text: /*
   * Copyright (c) 2015 Cisco and/or its affiliates.
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  #ifndef __ESP_H__
  #define __ESP_H__
  
  #include <vnet/ip/ip.h>
  #include <vnet/crypto/crypto.h>
  #include <vnet/ipsec/ipsec.h>
  
  typedef struct
  {
    union
    {
      u32 spi;
      u8 spi_bytes[4];
    };
    u32 seq;
    u8 data[0];
  } esp_header_t;
  
  typedef struct
  {
    u8 pad_length;
    u8 next_header;
  } esp_footer_t;
  
  /* *INDENT-OFF* */
  typedef CLIB_PACKED (struct {
    ip4_header_t ip4;
    esp_header_t esp;
  }) ip4_and_esp_header_t;
  /* *INDENT-ON* */
  
  /* *INDENT-OFF* */
  typedef CLIB_PACKED (struct {
    ip4_header_t ip4;
    udp_header_t udp;
    esp_header_t esp;
  }) ip4_and_udp_and_esp_header_t;
  /* *INDENT-ON* */
  
  /* *INDENT-OFF* */
  typedef CLIB_PACKED (struct {
    ip6_header_t ip6;
    esp_header_t esp;
  }) ip6_and_esp_header_t;
  /* *INDENT-ON* */
  
  /**
   * AES counter mode nonce
   */
  typedef struct
  {
    u32 salt;
    u64 iv;
    u32 ctr; /* counter: 1 in big-endian for ctr, unused for gcm */
  } __clib_packed esp_ctr_nonce_t;
  
  STATIC_ASSERT_SIZEOF (esp_ctr_nonce_t, 16);
  
  /**
   * AES GCM Additional Authentication data
   */
  typedef struct esp_aead_t_
  {
    /**
     * for GCM: when using ESN it's:
     *   SPI, seq-hi, seg-low
     * else
     *   SPI, seq-low
     */
    u32 data[3];
  } __clib_packed esp_aead_t;
  
  #define ESP_SEQ_MAX		(4294967295UL)
  #define ESP_MAX_BLOCK_SIZE	(16)
  #define ESP_MAX_IV_SIZE		(16)
  #define ESP_MAX_ICV_SIZE	(32)
  
  u8 *format_esp_header (u8 * s, va_list * args);
  
  /* TODO seq increment should be atomic to be accessed by multiple workers */
  always_inline int
  esp_seq_advance (ipsec_sa_t * sa)
  {
    if (PREDICT_TRUE (ipsec_sa_is_set_USE_ESN (sa)))
      {
        if (PREDICT_FALSE (sa->seq == ESP_SEQ_MAX))
  	{
  	  if (PREDICT_FALSE (ipsec_sa_is_set_USE_ANTI_REPLAY (sa) &&
  			     sa->seq_hi == ESP_SEQ_MAX))
  	    return 1;
  	  sa->seq_hi++;
  	}
        sa->seq++;
      }
    else
      {
        if (PREDICT_FALSE (ipsec_sa_is_set_USE_ANTI_REPLAY (sa) &&
  			 sa->seq == ESP_SEQ_MAX))
  	return 1;
        sa->seq++;
      }
  
    return 0;
  }
  
  always_inline u16
  esp_aad_fill (u8 *data, const esp_header_t *esp, const ipsec_sa_t *sa,
  	      u32 seq_hi)
  {
    esp_aead_t *aad;
  
    aad = (esp_aead_t *) data;
    aad->data[0] = esp->spi;
  
    if (ipsec_sa_is_set_USE_ESN (sa))
      {
        /* SPI, seq-hi, seq-low */
        aad->data[1] = (u32) clib_host_to_net_u32 (seq_hi);
        aad->data[2] = esp->seq;
        return 12;
      }
    else
      {
        /* SPI, seq-low */
        aad->data[1] = esp->seq;
        return 8;
      }
  }
  
