How to clear socket buffer in linux?

by georgiana.senger , in category: General Help , a month ago

How to clear socket buffer in linux?

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1 answer

by emilia_hackett , a month ago

@georgiana.senger 

To clear the socket buffer in Linux, you can use the setsockopt system call with the SO_RCVBUF option. Here is an example code snippet in C:

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#include <sys/types.h>
#include <sys/socket.h>

int main() {
    int sockfd = /* your socket file descriptor */;
    
    int bufsize = 0;
    socklen_t optlen = sizeof(bufsize);
    
    // Get the current receive buffer size
    if (getsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &bufsize, &optlen) == -1) {
        perror("getsockopt");
        return 1;
    }
    
    printf("Current receive buffer size: %d
", bufsize);
    
    // Set the receive buffer size to zero
    bufsize = 0;
    if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &bufsize, optlen) == -1) {
        perror("setsockopt");
        return 1;
    }
    
    // Get the receive buffer size again to verify that it has been cleared
    if (getsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &bufsize, &optlen) == -1) {
        perror("getsockopt");
        return 1;
    }
    
    printf("Updated receive buffer size: %d
", bufsize);
    
    return 0;
}


You will need to replace /* your socket file descriptor */ with the appropriate socket file descriptor for the socket you want to clear the buffer.


Note that the actual buffer size may still be controlled by the kernel based on various factors, so setting the receive buffer size to zero may not completely clear the buffer.