[tripe] / pkstream / pkstream.c

/* -*-c-*-
 *
 * Forwarding UDP packets over a stream
 *
 * (c) 2003 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Trivial IP Encryption (TrIPE).
 *
 * TrIPE is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * TrIPE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with TrIPE; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include "config.h"

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <mLib/alloc.h>
#include <mLib/bits.h>
#include <mLib/dstr.h>
#include <mLib/fdflags.h>
#include <mLib/mdwopt.h>
#include <mLib/quis.h>
#include <mLib/report.h>
#include <mLib/sel.h>
#include <mLib/selpk.h>

/*----- Data structures ---------------------------------------------------*/

typedef struct pk {
  struct pk *next;			/* Next packet in the chain */
  octet *p, *o;				/* Buffer start and current posn */
  size_t n;				/* Size of packet remaining */
} pk;

typedef struct pkstream {
  unsigned f;				/* Flags... */
#define PKF_FULL 1u			/*   Buffer is full: stop reading */
  sel_file r, w;			/* Read and write selectors */
  pk *pks, **pk_tail;			/* Packet queue */
  size_t npk, szpk;			/* Number and size of data */
  selpk p;				/* Packet parser */
} pkstream;

typedef struct connwait {
  sel_file a;				/* Selector */
  struct sockaddr_in me;		/* Who I'm meant to be */
  struct in_addr peer;			/* Who my peer is */
} connwait;

/*----- Static variables --------------------------------------------------*/

static sel_state sel;
static connwait cw;
static int fd_udp;
static size_t pk_nmax = 128, pk_szmax = 1024 * 1024;

/*----- Main code ---------------------------------------------------------*/

static int nonblockify(int fd)
  { return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)); }

static int cloexec(int fd)
  { return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC)); }

static void dolisten(void);

static void doclose(pkstream *p)
{
  pk *pk, *ppk;
  close(p->w.fd);
  close(p->p.reader.fd);
  selpk_destroy(&p->p);
  if (!(p->f & PKF_FULL))
    sel_rmfile(&p->r);
  if (p->npk)
    sel_rmfile(&p->w);
  for (pk = p->pks; pk; pk = ppk) {
    ppk = pk->next;
    xfree(pk->p);
    xfree(pk);
  }
  xfree(p);
  if (cw.me.sin_port != 0)
    dolisten();
  else
    exit(0);
}

static void rdtcp(octet *b, size_t sz, pkbuf *pk, size_t *k, void *vp)
{
  pkstream *p = vp;
  size_t pksz;
  int hunoz;

  if (!sz) {
    doclose(p);
    return;
  }
  pksz = LOAD16(b);
  if (pksz + 2 == sz) {
    hunoz = write(fd_udp, b + 2, pksz);
    selpk_want(&p->p, 2);
  } else {
    selpk_want(&p->p, pksz + 2);
    *k = sz;
  }
}

static void wrtcp(int fd, unsigned mode, void *vp)
{
#define NPK 16
  struct iovec iov[NPK];
  pkstream *p = vp;
  size_t i;
  ssize_t n;
  pk *pk, *ppk;

  for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) {
    iov[i].iov_base = pk->o;
    iov[i].iov_len = pk->n;
  }

  if ((n = writev(fd, iov, i)) < 0) {
    if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
      return;
    moan("couldn't write to TCP socket: %s", strerror(errno));
    doclose(p);
    return;
  }

  p->szpk -= n;
  for (pk = p->pks; n && pk; pk = ppk) {
    ppk = pk->next;
    if (pk->n <= n) {
      p->npk--;
      n -= pk->n;
      xfree(pk->p);
      xfree(pk);
    } else {
      pk->n -= n;
      pk->o += n;
      break;
    }
  }
  p->pks = pk;
  if (!pk) {
    p->pk_tail = &p->pks;
    sel_rmfile(&p->w);
  }
  if ((p->f & PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax) {
    p->f &= ~PKF_FULL;
    sel_addfile(&p->r);
  }
}

static void rdudp(int fd, unsigned mode, void *vp)
{
  octet buf[65536];
  ssize_t n;
  pkstream *p = vp;
  pk *pk;

