From: Benoît Ganne <bganne@cisco.com>
Date: Thu, 28 Oct 2021 08:50:47 +0000 (+0200)
Subject: fib: allow vnet rewrite max size to be smaller the pre_data
X-Git-Tag: v22.06-rc0~317
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=6ea5c4744a132ca5f21b8cffab7676a386d6ebf5;p=vpp.git

fib: allow vnet rewrite max size to be smaller the pre_data

There is no reason to enforce vnet rewrite size to be equal to pre_data.
Moreover, since vnet rewrite size is now saved as u8, this limits
pre_data to 192 bytes.

Type: fix
Fixes: 7dbf9a1a4fff5c3b20ad972289e49e3f88e82f2d

Change-Id: I3f848aa905ea4a794f3b4aa62c929a481261a3f1
Signed-off-by: Benoît Ganne <bganne@cisco.com>
---

diff --git a/src/vnet/adj/rewrite.h b/src/vnet/adj/rewrite.h
index 4234986dc37..5cb90e47318 100644
--- a/src/vnet/adj/rewrite.h
+++ b/src/vnet/adj/rewrite.h
@@ -136,7 +136,7 @@ always_inline void
 vnet_rewrite_clear_data_internal (vnet_rewrite_header_t * rw, int max_size)
 {
   /* Sanity check values carefully for this clib_memset operation */
-  ASSERT ((max_size > 0) && (max_size < VLIB_BUFFER_PRE_DATA_SIZE));
+  ASSERT ((max_size > 0) && (max_size < VNET_REWRITE_TOTAL_BYTES));
 
   rw->data_bytes = 0;
   clib_memset (rw->data, 0xfe, max_size);
@@ -147,7 +147,7 @@ vnet_rewrite_set_data_internal (vnet_rewrite_header_t * rw,
 				int max_size, void *data, int data_bytes)
 {
   /* Sanity check values carefully for this clib_memset operation */
-  ASSERT ((max_size > 0) && (max_size < VLIB_BUFFER_PRE_DATA_SIZE));
+  ASSERT ((max_size > 0) && (max_size < VNET_REWRITE_TOTAL_BYTES));
   ASSERT ((data_bytes >= 0) && (data_bytes < max_size));
 
   rw->data_bytes = data_bytes;
diff --git a/src/vnet/buffer.h b/src/vnet/buffer.h
index 2b3152fbcd6..09abedd5e74 100644
--- a/src/vnet/buffer.h
+++ b/src/vnet/buffer.h
@@ -417,7 +417,9 @@ typedef struct
   };
 } vnet_buffer_opaque_t;
 
-#define VNET_REWRITE_TOTAL_BYTES (VLIB_BUFFER_PRE_DATA_SIZE)
+#define VNET_REWRITE_TOTAL_BYTES 128
+STATIC_ASSERT (VNET_REWRITE_TOTAL_BYTES <= VLIB_BUFFER_PRE_DATA_SIZE,
+	       "VNET_REWRITE_TOTAL_BYTES too big");
 
 STATIC_ASSERT (STRUCT_SIZE_OF (vnet_buffer_opaque_t, ip.save_rewrite_length)
 	       == STRUCT_SIZE_OF (vnet_buffer_opaque_t,