[tripe] / pkstream.c

/* -*-c-*-
 *
 * $Id: pkstream.c,v 1.2 2003/11/29 23:49:32 mdw Exp $
 *
 * 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.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: pkstream.c,v $
 * Revision 1.2  2003/11/29 23:49:32  mdw
 * Debianization.
 *
 * Revision 1.1  2003/04/23 12:53:28  mdw
 * New pkstream program.
 *
 */

/*----- 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;

  if (!sz) {
    doclose(p);
    return;
  }
  pksz = LOAD16(b);
  if (pksz + 2 == sz) {
    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	*
ef4a1ab7	3	* $Id: pkstream.c,v 1.2 2003/11/29 23:49:32 mdw Exp $
07212ba4	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 $
ef4a1ab7	32	* Revision 1.2 2003/11/29 23:49:32 mdw
	33	* Debianization.
	34	*
07212ba4	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 \|\|
07212ba4	283	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) \|\|
ef4a1ab7	284	bind(fd, (struct sockaddr *)&cw.me, sizeof(cw.me)) \|\|
07212ba4	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,
ef4a1ab7	327	"Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
ef4a1ab7	328	ADDR:PORT ADDR:PORT\n");
07212ba4	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\
ef4a1ab7	349	-p, --peer=ADDR Only accept connections from IP ADDR.\n\
ef4a1ab7	350	-b, --bind=ADDR Bind to ADDR before connecting.\n\
07212ba4	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;
ef4a1ab7	362	struct sockaddr_in connaddr, bindaddr;
07212ba4	363	struct sockaddr_in udp_me, udp_peer;
	364	int len = 65536;
	365
	366	#define f_bogus 1u
	367
	368	ego(argv[0]);
ef4a1ab7	369	bindaddr.sin_family = AF_INET;
	370	bindaddr.sin_addr.s_addr = INADDR_ANY;
	371	bindaddr.sin_port = 0;
07212ba4	372	connaddr.sin_family = AF_INET;
ef4a1ab7	373	connaddr.sin_addr.s_addr = INADDR_ANY;
07212ba4	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' },
ef4a1ab7	386	{ "bind", OPTF_ARGREQ, 0, 'b' },
07212ba4	387	{ "connect", OPTF_ARGREQ, 0, 'c' },
	388	{ 0, 0, 0, 0 }
	389	};
	390	int i;
	391
ef4a1ab7	392	i = mdwopt(argc, argv, "hvul:p:b:c:", opt, 0, 0, 0);
07212ba4	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;
ef4a1ab7	412	case 'b':
	413	parseaddr(optarg, &bindaddr.sin_addr, 0);
	414	break;
07212ba4	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 \|\|
ef4a1ab7	448	bind(fd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) \|\|
07212ba4	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 -------------------------------------------------/