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Initial revision

/* $Id: upnpredirect.c,v 1.1 2012/02/21 23:16:02 misho Exp $ */
/* MiniUPnP project
 * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
 * (c) 2006-2009 Thomas Bernard 
 * This software is subject to the conditions detailed
 * in the LICENCE file provided within the distribution */

#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>

#include <stdio.h>
#include <ctype.h>
#include <unistd.h>

#include "config.h"
#include "upnpredirect.h"
#include "upnpglobalvars.h"
#include "upnpevents.h"
#if defined(USE_NETFILTER)
#include "netfilter/iptcrdr.h"
#endif
#if defined(USE_PF)
#include "pf/obsdrdr.h"
#endif
#if defined(USE_IPF)
#include "ipf/ipfrdr.h"
#endif
#if defined(USE_IPFW)
#include "ipfw/ipfwrdr.h"
#endif
#ifdef USE_MINIUPNPDCTL
#include <stdio.h>
#include <unistd.h>
#endif
#ifdef ENABLE_LEASEFILE
#include <sys/stat.h>
#endif

/* from <inttypes.h> */
#ifndef PRIu64
#define PRIu64 "llu"
#endif

/* proto_atoi() 
 * convert the string "UDP" or "TCP" to IPPROTO_UDP and IPPROTO_UDP */
static int
proto_atoi(const char * protocol)
{
	int proto = IPPROTO_TCP;
	if(strcmp(protocol, "UDP") == 0)
		proto = IPPROTO_UDP;
	return proto;
}

#ifdef ENABLE_LEASEFILE
static int lease_file_add( unsigned short eport, const char * iaddr, unsigned short iport, int proto, const char * desc)
{
	FILE * fd;

	if (lease_file == NULL) return 0;

	fd = fopen( lease_file, "a");
	if (fd==NULL) {
		syslog(LOG_ERR, "could not open lease file: %s", lease_file);
		return -1;
	}

	fprintf( fd, "%s:%hu:%s:%hu:%s\n",
	         ((proto==IPPROTO_TCP)?"TCP":"UDP"), eport, iaddr, iport, desc);
	fclose(fd);
	
	return 0;
}

static int lease_file_remove( unsigned short eport, int proto)
{
	FILE* fd, *fdt;
	int tmp;
	char buf[512];
	char str[32];
	char tmpfilename[128];
	int str_size, buf_size;


	if (lease_file == NULL) return 0;

	if (strlen( lease_file) + 7 > sizeof(tmpfilename)) {
		syslog(LOG_ERR, "Lease filename is too long");
		return -1;
	}

	strncpy( tmpfilename, lease_file, sizeof(tmpfilename) );
	strncat( tmpfilename, "XXXXXX", sizeof(tmpfilename) - strlen(tmpfilename));

	fd = fopen( lease_file, "r");
	if (fd==NULL) {
		return 0;
	}

	snprintf( str, sizeof(str), "%s:%u", ((proto==IPPROTO_TCP)?"TCP":"UDP"), eport);
	str_size = strlen(str);

	tmp = mkstemp(tmpfilename);
	if (tmp==-1) {
		fclose(fd);
		syslog(LOG_ERR, "could not open temporary lease file");
		return -1;
	}
	fchmod(tmp, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
	fdt = fdopen(tmp, "a");

	buf[sizeof(buf)-1] = 0;
	while( fgets( buf, sizeof(buf)-1, fd) != NULL) {
		buf_size = strlen(buf);

		if (buf_size < str_size || strncmp( str, buf, str_size)!=0) {
			fwrite(buf, buf_size, 1, fdt);
		}
	}
	fclose(fdt);
	fclose(fd);
	
	if (rename( tmpfilename, lease_file) < 0) {
		syslog(LOG_ERR, "could not rename temporary lease file to %s", lease_file);
		remove( tmpfilename);
	}
	
	return 0;
	
}

/* reload_from_lease_file()
 * read lease_file and add the rules contained
 */
int reload_from_lease_file()
{
	FILE * fd;
	char * p;
	unsigned short eport, iport;
	char * proto;
	char * iaddr;
	char * desc;
	char line[128];
	int r;

	if(!lease_file) return -1;
	fd = fopen( lease_file, "r");
	if (fd==NULL) {
		syslog(LOG_ERR, "could not open lease file: %s", lease_file);
		return -1;
	}
	if(unlink(lease_file) < 0) {
		syslog(LOG_WARNING, "could not unlink file %s : %m", lease_file);
	}

