networkd: Add support for ERSPAN tunnel

Please see: https://patchwork.ozlabs.org/patch/800327/
```
[NetDev]
Name=erspan-test
Kind=erspan

[Tunnel]
Independent=true
ERSPANIndex=123
Local = 172.16.1.200
Remote = 172.16.1.100
Key=101
SerializeTunneledPackets=true
```

diff --git a/man/systemd.netdev.xml b/man/systemd.netdev.xml
index 3a60b99ee3d9309c78aef36c0f12e899d8b03ba4..42e771f22fdbb46bf4bc8f6fe1668579f1e3c99e 100644 (file)
--- a/man/systemd.netdev.xml
+++ b/man/systemd.netdev.xml
@@ -100,6 +100,11 @@
           <row><entry><varname>gretap</varname></entry>
           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 
+          <row><entry><varname>erspan</varname></entry>
+          <entry>ERSPAN mirrors traffic on one or more source ports and delivers the mirrored traffic to one or more destination ports on another switch.
+          The traffic is encapsulated in generic routing encapsulation (GRE) and is therefore routable across a layer 3 network between the source switch
+          and the destination switch.</entry></row>
+
           <row><entry><varname>ip6gre</varname></entry>
           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 
@@ -919,6 +924,22 @@
           applicable to SIT tunnels.</para>
         </listitem>
       </varlistentry>
+      <varlistentry>
+        <term><varname>SerializeTunneledPackets=</varname></term>
+        <listitem>
+          <para>Takes a boolean value. If set to yes, then packets are serialized. Only applies for ERSPAN tunnel.
+          Defaults to unset.
+          </para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term><varname>ERSPANIndex=</varname></term>
+        <listitem>
+          <para>Specifies the ERSPAN index field for the interface, an integer in the range 1-1048575 associated with
+          the ERSPAN traffic's source port and direction. This field is mandatory.
+          </para>
+        </listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 

diff --git a/meson.build b/meson.build
index 5dc25d03dc7a21407866cee4ae22701d43cfd5bd..8b51d032b814e8776fea54730bf917198762bdd6 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -464,6 +464,7 @@ foreach decl : [['IFLA_INET6_ADDR_GEN_MODE',                'linux/if_link.h'],
                 ['IFLA_VTI_REMOTE',                         'linux/if_tunnel.h', '#include <net/if.h>'],
                 ['IFLA_IPTUN_ENCAP_DPORT',                  'linux/if_tunnel.h', '#include <net/if.h>'],
                 ['IFLA_GRE_ENCAP_DPORT',                    'linux/if_tunnel.h', '#include <net/if.h>'],
+                ['IFLA_GRE_ERSPAN_HWID',                    'linux/if_tunnel.h', '#include <net/if.h>'],
                 ['IFLA_BRIDGE_VLAN_INFO',                   'linux/if_bridge.h'],
                 ['IFLA_BRPORT_PROXYARP',                    'linux/if_link.h'],
                 ['IFLA_BRPORT_LEARNING_SYNC',               'linux/if_link.h'],

diff --git a/src/basic/missing.h b/src/basic/missing.h
index 45788af9e70b4765c2fed5a246f0abc6f804d116..d1003117934bf2d9a6e9abdf98780a18b499a7c1 100644 (file)
--- a/src/basic/missing.h
+++ b/src/basic/missing.h
@@ -877,7 +877,7 @@ struct input_mask {
 #define IFLA_IPTUN_MAX  (__IFLA_IPTUN_MAX - 1)
 #endif
 
