484 lines
12 KiB
C
484 lines
12 KiB
C
/* tcp.c
|
||
Code to handle TCP connections.
|
||
|
||
Copyright (C) 1991, 1992, 1993, 1995 Ian Lance Taylor
|
||
|
||
This file is part of the Taylor UUCP package.
|
||
|
||
This program 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.
|
||
|
||
This program 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 this program; if not, write to the Free Software
|
||
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
||
|
||
The author of the program may be contacted at ian@airs.com or
|
||
c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144.
|
||
*/
|
||
|
||
#include "uucp.h"
|
||
|
||
#if USE_RCS_ID
|
||
const char tcp_rcsid[] = "$FreeBSD$";
|
||
#endif
|
||
|
||
#if HAVE_TCP
|
||
|
||
#include "uudefs.h"
|
||
#include "uuconf.h"
|
||
#include "sysdep.h"
|
||
#include "conn.h"
|
||
#include "system.h"
|
||
|
||
#include <errno.h>
|
||
|
||
#if HAVE_SYS_TYPES_TCP_H
|
||
#include <sys/types.tcp.h>
|
||
#endif
|
||
#include <sys/socket.h>
|
||
#include <netdb.h>
|
||
#include <netinet/in.h>
|
||
#include <arpa/inet.h>
|
||
|
||
#if HAVE_FCNTL_H
|
||
#include <fcntl.h>
|
||
#else
|
||
#if HAVE_SYS_FILE_H
|
||
#include <sys/file.h>
|
||
#endif
|
||
#endif
|
||
|
||
#ifndef FD_CLOEXEC
|
||
#define FD_CLOEXEC 1
|
||
#endif
|
||
|
||
/* This code handles TCP connections. It assumes a Berkeley socket
|
||
interface. */
|
||
|
||
/* The normal "uucp" port number. */
|
||
#define IUUCP_PORT "540"
|
||
|
||
/* Local functions. */
|
||
static void utcp_free P((struct sconnection *qconn));
|
||
static boolean ftcp_open P((struct sconnection *qconn, long ibaud,
|
||
boolean fwait));
|
||
static boolean ftcp_close P((struct sconnection *qconn,
|
||
pointer puuconf,
|
||
struct uuconf_dialer *qdialer,
|
||
boolean fsuccess));
|
||
static boolean ftcp_dial P((struct sconnection *qconn, pointer puuconf,
|
||
const struct uuconf_system *qsys,
|
||
const char *zphone,
|
||
struct uuconf_dialer *qdialer,
|
||
enum tdialerfound *ptdialer));
|
||
static int itcp_getaddrinfo P((const char *zhost, const char *zport,
|
||
const struct addrinfo *hints,
|
||
struct addrinfo **res));
|
||
|
||
/* The command table for a TCP connection. */
|
||
static const struct sconncmds stcpcmds =
|
||
{
|
||
utcp_free,
|
||
NULL, /* pflock */
|
||
NULL, /* pfunlock */
|
||
ftcp_open,
|
||
ftcp_close,
|
||
ftcp_dial,
|
||
fsysdep_conn_read,
|
||
fsysdep_conn_write,
|
||
fsysdep_conn_io,
|
||
NULL, /* pfbreak */
|
||
NULL, /* pfset */
|
||
NULL, /* pfcarrier */
|
||
fsysdep_conn_chat,
|
||
NULL /* pibaud */
|
||
};
|
||
|
||
/* Initialize a TCP connection. */
|
||
|
||
boolean
|
||
fsysdep_tcp_init (qconn)
|
||
struct sconnection *qconn;
|
||
{
|
||
struct ssysdep_conn *q;
|
||
|
||
q = (struct ssysdep_conn *) xmalloc (sizeof (struct ssysdep_conn));
|
||
q->o = -1;
|
||
q->ord = -1;
|
||
q->owr = -1;
|
||
q->zdevice = NULL;
|
||
q->iflags = -1;
|
||
q->iwr_flags = -1;
|
||
q->fterminal = FALSE;
|
||
q->ftli = FALSE;
|
||
q->ibaud = 0;
|
||
|
||
qconn->psysdep = (pointer) q;
|
||
qconn->qcmds = &stcpcmds;
|
||
return TRUE;
|
||
}
|
||
|
||
/* Free a TCP connection. */
|
||
|
||
static void
