canohost.c - platform/external/openssh - Gitiles

 /* $OpenBSD: canohost.c,v 1.61 2006/08/03 03:34:41 deraadt Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  * Functions for returning the canonical host name of the remote site.
  *
  * As far as I am concerned, the code I have written for this software
  * can be used freely for any purpose.  Any derived versions of this
  * software must be clearly marked as such, and if the derived work is
  * incompatible with the protocol description in the RFC file, it must be
  * called by a name other than "ssh" or "Secure Shell".
  */

 #include "includes.h"

 #include <sys/types.h>
 #include <sys/socket.h>

 #include <netinet/in.h>
 #include <arpa/inet.h>

 #include <ctype.h>
 #include <errno.h>
 #include <netdb.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>

 #include "xmalloc.h"
 #include "packet.h"
 #include "log.h"
 #include "canohost.h"

 static void check_ip_options(int, char *);

 /*
  * Return the canonical name of the host at the other end of the socket. The
  * caller should free the returned string with xfree.
  */

 static char *
 get_remote_hostname(int sock, int use_dns)
 {
 	struct sockaddr_storage from;
 	int i;
 	socklen_t fromlen;
 	struct addrinfo hints, *ai, *aitop;
 	char name[NI_MAXHOST], ntop[NI_MAXHOST], ntop2[NI_MAXHOST];

 	/* Get IP address of client. */
 	fromlen = sizeof(from);
 	memset(&from, 0, sizeof(from));
 	if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
 		debug("getpeername failed: %.100s", strerror(errno));
 		cleanup_exit(255);
 	}

 	if (from.ss_family == AF_INET)
 		check_ip_options(sock, ntop);

 	ipv64_normalise_mapped(&from, &fromlen);

 	if (from.ss_family == AF_INET6)
 		fromlen = sizeof(struct sockaddr_in6);

 	if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
 	    NULL, 0, NI_NUMERICHOST) != 0)
 		fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed");

 	if (!use_dns)
 		return xstrdup(ntop);

 	debug3("Trying to reverse map address %.100s.", ntop);
 	/* Map the IP address to a host name. */
 	if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
 	    NULL, 0, NI_NAMEREQD) != 0) {
 		/* Host name not found.  Use ip address. */
 		return xstrdup(ntop);
 	}

 	/*
 	 * if reverse lookup result looks like a numeric hostname,
 	 * someone is trying to trick us by PTR record like following:
 	 *	1.1.1.10.in-addr.arpa.	IN PTR	2.3.4.5
 	 */
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
 	hints.ai_flags = AI_NUMERICHOST;
 	if (getaddrinfo(name, "0", &hints, &ai) == 0) {
 		logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
 		    name, ntop);
 		freeaddrinfo(ai);
 		return xstrdup(ntop);
 	}

 	/*
 	 * Convert it to all lowercase (which is expected by the rest
 	 * of this software).
 	 */
 	for (i = 0; name[i]; i++)
 		if (isupper(name[i]))
 			name[i] = (char)tolower(name[i]);
 	/*
 	 * Map it back to an IP address and check that the given
 	 * address actually is an address of this host.  This is
 	 * necessary because anyone with access to a name server can
 	 * define arbitrary names for an IP address. Mapping from
 	 * name to IP address can be trusted better (but can still be
 	 * fooled if the intruder has access to the name server of
 	 * the domain).
 	 */
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = from.ss_family;
 	hints.ai_socktype = SOCK_STREAM;
 	if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
 		logit("reverse mapping checking getaddrinfo for %.700s "
 		    "[%s] failed - POSSIBLE BREAK-IN ATTEMPT!", name, ntop);
 		return xstrdup(ntop);
 	}
 	/* Look for the address from the list of addresses. */
 	for (ai = aitop; ai; ai = ai->ai_next) {
 		if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
 		    sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
 		    (strcmp(ntop, ntop2) == 0))
 				break;
 	}
 	freeaddrinfo(aitop);
 	/* If we reached the end of the list, the address was not there. */
 	if (!ai) {
 		/* Address not found for the host name. */
 		logit("Address %.100s maps to %.600s, but this does not "
 		    "map back to the address - POSSIBLE BREAK-IN ATTEMPT!",
 		    ntop, name);
 		return xstrdup(ntop);
 	}
 	return xstrdup(name);
 }

