[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 3 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, see <https://www.gnu.org/licenses/>.
 */

/*----- 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/darray.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>

#include "util.h"

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

typedef union addr {
  struct sockaddr sa;
  struct sockaddr_in sin;
  struct sockaddr_in6 sin6;
} addr;

DA_DECL(addr_v, addr);
DA_DECL(str_v, const char *);

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 {
  unsigned f;				/* Various flags */
#define cwf_port 1u			/*   Port is defined => listen */
  sel_file *sfv;			/* Selectors */
  addr_v me, peer;		       /* Who I'm meant to be; who 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 socklen_t addrsz(const addr *a)
{
  switch (a->sa.sa_family) {
    case AF_INET: return sizeof(a->sin);
    case AF_INET6: return sizeof(a->sin6);
    default: abort();
  }
}

static int knownafp(int af)
{
  switch (af) {
    case AF_INET: case AF_INET6: return (1);
    default: return (0);
  }
}

static int initsock(int fd, int af)
{
  int yes = 1;

  switch (af) {
    case AF_INET: break;
    case AF_INET6:
      if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes)))
	return (-1);
      break;
    default: abort();
  }
  return (0);
}

static const char *addrstr(const addr *a)
{
  static char buf[128];
  socklen_t n = sizeof(buf);

  if (getnameinfo(&a->sa, addrsz(a), buf, n, 0, 0, NI_NUMERICHOST))
    return ("<addrstr failed>");
  return (buf);
}

static int addreq(const addr *a, const addr *b)
{
  if (a->sa.sa_family != b->sa.sa_family) return (0);
  switch (a->sa.sa_family) {
    case AF_INET:
      return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr);
    case AF_INET6:
      return (!memcmp(a->sin6.sin6_addr.s6_addr,
		      b->sin6.sin6_addr.s6_addr,
		      16) &&
	      a->sin6.sin6_scope_id == b->sin6.sin6_scope_id);
    default:
      abort();
  }
}

static void initaddr(addr *a, int af)
{
  a->sa.sa_family = af;
  switch (af) {
    case AF_INET:
      a->sin.sin_addr.s_addr = INADDR_ANY;
      a->sin.sin_port = 0;
      break;
    case AF_INET6:
      memset(a->sin6.sin6_addr.s6_addr, 0, 16);
      a->sin6.sin6_port = 0;
      a->sin6.sin6_flowinfo = 0;
      a->sin6.sin6_scope_id = 0;
      break;
    default:
      abort();
  }
}

#define caf_addr 1u
#define caf_port 2u
static void copyaddr(addr *a, const struct sockaddr *sa, unsigned f)
{
  const struct sockaddr_in *sin;
  const struct sockaddr_in6 *sin6;

  a->sa.sa_family = sa->sa_family;
  switch (sa->sa_family) {
    case AF_INET:
      sin = (const struct sockaddr_in *)sa;
      if (f&caf_addr) a->sin.sin_addr = sin->sin_addr;
      if (f&caf_port) a->sin.sin_port = sin->sin_port;
      break;
    case AF_INET6:
      sin6 = (const struct sockaddr_in6 *)sa;
      if (f&caf_addr) {
	a->sin6.sin6_addr = sin6->sin6_addr;
	a->sin6.sin6_scope_id = sin6->sin6_scope_id;
      }
      if (f&caf_port) a->sin6.sin6_port = sin6->sin6_port;
      /* ??? flowinfo? */
      break;
    default:
      abort();
  }
}

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.f&cwf_port) 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) {
    DISCARD(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;
  addr a;
  socklen_t sz = sizeof(a);
  size_t i, n;

  if ((fd = accept(fd_s, &a.sa, &sz)) < 0) {
    if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) return;
    moan("couldn't accept incoming connection: %s", strerror(errno));
    return;
  }
  n = DA_LEN(&cw.peer);
  if (!n) goto match;
  for (i = 0; i < n; i++) if (addreq(&a, &DA(&cw.peer)[i])) goto match;
  moan("rejecting connection from %s", addrstr(&a));
  close(fd); return;
match:
  if (nonblockify(fd) || cloexec(fd)) {
    moan("couldn't accept incoming connection: %s", strerror(errno));
    close(fd); return;
  }
  dofwd(fd, fd);
  n = DA_LEN(&cw.me);
  for (i = 0; i < n; i++) { close(cw.sfv[i].fd); sel_rmfile(&cw.sfv[i]); }
}

static void dolisten1(const addr *a, sel_file *sf)
{
  int fd;
  int opt = 1;

  if ((fd = socket(a->sa.sa_family, SOCK_STREAM, IPPROTO_TCP)) < 0 ||
      setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) ||
      initsock(fd, a->sa.sa_family) ||
      bind(fd, &a->sa, addrsz(a)) ||
      listen(fd, 1) || nonblockify(fd) || cloexec(fd))
    die(1, "couldn't set up listening socket: %s", strerror(errno));
  sel_initfile(&sel, sf, fd, SEL_READ, doaccept, 0);
  sel_addfile(sf);
}

static void dolisten(void)
{
  size_t i, n;

  n = DA_LEN(&cw.me);
  for (i = 0; i < n; i++)
    dolisten1(&DA(&cw.me)[i], &cw.sfv[i]);
}

static void pushaddrs(addr_v *av, const struct addrinfo *ailist)
{
  const struct addrinfo *ai;
  size_t i, n;

  for (ai = ailist, n = 0; ai; ai = ai->ai_next)
    if (knownafp(ai->ai_family)) n++;
  DA_ENSURE(av, n);
  for (i = DA_LEN(av), ai = ailist; ai; ai = ai->ai_next) {
    if (!knownafp(ai->ai_family)) continue;
    initaddr(&DA(av)[i], ai->ai_family);
    copyaddr(&DA(av)[i++], ai->ai_addr, caf_addr | caf_port);
  }
  DA_EXTEND(av, n);
}

