ippool: Implement and use blacklist instead of blindly using IPPOOL_NOGATEWAY
Commit dda21ed7d4a897c9284c69175d0da598598eae40 modified previous calls
to ippool_new() removing the pass of flags to avoid allocating certain
problematic IPs from the pool to MS, such as the network, gateway and
broadcast IPs.
Today I did some unsucessful tests with osmo-ggsn with a pool "ip prefix
dynamic 176.16.222.0/24", and thus IP 176.16.222.0 was being assigned to
the MS. De-capsulated DNS packets were received in the tun interface,
but the Linux system in there was unable to correctly forward the
packets to the gateway interface connected to the Internet. However,
adding a second MS which got 176.16.222.1 had its packets forwarded
correctly.
However, previous implementation relies on flag IPPOOL_NOGATEWAY flag to
blindly blacklist first IP after the network ip (ie, .0 and .1 are
removed), which limits the IP reserved for the tun device to be .1. If a
different IP in the range is assigned, it may cause issues. As a result,
a blacklist is introduced in this commit to dynamically fetch the tun IP
address and exlucde it from the pool of available IPs.
Change-Id: I8e91f7280d60490c858a769dd578c1c8e54e9243
diff --git a/lib/ippool.c b/lib/ippool.c
index 03323e2..55a41d0 100644
--- a/lib/ippool.c
+++ b/lib/ippool.c
@@ -184,9 +184,19 @@
}
}
+static bool addr_in_prefix_list(struct in46_addr *addr, struct in46_prefix *list, size_t list_size)
+{
+ int i;
+ for (i = 0; i < list_size; i++) {
+ if (in46a_prefix_equal(addr, &list[i].addr))
+ return true;
+ }
+ return false;
+}
+
/* Create new address pool */
int ippool_new(struct ippool_t **this, const struct in46_prefix *dyn, const struct in46_prefix *stat,
- int flags)
+ int flags, struct in46_prefix *blacklist, size_t blacklist_size)
{
/* Parse only first instance of pool for now */
@@ -210,18 +220,16 @@
if (addr.len == sizeof(struct in6_addr))
addr.len = 64/8;
- /* Set IPPOOL_NONETWORK if IPPOOL_NOGATEWAY is set */
- if (flags & IPPOOL_NOGATEWAY) {
- flags |= IPPOOL_NONETWORK;
- }
-
dynsize = (1 << (addr.len*8 - addrprefixlen));
if (flags & IPPOOL_NONETWORK) /* Exclude network address from pool */
dynsize--;
- if (flags & IPPOOL_NOGATEWAY) /* Exclude gateway address from pool */
- dynsize--;
if (flags & IPPOOL_NOBROADCAST) /* Exclude broadcast address from pool */
dynsize--;
+ /* Exclude included blacklist addresses from pool */
+ for (i = 0; i < blacklist_size; i++) {
+ if (in46a_within_mask(&blacklist[i].addr, &addr, addrprefixlen))
+ dynsize--;
+ }
}
if (!stat || stat->addr.len == 0) {
@@ -278,13 +286,17 @@
(*this)->firstdyn = NULL;
(*this)->lastdyn = NULL;
- if (flags & IPPOOL_NOGATEWAY) {
- in46a_inc(&addr);
- in46a_inc(&addr);
- } else if (flags & IPPOOL_NONETWORK) {
+ if (flags & IPPOOL_NONETWORK) {
in46a_inc(&addr);
}
for (i = 0; i < dynsize; i++) {
+ if (addr_in_prefix_list(&addr, blacklist, blacklist_size)) {
+ SYS_ERR(DIP, LOGL_DEBUG, 0,
+ "addr blacklisted from pool: %s", in46a_ntoa(&addr));
+ in46a_inc(&addr);
+ i--;
+ continue;
+ }
(*this)->member[i].addr = addr;
in46a_inc(&addr);