 /*
  * If IP options are supported, make sure there are none (log and
  * disconnect them if any are found).  Basically we are worried about
  * source routing; it can be used to pretend you are somebody
  * (ip-address) you are not. That itself may be "almost acceptable"
  * under certain circumstances, but rhosts autentication is useless
  * if source routing is accepted. Notice also that if we just dropped
  * source routing here, the other side could use IP spoofing to do
  * rest of the interaction and could still bypass security.  So we
  * exit here if we detect any IP options.
  */
 /* IPv4 only */
 static void
 check_ip_options(int sock, char *ipaddr)
 {
 #ifdef IP_OPTIONS
 	u_char options[200];
 	char text[sizeof(options) * 3 + 1];
 	socklen_t option_size;
 	u_int i;
 	int ipproto;
 	struct protoent *ip;

 	if ((ip = getprotobyname("ip")) != NULL)
 		ipproto = ip->p_proto;
 	else
 		ipproto = IPPROTO_IP;
 	option_size = sizeof(options);
 	if (getsockopt(sock, ipproto, IP_OPTIONS, options,
 	    &option_size) >= 0 && option_size != 0) {
 		text[0] = '\0';
 		for (i = 0; i < option_size; i++)
 			snprintf(text + i*3, sizeof(text) - i*3,
 			    " %2.2x", options[i]);
 		fatal("Connection from %.100s with IP options:%.800s",
 		    ipaddr, text);
 	}
 #endif /* IP_OPTIONS */
 }

 void
 ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
 {
 	struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr;
 	struct sockaddr_in *a4 = (struct sockaddr_in *)addr;
 	struct in_addr inaddr;
 	u_int16_t port;

 	if (addr->ss_family != AF_INET6 ||
 	    !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))
 		return;

 	debug3("Normalising mapped IPv4 in IPv6 address");

 	memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));
 	port = a6->sin6_port;

 	memset(addr, 0, sizeof(*a4));

 	a4->sin_family = AF_INET;
 	*len = sizeof(*a4);
 	memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr));
 	a4->sin_port = port;
 }

 /*
  * Return the canonical name of the host in the other side of the current
  * connection.  The host name is cached, so it is efficient to call this
  * several times.
  */

 const char *
 get_canonical_hostname(int use_dns)
 {
 	char *host;
 	static char *canonical_host_name = NULL;
 	static char *remote_ip = NULL;

 	/* Check if we have previously retrieved name with same option. */
 	if (use_dns && canonical_host_name != NULL)
 		return canonical_host_name;
 	if (!use_dns && remote_ip != NULL)
 		return remote_ip;

 	/* Get the real hostname if socket; otherwise return UNKNOWN. */
 	if (packet_connection_is_on_socket())
 		host = get_remote_hostname(packet_get_connection_in(), use_dns);
 	else
 		host = "UNKNOWN";

 	if (use_dns)
 		canonical_host_name = host;
 	else
 		remote_ip = host;
 	return host;
 }

 /*
  * Returns the local/remote IP-address/hostname of socket as a string.
  * The returned string must be freed.
  */
 static char *
 get_socket_address(int sock, int remote, int flags)
 {
 	struct sockaddr_storage addr;
 	socklen_t addrlen;
 	char ntop[NI_MAXHOST];
 	int r;

 	/* Get IP address of client. */
 	addrlen = sizeof(addr);
 	memset(&addr, 0, sizeof(addr));

 	if (remote) {
 		if (getpeername(sock, (struct sockaddr *)&addr, &addrlen)
 		    < 0)
 			return NULL;
 	} else {
 		if (getsockname(sock, (struct sockaddr *)&addr, &addrlen)
 		    < 0)
 			return NULL;
 	}

