tracker.cpp

linux系统下bt的客户端实现。 采用的是c++

					DEBUG("%s\n", "write is set");
		}
	
		if(T_FREE ==  m_stat_list[i])
		{
			DEBUG("%s\n", "state : T_FREE");
			
			ret = Connect(i);
			if(-2 == ret)
			{
				printf("\tHost: %s is not available\n", m_host_list[i]); 
				CloseSocket(i);
			}
			else if(ret == -1)
			{
				DEBUG("\t%s\n", "socket is being connected");
				m_stat_list[i] = T_CONNECTING;
				FD_SET(m_sock_list[i], next_rset);
				FD_SET(m_sock_list[i], next_wset);
			}
			else
			{
				if(0 == (ret = SendRequest(i, 0)))  //send
				{
					DEBUG("\t%s\n", "socket has been connected");
					m_stat_list[i] = T_READY;
					FD_SET(m_sock_list[i], next_rset);
				}
				else
				{
						close(m_sock_list[i]);
						m_stat_list[i] = T_FREE;
						continue;
						/*
						DEBUG("\tHost : %s  socket is being canceled\n", m_host_list[i]);
						CloseSocket(i);*/
				}
			}
		}
		else if(INVALID_SOCK != m_sock_list[i]  
				&& FD_ISSET(m_sock_list[i], wset) 
				&& m_stat_list[i] == T_CONNECTING)
		{
			int error;
			socklen_t len;

		    DEBUG("%s\n", "state : T_CONNECTING");
		
			len = sizeof(error);
		   	FD_CLR(m_sock_list[i], wset);
			if(FD_ISSET(m_sock_list[i], rset))
			{
				FD_CLR(m_sock_list[i], rset);
				(*nfds)--;
			}
			(*nfds)--;
			if(getsockopt(m_sock_list[i], SOL_SOCKET, SO_ERROR, &error, &len)< 0
					|| error != 0)
			{
				DEBUG("\t%s\n", "error is occured");
				CloseSocket(i);
			
			}
			else if(0 == SendRequest(i, 0)) //send immediately
			{
				DEBUG("\t%s\n", "request has been sent out");
				FD_SET(m_sock_list[i], next_rset);
				m_stat_list[i] = T_READY;
			}
			else
			{
					close(m_sock_list[i]);
					m_stat_list[i] = T_FREE;
					continue;
					/*
					DEBUG("\t%s\n", "has been disconnected");
					CloseSocket(i);*/
			}
		}
		else if(INVALID_SOCK != m_sock_list[i]  
				&& m_stat_list[i] == T_READY && FD_ISSET(m_sock_list[i], rset))
		{
			int error;
			socklen_t len;
			
			len = sizeof(error);
			(*nfds)--;
			FD_CLR(m_sock_list[i], rset);

			DEBUG("%s\n", "state : T_READY");
			
			if(getsockopt(m_sock_list[i], SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error != 0)
			{
					DEBUG("\t%s\n", "error is occured\n");
					CloseSocket(i);
			}
			else
			{
					
					if(-1 ==(n = CheckResponse(i)))  //need reconnect
					{
							DEBUG("\t%s\n", "has been redirected");
							m_stat_list[i] = T_FREE;
							close(m_sock_list[i]);
							continue;
					}
					else if(0 == n)  //read successfully
					{
							DEBUG("\t%s\n", "read successfully");
							FD_SET(m_sock_list[i], next_rset);
					}
					else
					{
							DEBUG("\t%s\n", "has been closed");
							CloseSocket(i);
					}
			}
		}
		else if(T_CONNECTED != m_stat_list[i] 
				&&(FD_ISSET(m_sock_list[i], rset) || FD_ISSET(m_sock_list[i], wset)))
		{
				DEBUG("%s\n", "state : abnormal");
				CloseSocket(i); // abnormally close socket
		}
		
		

		if(T_CONNECTED != m_stat_list[i])
		{
			nactive++;
	    	maxfd = (m_sock_list[i] > maxfd) ? m_sock_list[i] : maxfd;
		}
		
		i++;
		cout << endl << endl;
	}

	for(i = 0; i < m_tracker_count; i++)
	{
		if(m_stat_list[i] != T_CONNECTED)
			cout << "socket is read && write"<<endl;
		else
			cout<< "socket has been cancled"<<endl;
	
