ipsec: fixed chaining ops after add footer and icv

In case there is no free space in first buffer for ICV and footer,
additional buffer will be added, but esp_encrypt will stay in single
buffer mode.
The issue happens for the following payload sizes:
 - TCP packets with payload 1992
 - ICMP packets with payload 2004

This fix moves the single/chained buffer ops selection to after
esp_add_footer_and_icv call.

Type: fix

Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
Signed-off-by: PiotrX Kleski <piotrx.kleski@intel.com>
Change-Id: Ic5ceba418f738933f96edb3e489ca2d149033b79

1 files changed, 11 insertions, 8 deletions

diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c
index e9feb8b40a1..e80f98624b9 100644
--- a/src/vnet/ipsec/esp_encrypt.c
+++ b/src/vnet/ipsec/esp_encrypt.c
@@ -695,18 +695,10 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
       if (n_bufs > 1)
 	{
-	  crypto_ops = &ptd->chained_crypto_ops;
-	  integ_ops = &ptd->chained_integ_ops;
-
 	  /* find last buffer in the chain */
 	  while (lb->flags & VLIB_BUFFER_NEXT_PRESENT)
 	    lb = vlib_get_buffer (vm, lb->next_buffer);
 	}
-      else
-	{
-	  crypto_ops = &ptd->crypto_ops;
-	  integ_ops = &ptd->integ_ops;
-	}
 
       if (PREDICT_FALSE (esp_seq_advance (sa0)))
 	{
@@ -879,6 +871,17 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  next[0] = ESP_ENCRYPT_NEXT_INTERFACE_OUTPUT;
 	}
 
+      if (lb != b[0])
+	{
+	  crypto_ops = &ptd->chained_crypto_ops;
+	  integ_ops = &ptd->chained_integ_ops;
+	}
+      else
+	{
+	  crypto_ops = &ptd->crypto_ops;
+	  integ_ops = &ptd->integ_ops;
+	}
+
       esp->spi = spi;
       esp->seq = clib_net_to_host_u32 (sa0->seq);