 	/* Work around Linux IPv6 weirdness */
 	if (addr.ss_family == AF_INET6)
 		addrlen = sizeof(struct sockaddr_in6);

 	ipv64_normalise_mapped(&addr, &addrlen);

 	/* Get the address in ascii. */
 	if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,
 	    sizeof(ntop), NULL, 0, flags)) != 0) {
 		error("get_socket_address: getnameinfo %d failed: %s", flags,
 		    r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
 		return NULL;
 	}
 	return xstrdup(ntop);
 }

 char *
 get_peer_ipaddr(int sock)
 {
 	char *p;

 	if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
 		return p;
 	return xstrdup("UNKNOWN");
 }

 char *
 get_local_ipaddr(int sock)
 {
 	char *p;

 	if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
 		return p;
 	return xstrdup("UNKNOWN");
 }

 char *
 get_local_name(int sock)
 {
 	return get_socket_address(sock, 0, NI_NAMEREQD);
 }

 /*
  * Returns the IP-address of the remote host as a string.  The returned
  * string must not be freed.
  */

 const char *
 get_remote_ipaddr(void)
 {
 	static char *canonical_host_ip = NULL;

 	/* Check whether we have cached the ipaddr. */
 	if (canonical_host_ip == NULL) {
 		if (packet_connection_is_on_socket()) {
 			canonical_host_ip =
 			    get_peer_ipaddr(packet_get_connection_in());
 			if (canonical_host_ip == NULL)
 				cleanup_exit(255);
 		} else {
 			/* If not on socket, return UNKNOWN. */
 			canonical_host_ip = xstrdup("UNKNOWN");
 		}
 	}
 	return canonical_host_ip;
 }

 const char *
 get_remote_name_or_ip(u_int utmp_len, int use_dns)
 {
 	static const char *remote = "";
 	if (utmp_len > 0)
 		remote = get_canonical_hostname(use_dns);
 	if (utmp_len == 0 || strlen(remote) > utmp_len)
 		remote = get_remote_ipaddr();
 	return remote;
 }

 /* Returns the local/remote port for the socket. */

 static int
 get_sock_port(int sock, int local)
 {
 	struct sockaddr_storage from;
 	socklen_t fromlen;
 	char strport[NI_MAXSERV];
 	int r;

 	/* Get IP address of client. */
 	fromlen = sizeof(from);
 	memset(&from, 0, sizeof(from));
 	if (local) {
 		if (getsockname(sock, (struct sockaddr *)&from, &fromlen) < 0) {
 			error("getsockname failed: %.100s", strerror(errno));
 			return 0;
 		}
 	} else {
 		if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
 			debug("getpeername failed: %.100s", strerror(errno));
 			return -1;
 		}
 	}

 	/* Work around Linux IPv6 weirdness */
 	if (from.ss_family == AF_INET6)
 		fromlen = sizeof(struct sockaddr_in6);

 	/* Return port number. */
 	if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
 	    strport, sizeof(strport), NI_NUMERICSERV)) != 0)
 		fatal("get_sock_port: getnameinfo NI_NUMERICSERV failed: %s",
 		    r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
 	return atoi(strport);
 }

 /* Returns remote/local port number for the current connection. */

 static int
 get_port(int local)
 {
 	/*
 	 * If the connection is not a socket, return 65535.  This is
 	 * intentionally chosen to be an unprivileged port number.
 	 */
 	if (!packet_connection_is_on_socket())
 		return 65535;

 	/* Get socket and return the port number. */
 	return get_sock_port(packet_get_connection_in(), local);
 }

 int
 get_peer_port(int sock)
 {
 	return get_sock_port(sock, 0);
 }

 int
 get_remote_port(void)
 {
 	static int port = -1;

