networkd: introduce ipip tunnel

This patch enables basic ipip tunnel support.
It works with kernel module ipip

example conf:

file: ipip.netdev

[NetDev]
Name=ipip-tun
Kind=ipip
MTUBytes=1480

[Tunnel]
Local=192.168.223.238
Remote=192.169.224.239
TTL=64

file: ipip.network

[Match]
Name=em1

[Network]
Tunnel=ipip-tun

[tomegun:
         - drop unused variable
         - take ref when enslaving]

2 files changed, 36 insertions, 0 deletions

diff --git a/src/libsystemd-network/network-internal.c b/src/libsystemd-network/network-internal.c
index 52e614c4ea..cf577e54a4 100644
--- a/src/libsystemd-network/network-internal.c
+++ b/src/libsystemd-network/network-internal.c
@@ -326,3 +326,36 @@ int net_parse_inaddr(const char *address, unsigned char *family, void *dst) {
 
         return 0;
 }
+
+int load_module(struct kmod_ctx *ctx, const char *mod_name) {
+        struct kmod_list *modlist = NULL, *l;
+        int r;
+
+        assert(ctx);
+        assert(mod_name);
+
+        r = kmod_module_new_from_lookup(ctx, mod_name, &modlist);
+        if (r < 0)
+                return r;
+
+        if (!modlist) {
+                log_error("Failed to find module '%s'", mod_name);
+                return -ENOENT;
+        }
+
+        kmod_list_foreach(l, modlist) {
+                struct kmod_module *mod = kmod_module_get_module(l);
+
+                r = kmod_module_probe_insert_module(mod, 0, NULL, NULL, NULL, NULL);
+                if (r == 0)
+                        log_info("Inserted module '%s'", kmod_module_get_name(mod));
+                else {
+                        log_error("Failed to insert '%s': %s", kmod_module_get_name(mod),
+                                  strerror(-r));
+                }
+        }
+
+        kmod_module_unref_list(modlist);
+
+        return r;
+}
diff --git a/src/libsystemd-network/network-internal.h b/src/libsystemd-network/network-internal.h
index 836472a776..1c77d33274 100644
--- a/src/libsystemd-network/network-internal.h
+++ b/src/libsystemd-network/network-internal.h
@@ -24,6 +24,7 @@
 #include <netinet/ether.h>
 #include <netinet/in.h>
 #include <stdbool.h>
+#include <libkmod.h>
 
 #include "udev.h"
 #include "condition-util.h"
@@ -65,3 +66,5 @@ int config_parse_ifalias(const char *unit, const char *filename, unsigned line,
 int net_parse_inaddr(const char *address, unsigned char *family, void *dst);
 
 int net_get_unique_predictable_data(struct udev_device *device, uint8_t result[8]);
+
+int load_module(struct kmod_ctx *ctx, const char *mod_name);