HTTPS proxy never manages to connect successfully - c++

Question

What I'm trying to do is a forking proxy that deals HTTP(S) connections: while GET (without SSL) requests are successfully executed and the contents are delivered to the client, when it comes to CONNECT method things are not going well, since connect()ing to the remote server may not immediately succeeds: in fact, it nevers succeeds.
I tried for a non blocking socket connected to the remote server, so I can see if connect() goes immediately or takes some time: in the second case, I'd call select() to see when the remote server is ready to send data to me: yet, connect() never connects.
Here's my proxy main() code:
int main(int argc, char *argv[]) {
// ClientManager.cpp is described below
ClientManager cm;
//listening on port given by argv
if (cm.startListeningForClient(listening_port)) {
while(true) {
int new_client_socket = cm.acceptConnectionFromClient();
if (new_client_socket >= 0) {
cm.forkAndManageClient();
}
else {
perror("accept error");
}
}
} else {
perror("Error on start listening");
}
return EXIT_SUCCESS;
}
Now follows, with some omissis not involved with my issue, ClientManager.cpp, whose functions are called in main() above:
ClientManager::ClientManager() {
sockfd_client = -1; // socket connected to client
new_sockfd_client = -1; // socket accepting connection from client
sockfd_server = -1; // socket connected to remote server
}
// error controls omitted
bool ClientManager::startListeningForClient(int port) {
struct sockaddr_in serv_addr;
bzero((char*)&serv_addr,sizeof(serv_addr));
serv_addr.sin_family=AF_INET;
serv_addr.sin_port=htons(port);
serv_addr.sin_addr.s_addr=INADDR_ANY;
sockfd_client = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
bind(sockfd_client,(struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(sockfd_client, 50);
return true;
}
// error controls omitted
int ClientManager::acceptConnectionFromClient(void) {
struct sockaddr_in cli_addr;
unsigned int clilen;
bzero((char*)&cli_addr, sizeof(cli_addr));
clilen = sizeof(cli_addr);
new_sockfd_client = accept(sockfd_client, (struct sockaddr*)&cli_addr, &clilen);
return new_sockfd_client;
}
int ClientManager::forkAndManageClient() {
// getRequestFromClient: the method below receives requests from
// clients and parses the infos I need (i.e. what method,
// hostname of remote server to be resolved, its port, ...)
getRequestFromClient();
// managing the HTTP(S) request by the child process
int pid = fork();
if (pid < 0) {
perror("ERROR on fork");
}
else if (pid > 0) {
// parent process
// do nothing
}
else {
// close immediately the client socket used for accepting new connections from the parent process
close (sockfd_client);
if (!manageRequest()) {
perror("Error managing request from client");
}
// close the connection from the client
close (new_sockfd_client);
new_sockfd_client = -1;
// the child process will terminate now
_exit(EXIT_SUCCESS);
}
return pid;
}
// now the problematic method...
bool ClientManager::manageRequest(void) {
// if this is a CONNECT request
if (rm.isCONNECT()) {
struct sockaddr_in remote_server;
int conn_res;
remote_server.sin_family = AF_INET;
remote_server.sin_addr.s_addr = rm.getServerAddr();
remote_server.sin_port = rm.getServerPort();
fd_set fdset;
struct timeval tv;
sockfd_server = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// make socket not blocking
int flags = fcntl(sockfd_server, F_GETFL, 0);
flags = flags | O_NONBLOCK;
if (fcntl(sockfd_server, F_SETFL, flags) == -1) {
perror("FCNTL:");
}
printf("CONNECT set socket to non-blocking mode\n");
conn_res = connect(sockfd_server, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in));
printf("AFTER CONNECT()\n");
if (conn_res < 0) {
if (errno != EINPROGRESS) {
printf("CONNECT: connect() failed, quitting\n");
return false;
}
}
printf("CONNECT connection is taking place...\n");
// connected immediately
if (conn_res == 0) {
printf("CONNECT connected OK!\n");
goto CONNECTED;
}
FD_ZERO(&fdset);
FD_SET(sockfd_server, &fdset);
tv.tv_sec = 5; // tried 5, 20, 60 seconds, but it always times out
tv.tv_usec = 0;
printf("CONNECT attempting select()\n");
if (select(sockfd_server+1, NULL, &fdset, NULL, &tv) == 0) {
errno = ETIMEDOUT;
close(sockfd_server);
sockfd_server = -1;
return false;
}
if (FD_ISSET(sockfd_server, &fdset)) {
int so_error;
socklen_t len = sizeof so_error;
if (getsockopt(sockfd_server, SOL_SOCKET, SO_ERROR, &so_error, &len) < 0) {
return false;
}
} else {
printf("sockfd_server not set\n");
}
CONNECTED:
fcntl(sockfd_server, F_SETFL, flags &~ O_NONBLOCK);
// yeah, now I will start to deal the HTTPS flow in both directions
return true;
}
}
It does manage setting socket to non blocking mode, and to print CONNECT connection is taking place..., but it always returns Error managing request from client: Connection timed out.
I apologize for posting miles of LOC, but this is what drives me crazy since days, and after reading posts, tutorial and guides, I really don't know what to do.

