flow_dissector: Add control/reporting of fragmentation

Add an input flag to flow dissector on rather dissection should be
attempted on a first fragment. Also add key_control flags to indicate
that a packet is a fragment or first fragment.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 74fe160..3410227 100644 (file)
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -12,6 +12,8 @@
 struct flow_dissector_key_control {
        u16     thoff;
        u16     addr_type;
+       u32     is_fragment:1;
+       u32     first_frag:1;
 };
 
 /**
@@ -122,6 +124,8 @@ enum flow_dissector_key_id {
        FLOW_DISSECTOR_KEY_MAX,
 };
 
+#define FLOW_DISSECTOR_F_PARSE_1ST_FRAG                BIT(0)
+
 struct flow_dissector_key {
        enum flow_dissector_key_id key_id;
        size_t offset; /* offset of struct flow_dissector_key_*

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index c3d9807..7536a46 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -177,8 +177,6 @@ ip:
                nhoff += iph->ihl * 4;
 
                ip_proto = iph->protocol;
-               if (ip_is_fragment(iph))
-                       ip_proto = 0;
 
                if (!skb_flow_dissector_uses_key(flow_dissector,
                                                 FLOW_DISSECTOR_KEY_IPV4_ADDRS))
@@ -189,6 +187,19 @@ ip:
                memcpy(&key_addrs->v4addrs, &iph->saddr,
                       sizeof(key_addrs->v4addrs));
                key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+
+               if (ip_is_fragment(iph)) {
+                       key_control->is_fragment = 1;
+
+                       if (iph->frag_off & htons(IP_OFFSET)) {
+                               goto out_good;
+                       } else {
+                               key_control->first_frag = 1;
+                               if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
+                                       goto out_good;
+                       }
+               }
+
                break;
        }
        case htons(ETH_P_IPV6): {