How can I try to read data from socket with timeout? I know, select, pselect, poll, has a timeout field, but using of them disables \"tcp fast-path\" in tcp reno stack.
Here's some simple code to add a time out to your recv
function using poll
in C:
struct pollfd fd;
int ret;
fd.fd = mySocket; // your socket handler
fd.events = POLLIN;
ret = poll(&fd, 1, 1000); // 1 second for timeout
switch (ret) {
case -1:
// Error
break;
case 0:
// Timeout
break;
default:
recv(mySocket,buf,sizeof(buf), 0); // get your data
break;
}
You can use the setsockopt function to set a timeout on receive operations:
SO_RCVTIMEO
Sets the timeout value that specifies the maximum amount of time an input function waits until it completes. It accepts a timeval structure with the number of seconds and microseconds specifying the limit on how long to wait for an input operation to complete. If a receive operation has blocked for this much time without receiving additional data, it shall return with a partial count or errno set to [EAGAIN] or [EWOULDBLOCK] if no data is received. The default for this option is zero, which indicates that a receive operation shall not time out. This option takes a timeval structure. Note that not all implementations allow this option to be set.
// LINUX
struct timeval tv;
tv.tv_sec = timeout_in_seconds;
tv.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);
// WINDOWS
DWORD timeout = timeout_in_seconds * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof timeout);
// MAC OS X (identical to Linux)
struct timeval tv;
tv.tv_sec = timeout_in_seconds;
tv.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);
Reportedly on Windows this should be done before calling bind
. I have verified by experiment that it can be done either before or after bind
on Linux and OS X.
// works also after bind operation for WINDOWS
DWORD timeout = timeout_in_seconds * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof timeout);
Install a handler for SIGALRM
, then use alarm()
or ualarm()
before a regular blocking recv()
. If the alarm goes off, the recv()
will return an error with errno
set to EINTR
.
LINUX
struct timeval tv;
tv.tv_sec = 30; // 30 Secs Timeout
tv.tv_usec = 0; // Not init'ing this can cause strange errors
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv,sizeof(struct timeval));
WINDOWS
DWORD timeout = SOCKET_READ_TIMEOUT_SEC * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout));
NOTE: You have put this setting before bind()
function call for proper run