sys-linux.c

unix and linux net driver

 */

void ccp_flags_set (int unit, int isopen, int isup)
{
    if (still_ppp()) {
	int x = get_flags(ppp_dev_fd);
	x = isopen? x | SC_CCP_OPEN : x &~ SC_CCP_OPEN;
	x = isup?   x | SC_CCP_UP   : x &~ SC_CCP_UP;
	set_flags (ppp_dev_fd, x);
    }
}

/********************************************************************
 *
 * get_idle_time - return how long the link has been idle.
 */
int
get_idle_time(u, ip)
    int u;
    struct ppp_idle *ip;
{
    return ioctl(ppp_dev_fd, PPPIOCGIDLE, ip) >= 0;
} 

/********************************************************************
 *
 * get_ppp_stats - return statistics for the link.
 */
int
get_ppp_stats(u, stats)
    int u;
    struct pppd_stats *stats;
{
    struct ifpppstatsreq req;

    memset (&req, 0, sizeof (req));

    req.stats_ptr = (caddr_t) &req.stats;
    strlcpy(req.ifr__name, ifname, sizeof(req.ifr__name));
    if (ioctl(sock_fd, SIOCGPPPSTATS, &req) < 0) {
	error("Couldn't get PPP statistics: %m");
	return 0;
    }
    stats->bytes_in = req.stats.p.ppp_ibytes;
    stats->bytes_out = req.stats.p.ppp_obytes;
    return 1;
}

/********************************************************************
 *
 * ccp_fatal_error - returns 1 if decompression was disabled as a
 * result of an error detected after decompression of a packet,
 * 0 otherwise.  This is necessary because of patent nonsense.
 */

int ccp_fatal_error (int unit)
{
    int x = get_flags(ppp_dev_fd);

    return x & SC_DC_FERROR;
}

/********************************************************************
 *
 * path_to_procfs - find the path to the proc file system mount point
 */
static char proc_path[MAXPATHLEN];
static int proc_path_len;

static char *path_to_procfs(const char *tail)
{
    struct mntent *mntent;
    FILE *fp;

    if (proc_path_len == 0) {
	/* Default the mount location of /proc */
	strlcpy (proc_path, "/proc", sizeof(proc_path));
	proc_path_len = 5;
	fp = fopen(MOUNTED, "r");
	if (fp != NULL) {
	    while ((mntent = getmntent(fp)) != NULL) {
		if (strcmp(mntent->mnt_type, MNTTYPE_IGNORE) == 0)
		    continue;
		if (strcmp(mntent->mnt_type, "proc") == 0) {
		    strlcpy(proc_path, mntent->mnt_dir, sizeof(proc_path));
		    proc_path_len = strlen(proc_path);
		    break;
		}
	    }
	    fclose (fp);
	}
    }

    strlcpy(proc_path + proc_path_len, tail,
	    sizeof(proc_path) - proc_path_len);
    return proc_path;
}

/*
 * /proc/net/route parsing stuff.
 */
#define ROUTE_MAX_COLS	12
FILE *route_fd = (FILE *) 0;
static char route_buffer[512];
static int route_dev_col, route_dest_col, route_gw_col;
static int route_flags_col, route_mask_col;
static int route_num_cols;

static int open_route_table (void);
static void close_route_table (void);
static int read_route_table (struct rtentry *rt);

/********************************************************************
 *
 * close_route_table - close the interface to the route table
 */

static void close_route_table (void)
{
    if (route_fd != (FILE *) 0) {
        fclose (route_fd);
        route_fd = (FILE *) 0;
    }
}

/********************************************************************
 *
 * open_route_table - open the interface to the route table
 */
static char route_delims[] = " \t\n";

static int open_route_table (void)
{
    char *path;

    close_route_table();

    path = path_to_procfs("/net/route");
    route_fd = fopen (path, "r");
    if (route_fd == NULL) {
        error("can't open routing table %s: %m", path);
        return 0;
    }

    route_dev_col = 0;		/* default to usual columns */
    route_dest_col = 1;
    route_gw_col = 2;
    route_flags_col = 3;
    route_mask_col = 7;
    route_num_cols = 8;

