/*
 * ppp.c - ppp and pppd control.
 *
 * Copyright (c) 1994, 1995, 1996 Eric Schenk.
 * Copyright (c) 1999 Mike Jagdis.
 * All rights reserved. Please see the file LICENSE which should be
 * distributed with this software for terms of use.
 */

#include "diald.h"

#if 0
#ifdef PPP_VERSION_2_2_0
#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>
#else
#include <linux/ppp.h>
#endif
#else
#define PPPIOCGUNIT_2_1_2 0x5494
#define PPPIOCGUNIT_2_2_0 _IOR('t', 86, int)
#endif

/* internal flag to shortcut repeated calls to setaddr */
static int rx_count = -1;

void ppp_start()
{
    int pgrpid;
#ifdef DEBIAN_REDIRECT_PPPD_STDERR
    int pipes_fd[2];
    int fdflags;
#endif /* ndef DEBIAN_REDIRECT_PPPD_STDERR */

    block_signals();

    link_iface = -1;
    rx_count = -1;

#ifdef DEBIAN_REDIRECT_PPPD_STDERR
    if (pipe(pipes_fd)!=0) {
      unblock_signals();
      syslog(LOG_ERR, "pipe() failed: %m");
      die(1);
    }
    pppd_stderr_fd=pipes_fd[0];
    if ((fdflags=fcntl(pppd_stderr_fd, F_GETFL))==-1) {
      unblock_signals();
      syslog(LOG_ERR, "fcntl(pppd_stderr_fd, F_GETFL) failed: %m");
      die(1);
    }
    fdflags |= O_NONBLOCK;
    if (fcntl(pppd_stderr_fd, F_SETFL, fdflags)==-1) {
      unblock_signals();
      syslog(LOG_ERR, "fcntl(pppd_stderr_fd, F_SETFL) failed: %m");
      die(1);
    }

#endif /* ndef DEBIAN_REDIRECT_PPPD_STDERR */
    /* Run pppd directly here and set up to wait for the iface */
    link_pid = fork();

    if (link_pid < 0) {
        unblock_signals();
	mon_syslog(LOG_ERR, "failed to fork pppd: %m");
	die(1);
    }

#define ADD_ARG(arg) { argv[i] = arg; argv_len += strlen(argv[i++]) + 1; }
    
    if (link_pid == 0) {
	char **argv = (char **)malloc(sizeof(char *)*(pppd_argc+12));
	int argv_len = 0;
	char buf[24], *argv_buf;
	int i = 0, j;;

        default_sigacts();
        unblock_signals();

	ADD_ARG(path_pppd);
	ADD_ARG("-defaultroute");
	ADD_ARG("-detach");
	if (modem) ADD_ARG("modem");
	if (crtscts) ADD_ARG("crtscts");
	ADD_ARG("mtu");
	sprintf(buf,"%d",mtu);
	ADD_ARG(strdup(buf));
	ADD_ARG("mru");
	sprintf(buf,"%d",mru);
	ADD_ARG(strdup(buf));
	if (netmask) {
	  ADD_ARG("netmask");
	  ADD_ARG(netmask);
	}
	for (j = 0; j < pppd_argc; j++) {
	  ADD_ARG(pppd_argv[j]);
	}
	argv[i++] = 0;

	if ((argv_buf = (char *)malloc(argv_len + 1))) {
	  argv_len = i - 1;
	  *argv_buf = '\0';
	  for (i = 0; i < argv_len; i++) {
	    strcat(argv_buf, argv[i]);
	    strcat(argv_buf, " ");
	  }
	  mon_syslog(LOG_DEBUG, "Running pppd: %s", argv_buf);
	}

