networkd: add link-sense and simplify state-machine a bit

This listens to rtnetlink for changes to IFF_UP and IFF_LOWER_UP (link sense). The latter
is simply logged at the moment, but will be useful once we add dhcp support.

4 files changed, 123 insertions, 42 deletions

diff --git a/src/network/networkd-bridge.c b/src/network/networkd-bridge.c
index e9dceab894..1704f65ee6 100644
--- a/src/network/networkd-bridge.c
+++ b/src/network/networkd-bridge.c
@@ -132,15 +132,17 @@ static int bridge_create_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userda
         r = sd_rtnl_message_get_errno(m);
         if (r < 0) {
                 log_warning("Bridge '%s' failed: %s", bridge->name, strerror(-r));
-                return bridge_enter_failed(bridge);
+                bridge_enter_failed(bridge);
+
+                return 1;
         }
 
         if (bridge->link)
-                return bridge_enter_ready(bridge);
+                bridge_enter_ready(bridge);
 
         bridge->state = BRIDGE_STATE_CREATED;
 
-        return 0;
+        return 1;
 }
 
 static int bridge_create(Bridge *bridge) {
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 09de862819..8c7b0fc1ee 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -128,28 +128,11 @@ static int link_enter_configured(Link *link) {
 }
 
 static int link_enter_failed(Link *link) {
-        log_warning("Could not configure link '%s'", link->ifname);
-
         link->state = LINK_STATE_FAILED;
 
         return 0;
 }
 
-static bool link_is_up(Link *link) {
-        return link->flags & IFF_UP;
-}
-
-static int link_enter_routes_set(Link *link) {
-        log_info("Routes set for link '%s'", link->ifname);
-
-        if (link_is_up(link))
-                return link_enter_configured(link);
-
-        link->state = LINK_STATE_ROUTES_SET;
-
-        return 0;
-}
-
 static int route_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
         Link *link = userdata;
         int r;
@@ -167,8 +150,10 @@ static int route_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
                 log_warning("Could not set route on interface '%s': %s",
                             link->ifname, strerror(-r));
 
-        if (link->rtnl_messages == 0)
-                return link_enter_routes_set(link);
+        if (link->rtnl_messages == 0) {
+                log_info("Routes set for link '%s'", link->ifname);
+                link_enter_configured(link);
+        }
 
         return 1;
 }
@@ -185,12 +170,14 @@ static int link_enter_set_routes(Link *link) {
         link->state = LINK_STATE_SET_ROUTES;
 
         if (!link->network->routes)
-                return link_enter_routes_set(link);
+                return link_enter_configured(link);
 
         LIST_FOREACH(routes, route, link->network->routes) {
                 r = route_configure(route, link, &route_handler);
-                if (r < 0)
+                if (r < 0) {
+                        log_warning("Could not set routes for link '%s'", link->ifname);
                         return link_enter_failed(link);
+                }
 
                 link->rtnl_messages ++;
         }
@@ -199,8 +186,6 @@ static int link_enter_set_routes(Link *link) {
 }
 
 static int link_enter_addresses_set(Link *link) {
-        log_info("Addresses set for link '%s'", link->ifname);
-
         link->state = LINK_STATE_ADDRESSES_SET;
 
         return link_enter_set_routes(link);
@@ -223,8 +208,10 @@ static int address_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
                 log_warning("Could not set address on interface '%s': %s",
                             link->ifname, strerror(-r));
 
-        if (link->rtnl_messages == 0)
+        if (link->rtnl_messages == 0) {
+                log_info("Addresses set for link '%s'", link->ifname);
                 link_enter_addresses_set(link);
+        }
 
         return 1;
 }
@@ -244,8 +231,10 @@ static int link_enter_set_addresses(Link *link) {
 
         LIST_FOREACH(addresses, address, link->network->addresses) {
                 r = address_configure(address, link, &address_handler);
-                if (r < 0)
+                if (r < 0) {
+                        log_warning("Could not set addresses for link '%s'", link->ifname);
                         return link_enter_failed(link);
+                }
 
                 link->rtnl_messages ++;
         }
@@ -253,21 +242,53 @@ static int link_enter_set_addresses(Link *link) {
         return 0;
 }
 
-static int link_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+static int link_get_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
         Link *link = userdata;
         int r;
 
         r = sd_rtnl_message_get_errno(m);
-        if (r < 0)
+        if (r < 0) {
                 log_warning("Could not bring up interface '%s': %s",
                             link->ifname, strerror(-r));
+                link_enter_failed(link);
+        }
 
-        link->flags |= IFF_UP;
+        return 1;
+}
 
-        log_info("Link '%s' is up", link->ifname);
+static int link_get(Link *link) {
+        _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+        int r;
 
-        if (link->state == LINK_STATE_ROUTES_SET)
-                return link_enter_configured(link);
+        assert(link);
+        assert(link->manager);
+        assert(link->manager->rtnl);
+
+        r = sd_rtnl_message_link_new(RTM_GETLINK, link->ifindex, 0, 0, &req);
+        if (r < 0) {
+                log_error("Could not allocate RTM_GETLINK message");
+                return r;
+        }
+
+        r = sd_rtnl_call_async(link->manager->rtnl, req, link_get_handler, link, 0, NULL);
+        if (r < 0) {
+                log_error("Could not send rtnetlink message: %s", strerror(-r));
+                return r;
+        }
+
+        return 0;
+}
+
+static int link_up_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+        Link *link = userdata;
+        int r;
+
+        r = sd_rtnl_message_get_errno(m);
+        if (r < 0) {
+                log_warning("Could not bring up interface '%s': %s",
+                            link->ifname, strerror(-r));
+                link_enter_failed(link);
+        }
 
         return 1;
 }
@@ -286,7 +307,7 @@ static int link_up(Link *link) {
                 return r;
         }
 
