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

Further optimisation of --port-limit.

Browse Source 
No longer try and fail to open every port when the port range
is in complete use; go straight to re-using an existing socket.

Die at startup if port range is smaller than --port-limit, since
the code behaves badly in this case.
This commit is contained in:
Simon Kelley
2022-09-09 18:18:46 +01:00
parent 3f56bb8ba1
commit c0e731d545
4 changed files with 64 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

70
src/forward.c
View File

@@ -2435,6 +2435,21 @@ static int random_sock(struct server *s)
if ((fd = socket(s->source_addr.sa.sa_family, SOCK_DGRAM, 0)) != -1)
{
/* We need to set IPV6ONLY so we can use the same ports
for IPv4 and IPV6, otherwise, in restriced port situations,
we can end up with all our available ports in use for
one address family, and the other address family cannot be used. */
if (s->source_addr.sa.sa_family == AF_INET6)
{
int opt = 1;
if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &opt, sizeof(opt)) == -1)
{
close(fd);
return -1;
}
}
if (local_bind(fd, &s->source_addr, s->interface, s->ifindex, 0))
return fd;
@@ -2479,9 +2494,22 @@ int allocate_rfd(struct randfd_list **fdlp, struct server *serv)
{
static int finger = 0;
int i, j = 0;
int ports_full = 0;
struct randfd_list **up, *rfl, *found, **found_link;
struct randfd *rfd = NULL;
int fd = 0;
int ports_avail = 0;
/* We can't have more randomsocks for this AF available than ports in our port range,
so check that here, to avoid trying and failing to bind every port
in local_bind(), called from random_sock(). The actual check is below when
ports_avail != 0 */
if (daemon->max_port != 0)
{
ports_avail = daemon->max_port - daemon->min_port + 1;
if (ports_avail >= SMALL_PORT_RANGE)
ports_avail = 0;
}
/* If server has a pre-allocated fd, use that. */
if (serv->sfd)
@@ -2507,22 +2535,38 @@ int allocate_rfd(struct randfd_list **fdlp, struct server *serv)
*fdlp = found;
return found->rfd->fd;
}
/* check for all available ports in use. */
if (ports_avail != 0)
{
int ports_inuse;
for (ports_inuse = 0, i = 0; i < daemon->numrrand; i++)
if (daemon->randomsocks[i].refcount != 0 &&
daemon->randomsocks[i].serv->source_addr.sa.sa_family == serv->source_addr.sa.sa_family &&
++ports_inuse >= ports_avail)
{
ports_full = 1;
break;
}
}
/* limit the number of sockets we have open to avoid starvation of
(eg) TFTP. Once we have a reasonable number, randomness should be OK */
for (i = 0; i < daemon->numrrand; i++)
if (daemon->randomsocks[i].refcount == 0)
{
if ((fd = random_sock(serv)) != -1)
{
rfd = &daemon->randomsocks[i];
rfd->serv = serv;
rfd->fd = fd;
rfd->refcount = 1;
}
break;
}
if (!ports_full)
for (i = 0; i < daemon->numrrand; i++)
if (daemon->randomsocks[i].refcount == 0)
{
if ((fd = random_sock(serv)) != -1)
{
rfd = &daemon->randomsocks[i];
rfd->serv = serv;
rfd->fd = fd;
rfd->refcount = 1;
}
break;
}
/* No good existing. Need new link. */
if ((rfl = daemon->rfl_spare))
daemon->rfl_spare = rfl->next;