ip: add extended shallow reassembly

This patch adds some fixes and improvements:

Fixes bug where save_rewrite_length gets overwritten on reassembly
handoff.

Fixes bug where duplicate fragments could cause a reassembly context
to be lost, because the race losing thread would remove bihash entry
created by winning thread.

Improves tracing by adding more events.

Adds extended shallow reassembly. This is a toggleable option, which if
turned on will cause reassembly to wait for both first and last
fragments to calculate total IP payload length. Furthermore it'll store
a local copy of first fragment and necessary data to retrieve it in
vnet_buffer2. This allows downstream features to access full L3/L4
headers when dealing with fragments.

Type: fix
Change-Id: I81695070533410c5815291dbc65ea71c87e3ae05
Signed-off-by: Klement Sekera <klement.sekera@gmail.com>

1 files changed, 18 insertions, 2 deletions

diff --git a/src/vnet/buffer.h b/src/vnet/buffer.h
index e60b8ffb810..247af56f403 100644
--- a/src/vnet/buffer.h
+++ b/src/vnet/buffer.h
@@ -241,7 +241,8 @@ typedef struct
 		u8 ip_proto;	/* protocol in ip header */
 		u8 icmp_type_or_tcp_flags;
 		u8 is_non_first_fragment : 1;
-		u8 l4_layer_truncated : 7;
+		u8 l4_hdr_truncated : 1;
+		u8 unused : 6;
 		u32 tcp_seq_number;
 	      };
 	      /* full reassembly output variables */
@@ -492,7 +493,22 @@ typedef struct
     };
   } nat;
 
-  u32 unused[8];
+  struct
+  {
+    /*
+     * Shallow virtual reassembly output values.
+     * Only populated if extended reassembly enabled via
+     * ipX_sv_reass_enable_disable_extended().
+     */
+    struct
+    {
+      u32 thread_index;
+      u32 pool_index;
+      u32 id;
+    } reass;
+  } ip;
+
+  u32 unused[5];
 } vnet_buffer_opaque2_t;
 
 #define vnet_buffer2(b) ((vnet_buffer_opaque2_t *) (b)->opaque2)