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/* $KAME: tcp.c,v 1.13 2003/09/02 22:49:21 itojun Exp $ */
/*
* Copyright (C) 1997 and 1998 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include "faithd.h"
static char tcpbuf[16*1024];
/* bigger than MSS and may be lesser than window size */
static int tblen, tboff, oob_exists;
static fd_set readfds, writefds, exceptfds;
static char atmark_buf[2];
static pid_t cpid = (pid_t)0;
static pid_t ppid = (pid_t)0;
volatile time_t child_lastactive = (time_t)0;
static time_t parent_lastactive = (time_t)0;
static void sig_ctimeout __P((int));
static void sig_child __P((int));
static void notify_inactive __P((void));
static void notify_active __P((void));
static void send_data __P((int, int, const char *, int));
static void relay __P((int, int, const char *, int));
/*
* Inactivity timer:
* - child side (ppid != 0) will send SIGUSR1 to parent every (FAITH_TIMEOUT/4)
* second if traffic is active. if traffic is inactive, don't send SIGUSR1.
* - parent side (ppid == 0) will check the last SIGUSR1 it have seen.
*/
static void
sig_ctimeout(int sig __unused)
{
/* parent side: record notification from the child */
if (dflag)
syslog(LOG_DEBUG, "activity timer from child");
child_lastactive = time(NULL);
}
/* parent will terminate if child dies. */
static void
sig_child(int sig __unused)
{
int status;
pid_t pid;
pid = wait3(&status, WNOHANG, (struct rusage *)0);
if (pid > 0 && WEXITSTATUS(status))
syslog(LOG_WARNING, "child %ld exit status 0x%x",
(long)pid, status);
exit_success("terminate connection due to child termination");
}
static void
notify_inactive()
{
time_t t;
/* only on parent side... */
if (ppid)
return;
/* parent side should check for timeout. */
t = time(NULL);
if (dflag) {
syslog(LOG_DEBUG, "parent side %sactive, child side %sactive",
(FAITH_TIMEOUT < t - parent_lastactive) ? "in" : "",
(FAITH_TIMEOUT < t - child_lastactive) ? "in" : "");
}
if (FAITH_TIMEOUT < t - child_lastactive
&& FAITH_TIMEOUT < t - parent_lastactive) {
/* both side timeouted */
signal(SIGCHLD, SIG_DFL);
kill(cpid, SIGTERM);
wait(NULL);
exit_failure("connection timeout");
/* NOTREACHED */
}
}
static void
notify_active()
{
if (ppid) {
/* child side: notify parent of active traffic */
time_t t;
t = time(NULL);
if (FAITH_TIMEOUT / 4 < t - child_lastactive) {
if (kill(ppid, SIGUSR1) < 0) {
exit_failure("terminate connection due to parent termination");
/* NOTREACHED */
}
child_lastactive = t;
}
} else {
/* parent side */
parent_lastactive = time(NULL);
}
}
static void
send_data(int s_rcv, int s_snd, const char *service __unused, int direction)
{
int cc;
if (oob_exists) {
cc = send(s_snd, atmark_buf, 1, MSG_OOB);
if (cc == -1)
goto retry_or_err;
oob_exists = 0;
if (s_rcv >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_SET(s_rcv, &exceptfds);
}
for (; tboff < tblen; tboff += cc) {
cc = write(s_snd, tcpbuf + tboff, tblen - tboff);
if (cc < 0)
goto retry_or_err;
}
#ifdef DEBUG
if (tblen) {
if (tblen >= sizeof(tcpbuf))
tblen = sizeof(tcpbuf) - 1;
tcpbuf[tblen] = '\0';
syslog(LOG_DEBUG, "from %s (%dbytes): %s",
direction == 1 ? "client" : "server", tblen, tcpbuf);
}
#endif /* DEBUG */
tblen = 0; tboff = 0;
if (s_snd >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_CLR(s_snd, &writefds);
if (s_rcv >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_SET(s_rcv, &readfds);
return;
retry_or_err:
if (errno != EAGAIN)
exit_failure("writing relay data failed: %s", strerror(errno));
if (s_snd >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_SET(s_snd, &writefds);
}
static void
relay(int s_rcv, int s_snd, const char *service, int direction)
{
int atmark, error, maxfd;
struct timeval tv;
fd_set oreadfds, owritefds, oexceptfds;
FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_ZERO(&exceptfds);
fcntl(s_snd, F_SETFD, O_NONBLOCK);
oreadfds = readfds; owritefds = writefds; oexceptfds = exceptfds;
if (s_rcv >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_SET(s_rcv, &readfds);
FD_SET(s_rcv, &exceptfds);
oob_exists = 0;
maxfd = (s_rcv > s_snd) ? s_rcv : s_snd;
for (;;) {
tv.tv_sec = FAITH_TIMEOUT / 4;
tv.tv_usec = 0;
oreadfds = readfds;
owritefds = writefds;
oexceptfds = exceptfds;
error = select(maxfd + 1, &readfds, &writefds, &exceptfds, &tv);
if (error == -1) {
if (errno == EINTR)
continue;
exit_failure("select: %s", strerror(errno));
} else if (error == 0) {
readfds = oreadfds;
writefds = owritefds;
exceptfds = oexceptfds;
notify_inactive();
continue;
}
/* activity notification */
notify_active();
if (FD_ISSET(s_rcv, &exceptfds)) {
error = ioctl(s_rcv, SIOCATMARK, &atmark);
if (error != -1 && atmark == 1) {
int cc;
oob_read_retry:
cc = read(s_rcv, atmark_buf, 1);
if (cc == 1) {
if (s_rcv >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_CLR(s_rcv, &exceptfds);
if (s_snd >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_SET(s_snd, &writefds);
oob_exists = 1;
} else if (cc == -1) {
if (errno == EINTR)
goto oob_read_retry;
exit_failure("reading oob data failed"
": %s",
strerror(errno));
}
}
}
if (FD_ISSET(s_rcv, &readfds)) {
relaydata_read_retry:
tblen = read(s_rcv, tcpbuf, sizeof(tcpbuf));
tboff = 0;
switch (tblen) {
case -1:
if (errno == EINTR)
goto relaydata_read_retry;
exit_failure("reading relay data failed: %s",
strerror(errno));
/* NOTREACHED */
case 0:
/* to close opposite-direction relay process */
shutdown(s_snd, 0);
close(s_rcv);
close(s_snd);
exit_success("terminating %s relay", service);
/* NOTREACHED */
default:
if (s_rcv >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_CLR(s_rcv, &readfds);
if (s_snd >= FD_SETSIZE)
exit_failure("descriptor too big");
FD_SET(s_snd, &writefds);
break;
}
}
if (FD_ISSET(s_snd, &writefds))
send_data(s_rcv, s_snd, service, direction);
}
}
void
tcp_relay(int s_src, int s_dst, const char *service)
{
syslog(LOG_INFO, "starting %s relay", service);
child_lastactive = parent_lastactive = time(NULL);
cpid = fork();
switch (cpid) {
case -1:
exit_failure("tcp_relay: can't fork grand child: %s",
strerror(errno));
/* NOTREACHED */
case 0:
/* child process: relay going traffic */
ppid = getppid();
/* this is child so reopen log */
closelog();
openlog(logname, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
relay(s_src, s_dst, service, 1);
/* NOTREACHED */
default:
/* parent process: relay coming traffic */
ppid = (pid_t)0;
signal(SIGUSR1, sig_ctimeout);
signal(SIGCHLD, sig_child);
relay(s_dst, s_src, service, 0);
/* NOTREACHED */
}
}
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