	}

	cout<<"active: "<<nactive<<endl;
	return nactive ? maxfd : -1; 
}

int btTracker::CheckResponse(int idx)
{
	char read_buffer[MAXPATHNAMELEN], *pdata, *p;
	int r;
	size_t dlen, hlen;

	r = read(m_sock_list[idx], read_buffer, 1023);

	if(r <= 0)
			return -2;
			
	read_buffer[r] = '\0';

	hlen = Http_split(read_buffer, r, &pdata, &dlen);

	if (hlen <= 0)
		return -2;

	r = Http_reponse_code(read_buffer, hlen);
	if (r <= 0)
		return -2;
	else if (r != 200) {
		if (r == 301 || r == 302) {
			char redirect[MAXHOSTNAMELEN];
			if (Http_get_header(read_buffer, hlen, 
					"Location", redirect) < 0)
			{
				DEBUG("%s\n", "get http header error!");
				return -2;
			}

			if (Http_url_analyse(redirect, m_host, (int*)&m_port, m_path)
				< 0)
			{
				DEBUG("%s\n", "analyze the url error!");
				return -2;
			}

			delete [] m_host_list[idx];
			delete [] m_path_list[idx];


			if(NULL != (p = strchr(m_path, '?')))
				*p++ = '\0';
			if(NULL == (m_host_list[idx] = new char [strlen(m_host) + 1])
					|| NULL == (m_path_list[idx] = new char[strlen(m_path) + 1]))
					delete [] m_host_list[idx];

			strcpy(m_host_list[idx], m_host);
			strcpy(m_path_list[idx], m_path);
			m_port_list[idx] = m_port;

			printf("%s\n", m_host_list[idx]);
			printf("%s\n", m_path_list[idx]);
			printf("%d\n", m_port_list[idx]);
			return -1;
		}
		else if (r >= 400)
		{
			DEBUG("%s\n", "the file has been deleted or removed");
			return -2;
		}
	}

	return UpdatePeerList(pdata, dlen) == -1 ? -2 : 0;
}

int btTracker::UpdatePeerList(char* buffer, size_t len)
{
	BencodeDict* pdict = NULL;
	Bencode* pcode;
	std::string keylist;
	char *p = NULL;
	int n, ret = -1;

	if((NULL == (pdict = new BencodeDict)) || !(pdict->Decode(buffer, len  + 1)))
	{
			DEBUG("%s\n", "Create dictionary error!\n");
			delete pdict;
			return -1;
	}
	
	keylist = "failure reason";
	if(search_dictionary(pdict, keylist, &p, NULL))
	{
		DEBUG("错误  : %s\n", p);
		delete []p;
		return -1;
	}
	
	keylist = "warning message";
	if(search_dictionary(pdict, keylist, &p, NULL))
	{
		DEBUG("警告  : %s\n", p);
		delete []p;
	}

	keylist = "tracker id";
	if(search_dictionary(pdict, keylist, &p, NULL))
	{
			if(strlen(p) == 20)
				memcpy(m_tracker_id, p, 20);
			delete []p;
	}

	keylist = "interval";
	if(search_dictionary(pdict, keylist, NULL, &n))
		m_conn_interval = n;

	keylist = "done peers";
	if(search_dictionary(pdict, keylist, NULL, &n))
		m_seeds_count = n;
	
	keylist = "complete";
	if(search_dictionary(pdict, keylist, NULL, &n))
		m_seeds_count = n;

	keylist = "incomplete";
	if(search_dictionary(pdict, keylist, NULL, &n))
		m_peers_count = m_seeds_count + n;
		
	keylist = "num peers";
	if(search_dictionary(pdict, keylist, NULL, &n))
		m_peers_count = n;
		
	keylist = "peers";
	if( NULL == (pcode = query_dict(pdict, keylist)) || GetPeerInfo(pcode) <= 0)
			return -1;

	delete_dictionary(pdict);
	return ret;
}


int btTracker::GetPeerInfo(Bencode* p)
{
		printf("begining to analyze peers\n");
		int n = 0;
		if(bencode_str == p->m_enumType) //compact mode
		{
				const char* dt;
				struct in_addr adr;
				n = ((BencodeString*)p)->m_strValue.length();
				if(0 != (n % 6))
						return -1;
				n = n / 6;
				printf("peer number is : %d\n", n);
				dt = ((BencodeString*)p)->m_strValue.data();

				int fd = open("txt", O_RDWR);
				write(fd, dt, ((BencodeString*)p)->m_strValue.length());
				
				for(int i = 0; i < n; i++)
				{
						unsigned char ip[4];
						unsigned short port;
						
						memcpy(&ip, dt, 4);
						dt += 4;

						memcpy(&port, dt, 2);
						dt +=2;
						port = ntohs(port);

		                printf("%u.%u.%u.%u\n", ip[0],ip[1],ip[2],ip[3]);
						printf("peer port : %d\n", port);
				}
				return n;
		}
		else if(bencode_list == p->m_enumType) //normal mode
		{
				vector<Bencode*>::iterator iter, iter_end;
				iter = ((BencodeList*)p)->m_list.begin();
				iter_end =((BencodeList*)p)->m_list.end();

				for(; iter != iter_end; iter++)
				{
						char*ip;
						int port;
						string keylist;
						BencodeDict* pdict;
						pdict =(BencodeDict*) (*iter);

						if(search_dictionary(pdict, keylist, &ip, NULL))
						{
								printf("peer ip : %s\n", ip);
								delete [] ip;
						}

						if(search_dictionary(pdict, keylist, NULL, &port))
						{
								printf("peer port : %d\n", port);
						}
						n++;
						
				}
		}

		return n;
}