1 files changed, 175 insertions, 0 deletions
diff --git a/src/network/networkd-address-pool.c b/src/network/networkd-address-pool.c
new file mode 100644
index 0000000..51f092a
--- /dev/null
+++ b/src/network/networkd-address-pool.c
@@ -0,0 +1,175 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "networkd-address-pool.h"
+#include "networkd-address.h"
+#include "networkd-manager.h"
+#include "set.h"
+#include "string-util.h"
+
+#define RANDOM_PREFIX_TRIAL_MAX  1024
+
+static int address_pool_new(
+                Manager *m,
+                int family,
+                const union in_addr_union *u,
+                unsigned prefixlen) {
+
+        _cleanup_free_ AddressPool *p = NULL;
+        int r;
+
+        assert(m);
+        assert(u);
+
+        p = new(AddressPool, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (AddressPool) {
+                .manager = m,
+                .family = family,
+                .prefixlen = prefixlen,
+                .in_addr = *u,
+        };
+
+        r = ordered_set_ensure_put(&m->address_pools, NULL, p);
+        if (r < 0)
+                return r;
+
+        TAKE_PTR(p);
+        return 0;
+}
+
+static int address_pool_new_from_string(
+                Manager *m,
+                int family,
+                const char *p,
+                unsigned prefixlen) {
+
+        union in_addr_union u;
+        int r;
+
+        assert(m);
+        assert(p);
+
+        r = in_addr_from_string(family, p, &u);
+        if (r < 0)
+                return r;
+
+        return address_pool_new(m, family, &u, prefixlen);
+}
+
+int address_pool_setup_default(Manager *m) {
+        int r;
+
+        assert(m);
+
+        /* Add in the well-known private address ranges. */
+        r = address_pool_new_from_string(m, AF_INET6, "fd00::", 8);
+        if (r < 0)
+                return r;
+
+        r = address_pool_new_from_string(m, AF_INET, "192.168.0.0", 16);
+        if (r < 0)
+                return r;
+
+        r = address_pool_new_from_string(m, AF_INET, "172.16.0.0", 12);
+        if (r < 0)
+                return r;
+
+        r = address_pool_new_from_string(m, AF_INET, "10.0.0.0", 8);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static bool address_pool_prefix_is_taken(
+                AddressPool *p,
+                const union in_addr_union *u,
+                unsigned prefixlen) {
+
+        Link *l;
+        Network *n;
+
+        assert(p);
+        assert(u);
+
+        HASHMAP_FOREACH(l, p->manager->links_by_index) {
+                Address *a;
+
+                /* Don't clash with assigned addresses */
+                SET_FOREACH(a, l->addresses) {
+                        if (a->family != p->family)
+                                continue;
+
+                        if (in_addr_prefix_intersect(p->family, u, prefixlen, &a->in_addr, a->prefixlen))
+                                return true;
+                }
+        }
+
+        /* And don't clash with configured but un-assigned addresses either */
+        ORDERED_HASHMAP_FOREACH(n, p->manager->networks) {
+                Address *a;
+
+                ORDERED_HASHMAP_FOREACH(a, n->addresses_by_section) {
+                        if (a->family != p->family)
+                                continue;
+
+                        if (in_addr_prefix_intersect(p->family, u, prefixlen, &a->in_addr, a->prefixlen))
+                                return true;
+                }
+        }
+
+        return false;
+}
+
+static int address_pool_acquire_one(AddressPool *p, int family, unsigned prefixlen, union in_addr_union *found) {
+        union in_addr_union u;
+        int r;
+
+        assert(p);
+        assert(prefixlen > 0);
+        assert(found);
+
+        if (p->family != family)
+                return 0;
+
+        if (p->prefixlen >= prefixlen)
+                return 0;
+
+        u = p->in_addr;
+
+        for (unsigned i = 0; i < RANDOM_PREFIX_TRIAL_MAX; i++) {
+                r = in_addr_random_prefix(p->family, &u, p->prefixlen, prefixlen);
+                if (r <= 0)
+                        return r;
+
+                if (!address_pool_prefix_is_taken(p, &u, prefixlen)) {
+                        log_debug("Found range %s", IN_ADDR_PREFIX_TO_STRING(p->family, &u, prefixlen));
+
+                        *found = u;
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
+int address_pool_acquire(Manager *m, int family, unsigned prefixlen, union in_addr_union *found) {
+        AddressPool *p;
+        int r;
+
+        assert(m);
+        assert(IN_SET(family, AF_INET, AF_INET6));
+        assert(prefixlen > 0);
+        assert(found);
+
+        ORDERED_SET_FOREACH(p, m->address_pools) {
+                r = address_pool_acquire_one(p, family, prefixlen, found);
+                if (r != 0)
+                        return r;
+        }
+
+        return 0;
+}