-#if !HAVE_IFLA_GRE_ENCAP_DPORT
+#if !HAVE_IFLA_GRE_ERSPAN_HWID
 #define IFLA_GRE_UNSPEC 0
 #define IFLA_GRE_LINK 1
 #define IFLA_GRE_IFLAGS 2
@@ -896,8 +896,14 @@ struct input_mask {
 #define IFLA_GRE_ENCAP_FLAGS 15
 #define IFLA_GRE_ENCAP_SPORT 16
 #define IFLA_GRE_ENCAP_DPORT 17
-
-#define __IFLA_GRE_MAX 18
+#define IFLA_GRE_COLLECT_METADATA 18
+#define IFLA_GRE_IGNORE_DF 19
+#define IFLA_GRE_FWMARK 20
+#define IFLA_GRE_ERSPAN_INDEX 21
+#define IFLA_GRE_ERSPAN_VER 22
+#define IFLA_GRE_ERSPAN_DIR 23
+#define IFLA_GRE_ERSPAN_HWID 24
+#define __IFLA_GRE_MAX 25
 
 #define IFLA_GRE_MAX  (__IFLA_GRE_MAX - 1)
 #endif

diff --git a/src/libsystemd/sd-netlink/netlink-types.c b/src/libsystemd/sd-netlink/netlink-types.c
index 4e42ab175f6e6725edd46791c463916928586a32..307b5aa34349f556f55ad7e9aaaf58cd7f89e6a0 100644 (file)
--- a/src/libsystemd/sd-netlink/netlink-types.c
+++ b/src/libsystemd/sd-netlink/netlink-types.c
@@ -265,6 +265,7 @@ static  const NLType rtnl_link_info_data_ipgre_types[] = {
         [IFLA_GRE_ENCAP_FLAGS]  = { .type = NETLINK_TYPE_U16 },
         [IFLA_GRE_ENCAP_SPORT]  = { .type = NETLINK_TYPE_U16 },
         [IFLA_GRE_ENCAP_DPORT]  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_ERSPAN_INDEX] = { .type = NETLINK_TYPE_U32 },
 };
 
 static const NLType rtnl_link_info_data_ipvti_types[] = {
@@ -321,6 +322,7 @@ static const char* const nl_union_link_info_data_table[] = {
         [NL_UNION_LINK_INFO_DATA_VXLAN] = "vxlan",
         [NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL] = "ipip",
         [NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL] = "gre",
+        [NL_UNION_LINK_INFO_DATA_ERSPAN] = "erspan",
         [NL_UNION_LINK_INFO_DATA_IPGRETAP_TUNNEL] = "gretap",
         [NL_UNION_LINK_INFO_DATA_IP6GRE_TUNNEL] = "ip6gre",
         [NL_UNION_LINK_INFO_DATA_IP6GRETAP_TUNNEL] = "ip6gretap",
@@ -360,6 +362,8 @@ static const NLTypeSystem rtnl_link_info_data_type_systems[] = {
                                                        .types = rtnl_link_info_data_iptun_types },
         [NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL] =     { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
                                                        .types = rtnl_link_info_data_ipgre_types },
+        [NL_UNION_LINK_INFO_DATA_ERSPAN] =           { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
+                                                       .types = rtnl_link_info_data_ipgre_types },
         [NL_UNION_LINK_INFO_DATA_IPGRETAP_TUNNEL] =  { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
                                                        .types = rtnl_link_info_data_ipgre_types },
         [NL_UNION_LINK_INFO_DATA_IP6GRE_TUNNEL] =    { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),

diff --git a/src/libsystemd/sd-netlink/netlink-types.h b/src/libsystemd/sd-netlink/netlink-types.h
index e8443aacd6d852a75dd83c3d8581dee08b393aa2..3133e4863d1e2a2b862fcb44077c128318fc1c78 100644 (file)
--- a/src/libsystemd/sd-netlink/netlink-types.h
+++ b/src/libsystemd/sd-netlink/netlink-types.h
@@ -64,6 +64,7 @@ typedef enum NLUnionLinkInfoData {
         NL_UNION_LINK_INFO_DATA_VXLAN,
         NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL,
         NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_ERSPAN,
         NL_UNION_LINK_INFO_DATA_IPGRETAP_TUNNEL,
         NL_UNION_LINK_INFO_DATA_IP6GRE_TUNNEL,
         NL_UNION_LINK_INFO_DATA_IP6GRETAP_TUNNEL,

