Merge pull request #11021 from ssahani/isatap

networkd: Add support to configure ISATAP tunnel

src/network/netdev/netdev-gperf.gperf

@@ -73,6 +73,7 @@ Tunnel.Encapsulation,              config_parse_fou_encap_type,          0,
 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)
+Tunnel.ISATAP,                     config_parse_tristate,                0,                             offsetof(Tunnel, isatap)
 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)

src/network/netdev/tunnel.c

@@ -118,6 +118,7 @@ static int netdev_sit_fill_message_create(NetDev *netdev, Link *link, sd_netlink
                 r = sd_netlink_message_append_in6_addr(m, IFLA_IPTUN_6RD_PREFIX, &t->sixrd_prefix);
                 if (r < 0)
                         return log_netdev_error_errno(netdev, r, "Could not append IFLA_IPTUN_6RD_PREFIX attribute: %m");
+
                 /* u16 is deliberate here, even though we're passing a netmask that can never be >128. The kernel is
                  * expecting to receive the prefixlen as a u16.
                  */
@@ -126,6 +127,16 @@ static int netdev_sit_fill_message_create(NetDev *netdev, Link *link, sd_netlink
                         return log_netdev_error_errno(netdev, r, "Could not append IFLA_IPTUN_6RD_PREFIXLEN attribute: %m");
         }
 
+        if (t->isatap >= 0) {
+                uint16_t flags = 0;
+
+                SET_FLAG(flags, SIT_ISATAP, t->isatap);
+
+                r = sd_netlink_message_append_u16(m, IFLA_IPTUN_FLAGS, flags);
+                if (r < 0)
+                        return log_netdev_error_errno(netdev, r, "Could not append IFLA_IPTUN_FLAGS attribute: %m");
+        }
+
         return r;
 }
 
@@ -761,6 +772,7 @@ static void sit_init(NetDev *n) {
         assert(t);
 
         t->pmtudisc = true;
+        t->isatap = -1;
 }
 
 static void vti_init(NetDev *n) {

src/network/netdev/tunnel.h

@@ -30,6 +30,7 @@ typedef struct Tunnel {
         int ipv6_flowlabel;
         int allow_localremote;
         int erspan_sequence;
+        int isatap;
 
         unsigned ttl;
         unsigned tos;