miniupnp/miniupnpd/upnpredirect.c

/* $Id: upnpredirect.c,v 1.93 2018/03/12 22:41:53 nanard Exp $ */
/* vim: tabstop=4 shiftwidth=4 noexpandtab
 * MiniUPnP project
 * http://miniupnp.free.fr/ or https://miniupnp.tuxfamily.org/
 * (c) 2006-2018 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 "macros.h"
#include "config.h"
#include "upnpredirect.h"
#include "upnpglobalvars.h"
#include "upnpevents.h"
#include "portinuse.h"
#include "upnputils.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(strcasecmp(protocol, "UDP") == 0)
		proto = IPPROTO_UDP;
#ifdef IPPROTO_UDPLITE
	else if(strcasecmp(protocol, "UDPLITE") == 0)
		proto = IPPROTO_UDPLITE;
#endif /* IPPROTO_UDPLITE */
	return proto;
}

/* proto_itoa()
 * convert IPPROTO_UDP, IPPROTO_UDP, etc. to "UDP", "TCP" */
static const char *
proto_itoa(int proto)
{
	const char * protocol;
	switch(proto) {
	case IPPROTO_UDP:
		protocol = "UDP";
		break;
	case IPPROTO_TCP:
		protocol = "TCP";
		break;
#ifdef IPPROTO_UDPLITE
	case IPPROTO_UDPLITE:
		protocol = "UDPLITE";
		break;
#endif /* IPPROTO_UDPLITE */
	default:
		protocol = "*UNKNOWN*";
	}
	return protocol;
}

#ifdef ENABLE_LEASEFILE
static int
lease_file_add(unsigned short eport,
               const char * iaddr,
               unsigned short iport,
               int proto,
               const char * desc,
               unsigned int timestamp)
{
	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:%u:%s\n",
	        proto_itoa(proto), eport, iaddr, iport,
	        timestamp, 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_itoa(proto), 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 * rhost;
	unsigned int leaseduration;
	unsigned int timestamp;
	time_t current_time;
	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);
	}

	current_time = upnp_time();
	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';
		iport = (unsigned short)atoi(p);
		p = strchr(p, ':');
		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';
		/*timestamp = (unsigned int)atoi(p);*/
		timestamp = (unsigned int)strtoul(p, NULL, 10);
		/* trim description */
		while(isspace(*desc))
			desc++;
		p = desc;
		while(*(p+1))
			p++;
		while(isspace(*p) && (p > desc))
			*(p--) = '\0';

		if(timestamp > 0) {
			if(timestamp <= (unsigned int)current_time) {
				syslog(LOG_NOTICE, "already expired lease in lease file");
				continue;
			} else {
				leaseduration = timestamp - current_time;
			}
		} else {
			leaseduration = 0;	/* default value */
		}
		rhost = NULL;
		r = upnp_redirect(rhost, eport, iaddr, iport, proto, desc, leaseduration);
		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, timestamp);
		}
	}
	fclose(fd);

	return 0;
}
#endif

/* upnp_redirect()
 * calls OS/fw dependent 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
 *          -4 already redirected (other mechanism)
 */
int
upnp_redirect(const char * rhost, unsigned short eport,
              const char * iaddr, unsigned short iport,
              const char * protocol, const char * desc,
              unsigned int leaseduration)
{
	int proto, r;
	char iaddr_old[32];
	char rhost_old[32];
	unsigned short iport_old;
	struct in_addr address;
	unsigned int timestamp;