Answer 1

It connects now to every site which requires an HTTPS connection!
Proper error checking and following closing of socket descriptors were missing. Here's my code:
bool ClientManager::manageRequest(void) {
if (rm.isCONNECT()) {
struct sockaddr_in remote_server, local_bind;
int conn_res, select_res;
memset(&remote_server, 0, sizeof(remote_server));
remote_server.sin_family = AF_INET;
remote_server.sin_addr.s_addr = rm.getServerAddr();
remote_server.sin_port = rm.getServerPort();
memset(&local_bind, 0, sizeof(local_bind));
local_bind.sin_family = AF_INET;
local_bind.sin_addr.s_addr = htonl(INADDR_ANY);
local_bind.sin_port = htons(0);
fd_set rdset, wrset;
struct timeval tv;
sockfd_server = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sockfd_server < 0) {
perror("socket: ");
}
if(!setNonBlocking(sockfd_server))
perror("fcntl");
debug_green("CONNECT set socket to non-blocking mode\n");
bind(sockfd_server, (struct sockaddr*) &local_bind, sizeof(local_bind));
conn_res = connect(sockfd_server, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in));
// The socket is nonblocking and the connection cannot be completed immediately
// check for EINPROGRESS
if ((conn_res == -1) && (errno != EINPROGRESS)) {
FD_ZERO(&rdset);
FD_SET(sockfd_server, &rdset);
wrset = rdset;
tv.tv_sec = 0;
tv.tv_usec = 0;
debug_yellow("CONNECT attempting select()\n");
do {
select_res = select(sockfd_server+1, &rdset, &wrset, NULL, &tv);
} while ((select_res == -1) && (errno == EINTR));
if ((!FD_ISSET(sockfd_server, &rdset)) && ((!FD_ISSET(sockfd_server, &wrset)))) {
debug_red("SELECT sockfds not responding\n");
close(sockfd_server);
sockfd_server = -1;
return false;
}
conn_res = connect(sockfd_server, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in));
if (conn_res == -1) {
if(errno == EISCONN)
printf ("connect(): connections already existing, OK\n");
else {
printf("connect() for safety check: connection NOT successfull\n");
close(sockfd_server);
sockfd_server = -1;
return false;
}
}
printf("connection OK\n");
fflush(stdout);
} else {
debug_green("Connection immediately OK\n");
fflush(stdout);
}
if (!setBlocking(sockfd_server)) {
perror("FCNTL:");
}
debug_green("CONNECT set socket back to blocking mode\n");fflush(stdout);
}
return true;
}
Functions setting blocking or non blocking socket:
bool ClientManager::setNonBlocking(int sockfd) {
printf("setting non block socket\n"); fflush(stdout);
int flags;
if ((flags = fcntl(sockfd, F_GETFL, 0)) < 0)
return false;
flags |= O_NONBLOCK;
if (fcntl(sockfd, F_SETFL, flags) < 0)
return false;
return true;
}
bool ClientManager::setBlocking(int sockfd) {
printf("setting block socket\n"); fflush(stdout);
int flags;
if ((flags = fcntl(sockfd, F_GETFL, 0)) < 0)
return false;
flags &= (~O_NONBLOCK);
if (fcntl(sockfd, F_SETFL, flags) < 0)
return false;
return true;
}
Debug functions:
#define DEFAULTCOLOR "\033[0m"
#define RED "\033[22;31m"
#define YELLOW "\033[1;33m"
#define GREEN "\033[0;0;32m"
#define debug_red(...) std::cout << RED << __VA_ARGS__ << DEFAULTCOLOR; fflush(stdout);
#define debug_yellow(...) std::cout << YELLOW << __VA_ARGS__ << DEFAULTCOLOR; fflush(stdout);
#define debug_green(...) std::cout << GREEN << __VA_ARGS__ << DEFAULTCOLOR; fflush(stdout);