#define paf_parse 1u
static void parseaddr(const struct addrinfo *aihint,
		      const char *host, const char *svc, unsigned f,
		      struct addrinfo **ai_out)
{
  char *alloc = 0, *sep;
  int err;

  if (f&paf_parse) {
    alloc = xstrdup(host);
    if (alloc[0] != '[') {
      if ((sep = strchr(alloc, ':')) == 0)
	die(1, "missing port number in address `%s'", host);
      host = alloc; *sep = 0; svc = sep + 1;
    } else {
      if ((sep = strchr(alloc, ']')) == 0 || sep[1] != ':')
	die(1, "bad syntax in address `%s:'", host);
      host = alloc + 1; *sep = 0; svc = sep + 2;
    }
  }

  err = getaddrinfo(host, svc, aihint, ai_out);
  if (err) {
    if (host && svc) {
      die(1, "failed to resolve hostname `%s', service `%s': %s",
	  host, svc, gai_strerror(err));
    } else if (host)
      die(1, "failed to resolve hostname `%s': %s", host, gai_strerror(err));
    else
      die(1, "failed to resolve service `%s': %s", svc, gai_strerror(err));
  }

  xfree(alloc);
}

static void usage(FILE *fp)
{
  pquis(fp,
	"Usage: $ [-46] [-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\
-4, --ipv4		Restrict to IPv4 only.\n\
-6, --ipv6		Restrict to IPv6 only.\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;
  str_v bindhosts = DA_INIT, peerhosts = DA_INIT;
  const char *bindsvc = 0;
  addr bindaddr;
  const char *connhost = 0;
  struct addrinfo aihint = { 0 }, *ai, *ailist;
  int af = AF_UNSPEC;
  int fd = -1;
  int len = 65536;
  size_t i, n;

#define f_bogus 1u

  cw.f = 0;

  ego(argv[0]);
  sel_init(&sel);
  for (;;) {
    static struct option opt[] = {
      { "help",			0,		0,	'h' },
      { "version",		0,		0,	'v' },
      { "usage",		0,		0,	'u' },
      { "ipv4",			0,		0,	'4' },
      { "ipv6",			0,		0,	'6' },
      { "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, "hvu46l: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 '4': af = AF_INET; break;
      case '6': af = AF_INET6; break;
      case 'l': bindsvc = optarg; break;
      case 'p': DA_PUSH(&peerhosts, optarg); break;
      case 'b': DA_PUSH(&bindhosts, optarg); break;
      case 'c': connhost = optarg; break;
      default: f |= f_bogus; break;
    }
  }
  if (optind + 2 != argc || (f&f_bogus)) { usage(stderr); exit(1); }

  if (DA_LEN(&bindhosts) && !bindsvc && !connhost)
    die(1, "bind addr only makes sense when listening or connecting");
  if (DA_LEN(&peerhosts) && !bindsvc)
    die(1, "peer addr only makes sense when listening");
  if (bindsvc && connhost)
    die(1, "can't listen and connect");

  aihint.ai_family = af;
  DA_CREATE(&cw.me); DA_CREATE(&cw.peer);

  n = DA_LEN(&bindhosts);
  if (n || bindsvc) {
    aihint.ai_socktype = SOCK_STREAM;
    aihint.ai_protocol = IPPROTO_TCP;
    aihint.ai_flags = AI_ADDRCONFIG | AI_PASSIVE;
    if (!n) {
      parseaddr(&aihint, 0, bindsvc, 0, &ailist);
      pushaddrs(&cw.me, ailist);
      freeaddrinfo(ailist);
    } else if (!bindsvc) {
      if (n != 1) die(1, "can only bind to one address as client");
      parseaddr(&aihint, DA(&bindhosts)[0], 0, 0, &ailist);
      for (ai = ailist; ai && !knownafp(ai->ai_family); ai = ai->ai_next);
      if (!ai)
	die(1, "no usable addresses returned for `%s'", DA(&bindhosts)[0]);
      initaddr(&bindaddr, ai->ai_family);
      copyaddr(&bindaddr, ai->ai_addr, caf_addr);
      aihint.ai_family = ai->ai_family;
      freeaddrinfo(ailist);
    } else for (i = 0; i < n; i++) {
      parseaddr(&aihint, DA(&bindhosts)[i], bindsvc, 0, &ailist);
      pushaddrs(&cw.me, ailist);
      freeaddrinfo(ailist);
    }
    if (bindsvc) {
      cw.f |= cwf_port;
      n = DA_LEN(&cw.me);
      cw.sfv = xmalloc(n*sizeof(*cw.sfv));
    }
  }

