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.

11 files changed, 173 insertions, 0 deletions

diff --git a/man/systemd.netdev.xml b/man/systemd.netdev.xml
index 32048054bc..c92792341b 100644
--- a/man/systemd.netdev.xml
+++ b/man/systemd.netdev.xml
@@ -180,6 +180,10 @@
           <row><entry><varname>vcan</varname></entry>
           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 
+          <row><entry><varname>vxcan</varname></entry>
+          <entry>The virtual CAN tunnel driver (vxcan). 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.
+          </entry></row>
+
         </tbody>
       </tgroup>
     </table>
@@ -895,6 +899,22 @@
       </variablelist>
   </refsect1>
   <refsect1>
+  <title>[VXCAN] Section Options</title>
+      <para>The <literal>[VXCAN]</literal> section only applies for
+      netdevs of kind <literal>vxcan</literal> and accepts the
+      following key:</para>
+
+      <variablelist class='network-directives'>
+        <varlistentry>
+          <term><varname>Peer=</varname></term>
+          <listitem>
+            <para>The peer interface name used when creating the netdev.
+            This option is compulsory.</para>
+          </listitem>
+        </varlistentry>
+      </variablelist>
+  </refsect1>
+  <refsect1>
     <title>[Tun] Section Options</title>
 
     <para>The <literal>[Tun]</literal> section only applies for
diff --git a/meson.build b/meson.build
index 6f3f319385..7e997b195a 100644
--- a/meson.build
+++ b/meson.build
@@ -427,6 +427,7 @@ foreach decl : [['IFLA_INET6_ADDR_GEN_MODE',         'linux/if_link.h'],
                 ['IFA_FLAGS',                        'linux/if_addr.h'],
                 ['FRA_UID_RANGE',                    'linux/fib_rules.h'],
                 ['LO_FLAGS_PARTSCAN',                'linux/loop.h'],
+                ['VXCAN_INFO_PEER',                  'linux/can/vxcan.h'],
                ]
         prefix = decl.length() > 2 ? decl[2] : ''
         have = cc.has_header_symbol(decl[1], decl[0], prefix : prefix)
diff --git a/src/basic/missing.h b/src/basic/missing.h
index 3936091ccc..52c7ce57a0 100644
--- a/src/basic/missing.h
+++ b/src/basic/missing.h
@@ -956,6 +956,10 @@ 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/libsystemd/sd-netlink/netlink-types.c b/src/libsystemd/sd-netlink/netlink-types.c
index 9e454702d5..f8be296d37 100644
--- a/src/libsystemd/sd-netlink/netlink-types.c
+++ b/src/libsystemd/sd-netlink/netlink-types.c
@@ -37,6 +37,10 @@
 #include <linux/if_tunnel.h>
 #include <linux/fib_rules.h>
 
+#if HAVE_VXCAN_INFO_PEER
+#include <linux/can/vxcan.h>
+#endif
+
 #include "macro.h"
 #include "missing.h"
 #include "netlink-types.h"
@@ -92,6 +96,10 @@ static const NLType rtnl_link_info_data_veth_types[] = {
         [VETH_INFO_PEER]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
 };
 
+static const NLType rtnl_link_info_data_vxcan_types[] = {
+        [VXCAN_INFO_PEER]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+};
+
 static const NLType rtnl_link_info_data_ipvlan_types[] = {
         [IFLA_IPVLAN_MODE]  = { .type = NETLINK_TYPE_U16 },
 };
@@ -328,6 +336,8 @@ static const char* const nl_union_link_info_data_table[] = {
         [NL_UNION_LINK_INFO_DATA_VRF] = "vrf",
         [NL_UNION_LINK_INFO_DATA_VCAN] = "vcan",
         [NL_UNION_LINK_INFO_DATA_GENEVE] = "geneve",
+        [NL_UNION_LINK_INFO_DATA_VXCAN] = "vxcan",
+
 };
 
 DEFINE_STRING_TABLE_LOOKUP(nl_union_link_info_data, NLUnionLinkInfoData);
@@ -371,6 +381,8 @@ static const NLTypeSystem rtnl_link_info_data_type_systems[] = {
                                                        .types = rtnl_link_info_data_vrf_types },
         [NL_UNION_LINK_INFO_DATA_GENEVE] =           { .count = ELEMENTSOF(rtnl_link_info_data_geneve_types),
                                                        .types = rtnl_link_info_data_geneve_types },
+        [NL_UNION_LINK_INFO_DATA_VXCAN] =            { .count = ELEMENTSOF(rtnl_link_info_data_vxcan_types),
+                                                       .types = rtnl_link_info_data_vxcan_types },
 };
 
