openvswitch: upcall: Fix vlan handling.

Networking stack accelerate vlan tag handling by
keeping topmost vlan header in skb. This works as
long as packet remains in OVS datapath. But during
OVS upcall vlan header is pushed on to the packet.
When such packet is sent back to OVS datapath, core
networking stack might not handle it correctly. Following
patch avoids this issue by accelerating the vlan tag
during flow key extract. This simplifies datapath by
bringing uniform packet processing for packets from
all code paths.

Fixes: 5108bbaddc ("openvswitch: add processing of L3 packets").
CC: Jarno Rajahalme <jarno@ovn.org>
CC: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 2d4c4d3911c02ce91de79ac4c9ad4923d4bc2329..9c62b6325f7adc92420b605cf4cdc3b26da437fc 100644 (file)
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -606,7 +606,6 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
        rcu_assign_pointer(flow->sf_acts, acts);
        packet->priority = flow->key.phy.priority;
        packet->mark = flow->key.phy.skb_mark;
-       packet->protocol = flow->key.eth.type;
 
        rcu_read_lock();
        dp = get_dp_rcu(net, ovs_header->dp_ifindex);

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index 08aa926cd5cfe5f6b3f47f3dc4df5c970a6ba2a7..2c0a00f7f1b7d195b98f70e6ec0235b650a63311 100644 (file)
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -312,7 +312,8 @@ static bool icmp6hdr_ok(struct sk_buff *skb)
  * Returns 0 if it encounters a non-vlan or incomplete packet.
  * Returns 1 after successfully parsing vlan tag.
  */
-static int parse_vlan_tag(struct sk_buff *skb, struct vlan_head *key_vh)
+static int parse_vlan_tag(struct sk_buff *skb, struct vlan_head *key_vh,
+                         bool untag_vlan)
 {
        struct vlan_head *vh = (struct vlan_head *)skb->data;
 
@@ -330,7 +331,20 @@ static int parse_vlan_tag(struct sk_buff *skb, struct vlan_head *key_vh)
        key_vh->tci = vh->tci | htons(VLAN_TAG_PRESENT);
        key_vh->tpid = vh->tpid;
 
-       __skb_pull(skb, sizeof(struct vlan_head));
+       if (unlikely(untag_vlan)) {
+               int offset = skb->data - skb_mac_header(skb);
+               u16 tci;
+               int err;
+
+               __skb_push(skb, offset);
+               err = __skb_vlan_pop(skb, &tci);
+               __skb_pull(skb, offset);
+               if (err)
+                       return err;
+               __vlan_hwaccel_put_tag(skb, key_vh->tpid, tci);
+       } else {
+               __skb_pull(skb, sizeof(struct vlan_head));
+       }
        return 1;
 }
 
@@ -351,13 +365,13 @@ static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
                key->eth.vlan.tpid = skb->vlan_proto;
        } else {
                /* Parse outer vlan tag in the non-accelerated case. */
-               res = parse_vlan_tag(skb, &key->eth.vlan);
+               res = parse_vlan_tag(skb, &key->eth.vlan, true);
                if (res <= 0)
                        return res;
        }
 
        /* Parse inner vlan tag. */
-       res = parse_vlan_tag(skb, &key->eth.cvlan);
+       res = parse_vlan_tag(skb, &key->eth.cvlan, false);
        if (res <= 0)
                return res;
 
@@ -800,29 +814,15 @@ int ovs_flow_key_extract_userspace(struct net *net, const struct nlattr *attr,
        if (err)
                return err;
 
-       if (ovs_key_mac_proto(key) == MAC_PROTO_NONE) {
-               /* key_extract assumes that skb->protocol is set-up for
-                * layer 3 packets which is the case for other callers,
-                * in particular packets recieved from the network stack.
-                * Here the correct value can be set from the metadata
-                * extracted above.
-                */
-               skb->protocol = key->eth.type;
-       } else {
-               struct ethhdr *eth;
-
-               skb_reset_mac_header(skb);
-               eth = eth_hdr(skb);
-
-               /* Normally, setting the skb 'protocol' field would be
-                * handled by a call to eth_type_trans(), but it assumes
-                * there's a sending device, which we may not have.
-                */
-               if (eth_proto_is_802_3(eth->h_proto))
-                       skb->protocol = eth->h_proto;
-               else
-                       skb->protocol = htons(ETH_P_802_2);
-       }
+       /* key_extract assumes that skb->protocol is set-up for
+        * layer 3 packets which is the case for other callers,
+        * in particular packets received from the network stack.
+        * Here the correct value can be set from the metadata
+        * extracted above.
+        * For L2 packet key eth type would be zero. skb protocol
+        * would be set to correct value later during key-extact.
+        */
 
+       skb->protocol = key->eth.type;
        return key_extract(skb, key);
 }