network: Add "route_localnet" sysctl support

4 files changed, 19 insertions, 0 deletions

diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index f7dd21b73d..348c27d4e1 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -120,6 +120,7 @@ Network.IPv6HopLimit,                        config_parse_int,
 Network.IPv6ProxyNDP,                        config_parse_tristate,                                    0,                             offsetof(Network, ipv6_proxy_ndp)
 Network.IPv6MTUBytes,                        config_parse_mtu,                                         AF_INET6,                      offsetof(Network, ipv6_mtu)
 Network.IPv4AcceptLocal,                     config_parse_tristate,                                    0,                             offsetof(Network, ipv4_accept_local)
+Network.IPv4RouteLocalnet,                   config_parse_tristate,                                    0,                             offsetof(Network, ipv4_route_localnet)
 Network.ActiveSlave,                         config_parse_bool,                                        0,                             offsetof(Network, active_slave)
 Network.PrimarySlave,                        config_parse_bool,                                        0,                             offsetof(Network, primary_slave)
 Network.IPv4ProxyARP,                        config_parse_tristate,                                    0,                             offsetof(Network, proxy_arp)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index eebbe19527..352a57325a 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -422,6 +422,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
                 .ipv6ll_address_gen_mode = _IPV6_LINK_LOCAL_ADDRESS_GEN_MODE_INVALID,
 
                 .ipv4_accept_local = -1,
+                .ipv4_route_localnet = -1,
                 .ipv6_privacy_extensions = IPV6_PRIVACY_EXTENSIONS_NO,
                 .ipv6_accept_ra = -1,
                 .ipv6_dad_transmits = -1,
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 4a3d126b7b..fc3d5a8a7f 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -253,6 +253,7 @@ struct Network {
         /* sysctl settings */
         AddressFamily ip_forward;
         int ipv4_accept_local;
+        int ipv4_route_localnet;
         int ipv6_dad_transmits;
         int ipv6_hop_limit;
         int proxy_arp;
diff --git a/src/network/networkd-sysctl.c b/src/network/networkd-sysctl.c
index 377fdac722..11681286e0 100644
--- a/src/network/networkd-sysctl.c
+++ b/src/network/networkd-sysctl.c
@@ -173,6 +173,18 @@ static int link_set_ipv4_accept_local(Link *link) {
         return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "accept_local", link->network->ipv4_accept_local > 0);
 }
 
+static int link_set_ipv4_route_localnet(Link *link) {
+        assert(link);
+
+        if (link->flags & IFF_LOOPBACK)
+                return 0;
+
+        if (link->network->ipv4_route_localnet < 0)
+                return 0;
+
+        return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "route_localnet", link->network->ipv4_route_localnet > 0);
+}
+
 int link_set_sysctl(Link *link) {
         int r;
 
@@ -216,6 +228,10 @@ int link_set_sysctl(Link *link) {
         if (r < 0)
                 log_link_warning_errno(link, r, "Cannot set IPv4 accept_local flag for interface, ignoring: %m");
 
+        r = link_set_ipv4_route_localnet(link);
+        if (r < 0)
+                log_link_warning_errno(link, r, "Cannot set IPv4 route_localnet flag for interface, ignoring: %m");
+
         /* If promote_secondaries is not set, DHCP will work only as long as the IP address does not
          * changes between leases. The kernel will remove all secondary IP addresses of an interface
          * otherwise. The way systemd-networkd works is that the new IP of a lease is added as a