Hi all, While I read __tcp_select_window() code, I find that it maybe return a smaller window. Below is one scenario I thought, may be not right: In function __tcp_select_window(), assume: full_space is 6mss, free_space is 2mss, tp->rcv_wnd is 3MSS. And assume disable window scaling, then window = tp->rcv_wnd > free_space && window > free_space then it will round down free_space and return it.
Is this expected behavior? The comment is also saying "Get the largest window that is a nice multiple of mss." Should we do something like below ? Or I miss something? I don't know how to verify it now. --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2680,9 +2680,9 @@ u32 __tcp_select_window(struct sock *sk) * We also don't do any window rounding when the free space * is too small. */ - if (window <= free_space - mss || window > free_space) + if (window <= free_space - mss) window = rounddown(free_space, mss); - else if (mss == full_space && + else if (window <= free_space && mss == full_space && free_space > window + (full_space >> 1)) window = free_space; } Thanks.