diff --git a/src/network/netdev/netdev-gperf.gperf b/src/network/netdev/netdev-gperf.gperf
index be7f004d632ff5214384d8717c9057ca3baf8e13..49752c2d8a2e96bcd57dc61573c37b08aee636ae 100644 (file)
--- a/src/network/netdev/netdev-gperf.gperf
+++ b/src/network/netdev/netdev-gperf.gperf
@@ -71,6 +71,8 @@ Tunnel.FOUDestinationPort,         config_parse_ip_port,                 0,
 Tunnel.FOUSourcePort,              config_parse_ip_port,                 0,                             offsetof(Tunnel, encap_src_port)
 Tunnel.Encapsulation,              config_parse_fou_encap_type,          0,                             offsetof(Tunnel, fou_encap_type)
 Tunnel.IPv6RapidDeploymentPrefix,  config_parse_6rd_prefix,              0,                             0
+Tunnel.ERSPANIndex,                config_parse_uint32,                  0,                             offsetof(Tunnel, erspan_index)
+Tunnel.SerializeTunneledPackets,   config_parse_tristate,                0,                             offsetof(Tunnel, erspan_sequence)
 FooOverUDP.Protocol,               config_parse_uint8,                   0,                             offsetof(FouTunnel, fou_protocol)
 FooOverUDP.Encapsulation,          config_parse_fou_encap_type,          0,                             offsetof(FouTunnel, fou_encap_type)
 FooOverUDP.Port,                   config_parse_ip_port,                 0,                             offsetof(FouTunnel, port)

diff --git a/src/network/netdev/netdev.c b/src/network/netdev/netdev.c
index 4a07fb5d377f7988a7c9a59432678b939b455da9..c3cebe450cb456ab0fef8eddba32a51ddb02e00c 100644 (file)
--- a/src/network/netdev/netdev.c
+++ b/src/network/netdev/netdev.c
@@ -64,6 +64,7 @@ const NetDevVTable * const netdev_vtable[_NETDEV_KIND_MAX] = {
         [NETDEV_KIND_WIREGUARD] = &wireguard_vtable,
         [NETDEV_KIND_NETDEVSIM] = &netdevsim_vtable,
         [NETDEV_KIND_FOU] = &foutnl_vtable,
+        [NETDEV_KIND_ERSPAN] = &erspan_vtable,
 };
 
 static const char* const netdev_kind_table[_NETDEV_KIND_MAX] = {
@@ -94,6 +95,7 @@ static const char* const netdev_kind_table[_NETDEV_KIND_MAX] = {
         [NETDEV_KIND_WIREGUARD] = "wireguard",
         [NETDEV_KIND_NETDEVSIM] = "netdevsim",
         [NETDEV_KIND_FOU] = "fou",
+        [NETDEV_KIND_ERSPAN] = "erspan",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(netdev_kind, NetDevKind);

diff --git a/src/network/netdev/netdev.h b/src/network/netdev/netdev.h
index 6597897d2f4812f951639675e4c1f1aa9b5db980..8c84a43971f60c785a9da30d331929b575cc31f5 100644 (file)
--- a/src/network/netdev/netdev.h
+++ b/src/network/netdev/netdev.h
@@ -45,6 +45,7 @@ typedef enum NetDevKind {
         NETDEV_KIND_WIREGUARD,
         NETDEV_KIND_NETDEVSIM,
         NETDEV_KIND_FOU,
+        NETDEV_KIND_ERSPAN,
         _NETDEV_KIND_MAX,
         _NETDEV_KIND_INVALID = -1
 } NetDevKind;

diff --git a/src/network/netdev/tunnel.c b/src/network/netdev/tunnel.c
index fa9a9ac077b46628c26f463a3f4339abac8c6856..36f1fe7b03403c959d23422f9727b66010b7a704 100644 (file)
--- a/src/network/netdev/tunnel.c
+++ b/src/network/netdev/tunnel.c
@@ -173,6 +173,77 @@ static int netdev_gre_fill_message_create(NetDev *netdev, Link *link, sd_netlink
         return r;
 }
 
