From ed246cee09b9865145a2e1e34f63ec0e31dd83a5 Mon Sep 17 00:00:00 2001
From: John Hurley <john.hurley@netronome.com>
Date: Sun, 7 Jul 2019 15:01:55 +0100
Subject: [PATCH] net: core: move pop MPLS functionality from OvS to core
helper
Open vSwitch provides code to pop an MPLS header to a packet. In
preparation for supporting this in TC, move the pop code to an skb helper
that can be reused.
Remove the, now unused, update_ethertype static function from OvS.
Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/skbuff.h | 1 +
net/core/skbuff.c | 42 +++++++++++++++++++++++++++++++++++++++
net/openvswitch/actions.c | 37 ++--------------------------------
3 files changed, 45 insertions(+), 35 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 1dc55000710c2d..08d1c8e705405e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3448,6 +3448,7 @@ int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
int skb_vlan_pop(struct sk_buff *skb);
int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto);
+int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto);
struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
gfp_t gfp);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 495fd743a93589..8c00be4d891942 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5489,6 +5489,48 @@ int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto)
}
EXPORT_SYMBOL_GPL(skb_mpls_push);
+/**
+ * skb_mpls_pop() - pop the outermost MPLS header
+ *
+ * @skb: buffer
+ * @next_proto: ethertype of header after popped MPLS header
+ *
+ * Expects skb->data at mac header.
+ *
+ * Returns 0 on success, -errno otherwise.
+ */
+int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)
+{
+ int err;
+
+ if (unlikely(!eth_p_mpls(skb->protocol)))
+ return -EINVAL;
+
+ err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
+ if (unlikely(err))
+ return err;
+
+ skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
+ memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
+ skb->mac_len);
+
+ __skb_pull(skb, MPLS_HLEN);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, skb->mac_len);
+
+ if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
+ struct ethhdr *hdr;
+
+ /* use mpls_hdr() to get ethertype to account for VLANs. */
+ hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
+ skb_mod_eth_type(skb, hdr, next_proto);
+ }
+ skb->protocol = next_proto;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_mpls_pop);
+
/**
* alloc_skb_with_frags - allocate skb with page frags
*
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index a9a6c9cbf946d0..62715bb8d6110b 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -160,18 +160,6 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key,
const struct nlattr *attr, int len);
-static void update_ethertype(struct sk_buff *skb, struct ethhdr *hdr,
- __be16 ethertype)
-{
- if (skb->ip_summed == CHECKSUM_COMPLETE) {
- __be16 diff[] = { ~(hdr->h_proto), ethertype };
-
- skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
- }
-
- hdr->h_proto = ethertype;
-}
-
static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_action_push_mpls *mpls)
{
@@ -190,31 +178,10 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
{
int err;
- err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
- if (unlikely(err))
+ err = skb_mpls_pop(skb, ethertype);
+ if (err)
return err;
- skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
-
- memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
- skb->mac_len);
-
- __skb_pull(skb, MPLS_HLEN);
- skb_reset_mac_header(skb);
- skb_set_network_header(skb, skb->mac_len);
-
- if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET) {
- struct ethhdr *hdr;
-
- /* mpls_hdr() is used to locate the ethertype field correctly in the
- * presence of VLAN tags.
- */
- hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
- update_ethertype(skb, hdr, ethertype);
- }
- if (eth_p_mpls(skb->protocol))
- skb->protocol = ethertype;
-
invalidate_flow_key(key);
return 0;
}
--
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