  n = DA_LEN(&peerhosts);
  if (n) {
    aihint.ai_socktype = SOCK_STREAM;
    aihint.ai_protocol = IPPROTO_TCP;
    aihint.ai_flags = AI_ADDRCONFIG;
    for (i = 0; i < n; i++) {
      parseaddr(&aihint, DA(&peerhosts)[i], 0, 0, &ailist);
      pushaddrs(&cw.peer, ailist);
      freeaddrinfo(ailist);
    }
    if (!DA_LEN(&cw.peer)) die(1, "no usable peer addresses");
  }

  if (connhost) {
    aihint.ai_socktype = SOCK_STREAM;
    aihint.ai_protocol = IPPROTO_TCP;
    aihint.ai_flags = AI_ADDRCONFIG;
    parseaddr(&aihint, connhost, 0, paf_parse, &ailist);

    for (ai = ailist; ai; ai = ai->ai_next) {
      if ((fd = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP)) >= 0 &&
	  !initsock(fd, ai->ai_family) &&
	  (!DA_LEN(&bindhosts) ||
	   !bind(fd, &bindaddr.sa, addrsz(&bindaddr))) &&
	  !connect(fd, ai->ai_addr, ai->ai_addrlen))
	goto conn_tcp;
      if (fd >= 0) close(fd);
    }
    die(1, "couldn't connect to TCP server: %s", strerror(errno));
  conn_tcp:
    if (nonblockify(fd) || cloexec(fd))
      die(1, "couldn't connect to TCP server: %s", strerror(errno));
  }

  aihint.ai_family = af;
  aihint.ai_socktype = SOCK_DGRAM;
  aihint.ai_protocol = IPPROTO_UDP;
  aihint.ai_flags = AI_ADDRCONFIG | AI_PASSIVE;
  parseaddr(&aihint, argv[optind], 0, paf_parse, &ailist);
  for (ai = ailist; ai && !knownafp(ai->ai_family); ai = ai->ai_next);
  if (!ai) die(1, "no usable addresses returned for `%s'", argv[optind]);
  if ((fd_udp = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP)) < 0 ||
      initsock(fd_udp, ai->ai_family) ||
      nonblockify(fd_udp) || cloexec(fd_udp) ||
      setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
      setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) ||
      bind(fd_udp, ai->ai_addr, ai->ai_addrlen))
    die(1, "couldn't set up UDP socket: %s", strerror(errno));
  freeaddrinfo(ailist);
  aihint.ai_family = ai->ai_family;
  aihint.ai_flags = AI_ADDRCONFIG;
  parseaddr(&aihint, argv[optind + 1], 0, paf_parse, &ailist);
  for (ai = ailist; ai; ai = ai->ai_next)
    if (!connect(fd_udp, ai->ai_addr, ai->ai_addrlen)) goto conn_udp;
  die(1, "couldn't set up UDP socket: %s", strerror(errno));
conn_udp:

  if (bindsvc) dolisten();
  else if (connhost) dofwd(fd, fd);
  else dofwd(STDIN_FILENO, STDOUT_FILENO);