|
||
utcp_free (qconn)
|
||
struct sconnection *qconn;
|
||
{
|
||
xfree (qconn->psysdep);
|
||
}
|
||
|
||
static boolean
|
||
utcp_init (qsysdep)
|
||
struct ssysdep_conn *qsysdep;
|
||
{
|
||
if (!qsysdep)
|
||
return FALSE;
|
||
if (fcntl (qsysdep->o, F_SETFD,
|
||
fcntl (qsysdep->o, F_GETFD, 0) | FD_CLOEXEC) < 0)
|
||
{
|
||
ulog (LOG_ERROR, "fcntl (FD_CLOEXEC): %s", strerror (errno));
|
||
(void) close (qsysdep->o);
|
||
qsysdep->o = -1;
|
||
return FALSE;
|
||
}
|
||
|
||
qsysdep->iflags = fcntl (qsysdep->o, F_GETFL, 0);
|
||
if (qsysdep->iflags < 0)
|
||
{
|
||
ulog (LOG_ERROR, "fcntl: %s", strerror (errno));
|
||
(void) close (qsysdep->o);
|
||
qsysdep->o = -1;
|
||
return FALSE;
|
||
}
|
||
}
|
||
|
||
/* Open a TCP connection. If the fwait argument is TRUE, we are
|
||
running as a server. Otherwise we are just trying to reach another
|
||
system. */
|
||
|
||
static boolean
|
||
ftcp_open (qconn, ibaud, fwait)
|
||
struct sconnection *qconn;
|
||
long ibaud;
|
||
boolean fwait;
|
||
{
|
||
struct ssysdep_conn *qsysdep;
|
||
struct addrinfo hints, *res, *res0;
|
||
struct sockaddr_storage s;
|
||
const char *zport;
|
||
int zfamily;
|
||
uid_t ieuid;
|
||
boolean fswap;
|
||
int err;
|
||
|
||
ulog_device ("TCP");
|
||
|
||
qsysdep = (struct ssysdep_conn *) qconn->psysdep;
|
||
|
||
qsysdep->o = -1;
|
||
|
||
/* We save our process ID in the qconn structure. This is checked
|
||
in ftcp_close. */
|
||
qsysdep->ipid = getpid ();
|
||
|
||
/* If we aren't waiting for a connection, we're done. */
|
||
if (! fwait)
|
||
return TRUE;
|
||
|
||
/* Run as a server and wait for a new connection. The code in
|
||
uucico.c has already detached us from our controlling terminal.
|
||
From this point on if the server gets an error we exit; we only
|
||
return if we have received a connection. It would be more robust
|
||
to respawn the server if it fails; someday. */
|
||
zport = qconn->qport->uuconf_u.uuconf_stcp.uuconf_zport;
|
||
zfamily = qconn->qport->uuconf_u.uuconf_stcp.uuconf_zfamily;
|
||
memset (&hints, 0, sizeof(hints));
|
||
hints.ai_family = zfamily;
|
||
hints.ai_socktype = SOCK_STREAM;
|
||
hints.ai_flags = AI_PASSIVE;
|
||
if ((err = itcp_getaddrinfo (NULL, zport, &hints, &res0)) != 0)
|
||
{
|
||
ulog (LOG_ERROR, "getaddrinfo (NULL, %s): %s",
|
||
zport, gai_strerror (err));
|
||
return FALSE;
|
||
}
|
||
#if HAVE_GETADDRINFO
|
||
if (zfamily == PF_UNSPEC)
|
||
{
|
||
for (res = res0; res; res = res->ai_next)
|
||
{
|
||
if (res->ai_family == AF_INET6)
|
||
{
|
||
qsysdep->o = socket (res->ai_family, res->ai_socktype,
|
||
res->ai_protocol);
|
||
if (qsysdep->o >= 0)
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
#endif
|
||
if (qsysdep->o < 0)
|
||
{
|
||
for (res = res0; res; res = res->ai_next)
|
||
{
|
||
qsysdep->o = socket (res->ai_family, res->ai_socktype,
|
||
res->ai_protocol);
|
||
if (qsysdep->o >= 0)
|
||
break;
|
||
}
|
||
if (qsysdep->o < 0)
|
||
{
|
||
freeaddrinfo (res);
|
||
ulog (LOG_ERROR, "socket: %s", strerror (errno));
|
||
return FALSE;
|
||
}
|
||
}
|
||
#ifdef IPV6_BINDV6ONLY
|
||
if (res->ai_family == AF_INET6)
|
||
{
|
||
