networkd: tie links to rtnl rather than udev

This essentially swaps the roles of rtnl and udev in networkd. After this
change libudev is only used for waiting for udev to initialize devices and
to get udev-specific information needed for some [Match] attributes.

This in particular simplifies the code in containers where udev is not really
useful, but also simplifies things and reduces round-trips in the non-container
case.

1 files changed, 97 insertions, 87 deletions

diff --git a/src/network/networkd-manager.c b/src/network/networkd-manager.c
index d903d0d60e..4c1987daa8 100644
--- a/src/network/networkd-manager.c
+++ b/src/network/networkd-manager.c
@@ -29,6 +29,8 @@
 #include "mkdir.h"
 #include "virt.h"
 
+#include "sd-rtnl.h"
+
 const char* const network_dirs[] = {
         "/etc/systemd/network",
         "/run/systemd/network",
@@ -96,18 +98,14 @@ int manager_new(Manager **ret) {
         if (r < 0)
                 return r;
 
-        m->udev = udev_new();
-        if (!m->udev)
-                return -ENOMEM;
-
         /* udev does not initialize devices inside containers,
          * so we rely on them being already initialized before
          * entering the container */
-        if (detect_container(NULL) > 0) {
-                m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "kernel");
-                if (!m->udev_monitor)
+        if (detect_container(NULL) <= 0) {
+                m->udev = udev_new();
+                if (!m->udev)
                         return -ENOMEM;
-        } else {
+
                 m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev");
                 if (!m->udev_monitor)
                         return -ENOMEM;
@@ -182,15 +180,30 @@ bool manager_should_reload(Manager *m) {
         return paths_check_timestamp(network_dirs, &m->network_dirs_ts_usec, false);
 }
 
-static int manager_process_link(Manager *m, struct udev_device *device) {
+static int manager_udev_process_link(Manager *m, struct udev_device *device) {
         Link *link = NULL;
         int r;
 
         assert(m);
         assert(device);
 
-        link_get(m, udev_device_get_ifindex(device), &link);
+        if (!streq_ptr(udev_device_get_action(device), "add"))
+                return 0;
+
+        r = link_get(m, udev_device_get_ifindex(device), &link);
+        if (r < 0)
+                return r;
+
+        if (!link)
+                return 0;
+
+        r = link_initialized(link, device);
+        if (r < 0)
+                return r;
 
+        return 0;
+}
+/*
         if (streq_ptr(udev_device_get_action(device), "remove")) {
                 log_debug("%s: link removed", udev_device_get_sysname(device));
 
@@ -215,45 +228,87 @@ static int manager_process_link(Manager *m, struct udev_device *device) {
 
         return 0;
 }
+*/
+static int manager_rtnl_process_link(sd_rtnl *rtnl, sd_rtnl_message *message, void *userdata) {
+        Manager *m = userdata;
+        Link *link = NULL;
+        char *name;
+        int r, ifindex;
 
-int manager_udev_enumerate_links(Manager *m) {
-        _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
-        struct udev_list_entry *item = NULL, *first = NULL;
-        int r;
-
+        assert(rtnl);
+        assert(message);
         assert(m);
 
-        e = udev_enumerate_new(m->udev);
-        if (!e)
-                return -ENOMEM;
+        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
+        if (r < 0 || ifindex <= 0) {
+                log_warning("rtnl: received link message without valid ifindex");
+                return 0;
+        }
+
+        link_get(m, ifindex, &link);
+        if (!link) {
+                /* link is new, so add it */
+                r = link_add(m, message, &link);
+                if (r < 0) {
+                        log_debug("could not add new link");
+                        return 0;
+                }
+        }
 
-        r = udev_enumerate_add_match_subsystem(e, "net");
+        r = sd_rtnl_message_read_string(message, IFLA_IFNAME, &name);
         if (r < 0)
-                return r;
+                log_warning("rtnl: received link message without valid ifname");
+        else {
+                NetDev *netdev;
 