  for (;;) {
    if (sel_select(&sel) && errno != EINTR)
      die(1, "select failed: %s", strerror(errno));
  }
  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	*
11ad66c2 MW	12	* TrIPE is free software: you can redistribute it and/or modify it under
	13	* the terms of the GNU General Public License as published by the Free
	14	* Software Foundation; either version 3 of the License, or (at your
	15	* option) any later version.
e04c2d50	16	*
11ad66c2 MW	17	* TrIPE is distributed in the hope that it will be useful, but WITHOUT
	18	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	19	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	20	* for more details.
e04c2d50	21	*
07212ba4	22	* You should have received a copy of the GNU General Public License
11ad66c2	23	* along with TrIPE. If not, see <https://www.gnu.org/licenses/>.
07212ba4	24	*/
07212ba4	25
07212ba4	26	/----- Header files ------------------------------------------------------/
	27
	28	#include "config.h"
	29
	30	#include <ctype.h>
	31	#include <errno.h>
	32	#include <stdio.h>
	33	#include <stdlib.h>
	34	#include <string.h>
	35
	36	#include <sys/time.h>
	37	#include <sys/types.h>
	38	#include <unistd.h>
	39	#include <fcntl.h>
	40	#include <sys/uio.h>
	41	#include <sys/socket.h>
	42	#include <netinet/in.h>
	43	#include <arpa/inet.h>
	44	#include <netdb.h>
	45
	46	#include <mLib/alloc.h>
	47	#include <mLib/bits.h>
5c8525cb	48	#include <mLib/darray.h>
07212ba4	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
23df0e5b MW	57	#include "util.h"
23df0e5b MW	58
07212ba4	59	/----- Data structures ---------------------------------------------------/
07212ba4	60
5db82aca MW	61	typedef union addr {
	62	struct sockaddr sa;
	63	struct sockaddr_in sin;
e7fb7115	64	struct sockaddr_in6 sin6;
5db82aca MW	65	} addr;
5db82aca MW	66
5c8525cb MW	67	DA_DECL(addr_v, addr);
	68	DA_DECL(str_v, const char *);
	69
07212ba4	70	typedef struct pk {
	71	struct pk next; / Next packet in the chain */
	72	octet p, o; /* Buffer start and current posn */
	73	size_t n; /* Size of packet remaining */
	74	} pk;
	75
	76	typedef struct pkstream {
	77	unsigned f; /* Flags... */
	78	#define PKF_FULL 1u /* Buffer is full: stop reading */
	79	sel_file r, w; /* Read and write selectors */
	80	pk pks, pk_tail; / Packet queue */
	81	size_t npk, szpk; /* Number and size of data */
	82	selpk p; /* Packet parser */
	83	} pkstream;
	84
	85	typedef struct connwait {
8fc71d5a MW	86	unsigned f; /* Various flags */
8fc71d5a MW	87	#define cwf_port 1u /* Port is defined => listen */
5c8525cb MW	88	sel_file sfv; / Selectors */
5c8525cb MW	89	addr_v me, peer; /* Who I'm meant to be; who peer is */
07212ba4	90	} connwait;
	91
	92	/----- Static variables --------------------------------------------------/
	93
	94	static sel_state sel;
	95	static connwait cw;
	96	static int fd_udp;
1afc65b6	97	static size_t pk_nmax = 128, pk_szmax = 1024*1024;
07212ba4	98
	99	/----- Main code ---------------------------------------------------------/
	100
	101	static int nonblockify(int fd)
f98df549	102	{ return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)); }
07212ba4	103
07212ba4	104	static int cloexec(int fd)
f98df549	105	{ return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC)); }
07212ba4	106
5426c57a MW	107	static socklen_t addrsz(const addr *a)
	108	{
	109	switch (a->sa.sa_family) {
	110	case AF_INET: return sizeof(a->sin);
e7fb7115	111	case AF_INET6: return sizeof(a->sin6);
5426c57a MW	112	default: abort();
	113	}
	114	}
	115
d66e33f0 MW	116	static int knownafp(int af)
	117	{
	118	switch (af) {
e7fb7115	119	case AF_INET: case AF_INET6: return (1);
d66e33f0 MW	120	default: return (0);
	121	}
	122	}
	123
2fb1657b MW	124	static int initsock(int fd, int af)
2fb1657b MW	125	{
e7fb7115 MW	126	int yes = 1;
e7fb7115 MW	127
2fb1657b MW	128	switch (af) {
2fb1657b MW	129	case AF_INET: break;
e7fb7115 MW	130	case AF_INET6:
	131	if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes)))
	132	return (-1);
	133	break;
2fb1657b MW	134	default: abort();
	135	}
	136	return (0);
	137	}
	138
5426c57a MW	139	static const char addrstr(const addr a)
