src/vfer_packet.h

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/*
 * Copyright 2005, 2006, Internet2
 * Legal conditions are in file LICENSE
 * (MD5 = c434f2e53b8089d8b4d0172c7ce07360).
 */
/**
 *
 * @file   vfer_packet.h
 * @author Ivan Beschastnikh
 * @brief  Defines packet structures for the protocol.
 *
 * Supports packet.c and defines structures used by c_control.c. 
 *
 * -     07/26/06        ivan            removed vector ack packet type declarations and related functions
 * -     09/01/05        ivan            created new packet structures
 * -     05/18/05        ivan            created
 */

#ifndef VFER_PACKET_H
#define VFER_PACKET_H

#include <limits.h>
#include <netinet/in.h>
#include <sys/uio.h>            /* writev */

#include "vfer_datagram.h"
#include "vfer.h"

/* all lengths are in bytes */
/* top most (generic) header for VFer */
#define TOPH_LENGTH             16 /* includes an 8 byte timestamp  */

/* packet specific header lengths not including generic header: */
#define REQUESTH_LENGTH         14
#define RESPONSEH_LENGTH        20
#define DATAH_LENGTH            10 /* counting the optional frame_len field */
#define CCACKH_LENGTH           22 /* counting the optional frame_len field, but not any of the nack data range related variables */
#define CLOSEH_LENGTH           0

#define DATAACKH_LENGTH         DATAH_LENGTH + SYNCH_LENGTH /* not counting the optional frame length field */

/* data and dataack lengths are minimums */
#define REQUEST_LENGTH          REQUESTH_LENGTH + TOPH_LENGTH
#define RESPONSE_LENGTH         RESPONSEH_LENGTH + TOPH_LENGTH
#define DATA_LENGTH             DATAH_LENGTH + TOPH_LENGTH
#define DATAACK_LENGTH          DATAACKH_LENGTH + TOPH_LENGTH
#define CCACK_LENGTH            CCACKH_LENGTH + TOPH_LENGTH
#define CLOSE_LENGTH            CLOSEH_LENGTH + TOPH_LENGTH

/*
 * data structures
 */

/**
 * @brief request packet type
 */
typedef struct request_pack {
        uint32_t max_frame_size;
        uint32_t recv_buf_size;
        uint32_t send_buf_size;
        uint16_t init_frame_num;
} request_pack;

/**
 * @brief response packet type
 */
typedef struct response_pack {
        uint16_t init_frame_num;
        uint16_t connection_port;
        uint32_t max_frame_size;
        uint32_t recv_buf_size;
        uint32_t send_buf_size;
        int32_t request_delay;  /* this delay measurement (in microseconds) is used to estimate RTT after the handshake is completed */
} response_pack;

/**
 * @brief data packet type
 */
typedef struct data_pack {
        uint16_t frame_num;
        uint32_t data_offset;
        uint32_t frame_len;     /* optional: 0 if not set in the packet ; o.w > 0 */
        void*    data;
        uint32_t data_len;      /* this is not actually in the packet (its computed and set on reception) */
} data_pack;

/**
 * @brief congestion control ack packet type
 */
typedef struct ccack_pack {
        uint32_t last_seq;              /* last sequence number that the sender of the ack received */
        uint16_t packets_lost;          /* note this field is cumulative: total number of packets lost since beginning of connection */
        uint16_t oldest_frame;          /* oldest frame that the sender of the ack is interested in */
        uint16_t newest_frame;          /* newest frame that the sender of the ack has seen */
        int32_t  delay_delta;           /* current delay delta (current_delay - base_delay) in us for the reverse data path */
        int32_t  delay;                 /* current delay (as apposed to base delay) in us for the reverse data path */
        uint32_t bytes_total;           /* total number of data bytes recvd for this connection */
        /* inherited from vecack_pack structure */
        uint16_t intervals_frame_num;
        uint32_t interval_count;
        uint32_t* raw_intervals;
} ccack_pack;

/**
 * @brief close packet type
 */
typedef struct close_pack {
} close_pack;

/**
 * @brief generic vfer packet type
 */
typedef struct packet {
        unsigned char type;
        unsigned char version;
        uint32_t opts;
        uint32_t seq;
        /** seconds receipt timestamp */
        uint32_t tv_sec;
        /** microseconds receipt timestamp */
        uint32_t tv_usec;
        /** delay in us for this packet, only defined on the receiver after being processed by packet.c which sets this field */
        int32_t delay;
        /** contains the raw packet received/sent and the corresponding length[s] */
        struct iovec* iov;
        int iovlen;
        union {
                request_pack    req;
                response_pack   res;
                data_pack       data;
                ccack_pack      ccack;
                close_pack      close;
        } u;
} packet;

/* packet types MUST be multiples of 16 - see packetizing of the
 * VFer header in the spec rev. 1.7 and greater, the packet_type
 * cannot be more than 240 = (16 * 15) */
typedef enum packet_type {REQUEST       =16,
                          RESPONSE      =32,
                          DATA          =48,
                          CC_ACK        =64,
                          DATA_ACK      =96,
                          CLOSE         =112} packet_type;

typedef enum packet_opt {OPT_FRAME_LEN = 1,
                         OPT_SYNC = 2,
                         OPT_VEC = 4} packet_opt;

/*
 * function prototypes
 */

/* printing functions */
char*   Packet_Str_Type         (packet* p);
char*   Packet_Str              (packet* p);
void    Packet_Print            (packet* p);

/* packet formation functions */
packet* Packet_Form_Request     (uint32_t opts, uint32_t init_seq_num,
                                 uint32_t max_frame_size, uint32_t recv_buf_size,
                                 uint32_t send_buf_size, uint16_t init_frame_num);
packet* Packet_Form_Response    (uint32_t opts, uint32_t init_seq_num, uint16_t init_frame_num,
                                 uint16_t connection_port, uint32_t max_frame_size, uint32_t recv_buf_size, uint32_t send_buf_size, int32_t request_delay);
packet* Packet_Form_Data        (uint32_t opts, uint32_t seq_num, uint16_t frame_num,
                                 uint32_t data_offset, uint32_t frame_len, void* data, int data_len);
packet* Packet_Form_CCAck       (uint32_t opts, uint32_t seq_num, uint32_t last_seq_received,
                                 uint16_t packets_lost, uint16_t oldest_frame, uint16_t newest_frame, int32_t delay_delta, int32_t delay, uint32_t bytes_total, uint16_t intervals_frame_num, intervals_t* intervals);
packet* Packet_Form_Close       (uint32_t opts, uint32_t seq_num);

/* packet translation functions (interpreters) */
int Packet_Translate_Request    (packet* p);
int Packet_Translate_Response   (packet* p);
int Packet_Translate_Data       (packet* p);
int Packet_Translate_CCAck      (packet* p);
int Packet_Translate_Close      (packet* p);

/* receiver/sender of packets */
int Packet_Read                 (int fd, packet** p, struct sockaddr* addr, socklen_t* addr_len);
int Packet_Read_ICMP    (int icmp_fd, void *pmtu);
int Packet_Write                (packet* p, int fd, struct sockaddr* addr, socklen_t addr_len);

/* rand frame/seq num generatoes */
inline uint16_t Packet_Gen_FrameNum();
inline uint32_t Packet_Gen_SeqNum();

/* helpers that need visibility outside the scope of packet.c */
inline void Packet_Set_Seq      (packet* p, uint32_t seq);

/* variables */

char pack_buf[65536];           /* 64K UDP packet buffer to read packets from the wire */

#endif  /* VFER_PACKET_H */

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