 	/* Cache to avoid getpeername() on a dead connection */
 	if (port == -1)
 		port = get_port(0);

 	return port;
 }

 int
 get_local_port(void)
 {
 	return get_port(1);
 }
	/* $OpenBSD: canohost.c,v 1.61 2006/08/03 03:34:41 deraadt Exp $ */
	/*
	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	* All rights reserved
	* Functions for returning the canonical host name of the remote site.
	*
	* As far as I am concerned, the code I have written for this software
	* can be used freely for any purpose. Any derived versions of this
	* software must be clearly marked as such, and if the derived work is
	* incompatible with the protocol description in the RFC file, it must be
	* called by a name other than "ssh" or "Secure Shell".
	*/

	#include "includes.h"

	#include <sys/types.h>
	#include <sys/socket.h>

	#include <netinet/in.h>
	#include <arpa/inet.h>

	#include <ctype.h>
	#include <errno.h>
	#include <netdb.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <stdarg.h>

	#include "xmalloc.h"
	#include "packet.h"
	#include "log.h"
	#include "canohost.h"

	static void check_ip_options(int, char *);

	/*
	* Return the canonical name of the host at the other end of the socket. The
	* caller should free the returned string with xfree.
	*/

	static char *
	get_remote_hostname(int sock, int use_dns)
	{
	struct sockaddr_storage from;
	int i;
	socklen_t fromlen;
	struct addrinfo hints, ai, aitop;
	char name[NI_MAXHOST], ntop[NI_MAXHOST], ntop2[NI_MAXHOST];

	/* Get IP address of client. */
	fromlen = sizeof(from);
	memset(&from, 0, sizeof(from));
	if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
	debug("getpeername failed: %.100s", strerror(errno));
	cleanup_exit(255);
	}

	if (from.ss_family == AF_INET)
	check_ip_options(sock, ntop);

	ipv64_normalise_mapped(&from, &fromlen);

	if (from.ss_family == AF_INET6)
	fromlen = sizeof(struct sockaddr_in6);

	if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
	NULL, 0, NI_NUMERICHOST) != 0)
	fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed");

	if (!use_dns)
	return xstrdup(ntop);

	debug3("Trying to reverse map address %.100s.", ntop);
	/* Map the IP address to a host name. */
	if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
	NULL, 0, NI_NAMEREQD) != 0) {
	/* Host name not found. Use ip address. */
	return xstrdup(ntop);
	}

	/*
	* if reverse lookup result looks like a numeric hostname,
	* someone is trying to trick us by PTR record like following:
	* 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
	*/
	memset(&hints, 0, sizeof(hints));
	hints.ai_socktype = SOCK_DGRAM; /dummy/
	hints.ai_flags = AI_NUMERICHOST;
	if (getaddrinfo(name, "0", &hints, &ai) == 0) {
	logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
	name, ntop);
	freeaddrinfo(ai);
	return xstrdup(ntop);
	}

	/*
	* Convert it to all lowercase (which is expected by the rest
	* of this software).
	*/
	for (i = 0; name[i]; i++)
	if (isupper(name[i]))
	name[i] = (char)tolower(name[i]);
	/*
	* Map it back to an IP address and check that the given
	* address actually is an address of this host. This is
	* necessary because anyone with access to a name server can
	* define arbitrary names for an IP address. Mapping from
	* name to IP address can be trusted better (but can still be
	* fooled if the intruder has access to the name server of
	* the domain).
	*/
	memset(&hints, 0, sizeof(hints));
	hints.ai_family = from.ss_family;
	hints.ai_socktype = SOCK_STREAM;
	if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
	logit("reverse mapping checking getaddrinfo for %.700s "
	"[%s] failed - POSSIBLE BREAK-IN ATTEMPT!", name, ntop);
	return xstrdup(ntop);
	}
	/* Look for the address from the list of addresses. */
	for (ai = aitop; ai; ai = ai->ai_next) {
	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
	sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
	(strcmp(ntop, ntop2) == 0))
	break;
	}
	freeaddrinfo(aitop);
	/* If we reached the end of the list, the address was not there. */
	if (!ai) {
	/* Address not found for the host name. */
	logit("Address %.100s maps to %.600s, but this does not "
	"map back to the address - POSSIBLE BREAK-IN ATTEMPT!",
	ntop, name);
	return xstrdup(ntop);
	}
	return xstrdup(name);
	}