	140	{
	141	static char buf[128];
	142	socklen_t n = sizeof(buf);
	143
	144	if (getnameinfo(&a->sa, addrsz(a), buf, n, 0, 0, NI_NUMERICHOST))
	145	return ("<addrstr failed>");
	146	return (buf);
	147	}
	148
	149	static int addreq(const addr a, const addr b)
	150	{
	151	if (a->sa.sa_family != b->sa.sa_family) return (0);
	152	switch (a->sa.sa_family) {
	153	case AF_INET:
	154	return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr);
e7fb7115 MW	155	case AF_INET6:
	156	return (!memcmp(a->sin6.sin6_addr.s6_addr,
	157	b->sin6.sin6_addr.s6_addr,
	158	16) &&
	159	a->sin6.sin6_scope_id == b->sin6.sin6_scope_id);
5426c57a MW	160	default:
	161	abort();
	162	}
	163	}
	164
d66e33f0	165	static void initaddr(addr *a, int af)
3912d793	166	{
d66e33f0 MW	167	a->sa.sa_family = af;
	168	switch (af) {
	169	case AF_INET:
	170	a->sin.sin_addr.s_addr = INADDR_ANY;
	171	a->sin.sin_port = 0;
	172	break;
e7fb7115 MW	173	case AF_INET6:
	174	memset(a->sin6.sin6_addr.s6_addr, 0, 16);
	175	a->sin6.sin6_port = 0;
	176	a->sin6.sin6_flowinfo = 0;
	177	a->sin6.sin6_scope_id = 0;
	178	break;
d66e33f0 MW	179	default:
	180	abort();
	181	}
3912d793 MW	182	}
3912d793 MW	183
0bf142d2 MW	184	#define caf_addr 1u
	185	#define caf_port 2u
	186	static void copyaddr(addr a, const struct sockaddr sa, unsigned f)
	187	{
	188	const struct sockaddr_in *sin;
e7fb7115	189	const struct sockaddr_in6 *sin6;
0bf142d2 MW	190
	191	a->sa.sa_family = sa->sa_family;
	192	switch (sa->sa_family) {
	193	case AF_INET:
	194	sin = (const struct sockaddr_in *)sa;
	195	if (f&caf_addr) a->sin.sin_addr = sin->sin_addr;
	196	if (f&caf_port) a->sin.sin_port = sin->sin_port;
	197	break;
e7fb7115 MW	198	case AF_INET6:
	199	sin6 = (const struct sockaddr_in6 *)sa;
	200	if (f&caf_addr) {
	201	a->sin6.sin6_addr = sin6->sin6_addr;
	202	a->sin6.sin6_scope_id = sin6->sin6_scope_id;
	203	}
	204	if (f&caf_port) a->sin6.sin6_port = sin6->sin6_port;
	205	/* ??? flowinfo? */
	206	break;
0bf142d2 MW	207	default:
	208	abort();
	209	}
	210	}
	211
07212ba4	212	static void dolisten(void);
	213
	214	static void doclose(pkstream *p)
	215	{
	216	pk pk, ppk;
	217	close(p->w.fd);
	218	close(p->p.reader.fd);
	219	selpk_destroy(&p->p);
1afc65b6 MW	220	if (!(p->f&PKF_FULL)) sel_rmfile(&p->r);
1afc65b6 MW	221	if (p->npk) sel_rmfile(&p->w);
07212ba4	222	for (pk = p->pks; pk; pk = ppk) {
	223	ppk = pk->next;
	224	xfree(pk->p);
	225	xfree(pk);
	226	}
	227	xfree(p);
8fc71d5a	228	if (cw.f&cwf_port) dolisten();
1afc65b6	229	else exit(0);
07212ba4	230	}
	231
	232	static void rdtcp(octet b, size_t sz, pkbuf pk, size_t k, void vp)
	233	{
	234	pkstream *p = vp;
	235	size_t pksz;
	236
1afc65b6	237	if (!sz) { doclose(p); return; }
07212ba4	238	pksz = LOAD16(b);
07212ba4	239	if (pksz + 2 == sz) {
99735357	240	DISCARD(write(fd_udp, b + 2, pksz));
07212ba4	241	selpk_want(&p->p, 2);
	242	} else {
	243	selpk_want(&p->p, pksz + 2);
	244	*k = sz;
	245	}
	246	}
	247
	248	static void wrtcp(int fd, unsigned mode, void *vp)
	249	{
	250	#define NPK 16
	251	struct iovec iov[NPK];
	252	pkstream *p = vp;
	253	size_t i;
	254	ssize_t n;
	255	pk pk, ppk;
	256
	257	for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) {
	258	iov[i].iov_base = pk->o;
	259	iov[i].iov_len = pk->n;
	260	}
	261
	262	if ((n = writev(fd, iov, i)) < 0) {
1afc65b6	263	if (errno == EAGAIN \|\| errno == EWOULDBLOCK \|\| errno == EINTR) return;
07212ba4	264	moan("couldn't write to TCP socket: %s", strerror(errno));
	265	doclose(p);
	266	return;
	267	}
	268
	269	p->szpk -= n;
	270	for (pk = p->pks; n && pk; pk = ppk) {
	271	ppk = pk->next;
	272	if (pk->n <= n) {
	273	p->npk--;
	274	n -= pk->n;
	275	xfree(pk->p);
	276	xfree(pk);
	277	} else {
	278	pk->n -= n;
	279	pk->o += n;
	280	break;
	281	}
	282	}
	283	p->pks = pk;
1afc65b6 MW	284	if (!pk) { p->pk_tail = &p->pks; sel_rmfile(&p->w); }
	285	if ((p->f&PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax)
	286	{ p->f &= ~PKF_FULL; sel_addfile(&p->r); }
07212ba4	287	}
	288
	289	static void rdudp(int fd, unsigned mode, void *vp)
	290	{
	291	octet buf[65536];
	292	ssize_t n;
	293	pkstream *p = vp;
