/*
find the interface to use for sending a outgoing request
*/
struct nbtd_interface *nbtd_find_request_iface(struct nbtd_server *nbtd_server,
const char *address, bool allow_bcast_iface)
{
struct nbtd_interface *cur;
/* try to find a exact match */
for (cur=nbtd_server->interfaces;cur;cur=cur->next) {
if (iface_same_net(address, cur->ip_address, cur->netmask)) {
DEBUG(10,("find interface for dst[%s] ip: %s/%s (iface[%p])\n",
address, cur->ip_address, cur->netmask, cur));
return cur;
}
}
/* no exact match, if we have the broadcast interface, use that */
if (allow_bcast_iface && nbtd_server->bcast_interface) {
cur = nbtd_server->bcast_interface;
DEBUG(10,("find interface for dst[%s] ip: %s/%s (bcast iface[%p])\n",
address, cur->ip_address, cur->netmask, cur));
return cur;
}
/* fallback to first interface */
cur = nbtd_server->interfaces;
DEBUG(10,("find interface for dst[%s] ip: %s/%s (default iface[%p])\n",
address, cur->ip_address, cur->netmask, cur));
return cur;
}
static void nbtd_wins_randomize1Clist(struct loadparm_context *lp_ctx,
const char **addresses, struct socket_address *src)
{
const char *mask;
const char *tmp;
uint32_t num_addrs;
uint32_t idx, sidx;
int r;
for (num_addrs=0; addresses[num_addrs]; num_addrs++) { /* noop */ }
if (num_addrs <= 1) return; /* nothing to do */
/* first sort the addresses depending on the matching to the client */
ldb_qsort(addresses, num_addrs , sizeof(addresses[0]),
src, (ldb_qsort_cmp_fn_t)nbtd_wins_randomize1Clist_sort);
mask = lp_parm_string(lp_ctx, NULL, "nbtd", "wins_randomize1Clist_mask");
if (!mask) {
mask = "255.255.255.0";
}
/*
* choose a random address to be the first in the response to the client,
* preferr the addresses inside the nbtd:wins_randomize1Clist_mask netmask
*/
r = random();
idx = sidx = r % num_addrs;
while (1) {
bool same;
/* if the current one is in the same subnet, use it */
same = iface_same_net(addresses[idx], src->addr, mask);
if (same) {
sidx = idx;
break;
}
/* we need to check for idx == 0, after checking for the same net */
if (idx == 0) break;
/*
* if we haven't found an address in the same subnet, search in ones
* which match the client more
*
* some notes:
*
* it's not "idx = idx % r" but "idx = r % idx"
* because in "a % b" b is the allowed range
* and b-1 is the maximum possible result, so it must be decreasing
* and the above idx == 0 check breaks the while(1) loop.
*/
idx = r % idx;
}
/* note sidx == 0 is also valid here ... */
tmp = addresses[0];
addresses[0] = addresses[sidx];
addresses[sidx] = tmp;
}