datapath: VLAN actions should use push/pop semantics

Currently the kernel vlan actions mirror those used by OpenFlow 1.0.
i.e. MODIFY and STRIP. More flexible approach is to have an action to
push a tag and pop a tag off, so that it can handle multiple levels of vlan
tags. Plus it aligns with newer version of OpenFlow.
        As this patch replaces MODIFY with PUSH semantic, action
mapping done in userpace is fixed accordingly.
        GSO handling for multiple levels of vlan tags is also added as
Jesse suggested before.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

1 files changed, 14 insertions, 20 deletions

diff --git a/lib/packets.c b/lib/packets.c
index e05e3ebc..094f5536 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -75,33 +75,27 @@ compose_benign_packet(struct ofpbuf *b, const char *tag, uint16_t snap_type,
     memcpy(payload + tag_size, eth_src, ETH_ADDR_LEN);
 }
 
-/* Modify the TCI field of 'packet', whose data must begin with an Ethernet
- * header.  If a VLAN tag is present, its TCI field is replaced by 'tci'.  If a
- * VLAN tag is not present, one is added with the TCI field set to 'tci'.
+/* Insert VLAN header according to given TCI. Packet passed must be Ethernet
+ * packet.
  *
  * Also sets 'packet->l2' to point to the new Ethernet header. */
 void
-eth_set_vlan_tci(struct ofpbuf *packet, ovs_be16 tci)
+eth_push_vlan(struct ofpbuf *packet, ovs_be16 tci)
 {
     struct eth_header *eh = packet->data;
     struct vlan_eth_header *veh;
 
-    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);
-    }
+    /* 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;
 }