	/* make sure pppd is the session leader and has the controlling
         * terminal so it gets the SIGHUP's
         */
	pgrpid = setsid();
        ioctl(modem_fd, TIOCSCTTY, 1);
	tcsetpgrp(modem_fd, pgrpid);

	setreuid(getuid(), getuid());
	setregid(getgid(), getgid());

	if (modem_fd != 0)
	    dup2(modem_fd, 0);
	else
	    fcntl(modem_fd, F_SETFD, 0);
	dup2(modem_fd, 1);
#ifdef DEBIAN_REDIRECT_PPPD_STDERR
	dup2(pipes_fd[1], 2);
	close(pipes_fd[0]);
	close(pipes_fd[1]);
#endif /* ndef DEBIAN_REDIRECT_PPPD_STDERR */

	execv(path_pppd,argv);

	mon_syslog(LOG_ERR, "could not exec %s: %m",path_pppd);
	_exit(99);
	/* NOTREACHED */
    }
#ifdef DEBIAN_REDIRECT_PPPD_STDERR
    close(pipes_fd[1]);
#endif /* ndef DEBIAN_REDIRECT_PPPD_STDERR */
    unblock_signals();
    mon_syslog(LOG_INFO,"Running pppd (pid = %d).",link_pid);
}

/*
 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
 * if it exists.
 */

#define SET_SA_FAMILY(addr, family)                     \
    memset ((char *) &(addr), '\0', sizeof(addr));      \
    addr.sa_family = (family);

/*
 * Find the interface number of the ppp device that pppd opened up and
 * do any routing we might need to do.
 * If pppd has not yet opened the device, then return 0, else return 1.
 */

int ppp_set_addrs()
{
    ulong laddr = 0, raddr = 0, baddr = 0;

    /* Try to get the interface number if we don't know it yet. */
    if (link_iface == -1) {
	 /* Try the pppd-2.2.0 ioctrl first,
	  * Try the pppd-2.1.2 ioctrl if that fails
	  */
   	 if (ioctl(modem_fd, PPPIOCGUNIT_2_2_0, &link_iface) == -1)
   	 	ioctl(modem_fd, PPPIOCGUNIT_2_1_2, &link_iface);
    }

    /* Ok then, see if pppd has upped the interface yet. */
    if (link_iface != -1) {
	struct ifreq   ifr; 

	SET_SA_FAMILY (ifr.ifr_addr,    AF_INET); 
	SET_SA_FAMILY (ifr.ifr_dstaddr, AF_INET); 
	SET_SA_FAMILY (ifr.ifr_netmask, AF_INET); 
	sprintf(ifr.ifr_name,"ppp%d",link_iface);
	if (ioctl(sockfd, SIOCGIFFLAGS, (caddr_t) &ifr) == -1) {
	   mon_syslog(LOG_ERR,"failed to read ppp interface status: %m");
	   return 0;
	}
	if (!(ifr.ifr_flags & IFF_UP))
	    return 0;	/* interface is not up yet */

	if (route_wait) {
	    /* set the initial rx counter once the link is up */
	    if (rx_count == -1) rx_count = ppp_rx_count();

	    /* check if we got the routing packet yet */
	    if (ppp_rx_count() == rx_count) return 0;
	}

	/* Ok, the interface is up, grab the addresses. */
	if (ioctl(sockfd, SIOCGIFADDR, (caddr_t) &ifr) == -1)
		mon_syslog(LOG_ERR,"failed to get ppp local address: %m");
	else
       	    laddr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr.s_addr;

	if (ioctl(sockfd, SIOCGIFDSTADDR, (caddr_t) &ifr) == -1) 
	   mon_syslog(LOG_ERR,"failed to get ppp remote address: %m");
	else
	   raddr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr.s_addr;

	if (ioctl(sockfd, SIOCGIFBRDADDR, (caddr_t) &ifr) == -1) 
	   mon_syslog(LOG_ERR,"failed to get ppp broadcast address: %m");
	else
	   baddr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr.s_addr;

 	/* Check the MTU, see if it matches what we asked for. If it
	 * doesn't warn the user and adjust the MTU setting.
	 * (NOTE: Adjusting the MTU setting may cause kernel nastyness...)
	 */
	if (ioctl(sockfd, SIOCGIFMTU, (caddr_t) &ifr) == -1) {
	    mon_syslog(LOG_ERR,"failed to get ppp mtu setting: %m");
	} else {
	    if (ifr.ifr_mtu != mtu) {
	        mon_syslog(LOG_WARNING,"PPP negotiated mtu of %d does not match requested setting %d.",ifr.ifr_mtu,mtu);
		mon_syslog(LOG_WARNING,"Attempting to auto adjust mtu.");
		mon_syslog(LOG_WARNING,"Restart diald with mtu set to %d to avoid errors.",ifr.ifr_mtu);
		mtu = ifr.ifr_mtu;
	    }
	}