    /* parse header line */
    if (fgets(route_buffer, sizeof(route_buffer), route_fd) != 0) {
	char *p = route_buffer, *q;
	int col;
	for (col = 0; col < ROUTE_MAX_COLS; ++col) {
	    int used = 1;
	    if ((q = strtok(p, route_delims)) == 0)
		break;
	    if (strcasecmp(q, "iface") == 0)
		route_dev_col = col;
	    else if (strcasecmp(q, "destination") == 0)
		route_dest_col = col;
	    else if (strcasecmp(q, "gateway") == 0)
		route_gw_col = col;
	    else if (strcasecmp(q, "flags") == 0)
		route_flags_col = col;
	    else if (strcasecmp(q, "mask") == 0)
		route_mask_col = col;
	    else
		used = 0;
	    if (used && col >= route_num_cols)
		route_num_cols = col + 1;
	    p = NULL;
	}
    }

    return 1;
}

/********************************************************************
 *
 * read_route_table - read the next entry from the route table
 */

static int read_route_table(struct rtentry *rt)
{
    char *cols[ROUTE_MAX_COLS], *p;
    int col;
	
    memset (rt, '\0', sizeof (struct rtentry));

    if (fgets (route_buffer, sizeof (route_buffer), route_fd) == (char *) 0)
	return 0;

    p = route_buffer;
    for (col = 0; col < route_num_cols; ++col) {
	cols[col] = strtok(p, route_delims);
	if (cols[col] == NULL)
	    return 0;		/* didn't get enough columns */
	p = NULL;
    }

    SIN_ADDR(rt->rt_dst) = strtoul(cols[route_dest_col], NULL, 16);
    SIN_ADDR(rt->rt_gateway) = strtoul(cols[route_gw_col], NULL, 16);
    SIN_ADDR(rt->rt_genmask) = strtoul(cols[route_mask_col], NULL, 16);

    rt->rt_flags = (short) strtoul(cols[route_flags_col], NULL, 16);
    rt->rt_dev   = cols[route_dev_col];

    return 1;
}

/********************************************************************
 *
 * defaultroute_exists - determine if there is a default route
 */

static int defaultroute_exists (struct rtentry *rt)
{
    int result = 0;

    if (!open_route_table())
        return 0;

    while (read_route_table(rt) != 0) {
        if ((rt->rt_flags & RTF_UP) == 0)
	    continue;

	if (kernel_version > KVERSION(2,1,0) && SIN_ADDR(rt->rt_genmask) != 0)
	    continue;
        if (SIN_ADDR(rt->rt_dst) == 0L) {
	    result = 1;
	    break;
	}
    }

    close_route_table();
    return result;
}

/*
 * have_route_to - determine if the system has any route to
 * a given IP address.  `addr' is in network byte order.
 * Return value is 1 if yes, 0 if no, -1 if don't know.
 * For demand mode to work properly, we have to ignore routes
 * through our own interface.
 */
int have_route_to(u_int32_t addr)
{
    struct rtentry rt;
    int result = 0;

    if (!open_route_table())
	return -1;		/* don't know */

    while (read_route_table(&rt)) {
	if ((rt.rt_flags & RTF_UP) == 0 || strcmp(rt.rt_dev, ifname) == 0)
	    continue;
	if ((addr & SIN_ADDR(rt.rt_genmask)) == SIN_ADDR(rt.rt_dst)) {
	    result = 1;
	    break;
	}
    }

    close_route_table();
    return result;
}

/********************************************************************
 *
 * sifdefaultroute - assign a default route through the address given.
 */

int sifdefaultroute (int unit, u_int32_t ouraddr, u_int32_t gateway)
{
    struct rtentry rt;

