF_INET;
 370   bindaddr.sin_addr.s_addr = INADDR_ANY;
 371   bindaddr.sin_port = 0;
 372   connaddr.sin_family = AF_INET;
 373   connaddr.sin_addr.s_addr = INADDR_ANY;
 374   cw.me.sin_family = AF_INET;
 375   cw.me.sin_addr.s_addr = INADDR_ANY;
 376   cw.me.sin_port = 0;
 377   cw.peer.s_addr = INADDR_ANY;
 378   sel_init(&sel);
 379   for (;;) {
 380     static struct option opt[] = {
 381       { "help",                 0,              0,      'h' },
 382       { "version",              0,              0,      'v' },
 383       { "usage",                0,              0,      'u' },
 384       { "listen",               OPTF_ARGREQ,    0,      'l' },
 385       { "peer",                 OPTF_ARGREQ,    0,      'p' },
 386       { "bind",                 OPTF_ARGREQ,    0,      'b' },
 387       { "connect",              OPTF_ARGREQ,    0,      'c' },
 388       { 0,                      0,              0,      0 }
 389     };
 390     int i;
 391
 392     i = mdwopt(argc, argv, "hvul:p:b:c:", opt, 0, 0, 0);
 393     if (i < 0)
 394       break;
 395     switch (i) {
 396       case 'h':
 397         help(stdout);
 398         exit(0);
 399       case 'v':
 400         version(stdout);
 401         exit(0);
 402       case 'u':
 403         usage(stdout);
 404         exit(0);
 405       case 'l':
 406         parseaddr(optarg, 0, &pt);
 407         cw.me.sin_port = pt;
 408         break;
 409       case 'p':
 410         parseaddr(optarg, &cw.peer, 0);
 411         break;
 412       case 'b':
 413         parseaddr(optarg, &bindaddr.sin_addr, 0);
 414         break;
 415       case 'c':
 416         parseaddr(optarg, &connaddr.sin_addr, &pt);
 417         connaddr.sin_port = pt;
 418         break;
 419       default:
 420         f |= f_bogus;
 421         break;
 422     }
 423   }
 424   if (optind + 2 != argc || (f & f_bogus)) {
 425     usage(stderr);
 426     exit(1);
 427   }
 428
 429   udp_me.sin_family = udp_peer.sin_family = AF_INET;
 430   parseaddr(argv[optind], &udp_me.sin_addr, &pt);
 431   udp_me.sin_port = pt;
 432   parseaddr(argv[optind + 1], &udp_peer.sin_addr, &pt);
 433   udp_peer.sin_port = pt;
 434
 435   if ((fd_udp = socket(PF_INET, SOCK_DGRAM, 0)) < 0 ||
 436       bind(fd_udp, (struct sockaddr *)&udp_me, sizeof(udp_me)) ||
 437       connect(fd_udp, (struct sockaddr *)&udp_peer, sizeof(udp_peer)) ||
 438       setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
 439       setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) ||
 440       nonblockify(fd_udp) || cloexec(fd_udp))
 441     die(1, "couldn't set up UDP socket: %s", strerror(errno));
 442
 443   if (cw.me.sin_port != 0)
 444     dolisten();
 445   else if (connaddr.sin_addr.s_addr != INADDR_ANY) {
 446     int fd;
 447     if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ||
 448         bind(fd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) ||
 449         connect(fd, (struct sockaddr *)&connaddr, sizeof(connaddr)) ||
 450         nonblockify(fd) || cloexec(fd))
 451       die(1, "couldn't connect to TCP server: %s", strerror(errno));
 452     dofwd(fd, fd);
 453   } else
 454     dofwd(STDIN_FILENO, STDOUT_FILENO);
 455
 456   for (;;)
 457     sel_select(&sel);
 458   return (0);
 459 }
 460
 461 /*----- That's all, folks -------------------------------------------------*/