+static int netdev_erspan_fill_message_create(NetDev *netdev, Link *link, sd_netlink_message *m) {
+        uint32_t ikey = 0;
+        uint32_t okey = 0;
+        uint16_t iflags = 0;
+        uint16_t oflags = 0;
+        Tunnel *t;
+        int r;
+
+        assert(netdev);
+
+        t = ERSPAN(netdev);
+
+        assert(t);
+        assert(IN_SET(t->family, AF_INET, AF_UNSPEC));
+        assert(m);
+
+        r = sd_netlink_message_append_u32(m, IFLA_GRE_ERSPAN_INDEX, t->erspan_index);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_ERSPAN_INDEX attribute: %m");
+
+        if (t->key != 0) {
+                ikey = okey = htobe32(t->key);
+                iflags |= GRE_KEY;
+                oflags |= GRE_KEY;
+        }
+
+        if (t->ikey != 0) {
+                ikey = htobe32(t->ikey);
+                iflags |= GRE_KEY;
+        }
+
+        if (t->okey != 0) {
+                okey = htobe32(t->okey);
+                oflags |= GRE_KEY;
+        }
+
+        if (t->erspan_sequence > 0) {
+                iflags |= GRE_SEQ;
+                oflags |= GRE_SEQ;
+        } else if (t->erspan_sequence == 0) {
+                iflags &= ~GRE_SEQ;
+                oflags &= ~GRE_SEQ;
+        }
+
+        r = sd_netlink_message_append_u32(m, IFLA_GRE_IKEY, ikey);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_IKEY attribute: %m");
+
+        r = sd_netlink_message_append_u32(m, IFLA_GRE_OKEY, okey);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_OKEY attribute: %m");
+
+        r = sd_netlink_message_append_u16(m, IFLA_GRE_IFLAGS, iflags);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_IFLAGS attribute: %m");
+
+        r = sd_netlink_message_append_u16(m, IFLA_GRE_OFLAGS, oflags);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_OFLAGS, attribute: %m");
+
+        r = sd_netlink_message_append_in_addr(m, IFLA_GRE_LOCAL, &t->local.in);
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_LOCAL attribute: %m");
+
+        r = sd_netlink_message_append_in_addr(m, IFLA_GRE_REMOTE, &t->remote.in);
+        if (r < 0)
+                log_netdev_error_errno(netdev, r, "Could not append IFLA_GRE_REMOTE attribute: %m");
+
+        return r;
+}
+
 static int netdev_ip6gre_fill_message_create(NetDev *netdev, Link *link, sd_netlink_message *m) {
         Tunnel *t;
         int r;
@@ -415,6 +486,9 @@ static int netdev_tunnel_verify(NetDev *netdev, const char *filename) {
         case NETDEV_KIND_IP6TNL:
                 t = IP6TNL(netdev);
                 break;
+        case NETDEV_KIND_ERSPAN:
+                t = ERSPAN(netdev);
+                break;
         default:
                 assert_not_reached("Invalid tunnel kind");
         }
@@ -427,10 +501,10 @@ static int netdev_tunnel_verify(NetDev *netdev, const char *filename) {
                 return -EINVAL;
         }
 
-        if (IN_SET(netdev->kind, NETDEV_KIND_VTI, NETDEV_KIND_IPIP, NETDEV_KIND_SIT, NETDEV_KIND_GRE, NETDEV_KIND_GRETAP) &&
+        if (IN_SET(netdev->kind, NETDEV_KIND_VTI, NETDEV_KIND_IPIP, NETDEV_KIND_SIT, NETDEV_KIND_GRE, NETDEV_KIND_GRETAP, NETDEV_KIND_ERSPAN) &&
             (t->family != AF_INET || in_addr_is_null(t->family, &t->local))) {
                 log_netdev_error(netdev,
-                                 "vti/ipip/sit/gre/gretap tunnel without a local IPv4 address configured in %s. Ignoring", filename);
+                                 "vti/ipip/sit/gre/gretap/erspan tunnel without a local IPv4 address configured in %s. Ignoring", filename);
                 return -EINVAL;
         }
 
