tracker.cpp

linux系统下bt的客户端实现。 采用的是c++

#include "Tracker.h"
#include <netdb.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include "Btcontent.h"
#include "Httpencode.h"

using namespace std;

const int INVALID_SOCK = -1;
const int T_CONNECTED = -1;
const int T_FREE = 0;
const int T_CONNECTING = 1;
const int T_READY = 2;
const int T_FINISHED = 3;

#define MAXHOSTNAMELEN    256
#define MAXPATHNAMELEN    1024
#define INFO_HASH_LEN    20

#ifndef DEBUG
#define DEBUG(fmt, ...) fprintf(stderr, fmt, __VA_ARGS__)  
#endif

btTracker TRACKER;

btTracker::btTracker()
{
	m_sock = INVALID_SOCK;
	m_listen_port = 6881;
	m_status = T_FREE;
	m_conn_refused = 0;
	m_peers_count = 0;
	m_seeds_count = 0;
	m_tracker_count = 0;
	m_tracker_active = 0;

	m_f_started = 0;
	m_f_stopped = 0;
	m_f_completed = 0;

	memset(m_tracker_id, 0, 21);
	for(int i = 0; i < 10; i++)
	{
		m_sock_list[i] = INVALID_SOCK;

		m_port_list[i] = 0;
		m_stat_list[i] = T_FREE;
		m_path_list[i] = NULL;
		m_host_list[i] = NULL;
	}

}

btTracker::~btTracker()
{
	//close(m_sock);
	char **p = m_host_list;
	for(; *p; p++)
		delete []*p;
		
	p = m_path_list;
	for(; *p; p++)
		delete[]*p;
}
void btTracker::CloseSocket(int idx)
{
	if(m_sock_list[idx] > 0)
		close(m_sock_list[idx]);
	m_sock_list[idx] = INVALID_SOCK;
    m_stat_list[idx] = T_CONNECTED; 
}

int btTracker::Reset()
{
}

int btTracker::Initial()
{
	char  **plist, *p, host[256], path[1024];
	int i = 0, port;


        plist = BTCONTENT.GetAnnounceList();
	for(; plist && *plist; plist++)
	{
		if (Http_url_analyse(*plist, host, (int *) &port, path) < 0
			|| (m_host_list[i] = new char [strlen(host) + 1]) == NULL
			|| (m_path_list[i] = new char [strlen(path) + 1]) == NULL)
		{
			delete [] m_host_list[i];
			delete [] m_path_list[i];
			m_port_list[i] = -1;
			continue;
		}

		strcpy(m_host_list[i], host);
		m_port_list[i] = port;
		strcpy(m_path_list[i], path);
			
		if(i++ == 8)
			break;
	}
	m_tracker_count = i;

	for(int i = 0; i < m_tracker_count; i++)
	{
		cout<<m_host_list[i]<<endl;
		cout<<m_path_list[i]<<endl;
        	cout<<m_port_list[i]<<endl;
	}

    
	char cnst[37] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	
	for (i = 0; i < 8; i++)
		m_key[i] = cnst[random() % 36];
	m_key[8] = '\0';

	return 0;

}

int btTracker::s2sin(char *host, int port, sockaddr_in * paddr)
{
	int n = 0;
	bzero(paddr, sizeof(struct sockaddr_in));

	port = htons(port);
	paddr->sin_family = AF_INET;
	paddr->sin_port = port;

	if (NULL == host)
		return -1;

	struct hostent *p;
	while(NULL == (p = gethostbyname(host)) && n++ < 5);
	if(NULL == p)
		return -1;
	paddr->sin_family = p->h_addrtype;
	memcpy(&(paddr->sin_addr), p->h_addr_list[0], sizeof(struct in_addr));

	return 0;
}

int btTracker::Connect(int i)
{
	struct sockaddr_in addr;
	int ret;

    printf("%s", "begin to connect...\n");
	printf("HOST:  %s\n",m_host_list[i]);
	printf("PORT:  %d\n",m_port_list[i]);

	bzero(&addr,sizeof(addr));
	
	if(s2sin(m_host_list[i], m_port_list[i], &addr) < 0 
		|| ((m_sock_list[i] = socket(AF_INET, SOCK_STREAM, 0)) < 0))
		return -2;
	printf("IP  :  %s\n",inet_ntoa(addr.sin_addr));		
	
	return  connect_nonb(m_sock_list[i],&addr, sizeof(addr));
}

int btTracker::SendRequest(int idx, int mode)
{
	char i_buff[3 * 20 + 1], p_buff[3 * 20 + 1], req_buffer[1024 * 2];
	char *path, *host, *format, *event, tempath[1024];
	char *pevent[] = { "started", "stopped", "completed" };
	size_t len;
	int port;

    path = m_path_list[idx];
	host = m_host_list[idx];
	port = m_port_list[idx];
	
    if(NULL == req_buffer || NULL == path || NULL == host || !port)
		return -1;

	if (!mode)
		event = pevent[0];
		
