Netlink: Handle interfaces with missing broadcast addresses

diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c
index 25c078c17cc7e75e985d7b6435d01d3451a2b5cf..856869ac24f1acea6783b20e268b507d58c20230 100644 (file)
--- a/sysdep/linux/netlink.c
+++ b/sysdep/linux/netlink.c
@@ -953,18 +953,15 @@ nl_parse_addr4(struct ifaddrmsg *i, int scan, int new)
       if (i->ifa_prefixlen == IP4_MAX_PREFIX_LENGTH - 2)
        ifa.opposite = ipa_opposite_m2(ifa.ip);
 
-      if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST])
-       {
-         ip4_addr xbrd = rta_get_ip4(a[IFA_BROADCAST]);
-         ip4_addr ybrd = ip4_or(ipa_to_ip4(ifa.ip), ip4_not(ip4_mkmask(i->ifa_prefixlen)));
-
-         if (ip4_equal(xbrd, net4_prefix(&ifa.prefix)) || ip4_equal(xbrd, ybrd))
-           ifa.brd = ipa_from_ip4(xbrd);
-         else if (ifi->flags & IF_TMP_DOWN) /* Complain only during the first scan */
-           {
-             log(L_ERR "KIF: Invalid broadcast address %I4 for %s", xbrd, ifi->name);
-             ifa.brd = ipa_from_ip4(ybrd);
-           }
+      if (ifi->flags & IF_BROADCAST)
+        {
+         /* If kernel offers us a broadcast address, we trust it */
+         if (a[IFA_BROADCAST])
+           ifa.brd = ipa_from_ip4(rta_get_ip4(a[IFA_BROADCAST]));
+         /* Otherwise we create one (except for /31) */
+         else if (i->ifa_prefixlen < (IP4_MAX_PREFIX_LENGTH - 1))
+           ifa.brd = ipa_from_ip4(ip4_or(ipa_to_ip4(ifa.ip),
+                                         ip4_not(ip4_mkmask(i->ifa_prefixlen))));
        }
     }