crypto: use fixed crypto frame pool

The async frames pool may be resized once drained. This will cause 2 problems: original pool pointer is invalidated and pool size changed, both problems will confuse the crypto infra user graph nodes (like IPsec and Wireguard) and crypto engines if they expect the pool pointers always valid and the pool size never changed (for performance reason).

This patch introduces fixed size of the async frames pool. This helps zeroing surprise to the components shown above and avoiding segmentation fault when pool resizing happened. In addition, the crypto engine may take advantage of the feature to sync its own pool/vector with crypto infra.

Type: improvement

Signed-off-by: Gabriel Oginski <gabrielx.oginski@intel.com>
Signed-off-by: Piotr Bronowski <piotrx.bronowski@intel.com>
Change-Id: I2a71783b90149fa376848b9c4f84ce8c6c034bef

src/plugins/wireguard/wireguard_input.c

@@ -611,6 +611,8 @@ wg_input_process (vlib_main_t *vm, wg_per_thread_data_t *ptd,
 	{
 	  *async_frame = vnet_crypto_async_get_frame (
 	    vm, VNET_CRYPTO_OP_CHACHA20_POLY1305_TAG16_AAD0_DEC);
+	  if (PREDICT_FALSE (NULL == *async_frame))
+	    goto error;
 	  /* Save the frame to the list we'll submit at the end */
 	  vec_add1 (ptd->async_frames, *async_frame);
 	}

src/plugins/wireguard/wireguard_output_tun.c

@@ -368,6 +368,8 @@ wg_add_to_async_frame (vlib_main_t *vm, wg_per_thread_data_t *ptd,
     {
       *async_frame = vnet_crypto_async_get_frame (
 	vm, VNET_CRYPTO_OP_CHACHA20_POLY1305_TAG16_AAD0_ENC);
+      if (PREDICT_FALSE (NULL == *async_frame))
+	goto error;
       /* Save the frame to the list we'll submit at the end */
       vec_add1 (ptd->async_frames, *async_frame);
     }

src/vnet/crypto/crypto.c

@@ -706,8 +706,7 @@ vnet_crypto_init (vlib_main_t * vm)
   cm->async_alg_index_by_name = hash_create_string (0, sizeof (uword));
   vec_validate_aligned (cm->threads, tm->n_vlib_mains, CLIB_CACHE_LINE_BYTES);
   vec_foreach (ct, cm->threads)
-    pool_alloc_aligned (ct->frame_pool, VNET_CRYPTO_FRAME_POOL_SIZE,
-			CLIB_CACHE_LINE_BYTES);
+    pool_init_fixed (ct->frame_pool, VNET_CRYPTO_FRAME_POOL_SIZE);
   vec_validate (cm->algs, VNET_CRYPTO_N_ALGS);
   vec_validate (cm->async_algs, VNET_CRYPTO_N_ASYNC_ALGS);
 

src/vnet/crypto/crypto.h

@@ -556,12 +556,16 @@ vnet_crypto_async_get_frame (vlib_main_t * vm, vnet_crypto_async_op_id_t opt)
   vnet_crypto_thread_t *ct = cm->threads + vm->thread_index;
   vnet_crypto_async_frame_t *f = NULL;
 
-  pool_get_aligned (ct->frame_pool, f, CLIB_CACHE_LINE_BYTES);
-  if (CLIB_DEBUG > 0)
-    clib_memset (f, 0xfe, sizeof (*f));
-  f->state = VNET_CRYPTO_FRAME_STATE_NOT_PROCESSED;
-  f->op = opt;
-  f->n_elts = 0;
+  if (PREDICT_TRUE (pool_free_elts (ct->frame_pool)))
+    {
+      pool_get_aligned (ct->frame_pool, f, CLIB_CACHE_LINE_BYTES);
+#if CLIB_DEBUG > 0
+      clib_memset (f, 0xfe, sizeof (*f));
+#endif
+      f->state = VNET_CRYPTO_FRAME_STATE_NOT_PROCESSED;
+      f->op = opt;
+      f->n_elts = 0;
+    }
 
   return f;
 }

src/vnet/ipsec/esp_decrypt.c

@@ -1183,6 +1183,15 @@ esp_decrypt_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	    {
 	      async_frames[async_op] =
 		vnet_crypto_async_get_frame (vm, async_op);
+	      if (PREDICT_FALSE (!async_frames[async_op]))
+		{
+		  err = ESP_DECRYPT_ERROR_NO_AVAIL_FRAME;
+		  esp_decrypt_set_next_index (
+		    b[0], node, thread_index, err, n_noop, noop_nexts,
+		    ESP_DECRYPT_NEXT_DROP, current_sa_index);
+		  goto next;
+		}
+
 	      /* Save the frame to the list we'll submit at the end */
 	      vec_add1 (ptd->async_frames, async_frames[async_op]);
 	    }

src/vnet/ipsec/esp_encrypt.c

@@ -999,6 +999,16 @@ esp_encrypt_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	    {
 	      async_frames[async_op] =
 		vnet_crypto_async_get_frame (vm, async_op);
+
+	      if (PREDICT_FALSE (!async_frames[async_op]))
+		{
+		  err = ESP_ENCRYPT_ERROR_NO_AVAIL_FRAME;
+		  esp_encrypt_set_next_index (b[0], node, thread_index, err,
+					      n_noop, noop_nexts, drop_next,
+					      current_sa_index);
+		  goto trace;
+		}
+
 	      /* Save the frame to the list we'll submit at the end */
 	      vec_add1 (ptd->async_frames, async_frames[async_op]);
 	    }

src/vnet/ipsec/ipsec.api

@@ -607,6 +607,12 @@ counters esp_decrypt {
     units "packets";
     description "unsupported payload";
   };
+  no_avail_frame {
+  severity error;
+  type counter64;
+  units "packets";
+  description "no available frame (packet dropped)";
+  };
 };
 
 counters esp_encrypt {
@@ -664,6 +670,12 @@ counters esp_encrypt {
     units "packets";
     description "no Encrypting SA (packet dropped)";
   };
+  no_avail_frame {
+  severity error;
+  type counter64;
+  units "packets";
+  description "no available frame (packet dropped)";
+  };
 };
 
 counters ah_encrypt {