networkd: introduce gre tunnel

This patch enables gre tunnel support.

example conf:

file : gre.netdev
[NetDev]
Name=gre-tun
Kind=gre
MTUBytes=1480

[Tunnel]
Local=X.X.X.X
Remote=X.X.X.X

file: gre.network
[Match]
Name=em1

[Network]
Tunnel=gre-tun

TODO:

Add more attributes for gre tunnel
IFLA_GRE_IFLAGS
IFLA_GRE_IFLAGS
IFLA_GRE_IKEY
IFLA_GRE_OKEY

2 files changed, 127 insertions, 0 deletions

diff --git a/src/libsystemd/sd-rtnl/rtnl-types.c b/src/libsystemd/sd-rtnl/rtnl-types.c
index 96467a32a..d32855d94 100644
--- a/src/libsystemd/sd-rtnl/rtnl-types.c
+++ b/src/libsystemd/sd-rtnl/rtnl-types.c
@@ -117,6 +117,19 @@ static const NLType rtnl_link_info_data_iptun_types[IFLA_IPTUN_MAX + 1] = {
         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
 };
 
+static  const NLType rtnl_link_info_data_ipgre_types[IFLA_GRE_MAX + 1] = {
+        [IFLA_GRE_LINK]     = { .type = NLA_U32 },
+        [IFLA_GRE_IFLAGS]   = { .type = NLA_U16 },
+        [IFLA_GRE_OFLAGS]   = { .type = NLA_U16 },
+        [IFLA_GRE_IKEY]     = { .type = NLA_U32 },
+        [IFLA_GRE_OKEY]     = { .type = NLA_U32 },
+        [IFLA_GRE_LOCAL]    = { .type = NLA_IN_ADDR },
+        [IFLA_GRE_REMOTE]   = { .type = NLA_IN_ADDR },
+        [IFLA_GRE_TTL]      = { .type = NLA_U8 },
+        [IFLA_GRE_TOS]      = { .type = NLA_U8 },
+        [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
+};
+
 typedef enum NLUnionLinkInfoData {
         NL_UNION_LINK_INFO_DATA_BOND,
         NL_UNION_LINK_INFO_DATA_BRIDGE,
@@ -124,6 +137,7 @@ typedef enum NLUnionLinkInfoData {
         NL_UNION_LINK_INFO_DATA_VETH,
         NL_UNION_LINK_INFO_DATA_MACVLAN,
         NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL,
         NL_UNION_LINK_INFO_DATA_SIT_TUNNEL,
         _NL_UNION_LINK_INFO_DATA_MAX,
         _NL_UNION_LINK_INFO_DATA_INVALID = -1
@@ -140,6 +154,7 @@ static const char* const nl_union_link_info_data_table[_NL_UNION_LINK_INFO_DATA_
         [NL_UNION_LINK_INFO_DATA_VETH] = "veth",
         [NL_UNION_LINK_INFO_DATA_MACVLAN] = "macvlan",
         [NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL] = "ipip",
+        [NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL] = "gre",
         [NL_UNION_LINK_INFO_DATA_SIT_TUNNEL] = "sit",
 };
 
@@ -158,6 +173,8 @@ static const NLTypeSystem rtnl_link_info_data_type_systems[_NL_UNION_LINK_INFO_D
                                                   .types = rtnl_link_info_data_macvlan_types },
         [NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL] = { .max = ELEMENTSOF(rtnl_link_info_data_iptun_types) - 1,
                                                   .types = rtnl_link_info_data_iptun_types },
+        [NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL] =  { .max = ELEMENTSOF(rtnl_link_info_data_ipgre_types) - 1,
+                                                    .types = rtnl_link_info_data_ipgre_types },
         [NL_UNION_LINK_INFO_DATA_SIT_TUNNEL] =  { .max = ELEMENTSOF(rtnl_link_info_data_iptun_types) - 1,
                                                   .types = rtnl_link_info_data_iptun_types },
 };
diff --git a/src/network/networkd-tunnel.c b/src/network/networkd-tunnel.c
index fee474cf4..9b4cb4f95 100644
--- a/src/network/networkd-tunnel.c
+++ b/src/network/networkd-tunnel.c
@@ -226,6 +226,112 @@ static int netdev_fill_sit_rtnl_message(Link *link, sd_rtnl_message *m) {
         return r;
 }
 
+static int netdev_fill_ipgre_rtnl_message(Link *link, sd_rtnl_message *m) {
+        NetDev *netdev;
+        int r;
+
+        assert(link);
+        assert(link->network);
+        assert(link->network->tunnel);
+        assert(m);
+
+        netdev = link->network->tunnel;
+
+        r = sd_rtnl_message_append_string(m, IFLA_IFNAME, netdev->ifname);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_IFNAME, attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        if(netdev->mtu) {
+                r = sd_rtnl_message_append_u32(m, IFLA_MTU, netdev->mtu);
+                if (r < 0) {
+                        log_error_netdev(netdev,
+                                         "Could not append IFLA_MTU attribute: %s",
+                                         strerror(-r));
+                        return r;
+                }
+        }
+
+        r = sd_rtnl_message_open_container(m, IFLA_LINKINFO);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_LINKINFO attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_open_container_union(m, IFLA_INFO_DATA,
+                                                 netdev_kind_to_string(netdev->kind));
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_INFO_DATA attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append_u32(m, IFLA_GRE_LINK, link->ifindex);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_GRE_LINK attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append_in_addr(m, IFLA_GRE_LOCAL, &netdev->tunnel_local);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_GRE_LOCAL attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append_in_addr(m, IFLA_GRE_REMOTE, &netdev->tunnel_remote);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_GRE_REMOTE attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append_u8(m, IFLA_GRE_TTL, netdev->tunnel_ttl);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_GRE_TTL attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_append_u8(m, IFLA_GRE_TOS, netdev->tunnel_tos);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_GRE_TOS attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_close_container(m);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_INFO_DATA attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        r = sd_rtnl_message_close_container(m);
+        if (r < 0) {
+                log_error_netdev(netdev,
+                                 "Could not append IFLA_LINKINFO attribute: %s",
+                                 strerror(-r));
+                return r;
+        }
+
+        return r;
+}
+
+
 int netdev_create_tunnel(Link *link, sd_rtnl_message_handler_t callback) {
         _cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
         NetDev *netdev;
@@ -281,6 +387,10 @@ int netdev_create_tunnel(Link *link, sd_rtnl_message_handler_t callback) {
                         return r;
                 break;
         case NETDEV_KIND_GRE:
+                r = netdev_fill_ipgre_rtnl_message(link, m);
+                if(r < 0)
+                        return r;
+                break;
         default:
                 return -ENOTSUP;
         }