networkd: introduce vxcan netdev. (#7150)

Similar to the virtual ethernet driver veth, vxcan implements a
local CAN traffic tunnel between two virtual CAN network devices.
When creating a vxcan, two vxcan devices are created as pair
When one end receives the packet it appears on its pair and vice
versa. The vxcan can be used for cross namespace communication.

2 files changed, 93 insertions, 0 deletions

diff --git a/src/basic/missing.h b/src/basic/missing.h
index 63eacbb17..4830a9723 100644
--- a/src/basic/missing.h
+++ b/src/basic/missing.h
@@ -960,6 +960,10 @@ struct input_mask {
 #define IFLA_VRF_TABLE 1
 #endif
 
+#if !HAVE_VXCAN_INFO_PEER
+#define VXCAN_INFO_PEER 1
+#endif
+
 #if !HAVE_NDA_IFINDEX
 #define NDA_UNSPEC 0
 #define NDA_DST 1
diff --git a/src/network/netdev/vxcan.c b/src/network/netdev/vxcan.c
new file mode 100644
index 000000000..e8a71d645
--- /dev/null
+++ b/src/network/netdev/vxcan.c
@@ -0,0 +1,89 @@
+/***
+  This file is part of elogind.
+
+  Copyright 2017 Susant Sahani
+
+  elogind is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  elogind is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with elogind; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "netdev/vxcan.h"
+#include "missing.h"
+
+static int netdev_vxcan_fill_message_create(NetDev *netdev, Link *link, sd_netlink_message *m) {
+        VxCan *v;
+        int r;
+
+        assert(netdev);
+        assert(!link);
+        assert(m);
+
+        v = VXCAN(netdev);
+
+        assert(v);
+
+        r = sd_netlink_message_open_container(m, VXCAN_INFO_PEER);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append VXCAN_INFO_PEER attribute: %m");
+
+        if (v->ifname_peer) {
+                r = sd_netlink_message_append_string(m, IFLA_IFNAME, v->ifname_peer);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to add vxcan netlink interface peer name: %m");
+        }
+
+        r = sd_netlink_message_close_container(m);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append VXCAN_INFO_PEER attribute: %m");
+
+        return r;
+}
+
+static int netdev_vxcan_verify(NetDev *netdev, const char *filename) {
+        VxCan *v;
+
+        assert(netdev);
+        assert(filename);
+
+        v = VXCAN(netdev);
+
+        assert(v);
+
+        if (!v->ifname_peer) {
+                log_warning("VxCan NetDev without peer name configured in %s. Ignoring", filename);
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static void vxcan_done(NetDev *n) {
+        VxCan *v;
+
+        assert(n);
+
+        v = VXCAN(n);
+
+        assert(v);
+
+        free(v->ifname_peer);
+}
+
+const NetDevVTable vxcan_vtable = {
+        .object_size = sizeof(VxCan),
+        .sections = "Match\0NetDev\0VXCAN\0",
+        .done = vxcan_done,
+        .fill_message_create = netdev_vxcan_fill_message_create,
+        .create_type = NETDEV_CREATE_INDEPENDENT,
+        .config_verify = netdev_vxcan_verify,
+};