	if (strchr(path, '?'))
		format = REQ_URL_P1A_FMT;
	else
		format = REQ_URL_P1_FMT;
		
	if (snprintf(tempath, MAXPATHNAMELEN, format,
		(char *) path,
		Http_url_encode(i_buff, (char *) BTCONTENT.GetInfoHash(), 20), 
		Http_url_encode(p_buff,(char *) BTCONTENT.GetPeerId(),20),
		81,
		(char *) m_key) > MAXPATHNAMELEN)
		return -1;

	if (event) {
		if (snprintf(req_buffer, MAXPATHNAMELEN, REQ_URL_P2_FMT, 
					 tempath,
					 (unsigned long long) 0,
					 (unsigned long long) 0,
					 (unsigned long long) BTCONTENT.GetLeftBytes(), 
					 event, 100) > 1024)
			return -1;
	} 
	else 
	{
		if (snprintf(req_buffer, MAXPATHNAMELEN, REQ_URL_P3_FMT, 
					 tempath,
					 (unsigned long long) 0,
					 (unsigned long long) 0,
					 (unsigned long long) BTCONTENT.GetLeftBytes(), 
					 100) > 1024)
			return -1;
	}

	if (*m_tracker_id && MAXPATHNAMELEN - strlen(req_buffer)
		> 11 + strlen(m_tracker_id))
		strcat(strcat(req_buffer, "&trackerid="), m_tracker_id);

	struct sockaddr_in addr;
	if (Ip2sin(host, port, &addr) < 0)
	{
		char req_host[MAXHOSTNAMELEN];
		if (snprintf(req_host, MAXHOSTNAMELEN, 
				"\r\nHost: %s", host) > MAXHOSTNAMELEN)
			return -1;
		
		strcat(req_buffer, req_host);
	}

	strcat(req_buffer, "\r\nUser-Agent: ");
	strcat(req_buffer, "Bittorrent");
	strcat(req_buffer, "\r\nAccept: */*");
	strcat(req_buffer, "\r\nAccept-Encoding: gzip");
	strcat(req_buffer, "\r\nConnection: closed");

	strcat(req_buffer, "\r\n\r\n");
    cout<<req_buffer<<endl;

	if( (len = write(m_sock_list[idx], req_buffer, strlen(req_buffer)))
			> 0)
	{
	}

	return 0;

}

int btTracker::writen(int fd, const void *vptr, size_t len)
{
	size_t nleft;
	ssize_t nwrite;
	const char *ptr;

	ptr = (const char *) vptr;
	nleft = len;
	while (nleft) {
		if ( (nwrite = write(fd, vptr, len)) <= 0) {
			if (nwrite < 0 && errno == EINTR)
				nwrite = 0;
			else
				return -1;
		}

		nleft -= nwrite;
		ptr += nwrite;
	}
	return len;
}

int btTracker::readn(int fd, char* buffer, size_t len)
{
	size_t nread;
	int n;
	char* ptr;

    ptr = buffer;
	nread = 0;
	while(len)
	{
	 	if( (n = read(fd, ptr, len - n)) <= 0)
			if(n < 0 && errno == EINTR)
				continue;
			else
				break;
				
		nread += n;
		len -= n;
		ptr += n;
	}
}

int btTracker::Ip2sin(char *h, int p, struct sockaddr_in *psin)
{
	psin->sin_family = AF_INET;
	psin->sin_port = htons(p);
	psin->sin_addr.s_addr = inet_addr(h);
	return psin->sin_addr.s_addr == htonl(INADDR_NONE) ? -1 : 0;
}

//return if connected: 0, connecting : -1 , error : -2
int btTracker::connect_nonb(int sockfd, struct sockaddr_in *saptr,
							socklen_t salen)
{
	int flags, n;

	if ((flags = fcntl(sockfd, F_GETFL, 0) < 0) 
			|| fcntl(sockfd, F_SETFL, flags | O_NONBLOCK) < 0)
		return -2;

	if ((n = connect(sockfd, (struct sockaddr *) saptr, salen)) < 0)
	{
		if (errno == EINPROGRESS)
		{
			printf("%s\n","is connecting...");
			return -1;
		}
		else
		{
			printf("%s\n", "can not be connected");
			return -2;
		}
	}
	else
		return 0;
}

int btTracker::SocketReady(fd_set* rset, fd_set* wset, int* nfds, fd_set* next_rset, fd_set* next_wset)
{
	int i, n, ret, nactive = 0, maxfd = -1;
	char* buff[1024];
	
	  for(i = 0; i < m_tracker_count;)
	  {
			  
		DEBUG("Host : %s\n", m_host_list[i]);

		if(T_CONNECTED == m_stat_list[i])
				DEBUG("%s\n", "STATE : T_CONNECTED");
		else
		{
				if(INVALID_SOCK != m_sock_list[i] 
						&& FD_ISSET(m_sock_list[i], rset))
					DEBUG("%s\n", "read is set");
				if(INVALID_SOCK != m_sock_list[i] 
						&& FD_ISSET(m_sock_list[i], wset))