Subject: getsockopt(TCP_DEFER_ACCEPT) value change

From: Daniel Lezcano <[email-masked]>
Date: Tue, 05 Jan 2010 11:42:53 +0100

Hi,

I noticed a change in the value returned by the getsockopt for the 
TCP_DEFER_ACCEPT option with a 2.6.32 kernel. The value retrieved with 
the getsockopt is different from the one specified with the setsockopt. 
Is it an expected behaviour ?

I saw there were  changes around the TCP_DEFER_ACCEPT option with the 
number of attempts converted to a number of seconds.

The following program is working fine with a 2.6.31 but fails with a 
2.6.32 kernel.

Thanks
  -- Daniel

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>

int main(int argc, char *argv[])
{
    int val1 = 12, val2;
    socklen_t len = sizeof(val2);
    int fd;
   
    fd = socket(PF_INET, SOCK_STREAM, 0);
    if (fd < 0) {
        perror("socket");
        return -1;
    }
   
    if (setsockopt(fd, SOL_TCP, TCP_DEFER_ACCEPT, &val1, sizeof(val1))) {
        perror("setsockopt");
        return -1;
    }
   
    if (getsockopt(fd, SOL_TCP, TCP_DEFER_ACCEPT, &val2, &len)) {
        perror("getsockopt");
        return -1;
    }

    if (val1 != val2) {
        fprintf(stderr, "error %d != %d\n", val1, val2);
        return -1;
    }

    return 0;
}