@@ -453,6 +527,11 @@ static int netdev_tunnel_verify(NetDev *netdev, const char *filename) {
                 return -EINVAL;
         }
 
+        if (netdev->kind == NETDEV_KIND_ERSPAN && (t->erspan_index >= (1 << 20) || t->erspan_index == 0)) {
+                log_netdev_error(netdev, "Invalid erspan index %d. Ignoring", t->erspan_index);
+                return -EINVAL;
+        }
+
         return 0;
 }
 
@@ -729,6 +808,18 @@ static void ip6gre_init(NetDev *n) {
         t->ttl = DEFAULT_TNL_HOP_LIMIT;
 }
 
+static void erspan_init(NetDev *n) {
+        Tunnel *t;
+
+        assert(n);
+
+        t = ERSPAN(n);
+
+        assert(t);
+
+        t->erspan_sequence = -1;
+}
+
 static void ip6tnl_init(NetDev *n) {
         Tunnel *t = IP6TNL(n);
 
@@ -822,3 +913,12 @@ const NetDevVTable ip6tnl_vtable = {
         .create_type = NETDEV_CREATE_STACKED,
         .config_verify = netdev_tunnel_verify,
 };
+
+const NetDevVTable erspan_vtable = {
+        .object_size = sizeof(Tunnel),
+        .init = erspan_init,
+        .sections = "Match\0NetDev\0Tunnel\0",
+        .fill_message_create = netdev_erspan_fill_message_create,
+        .create_type = NETDEV_CREATE_INDEPENDENT,
+        .config_verify = netdev_tunnel_verify,
+};

diff --git a/src/network/netdev/tunnel.h b/src/network/netdev/tunnel.h
index be73c513cc6bfee2c684356d3bdd6126cd45c466..51b61637ad44a92fcf25ed848f7e583d3826a022 100644 (file)
--- a/src/network/netdev/tunnel.h
+++ b/src/network/netdev/tunnel.h
@@ -29,6 +29,7 @@ typedef struct Tunnel {
         int family;
         int ipv6_flowlabel;
         int allow_localremote;
+        int erspan_sequence;
 
         unsigned ttl;
         unsigned tos;
@@ -37,6 +38,7 @@ typedef struct Tunnel {
         uint32_t key;
         uint32_t ikey;
         uint32_t okey;
+        uint32_t erspan_index;
 
         union in_addr_union local;
         union in_addr_union remote;
@@ -65,6 +67,7 @@ DEFINE_NETDEV_CAST(SIT, Tunnel);
 DEFINE_NETDEV_CAST(VTI, Tunnel);
 DEFINE_NETDEV_CAST(VTI6, Tunnel);
 DEFINE_NETDEV_CAST(IP6TNL, Tunnel);
+DEFINE_NETDEV_CAST(ERSPAN, Tunnel);
 extern const NetDevVTable ipip_vtable;
 extern const NetDevVTable sit_vtable;
 extern const NetDevVTable vti_vtable;
@@ -74,6 +77,7 @@ extern const NetDevVTable gretap_vtable;
 extern const NetDevVTable ip6gre_vtable;
 extern const NetDevVTable ip6gretap_vtable;
 extern const NetDevVTable ip6tnl_vtable;
+extern const NetDevVTable erspan_vtable;
 
 const char *ip6tnl_mode_to_string(Ip6TnlMode d) _const_;
 Ip6TnlMode ip6tnl_mode_from_string(const char *d) _pure_;

diff --git a/test/test-network/conf/25-erspan-tunnel.netdev b/test/test-network/conf/25-erspan-tunnel.netdev
new file mode 100644 (file)
index 0000000..746b7ac
--- /dev/null
+++ b/test/test-network/conf/25-erspan-tunnel.netdev
@@ -0,0 +1,11 @@
+[NetDev]
+Name=erspan-test
+Kind=erspan
+
+[Tunnel]
+Independent=true
+ERSPANIndex=123
+Local = 172.16.1.200
+Remote = 172.16.1.100
+Key=101
+SerializeTunneledPackets=true

