Fix VPP-1515 IPSec receive packet error in transport mode with udp encap

[vpp.git] / src / vnet / ipsec / esp_decrypt.c

diff --git a/src/vnet/ipsec/esp_decrypt.c b/src/vnet/ipsec/esp_decrypt.c
index 68cb825..3f46350 100644 (file)
--- a/src/vnet/ipsec/esp_decrypt.c
+++ b/src/vnet/ipsec/esp_decrypt.c
@@ -277,9 +277,19 @@ esp_decrypt_inline (vlib_main_t * vm,
                    }
                  else
                    {
-                     ih4 =
-                       (ip4_header_t *) ((u8 *) esp0 -
-                                         sizeof (ip4_header_t));
+                     if (sa0->udp_encap)
+                       {
+                         ih4 =
+                           (ip4_header_t *) ((u8 *) esp0 -
+                                             sizeof (udp_header_t) -
+                                             sizeof (ip4_header_t));
+                       }
+                     else
+                       {
+                         ih4 =
+                           (ip4_header_t *) ((u8 *) esp0 -
+                                             sizeof (ip4_header_t));
+                       }
                      oh4 = vlib_buffer_get_current (o_b0);
                      ip_hdr_size = sizeof (ip4_header_t);
                    }