chan_voter: Doesn't detect loss of master client when it is the only client

[ve7fet]

The "master" client is the master timing source for an instance. If it isn't available, then nothing else matters.

In a configuration where we have a master client and >1 "other" clients, and the master client disappears, we detect that and throw a warning: VOTER lost master timing source!!". We should probably do something else to shut the channel down, but that is a different issue.

In a configuration where we only have a master client configured, and that client goes away (ie network disconnected), chan_voter does not detect that anything is wrong. There are timeout checks, but it appears that we never get to that part of the code.

It appears that as long as there is data coming in the UDP port from multiple clients, we continue to iterate on the voter_reader loop, and can detect the loss of the master client.

However, if the master client is the only client sending data, and it stops, we aren't handling that case, since there are no more packets to process.

[ve7fet]

It looks like there is are a bunch of issues in the voter_reader thread about how we handle client connections, and what to do when they disappear.

Part of the problem appears to be this:

app_rpt/channels/chan_voter.c

Lines 4968 to 5010 in 1814fa7

	if (client->curmaster) {
	gettimeofday(&tv, NULL);
	for (client = clients; client; client = client->next) {
	if (!ast_tvzero(client->lastheardtime) &&
	(voter_tvdiff_ms(tv, client->lastheardtime) > ((client->ismaster) ? MASTER_TIMEOUT_MS : CLIENT_TIMEOUT_MS))) {
	ast_log(LOG_NOTICE, "VOTER client %s disconnect (timeout)\n", client->name);
	client->heardfrom = 0;
	client->respdigest = 0;
	}
	if (!client->heardfrom) {
	client->lastheardtime.tv_sec = client->lastheardtime.tv_usec = 0;
	}
	}
	if (check_client_sanity) {
	for (client = clients; client; client = client->next) {
	for (p = pvts; p; p = p->next) {
	if (p->nodenum == client->nodenum) {
	break;
	}
	}
	if (!p || p->priconn) {
	continue;
	}
	if (!client->respdigest) {
	continue;
	}
	for (client1 = client->next; client1; client1 = client1->next) {
	if (client1 == client) {
	continue;
	}
	if ((client1->sin.sin_addr.s_addr == client->sin.sin_addr.s_addr) &&
	(client1->sin.sin_port == client->sin.sin_port)) {
	if (!client1->respdigest) {
	continue;
	}
	client->respdigest = 0;
	client->heardfrom = 0;
	client1->respdigest = 0;
	client1->heardfrom = 0;
	}
	}
	}
	}

That block only runs when there is a master client connected... that's not right. We should be checking for ALL clients timing out and checking ALL clients sanity. Need to move that to a better place.