From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 9 Feb 2023 19:46:25 +0000 (+0000)
Subject: networkd: Connect to the kernel's netlink interface
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e62b300ef78484b882d2da8683ebe79896523a13;p=network.git

networkd: Connect to the kernel's netlink interface

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/networkd/daemon.c b/src/networkd/daemon.c
index 960fd96c..13e12571 100644
--- a/src/networkd/daemon.c
+++ b/src/networkd/daemon.c
@@ -25,6 +25,7 @@
 #include <systemd/sd-daemon.h>
 #include <systemd/sd-device.h>
 #include <systemd/sd-event.h>
+#include <systemd/sd-netlink.h>
 
 #include "bus.h"
 #include "config.h"
@@ -45,6 +46,9 @@ struct nw_daemon {
 	// Event Loop
 	sd_event* loop;
 
+	// Netlink Connection
+	sd_netlink* rtnl;
+
 	// DBus Connection
 	sd_bus* bus;
 
@@ -185,6 +189,47 @@ static int nw_start_device_monitor(struct nw_daemon* daemon) {
 	return 0;
 }
 
+static int _rtnl_dummy(sd_netlink* rtnl, sd_netlink_message* message, void* data) {
+	DEBUG("_rtnl_dummy called\n");
+
+	return 0;
+}
+
+static int nw_daemon_connect_rtnl(struct nw_daemon* daemon, int fd) {
+	int r;
+
+	// Connect to Netlink
+	r = sd_netlink_open(&daemon->rtnl);
+	if (r < 0) {
+		ERROR("Could not connect to the kernel's netlink interface: %m\n");
+		return 1;
+	}
+
+	// Increase the receive buffer
+	r = sd_netlink_increase_rxbuf(daemon->rtnl, RCVBUF_SIZE);
+	if (r < 0) {
+		ERROR("Could not increase receive buffer for the netlink socket: %m\n");
+		return 1;
+	}
+
+	// Connect it to the event loop
+	r = sd_netlink_attach_event(daemon->rtnl, daemon->loop, 0);
+	if (r < 0) {
+		ERROR("Could not connect the netlink socket to the event loop: %m\n");
+		return 1;
+	}
+
+	// Register callback for new interfaces
+	r = sd_netlink_add_match(daemon->rtnl, NULL, RTM_NEWLINK, _rtnl_dummy, NULL,
+			daemon, "networkd-RTM_NEWLINK");
+	if (r < 0) {
+		ERROR("Could not register RTM_NEWLINK: %m\n");
+		return 1;
+	}
+
+	return 0;
+}
+
 static int nw_daemon_setup(struct nw_daemon* daemon) {
 	int r;
 
@@ -198,6 +243,11 @@ static int nw_daemon_setup(struct nw_daemon* daemon) {
 	if (r)
 		return r;
 
+	// Connect to the kernel's netlink interface
+	r = nw_daemon_connect_rtnl(daemon, 0);
+	if (r)
+		return r;
+
 	// Connect to the system bus
 	r = nw_bus_connect(daemon->bus, daemon->loop, daemon);
 	if (r)