Open vSwitch provides code to push an MPLS header to a packet. In
preparation for supporting this in TC, move the push code to an skb helper
that can be reused.
Signed-off-by: John Hurley <john.hur...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
Reviewed-by: Willem de Bruijn <will...@google.com>
Acked-by: Cong Wang <xiyou.wangc...@gmail.com>
---
include/linux/skbuff.h | 1 +
net/core/skbuff.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++
net/openvswitch/actions.c | 31 +++--------------------
3 files changed, 69 insertions(+), 27 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b5d427b..0112256 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3446,6 +3446,7 @@ int skb_ensure_writable(struct sk_buff *skb, int
write_len);
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);
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 5323441..f1d1e47 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -66,6 +66,7 @@
#include <net/checksum.h>
#include <net/ip6_checksum.h>
#include <net/xfrm.h>
+#include <net/mpls.h>
#include <linux/uaccess.h>
#include <trace/events/skb.h>
@@ -5326,6 +5327,69 @@ int skb_vlan_push(struct sk_buff *skb, __be16
vlan_proto, u16 vlan_tci)
}
EXPORT_SYMBOL(skb_vlan_push);
+/* Update the ethertype of hdr and the skb csum value if required. */
+static void skb_mod_eth_type(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;
+}
+
+/**
+ * skb_mpls_push() - push a new MPLS header after the mac header
+ *
+ * @skb: buffer
+ * @mpls_lse: MPLS label stack entry to push
+ * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)
+ *
+ * Expects skb->data at mac header.
+ *
+ * Returns 0 on success, -errno otherwise.
+ */
+int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto)
+{
+ struct mpls_shim_hdr *lse;
+ int err;
+
+ if (unlikely(!eth_p_mpls(mpls_proto)))
+ return -EINVAL;
+
+ /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */
+ if (skb->encapsulation)
+ return -EINVAL;
+
+ err = skb_cow_head(skb, MPLS_HLEN);
+ if (unlikely(err))
+ return err;
+
+ if (!skb->inner_protocol) {
+ skb_set_inner_network_header(skb, skb->mac_len);
+ skb_set_inner_protocol(skb, skb->protocol);
+ }
+
+ skb_push(skb, MPLS_HLEN);
+ memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
+ skb->mac_len);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, skb->mac_len);
+
+ lse = mpls_hdr(skb);
+ lse->label_stack_entry = mpls_lse;
+ skb_postpush_rcsum(skb, lse, MPLS_HLEN);
+
+ if (skb->dev && skb->dev->type == ARPHRD_ETHER)
+ skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);
+ skb->protocol = mpls_proto;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_mpls_push);
+
/**
* alloc_skb_with_frags - allocate skb with page frags
*
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index bd13146..a9a6c9c 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -175,34 +175,11 @@ static void update_ethertype(struct sk_buff *skb, struct
ethhdr *hdr,
static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_action_push_mpls *mpls)
{
- struct mpls_shim_hdr *new_mpls_lse;
-
- /* Networking stack do not allow simultaneous Tunnel and MPLS GSO. */
- if (skb->encapsulation)
- return -ENOTSUPP;
-
- if (skb_cow_head(skb, MPLS_HLEN) < 0)
- return -ENOMEM;
-
- if (!skb->inner_protocol) {
- skb_set_inner_network_header(skb, skb->mac_len);
- skb_set_inner_protocol(skb, skb->protocol);
- }
-
- skb_push(skb, MPLS_HLEN);
- memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
- skb->mac_len);
- skb_reset_mac_header(skb);
- skb_set_network_header(skb, skb->mac_len);
-
- new_mpls_lse = mpls_hdr(skb);
- new_mpls_lse->label_stack_entry = mpls->mpls_lse;
-
- skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);
+ int err;
- if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET)
- update_ethertype(skb, eth_hdr(skb), mpls->mpls_ethertype);
- skb->protocol = mpls->mpls_ethertype;
+ err = skb_mpls_push(skb, mpls->mpls_lse, mpls->mpls_ethertype);
+ if (err)
+ return err;
invalidate_flow_key(key);
return 0;
--
2.7.4
