text: /* Copyright (c) 2017 - 2019 LiteSpeed Technologies Inc.  See LICENSE. */
  /*
   * lsquic_packet_in.h
   */
  
  #ifndef LSQUIC_PACKET_IN_H
  #define LSQUIC_PACKET_IN_H 1
  
  
  struct lsquic_packet_in;
  struct lsquic_cid;
  
  
  struct data_frame
  {
      const unsigned char *df_data;       /* Pointer to data */
      uint64_t             df_offset;     /* Stream offset */
      uint16_t             df_read_off;   /* Read offset */
      uint16_t             df_size;       /* Size of df_data */
      signed char          df_fin;        /* FIN? */
  };
  
  
  typedef struct stream_frame
  {
      /* Stream frames are stored in a list inside stream. */
      TAILQ_ENTRY(stream_frame)       next_frame;
  
      /* `data' points somewhere into the packet payload.  The packet object
       * is reference-counted.  When the frame is freed, the packet is released
       * via lsquic_packet_put().  If data_length is zero, the frame does not
       * keep a reference to the incoming packet and this pointer is not set.
       */
      struct lsquic_packet_in        *packet_in;
  
      struct data_frame               data_frame;
  
      lsquic_stream_id_t stream_id;     /* Parsed from packet */
  } stream_frame_t;
  
  
  #define DF_OFF(frame) (frame)->data_frame.df_offset
  #define DF_ROFF(frame) (DF_OFF(frame) + (frame)->data_frame.df_read_off)
  #define DF_FIN(frame) (frame)->data_frame.df_fin
  #define DF_SIZE(frame) (frame)->data_frame.df_size
  #define DF_END(frame) (DF_OFF(frame) + DF_SIZE(frame))
  
  
  typedef struct lsquic_packet_in
  {
      TAILQ_ENTRY(lsquic_packet_in)   pi_next;
      lsquic_time_t                   pi_received;   /* Time received */
      lsquic_cid_t                    pi_dcid;
  #define pi_conn_id pi_dcid
      lsquic_packno_t                 pi_packno;
      enum quic_ft_bit                pi_frame_types;
      unsigned short                  pi_header_sz;  /* Points to payload */
      unsigned short                  pi_data_sz;    /* Data plus header */
      /* A packet may be referred to by one or more frames and packets_in
       * list.
       */
      unsigned short                  pi_refcnt;
      unsigned short                  pi_hsk_stream; /* Offset to handshake stream
                                                      * frame, only valid if
                                                      * PI_HSK_STREAM is set.
                                                      */
      enum {
          PI_DECRYPTED    = (1 << 0),
          PI_OWN_DATA     = (1 << 1),                /* We own pi_data */
          PI_CONN_ID      = (1 << 2),                /* pi_conn_id is set */
          PI_HSK_STREAM   = (1 << 3),                /* Has handshake data (mini only) */
          PI_FROM_MINI    = (1 << 4),                /* Handed off by mini connection */
  #define PIBIT_ENC_LEV_SHIFT 5
          PI_ENC_LEV_BIT_0= (1 << 5),                /* Encodes encryption level */
          PI_ENC_LEV_BIT_1= (1 << 6),                /*  (see enum enc_level). */
          PI_GQUIC        = (1 << 7),
          PI_UNUSED_8     = (1 << 8),                /* <-- hole, reuse me! */
  #define PIBIT_ECN_SHIFT 9
          PI_ECN_BIT_0    = (1 << 9),
          PI_ECN_BIT_1    = (1 <<10),
  #define PIBIT_SPIN_SHIFT 11
          PI_SPIN_BIT     = (1 <<11),
  #define PIBIT_BITS_SHIFT 12
          PI_BITS_BIT_0   = (1 <<12),
          PI_BITS_BIT_1   = (1 <<13),
      }                               pi_flags:16;
      /* pi_token and pi_token_size are set in Initial and Retry packets */
      unsigned short                  pi_token_size; /* Size of the token */
      unsigned char                   pi_token;      /* Offset to token */
      /* pi_odcid and pi_odcid_len are only set in Retry packets */
      unsigned char                   pi_odcid;      /* Offset to Original DCID */
      unsigned char                   pi_odcid_len;  /* Size of ODCID */
      unsigned char                   pi_scid_off;   /* Offset to SCID */
      unsigned char                   pi_scid_len;   /* Size of SCID */
      unsigned char                   pi_quic_ver;   /* Offset to QUIC version */
      unsigned char                   pi_nonce;      /* Offset to nonce */
      enum header_type                pi_header_type:8;
      unsigned char                   pi_path_id;
      /* If PI_OWN_DATA flag is not set, `pi_data' points to user-supplied
       * packet data, which is NOT TO BE MODIFIED.
       */
      unsigned char                  *pi_data;
  } lsquic_packet_in_t;
  
