commit a91866fc1fd673a5edab6e3cb61bd41b8ea3def7
author Kingwel Xie <kingwel.xie@ericsson.com> Fri Oct 26 23:26:06 2018 -0400
committer Damjan Marion <dmarion@me.com> Sat Oct 27 09:15:03 2018 +0000
tree e5dee75bc3a4f064e6e45c187de630873bea9b5f
parent 49cd3bad66cba83f0364d94ed34de2457694f545

pg: icmp4 & tcp4 ip length issue

length in ip4 header could be 0, when the length edit is fixed
this happens if length is not specified or size is specified as, f.g., 100-100
As a result, tcp and icmp would get a negative value for checksum calculation

Change-Id: I55fa1f5e95717ea4149cb3b8c9b73caf88ae7f98
Signed-off-by: Kingwel Xie <kingwel.xie@ericsson.com>

src/vnet/ip/icmp4.c

diff --git a/src/vnet/ip/icmp4.c b/src/vnet/ip/icmp4.c
index 3626e96..a598ca9 100644
--- a/src/vnet/ip/icmp4.c
+++ b/src/vnet/ip/icmp4.c
@@ -653,7 +653,13 @@
       ASSERT (p0->current_data == 0);
       ip0 = (void *) (p0->data + ip_offset);
       icmp0 = (void *) (p0->data + icmp_offset);
-      len0 = clib_net_to_host_u16 (ip0->length) - ip4_header_bytes (ip0);
+
+      /* if IP length has been specified, then calculate the length based on buffer */
+      if (ip0->length == 0)
+	len0 = vlib_buffer_length_in_chain (vm, p0) - icmp_offset;
+      else
+	len0 = clib_net_to_host_u16 (ip0->length) - icmp_offset;
+
       icmp0->checksum =
 	~ip_csum_fold (ip_incremental_checksum (0, icmp0, len0));
     }

src/vnet/tcp/tcp_pg.c

diff --git a/src/vnet/tcp/tcp_pg.c b/src/vnet/tcp/tcp_pg.c
index 3be4592..45eaed9 100644
--- a/src/vnet/tcp/tcp_pg.c
+++ b/src/vnet/tcp/tcp_pg.c
@@ -77,7 +77,11 @@
       ASSERT (p0->current_data == 0);
       ip0 = (void *) (p0->data + ip_offset);
       tcp0 = (void *) (p0->data + tcp_offset);
-      tcp_len0 = clib_net_to_host_u16 (ip0->length) - sizeof (ip0[0]);
+      /* if IP length has been specified, then calculate the length based on buffer */
+      if (ip0->length == 0)
+	tcp_len0 = vlib_buffer_length_in_chain (vm, p0) - tcp_offset;
+      else
+	tcp_len0 = clib_net_to_host_u16 (ip0->length) - tcp_offset;
 
       /* Initialize checksum with header. */
       if (BITS (sum0) == 32)