[PATCH v4 net-next 10/11] net: Add GRE keyid in flow_keys

[Tom Herbert]

In flow dissector if a GRE header contains a keyid this is saved in the
new keyid field of flow_keys. The GRE keyid is then represented
in the flow hash function input.

Signed-off-by: Tom Herbert <t...@herbertland.com>
---
 include/net/flow_dissector.h |  6 ++++++
 net/core/flow_dissector.c    | 24 +++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 14d8483..5d4257b 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -32,6 +32,10 @@ struct flow_dissector_key_tags {
                flow_label:20;
 };
 
+struct flow_dissector_key_keyid {
+       u32     keyid;
+};
+
 /**
  * struct flow_dissector_key_ipv4_addrs:
  * @src: source ip address
@@ -113,6 +117,7 @@ enum flow_dissector_key_id {
        FLOW_DISSECTOR_KEY_TIPC_ADDRS, /* struct flow_dissector_key_tipc_addrs 
*/
        FLOW_DISSECTOR_KEY_VLANID, /* struct flow_dissector_key_flow_tags */
        FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_flow_tags */
+       FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */
 
        FLOW_DISSECTOR_KEY_MAX,
 };
@@ -150,6 +155,7 @@ struct flow_keys {
 #define FLOW_KEYS_HASH_START_FIELD basic
        struct flow_dissector_key_basic basic;
        struct flow_dissector_key_tags tags;
+       struct flow_dissector_key_keyid keyid;
        struct flow_dissector_key_ports ports;
        struct flow_dissector_key_addrs addrs;
 };
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index ba089d9..ea318d5 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -127,6 +127,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
        struct flow_dissector_key_addrs *key_addrs;
        struct flow_dissector_key_ports *key_ports;
        struct flow_dissector_key_tags *key_tags;
+       struct flow_dissector_key_keyid *key_keyid;
        u8 ip_proto;
 
        if (!data) {
@@ -315,8 +316,25 @@ ipv6:
                nhoff += 4;
                if (hdr->flags & GRE_CSUM)
                        nhoff += 4;
-               if (hdr->flags & GRE_KEY)
+               if (hdr->flags & GRE_KEY) {
+                       const __be32 *keyid;
+                       __be32 _keyid;
+
+                       keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
+                                                    data, hlen, &_keyid);
+
+                       if (!keyid)
+                               return false;
+
+                       if (skb_flow_dissector_uses_key(flow_dissector,
+                                                       
FLOW_DISSECTOR_KEY_GRE_KEYID)) {
+                               key_keyid = 
skb_flow_dissector_target(flow_dissector,
+                                                                     
FLOW_DISSECTOR_KEY_GRE_KEYID,
+                                                                     
target_container);
+                               key_keyid->keyid = ntohl(*keyid);
+                       }
                        nhoff += 4;
+               }
                if (hdr->flags & GRE_SEQ)
                        nhoff += 4;
                if (proto == htons(ETH_P_TEB)) {
@@ -650,6 +668,10 @@ static const struct flow_dissector_key 
flow_keys_dissector_keys[] = {
                .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
                .offset = offsetof(struct flow_keys, tags),
        },
+       {
+               .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
+               .offset = offsetof(struct flow_keys, keyid),
+       },
 };
 
 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
-- 
1.8.1

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