	while(fgets(line, sizeof(line), fd)) {
		syslog(LOG_DEBUG, "parsing lease file line '%s'", line);
		proto = line;
		p = strchr(line, ':');
		if(!p) {
			syslog(LOG_ERR, "unrecognized data in lease file");
			continue;
		}
		*(p++) = '\0';
		iaddr = strchr(p, ':');
		if(!iaddr) {
			syslog(LOG_ERR, "unrecognized data in lease file");
			continue;
		}
		*(iaddr++) = '\0';
		eport = (unsigned short)atoi(p);
		p = strchr(iaddr, ':');
		if(!p) {
			syslog(LOG_ERR, "unrecognized data in lease file");
			continue;
		}
		*(p++) = '\0';
		desc = strchr(p, ':');
		if(!desc) {
			syslog(LOG_ERR, "unrecognized data in lease file");
			continue;
		}
		*(desc++) = '\0';
		iport = (unsigned short)atoi(p);
		/* trim description */
		while(isspace(*desc))
			desc++;
		p = desc;
		while(*(p+1))
			p++;
		while(isspace(*p) && (p > desc))
			*(p--) = '\0';

		r = upnp_redirect(eport, iaddr, iport, proto, desc);
		if(r == -1) {
			syslog(LOG_ERR, "Failed to redirect %hu -> %s:%hu protocol %s",
			       eport, iaddr, iport, proto);
		} else if(r == -2) {
			/* Add the redirection again to the lease file */
			lease_file_add(eport, iaddr, iport, proto_atoi(proto), desc);
		}
	}
	fclose(fd);
	
	return 0;
}
#endif

/* upnp_redirect() 
 * calls OS/fw dependant implementation of the redirection.
 * protocol should be the string "TCP" or "UDP"
 * returns: 0 on success
 *          -1 failed to redirect
 *          -2 already redirected
 *          -3 permission check failed
 */
int
upnp_redirect(unsigned short eport, 
              const char * iaddr, unsigned short iport,
              const char * protocol, const char * desc)
{
	int proto, r;
	char iaddr_old[32];
	unsigned short iport_old;
	struct in_addr address;
	proto = proto_atoi(protocol);
	if(inet_aton(iaddr, &address) < 0) {
		syslog(LOG_ERR, "inet_aton(%s) : %m", iaddr);
		return -1;
	}

	if(!check_upnp_rule_against_permissions(upnppermlist, num_upnpperm,
	                                        eport, address, iport)) {
		syslog(LOG_INFO, "redirection permission check failed for "
		                 "%hu->%s:%hu %s", eport, iaddr, iport, protocol);
		return -3;
	}
	r = get_redirect_rule(ext_if_name, eport, proto,
	                      iaddr_old, sizeof(iaddr_old), &iport_old, 0, 0, 0, 0);
	if(r == 0) {
		/* if existing redirect rule matches redirect request return success
		 * xbox 360 does not keep track of the port it redirects and will
		 * redirect another port when receiving ConflictInMappingEntry */
		if(strcmp(iaddr,iaddr_old)==0 && iport==iport_old) {
			syslog(LOG_INFO, "ignoring redirect request as it matches existing redirect");
		} else {

			syslog(LOG_INFO, "port %hu protocol %s already redirected to %s:%hu",
				eport, protocol, iaddr_old, iport_old);
			return -2;
		}
	} else {
		syslog(LOG_INFO, "redirecting port %hu to %s:%hu protocol %s for: %s",
			eport, iaddr, iport, protocol, desc);			
		return upnp_redirect_internal(eport, iaddr, iport, proto, desc);
	}

	return 0;
}

int
upnp_redirect_internal(unsigned short eport,
                       const char * iaddr, unsigned short iport,
                       int proto, const char * desc)
{
	/*syslog(LOG_INFO, "redirecting port %hu to %s:%hu protocol %s for: %s",
		eport, iaddr, iport, protocol, desc);			*/
	if(add_redirect_rule2(ext_if_name, eport, iaddr, iport, proto, desc) < 0) {
		return -1;
	}

#ifdef ENABLE_LEASEFILE
	lease_file_add( eport, iaddr, iport, proto, desc);
#endif
/*	syslog(LOG_INFO, "creating pass rule to %s:%hu protocol %s for: %s",
		iaddr, iport, protocol, desc);*/
	if(add_filter_rule2(ext_if_name, iaddr, eport, iport, proto, desc) < 0) {
		/* clean up the redirect rule */
#if !defined(__linux__)
		delete_redirect_rule(ext_if_name, eport, proto);
#endif
		return -1;
	}
#ifdef ENABLE_EVENTS
	upnp_event_var_change_notify(EWanIPC);
#endif
	return 0;
}



int
upnp_get_redirection_infos(unsigned short eport, const char * protocol,
                           unsigned short * iport,
                           char * iaddr, int iaddrlen,
                           char * desc, int desclen)
{
	if(desc && (desclen > 0))
		desc[0] = '\0';
	return get_redirect_rule(ext_if_name, eport, proto_atoi(protocol),
	                         iaddr, iaddrlen, iport, desc, desclen, 0, 0);
}

int
upnp_get_redirection_infos_by_index(int index,
                                    unsigned short * eport, char * protocol,
                                    unsigned short * iport, 
                                    char * iaddr, int iaddrlen,
                                    char * desc, int desclen)
{
	/*char ifname[IFNAMSIZ];*/
	int proto = 0;