	/*
	* If IP options are supported, make sure there are none (log and
	* disconnect them if any are found). Basically we are worried about
	* source routing; it can be used to pretend you are somebody
	* (ip-address) you are not. That itself may be "almost acceptable"
	* under certain circumstances, but rhosts autentication is useless
	* if source routing is accepted. Notice also that if we just dropped
	* source routing here, the other side could use IP spoofing to do
	* rest of the interaction and could still bypass security. So we
	* exit here if we detect any IP options.
	*/
	/* IPv4 only */
	static void
	check_ip_options(int sock, char *ipaddr)
	{
	#ifdef IP_OPTIONS
	u_char options[200];
	char text[sizeof(options) * 3 + 1];
	socklen_t option_size;
	u_int i;
	int ipproto;
	struct protoent *ip;

	if ((ip = getprotobyname("ip")) != NULL)
	ipproto = ip->p_proto;
	else
	ipproto = IPPROTO_IP;
	option_size = sizeof(options);
	if (getsockopt(sock, ipproto, IP_OPTIONS, options,
	&option_size) >= 0 && option_size != 0) {
	text[0] = '\0';
	for (i = 0; i < option_size; i++)
	snprintf(text + i3, sizeof(text) - i3,
	" %2.2x", options[i]);
	fatal("Connection from %.100s with IP options:%.800s",
	ipaddr, text);
	}
	#endif /* IP_OPTIONS */
	}

	void
	ipv64_normalise_mapped(struct sockaddr_storage addr, socklen_t len)
	{
	struct sockaddr_in6 a6 = (struct sockaddr_in6 )addr;
	struct sockaddr_in a4 = (struct sockaddr_in )addr;
	struct in_addr inaddr;
	u_int16_t port;

	if (addr->ss_family != AF_INET6 \|\|
	!IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))
	return;

	debug3("Normalising mapped IPv4 in IPv6 address");

	memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));
	port = a6->sin6_port;

	memset(addr, 0, sizeof(*a4));

	a4->sin_family = AF_INET;
	len = sizeof(a4);
	memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr));
	a4->sin_port = port;
	}

	/*
	* Return the canonical name of the host in the other side of the current
	* connection. The host name is cached, so it is efficient to call this
	* several times.
	*/

	const char *
	get_canonical_hostname(int use_dns)
	{
	char *host;
	static char *canonical_host_name = NULL;
	static char *remote_ip = NULL;

	/* Check if we have previously retrieved name with same option. */
	if (use_dns && canonical_host_name != NULL)
	return canonical_host_name;
	if (!use_dns && remote_ip != NULL)
	return remote_ip;

	/* Get the real hostname if socket; otherwise return UNKNOWN. */
	if (packet_connection_is_on_socket())
	host = get_remote_hostname(packet_get_connection_in(), use_dns);
	else
	host = "UNKNOWN";

	if (use_dns)
	canonical_host_name = host;
	else
	remote_ip = host;
	return host;
	}

	/*
	* Returns the local/remote IP-address/hostname of socket as a string.
	* The returned string must be freed.
	*/
	static char *
	get_socket_address(int sock, int remote, int flags)
	{
	struct sockaddr_storage addr;
	socklen_t addrlen;
	char ntop[NI_MAXHOST];
	int r;

