common.h

#ifndef __COMMON_H__
#define __COMMON_H__

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <unistd.h>
#include <netdb.h>
#include <math.h>
#include <sys/time.h>
#include "crc.h"

#define MAX_COMMAND_LENGTH 16
#define AUTOMATED_FILENAME 512
typedef unsigned char uchar_t;

typedef int bool;
#define true 1
#define false 0

//System configuration information
struct SysConfig_t
{
    float drop_prob;
    float corrupt_prob;
    unsigned char automated;
    char automated_file[AUTOMATED_FILENAME];
};
typedef struct SysConfig_t  SysConfig;

//Command line input information
struct Cmd_t
{
    uint16_t src_id;
    uint16_t dst_id;
    char * message;
};
typedef struct Cmd_t Cmd;

//Linked list information
enum LLtype 
{
    llt_string,
    llt_frame,
    llt_integer,
    llt_head
} LLtype;

struct LLnode_t
{
    struct LLnode_t * prev;
    struct LLnode_t * next;
    enum LLtype type;

    void * value;
};
typedef struct LLnode_t LLnode;

#define MAX_FRAME_SIZE 64

//TODO: You should change this!
//Remember, your frame can be AT MOST 64 bytes!
#define FRAME_PAYLOAD_SIZE 58
#define HEAD_SIZE 8
struct Frame_t
{
    unsigned char sendId, recvId;
    unsigned char seqNum, ackNum;
    char flag;
    char data[FRAME_PAYLOAD_SIZE];
    unsigned char crc;
};
typedef struct Frame_t Frame;

//Receiver and sender data structures
struct Receiver_t
{
    //DO NOT CHANGE:
    // 1) buffer_mutex
    // 2) buffer_cv
    // 3) input_framelist_head
    // 4) recv_id
    pthread_mutex_t buffer_mutex;
    pthread_cond_t buffer_cv;
    LLnode * input_framelist_head;
    
    int recv_id;

    /* receiver side state: */
    unsigned char NFE; /* seqno of next frame expected */
    struct recvQ_slot {
        bool received; /* is msg valid? */
        Frame* msg;
    } recvQ[8];
};

struct Sender_t
{
    //DO NOT CHANGE:
    // 1) buffer_mutex
    // 2) buffer_cv
    // 3) input_cmdlist_head
    // 4) input_framelist_head
    // 5) send_id
    pthread_mutex_t buffer_mutex;
    pthread_cond_t buffer_cv;    
    LLnode * input_cmdlist_head;
    LLnode * input_framelist_head;
    int send_id;

    /* sender side state: */
    unsigned char LAR; /* seqno of last ACK received */
    unsigned char LFS; /* last frame sent */
    
    int seqCount; // sequence number counter
    int sendWindowNotFull;

    struct sendQ_slot {
        struct timeval* timeout; /* event associated with send-timeout */
        Frame* msg;
        int used;
    } sendQ[8];
};

enum SendFrame_DstType 
{
    ReceiverDst,
    SenderDst
} SendFrame_DstType ;

typedef struct Sender_t Sender;
typedef struct Receiver_t Receiver;

static bool swpInWindow(unsigned char seqno, unsigned char min,
                        unsigned char max)
{
    unsigned char pos, maxpos;
    pos = seqno - min;
    maxpos = max - min + 1;
    return pos < maxpos;
}

//Declare global variables here
//DO NOT CHANGE: 
//   1) glb_senders_array
//   2) glb_receivers_array
//   3) glb_senders_array_length
//   4) glb_receivers_array_length
//   5) glb_sysconfig
//   6) CORRUPTION_BITS
Sender * glb_senders_array;
Receiver * glb_receivers_array;
int glb_senders_array_length;
int glb_receivers_array_length;
SysConfig glb_sysconfig;
int CORRUPTION_BITS;
#endif