[PATCH net-next 1/2] flow_dissector: add mpls support

[Benjamin LaHaise]

Add support for parsing MPLS flows to the flow dissector in preparation for
adding MPLS match support to cls_flower.

Signed-off-by: Benjamin LaHaise <benjamin.laha...@netronome.com>
Signed-off-by: Benjamin LaHaise <b...@kvack.org>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index ac97030..00d704f 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -41,6 +41,13 @@ struct flow_dissector_key_vlan {
        u16     padding;
 };
 
+struct flow_dissector_key_mpls {
+       u32     mpls_ttl : 8,
+               mpls_bos : 1,
+               mpls_tc : 3,
+               mpls_label : 20;
+};
+
 struct flow_dissector_key_keyid {
        __be32  keyid;
 };
@@ -169,6 +176,7 @@ enum flow_dissector_key_id {
        FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, /* struct 
flow_dissector_key_ipv6_addrs */
        FLOW_DISSECTOR_KEY_ENC_CONTROL, /* struct flow_dissector_key_control */
        FLOW_DISSECTOR_KEY_ENC_PORTS, /* struct flow_dissector_key_ports */
+       FLOW_DISSECTOR_KEY_MPLS, /* struct flow_dissector_key_mpls */
 
        FLOW_DISSECTOR_KEY_MAX,
 };
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 5f3ae92..15185d8 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -126,9 +126,11 @@ __skb_flow_dissect_mpls(const struct sk_buff *skb,
 {
        struct flow_dissector_key_keyid *key_keyid;
        struct mpls_label *hdr, _hdr[2];
+       u32 entry, label;
 
        if (!dissector_uses_key(flow_dissector,
-                               FLOW_DISSECTOR_KEY_MPLS_ENTROPY))
+                               FLOW_DISSECTOR_KEY_MPLS_ENTROPY) &&
+           !dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS))
                return FLOW_DISSECT_RET_OUT_GOOD;
 
        hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
@@ -136,8 +138,25 @@ __skb_flow_dissect_mpls(const struct sk_buff *skb,
        if (!hdr)
                return FLOW_DISSECT_RET_OUT_BAD;
 
-       if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
-           MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
+       entry = ntohl(hdr[0].entry);
+       label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
+
+       if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) {
+               struct flow_dissector_key_mpls *key_mpls;
+
+               key_mpls = skb_flow_dissector_target(flow_dissector,
+                                                    FLOW_DISSECTOR_KEY_MPLS,
+                                                    target_container);
+               key_mpls->mpls_label = label;
+               key_mpls->mpls_ttl = (entry & MPLS_LS_TTL_MASK)
+                                       >> MPLS_LS_TTL_SHIFT;
+               key_mpls->mpls_tc = (entry & MPLS_LS_TC_MASK)
+                                       >> MPLS_LS_TC_SHIFT;
+               key_mpls->mpls_bos = (entry & MPLS_LS_S_MASK)
+                                       >> MPLS_LS_S_SHIFT;
+       }
+
+       if (label == MPLS_LABEL_ENTROPY) {
                key_keyid = skb_flow_dissector_target(flow_dissector,
                                                      
FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
                                                      target_container);