network: add io.systemd.Network.Link.Renew() Varlink method

The handler calls dhcp4_renew() and logs a warning on failure.

Co-developed-by: Claude Opus 4.6 <noreply@anthropic.com>

src/network/networkd-link-varlink.c

@@ -4,6 +4,7 @@
 
 #include "bus-polkit.h"
 #include "json-util.h"
+#include "networkd-dhcp4.h"
 #include "networkd-link.h"
 #include "networkd-link-varlink.h"
 #include "networkd-manager.h"
@@ -100,3 +101,30 @@ int vl_method_link_up(sd_varlink *vlink, sd_json_variant *parameters, sd_varlink
 int vl_method_link_down(sd_varlink *vlink, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
         return vl_method_link_up_or_down(vlink, parameters, userdata, /* up= */ false);
 }
+
+int vl_method_link_renew(sd_varlink *vlink, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
+        Manager *manager = ASSERT_PTR(userdata);
+        Link *link;
+        int r;
+
+        assert(vlink);
+
+        r = dispatch_link(vlink, parameters, manager, DISPATCH_LINK_POLKIT | DISPATCH_LINK_MANDATORY, &link);
+        if (r != 0)
+                return r;
+
+        r = varlink_verify_polkit_async(
+                        vlink,
+                        manager->bus,
+                        "org.freedesktop.network1.renew",
+                        /* details= */ NULL,
+                        &manager->polkit_registry);
+        if (r <= 0)
+                return r;
+
+        r = dhcp4_renew(link);
+        if (r < 0)
+                return log_link_warning_errno(link, r, "Failed to renew DHCPv4 lease: %m");
+
+        return sd_varlink_reply(vlink, NULL);
+}

src/network/networkd-link-varlink.h

@@ -12,3 +12,4 @@ int dispatch_link(sd_varlink *vlink, sd_json_variant *parameters, Manager *manag
 
 int vl_method_link_up(sd_varlink *vlink, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
 int vl_method_link_down(sd_varlink *vlink, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);
+int vl_method_link_renew(sd_varlink *vlink, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata);

src/network/networkd-manager-varlink.c

@@ -273,6 +273,7 @@ int manager_varlink_init(Manager *m, int fd) {
                         "io.systemd.Network.SetPersistentStorage", vl_method_set_persistent_storage,
                         "io.systemd.Network.Link.Up",              vl_method_link_up,
                         "io.systemd.Network.Link.Down",            vl_method_link_down,
+                        "io.systemd.Network.Link.Renew",           vl_method_link_renew,
                         "io.systemd.service.Ping",                 varlink_method_ping,
                         "io.systemd.service.SetLogLevel",          varlink_method_set_log_level,
                         "io.systemd.service.GetEnvironment",       varlink_method_get_environment);

src/shared/varlink-io.systemd.Network.Link.c

@@ -19,10 +19,17 @@ static SD_VARLINK_DEFINE_METHOD(
                 VARLINK_NETWORK_INTERFACE_INPUTS,
                 VARLINK_DEFINE_POLKIT_INPUT);
 
+static SD_VARLINK_DEFINE_METHOD(
+                Renew,
+                VARLINK_NETWORK_INTERFACE_INPUTS,
+                VARLINK_DEFINE_POLKIT_INPUT);
+
 SD_VARLINK_DEFINE_INTERFACE(
                 io_systemd_Network_Link,
                 "io.systemd.Network.Link",
                 SD_VARLINK_SYMBOL_COMMENT("Bring the specified link up."),
                 &vl_method_Up,
                 SD_VARLINK_SYMBOL_COMMENT("Bring the specified link down."),
-                &vl_method_Down);
+                &vl_method_Down,
+                SD_VARLINK_SYMBOL_COMMENT("Renew DHCP leases on the specified link."),
+                &vl_method_Renew);