- /* Compose LLC, SNAP headers. */
- llc_snap->llc.llc_dsap = LLC_DSAP_SNAP;
- llc_snap->llc.llc_ssap = LLC_SSAP_SNAP;
- llc_snap->llc.llc_cntl = LLC_CNTL_SNAP;
- memcpy(llc_snap->snap.snap_org, "\x00\x23\x20", 3);
- llc_snap->snap.snap_type = htons(snap_type);
+ if (packet->size >= sizeof(struct vlan_eth_header)
+ && eh->eth_type == htons(ETH_TYPE_VLAN)) {
+ veh = packet->data;
+ veh->veth_tci = tci;
+ } else {
+ /* Insert new 802.1Q header. */
+ struct vlan_eth_header tmp;
+ memcpy(tmp.veth_dst, eh->eth_dst, ETH_ADDR_LEN);
+ memcpy(tmp.veth_src, eh->eth_src, ETH_ADDR_LEN);
+ tmp.veth_type = htons(ETH_TYPE_VLAN);
+ tmp.veth_tci = tci;
+ tmp.veth_next_type = eh->eth_type;
+
+ veh = ofpbuf_push_uninit(packet, VLAN_HEADER_LEN);
+ memcpy(veh, &tmp, sizeof tmp);
+ }
+ packet->l2 = packet->data;