Bug 127284

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User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040116

Description of problem:
rwhod sends broadcasts to all interfaces on a machine.
In a Linux LVS (load balanced server cluster) I am running,
the rwhod broadcasts on the external interface were undesired.
They create unwanted ICMP error replies from some devices (DELL RAC
cards).

Only rwho broadcasts to the internal cluster network were desired.

If iptables filtering of rwhod broadcasts are used to filter outgoing
rwho broadcasts, then rwhod itself complains (every 3 minutes) to syslog:
rwhod[2215]: sendto(BROADCAST_ADDRESS): Operation not permitted

I added a patch to rwhod.c which gives it an additionla option:
rwhod -n eth1
prevents broadcasts to interface eth1.

My simple implmentation allows only one such option, no list of
interfaces.


Version-Release number of selected component (if applicable):
rwho-0.17-18

How reproducible:
Always

Steps to Reproduce:
1.it is not a bug, but a new feature
2.
3.
    

Actual Results:  feature works: rwhod -n eth1 
does not broadcast on eth1

Additional info:

here is the patch:
--- netkit-rwho-0.17/rwhod/rwhod.c
+++ netkit-rwho-0.17.modified/rwhod/rwhod.c
@@ -118,6 +118,7 @@
 static int use_broadcast = 0;
 static int need_init = 1;
 static int child_pid = 0;
+static char *ifname_nb = NULL; /* name of no-broadcast interface */

 #define WHDRSIZE       (((caddr_t) &((struct whod *) 0)->wd_we) \
                        - ((caddr_t) 0))
@@ -143,7 +144,7 @@
                exit(1);
        }

-       while ((opt = getopt(argc, argv, "bpau:")) != EOF) {
+       while ((opt = getopt(argc, argv, "bpaun:")) != EOF) {
            switch (opt) {
              case 'b':
                  use_broadcast = 1;
@@ -158,6 +159,9 @@
              case 'u':
                  user = optarg;
                  break;
+             case 'n':
+                 ifname_nb = optarg;
+                 break;
              case '?':
              default:
                  fprintf(stderr, "usage: rwhod [-bpa] [-u user]\n");
@@ -609,6 +613,9 @@
                if (np != NULL)
                        continue;
                ifreq = *ifr;
+                if (ifname_nb != NULL && strcmp(ifname_nb,
ifr->ifr_name) == 0){
+                  continue;
+               }
                np = (struct neighbor *)malloc(sizeof (*np));
                if (np == NULL)
                        continue;