+
+ if (ipsec_sa_is_set_IS_AEAD (sa0))
+ {
+ esp_header_t *esp0;
+ esp_aead_t *aad;
+ u8 *scratch;
+ u32 salt;
+
+ /*
+ * construct the AAD and the nonce (Salt || IV) in a scratch
+ * space in front of the IP header.
+ */
+ scratch = payload - esp_sz;
+ esp0 = (esp_header_t *) (scratch);
+
+ scratch -= (sizeof (*aad) + pd->hdr_sz);
+ op->aad = scratch;
+
+ esp_aad_fill (op, esp0, sa0);
+
+ /*
+ * we don't need to refer to the ESP header anymore so we
+ * can overwrite it with the salt and use the IV where it is
+ * to form the nonce = (Salt + IV)
+ */
+ salt = clib_host_to_net_u32 (sa0->salt);
+ op->iv -= sizeof (sa0->salt);
+ clib_memcpy_fast (op->iv, &salt, sizeof (sa0->salt));
+ op->iv_len = cpd.iv_sz + sizeof (sa0->salt);
+
+ op->tag = payload + len;
+ op->tag_len = 16;
+ }