	294	pk *pk;
	295
	296	if ((n = read(fd, buf, sizeof(buf))) < 0) {
	297	if (errno == EAGAIN \|\| errno == EWOULDBLOCK \|\| errno == EINTR)
	298	return;
	299	moan("couldn't read from UDP socket: %s", strerror(errno));
	300	return;
	301	}
	302	pk = xmalloc(sizeof(*pk));
	303	pk->next = 0;
	304	pk->p = xmalloc(n + 2);
	305	STORE16(pk->p, n);
	306	memcpy(pk->p + 2, buf, n);
	307	pk->o = pk->p;
	308	pk->n = n + 2;
	309	*p->pk_tail = pk;
	310	p->pk_tail = &pk->next;
1afc65b6	311	if (!p->npk) sel_addfile(&p->w);
07212ba4	312	sel_force(&p->w);
	313	p->npk++;
	314	p->szpk += n + 2;
1afc65b6 MW	315	if (p->npk >= pk_nmax \|\| p->szpk >= pk_szmax)
1afc65b6 MW	316	{ sel_rmfile(&p->r); p->f \|= PKF_FULL; }
07212ba4	317	}
	318
	319	static void dofwd(int fd_in, int fd_out)
	320	{
	321	pkstream p = xmalloc(sizeof(p));
	322	sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p);
	323	sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p);
	324	selpk_init(&p->p, &sel, fd_in, rdtcp, p);
	325	selpk_want(&p->p, 2);
	326	p->pks = 0;
	327	p->pk_tail = &p->pks;
	328	p->npk = p->szpk = 0;
	329	p->f = 0;
	330	sel_addfile(&p->r);
	331	}
	332
	333	static void doaccept(int fd_s, unsigned mode, void *p)
	334	{
	335	int fd;
5db82aca MW	336	addr a;
5db82aca MW	337	socklen_t sz = sizeof(a);
5c8525cb	338	size_t i, n;
07212ba4	339
5db82aca	340	if ((fd = accept(fd_s, &a.sa, &sz)) < 0) {
1afc65b6	341	if (errno == EAGAIN \|\| errno == EWOULDBLOCK \|\| errno == EINTR) return;
07212ba4	342	moan("couldn't accept incoming connection: %s", strerror(errno));
	343	return;
	344	}
5c8525cb MW	345	n = DA_LEN(&cw.peer);
	346	if (!n) goto match;
	347	for (i = 0; i < n; i++) if (addreq(&a, &DA(&cw.peer)[i])) goto match;
	348	moan("rejecting connection from %s", addrstr(&a));
	349	close(fd); return;
	350	match:
07212ba4	351	if (nonblockify(fd) \|\| cloexec(fd)) {
07212ba4	352	moan("couldn't accept incoming connection: %s", strerror(errno));
1afc65b6	353	close(fd); return;
07212ba4	354	}
07212ba4	355	dofwd(fd, fd);
5c8525cb MW	356	n = DA_LEN(&cw.me);
5c8525cb MW	357	for (i = 0; i < n; i++) { close(cw.sfv[i].fd); sel_rmfile(&cw.sfv[i]); }
07212ba4	358	}
07212ba4	359
5c8525cb	360	static void dolisten1(const addr a, sel_file sf)
07212ba4	361	{
	362	int fd;
	363	int opt = 1;
	364
5c8525cb	365	if ((fd = socket(a->sa.sa_family, SOCK_STREAM, IPPROTO_TCP)) < 0 \|\|
07212ba4	366	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) \|\|
2fb1657b	367	initsock(fd, a->sa.sa_family) \|\|
5c8525cb	368	bind(fd, &a->sa, addrsz(a)) \|\|
07212ba4	369	listen(fd, 1) \|\| nonblockify(fd) \|\| cloexec(fd))
07212ba4	370	die(1, "couldn't set up listening socket: %s", strerror(errno));
5c8525cb MW	371	sel_initfile(&sel, sf, fd, SEL_READ, doaccept, 0);
	372	sel_addfile(sf);
	373	}
	374
	375	static void dolisten(void)
	376	{
	377	size_t i, n;
	378
	379	n = DA_LEN(&cw.me);
	380	for (i = 0; i < n; i++)
	381	dolisten1(&DA(&cw.me)[i], &cw.sfv[i]);
	382	}
	383
0bf142d2	384	static void pushaddrs(addr_v av, const struct addrinfo ailist)
5c8525cb	385	{
0bf142d2 MW	386	const struct addrinfo *ai;
	387	size_t i, n;
	388
d66e33f0 MW	389	for (ai = ailist, n = 0; ai; ai = ai->ai_next)
d66e33f0 MW	390	if (knownafp(ai->ai_family)) n++;
0bf142d2 MW	391	DA_ENSURE(av, n);
0bf142d2 MW	392	for (i = DA_LEN(av), ai = ailist; ai; ai = ai->ai_next) {
d66e33f0 MW	393	if (!knownafp(ai->ai_family)) continue;
d66e33f0 MW	394	initaddr(&DA(av)[i], ai->ai_family);
0bf142d2 MW	395	copyaddr(&DA(av)[i++], ai->ai_addr, caf_addr \| caf_port);
	396	}
	397	DA_EXTEND(av, n);
07212ba4	398	}
07212ba4	399
3912d793	400	#define paf_parse 1u
0bf142d2 MW	401	static void parseaddr(const struct addrinfo *aihint,
	402	const char host, const char svc, unsigned f,
	403	struct addrinfo **ai_out)
07212ba4	404	{
3912d793	405	char alloc = 0, sep;
0bf142d2	406	int err;
1afc65b6	407
3912d793 MW	408	if (f&paf_parse) {
3912d793 MW	409	alloc = xstrdup(host);
8cc74f87 MW	410	if (alloc[0] != '[') {
	411	if ((sep = strchr(alloc, ':')) == 0)
	412	die(1, "missing port number in address `%s'", host);
	413	host = alloc; *sep = 0; svc = sep + 1;
	414	} else {