	proto = proto_atoi(protocol);
	if(inet_aton(iaddr, &address) <= 0) {
		syslog(LOG_ERR, "inet_aton(%s) FAILED", 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;
	}
	/* IGDv1 (WANIPConnection:1 Service Template Version 1.01 / Nov 12, 2001)
	 * - 2.2.20.PortMappingDescription :
	 *  Overwriting Previous / Existing Port Mappings:
	 * If the RemoteHost, ExternalPort, PortMappingProtocol and InternalClient
	 * are exactly the same as an existing mapping, the existing mapping values
	 * for InternalPort, PortMappingDescription, PortMappingEnabled and
	 * PortMappingLeaseDuration are overwritten.
	 *  Rejecting a New Port Mapping:
	 * In cases where the RemoteHost, ExternalPort and PortMappingProtocol
	 * are the same as an existing mapping, but the InternalClient is
	 * different, the action is rejected with an appropriate error.
	 *  Add or Reject New Port Mapping behavior based on vendor implementation:
	 * In cases where the ExternalPort, PortMappingProtocol and InternalClient
	 * are the same, but RemoteHost is different, the vendor can choose to
	 * support both mappings simultaneously, or reject the second mapping
	 * with an appropriate error.
	 *
	 * - 2.4.16.AddPortMapping
	 * This action creates a new port mapping or overwrites an existing
	 * mapping with the same internal client. If the ExternalPort and
	 * PortMappingProtocol pair is already mapped to another internal client,
	 * an error is returned.
	 *
	 * IGDv2 (WANIPConnection:2 Service Standardized DCP (SDCP) Sep 10, 2010)
	 * Protocol ExternalPort RemoteHost InternalClient Result
	 *     =         =           ≠           ≠         Failure
	 *     =         =           ≠           =         Failure or success
	 *                                                 (vendor specific)
	 *     =         =           =           ≠         Failure
	 *     =         =           =           =         Success (overwrite)
	 */
	rhost_old[0] = '\0';
	r = get_redirect_rule(ext_if_name, eport, proto,
	                      iaddr_old, sizeof(iaddr_old), &iport_old, 0, 0,
	                      rhost_old, sizeof(rhost_old),
	                      &timestamp, 0, 0);
	if(r == 0) {
		if(strcmp(iaddr, iaddr_old)==0 &&
		   ((rhost == NULL && rhost_old[0]=='\0') ||
		    (rhost && (strcmp(rhost, "*") == 0) && rhost_old[0]=='\0') ||
		    (rhost && (strcmp(rhost, rhost_old) == 0)))) {
			syslog(LOG_INFO, "updating existing port mapping %hu %s (rhost '%s') => %s:%hu",
				eport, protocol, rhost_old, iaddr_old, iport_old);
			timestamp = (leaseduration > 0) ? upnp_time() + leaseduration : 0;
			if(iport != iport_old) {
				r = update_portmapping(ext_if_name, eport, proto, iport, desc, timestamp);
			} else {
				r = update_portmapping_desc_timestamp(ext_if_name, eport, proto, desc, timestamp);
			}
#ifdef ENABLE_LEASEFILE
			if(r == 0) {
				lease_file_remove(eport, proto);
				lease_file_add(eport, iaddr, iport, proto, desc, timestamp);
			}
#endif /* ENABLE_LEASEFILE */
			return r;
		} else {
			syslog(LOG_INFO, "port %hu %s (rhost '%s') already redirected to %s:%hu",
				eport, protocol, rhost_old, iaddr_old, iport_old);
			return -2;
		}
#ifdef CHECK_PORTINUSE
	} else if (port_in_use(ext_if_name, eport, proto, iaddr, iport) > 0) {
		syslog(LOG_INFO, "port %hu protocol %s already in use",
		       eport, protocol);
		return -4;
#endif /* CHECK_PORTINUSE */
	} else {
		timestamp = (leaseduration > 0) ? upnp_time() + leaseduration : 0;
		syslog(LOG_INFO, "redirecting port %hu to %s:%hu protocol %s for: %s",
			eport, iaddr, iport, protocol, desc);
		return upnp_redirect_internal(rhost, eport, iaddr, iport, proto,
		                              desc, timestamp);
	}
}

int
upnp_redirect_internal(const char * rhost, unsigned short eport,
                       const char * iaddr, unsigned short iport,
                       int proto, const char * desc,
                       unsigned int timestamp)
{
	/*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, rhost, eport, iaddr, iport, proto,
	                      desc, timestamp) < 0) {
		return -1;
	}