  /* Special case to drop or hand off packets for sync/async modes.
   *
   * Different than sync mode, async mode only enqueue drop or hand-off packets
   * to next nodes.
   */
  always_inline void
  esp_set_next_index (vlib_buffer_t *b, vlib_node_runtime_t *node, u32 err,
  		    u16 index, u16 *nexts, u16 drop_next)
  {
    nexts[index] = drop_next;
    b->error = node->errors[err];
  }
  
  /* when submitting a frame is failed, drop all buffers in the frame */
  always_inline u32
  esp_async_recycle_failed_submit (vlib_main_t *vm, vnet_crypto_async_frame_t *f,
  				 vlib_node_runtime_t *node, u32 err, u16 index,
  				 u32 *from, u16 *nexts, u16 drop_next_index)
  {
    u32 n_drop = f->n_elts;
    u32 *bi = f->buffer_indices;
  
    while (n_drop--)
      {
        from[index] = bi[0];
        esp_set_next_index (vlib_get_buffer (vm, bi[0]), node, err, index, nexts,
  			  drop_next_index);
        bi++;
        index++;
      }
    vnet_crypto_async_reset_frame (f);
  
    return (f->n_elts);
  }
  
  /**
   * The post data structure to for esp_encrypt/decrypt_inline to write to
   * vib_buffer_t opaque unused field, and for post nodes to pick up after
   * dequeue.
   **/
  typedef struct
  {
    union
    {
      struct
      {
        u8 icv_sz;
        u8 iv_sz;
        ipsec_sa_flags_t flags;
        u32 sa_index;
      };
      u64 sa_data;
    };
  
    u32 seq;
    i16 current_data;
    i16 current_length;
    u16 hdr_sz;
    u16 is_chain;
    u32 seq_hi;
  } esp_decrypt_packet_data_t;
  
  STATIC_ASSERT_SIZEOF (esp_decrypt_packet_data_t, 3 * sizeof (u64));
  STATIC_ASSERT_OFFSET_OF (esp_decrypt_packet_data_t, seq, sizeof (u64));
  
  /* we are forced to store the decrypt post data into 2 separate places -
     vlib_opaque and opaque2. */
  typedef struct
  {
    vlib_buffer_t *lb;
    u32 free_buffer_index;
    u8 icv_removed;
  } esp_decrypt_packet_data2_t;
  
  typedef union
  {
    u16 next_index;
    esp_decrypt_packet_data_t decrypt_data;
  } esp_post_data_t;
  
  STATIC_ASSERT (sizeof (esp_post_data_t) <=
  	       STRUCT_SIZE_OF (vnet_buffer_opaque_t, unused),
  	       "Custom meta-data too large for vnet_buffer_opaque_t");
  
  #define esp_post_data(b) \
      ((esp_post_data_t *)((u8 *)((b)->opaque) \
          + STRUCT_OFFSET_OF (vnet_buffer_opaque_t, unused)))
  
  STATIC_ASSERT (sizeof (esp_decrypt_packet_data2_t) <=
  	       STRUCT_SIZE_OF (vnet_buffer_opaque2_t, unused),
  	       "Custom meta-data too large for vnet_buffer_opaque2_t");
  
  #define esp_post_data2(b) \
      ((esp_decrypt_packet_data2_t *)((u8 *)((b)->opaque2) \
          + STRUCT_OFFSET_OF (vnet_buffer_opaque2_t, unused)))
  
  typedef struct
  {
    /* esp post node index for async crypto */
    u32 esp4_post_next;
    u32 esp6_post_next;
    u32 esp4_tun_post_next;
    u32 esp6_tun_post_next;
    u32 esp_mpls_tun_post_next;
  } esp_async_post_next_t;
  
  extern esp_async_post_next_t esp_encrypt_async_next;
  extern esp_async_post_next_t esp_decrypt_async_next;
  
  #endif /* __ESP_H__ */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  