SO_KEEPALIVE: Set on the server socket or on a per-client basis?

Question

I have the following function for configuring TCP Keepalive for a socket:

int configure_tcp_keepalive(int fd)
{
    int opt_val = 1;
    if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &opt_val, sizeof(opt_val)) == -1)
        return -1;

    int keepcnt = 9; //default value on Linux
    if (setsockopt(fd, SOL_TCP, TCP_KEEPCNT, &keepcnt, sizeof(keepcnt)) == -1) 
        return -1;

    int keepidle = 30;
    if (setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, &keepidle, sizeof(keepidle)) == -1) 
        return -1;

    int keepintvl = 30;
    if (setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, &keepintvl, sizeof(keepintvl)) == -1) 
        return -1;
}

If I call this function on the server fd, will it affect every accept()'d client (i.e. will accept()'d clients inherit these socket options and thus be configured for TCP Keepalive)? I'd rather not have to call this function for every client, in order to minimize overhead. Thanks.

score 0 · Answer 1 · answered Apr 16 '17 at 21:12

0

It looks like this should work. The book "Unix Network Programming" says:

answered Apr 16 '17 at 21:12

Barmar

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Thanks, I wonder if this applies to the other SO_KEEPALIVE options as well. I guess I'll have to check with Wireshark. – Hello Apr 16 '17 at 22:00
Probably. The book is pretty old, those options probably didn't exist at the time. Try it and see. – Barmar Apr 16 '17 at 22:02
Yup. They apply as well. – Hello Apr 16 '17 at 22:14

SO_KEEPALIVE: Set on the server socket or on a per-client basis?

1 Answers1