-        /* udev does not initialize devices inside containers,
-         * so we rely on them being already initialized before
-         * entering the container */
-        if (detect_container(NULL) <= 0) {
-                r = udev_enumerate_add_match_is_initialized(e);
-                if (r < 0)
-                        return r;
+                r = netdev_get(m, name, &netdev);
+                if (r >= 0) {
+                        r = netdev_set_ifindex(netdev, message);
+                        if (r < 0) {
+                                log_debug("could not set ifindex on netdev");
+                                return 0;
+                        }
+                }
         }
 
-        r = udev_enumerate_scan_devices(e);
+        r = link_update(link, message);
+        if (r < 0)
+                return 0;
+
+        return 1;
+}
+
+int manager_rtnl_enumerate_links(Manager *m) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL;
+        sd_rtnl_message *link;
+        int r, k;
+
+        assert(m);
+        assert(m->rtnl);
+
+        r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
+        if (r < 0)
+                return r;
+
+        r = sd_rtnl_message_request_dump(req, true);
         if (r < 0)
                 return r;
 
-        first = udev_enumerate_get_list_entry(e);
-        udev_list_entry_foreach(item, first) {
-                _cleanup_udev_device_unref_ struct udev_device *d = NULL;
-                int k;
+        r = sd_rtnl_call(m->rtnl, req, 0, &reply);
+        if (r < 0)
+                return r;
 
-                d = udev_device_new_from_syspath(m->udev, udev_list_entry_get_name(item));
-                if (!d)
-                        return -ENOMEM;
+        for (link = reply; link; link = sd_rtnl_message_next(link)) {
+                uint16_t type;
+
+                k = sd_rtnl_message_get_type(link, &type);
+                if (k < 0)
+                        return k;
+
+                if (type != RTM_NEWLINK)
+                        continue;
 
-                k = manager_process_link(m, d);
+                k = manager_rtnl_process_link(m->rtnl, link, m);
                 if (k < 0)
                         r = k;
         }
@@ -270,13 +325,18 @@ static int manager_dispatch_link_udev(sd_event_source *source, int fd, uint32_t
         if (!device)
                 return -ENOMEM;
 
-        manager_process_link(m, device);
+        manager_udev_process_link(m, device);
         return 0;
 }
 
 int manager_udev_listen(Manager *m) {
         int r;
 
+        if (detect_container(NULL) > 0)
+                return 0;
+
+        assert(m->udev_monitor);
+
         r = udev_monitor_filter_add_match_subsystem_devtype(m->udev_monitor, "net", NULL);
         if (r < 0) {
                 log_error("Could not add udev monitor filter: %s", strerror(-r));
@@ -300,56 +360,6 @@ 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;
-        char *name;
-        int r, ifindex;
-
-        assert(rtnl);
-        assert(message);
-        assert(m);
-
-        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
-        if (r < 0 || ifindex <= 0) {
-                log_warning("received RTM_NEWLINK message without valid ifindex");
-                return 0;
-        }
-
-        r = sd_rtnl_message_read_string(message, IFLA_IFNAME, &name);
-        if (r < 0)
-                log_warning("received RTM_NEWLINK message without valid ifname");
-        else {
-                NetDev *netdev;
-
-                r = netdev_get(m, name, &netdev);
-                if (r >= 0) {
-                        netdev_set_ifindex(netdev, message);
-                        r = sd_rtnl_message_rewind(message);
-                        if (r < 0) {
-                                log_debug("could not rewind rtnl message");
-                                return 0;
-                        }
-                }
-        }
-
-        r = link_get(m, ifindex, &link);
-        if (r < 0) {
-                log_debug("received RTM_NEWLINK message for untracked ifindex %d", ifindex);
-                return 0;
-        }
-
-        /* only track the status of links we want to manage */
-        if (link->network) {
-                r = link_update(link, message);
-                if (r < 0)
-                        return 0;
-        } else
-                log_debug("%s: received RTM_NEWLINK message for unmanaged link", link->ifname);
-
-        return 1;
-}
-
 int manager_rtnl_listen(Manager *m) {
         int r;