+int
+ip_tcpsocket(const uschar * hostport, uschar ** errstr, int tmo)
+{
+int scan;
+uschar hostname[256];
+unsigned int portlow, porthigh;
+
+/* extract host and port part */
+scan = sscanf(CS hostport, "%255s %u-%u", hostname, &portlow, &porthigh);
+if (scan != 3)
+ {
+ if (scan != 2)
+ {
+ *errstr = string_sprintf("invalid socket '%s'", hostport);
+ return -1;
+ }
+ porthigh = portlow;
+ }
+
+return ip_connectedsocket(SOCK_STREAM, hostname, portlow, porthigh,
+ tmo, NULL, errstr);
+}
+
+int
+ip_unixsocket(const uschar * path, uschar ** errstr)
+{
+int sock;
+struct sockaddr_un server;
+
+if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+ {
+ *errstr = US"can't open UNIX socket.";
+ return -1;
+ }
+
+callout_address = string_copy(path);
+server.sun_family = AF_UNIX;
+Ustrncpy(server.sun_path, path, sizeof(server.sun_path)-1);
+server.sun_path[sizeof(server.sun_path)-1] = '\0';
+if (connect(sock, (struct sockaddr *) &server, sizeof(server)) < 0)
+ {
+ int err = errno;
+ (void)close(sock);
+ *errstr = string_sprintf("unable to connect to UNIX socket (%s): %s",
+ path, strerror(err));
+ return -1;
+ }
+return sock;
+}
+
+int
+ip_streamsocket(const uschar * spec, uschar ** errstr, int tmo)
+{
+return *spec == '/'
+ ? ip_unixsocket(spec, errstr) : ip_tcpsocket(spec, errstr, tmo);
+}
+