[PATCH] Increase the size of the netlink recvmsg buffer

On systems with a large number of network interfaces keepalived may 
report:
"Netlink: error: message truncated messages"
<and>
"VRRP is trying to assign VIP to unknown qr-dc4f0313-ca interface !!! go 
out
  and fix your conf !!!"

This was reported on a system running OpenStack/Nutron.

I found that the netlink recvmsg buffer was too small causing messages 
to be
truncated. Increasing the buffer from 4K to 8K prevents the problem.
(linux/netlink.h suggests using an 8K buffer).

I tested the fix by creating 100 veth interfaces and verifying the 
errors
did not return.

Signed-off-by: David Wilder <[email protected]>

---
  keepalived/vrrp/vrrp_netlink.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/keepalived/vrrp/vrrp_netlink.c 
b/keepalived/vrrp/vrrp_netlink.c
index d7adffa..7897b4c 100644
--- a/keepalived/vrrp/vrrp_netlink.c
+++ b/keepalived/vrrp/vrrp_netlink.c
@@ -273,7 +273,7 @@ netlink_parse_info(int (*filter) (struct sockaddr_nl 
*, struct nlmsghdr *),
  	int error;

  	while (1) {
-		char buf[4096];
+		char buf[8192];
  		struct iovec iov = { buf, sizeof buf };
  		struct sockaddr_nl snl;
  		struct msghdr msg =
-- 
1.8.3.1


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