syslogd option to listen on a single address

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Hi,

Here is code for an additional syslogd option which I have found useful. It
allows syslogd to listen on only 1 address if desired. In our setup it only
listens on our private net. The changes were made on the syslogd.c in the
redhat 7.3 sysklogd-1.4.1-8.src.rpm package.

Here are the diffs on syslogd.c:

--- syslogd.c.orig Thu Aug 16 03:16:05 2001
+++ syslogd.c Sun Aug 4 21:32:45 2002
@@ -727,4 +727,6 @@
  int finet = -1; /* Internet datagram socket */
  int LogPort; /* port number for INET connections */
+struct in_addr ListenAddr; /* ip address to listen on - Doug */
+int wildcard = 1; /* bool for wildcard address - or not - Doug */
  int Initialized = 0; /* set when we have initialized ourselves */
  int MarkInterval = 20 * 60; /* interval between marks in seconds */
@@ -831,5 +833,5 @@
          }
 
- while ((ch = getopt(argc, argv, "a:dhf:l:m:np:rs:vx")) != EOF)
+ while ((ch = getopt(argc, argv, "a:dhf:i:l:m:np:rs:vx")) != EOF)
                  switch((char)ch) {
                  case 'a':
@@ -848,4 +850,11 @@
                          NoHops = 0;
                          break;
+ case 'i': /* Doug */
+ if ( ! inet_aton(optarg, &ListenAddr) )
+ fprintf (stderr, "Invalid IP for listen address," \
+ "using wildcard address.\n");
+ else
+ wildcard = 0;
+ break;
                  case 'l':
                          if (LocalHosts) {
@@ -1231,4 +1240,11 @@
          sin.sin_family = AF_INET;
          sin.sin_port = LogPort;
+
+ /* Doug */
+ if ( ! wildcard )
+ sin.sin_addr.s_addr = ListenAddr.s_addr;
+ else
+ sin.sin_addr.s_addr = htonl(INADDR_ANY);
+
          if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, \
                         (char *) &on, sizeof(on)) < 0 ) {

As you can see it adds an -i ip address option (only makes sense with the -r
option) which alows you to choose 1 address to listen on.

If the ip address given is malformed, inet_aton fails and syslogd
will default to listening on all interfaces. If a non-local ip is
given bind will fail and
syslogd will not listen on any address.

Apologies for the /* Doug */ comments - these were to mark where I
had been poking around.

Here is the patch to the man page:

--- sysklogd.8.orig Sun Aug 4 21:42:29 2002
+++ sysklogd.8 Sun Aug 4 21:43:56 2002
@@ -16,4 +16,7 @@
  ]
  .RB [ " \-h " ]
+.RB [ " \-i "
+.I ip address
+]
  .RB [ " \-l "
  .I hostlist
@@ -105,4 +108,9 @@
  forward any remote messages it receives to forwarding hosts which have been
  defined.
+.TP
+.BI "\-i " "ip address"
+Specify an ip address to listen on. Otherwise syslogd will use the
+wildcard address.
+.TP
  .BI "\-l " "hostlist"
  Specify a hostname that should be logged only with its simple hostname

Doug
|-----------------------------------------------|
| Dr Doug Chappell |
| Computer Support |
| School of Molecular and Microbial Biosciences |
| The University of Sydney, 2006 NSW AUSTRALIA |
| d.chappell@mmb.usyd.edu.au |
|-----------------------------------------------|
| Phone: 61 2 9351 2511 | Fax: 61 2 9351 4726 |
|-----------------------------------------------|

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