我正在尝试使用下面的代码连接到UDP跟踪器服务器,但是我没有从跟踪器获得任何响应...
我从此链接中搜集了以下信息:http : //xbtt.sourceforge.net/udp_tracker_protocol.html
我以为我明白了……但显然没有。该代码执行正常,然后挂在对RecvFrom的调用上。所以我想我不是在发送正确的数据,还是在将其发送到错误的地方.....
struct ConnectionIdRequest_t {
uint64_t connectionId;
uint32_t action;
int32_t transactionId;
} typedef ConnectionIdRequest;
const bool UdpTorrentTrackerComm::initiateConnection(const int amountUploaded,
const int amountDownloaded,
const int amountLeft) {
struct sockaddr_in serverAddress, clientAddress;
struct hostent * host;
struct in_addr address;
//Setup dummy client address
clientAddress.sin_family = AF_INET;
clientAddress.sin_addr.s_addr = htonl(INADDR_ANY);
clientAddress.sin_port = htons(0);
//Setup server address
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(portNumber);
//SETUP in_addr server address
//If we have an IP
if (trackerAddress) {
if (isIp4Address(*trackerAddress)) {
//retrieve hostname from ip address
if (inet_aton(trackerAddress->c_str(), &address)) {
host = gethostbyaddr((const char *) &address, sizeof(address), AF_INET);
trackerHostname = new std::string(host->h_name);
}
else {
return false;
}
}
else {
return false;
}
}
else {
//retrieve ip address from hostname
host = gethostbyname(trackerHostname->c_str());
address.s_addr = ((struct in_addr *) host->h_addr_list)->s_addr;
trackerAddress = new std::string(inet_ntoa(address));
}
std::cout << *trackerAddress << std::endl;
//Convert trackerAddress to network format
if(!inet_aton(trackerAddress->c_str(), &serverAddress.sin_addr)) {
return false;
}
int sockFd = -1;
//Add IPv6 in the future
if ((sockFd = Socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
return false;
}
//Bind my address to the socket
if (Bind(sockFd, (struct sockaddr *) &clientAddress, sizeof(clientAddress)) == - 1) {
return false;
}
std::cout << "SendTo\n";
ConnectionIdRequest * idRequest = createConnectionIdRequest();
if (SendTo(sockFd, idRequest, sizeof(*idRequest), 0,
(struct sockaddr *) &serverAddress, sizeof(serverAddress)) == -1) {
return false;
}
timeRequestSent = clock();
std::cout << "Sent: " << idRequest->connectionId << "|||" << idRequest->action << "|||" << idRequest->transactionId << std::endl;
std::cout << "RecvFrom\n";
char buffer[3000];
socklen_t serverAddressLength = sizeof(serverAddress);
while(true) {
if (RecvFrom(sockFd, buffer, 3000, 0,
(struct sockaddr *) &serverAddress, &serverAddressLength) == - 1) {
break;
std::cout << "breaking...\n";
}
}
std::cout << "The buffer is: " << buffer << std::endl;
Close(sockFd);
return true;
}
ConnectionIdRequest * UdpTorrentTrackerComm::createConnectionIdRequest() {
ConnectionIdRequest * idRequest = new ConnectionIdRequest;
generatePeerId();
idRequest->connectionId = htonll(0x41727101980);
idRequest->action = htonl(CONNECT);
idRequest->transactionId = htonl(*peerId);
return idRequest;
}
编辑:好吧,我做了Arvid建议的一项更改,但这没有任何帮助。我正在检查并确保要转换的所有字节都按网络字节顺序转换...也许我丢失了某些东西...
