Bug in ctdb_sys_have_ip (CTDB) ?

[miguel.sanders at arcelormittal.com]

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;
		break;
	case AF_INET6:
		addr->ip6.sin6_port = 0;
		break;
	}

	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));

	close(s);
	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?

Thanks!

Met vriendelijke groet
Best regards
Bien à vous

Miguel SANDERS
ArcelorMittal Gent

UNIX Systems & Storage
IT Supply Western Europe | John Kennedylaan 51
B-9042 Gent

T +32 9 347 3538 | F +32 9 347 4901 | M +32478 805 023
E miguel.sanders at arcelormittal.com
www.arcelormittal.com/gent


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