int flag = (zfamily == PF_UNSPEC) ? 0 : 1;
|
||
|
||
if (setsockopt (qsysdep->o, IPPROTO_IPV6, IPV6_BINDV6ONLY,
|
||
(char *)&flag, sizeof (flag)) < 0)
|
||
{
|
||
freeaddrinfo (res);
|
||
ulog (LOG_FATAL, "setsockopt: %s", strerror (errno));
|
||
return FALSE;
|
||
}
|
||
}
|
||
#endif
|
||
if (!utcp_init (qsysdep))
|
||
{
|
||
freeaddrinfo (res);
|
||
return FALSE;
|
||
}
|
||
|
||
/* Swap to our real user ID when doing the bind call. This will
|
||
permit the server to use privileged TCP ports when invoked by
|
||
root. We only swap if our effective user ID is not root, so that
|
||
the program can also be made suid root in order to get privileged
|
||
ports when invoked by anybody. */
|
||
fswap = geteuid () != 0;
|
||
if (fswap)
|
||
{
|
||
if (! fsuser_perms (&ieuid))
|
||
{
|
||
(void) close (qsysdep->o);
|
||
qsysdep->o = -1;
|
||
freeaddrinfo (res);
|
||
return FALSE;
|
||
}
|
||
}
|
||
|
||
if (bind (qsysdep->o, res->ai_addr, res->ai_addrlen) < 0)
|
||
{
|
||
freeaddrinfo (res);
|
||
if (fswap)
|
||
(void) fsuucp_perms ((long) ieuid);
|
||
ulog (LOG_FATAL, "bind: %s", strerror (errno));
|
||
}
|
||
freeaddrinfo (res);
|
||
|
||
/* Now swap back to the uucp user ID. */
|
||
if (fswap)
|
||
{
|
||
if (! fsuucp_perms ((long) ieuid))
|
||
ulog (LOG_FATAL, "Could not swap back to UUCP user permissions");
|
||
}
|
||
|
||
if (listen (qsysdep->o, 5) < 0)
|
||
ulog (LOG_FATAL, "listen: %s", strerror (errno));
|
||
|
||
while (! FGOT_SIGNAL ())
|
||
{
|
||
size_t clen;
|
||
int onew;
|
||
pid_t ipid;
|
||
|
||
DEBUG_MESSAGE0 (DEBUG_PORT,
|
||
"ftcp_open: Waiting for connections");
|
||
|
||
clen = sizeof s;
|
||
onew = accept (qsysdep->o, (struct sockaddr *) &s, &clen);
|
||
if (onew < 0)
|
||
ulog (LOG_FATAL, "accept: %s", strerror (errno));
|
||
|
||
DEBUG_MESSAGE0 (DEBUG_PORT,
|
||
"ftcp_open: Got connection; forking");
|
||
|
||
ipid = ixsfork ();
|
||
if (ipid < 0)
|
||
ulog (LOG_FATAL, "fork: %s", strerror (errno));
|
||
if (ipid == 0)
|
||
{
|
||
(void) close (qsysdep->o);
|
||
qsysdep->o = onew;
|
||
|
||
/* Now we fork and let our parent die, so that we become
|
||
a child of init. This lets the main server code wait
|
||
for its child and then continue without accumulating
|
||
zombie children. */
|
||
ipid = ixsfork ();
|
||
if (ipid < 0)
|
||
{
|
||
ulog (LOG_ERROR, "fork: %s", strerror (errno));
|
||
_exit (EXIT_FAILURE);
|
||
}
|
||
|
||
if (ipid != 0)
|
||
_exit (EXIT_SUCCESS);
|
||
|
||
ulog_id (getpid ());
|
||
|
||
return TRUE;
|
||
}
|
||
|
||
(void) close (onew);
|
||
|
||
/* Now wait for the child. */
|
||
(void) ixswait ((unsigned long) ipid, (const char *) NULL);
|
||
}
|
||
|
||
/* We got a signal. */
|
||
usysdep_exit (FALSE);
|
||
|
||
/* Avoid compiler warnings. */
|
||
return FALSE;
|
||
}
|
||
|
||
/* Close the port. */
|
||
|
||
/*ARGSUSED*/
|
||
static boolean
|
||
ftcp_close (qconn, puuconf, qdialer, fsuccess)
|
||
struct sconnection *qconn;
|
||
pointer puuconf;
|
||
struct uuconf_dialer *qdialer;
|
||
boolean fsuccess;
|
||
{
|
||
struct ssysdep_conn *qsysdep;
|
||
boolean fret;
|
||
|
||
qsysdep = (struct ssysdep_conn *) qconn->psysdep;
|
||
fret = TRUE;
|
||