diff --git a/test/test-network/systemd-networkd-tests.py b/test/test-network/systemd-networkd-tests.py
index 48640068b6dbfab226b279d6e383f0f0ea57a586..73ecf6f73f869cd1404e49c613082809d1efe84b 100755 (executable)
--- a/test/test-network/systemd-networkd-tests.py
+++ b/test/test-network/systemd-networkd-tests.py
@@ -153,17 +153,18 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
     links =['bridge99', 'bond99', 'bond99', 'vlan99', 'test1', 'macvtap99',
             'macvlan99', 'ipvlan99', 'vxlan99', 'veth99', 'vrf99', 'tun99',
             'tap99', 'vcan99', 'geneve99', 'dummy98', 'ipiptun99', 'sittun99', '6rdtun99',
-            'gretap99', 'vtitun99', 'vti6tun99','ip6tnl99', 'gretun99', 'ip6gretap99', 'wg99', 'dropin-test']
+            'gretap99', 'vtitun99', 'vti6tun99','ip6tnl99', 'gretun99', 'ip6gretap99',
+            'wg99', 'dropin-test', 'erspan-test']
 
     units = ['25-bridge.netdev', '25-bond.netdev', '21-vlan.netdev', '11-dummy.netdev', '21-vlan.network',
              '21-macvtap.netdev', 'macvtap.network', '21-macvlan.netdev', 'macvlan.network', 'vxlan.network',
              '25-vxlan.netdev', '25-ipvlan.netdev', 'ipvlan.network', '25-veth.netdev', '25-vrf.netdev',
              '25-tun.netdev', '25-tun.netdev', '25-vcan.netdev', '25-geneve.netdev', '25-ipip-tunnel.netdev',
-             '25-ip6tnl-tunnel.netdev', '25-ip6gre-tunnel.netdev','25-sit-tunnel.netdev', '25-6rd-tunnel.netdev',
-             '25-gre-tunnel.netdev', '25-gretap-tunnel.netdev', '25-vti-tunnel.netdev', '25-vti6-tunnel.netdev',
-             '12-dummy.netdev', 'gre.network', 'ipip.network', 'ip6gretap.network', 'gretun.network',
-             'ip6tnl.network', '25-tap.netdev', 'vti6.network', 'vti.network', 'gretap.network', 'sit.network',
-             '25-ipip-tunnel-independent.netdev', '25-wireguard.netdev', '6rd.network', '10-dropin-test.netdev']
+             '25-ip6tnl-tunnel.netdev', '25-ip6gre-tunnel.netdev', '25-sit-tunnel.netdev', '25-6rd-tunnel.netdev',
+             '25-erspan-tunnel.netdev', '25-gre-tunnel.netdev', '25-gretap-tunnel.netdev', '25-vti-tunnel.netdev',
+             '25-vti6-tunnel.netdev', '12-dummy.netdev', 'gre.network', 'ipip.network', 'ip6gretap.network',
+             'gretun.network', 'ip6tnl.network', '25-tap.netdev', 'vti6.network', 'vti.network', 'gretap.network',
+             'sit.network', '25-ipip-tunnel-independent.netdev', '25-wireguard.netdev', '6rd.network', '10-dropin-test.netdev']
 
     def setUp(self):
         self.link_remove(self.links)
@@ -383,6 +384,18 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
         self.assertTrue(self.link_exits('dummy98'))
         self.assertTrue(self.link_exits('sittun99'))
 
+    def test_erspan_tunnel(self):
+        self.copy_unit_to_networkd_unit_path('25-erspan-tunnel.netdev')
+        self.start_networkd()
+
+        self.assertTrue(self.link_exits('erspan-test'))
+
+        output = subprocess.check_output(['ip', '-d', 'link', 'show', 'erspan-test']).rstrip().decode('utf-8')
+        print(output)
+        self.assertTrue(output, '172.16.1.200')
+        self.assertTrue(output, '172.16.1.100')
+        self.assertTrue(output, '101')
+
     def test_tunnel_independent(self):
         self.copy_unit_to_networkd_unit_path('25-ipip-tunnel-independent.netdev')