  
  #define lsquic_packet_in_public_flags(p) ((p)->pi_data[0])
  
  #define lsquic_packet_in_is_gquic_prst(p) \
      (((p)->pi_flags & PI_GQUIC) \
          && (lsquic_packet_in_public_flags(p) & PACKET_PUBLIC_FLAGS_RST))
  
  #define lsquic_packet_in_is_verneg(p) \
      (((p)->pi_flags & PI_GQUIC) ? \
          lsquic_packet_in_public_flags(p) & PACKET_PUBLIC_FLAGS_VERSION : \
          (p)->pi_header_type == HETY_VERNEG)
  
  #define lsquic_packet_in_packno_bits(p) \
                          (((p)->pi_flags >> PIBIT_BITS_SHIFT) & 3)
  
  #define lsquic_packet_in_upref(p) (++(p)->pi_refcnt)
  
  #define lsquic_packet_in_get(p) (lsquic_packet_in_upref(p), (p))
  
  #define lsquic_packet_in_nonce(p) \
                      ((p)->pi_nonce ? (p)->pi_data + (p)->pi_nonce : NULL)
  
  #define lsquic_packet_in_enc_level(p) \
      (((p)->pi_flags >> PIBIT_ENC_LEV_SHIFT) & 0x3)
  
  #define lsquic_packet_in_ecn(p) \
      (((p)->pi_flags >> PIBIT_ECN_SHIFT) & 0x3)
  
  #define lsquic_packet_in_spin_bit(p) (((p)->pi_flags & PI_SPIN_BIT) > 0)
  
  /* PATH_CHALLENGE, PATH_RESPONSE, NEW_CONNECTION_ID, and PADDING frames
   * are "probing frames", and all other frames are "non-probing frames".
   * A packet containing only probing frames is a "probing packet", and a
   * packet containing any other frame is a "non-probing packet".
   *
   * [draft-ietf-quic-transport-20], Section 9.1
   */
  #define lsquic_packet_in_non_probing(p) \
     (!!((p)->pi_frame_types & ~(QUIC_FTBIT_PATH_CHALLENGE                \
                          |QUIC_FTBIT_PATH_RESPONSE|QUIC_FTBIT_PADDING    \
                          |QUIC_FTBIT_NEW_CONNECTION_ID)))
  
  /* The version iterator is used on a version negotiation packet only.
   * The iterator functions return 1 when next version is returned and
   * 0 when there are no more versions.
   */
  struct ver_iter
  {
      const struct lsquic_packet_in  *packet_in;
      unsigned                        off;
  };
  
  int
  packet_in_ver_first (const lsquic_packet_in_t *packet_in, struct ver_iter *,
                       lsquic_ver_tag_t *ver_tag);
  
  int
  packet_in_ver_next (struct ver_iter *, lsquic_ver_tag_t *ver_tag);
  
  size_t
  lsquic_packet_in_mem_used (const struct lsquic_packet_in *);
  
  void
  lsquic_scid_from_packet_in (const struct lsquic_packet_in *,
                                                      struct lsquic_cid *);
  
  #endif
  