  if ((n = read(fd, buf, sizeof(buf))) < 0) {
    if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
      return;
    moan("couldn't read from UDP socket: %s", strerror(errno));
    return;
  }
  pk = xmalloc(sizeof(*pk));
  pk->next = 0;
  pk->p = xmalloc(n + 2);
  STORE16(pk->p, n);
  memcpy(pk->p + 2, buf, n);
  pk->o = pk->p;
  pk->n = n + 2;
  *p->pk_tail = pk;
  p->pk_tail = &pk->next;
  if (!p->npk)
    sel_addfile(&p->w);
  sel_force(&p->w);
  p->npk++;
  p->szpk += n + 2;
  if (p->npk >= pk_nmax || p->szpk >= pk_szmax) {
    sel_rmfile(&p->r);
    p->f |= PKF_FULL;
  }
}

static void dofwd(int fd_in, int fd_out)
{
  pkstream *p = xmalloc(sizeof(*p));
  sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p);
  sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p);
  selpk_init(&p->p, &sel, fd_in, rdtcp, p);
  selpk_want(&p->p, 2);
  p->pks = 0;
  p->pk_tail = &p->pks;
  p->npk = p->szpk = 0;
  p->f = 0;
  sel_addfile(&p->r);
}

static void doaccept(int fd_s, unsigned mode, void *p)
{
  int fd;
  struct sockaddr_in sin;
  socklen_t sz = sizeof(sin);

  if ((fd = accept(fd_s, (struct sockaddr *)&sin, &sz)) < 0) {
    if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
      return;
    moan("couldn't accept incoming connection: %s", strerror(errno));
    return;
  }
  if (cw.peer.s_addr != INADDR_ANY &&
      cw.peer.s_addr != sin.sin_addr.s_addr) {
    close(fd);
    moan("rejecting connection from %s", inet_ntoa(sin.sin_addr));
    return;
  }
  if (nonblockify(fd) || cloexec(fd)) {
    close(fd);
    moan("couldn't accept incoming connection: %s", strerror(errno));
    return;
  }
  dofwd(fd, fd);
  close(fd_s);
  sel_rmfile(&cw.a);
}

static void dolisten(void)
{
  int fd;
  int opt = 1;

  if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ||
      setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) ||
      bind(fd, (struct sockaddr *)&cw.me, sizeof(cw.me)) ||
      listen(fd, 1) || nonblockify(fd) || cloexec(fd))
    die(1, "couldn't set up listening socket: %s", strerror(errno));
  sel_initfile(&sel, &cw.a, fd, SEL_READ, doaccept, 0);
  sel_addfile(&cw.a);
}

static void parseaddr(const char *pp, struct in_addr *a, unsigned short *pt)
{
  char *p = xstrdup(pp);
  char *q = 0;
  if (a && pt) {
    strtok(p, ":");
    q = strtok(0, "");
    if (!q)
      die(1, "missing port number in address `%s'", p);
  } else if (pt) {
    q = p;
  }

  if (a) {
    struct hostent *h;
    if ((h = gethostbyname(p)) == 0)
      die(1, "unknown host `%s'", p);
    memcpy(a, h->h_addr, sizeof(*a));
  }

  if (pt) {
    struct servent *s;
    char *qq;
    unsigned long n;
    if ((s = getservbyname(q, "tcp")) != 0)
      *pt = s->s_port;
    else if ((n = strtoul(q, &qq, 0)) == 0 || *qq || n > 0xffff)
      die(1, "bad port number `%s'", q);
    else
      *pt = htons(n);
  }
}

static void usage(FILE *fp)
{
  pquis(fp,
	"Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
	ADDR:PORT ADDR:PORT\n");
}

