+/*************************************************
+* The udpsend ACL modifier *
+*************************************************/
+
+/* Called by acl_check_condition() below.
+
+Arguments:
+ arg the option string for udpsend=
+ log_msgptr for error messages
+
+Returns: OK - Completed.
+ DEFER - Problem with DNS lookup.
+ ERROR - Syntax error in options.
+*/
+
+static int
+acl_udpsend(uschar *arg, uschar **log_msgptr)
+{
+int sep = 0;
+uschar *hostname;
+uschar *portstr;
+uschar *portend;
+host_item *h;
+int portnum;
+int host_af;
+int len;
+int r, s;
+
+hostname = string_nextinlist(&arg, &sep, NULL, 0);
+portstr = string_nextinlist(&arg, &sep, NULL, 0);
+
+if (hostname == NULL)
+ {
+ *log_msgptr = "missing destination host in \"udpsend\" modifier";
+ return ERROR;
+ }
+if (portstr == NULL)
+ {
+ *log_msgptr = "missing destination port in \"udpsend\" modifier";
+ return ERROR;
+ }
+if (arg == NULL)
+ {
+ *log_msgptr = "missing datagram payload in \"udpsend\" modifier";
+ return ERROR;
+ }
+portnum = Ustrtol(portstr, &portend, 10);
+if (*portend != '\0')
+ {
+ *log_msgptr = "bad destination port in \"udpsend\" modifier";
+ return ERROR;
+ }
+
+/* Make a single-item host list. */
+h = store_get(sizeof(host_item));
+memset(h, 0, sizeof(host_item));
+h->name = hostname;
+h->port = portnum;
+h->mx = MX_NONE;
+
+if (string_is_ip_address(hostname, NULL))
+ h->address = hostname, r = HOST_FOUND;
+else
+ r = host_find_byname(h, NULL, 0, NULL, FALSE);
+if (r == HOST_FIND_FAILED || r == HOST_FIND_AGAIN)
+ {
+ *log_msgptr = "DNS lookup failed in \"udpsend\" modifier";
+ return DEFER;
+ }
+
+HDEBUG(D_acl)
+ debug_printf("udpsend [%s]:%d %s\n", h->address, portnum, arg);
+
+host_af = (Ustrchr(h->address, ':') == NULL)? AF_INET:AF_INET6;
+r = s = ip_socket(SOCK_DGRAM, host_af);
+if (r < 0) goto defer;
+r = ip_connect(s, host_af, h->address, portnum, 1);
+if (r < 0) goto defer;
+len = strlen(arg);
+r = send(s, arg, len, MSG_NOSIGNAL);
+if (r < 0) goto defer;
+if (r < len)
+ {
+ *log_msgptr =
+ string_sprintf("\"udpsend\" truncated from %d to %d octets", len, r);
+ return DEFER;
+ }
+
+HDEBUG(D_acl)
+ debug_printf("udpsend %d bytes\n", r);
+
+return OK;
+
+defer:
+*log_msgptr = string_sprintf("\"udpsend\" failed: %s", strerror(errno));
+return DEFER;
+}
+
+
+