From b0019c78b011504b32f054eac95bf3b27b8e8367 Mon Sep 17 00:00:00 2001
From: Tony Finch <dot@dotat.at>
Date: Fri, 12 Oct 2012 14:54:07 +0100
Subject: [PATCH] The udpsend ACL modifier.

This is for reporting mailer activity without going via the log files.
---
 src/src/acl.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)

diff --git a/src/src/acl.c b/src/src/acl.c
index 4f64e0a53..11626709d 100644
--- a/src/src/acl.c
+++ b/src/src/acl.c
@@ -107,6 +107,7 @@ enum { ACLC_ACL,
        ACLC_SPF,
        ACLC_SPF_GUESS,
 #endif
+       ACLC_UDPSEND,
        ACLC_VERIFY };
 
 /* ACL conditions/modifiers: "delay", "control", "continue", "endpass",
@@ -171,6 +172,7 @@ static uschar *conditions[] = {
   US"spf",
   US"spf_guess",
 #endif
+  US"udpsend",
   US"verify" };
 
 
@@ -315,6 +317,7 @@ static uschar cond_expand_at_top[] = {
   TRUE,    /* spf */
   TRUE,    /* spf_guess */
 #endif
+  TRUE,    /* udpsend */
   TRUE     /* verify */
 };
 
@@ -379,6 +382,7 @@ static uschar cond_modifiers[] = {
   FALSE,   /* spf */
   FALSE,   /* spf_guess */
 #endif
+  TRUE,    /* udpsend */
   FALSE    /* verify */
 };
 
@@ -579,6 +583,8 @@ static unsigned int cond_forbids[] = {
     (1<<ACL_WHERE_NOTSMTP_START),
   #endif
 
+  0,                                               /* udpsend */
+
   /* Certain types of verify are always allowed, so we let it through
   always and check in the verify function itself */
 
@@ -2816,6 +2822,106 @@ return rc;
 
 
 
+/*************************************************
+*            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;
+}
+
+
+
 /*************************************************
 *   Handle conditions/modifiers on an ACL item   *
 *************************************************/
@@ -3546,6 +3652,10 @@ for (; cb != NULL; cb = cb->next)
     break;
     #endif
 
+    case ACLC_UDPSEND:
+    rc = acl_udpsend(arg, log_msgptr);
+    break;
+
     /* If the verb is WARN, discard any user message from verification, because
     such messages are SMTP responses, not header additions. The latter come
     only from explicit "message" modifiers. However, put the user message into
-- 
2.25.1