Pi-Hole/dnsmasq
1
0
Fork 0
mirror of https://github.com/pi-hole/dnsmasq.git synced 2025-12-19 18:28:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

Revise resource handling for number of concurrent DNS queries.

Browse Source 
This used to have a global limit, but that has a problem when using
different servers for different upstream domains. Queries which are
routed by domain to an upstream server which is not responding will
build up and trigger the limit, which breaks DNS service for all other
domains which could be handled by other servers. The change is to make
the limit per server-group, where a server group is the set of servers
configured for a particular domain. In the common case, where only
default servers are declared, there is no effective change.
This commit is contained in:
Simon Kelley
2021-06-13 21:29:22 +01:00
parent 4a6550d69a
commit 3236f358f8
7 changed files with 87 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
src/dnsmasq.c
View File

@@ -24,7 +24,7 @@ struct daemon *daemon;
static volatile pid_t pid = 0;
static volatile int pipewrite;
static int set_dns_listeners(time_t now);
static void set_dns_listeners(void);
static void check_dns_listeners(time_t now);
static void sig_handler(int sig);
static void async_event(int pipe, time_t now);
@@ -1042,16 +1042,10 @@ int main (int argc, char **argv)
while (1)
{
int t, timeout = -1;
int timeout = -1;
poll_reset();
/* if we are out of resources, find how long we have to wait
for some to come free, we'll loop around then and restart
listening for queries */
if ((t = set_dns_listeners(now)) != 0)
timeout = t * 1000;
/* Whilst polling for the dbus, or doing a tftp transfer, wake every quarter second */
if (daemon->tftp_trans ||
(option_bool(OPT_DBUS) && !daemon->dbus))
@@ -1061,6 +1055,8 @@ int main (int argc, char **argv)
else if (is_dad_listeners())
timeout = 1000;
set_dns_listeners();
#ifdef HAVE_DBUS
set_dbus_listeners();
#endif
@@ -1685,12 +1681,12 @@ void clear_cache_and_reload(time_t now)
#endif
}
static int set_dns_listeners(time_t now)
static void set_dns_listeners(void)
{
struct serverfd *serverfdp;
struct listener *listener;
struct randfd_list *rfl;
int wait = 0, i;
int i;
#ifdef HAVE_TFTP
int tftp = 0;
@@ -1703,10 +1699,6 @@ static int set_dns_listeners(time_t now)
}
#endif
/* will we be able to get memory? */
if (daemon->port != 0)
get_new_frec(now, &wait, NULL);
for (serverfdp = daemon->sfds; serverfdp; serverfdp = serverfdp->next)
poll_listen(serverfdp->fd, POLLIN);
@@ -1725,10 +1717,9 @@ static int set_dns_listeners(time_t now)
for (listener = daemon->listeners; listener; listener = listener->next)
{
/* only listen for queries if we have resources */
if (listener->fd != -1 && wait == 0)
if (listener->fd != -1)
poll_listen(listener->fd, POLLIN);
/* Only listen for TCP connections when a process slot
is available. Death of a child goes through the select loop, so
we don't need to explicitly arrange to wake up here,
@@ -1741,15 +1732,12 @@ static int set_dns_listeners(time_t now)
if (tftp <= daemon->tftp_max && listener->tftpfd != -1)
poll_listen(listener->tftpfd, POLLIN);
#endif
}
if (!option_bool(OPT_DEBUG))
for (i = 0; i < MAX_PROCS; i++)
if (daemon->tcp_pipes[i] != -1)
poll_listen(daemon->tcp_pipes[i], POLLIN);
return wait;
}
static void check_dns_listeners(time_t now)
@@ -2100,7 +2088,7 @@ int delay_dhcp(time_t start, int sec, int fd, uint32_t addr, unsigned short id)
poll_reset();
if (fd != -1)
poll_listen(fd, POLLIN);
set_dns_listeners(now);
set_dns_listeners();
set_log_writer();
#ifdef HAVE_DHCP6