我最终得到它的工作。问题主要是我没有将需要转换的所有值都转换为大端字节序(网络顺序),也没有使用过时的函数(gethostbyname等)。
如果您想了解更多详细信息,请发表评论。
这是对我建立与跟踪器服务器链接的代码:
注意:serverAddress和clientAddress是类型的类字段:struct sockaddr_in
const bool UdpTorrentTrackerComm::initiateConnection() {
//Setup dummy client address
clientAddress.sin_family = AF_INET;
clientAddress.sin_addr.s_addr = htonl(INADDR_ANY);
clientAddress.sin_port = htons(51413);
//Setup server address
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(portNumber);
//SETUP in_addr server address
//If we have an IP
if (trackerAddress) {
if (isIp4Address(*trackerAddress)) {
//Convert human readable trackerAddress to network byte order ip address and place in serverAddress.sin_addr
if (inet_pton(AF_INET, trackerAddress->c_str(), &(serverAddress.sin_addr))) {
//retrieve hostname and service type from ip address
char hostBuffer[100], serviceBuffer[100];
getnameinfo((struct sockaddr *) &serverAddress, sizeof(serverAddress),
hostBuffer, sizeof(hostBuffer),
serviceBuffer, sizeof(serviceBuffer),
NI_NAMEREQD | NI_DGRAM);
trackerHostname = new std::string(hostBuffer);
}
else {
return false;
}
}
else {
return false;
}
}
else {
//Setup structs to be used in getaddrinfo
struct addrinfo hints;
struct addrinfo * result, * resultPointer;
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = 0;
hints.ai_protocol = 0;
//Convert port number to string to pass to getaddrinfo
std::stringstream ss;
ss << portNumber;
std::string portNumberString = ss.str();
//retrieve ip address from hostname--------
if (GetAddrInfo(trackerHostname->c_str(), portNumberString.c_str(), &hints, &result) != 0) {
return false;
}
//Iterate over results for IP address V4 (ADD V6 later!)
char ipBuffer[INET_ADDRSTRLEN];
for (resultPointer = result; resultPointer != NULL; resultPointer = resultPointer->ai_next) {
//If we have an IPv4 address
if (resultPointer->ai_family == AF_INET) {
//convert to presentation format and store in ipBuffer
inet_ntop(AF_INET, &((struct sockaddr_in *) resultPointer->ai_addr)->sin_addr, ipBuffer, INET_ADDRSTRLEN);
}
}
//Free result
freeaddrinfo(result);
//Convert ipBuffer to std::string and store in trackerAddress field
trackerAddress = new std::string(ipBuffer);
//Convert trackerAddress to network format
if(!inet_pton(AF_INET, trackerAddress->c_str(), &serverAddress.sin_addr)) {
return false;
}
}
int sockFd = -1;
//Add IPv6 in the future
if ((sockFd = Socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
return false;
}
//Bind my address to the socket
if (Bind(sockFd, (struct sockaddr *) &clientAddress, sizeof(clientAddress)) == - 1) {
return false;
}
//Send a request to the tracker
ConnectionIdRequest * idRequest = createConnectionIdRequest();
if (SendTo(sockFd, idRequest, sizeof(*idRequest), 0,
(struct sockaddr *) &serverAddress, sizeof(serverAddress)) == -1) {
return false;
}
timeRequestSent = clock();
//Re-send until timeout.....
ConnectionIdResponse idResponse;
socklen_t serverAddressLength = sizeof(serverAddress);
while((timeRequestSent - clock()) / 1000 < SECONDS_UNTIL_TIMEOUT) {
//Response received!
if (RecvFrom(sockFd, &idResponse, sizeof(idResponse), 0,
(struct sockaddr *) &serverAddress, &serverAddressLength) > 0) {
break;
}
}
//Set class fields that will persist
activeSocket = sockFd;
connectionId = ntohll(idResponse.connectionId);
delete idRequest;
return true;
}
其中两个结构ConnectionIdResponse和ConnectionIdRequest定义为:
/* Struct used to send a request for a connectionId to the tracker server.*/
struct ConnectionIdRequest_t {
uint64_t connectionId;
uint32_t action;
uint32_t transactionId;
} typedef ConnectionIdRequest;
/* Struct used in receipt of a request for a connectionId from the tracker server. */
struct ConnectionIdResponse_t {
uint32_t action;
uint32_t transactionId;
uint64_t connectionId;
} typedef ConnectionIdResponse;
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我来说两句