#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <syslog.h>

#include <unistd.h>
#include "netdevice.h"



#define PROC_NET_DEV	"/proc/net/dev"
#define NETDEVICE_MAX	100

static NETDEVICE netdevice[NETDEVICE_MAX];

static void netdevice_add_name( char *name )
{
	NETDEVICE ifn;
	NETDEVICE *ifp;

//fprintf(stderr,"netdevice_add_name: %s\n", name);
	for (ifp=netdevice; (ifn=*ifp); ifp=&ifn->next) {
		if ( strcmp( ifn->name, name ) == 0 ) {
			return;
		}
	}
	if (!(*ifp=(NETDEVICE)malloc(sizeof(**ifp)))) 
		return;
	ifn=*ifp;
	ifn->next=NULL;
	if (strlen(name)>sizeof(ifn->name)-1) 
	name[sizeof(ifn->name)-1]='\0';
	strncpy(ifn->name, name, NETDEVICE_LENGTH);
	ifn->ip = 0;
	ifn->netmask = 0;
	ifn->ip_alfa[0] = '\0';
	ifn->flags = 0;
	ifn->deny_icmp_echo_request = 1;
	ifn->deny_icmp_time_exceeded = 1;
	if ( strncmp( ifn->name, "sl", 2 ) == 0 ) {
		ifn->status_if = STATUS_IF_DOWN;
	} else {
		ifn->status_if = STATUS_IF_INIT;
	}
	ifn->status_fw = STATUS_FW_INIT;
	return;
}


static char *get_netdevice_name(char *name, char *p)
{
    while (isspace(*p))
	p++;
    while (*p) {
	if (isspace(*p))
	    break;
	if (*p == ':') {	/* could be an alias */
	    char *dot = p, *dotname = name;
	    *name++ = *p++;
	    while (isdigit(*p))
		*name++ = *p++;
	    if (*p != ':') {	/* it wasn't, backup */
		p = dot;
		name = dotname;
	    }
	    if (*p == '\0')
		return NULL;
	    p++;
	    break;
	}
	*name++ = *p++;
    }
    *name++ = '\0';
    return p;
}

static char check_RFC1918( struct in_addr net )
{
	if ( 
		(  strcmp( inet_ntoa( net ), "10.0.0.0" ) > 0
		&& strcmp( inet_ntoa( net ), "10.255.255.255" ) < 0 )
		||
		(  strcmp( inet_ntoa( net ), "172.16.0.0" ) > 0
		&& strcmp( inet_ntoa( net ), "172.31.255.255" ) < 0 )
		||
		(  strcmp( inet_ntoa( net ), "192.168.0.0" ) > 0
		&& strcmp( inet_ntoa( net ), "192.168.255.255" ) < 0 )
	) {
//fprintf(stderr,"RFC1918: %s\n", inet_ntoa( net ) );
		return( (char)1 );
	}

//fprintf(stderr,"No RFC1918: %s\n", inet_ntoa( net ) );
	return( (char)0 );

}

/* Fetch the netdevice configuration from the kernel. */
static void if_fetch( NETDEVICE ifn )
{
	static int fd = 0;
	struct ifreq ifr;

	if ( fd == 0 ) {
    		fd = socket(AF_INET, SOCK_DGRAM, 0);
		if ( fd < 0) {
			syslog(LOG_ERR, "Socket error");
			exit(1);
		}
	}
	strcpy(ifr.ifr_name, ifn->name);
	if (ioctl(fd, SIOCGIFFLAGS, &ifr) < 0)
		return;
	ifn->flags = ifr.ifr_flags;
	strcpy(ifr.ifr_name, ifn->name);
	ifr.ifr_addr.sa_family = AF_INET;
	if (ioctl(fd, SIOCGIFADDR, &ifr) == 0) {
		uint32_t ip;
		struct sockaddr_in *sin;
		sin = (struct sockaddr_in *)&ifr.ifr_addr;
		strncpy( ifn->ip_alfa, inet_ntoa( sin->sin_addr ), IP_ALFA );
		ip = ntohl( sin->sin_addr.s_addr );
		if ( ip != ifn->ip ) {
			/*
			 * Change of ip address for netdevice
			 */
			ifn->status_fw = STATUS_FW_DO;
			ifn->ip = ip;
			ifn->RFC1918 = check_RFC1918( sin->sin_addr );
		}

   		strcpy(ifr.ifr_name, ifn->name);
    		if (ioctl(fd, SIOCGIFNETMASK, &ifr) < 0) {
			ifn->netmask = 0;
    		} else {
			sin = (struct sockaddr_in *)&ifr.ifr_netmask;
			ifn->netmask = ntohl( sin->sin_addr.s_addr );
			strncpy( ifn->netmask_alfa, inet_ntoa( sin->sin_addr ), IP_ALFA );
		}
//if ( ifn->status_fw == STATUS_FW_DO )
//fprintf(stderr,"if_fetch: new ip %s %s %s flags=%x\n", ifn->name, ifn->ip_alfa, ifn->netmask_alfa, ifn->flags );
		if ( strncmp( ifn->name, "sl", 2 ) != 0 ) {
			ifn->status_if = STATUS_IF_UP;
		}
		return;
	} else {
		ifn->ip = 0;
		ifn->ip_alfa[0] = '\0';
		if ( ifn->status_fw == STATUS_FW_DONE ) {
			/*
			 * This netdevice does not work any more.
			 * Firewall is to be turned off.
			 */
			ifn->status_fw = STATUS_FW_DO;
		}
		ifn->status_if = STATUS_IF_DOWN;
//fprintf(stderr,"if_fetch: ioctl fail: %s\n", ifn->name );
	}
	return;
}

NETDEVICE *netdevice_read( )
{
	char buf[300];
	NETDEVICE ifn;
	FILE *f;


	f = fopen (PROC_NET_DEV, "r");
	if ( f == NULL ) {
		return( NULL );
	}
	/*
	 * Skip the first line (title line)
	 */
	fgets(buf,sizeof(buf)-1,f);

	while (fgets(buf,sizeof(buf)-1,f)!=NULL){
		char name[20];
		get_netdevice_name( name, buf );
		if ( strcmp( name, "face" ) == 0 ) continue;
		netdevice_add_name( name );
	}
	fclose( f );

	for (ifn=netdevice[0];ifn;ifn=ifn->next) {
		if_fetch( ifn );
		if ( ! (ifn->flags & IFF_UP) ) {
			continue;
		}
	}
	return( netdevice );
}