static void version(FILE *fp)
  { pquis(fp, "$, tripe version " VERSION "\n"); }

static void help(FILE *fp)
{
  version(fp);
  fputc('\n', fp);
  usage(fp);
  fputs("\n\
Options:\n\
\n\
-h, --help		Display this help text.\n\
-v, --version		Display version number.\n\
-u, --usage		Display pointless usage message.\n\
\n\
-l, --listen=PORT	Listen for connections to TCP PORT.\n\
-p, --peer=ADDR		Only accept connections from IP ADDR.\n\
-b, --bind=ADDR		Bind to ADDR before connecting.\n\
-c, --connect=ADDR:PORT	Connect to IP ADDR, TCP PORT.\n\
\n\
Forwards UDP packets over a reliable stream.  By default, uses stdin and\n\
stdout; though it can use TCP sockets instead.\n\
", fp);
}

int main(int argc, char *argv[])
{
  unsigned f = 0;
  unsigned short pt;
  struct sockaddr_in connaddr, bindaddr;
  struct sockaddr_in udp_me, udp_peer;
  int len = 65536;

#define f_bogus 1u

  ego(argv[0]);
  bindaddr.sin_family = AF_INET;
  bindaddr.sin_addr.s_addr = INADDR_ANY;
  bindaddr.sin_port = 0;
  connaddr.sin_family = AF_INET;
  connaddr.sin_addr.s_addr = INADDR_ANY;
  cw.me.sin_family = AF_INET;
  cw.me.sin_addr.s_addr = INADDR_ANY;
  cw.me.sin_port = 0;
  cw.peer.s_addr = INADDR_ANY;
  sel_init(&sel);
  for (;;) {
    static struct option opt[] = {
      { "help",			0,		0,	'h' },
      { "version",		0,		0,	'v' },
      { "usage",		0,		0,	'u' },
      { "listen",		OPTF_ARGREQ,	0,	'l' },
      { "peer",			OPTF_ARGREQ,	0,	'p' },
      { "bind",			OPTF_ARGREQ,	0,	'b' },
      { "connect",		OPTF_ARGREQ,	0,	'c' },
      { 0,			0,		0,	0 }
    };
    int i;

    i = mdwopt(argc, argv, "hvul:p:b:c:", opt, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'h':
	help(stdout);
	exit(0);
      case 'v':
	version(stdout);
	exit(0);
      case 'u':
	usage(stdout);
	exit(0);
      case 'l':
	parseaddr(optarg, 0, &pt);
	cw.me.sin_port = pt;
	break;
      case 'p':
	parseaddr(optarg, &cw.peer, 0);
	break;
      case 'b':
	parseaddr(optarg, &bindaddr.sin_addr, 0);
	break;
      case 'c':
	parseaddr(optarg, &connaddr.sin_addr, &pt);
	connaddr.sin_port = pt;
	break;
      default:
	f |= f_bogus;
	break;
    }
  }
  if (optind + 2 != argc || (f & f_bogus)) {
    usage(stderr);
    exit(1);
  }

  udp_me.sin_family = udp_peer.sin_family = AF_INET;
  parseaddr(argv[optind], &udp_me.sin_addr, &pt);
  udp_me.sin_port = pt;
  parseaddr(argv[optind + 1], &udp_peer.sin_addr, &pt);
  udp_peer.sin_port = pt;

  if ((fd_udp = socket(PF_INET, SOCK_DGRAM, 0)) < 0 ||
      bind(fd_udp, (struct sockaddr *)&udp_me, sizeof(udp_me)) ||
      connect(fd_udp, (struct sockaddr *)&udp_peer, sizeof(udp_peer)) ||
      setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
      setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) ||
      nonblockify(fd_udp) || cloexec(fd_udp))
    die(1, "couldn't set up UDP socket: %s", strerror(errno));

  if (cw.me.sin_port != 0)
    dolisten();
  else if (connaddr.sin_addr.s_addr != INADDR_ANY) {
    int fd;
    if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ||
	bind(fd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) ||
	connect(fd, (struct sockaddr *)&connaddr, sizeof(connaddr)) ||
	nonblockify(fd) || cloexec(fd))
      die(1, "couldn't connect to TCP server: %s", strerror(errno));
    dofwd(fd, fd);
  } else
    dofwd(STDIN_FILENO, STDOUT_FILENO);

