networkd: Add bridge port path cost

This patch add support to specify path cost of the
bridge port to be configured via conf file.

Exampe: conf

file: br.netdev

[NetDev]
Name=br-test
Kind=bridge

file: br.network
[Match]
Name=em1

[Network]
Bridge=br-test

[BridgePort]
Cost=332

 bridge link
2: em1 state UP : <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master
br-test state disabled priority 32 cost 332

1 files changed, 93 insertions, 0 deletions

diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 2eb0925d73..a4f8c59e09 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -685,6 +685,27 @@ int link_address_drop_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata)
         return 1;
 }
 
+static int link_set_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+        _cleanup_link_unref_ Link *link = userdata;
+        int r;
+
+        log_debug_link(link, "set link");
+
+        r = sd_rtnl_message_get_errno(m);
+        if (r < 0 && r != -EEXIST) {
+                log_struct_link(LOG_ERR, link,
+                                "MESSAGE=%-*s: could not join netdev: %s",
+                                IFNAMSIZ,
+                                link->ifname, strerror(-r),
+                                "ERRNO=%d", -r,
+                                NULL);
+                link_enter_failed(link);
+                return 1;
+        }
+
+        return 0;
+}
+
 static int set_hostname_handler(sd_bus *bus, sd_bus_message *m, void *userdata,
                                 sd_bus_error *ret_error) {
         _cleanup_link_unref_ Link *link = userdata;
@@ -802,6 +823,69 @@ int link_set_mtu(Link *link, uint32_t mtu) {
         return 0;
 }
 
+static int link_set_bridge(Link *link) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+        int r;
+
+        assert(link);
+        assert(link->network);
+
+        if(link->network->cost == 0)
+                return 0;
+
+        r = sd_rtnl_message_new_link(link->manager->rtnl, &req,
+                                     RTM_SETLINK, link->ifindex);
+        if (r < 0) {
+                log_error_link(link, "Could not allocate RTM_SETLINK message");
+                return r;
+        }
+
+        r = sd_rtnl_message_link_set_family(req, PF_BRIDGE);
+        if (r < 0) {
+                log_error_link(link,
+                               "Could not set message family %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_open_container(req, IFLA_PROTINFO);
+        if (r < 0) {
+                log_error_link(link,
+                               "Could not append IFLA_PROTINFO attribute: %s",
+                               strerror(-r));
+                return r;
+        }
+
+        if(link->network->cost != 0) {
+                r = sd_rtnl_message_append_u32(req, IFLA_BRPORT_COST, link->network->cost);
+                if (r < 0) {
+                        log_error_link(link,
+                                       "Could not append IFLA_BRPORT_COST attribute: %s",
+                                       strerror(-r));
+                        return r;
+                }
+        }
+
+        r = sd_rtnl_message_close_container(req);
+        if (r < 0) {
+                log_error_link(link,
+                               "Could not append IFLA_LINKINFO attribute: %s",
+                               strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_call_async(link->manager->rtnl, req, link_set_handler, link, 0, NULL);
+        if (r < 0) {
+                log_error_link(link,
+                               "Could not send rtnetlink message: %s",
+                               strerror(-r));
+                return r;
+        }
+
+        link_ref(link);
+
+        return r;
+}
+
 static void dhcp6_handler(sd_dhcp6_client *client, int event, void *userdata) {
         Link *link = userdata;
 
@@ -1037,6 +1121,15 @@ static int link_joined(Link *link) {
                 }
         }
 
+        if(link->network->bridge) {
+                r = link_set_bridge(link);
+                if (r < 0) {
+                        log_error_link(link,
+                                       "Could not set bridge message: %s",
+                                       strerror(-r));
+                }
+        }
+
         return link_enter_set_addresses(link);
 }