-        r = sd_rtnl_call_async(link->manager->rtnl, req, link_handler, link, 0, NULL);
+        r = sd_rtnl_call_async(link->manager->rtnl, req, link_up_handler, link, 0, NULL);
         if (r < 0) {
                 log_error("Could not send rtnetlink message: %s", strerror(-r));
                 return r;
@@ -298,12 +319,12 @@ static int link_up(Link *link) {
 static int link_enter_bridge_joined(Link *link) {
         int r;
 
+        link->state = LINK_STATE_BRIDGE_JOINED;
+
         r = link_up(link);
         if (r < 0)
                 return link_enter_failed(link);
 
-        link->state = LINK_STATE_BRIDGE_JOINED;
-
         return link_enter_set_addresses(link);
 }
 
@@ -318,8 +339,11 @@ static int bridge_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
 
         r = sd_rtnl_message_get_errno(m);
         if (r < 0)
-                log_warning("Could not join interface '%s' to bridge: %s",
-                            link->ifname, strerror(-r));
+                log_warning("Could not join interface '%s' to bridge '%s': %s",
+                            link->ifname, link->network->bridge->name, strerror(-r));
+        else
+                log_info("Join interface '%s' to bridge: %s",
+                            link->ifname, link->network->bridge->name);
 
         link_enter_bridge_joined(link);
 
@@ -338,8 +362,11 @@ static int link_enter_join_bridge(Link *link) {
         link->state = LINK_STATE_JOIN_BRIDGE;
 
         r = bridge_join(link->network->bridge, link, &bridge_handler);
-        if (r < 0)
+        if (r < 0) {
+                log_warning("Could not join link '%s' to bridge '%s'", link->ifname,
+                            link->network->bridge->name);
                 return link_enter_failed(link);
+        }
 
         return 0;
 }
@@ -347,9 +374,31 @@ static int link_enter_join_bridge(Link *link) {
 int link_configure(Link *link) {
         int r;
 
+        r = link_get(link);
+        if (r < 0)
+                return link_enter_failed(link);
+
         r = link_enter_join_bridge(link);
         if (r < 0)
                 return link_enter_failed(link);
 
         return 0;
 }
+
+int link_update_flags(Link *link, unsigned flags) {
+        assert(link);
+
+        if (link->flags & IFF_UP && !(flags & IFF_UP))
+                log_info("Interface '%s' is down", link->ifname);
+        else if (!(link->flags & IFF_UP) && flags & IFF_UP)
+                log_info("Interface '%s' is up", link->ifname);
+
+        if (link->flags & IFF_LOWER_UP && !(flags & IFF_LOWER_UP))
+                log_info("Interface '%s' is disconnected", link->ifname);
+        else if (!(link->flags & IFF_LOWER_UP) && flags & IFF_LOWER_UP)
+                log_info("Interface '%s' is connected", link->ifname);
+
+        link->flags = flags;
+
+        return 0;
+}
diff --git a/src/network/networkd-manager.c b/src/network/networkd-manager.c
index 1dc7e88dfd..c8ec23970b 100644
--- a/src/network/networkd-manager.c
+++ b/src/network/networkd-manager.c
@@ -35,7 +35,7 @@ int manager_new(Manager **ret) {
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_open(0, &m->rtnl);
+        r = sd_rtnl_open(RTMGRP_LINK | RTMGRP_IPV4_IFADDR, &m->rtnl);
         if (r < 0)
                 return r;
 
@@ -243,6 +243,31 @@ int manager_udev_listen(Manager *m) {
         return 0;
 }
 
+static int manager_rtnl_process_link(sd_rtnl *rtnl, sd_rtnl_message *message, void *userdata) {
+        Manager *m = userdata;
+        Link *link;
+        unsigned flags;
+        int r, ifindex;
+
+        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
+        if (r < 0)
+                return 0;
+
+        link = hashmap_get(m->links, &ifindex);
+        if (!link)
+                return 0;
+
+        r = sd_rtnl_message_link_get_flags(message, &flags);
+        if (r < 0)
+                return 0;
+
+        r = link_update_flags(link, flags);
+        if (r < 0)
+                return 0;
+
+        return 1;
+}
+
 int manager_rtnl_listen(Manager *m) {
         int r;
 
@@ -250,5 +275,9 @@ int manager_rtnl_listen(Manager *m) {
         if (r < 0)
                 return r;
 
+        r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, &manager_rtnl_process_link, m);
+        if (r < 0)
+                return r;
+
         return 0;
 }
diff --git a/src/network/networkd.h b/src/network/networkd.h
index 1ab8a55a88..075cc1275e 100644
--- a/src/network/networkd.h
+++ b/src/network/networkd.h
@@ -138,7 +138,6 @@ typedef enum LinkState {
         LINK_STATE_SET_ADDRESSES,
         LINK_STATE_ADDRESSES_SET,
         LINK_STATE_SET_ROUTES,
-        LINK_STATE_ROUTES_SET,
         LINK_STATE_CONFIGURED,
         LINK_STATE_FAILED,
         _LINK_STATE_MAX,
@@ -264,5 +263,7 @@ void link_free(Link *link);
 int link_add(Manager *manager, struct udev_device *device);
 int link_configure(Link *link);
 
+int link_update_flags(Link *link, unsigned flags);
+
 DEFINE_TRIVIAL_CLEANUP_FUNC(Link*, link_free);
 #define _cleanup_link_free_ _cleanup_(link_freep)