Bug in ctdb_sys_have_ip (CTDB) ?

miguel.sanders at arcelormittal.com miguel.sanders at arcelormittal.com
Tue Jun 2 17:08:44 GMT 2009

Hi guys

I have been searching for a problem in CTDB (not on Linux, on AIX) all day and I finally was able to determine the root cause.
In system_common.c, there is a "ctdb_sys_have_ip" function which should return true if a local interface has a specific IP alias.
The function looks like this:
  see if we currently have an interface with the given IP

  we try to bind to it, and if that fails then we don't have that IP
  on an interface
bool ctdb_sys_have_ip(ctdb_sock_addr *_addr)
	int s;
	int ret;
	ctdb_sock_addr __addr = *_addr;
	ctdb_sock_addr *addr = &__addr;

	switch (addr->sa.sa_family) {
	case AF_INET:
		addr->ip.sin_port = 0;
	case AF_INET6:
		addr->ip6.sin6_port = 0;

	s = socket(addr->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
	if (s == -1) {
		return false;

	ret = bind(s, (struct sockaddr *)addr, sizeof(ctdb_sock_addr));

	return ret == 0;

I just don't see how this piece of code guarantees that the IP address to test (*_addr) is attached to a local interface.
Afaik this will always return true if the IP address is somewhere on the subnet.

Am I missing something?


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E miguel.sanders at arcelormittal.com

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