	/* Get IP address of client. */
	addrlen = sizeof(addr);
	memset(&addr, 0, sizeof(addr));

	if (remote) {
	if (getpeername(sock, (struct sockaddr *)&addr, &addrlen)
	< 0)
	return NULL;
	} else {
	if (getsockname(sock, (struct sockaddr *)&addr, &addrlen)
	< 0)
	return NULL;
	}

	/* Work around Linux IPv6 weirdness */
	if (addr.ss_family == AF_INET6)
	addrlen = sizeof(struct sockaddr_in6);

	ipv64_normalise_mapped(&addr, &addrlen);

	/* Get the address in ascii. */
	if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,
	sizeof(ntop), NULL, 0, flags)) != 0) {
	error("get_socket_address: getnameinfo %d failed: %s", flags,
	r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
	return NULL;
	}
	return xstrdup(ntop);
	}

	char *
	get_peer_ipaddr(int sock)
	{
	char *p;

	if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
	return p;
	return xstrdup("UNKNOWN");
	}

	char *
	get_local_ipaddr(int sock)
	{
	char *p;

	if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
	return p;
	return xstrdup("UNKNOWN");
	}

	char *
	get_local_name(int sock)
	{
	return get_socket_address(sock, 0, NI_NAMEREQD);
	}

	/*
	* Returns the IP-address of the remote host as a string. The returned
	* string must not be freed.
	*/

	const char *
	get_remote_ipaddr(void)
	{
	static char *canonical_host_ip = NULL;

	/* Check whether we have cached the ipaddr. */
	if (canonical_host_ip == NULL) {
	if (packet_connection_is_on_socket()) {
	canonical_host_ip =
	get_peer_ipaddr(packet_get_connection_in());
	if (canonical_host_ip == NULL)
	cleanup_exit(255);
	} else {
	/* If not on socket, return UNKNOWN. */
	canonical_host_ip = xstrdup("UNKNOWN");
	}
	}
	return canonical_host_ip;
	}

	const char *
	get_remote_name_or_ip(u_int utmp_len, int use_dns)
	{
	static const char *remote = "";
	if (utmp_len > 0)
	remote = get_canonical_hostname(use_dns);
	if (utmp_len == 0 \|\| strlen(remote) > utmp_len)
	remote = get_remote_ipaddr();
	return remote;
	}

	/* Returns the local/remote port for the socket. */

	static int
	get_sock_port(int sock, int local)
	{
	struct sockaddr_storage from;
	socklen_t fromlen;
	char strport[NI_MAXSERV];
	int r;

	/* Get IP address of client. */
	fromlen = sizeof(from);
	memset(&from, 0, sizeof(from));
	if (local) {
	if (getsockname(sock, (struct sockaddr *)&from, &fromlen) < 0) {
	error("getsockname failed: %.100s", strerror(errno));
	return 0;
	}
	} else {
	if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) {
	debug("getpeername failed: %.100s", strerror(errno));
	return -1;
	}
	}

	/* Work around Linux IPv6 weirdness */
	if (from.ss_family == AF_INET6)
	fromlen = sizeof(struct sockaddr_in6);

	/* Return port number. */
	if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
	strport, sizeof(strport), NI_NUMERICSERV)) != 0)
	fatal("get_sock_port: getnameinfo NI_NUMERICSERV failed: %s",
	r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
	return atoi(strport);
	}

	/* Returns remote/local port number for the current connection. */

	static int
	get_port(int local)
	{
	/*
	* If the connection is not a socket, return 65535. This is
	* intentionally chosen to be an unprivileged port number.
	*/
	if (!packet_connection_is_on_socket())
	return 65535;

	/* Get socket and return the port number. */
	return get_sock_port(packet_get_connection_in(), local);
	}

	int
	get_peer_port(int sock)
	{
	return get_sock_port(sock, 0);
	}

	int
	get_remote_port(void)
	{
	static int port = -1;

	/* Cache to avoid getpeername() on a dead connection */
	if (port == -1)
	port = get_port(0);

	return port;
	}

	int
	get_local_port(void)
	{
	return get_port(1);
	}