	if (dynamic_addrs) {
	    /* only do the configuration in dynamic mode. */
	    struct in_addr addr;
	    addr.s_addr = baddr;
	    if (broadcast_ip) free(broadcast_ip);
	    broadcast_ip = strdup(inet_ntoa(addr));
	    addr.s_addr = raddr;
	    if (remote_ip) free(remote_ip);
	    remote_ip = strdup(inet_ntoa(addr));
	    addr.s_addr = laddr;
	    if (local_ip) free(local_ip);
	    local_ip = strdup(inet_ntoa(addr));
	    local_addr = laddr;
	    if (dynamic_addrs > 1) {
		if (orig_broadcast_ip) free(orig_broadcast_ip);
		orig_broadcast_ip = strdup(broadcast_ip);
		if (orig_remote_ip) free(orig_remote_ip);
		orig_remote_ip = strdup(remote_ip);
		if (orig_local_ip) free(orig_local_ip);
		orig_local_ip = strdup(local_ip);
	    }
	    mon_syslog(LOG_INFO, "New addresses: local %s%s%s%s%s",
		local_ip,
		remote_ip ? ", remote " : "",
		remote_ip ? remote_ip : "",
		broadcast_ip ? ", broadcast " : "",
		broadcast_ip ? broadcast_ip : "");
	}

	/* The pppd should have configured the interface but there
	 * may be user or default routes to add :-(.
	 */
	iface_start("link", "ppp", link_iface,
	    local_ip, remote_ip, broadcast_ip, metric);
	if (proxy.stop)
	    proxy.stop(&proxy);

	return 1;
    }
    return 0;
}

int ppp_dead()
{
    return (link_pid == 0);
}

int ppp_route_exists()
{
    char buf[128];
    int device = 0;
    int found = 0;
    FILE *fp;
    sprintf(buf,"%s -n",path_route);
    if ((fp = popen(buf,"r"))==NULL) {
        mon_syslog(LOG_ERR,"Could not run command '%s': %m",buf);
	return 0;	/* assume half dead in this case... */
    }

    while (fgets(buf,128,fp)) {
	if (sscanf(buf,"%*s %*s %*s %*s %*s %*s %*s ppp%d",&device) == 1) {
	    if (device == link_iface) found = 1;
	}
    }
    fclose(fp);
    return found;
}

int ppp_rx_count()
{
    char buf[128];
    int packets = 0;
    FILE *fp;
    sprintf(buf,"%s ppp%d",path_ifconfig,link_iface);
    if ((fp = popen(buf,"r"))==NULL) {
        mon_syslog(LOG_ERR,"Could not run command '%s': %m",buf);
	return 0;	/* assume half dead in this case... */
    }

    while (fgets(buf,128,fp)) {
	if (sscanf(buf," RX packets:%d",&packets) == 1) {
	    break;
	}
    }
    fclose(fp);
    return packets;
}

void ppp_stop()
{
    if (link_pid)
    	if (kill(link_pid,SIGINT) == -1 && errno == ESRCH)
	    link_pid = 0;
}

void ppp_reroute()
{
    /* Restore the original proxy. */
    if (proxy.start && (!blocked || blocked_route))
	proxy.start(&proxy);
    local_addr = (orig_local_ip ? inet_addr(orig_local_ip) : 0);

    if (link_iface != -1) {
    	iface_stop("link", "ppp", link_iface,
	    local_ip, remote_ip, broadcast_ip, metric);
    	iface_down("link", "ppp", link_iface,
	    local_ip, remote_ip, broadcast_ip, metric);
	link_iface = -1;
    }
}

void ppp_kill()
{
    if (link_pid)
    	if (kill(link_pid,SIGKILL) == -1 && errno == ESRCH)
	    link_pid = 0;
}

void ppp_zombie()
{
    /* Either ppp became a zombie or we missed a SIGCHLD signal */

    sig_chld(SIGKILL);	/* try to reap the child */
    link_pid = 0;	/* just in case the reaping failed, forget zombie */
}