1 /* -*- c-file-style: "linux" -*-
3 rsync -- fast file replication program
5 Copyright (C) 1992-2001 by Andrew Tridgell <tridge@samba.org>
6 Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 * Functions for looking up the remote name or addr of a socket.
28 * This file is now converted to use the new-style getaddrinfo()
29 * interface, which supports IPv6 but is also supported on recent
30 * IPv4-only machines. On systems that don't have that interface, we
31 * emulate it using the KAME implementation.
36 static const char default_name[] = "UNKNOWN";
40 * Return the IP addr of the client as a string
42 char *client_addr(int fd)
44 struct sockaddr_storage ss;
45 socklen_t length = sizeof ss;
46 static char addr_buf[100];
47 static int initialised;
49 if (initialised) return addr_buf;
53 client_sockaddr(fd, &ss, &length);
55 getnameinfo((struct sockaddr *)&ss, length,
56 addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
62 static int get_sockaddr_family(const struct sockaddr_storage *ss)
64 return ((struct sockaddr *) ss)->sa_family;
69 * Return the DNS name of the client.
71 * The name is statically cached so that repeated lookups are quick,
72 * so there is a limit of one lookup per customer.
74 * If anything goes wrong, including the name->addr->name check, then
75 * we just use "UNKNOWN", so you can use that value in hosts allow
78 char *client_name(int fd)
80 struct sockaddr_storage ss;
81 socklen_t ss_len = sizeof ss;
82 static char name_buf[100];
83 static char port_buf[100];
84 static int initialised;
86 if (initialised) return name_buf;
88 strcpy(name_buf, default_name);
91 client_sockaddr(fd, &ss, &ss_len);
93 if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, port_buf, sizeof port_buf))
94 check_name(fd, &ss, name_buf, port_buf);
102 * Get the sockaddr for the client.
104 * If it comes in as an ipv4 address mapped into IPv6 format then we
105 * convert it back to a regular IPv4.
107 void client_sockaddr(int fd,
108 struct sockaddr_storage *ss,
111 if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
112 /* FIXME: Can we really not continue? */
113 rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n",
114 fd, strerror(errno));
115 exit_cleanup(RERR_SOCKETIO);
119 if (get_sockaddr_family(ss) == AF_INET6 &&
120 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
121 /* OK, so ss is in the IPv6 family, but it is really
122 * an IPv4 address: something like
123 * "::ffff:10.130.1.2". If we use it as-is, then the
124 * reverse lookup might fail or perhaps something else
125 * bad might happen. So instead we convert it to an
126 * equivalent address in the IPv4 address family. */
127 struct sockaddr_in6 sin6;
128 struct sockaddr_in *sin;
130 memcpy(&sin6, ss, sizeof(sin6));
131 sin = (struct sockaddr_in *)ss;
132 memset(sin, 0, sizeof(*sin));
133 sin->sin_family = AF_INET;
134 *ss_len = sizeof(struct sockaddr_in);
135 #ifdef HAVE_SOCKADDR_LEN
136 sin->sin_len = *ss_len;
138 sin->sin_port = sin6.sin6_port;
140 /* There is a macro to extract the mapped part
141 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
142 * to be present in the Linux headers. */
143 memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
144 sizeof(sin->sin_addr));
151 * Look up a name from @p ss into @p name_buf.
153 int lookup_name(int fd, const struct sockaddr_storage *ss,
155 char *name_buf, size_t name_buf_len,
156 char *port_buf, size_t port_buf_len)
161 name_err = getnameinfo((struct sockaddr *) ss, ss_len,
162 name_buf, name_buf_len,
163 port_buf, port_buf_len,
164 NI_NAMEREQD | NI_NUMERICSERV);
166 strcpy(name_buf, default_name);
167 rprintf(FERROR, RSYNC_NAME ": name lookup failed for %s: %s\n",
169 gai_strerror(name_err));
179 * Compare an addrinfo from the resolver to a sockinfo.
181 * Like strcmp, returns 0 for identical.
183 int compare_addrinfo_sockaddr(const struct addrinfo *ai,
184 const struct sockaddr_storage *ss)
186 int ss_family = get_sockaddr_family(ss);
187 const char fn[] = "compare_addrinfo_sockaddr";
189 if (ai->ai_family != ss_family) {
191 "%s: response family %d != %d\n",
192 fn, ai->ai_family, ss_family);
196 /* The comparison method depends on the particular AF. */
197 if (ss_family == AF_INET) {
198 const struct sockaddr_in *sin1, *sin2;
200 sin1 = (const struct sockaddr_in *) ss;
201 sin2 = (const struct sockaddr_in *) ai->ai_addr;
203 return memcmp(&sin1->sin_addr, &sin2->sin_addr,
204 sizeof sin1->sin_addr);
207 else if (ss_family == AF_INET6) {
208 const struct sockaddr_in6 *sin1, *sin2;
210 sin1 = (const struct sockaddr_in6 *) ss;
211 sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
213 return memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
214 sizeof sin1->sin6_addr);
225 * Do a forward lookup on @p name_buf and make sure it corresponds to
226 * @p ss -- otherwise we may be being spoofed. If we suspect we are,
227 * then we don't abort the connection but just emit a warning, and
228 * change @p name_buf to be "UNKNOWN".
230 int check_name(int fd,
231 const struct sockaddr_storage *ss,
233 const char *port_buf)
235 struct addrinfo hints, *res, *res0;
237 int ss_family = get_sockaddr_family(ss);
239 memset(&hints, 0, sizeof(hints));
240 hints.ai_family = ss_family;
241 hints.ai_flags = AI_CANONNAME;
242 hints.ai_socktype = SOCK_STREAM;
243 error = getaddrinfo(name_buf, port_buf, &hints, &res0);
246 RSYNC_NAME ": forward name lookup for %s failed: %s\n",
247 name_buf, gai_strerror(error));
248 strcpy(name_buf, default_name);
253 /* Given all these results, we expect that one of them will be
254 * the same as ss. The comparison is a bit complicated. */
255 for (res = res0; res; res = res->ai_next) {
256 if (!compare_addrinfo_sockaddr(res, ss))
257 break; /* OK, identical */
261 /* We hit the end of the list without finding an
262 * address that was the same as ss. */
263 rprintf(FERROR, RSYNC_NAME
264 ": no known address for \"%s\": "
265 "spoofed address?\n",
267 strcpy(name_buf, default_name);
268 } else if (res == NULL) {
269 /* We hit the end of the list without finding an
270 * address that was the same as ss. */
271 rprintf(FERROR, RSYNC_NAME
272 ": %s is not a known address for \"%s\": "
273 "spoofed address?\n",
276 strcpy(name_buf, default_name);