	415	if ((sep = strchr(alloc, ']')) == 0 \|\| sep[1] != ':')
	416	die(1, "bad syntax in address `%s:'", host);
	417	host = alloc + 1; *sep = 0; svc = sep + 2;
	418	}
07212ba4	419	}
07212ba4	420
0bf142d2 MW	421	err = getaddrinfo(host, svc, aihint, ai_out);
	422	if (err) {
	423	if (host && svc) {
	424	die(1, "failed to resolve hostname `%s', service `%s': %s",
	425	host, svc, gai_strerror(err));
	426	} else if (host)
	427	die(1, "failed to resolve hostname `%s': %s", host, gai_strerror(err));
3912d793	428	else
0bf142d2	429	die(1, "failed to resolve service `%s': %s", svc, gai_strerror(err));
07212ba4	430	}
3912d793 MW	431
3912d793 MW	432	xfree(alloc);
07212ba4	433	}
	434
	435	static void usage(FILE *fp)
	436	{
	437	pquis(fp,
e7fb7115	438	"Usage: $ [-46] [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\
ef4a1ab7	439	ADDR:PORT ADDR:PORT\n");
07212ba4	440	}
	441
	442	static void version(FILE *fp)
f98df549	443	{ pquis(fp, "$, tripe version " VERSION "\n"); }
07212ba4	444
	445	static void help(FILE *fp)
	446	{
	447	version(fp);
	448	fputc('\n', fp);
	449	usage(fp);
	450	fputs("\n\
	451	Options:\n\
	452	\n\
	453	-h, --help Display this help text.\n\
	454	-v, --version Display version number.\n\
	455	-u, --usage Display pointless usage message.\n\
	456	\n\
e7fb7115 MW	457	-4, --ipv4 Restrict to IPv4 only.\n\
e7fb7115 MW	458	-6, --ipv6 Restrict to IPv6 only.\n\
07212ba4	459	-l, --listen=PORT Listen for connections to TCP PORT.\n\
ef4a1ab7	460	-p, --peer=ADDR Only accept connections from IP ADDR.\n\
ef4a1ab7	461	-b, --bind=ADDR Bind to ADDR before connecting.\n\
07212ba4	462	-c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
	463	\n\
	464	Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
	465	stdout; though it can use TCP sockets instead.\n\
	466	", fp);
	467	}
	468
	469	int main(int argc, char *argv[])
	470	{
	471	unsigned f = 0;
5c8525cb MW	472	str_v bindhosts = DA_INIT, peerhosts = DA_INIT;
5c8525cb MW	473	const char *bindsvc = 0;
5db82aca	474	addr bindaddr;
3912d793	475	const char *connhost = 0;
0bf142d2	476	struct addrinfo aihint = { 0 }, ai, ailist;
e7fb7115	477	int af = AF_UNSPEC;
3912d793	478	int fd = -1;
07212ba4	479	int len = 65536;
5c8525cb	480	size_t i, n;
07212ba4	481
	482	#define f_bogus 1u
	483
8fc71d5a MW	484	cw.f = 0;
8fc71d5a MW	485
07212ba4	486	ego(argv[0]);
07212ba4	487	sel_init(&sel);
	488	for (;;) {
	489	static struct option opt[] = {
	490	{ "help", 0, 0, 'h' },
	491	{ "version", 0, 0, 'v' },
	492	{ "usage", 0, 0, 'u' },
e7fb7115 MW	493	{ "ipv4", 0, 0, '4' },
e7fb7115 MW	494	{ "ipv6", 0, 0, '6' },
07212ba4	495	{ "listen", OPTF_ARGREQ, 0, 'l' },
07212ba4	496	{ "peer", OPTF_ARGREQ, 0, 'p' },
ef4a1ab7	497	{ "bind", OPTF_ARGREQ, 0, 'b' },
07212ba4	498	{ "connect", OPTF_ARGREQ, 0, 'c' },
	499	{ 0, 0, 0, 0 }
	500	};
	501	int i;
	502
e7fb7115	503	i = mdwopt(argc, argv, "hvu46l:p:b:c:", opt, 0, 0, 0);
07212ba4	504	if (i < 0)
	505	break;
	506	switch (i) {
1afc65b6 MW	507	case 'h': help(stdout); exit(0);
	508	case 'v': version(stdout); exit(0);
	509	case 'u': usage(stdout); exit(0);
e7fb7115 MW	510	case '4': af = AF_INET; break;
e7fb7115 MW	511	case '6': af = AF_INET6; break;
3912d793	512	case 'l': bindsvc = optarg; break;
5c8525cb MW	513	case 'p': DA_PUSH(&peerhosts, optarg); break;
5c8525cb MW	514	case 'b': DA_PUSH(&bindhosts, optarg); break;
3912d793	515	case 'c': connhost = optarg; break;
1afc65b6	516	default: f \|= f_bogus; break;
07212ba4	517	}
07212ba4	518	}
1afc65b6	519	if (optind + 2 != argc \|\| (f&f_bogus)) { usage(stderr); exit(1); }
07212ba4	520
5c8525cb	521	if (DA_LEN(&bindhosts) && !bindsvc && !connhost)
3912d793	522	die(1, "bind addr only makes sense when listening or connecting");
5c8525cb	523	if (DA_LEN(&peerhosts) && !bindsvc)
3912d793 MW	524	die(1, "peer addr only makes sense when listening");
	525	if (bindsvc && connhost)
	526	die(1, "can't listen and connect");
	527
e7fb7115	528	aihint.ai_family = af;
5c8525cb MW	529	DA_CREATE(&cw.me); DA_CREATE(&cw.peer);
	530
	531	n = DA_LEN(&bindhosts);
	532	if (n \|\| bindsvc) {
0bf142d2 MW	533	aihint.ai_socktype = SOCK_STREAM;
