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1/* $OpenBSD: canohost.c,v 1.78 2026/02/14 00:18:34 jsg Exp $ */
2/*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * Functions for returning the canonical host name of the remote site.
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 */
14
15#include <sys/types.h>
16#include <sys/socket.h>
17#include <sys/un.h>
18
19#include <netinet/in.h>
20
21#include <errno.h>
22#include <netdb.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26#include <stdarg.h>
27#include <unistd.h>
28
29#include "xmalloc.h"
30#include "log.h"
31#include "canohost.h"
32#include "misc.h"
33
34/*
35 * Returns the local/remote IP-address/hostname of socket as a string.
36 * The returned string must be freed.
37 */
38static char *
39get_socket_address(int sock, int remote, int flags)
40{
41 struct sockaddr_storage addr;
42 socklen_t addrlen;
43 char ntop[NI_MAXHOST];
44 int r;
45
46 if (sock < 0)
47 return NULL;
48
49 /* Get IP address of client. */
50 addrlen = sizeof(addr);
51 memset(&addr, 0, sizeof(addr));
52
53 if (remote) {
54 if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) != 0)
55 return NULL;
56 } else {
57 if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) != 0)
58 return NULL;
59 }
60
61 switch (addr.ss_family) {
62 case AF_INET:
63 case AF_INET6:
64 /* Get the address in ascii. */
65 if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,
66 sizeof(ntop), NULL, 0, flags)) != 0) {
67 error_f("getnameinfo %d failed: %s",
68 flags, ssh_gai_strerror(r));
69 return NULL;
70 }
71 return xstrdup(ntop);
72 case AF_UNIX:
73 /* Get the Unix domain socket path. */
74 return xstrdup(((struct sockaddr_un *)&addr)->sun_path);
75 default:
76 /* We can't look up remote Unix domain sockets. */
77 return NULL;
78 }
79}
80
81char *
82get_peer_ipaddr(int sock)
83{
84 char *p;
85
86 if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)
87 return p;
88 return xstrdup("UNKNOWN");
89}
90
91char *
92get_local_ipaddr(int sock)
93{
94 char *p;
95
96 if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)
97 return p;
98 return xstrdup("UNKNOWN");
99}
100
101char *
102get_local_name(int fd)
103{
104 char *host, myname[NI_MAXHOST];
105
106 /* Assume we were passed a socket */
107 if ((host = get_socket_address(fd, 0, NI_NAMEREQD)) != NULL)
108 return host;
109
110 /* Handle the case where we were passed a pipe */
111 if (gethostname(myname, sizeof(myname)) == -1) {
112 verbose_f("gethostname: %s", strerror(errno));
113 host = xstrdup("UNKNOWN");
114 } else {
115 host = xstrdup(myname);
116 }
117
118 return host;
119}
120
121/* Returns the local/remote port for the socket. */
122
123static int
124get_sock_port(int sock, int local)
125{
126 struct sockaddr_storage from;
127 socklen_t fromlen;
128 char strport[NI_MAXSERV];
129 int r;
130
131 if (sock < 0)
132 return -1;
133 /* Get IP address of client. */
134 fromlen = sizeof(from);
135 memset(&from, 0, sizeof(from));
136 if (local) {
137 if (getsockname(sock, (struct sockaddr *)&from, &fromlen) == -1) {
138 error("getsockname failed: %.100s", strerror(errno));
139 return 0;
140 }
141 } else {
142 if (getpeername(sock, (struct sockaddr *)&from, &fromlen) == -1) {
143 debug("getpeername failed: %.100s", strerror(errno));
144 return -1;
145 }
146 }
147
148 /* Non-inet sockets don't have a port number. */
149 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
150 return 0;
151
152 /* Return port number. */
153 if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
154 strport, sizeof(strport), NI_NUMERICSERV)) != 0)
155 fatal_f("getnameinfo NI_NUMERICSERV failed: %s",
156 ssh_gai_strerror(r));
157 return atoi(strport);
158}
159
160int
161get_peer_port(int sock)
162{
163 return get_sock_port(sock, 0);
164}
165
166int
167get_local_port(int sock)
168{
169 return get_sock_port(sock, 1);
170}