    if (defaultroute_exists(&rt) && strcmp(rt.rt_dev, ifname) != 0) {
	u_int32_t old_gateway = SIN_ADDR(rt.rt_gateway);

	if (old_gateway != gateway)
	    error("not replacing existing default route to %s [%I]",
		  rt.rt_dev, old_gateway);
	return 0;
    }

    memset (&rt, '\0', sizeof (rt));
    SET_SA_FAMILY (rt.rt_dst,     AF_INET);
    SET_SA_FAMILY (rt.rt_gateway, AF_INET);

    if (kernel_version > KVERSION(2,1,0)) {
	SET_SA_FAMILY (rt.rt_genmask, AF_INET);
	SIN_ADDR(rt.rt_genmask) = 0L;
    }

    SIN_ADDR(rt.rt_gateway) = gateway;
    
    rt.rt_flags = RTF_UP | RTF_GATEWAY;
    if (ioctl(sock_fd, SIOCADDRT, &rt) < 0) {
	if ( ! ok_error ( errno ))
	    error("default route ioctl(SIOCADDRT): %m(%d)", errno);
	return 0;
    }

    default_route_gateway = gateway;
    return 1;
}

/********************************************************************
 *
 * cifdefaultroute - delete a default route through the address given.
 */

int cifdefaultroute (int unit, u_int32_t ouraddr, u_int32_t gateway)
{
    struct rtentry rt;

    default_route_gateway = 0;

    memset (&rt, '\0', sizeof (rt));
    SET_SA_FAMILY (rt.rt_dst,     AF_INET);
    SET_SA_FAMILY (rt.rt_gateway, AF_INET);

    if (kernel_version > KVERSION(2,1,0)) {
	SET_SA_FAMILY (rt.rt_genmask, AF_INET);
	SIN_ADDR(rt.rt_genmask) = 0L;
    }

    SIN_ADDR(rt.rt_gateway) = gateway;
    
    rt.rt_flags = RTF_UP | RTF_GATEWAY;
    if (ioctl(sock_fd, SIOCDELRT, &rt) < 0 && errno != ESRCH) {
	if (still_ppp()) {
	    if ( ! ok_error ( errno ))
		error("default route ioctl(SIOCDELRT): %m (%d)", errno);
	    return 0;
	}
    }

    return 1;
}

/********************************************************************
 *
 * sifproxyarp - Make a proxy ARP entry for the peer.
 */

int sifproxyarp (int unit, u_int32_t his_adr)
{
    struct arpreq arpreq;
    char *forw_path;

    if (has_proxy_arp == 0) {
	memset (&arpreq, '\0', sizeof(arpreq));
    
	SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
	SIN_ADDR(arpreq.arp_pa) = his_adr;
	arpreq.arp_flags = ATF_PERM | ATF_PUBL;
/*
 * Get the hardware address of an interface on the same subnet
 * as our local address.
 */
	if (!get_ether_addr(his_adr, &arpreq.arp_ha, proxy_arp_dev,
			    sizeof(proxy_arp_dev))) {
	    error("Cannot determine ethernet address for proxy ARP");
	    return 0;
	}
	strlcpy(arpreq.arp_dev, proxy_arp_dev, sizeof(arpreq.arp_dev));

	if (ioctl(sock_fd, SIOCSARP, (caddr_t)&arpreq) < 0) {
	    if ( ! ok_error ( errno ))
		error("ioctl(SIOCSARP): %m(%d)", errno);
	    return 0;
	}
	proxy_arp_addr = his_adr;
	has_proxy_arp = 1;

	if (tune_kernel) {
	    forw_path = path_to_procfs("/sys/net/ipv4/ip_forward");
	    if (forw_path != 0) {
		int fd = open(forw_path, O_WRONLY);
		if (fd >= 0) {
		    if (write(fd, "1", 1) != 1)
			error("Couldn't enable IP forwarding: %m");
		    close(fd);
		}
	    }
	}
    }

