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, 28 insertions, 0 deletions

diff --git a/src/vnet/ip/reass/ip4_sv_reass.h b/src/vnet/ip/reass/ip4_sv_reass.h
index 3a684eb9809..a1e5659a9f1 100644
--- a/src/vnet/ip/reass/ip4_sv_reass.h
+++ b/src/vnet/ip/reass/ip4_sv_reass.h
@@ -23,6 +23,7 @@
 #ifndef __included_ip4_sv_reass_h__
 #define __included_ip4_sv_reass_h__
 
+#include <stdbool.h>
 #include <vnet/api_errno.h>
 #include <vnet/vnet.h>
 
@@ -48,6 +49,33 @@ int ip4_sv_reass_enable_disable_with_refcnt (u32 sw_if_index, int is_enable);
 int ip4_sv_reass_output_enable_disable_with_refcnt (u32 sw_if_index,
 						    int is_enable);
 
+/*
+ * Enable or disable extended reassembly.
+ *
+ * Extended reassembly means that fragments are cached until both first and
+ * last fragments are seen. Furthermore, first fragment buffer will be cloned
+ * and stored in reassembly context for later retrieval.
+ */
+void ip4_sv_reass_enable_disable_extended (bool is_enable);
+
+struct ip4_sv_lock_unlock_args
+{
+  u32 *total_ip_payload_length;
+  u32 *first_fragment_buffer_index;
+  u32 *first_fragment_total_ip_header_length;
+};
+
+/*
+ * Lock thread-level lock and fetch information from reassembly context.
+ * Uses vnet_buffer2 data filled by extended reassembly.
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+int ip4_sv_reass_extended_lock (vlib_buffer_t *b,
+				struct ip4_sv_lock_unlock_args *a);
+
+void ip4_sv_reass_extended_unlock (vlib_buffer_t *b);
+
 uword ip4_sv_reass_custom_register_next_node (uword node_index);
 uword ip4_sv_reass_custom_context_register_next_node (uword node_index);