  for (;;)
    sel_select(&sel);
  return (0);
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
07212ba4	1	/* --c--
07212ba4	2	*
	3	* Forwarding UDP packets over a stream
	4	*
	5	* (c) 2003 Straylight/Edgeware
	6	*/
	7
e04c2d50	8	/----- Licensing notice --------------------------------------------------
07212ba4	9	*
	10	* This file is part of Trivial IP Encryption (TrIPE).
	11	*
	12	* TrIPE is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License as published by
	14	* the Free Software Foundation; either version 2 of the License, or
	15	* (at your option) any later version.
e04c2d50	16	*
07212ba4	17	* TrIPE is distributed in the hope that it will be useful,
	18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	20	* GNU General Public License for more details.
e04c2d50	21	*
07212ba4	22	* You should have received a copy of the GNU General Public License
	23	* along with TrIPE; if not, write to the Free Software Foundation,
	24	* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	25	*/
	26
07212ba4	27	/----- Header files ------------------------------------------------------/
	28
	29	#include "config.h"
	30
	31	#include <ctype.h>
	32	#include <errno.h>
	33	#include <stdio.h>
	34	#include <stdlib.h>
	35	#include <string.h>
	36
	37	#include <sys/time.h>
	38	#include <sys/types.h>
	39	#include <unistd.h>
	40	#include <fcntl.h>
	41	#include <sys/uio.h>
	42	#include <sys/socket.h>
	43	#include <netinet/in.h>
	44	#include <arpa/inet.h>
	45	#include <netdb.h>
	46
	47	#include <mLib/alloc.h>
	48	#include <mLib/bits.h>
	49	#include <mLib/dstr.h>
	50	#include <mLib/fdflags.h>
	51	#include <mLib/mdwopt.h>
	52	#include <mLib/quis.h>
	53	#include <mLib/report.h>
	54	#include <mLib/sel.h>
	55	#include <mLib/selpk.h>
	56
	57	/----- Data structures ---------------------------------------------------/
	58
	59	typedef struct pk {
	60	struct pk next; / Next packet in the chain */
	61	octet p, o; /* Buffer start and current posn */
	62	size_t n; /* Size of packet remaining */
	63	} pk;
	64
	65	typedef struct pkstream {
	66	unsigned f; /* Flags... */
	67	#define PKF_FULL 1u /* Buffer is full: stop reading */
	68	sel_file r, w; /* Read and write selectors */
	69	pk pks, pk_tail; / Packet queue */
	70	size_t npk, szpk; /* Number and size of data */
	71	selpk p; /* Packet parser */
	72	} pkstream;
	73
	74	typedef struct connwait {
	75	sel_file a; /* Selector */
	76	struct sockaddr_in me; /* Who I'm meant to be */
	77	struct in_addr peer; /* Who my peer is */
	78	} connwait;
	79
	80	/----- Static variables --------------------------------------------------/
	81
	82	static sel_state sel;
	83	static connwait cw;
	84	static int fd_udp;
	85	static size_t pk_nmax = 128, pk_szmax = 1024 * 1024;
	86
	87	/----- Main code ---------------------------------------------------------/
	88
	89	static int nonblockify(int fd)
f98df549	90	{ return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)); }
07212ba4	91
07212ba4	92	static int cloexec(int fd)
f98df549	93	{ return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC)); }
07212ba4	94
	95	static void dolisten(void);