	if(desc && (desclen > 0))
		desc[0] = '\0';
	if(get_redirect_rule_by_index(index, 0/*ifname*/, eport, iaddr, iaddrlen,
	                              iport, &proto, desc, desclen, 0, 0) < 0)
		return -1;
	else
	{
		if(proto == IPPROTO_TCP)
			memcpy(protocol, "TCP", 4);
		else
			memcpy(protocol, "UDP", 4);
		return 0;
	}
}

int
_upnp_delete_redir(unsigned short eport, int proto)
{
	int r;
#if defined(__linux__)
	r = delete_redirect_and_filter_rules(eport, proto);
#else
	r = delete_redirect_rule(ext_if_name, eport, proto);
	delete_filter_rule(ext_if_name, eport, proto);
#endif
#ifdef ENABLE_LEASEFILE
	lease_file_remove( eport, proto);
#endif

#ifdef ENABLE_EVENTS
	upnp_event_var_change_notify(EWanIPC);
#endif
	return r;
}

int
upnp_delete_redirection(unsigned short eport, const char * protocol)
{
	syslog(LOG_INFO, "removing redirect rule port %hu %s", eport, protocol);
	return _upnp_delete_redir(eport, proto_atoi(protocol));
}

/* upnp_get_portmapping_number_of_entries()
 * TODO: improve this code */
int
upnp_get_portmapping_number_of_entries()
{
	int n = 0, r = 0;
	unsigned short eport, iport;
	char protocol[4], iaddr[32], desc[64];
	do {
		protocol[0] = '\0'; iaddr[0] = '\0'; desc[0] = '\0';
		r = upnp_get_redirection_infos_by_index(n, &eport, protocol, &iport,
		                                        iaddr, sizeof(iaddr),
		                                        desc, sizeof(desc) );
		n++;
	} while(r==0);
	return (n-1);
}

/* functions used to remove unused rules */
struct rule_state *
get_upnp_rules_state_list(int max_rules_number_target)
{
	/*char ifname[IFNAMSIZ];*/
	int proto;
	unsigned short iport;
	struct rule_state * tmp;
	struct rule_state * list = 0;
	int i = 0;
	/*ifname[0] = '\0';*/
	tmp = malloc(sizeof(struct rule_state));
	if(!tmp)
		return 0;
	while(get_redirect_rule_by_index(i, /*ifname*/0, &tmp->eport, 0, 0,
	                              &iport, &proto, 0, 0,
								  &tmp->packets, &tmp->bytes) >= 0)
	{
		tmp->proto = (short)proto;
		/* add tmp to list */
		tmp->next = list;
		list = tmp;
		/* prepare next iteration */
		i++;
		tmp = malloc(sizeof(struct rule_state));
		if(!tmp)
			break;
	}
	free(tmp);
	/* return empty list if not enough redirections */
	if(i<=max_rules_number_target)
		while(list)
		{
			tmp = list;
			list = tmp->next;
			free(tmp);
		}
	/* return list */
	return list;
}

void
remove_unused_rules(struct rule_state * list)
{
	char ifname[IFNAMSIZ];
	unsigned short iport;
	struct rule_state * tmp;
	u_int64_t packets;
	u_int64_t bytes;
	int n = 0;
	while(list)
	{
		/* remove the rule if no traffic has used it */
		if(get_redirect_rule(ifname, list->eport, list->proto,
	                         0, 0, &iport, 0, 0, &packets, &bytes) >= 0)
		{
			if(packets == list->packets && bytes == list->bytes)
			{
				_upnp_delete_redir(list->eport, list->proto);
				n++;
			}
		}
		tmp = list;
		list = tmp->next;
		free(tmp);
	}
	if(n>0)
		syslog(LOG_NOTICE, "removed %d unused rules", n);
}


/* stuff for miniupnpdctl */
#ifdef USE_MINIUPNPDCTL
void
write_ruleset_details(int s)
{
	char ifname[IFNAMSIZ];
	int proto = 0;
	unsigned short eport, iport;
	char desc[64];
	char iaddr[32];
	u_int64_t packets;
	u_int64_t bytes;
	int i = 0;
	char buffer[256];
	int n;
	ifname[0] = '\0';
	write(s, "Ruleset :\n", 10);
	while(get_redirect_rule_by_index(i, ifname, &eport, iaddr, sizeof(iaddr),
	                                 &iport, &proto, desc, sizeof(desc),
	                                 &packets, &bytes) >= 0)
	{
		n = snprintf(buffer, sizeof(buffer), "%2d %s %s %hu->%s:%hu "
		                                     "'%s' %" PRIu64 " %" PRIu64 "\n",
		                                     /*"'%s' %llu %llu\n",*/
		             i, ifname, proto==IPPROTO_TCP?"TCP":"UDP",
		             eport, iaddr, iport, desc, packets, bytes);
		write(s, buffer, n);
		i++;
	}
}
#endif