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Use the values of --min-port and --max-port in TCP connections.

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Rather that letting the kernel pick source ports, do it ourselves
so that the --min-port and --max-port parameters are be obeyed.
This commit is contained in:
Simon Kelley
2020-12-12 23:26:45 +00:00
parent 4ded96209e
commit a2a7e040b1
2 changed files with 39 additions and 5 deletions
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39
src/network.c
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@@ -1262,17 +1262,46 @@ int random_sock(int family)
int local_bind(int fd, union mysockaddr *addr, char *intname, unsigned int ifindex, int is_tcp)
{
union mysockaddr addr_copy = *addr;
unsigned short port;
int tries = 1, done = 0;
unsigned int ports_avail = ((unsigned short)daemon->max_port - (unsigned short)daemon->min_port) + 1;
if (addr_copy.sa.sa_family == AF_INET)
port = addr_copy.in.sin_port;
else
port = addr_copy.in6.sin6_port;
/* cannot set source _port_ for TCP connections. */
if (is_tcp)
port = 0;
/* Bind a random port within the range given by min-port and max-port */
if (port == 0)
{
if (addr_copy.sa.sa_family == AF_INET)
addr_copy.in.sin_port = 0;
else
addr_copy.in6.sin6_port = 0;
tries = ports_avail < 30 ? 3 * ports_avail : 100;
port = htons(daemon->min_port + (rand16() % ((unsigned short)ports_avail)));
}
if (bind(fd, (struct sockaddr *)&addr_copy, sa_len(&addr_copy)) == -1)
while (tries--)
{
if (addr_copy.sa.sa_family == AF_INET)
addr_copy.in.sin_port = port;
else
addr_copy.in6.sin6_port = port;
if (bind(fd, (struct sockaddr *)&addr_copy, sa_len(&addr_copy)) != -1)
{
done = 1;
break;
}
if (errno != EADDRINUSE && errno != EACCES)
return 0;
port = htons(daemon->min_port + (rand16() % ((unsigned short)ports_avail)));
}
if (!done)
return 0;
if (!is_tcp && ifindex > 0)