network/ipv4ll: use a foreign IPv4LL address when KeepConfiguration=dhcp

This is similar to what we do for DHCPv4 address, but for IPv4LL
address.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/network/networkd-ipv4ll.c b/src/network/networkd-ipv4ll.c
index 7398cefe77..9682d0d874 100644
--- a/src/network/networkd-ipv4ll.c
+++ b/src/network/networkd-ipv4ll.c
@@ -175,6 +175,8 @@ static int ipv4ll_check_mac(sd_ipv4ll *ll, const struct ether_addr *mac, void *u
 }
 
 static int ipv4ll_set_address(Link *link) {
+        int r;
+
         assert(link);
         assert(link->network);
         assert(link->ipv4ll);
@@ -193,6 +195,27 @@ static int ipv4ll_set_address(Link *link) {
         if (in4_addr_is_set(&link->network->ipv4ll_start_address))
                 return sd_ipv4ll_set_address(link->ipv4ll, &link->network->ipv4ll_start_address);
 
+        /* 3. If KeepConfiguration=dhcp, use a foreign IPv4LL address. */
+        if (!FLAGS_SET(link->network->keep_configuration, KEEP_CONFIGURATION_DHCP))
+                return 0;
+
+        SET_FOREACH(a, link->addresses) {
+                if (a->source != NETWORK_CONFIG_SOURCE_FOREIGN)
+                        continue;
+                if (a->family != AF_INET)
+                        continue;
+                if (!in4_addr_is_link_local_dynamic(&a->in_addr.in))
+                        continue;
+
+                r = sd_ipv4ll_set_address(link->ipv4ll, &a->in_addr.in);
+                if (r < 0)
+                        return r;
+
+                /* Make sure the address is not removed by link_drop_unmanaged_addresses(). */
+                a->source = NETWORK_CONFIG_SOURCE_IPV4LL;
+                return 0;
+        }
+
         return 0;
 }