C++ Reconnect TCP Server to Client after Client restart - c++

Question

I want to implement a 'flexible' TCP connection where I can randomly shutdown and restart both the Server and the Client. The other one should then automatically detect the shutdown and enter try to reconnect. I successfully implemented this s.t. I can shutdown and restart the server. The client discovers the shutdown (via recv(...) == 0) and then closes the connection (it therefore closes the sockets close(this->sockfd_) and close(this->newsockfd_)).
Unfortunately I am not able to get this working the other way around. I initialize the server (using the class constructor) the following way:
tcpServer::tcpServer(int _port) {
this->sockfd_ = -1;
this->port_ = _port;
this->connected_ = false;
if ((this->sockfd_ = socket(AF_INET, SOCK_STREAM, 0)) < 0)
this->dieWithError("ERROR opening Socket");
else
printf("-> Port %d: Socket opened\n", this->port_);
// get rid of "address already in use" error message
int yes = 1;
setsockopt(this->sockfd_, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
/* assign values to the fields of struct sockaddr_in */
bzero((char *) &this->serv_addr_, sizeof(this->serv_addr_));
this->serv_addr_.sin_family = AF_INET;
this->serv_addr_.sin_port = htons(this->port_);
this->serv_addr_.sin_addr.s_addr = INADDR_ANY;
/* bind the socket to an address */
if (bind(this->sockfd_, (struct sockaddr *) &this->serv_addr_, sizeof(this->serv_addr_)) < 0) {
printf("-> Port %d:", this->port_);
this->dieWithError("ERROR on binding");
}
printf("-> Binding successful. Start TCP client in new terminal\n");
fflush(stdout);
/* listen for connections and accept a connection */
listen(this->sockfd_, 5);
this->clilen_ = sizeof(this->cli_addr_);
if ((this->newsockfd_ = accept(this->sockfd_, (struct sockaddr *) &this->cli_addr_, &this->clilen_)) < 0)
this->dieWithError("Error on accept");
else {
printf("-> Connection established\n");
this->connected_ = true;
}
}
So once the server detects that the connection is closed, it enters a loop where it tries to reconnect using the following code:
void tcpServer::connect() {
if (this->sockfd_ == -1) {
/* create socket */
if ((this->sockfd_ = socket(AF_INET, SOCK_STREAM, 0)) < 0)
this->dieWithError("ERROR opening Socket");
else
printf("-> Port %d: Socket opened\n", this->port_);
// get rid of "address already in use" error message
int reuse_address = 1;
setsockopt(this->sockfd_, SOL_SOCKET, SO_REUSEADDR, &reuse_address, sizeof(int));
/* listen for connections and accept a connection */
listen(this->sockfd_, 5);
this->clilen_ = sizeof(this->cli_addr_);
if ((this->newsockfd_ = accept(this->sockfd_, (struct sockaddr *) &this->cli_addr_, &this->clilen_)) < 0)
this->dieWithError("Error on accept");
else {
printf("-> Connection established\n");
this->connected_ = true;
}
}
}
Some simple debugging output tells me that in the reconnect-mode, the server gets stuck in the
accept(this->sockfd_, (struct sockaddr *) &this->cli_addr_, &this->clilen_) call. Another observation I made is that the client does not shut down properly (via ctrl-c), i.e., it gets stuck in a loop somewhere and does not properly close the connection.
Since I am a total beginner with the TCP stuff, I would be very happy if someone could point me to the right direction. Thank you.