	96
	97	static void doclose(pkstream *p)
	98	{
	99	pk pk, ppk;
	100	close(p->w.fd);
	101	close(p->p.reader.fd);
	102	selpk_destroy(&p->p);
	103	if (!(p->f & PKF_FULL))
	104	sel_rmfile(&p->r);
	105	if (p->npk)
	106	sel_rmfile(&p->w);
	107	for (pk = p->pks; pk; pk = ppk) {
	108	ppk = pk->next;
	109	xfree(pk->p);
	110	xfree(pk);
	111	}
	112	xfree(p);
	113	if (cw.me.sin_port != 0)
	114	dolisten();
	115	else
	116	exit(0);
	117	}
	118
	119	static void rdtcp(octet b, size_t sz, pkbuf pk, size_t k, void vp)
	120	{
	121	pkstream *p = vp;
	122	size_t pksz;
3fe0fc3a	123	int hunoz;
07212ba4	124
	125	if (!sz) {
	126	doclose(p);
	127	return;
	128	}
	129	pksz = LOAD16(b);
	130	if (pksz + 2 == sz) {
3fe0fc3a	131	hunoz = write(fd_udp, b + 2, pksz);
07212ba4	132	selpk_want(&p->p, 2);
	133	} else {
	134	selpk_want(&p->p, pksz + 2);
	135	*k = sz;
	136	}
	137	}
	138
	139	static void wrtcp(int fd, unsigned mode, void *vp)
	140	{
	141	#define NPK 16
	142	struct iovec iov[NPK];
	143	pkstream *p = vp;
	144	size_t i;
	145	ssize_t n;
	146	pk pk, ppk;
	147
	148	for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) {
	149	iov[i].iov_base = pk->o;
	150	iov[i].iov_len = pk->n;
	151	}
	152
	153	if ((n = writev(fd, iov, i)) < 0) {
	154	if (errno == EAGAIN \|\| errno == EWOULDBLOCK \|\| errno == EINTR)
	155	return;
	156	moan("couldn't write to TCP socket: %s", strerror(errno));
	157	doclose(p);
	158	return;
	159	}
	160
	161	p->szpk -= n;
	162	for (pk = p->pks; n && pk; pk = ppk) {
	163	ppk = pk->next;
	164	if (pk->n <= n) {
	165	p->npk--;
	166	n -= pk->n;
	167	xfree(pk->p);
	168	xfree(pk);
	169	} else {
	170	pk->n -= n;
	171	pk->o += n;
	172	break;
	173	}
	174	}
	175	p->pks = pk;
	176	if (!pk) {
	177	p->pk_tail = &p->pks;
	178	sel_rmfile(&p->w);
	179	}
	180	if ((p->f & PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax) {
	181	p->f &= ~PKF_FULL;
	182	sel_addfile(&p->r);
	183	}
	184	}
	185
	186	static void rdudp(int fd, unsigned mode, void *vp)
	187	{
	188	octet buf[65536];
	189	ssize_t n;
	190	pkstream *p = vp;
	191	pk *pk;
	192
	193	if ((n = read(fd, buf, sizeof(buf))) < 0) {
	194	if (errno == EAGAIN \|\| errno == EWOULDBLOCK \|\| errno == EINTR)
	195	return;
196	moan("couldn't read from UDP socket: %s", strerror(errno));
197	return;
198	}
199	pk = xmalloc(sizeof(*pk));
200	pk->next = 0;
201	pk->p = xmalloc(n + 2);
202	STORE16(pk->p, n);
203	memcpy(pk->p + 2, buf, n);
204	pk->o = pk->p;
205	pk->n = n + 2;
206	*p->pk_tail = pk;
207	p->pk_tail = &pk->next;
208	if (!p->npk)
209	sel_addfile(&p->w);
210	sel_force(&p->w);
211	p->npk++;
212	p->szpk += n + 2;
213	if (p->npk >= pk_nmax \|\| p->szpk >= pk_szmax) {
214	sel_rmfile(&p->r);
215	p->f \|= PKF_FULL;
216	}
217	}
218
219	static void dofwd(int fd_in, int fd_out)
220	{
221	pkstream p = xmalloc(sizeof(p));
222	sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p);
223	sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p);
224	selpk_init(&p->p, &sel, fd_in, rdtcp, p);
225	selpk_want(&p->p, 2);
226	p->pks = 0;
227	p->pk_tail = &p->pks;
228	p->npk = p->szpk = 0;
229	p->f = 0;
230	sel_addfile(&p->r);
231	}
232