if (qsysdep->o >= 0 && close (qsysdep->o) < 0)
|
||
{
|
||
ulog (LOG_ERROR, "close: %s", strerror (errno));
|
||
fret = FALSE;
|
||
}
|
||
qsysdep->o = -1;
|
||
|
||
/* If the current pid is not the one we used to open the port, then
|
||
we must have forked up above and we are now the child. In this
|
||
case, we are being called from within the fendless loop in
|
||
uucico.c. We return FALSE to force the loop to end and the child
|
||
to exit. This should be handled in a cleaner fashion. */
|
||
if (qsysdep->ipid != getpid ())
|
||
fret = FALSE;
|
||
|
||
return fret;
|
||
}
|
||
|
||
/* Dial out on a TCP port, so to speak: connect to a remote computer. */
|
||
|
||
/*ARGSUSED*/
|
||
static boolean
|
||
ftcp_dial (qconn, puuconf, qsys, zphone, qdialer, ptdialer)
|
||
struct sconnection *qconn;
|
||
pointer puuconf;
|
||
const struct uuconf_system *qsys;
|
||
const char *zphone;
|
||
struct uuconf_dialer *qdialer;
|
||
enum tdialerfound *ptdialer;
|
||
{
|
||
struct ssysdep_conn *qsysdep;
|
||
const char *zhost;
|
||
struct addrinfo hints, *res, *res0;
|
||
int err, connected = FALSE;
|
||
const char *zport;
|
||
char **pzdialer;
|
||
|
||
qsysdep = (struct ssysdep_conn *) qconn->psysdep;
|
||
|
||
*ptdialer = DIALERFOUND_FALSE;
|
||
|
||
zhost = zphone;
|
||
if (zhost == NULL)
|
||
{
|
||
if (qsys == NULL)
|
||
{
|
||
ulog (LOG_ERROR, "No address for TCP connection");
|
||
return FALSE;
|
||
}
|
||
zhost = qsys->uuconf_zname;
|
||
}
|
||
|
||
errno = 0;
|
||
zport = qconn->qport->uuconf_u.uuconf_stcp.uuconf_zport;
|
||
memset (&hints, 0, sizeof(hints));
|
||
hints.ai_family = qconn->qport->uuconf_u.uuconf_stcp.uuconf_zfamily;
|
||
hints.ai_socktype = SOCK_STREAM;
|
||
hints.ai_protocol = 0;
|
||
if ((err = itcp_getaddrinfo (zhost, zport, &hints, &res0)) != 0)
|
||
{
|
||
ulog (LOG_ERROR, "getaddrinfo (%s, %s): %s",
|
||
zhost, zport, gai_strerror (err));
|
||
return FALSE;
|
||
}
|
||
|
||
for (res = res0; res; res = res->ai_next)
|
||
{
|
||
qsysdep->o = socket (res->ai_family, res->ai_socktype, res->ai_protocol);
|
||
if (qsysdep->o < 0)
|
||
continue;
|
||
if (connect (qsysdep->o, res->ai_addr, res->ai_addrlen) >= 0)
|
||
{
|
||
connected = TRUE;
|
||
break;
|
||
}
|
||
close (qsysdep->o);
|
||
}
|
||
freeaddrinfo (res0);
|
||
if (!connected)
|
||
{
|
||
ulog (LOG_ERROR, "connect: %s", strerror (errno));
|
||
return FALSE;
|
||
}
|
||
if (!utcp_init (qsysdep))
|
||
return FALSE;
|
||
|
||
/* Handle the dialer sequence, if any. */
|
||
pzdialer = qconn->qport->uuconf_u.uuconf_stcp.uuconf_pzdialer;
|
||
if (pzdialer != NULL && *pzdialer != NULL)
|
||
{
|
||
if (! fconn_dial_sequence (qconn, puuconf, pzdialer, qsys, zphone,
|
||
qdialer, ptdialer))
|
||
return FALSE;
|
||
}
|
||
|
||
return TRUE;
|
||
}
|
||
|
||
static int
|
||
itcp_getaddrinfo (zhost, zport, hints, res)
|
||
const char *zhost, *zport;
|
||
const struct addrinfo *hints;
|
||
struct addrinfo **res;
|
||
{
|
||
int err;
|
||
|
||
if ((err = getaddrinfo (zhost, zport, hints, res)) != EAI_SERVICE ||
|
||
strcmp(zport, "uucp") != 0)
|
||
return err;
|
||
return getaddrinfo (zhost, IUUCP_PORT, hints, res);
|
||
}
|
||
|
||
#endif /* HAVE_TCP */
|