static int nl_async(struct nlmsghdr *h)
{
if (h->nlmsg_type == NLMSG_ERROR)
{
struct nlmsgerr *err = NLMSG_DATA(h);
if (err->error != 0)
my_syslog(LOG_ERR, _("netlink returns error: %s"), strerror(-(err->error)));
return 0;
}
else if (h->nlmsg_pid == 0 && h->nlmsg_type == RTM_NEWROUTE)
{
/* We arrange to receive netlink multicast messages whenever the network route is added.
If this happens and we still have a DNS packet in the buffer, we re-send it.
This helps on DoD links, where frequently the packet which triggers dialling is
a DNS query, which then gets lost. By re-sending, we can avoid the lookup
failing. */
struct rtmsg *rtm = NLMSG_DATA(h);
if (rtm->rtm_type == RTN_UNICAST && rtm->rtm_scope == RT_SCOPE_LINK)
{
/* Force re-reading resolv file right now, for luck. */
daemon->last_resolv = 0;
if (daemon->srv_save)
{
int fd;
if (daemon->srv_save->sfd)
fd = daemon->srv_save->sfd->fd;
else if (daemon->rfd_save && daemon->rfd_save->refcount != 0)
fd = daemon->rfd_save->fd;
else
return 0;
while(sendto(fd, daemon->packet, daemon->packet_len, 0,
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
}
}
return 0;
}
else if (h->nlmsg_type == RTM_NEWADDR)
{
#ifdef HAVE_DHCP6
/* force RAs to sync new network and pick up new interfaces. */
if (daemon->ra_contexts)
{
schedule_subnet_map();
ra_start_unsolicted(dnsmasq_time(), NULL);
/* cause lease_update_file to run after we return, in case we were called from
iface_enumerate and can't re-enter it now */
send_alarm(0, 0);
}
#endif
return 1; /* clever bind mode - rescan */
}
return 0;
}
/* We arrange to receive netlink multicast messages whenever the network route is added.
If this happens and we still have a DNS packet in the buffer, we re-send it.
This helps on DoD links, where frequently the packet which triggers dialling is
a DNS query, which then gets lost. By re-sending, we can avoid the lookup
failing. Note that we only accept these messages from the kernel (pid == 0) */
static void nl_routechange(struct nlmsghdr *h)
{
if (h->nlmsg_pid == 0 && h->nlmsg_type == RTM_NEWROUTE)
{
struct rtmsg *rtm = NLMSG_DATA(h);
int fd;
if (rtm->rtm_type != RTN_UNICAST || rtm->rtm_scope != RT_SCOPE_LINK)
return;
/* Force re-reading resolv file right now, for luck. */
daemon->last_resolv = 0;
#ifdef HAVE_DHCP6
/* force RAs to sync new network and pick up new interfaces. */
if (daemon->ra_contexts)
{
schedule_subnet_map();
ra_start_unsolicted(dnsmasq_time(), NULL);
/* cause lease_update_file to run after we return, in case we were called from
iface_enumerate and can't re-enter it now */
send_alarm(0, 0);
}
#endif
if (daemon->srv_save)
{
if (daemon->srv_save->sfd)
fd = daemon->srv_save->sfd->fd;
else if (daemon->rfd_save && daemon->rfd_save->refcount != 0)
fd = daemon->rfd_save->fd;
else
return;
while(sendto(fd, daemon->packet, daemon->packet_len, 0,
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
}
}
}