#ifdef ENABLE_LEASEFILE
	lease_file_add( eport, iaddr, iport, proto, desc, timestamp);
#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, rhost, 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;
	}
	if(timestamp > 0) {
		if(!nextruletoclean_timestamp || (timestamp < nextruletoclean_timestamp))
			nextruletoclean_timestamp = timestamp;
	}
#ifdef ENABLE_EVENTS
	/* the number of port mappings changed, we must
	 * inform the subscribers */
	upnp_event_var_change_notify(EWanIPC);
#endif
	return 0;
}



/* Firewall independent code which call the FW dependent code. */
int
upnp_get_redirection_infos(unsigned short eport, const char * protocol,
                           unsigned short * iport,
                           char * iaddr, int iaddrlen,
                           char * desc, int desclen,
                           char * rhost, int rhostlen,
                           unsigned int * leaseduration)
{
	int r;
	unsigned int timestamp;
	time_t current_time;

	if(desc && (desclen > 0))
		desc[0] = '\0';
	if(rhost && (rhostlen > 0))
		rhost[0] = '\0';
	r = get_redirect_rule(ext_if_name, eport, proto_atoi(protocol),
	                      iaddr, iaddrlen, iport, desc, desclen,
	                      rhost, rhostlen, &timestamp,
	                      0, 0);
	if(r == 0 &&
	   timestamp > 0 &&
	   timestamp > (unsigned int)(current_time = upnp_time())) {
		*leaseduration = timestamp - current_time;
	} else {
		*leaseduration = 0;
	}
	return r;
}

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 * rhost, int rhostlen,
                                    unsigned int * leaseduration)
{
	/*char ifname[IFNAMSIZ];*/
	int proto = 0;
	unsigned int timestamp;
	time_t current_time;

	if(desc && (desclen > 0))
		desc[0] = '\0';
	if(rhost && (rhostlen > 0))
		rhost[0] = '\0';
	if(get_redirect_rule_by_index(index, 0/*ifname*/, eport, iaddr, iaddrlen,
	                              iport, &proto, desc, desclen,
	                              rhost, rhostlen, &timestamp,
	                              0, 0) < 0)
		return -1;
	else
	{
		current_time = upnp_time();
		*leaseduration = (timestamp > (unsigned int)current_time)
		                 ? (timestamp - current_time)
		                 : 0;
		if(proto == IPPROTO_TCP)
			memcpy(protocol, "TCP", 4);
#ifdef IPPROTO_UDPLITE
		else if(proto == IPPROTO_UDPLITE)
			memcpy(protocol, "UDPLITE", 8);
#endif /* IPPROTO_UDPLITE */
		else
			memcpy(protocol, "UDP", 4);
		return 0;
	}
}

/* called from natpmp.c too */
int
_upnp_delete_redir(unsigned short eport, int proto)
{
	int r;
#if defined(__linux__)
	r = delete_redirect_and_filter_rules(eport, proto);
#elif defined(USE_PF)
	r = delete_redirect_and_filter_rules(ext_if_name, 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], rhost[32];
	unsigned int leaseduration;
	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),
		                                        rhost, sizeof(rhost),
		                                        &leaseduration);
		n++;
	} while(r==0);
	return (n-1);
}

/* functions used to remove unused rules
 * As a side effect, delete expired rules (based on LeaseDuration) */
struct rule_state *
get_upnp_rules_state_list(int max_rules_number_target)
{
	/*char ifname[IFNAMSIZ];*/
	int proto;
	unsigned short iport;
	unsigned int timestamp;
	struct rule_state * tmp;
	struct rule_state * list = 0;
	struct rule_state * * p;
	int i = 0;
	time_t current_time;

