X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvnet%2Ftcp%2Ftcp_pg.c;h=45eaed97b9b263b73d1c45c2bcc8f57cf7488024;hb=a91866fc1fd673a5edab6e3cb61bd41b8ea3def7;hp=3be4592c6799b1878795379b0363994d15c6eaaf;hpb=49cd3bad66cba83f0364d94ed34de2457694f545;p=vpp.git

diff --git a/src/vnet/tcp/tcp_pg.c b/src/vnet/tcp/tcp_pg.c
index 3be4592c679..45eaed97b9b 100644
--- a/src/vnet/tcp/tcp_pg.c
+++ b/src/vnet/tcp/tcp_pg.c
@@ -77,7 +77,11 @@ tcp_pg_edit_function (pg_main_t * pg,
       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)