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tcpFunc.h
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tcpFunc.h
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#ifndef TCPFUNC_H
#define TCPFUNC_H
#include <stdint.h>
#include <stdio.h>
#include <chrono>
#include <ctime>
#include <cstring>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <algorithm>
#include <iostream>
#define BUFFERSIZE 5240
#define HEADERSIZE 12
#define MSS 524
#define MAXSEQNUM 25600
#define RECV 1
#define SEND 0
#define PAYLOAD 512
#define RTO 10000
#define WaitCLS 2000
#define RET_TO 500
/* TODO change either cwnd or dest_port (won't use them at all) to indicate duplicate */
struct Header{
uint16_t dest_port;
uint16_t seqnum;
uint16_t acknum;
/*
FLAGS: ACK|FIN|SYN|PAD|PAD|PAD|PAD|PAD
*/
uint8_t flags;
uint16_t dup;
uint16_t len;
//char padding[1];
};
class Timer
{
public:
void start()
{
m_start = std::chrono::steady_clock::now();
m_running = true;
}
void stop()
{
m_end = std::chrono::steady_clock::now();
m_running = false;
}
double elapsed()
{
std::chrono::time_point<std::chrono::steady_clock> endTime;
if(m_running)
{
endTime = std::chrono::steady_clock::now();
}
else
{
endTime = m_end;
}
return std::chrono::duration_cast<std::chrono::milliseconds>(endTime - m_start).count();
}
private:
std::chrono::time_point<std::chrono::steady_clock> m_start;
std::chrono::time_point<std::chrono::steady_clock> m_end;
bool m_running = false;
};
class CongestionControl {
public:
CongestionControl(){
m_cwnd = cwnd_base;
m_ssthresh = ssthresh_base;
m_mode = 0;
}
void change_mode(int newmode){
m_mode = newmode;
}
void timeout(){
m_ssthresh = std::max((int)((float)m_cwnd/(float)2), ssthresh_base);
m_cwnd = cwnd_base;
change_mode(0);
}
void fast_retransmit_start(){
std::cout << "3 DUP ACK received, starting fast retransmit \n";
m_ssthresh = std::max((int)((float)m_cwnd/(float)2), ssthresh_base);
m_cwnd = m_ssthresh + 1536;
}
void fast_retransmit_end(){
std::cout << "All packets in range have been resent, entering CA\n";
m_cwnd = m_ssthresh;
m_mode = 1;
}
void fast_recovery(){
m_ssthresh = std::max((int)((float)m_cwnd/(float)2), ssthresh_base);
m_cwnd = m_ssthresh + 1536;
m_mode = 2;
}
int get_cwnd() const{
return m_cwnd/512 * 512;
}
int get_ssthresh() const{
return m_ssthresh;
}
int get_mode() const{
return m_mode;
}
void update(){
if (m_mode == 0){
if (m_cwnd < m_ssthresh){
m_cwnd += 512;
}
else{
change_mode(1);
m_cwnd += (512*512) / m_cwnd;
}
}
else if (m_mode == 1){
m_cwnd += (512*512) / m_cwnd;
}
else{
m_cwnd += 512;
}
if (m_cwnd > max_cwnd){
m_cwnd = max_cwnd;
}
}
private:
int m_cwnd;
int max_cwnd = 10240; // 20 * 512
int m_ssthresh;
int m_mode; // 0 for slow start, 1 for congestion avoidance, 2 for fast recovery
int ssthresh_base = 5120;
int cwnd_base = PAYLOAD;
};
class Packet {
public:
Packet(struct Header* in_h, char* in_payload){
memset(payload, 0, PAYLOAD);
memcpy(payload, in_payload, in_h->len);
this->header.dest_port = in_h->dest_port;
this->header.seqnum = in_h->seqnum;
this->header.acknum = in_h->acknum;
this->header.dup = in_h->dup;
this->header.flags = in_h->flags;
this->header.len = in_h->len;
}
bool valid_seq() const {
return (header.seqnum >= 0 && header.seqnum <= MAXSEQNUM);
}
bool valid_ack() const {
return (header.seqnum >= 0 && header.seqnum <= MAXSEQNUM);
}
int payload_len() const {
return header.len;
}
int packet_size() const {
return HEADERSIZE + header.len;
}
int h_seqnum() const {
return header.seqnum;
}
int h_acknum() const {
return header.acknum;
}
uint8_t h_flags() const{
return header.flags;
}
short h_dup() const {
return header.dup;
}
char* p_payload() {
return payload;
}
Header p_header() const {
return header;
}
void printPack() const {
std::cout<<header.seqnum<<' '<<header.len<<std::endl;
std::cout<<(int)header.flags<<std::endl;
}
private:
struct Header header;
char payload[PAYLOAD];
};
bool getACK(uint8_t flags);
bool getFIN(uint8_t flags);
bool getSYN(uint8_t flags);
void setACK(uint8_t* flags);
void setFIN(uint8_t* flags);
void setSYN(uint8_t* flags);
void resetFLAG(uint8_t* flags);
void initConn(struct Header*h);
int logging(int, struct Header*, int cwnd, int ssthresh);
bool seqnum_comp(Packet a, Packet b);
int cnct_server(int, char*, struct Header*, char*, struct sockaddr_in*, socklen_t*);
int cnct_client(int, char*, struct Header*, char*, struct sockaddr_in*, socklen_t*, int, CongestionControl);
int cls_init(int, char*, struct Header*, char*, struct sockaddr_in*, socklen_t*, uint16_t);
int cls_resp1(int, char*, struct Header*, char*, struct sockaddr_in*, uint16_t);
int cls_resp2(int, char*, struct Header*, char*, struct sockaddr_in*, uint16_t);
int wait_cls(int);
int readPacket(struct Header* h, char* payload, int l, char* packet);
int writePacket(struct Header* h, char* payload, int l, char* packet);
#endif