	534	aihint.ai_protocol = IPPROTO_TCP;
	535	aihint.ai_flags = AI_ADDRCONFIG \| AI_PASSIVE;
5c8525cb	536	if (!n) {
0bf142d2 MW	537	parseaddr(&aihint, 0, bindsvc, 0, &ailist);
	538	pushaddrs(&cw.me, ailist);
	539	freeaddrinfo(ailist);
5c8525cb MW	540	} else if (!bindsvc) {
5c8525cb MW	541	if (n != 1) die(1, "can only bind to one address as client");
d66e33f0 MW	542	parseaddr(&aihint, DA(&bindhosts)[0], 0, 0, &ailist);
	543	for (ai = ailist; ai && !knownafp(ai->ai_family); ai = ai->ai_next);
	544	if (!ai)
	545	die(1, "no usable addresses returned for `%s'", DA(&bindhosts)[0]);
	546	initaddr(&bindaddr, ai->ai_family);
0bf142d2	547	copyaddr(&bindaddr, ai->ai_addr, caf_addr);
d66e33f0	548	aihint.ai_family = ai->ai_family;
0bf142d2	549	freeaddrinfo(ailist);
5c8525cb	550	} else for (i = 0; i < n; i++) {
0bf142d2 MW	551	parseaddr(&aihint, DA(&bindhosts)[i], bindsvc, 0, &ailist);
	552	pushaddrs(&cw.me, ailist);
	553	freeaddrinfo(ailist);
5c8525cb MW	554	}
5c8525cb MW	555	if (bindsvc) {
8fc71d5a	556	cw.f \|= cwf_port;
5c8525cb MW	557	n = DA_LEN(&cw.me);
5c8525cb MW	558	cw.sfv = xmalloc(nsizeof(cw.sfv));
8fc71d5a	559	}
3912d793 MW	560	}
3912d793 MW	561
5c8525cb MW	562	n = DA_LEN(&peerhosts);
5c8525cb MW	563	if (n) {
0bf142d2 MW	564	aihint.ai_socktype = SOCK_STREAM;
	565	aihint.ai_protocol = IPPROTO_TCP;
	566	aihint.ai_flags = AI_ADDRCONFIG;
5c8525cb	567	for (i = 0; i < n; i++) {
0bf142d2 MW	568	parseaddr(&aihint, DA(&peerhosts)[i], 0, 0, &ailist);
	569	pushaddrs(&cw.peer, ailist);
	570	freeaddrinfo(ailist);
5c8525cb	571	}
d66e33f0	572	if (!DA_LEN(&cw.peer)) die(1, "no usable peer addresses");
5c8525cb	573	}
07212ba4	574
3912d793	575	if (connhost) {
0bf142d2 MW	576	aihint.ai_socktype = SOCK_STREAM;
	577	aihint.ai_protocol = IPPROTO_TCP;
	578	aihint.ai_flags = AI_ADDRCONFIG;
	579	parseaddr(&aihint, connhost, 0, paf_parse, &ailist);
	580
	581	for (ai = ailist; ai; ai = ai->ai_next) {
	582	if ((fd = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP)) >= 0 &&
2fb1657b	583	!initsock(fd, ai->ai_family) &&
0bf142d2 MW	584	(!DA_LEN(&bindhosts) \|\|
	585	!bind(fd, &bindaddr.sa, addrsz(&bindaddr))) &&
	586	!connect(fd, ai->ai_addr, ai->ai_addrlen))
	587	goto conn_tcp;
	588	if (fd >= 0) close(fd);
	589	}
	590	die(1, "couldn't connect to TCP server: %s", strerror(errno));
	591	conn_tcp:
3912d793 MW	592	if (nonblockify(fd) \|\| cloexec(fd))
	593	die(1, "couldn't connect to TCP server: %s", strerror(errno));
	594	}
	595
e7fb7115	596	aihint.ai_family = af;
0bf142d2 MW	597	aihint.ai_socktype = SOCK_DGRAM;
	598	aihint.ai_protocol = IPPROTO_UDP;
	599	aihint.ai_flags = AI_ADDRCONFIG \| AI_PASSIVE;
d66e33f0 MW	600	parseaddr(&aihint, argv[optind], 0, paf_parse, &ailist);
	601	for (ai = ailist; ai && !knownafp(ai->ai_family); ai = ai->ai_next);
	602	if (!ai) die(1, "no usable addresses returned for `%s'", argv[optind]);
0bf142d2	603	if ((fd_udp = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP)) < 0 \|\|
2fb1657b	604	initsock(fd_udp, ai->ai_family) \|\|
3912d793	605	nonblockify(fd_udp) \|\| cloexec(fd_udp) \|\|
07212ba4	606	setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) \|\|
07212ba4	607	setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) \|\|
0bf142d2	608	bind(fd_udp, ai->ai_addr, ai->ai_addrlen))
07212ba4	609	die(1, "couldn't set up UDP socket: %s", strerror(errno));
0bf142d2	610	freeaddrinfo(ailist);
d66e33f0	611	aihint.ai_family = ai->ai_family;
0bf142d2 MW	612	aihint.ai_flags = AI_ADDRCONFIG;
	613	parseaddr(&aihint, argv[optind + 1], 0, paf_parse, &ailist);
	614	for (ai = ailist; ai; ai = ai->ai_next)
	615	if (!connect(fd_udp, ai->ai_addr, ai->ai_addrlen)) goto conn_udp;
	616	die(1, "couldn't set up UDP socket: %s", strerror(errno));
	617	conn_udp:
07212ba4	618
3912d793 MW	619	if (bindsvc) dolisten();
	620	else if (connhost) dofwd(fd, fd);
	621	else dofwd(STDIN_FILENO, STDOUT_FILENO);
07212ba4	622
c14225f6 MW	623	for (;;) {
	624	if (sel_select(&sel) && errno != EINTR)
	625	die(1, "select failed: %s", strerror(errno));
	626	}
07212ba4	627	return (0);
	628	}
	629
	630	/----- That's all, folks -------------------------------------------------/