233	static void doaccept(int fd_s, unsigned mode, void *p)
234	{
235	int fd;
236	struct sockaddr_in sin;
237	socklen_t sz = sizeof(sin);
238
239	if ((fd = accept(fd_s, (struct sockaddr *)&sin, &sz)) < 0) {
240	if (errno == EAGAIN \|\| errno == EWOULDBLOCK \|\| errno == EINTR)
241	return;
242	moan("couldn't accept incoming connection: %s", strerror(errno));
243	return;
244	}
245	if (cw.peer.s_addr != INADDR_ANY &&
246	cw.peer.s_addr != sin.sin_addr.s_addr) {
247	close(fd);
248	moan("rejecting connection from %s", inet_ntoa(sin.sin_addr));
249	return;
250	}
251	if (nonblockify(fd) \|\| cloexec(fd)) {
252	close(fd);
253	moan("couldn't accept incoming connection: %s", strerror(errno));
254	return;
255	}
256	dofwd(fd, fd);
257	close(fd_s);
258	sel_rmfile(&cw.a);
259	}
260
261	static void dolisten(void)
262	{
263	int fd;
264	int opt = 1;
265
266	if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 \|\|
07212ba4	267	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) \|\|
ef4a1ab7	268	bind(fd, (struct sockaddr *)&cw.me, sizeof(cw.me)) \|\|
07212ba4	269	listen(fd, 1) \|\| nonblockify(fd) \|\| cloexec(fd))
	270	die(1, "couldn't set up listening socket: %s", strerror(errno));
	271	sel_initfile(&sel, &cw.a, fd, SEL_READ, doaccept, 0);
	272	sel_addfile(&cw.a);
	273	}
	274
	275	static void parseaddr(const char pp, struct in_addr a, unsigned short *pt)
	276	{
	277	char *p = xstrdup(pp);
	278	char *q = 0;
	279	if (a && pt) {
	280	strtok(p, ":");
	281	q = strtok(0, "");
	282	if (!q)
	283	die(1, "missing port number in address `%s'", p);
	284	} else if (pt) {
	285	q = p;
	286	}
	287
	288	if (a) {
	289	struct hostent *h;
	290	if ((h = gethostbyname(p)) == 0)
	291	die(1, "unknown host `%s'", p);
	292	memcpy(a, h->h_addr, sizeof(*a));
	293	}
	294
	295	if (pt) {
	296	struct servent *s;
	297	char *qq;
	298	unsigned long n;
	299	if ((s = getservbyname(q, "tcp")) != 0)
	300	*pt = s->s_port;
	301	else if ((n = strtoul(q, &qq, 0)) == 0 \|\| *qq \|\| n > 0xffff)
	302	die(1, "bad port number `%s'", q);
	303	else
	304	*pt = htons(n);
	305	}
	306	}
	307
	308	static void usage(FILE *fp)
	309	{
	310	pquis(fp,
ef4a1ab7	311	"Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
ef4a1ab7	312	ADDR:PORT ADDR:PORT\n");
07212ba4	313	}
	314
	315	static void version(FILE *fp)
f98df549	316	{ pquis(fp, "$, tripe version " VERSION "\n"); }
07212ba4	317
	318	static void help(FILE *fp)
	319	{
	320	version(fp);
	321	fputc('\n', fp);
	322	usage(fp);
	323	fputs("\n\
	324	Options:\n\
	325	\n\
	326	-h, --help Display this help text.\n\
	327	-v, --version Display version number.\n\
	328	-u, --usage Display pointless usage message.\n\
	329	\n\
	330	-l, --listen=PORT Listen for connections to TCP PORT.\n\
ef4a1ab7	331	-p, --peer=ADDR Only accept connections from IP ADDR.\n\
ef4a1ab7	332	-b, --bind=ADDR Bind to ADDR before connecting.\n\
07212ba4	333	-c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
	334	\n\
	335	Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
	336	stdout; though it can use TCP sockets instead.\n\
	337	", fp);
	338	}
	339
	340	int main(int argc, char *argv[])