 static const NLTypeSystemUnion rtnl_link_info_data_type_system_union = {
diff --git a/src/libsystemd/sd-netlink/netlink-types.h b/src/libsystemd/sd-netlink/netlink-types.h
index ee20edac6f..57b46339f9 100644
--- a/src/libsystemd/sd-netlink/netlink-types.h
+++ b/src/libsystemd/sd-netlink/netlink-types.h
@@ -90,6 +90,7 @@ typedef enum NLUnionLinkInfoData {
         NL_UNION_LINK_INFO_DATA_VRF,
         NL_UNION_LINK_INFO_DATA_VCAN,
         NL_UNION_LINK_INFO_DATA_GENEVE,
+        NL_UNION_LINK_INFO_DATA_VXCAN,
         _NL_UNION_LINK_INFO_DATA_MAX,
         _NL_UNION_LINK_INFO_DATA_INVALID = -1
 } NLUnionLinkInfoData;
diff --git a/src/network/meson.build b/src/network/meson.build
index cc4cbdd996..ed68faca0c 100644
--- a/src/network/meson.build
+++ b/src/network/meson.build
@@ -44,6 +44,8 @@ sources = files('''
         netdev/vxlan.h
         netdev/geneve.c
         netdev/geneve.h
+        netdev/vxcan.c
+        netdev/vxcan.h
         networkd-address-label.c
         networkd-address-label.h
         networkd-address-pool.c
diff --git a/src/network/netdev/netdev-gperf.gperf b/src/network/netdev/netdev-gperf.gperf
index 89f600ef62..628e6648b7 100644
--- a/src/network/netdev/netdev-gperf.gperf
+++ b/src/network/netdev/netdev-gperf.gperf
@@ -17,6 +17,7 @@ _Pragma("GCC diagnostic ignored \"-Wimplicit-fallthrough\"")
 #include "netdev/vxlan.h"
 #include "netdev/vrf.h"
 #include "netdev/netdev.h"
+#include "netdev/vxcan.h"
 #include "vlan-util.h"
 %}
 struct ConfigPerfItem;
@@ -62,6 +63,7 @@ Tunnel.EncapsulationLimit,   config_parse_encap_limit,             0,
 Tunnel.Independent,          config_parse_bool,                    0,                             offsetof(Tunnel, independent)
 Peer.Name,                   config_parse_ifname,                  0,                             offsetof(Veth, ifname_peer)
 Peer.MACAddress,             config_parse_hwaddr,                  0,                             offsetof(Veth, mac_peer)
+VXCAN.Peer,                  config_parse_ifname,                  0,                             offsetof(VxCan, ifname_peer)
 VXLAN.Id,                    config_parse_uint64,                  0,                             offsetof(VxLan, id)
 VXLAN.Group,                 config_parse_vxlan_address,           0,                             offsetof(VxLan, remote)
 VXLAN.Local,                 config_parse_vxlan_address,           0,                             offsetof(VxLan, local)
diff --git a/src/network/netdev/netdev.c b/src/network/netdev/netdev.c
index f148bb43c3..5530760e19 100644
--- a/src/network/netdev/netdev.c
+++ b/src/network/netdev/netdev.c
@@ -48,6 +48,7 @@
 #include "netdev/dummy.h"
 #include "netdev/vrf.h"
 #include "netdev/vcan.h"
+#include "netdev/vxcan.h"
 
 const NetDevVTable * const netdev_vtable[_NETDEV_KIND_MAX] = {
         [NETDEV_KIND_BRIDGE] = &bridge_vtable,
@@ -73,6 +74,7 @@ const NetDevVTable * const netdev_vtable[_NETDEV_KIND_MAX] = {
         [NETDEV_KIND_VRF] = &vrf_vtable,
         [NETDEV_KIND_VCAN] = &vcan_vtable,
         [NETDEV_KIND_GENEVE] = &geneve_vtable,
+        [NETDEV_KIND_VXCAN] = &vxcan_vtable,
 };
 
 static const char* const netdev_kind_table[_NETDEV_KIND_MAX] = {
@@ -99,6 +101,7 @@ static const char* const netdev_kind_table[_NETDEV_KIND_MAX] = {
         [NETDEV_KIND_VRF] = "vrf",
         [NETDEV_KIND_VCAN] = "vcan",
         [NETDEV_KIND_GENEVE] = "geneve",
+        [NETDEV_KIND_VXCAN] = "vxcan",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(netdev_kind, NetDevKind);
diff --git a/src/network/netdev/netdev.h b/src/network/netdev/netdev.h
index 4605308ac4..ec65251464 100644
--- a/src/network/netdev/netdev.h
+++ b/src/network/netdev/netdev.h
@@ -59,6 +59,7 @@ typedef enum NetDevKind {
         NETDEV_KIND_VRF,
         NETDEV_KIND_VCAN,
         NETDEV_KIND_GENEVE,
+        NETDEV_KIND_VXCAN,
         _NETDEV_KIND_MAX,
         _NETDEV_KIND_INVALID = -1
 } NetDevKind;
diff --git a/src/network/netdev/vxcan.c b/src/network/netdev/vxcan.c
new file mode 100644
index 0000000000..a41ca7e256
--- /dev/null
+++ b/src/network/netdev/vxcan.c
@@ -0,0 +1,89 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2017 Susant Sahani
+
+  systemd 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.
+
+  systemd 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 systemd; 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,
+};
diff --git a/src/network/netdev/vxcan.h b/src/network/netdev/vxcan.h
new file mode 100644
index 0000000000..f37213513f
--- /dev/null
+++ b/src/network/netdev/vxcan.h
@@ -0,0 +1,38 @@
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2017 Susant Sahani
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+typedef struct VxCan VxCan;
+
+#if HAVE_VXCAN_INFO_PEER
+#include <linux/can/vxcan.h>
+#endif
+
+#include "netdev/netdev.h"
+
+struct VxCan {
+        NetDev meta;
+
+        char *ifname_peer;
+};
+
+DEFINE_NETDEV_CAST(VXCAN, VxCan);
+
+extern const NetDevVTable vxcan_vtable;