    return 1;
}

/********************************************************************
 *
 * cifproxyarp - Delete the proxy ARP entry for the peer.
 */

int cifproxyarp (int unit, u_int32_t his_adr)
{
    struct arpreq arpreq;

    if (has_proxy_arp) {
	has_proxy_arp = 0;
	memset (&arpreq, '\0', sizeof(arpreq));
	SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
	SIN_ADDR(arpreq.arp_pa) = his_adr;
	arpreq.arp_flags = ATF_PERM | ATF_PUBL;
	strlcpy(arpreq.arp_dev, proxy_arp_dev, sizeof(arpreq.arp_dev));

	if (ioctl(sock_fd, SIOCDARP, (caddr_t)&arpreq) < 0) {
	    if ( ! ok_error ( errno ))
		warn("ioctl(SIOCDARP): %m(%d)", errno);
	    return 0;
	}
    }
    return 1;
}
     
/********************************************************************
 *
 * get_ether_addr - get the hardware address of an interface on the
 * the same subnet as ipaddr.
 */

static int get_ether_addr (u_int32_t ipaddr,
			   struct sockaddr *hwaddr,
			   char *name, int namelen)
{
    struct ifreq *ifr, *ifend;
    u_int32_t ina, mask;
    char *aliasp;
    struct ifreq ifreq;
    struct ifconf ifc;
    struct ifreq ifs[MAX_IFS];
    
    ifc.ifc_len = sizeof(ifs);
    ifc.ifc_req = ifs;
    if (ioctl(sock_fd, SIOCGIFCONF, &ifc) < 0) {
	if ( ! ok_error ( errno ))
	    error("ioctl(SIOCGIFCONF): %m(%d)", errno);
	return 0;
    }

    SYSDEBUG ((LOG_DEBUG, "proxy arp: scanning %d interfaces for IP %s",
		ifc.ifc_len / sizeof(struct ifreq), ip_ntoa(ipaddr)));
/*
 * Scan through looking for an interface with an Internet
 * address on the same subnet as `ipaddr'.
 */
    ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
    for (ifr = ifc.ifc_req; ifr < ifend; ifr++) {
	if (ifr->ifr_addr.sa_family == AF_INET) {
	    ina = SIN_ADDR(ifr->ifr_addr);
	    strlcpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name));
            SYSDEBUG ((LOG_DEBUG, "proxy arp: examining interface %s",
			ifreq.ifr_name));
/*
 * Check that the interface is up, and not point-to-point
 * nor loopback.
 */
	    if (ioctl(sock_fd, SIOCGIFFLAGS, &ifreq) < 0)
		continue;

	    if (((ifreq.ifr_flags ^ FLAGS_GOOD) & FLAGS_MASK) != 0)
		continue;
/*
 * Get its netmask and check that it's on the right subnet.
 */
	    if (ioctl(sock_fd, SIOCGIFNETMASK, &ifreq) < 0)
	        continue;

	    mask = SIN_ADDR(ifreq.ifr_addr);
	    SYSDEBUG ((LOG_DEBUG, "proxy arp: interface addr %s mask %lx",
			ip_ntoa(ina), ntohl(mask)));

	    if (((ipaddr ^ ina) & mask) != 0)
	        continue;
	    break;
	}
    }
    
    if (ifr >= ifend)
        return 0;

    strlcpy(name, ifreq.ifr_name, namelen);

    /* trim off the :1 in eth0:1 */
    aliasp = strchr(name, ':');
    if (aliasp != 0)
	*aliasp = 0;

    info("found interface %s for proxy arp", name);
/*
 * Now get the hardware address.
 */
    memset (&ifreq.ifr_hwaddr, 0, sizeof (struct sockaddr));
    if (ioctl (sock_fd, SIOCGIFHWADDR, &ifreq) < 0) {
        error("SIOCGIFHWADDR(%s): %m(%d)", ifreq.ifr_name, errno);
        return 0;
    }

    memcpy (hwaddr,