	341	{
	342	unsigned f = 0;
	343	unsigned short pt;
ef4a1ab7	344	struct sockaddr_in connaddr, bindaddr;
07212ba4	345	struct sockaddr_in udp_me, udp_peer;
	346	int len = 65536;
	347
	348	#define f_bogus 1u
	349
	350	ego(argv[0]);
ef4a1ab7	351	bindaddr.sin_family = AF_INET;
	352	bindaddr.sin_addr.s_addr = INADDR_ANY;
	353	bindaddr.sin_port = 0;
07212ba4	354	connaddr.sin_family = AF_INET;
ef4a1ab7	355	connaddr.sin_addr.s_addr = INADDR_ANY;
07212ba4	356	cw.me.sin_family = AF_INET;
	357	cw.me.sin_addr.s_addr = INADDR_ANY;
	358	cw.me.sin_port = 0;
	359	cw.peer.s_addr = INADDR_ANY;
	360	sel_init(&sel);
	361	for (;;) {
	362	static struct option opt[] = {
	363	{ "help", 0, 0, 'h' },
	364	{ "version", 0, 0, 'v' },
	365	{ "usage", 0, 0, 'u' },
	366	{ "listen", OPTF_ARGREQ, 0, 'l' },
	367	{ "peer", OPTF_ARGREQ, 0, 'p' },
ef4a1ab7	368	{ "bind", OPTF_ARGREQ, 0, 'b' },
07212ba4	369	{ "connect", OPTF_ARGREQ, 0, 'c' },
	370	{ 0, 0, 0, 0 }
	371	};
	372	int i;
	373
ef4a1ab7	374	i = mdwopt(argc, argv, "hvul:p:b:c:", opt, 0, 0, 0);
07212ba4	375	if (i < 0)
	376	break;
	377	switch (i) {
	378	case 'h':
	379	help(stdout);
	380	exit(0);
	381	case 'v':
	382	version(stdout);
	383	exit(0);
	384	case 'u':
	385	usage(stdout);
	386	exit(0);
	387	case 'l':
	388	parseaddr(optarg, 0, &pt);
	389	cw.me.sin_port = pt;
	390	break;
	391	case 'p':
	392	parseaddr(optarg, &cw.peer, 0);
	393	break;
ef4a1ab7	394	case 'b':
	395	parseaddr(optarg, &bindaddr.sin_addr, 0);
	396	break;
07212ba4	397	case 'c':
	398	parseaddr(optarg, &connaddr.sin_addr, &pt);
	399	connaddr.sin_port = pt;
	400	break;
	401	default:
	402	f \|= f_bogus;
	403	break;
	404	}
	405	}
	406	if (optind + 2 != argc \|\| (f & f_bogus)) {
	407	usage(stderr);
	408	exit(1);
	409	}
	410
	411	udp_me.sin_family = udp_peer.sin_family = AF_INET;
	412	parseaddr(argv[optind], &udp_me.sin_addr, &pt);
e04c2d50	413	udp_me.sin_port = pt;
07212ba4	414	parseaddr(argv[optind + 1], &udp_peer.sin_addr, &pt);
	415	udp_peer.sin_port = pt;
	416
	417	if ((fd_udp = socket(PF_INET, SOCK_DGRAM, 0)) < 0 \|\|
	418	bind(fd_udp, (struct sockaddr *)&udp_me, sizeof(udp_me)) \|\|
	419	connect(fd_udp, (struct sockaddr *)&udp_peer, sizeof(udp_peer)) \|\|
	420	setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) \|\|
	421	setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) \|\|
	422	nonblockify(fd_udp) \|\| cloexec(fd_udp))
	423	die(1, "couldn't set up UDP socket: %s", strerror(errno));
	424
	425	if (cw.me.sin_port != 0)
	426	dolisten();
	427	else if (connaddr.sin_addr.s_addr != INADDR_ANY) {
	428	int fd;
	429	if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 \|\|
ef4a1ab7	430	bind(fd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) \|\|
07212ba4	431	connect(fd, (struct sockaddr *)&connaddr, sizeof(connaddr)) \|\|
	432	nonblockify(fd) \|\| cloexec(fd))
	433	die(1, "couldn't connect to TCP server: %s", strerror(errno));
	434	dofwd(fd, fd);
	435	} else
	436	dofwd(STDIN_FILENO, STDOUT_FILENO);
	437
	438	for (;;)
	439	sel_select(&sel);
	440	return (0);
	441	}
	442
	443	/----- That's all, folks -------------------------------------------------/