	/*ifname[0] = '\0';*/
	tmp = malloc(sizeof(struct rule_state));
	if(!tmp)
		return 0;
	current_time = upnp_time();
	nextruletoclean_timestamp = 0;
	while(get_redirect_rule_by_index(i, /*ifname*/0, &tmp->eport, 0, 0,
	                              &iport, &proto, 0, 0, 0,0, &timestamp,
								  &tmp->packets, &tmp->bytes) >= 0)
	{
		tmp->to_remove = 0;
		if(timestamp > 0) {
			/* need to remove this port mapping ? */
			if(timestamp <= (unsigned int)current_time)
				tmp->to_remove = 1;
			else if((nextruletoclean_timestamp <= (unsigned int)current_time)
			       || (timestamp < nextruletoclean_timestamp))
				nextruletoclean_timestamp = timestamp;
		}
		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;
	}
#ifdef PCP_PEER
	i=0;
	while(get_peer_rule_by_index(i, /*ifname*/0, &tmp->eport, 0, 0,
		                              &iport, &proto, 0, 0, 0,0,0, &timestamp,
									  &tmp->packets, &tmp->bytes) >= 0)
	{
		tmp->to_remove = 0;
		if(timestamp > 0) {
			/* need to remove this port mapping ? */
			if(timestamp <= (unsigned int)current_time)
				tmp->to_remove = 1;
			else if((nextruletoclean_timestamp <= (unsigned int)current_time)
				   || (timestamp < nextruletoclean_timestamp))
				nextruletoclean_timestamp = timestamp;
		}
		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;
	}
#endif
	free(tmp);
	/* remove the redirections that need to be removed */
	for(p = &list, tmp = list; tmp; tmp = *p)
	{
		if(tmp->to_remove)
		{
			syslog(LOG_NOTICE, "remove port mapping %hu %s because it has expired",
			       tmp->eport, proto_itoa(tmp->proto));
			_upnp_delete_redir(tmp->eport, tmp->proto);
			*p = tmp->next;
			free(tmp);
			i--;
		} else {
			p = &(tmp->next);
		}
	}
	/* 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;
	unsigned int timestamp;
	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, 0, 0, &timestamp,
		                     &packets, &bytes) >= 0)
		{
			if(packets == list->packets && bytes == list->bytes)
			{
				syslog(LOG_DEBUG, "removing unused mapping %hu %s : still "
				       "%" PRIu64 "packets %" PRIu64 "bytes",
				       list->eport, proto_itoa(list->proto),
				       packets, 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);
}

/* upnp_get_portmappings_in_range()
 * return a list of all "external" ports for which a port
 * mapping exists */
unsigned short *
upnp_get_portmappings_in_range(unsigned short startport,
                               unsigned short endport,
                               const char * protocol,
                               unsigned int * number)
{
	int proto;
	proto = proto_atoi(protocol);
	if(!number)
		return NULL;
	return get_portmappings_in_range(startport, endport, proto, number);
}

/* stuff for miniupnpdctl */
#ifdef USE_MINIUPNPDCTL
void
write_ruleset_details(int s)
{
	int proto = 0;
	unsigned short eport, iport;
	char desc[64];
	char iaddr[32];
	char rhost[32];
	unsigned int timestamp;
	u_int64_t packets;
	u_int64_t bytes;
	int i = 0;
	char buffer[256];
	int n;

	write(s, "Ruleset :\n", 10);
	while(get_redirect_rule_by_index(i, 0/*ifname*/, &eport, iaddr, sizeof(iaddr),
	                                 &iport, &proto, desc, sizeof(desc),
	                                 rhost, sizeof(rhost),
	                                 &timestamp,
	                                 &packets, &bytes) >= 0)
	{
		n = snprintf(buffer, sizeof(buffer),
		             "%2d %s %s:%hu->%s:%hu "
		             "'%s' %u %" PRIu64 " %" PRIu64 "\n",
		             /*"'%s' %llu %llu\n",*/
		             i, proto_itoa(proto), rhost,
		             eport, iaddr, iport, desc, timestamp, packets, bytes);
		write(s, buffer, n);
		i++;
	}
}
#endif