Merge pull request #579 from ssahani/tap-vnet-hdr

networkd: tap add support for vnet_hdr

man/systemd.netdev.xml

@@ -562,6 +562,16 @@
         <literal>no</literal>.</para>
         </listitem>
       </varlistentry>
+      <varlistentry>
+        <term><varname>VnetHeader=</varname></term>
+        <listitem><para>Takes a boolean argument. Configures
+        IFF_VNET_HDR flag for a tap device. It allows sending
+        and receiving larger Generic Segmentation Offload (GSO)
+        packets. This may increase throughput significantly.
+        Defaults to
+        <literal>no</literal>.</para>
+        </listitem>
+      </varlistentry>
       <varlistentry>
         <term><varname>User=</varname></term>
         <listitem><para>User to grant access to the

src/network/networkd-netdev-gperf.gperf

@@ -59,6 +59,7 @@ Tun.Group,                   config_parse_string,                0,
 Tap.OneQueue,                config_parse_bool,                  0,                             offsetof(TunTap, one_queue)
 Tap.MultiQueue,              config_parse_bool,                  0,                             offsetof(TunTap, multi_queue)
 Tap.PacketInfo,              config_parse_bool,                  0,                             offsetof(TunTap, packet_info)
+Tap.VnetHeader,              config_parse_bool,                  0,                             offsetof(TunTap, vnet_hdr)
 Tap.User,                    config_parse_string,                0,                             offsetof(TunTap, user_name)
 Tap.Group,                   config_parse_string,                0,                             offsetof(TunTap, group_name)
 Bond.Mode,                   config_parse_bond_mode,             0,                             offsetof(Bond, mode)

src/network/networkd-netdev-tuntap.c

@@ -51,6 +51,9 @@ static int netdev_fill_tuntap_message(NetDev *netdev, struct ifreq *ifr) {
         if (t->multi_queue)
                 ifr->ifr_flags |= IFF_MULTI_QUEUE;
 
+        if (t->vnet_hdr)
+                ifr->ifr_flags |= IFF_VNET_HDR;
+
         strncpy(ifr->ifr_name, netdev->ifname, IFNAMSIZ-1);
 
         return 0;

src/network/networkd-netdev-tuntap.h

@@ -33,6 +33,7 @@ struct TunTap {
         bool one_queue;
         bool multi_queue;
         bool packet_info;
+        bool vnet_hdr;
 };
 
 extern const NetDevVTable tun_vtable;