+ if (!lookup_name(&ss, ss_len, name_buf, sizeof name_buf, port_buf, sizeof port_buf))
+ check_name(&ss, ss_len, name_buf, port_buf);
+
+ return name_buf;
+}
+
+
+/**
+ * Look up a name from @p ss into @p name_buf.
+ **/
+static int lookup_name(const struct sockaddr_storage *ss,
+ socklen_t ss_len,
+ char *name_buf, size_t name_buf_len,
+ char *port_buf, size_t port_buf_len)
+{
+ int name_err;
+
+#ifdef INET6
+ if (get_sockaddr_family(ss) == AF_INET6 &&
+ IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
+ /* OK, so ss is in the IPv6 family, but it is really
+ * an IPv4 address: something like
+ * "::ffff:10.130.1.2". If we use it as-is, then the
+ * reverse lookup might fail or perhaps something else
+ * bad might happen. So instead we convert it to an
+ * equivalent address in the IPv4 address family. */
+ struct sockaddr_in6 sin6;
+ struct sockaddr_in *sin;
+
+ memcpy(&sin6, ss, sizeof(sin6));
+ sin = (struct sockaddr_in *)ss;
+ memset(sin, 0, sizeof(*sin));
+ sin->sin_family = AF_INET;
+ ss_len = sizeof(struct sockaddr_in);
+#ifdef HAVE_SOCKADDR_LEN
+ sin->sin_len = ss_len;
+#endif
+ sin->sin_port = sin6.sin6_port;
+ /* FIXME: Isn't there a macro we can use here rather
+ * than grovelling through the struct? It might be
+ * wrong on some systems. */
+ memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
+ sizeof(sin->sin_addr));
+ }
+#endif
+
+ /* reverse lookup */
+ name_err = getnameinfo((struct sockaddr *) ss, ss_len,
+ name_buf, name_buf_len,
+ port_buf, port_buf_len,
+ NI_NAMEREQD | NI_NUMERICSERV);
+ if (name_err != 0) {
+ strcpy(name_buf, default_name);
+ rprintf(FERROR, RSYNC_NAME ": name lookup failed: %s\n",
+ gai_strerror(name_err));
+ return name_err;
+ }
+
+ return 0;
+}
+
+
+
+/* Do a forward lookup on name_buf and make sure it corresponds to ss
+ * -- otherwise we may be being spoofed. If we suspect we are, then
+ * we don't abort the connection but just emit a warning. */
+static int check_name(const struct sockaddr_storage *ss,
+ socklen_t ss_len,
+ char *name_buf,
+ const char *port_buf)
+{
+ struct addrinfo hints, *res, *res0;
+ int error;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = PF_UNSPEC;
+ hints.ai_flags = AI_CANONNAME;
+ hints.ai_socktype = SOCK_STREAM;
+ error = getaddrinfo(name_buf, port_buf, &hints, &res0);
+ if (error) {
+ strcpy(name_buf, default_name);
+ rprintf(FERROR,
+ RSYNC_NAME ": forward name lookup for %s:%s failed: %s\n",
+ name_buf, port_buf,
+ gai_strerror(error));
+ return error;