On Mon, Jul 29, 2013 at 2:02 PM, Artem S. Tashkinov <[email protected]> wrote: > Jul 29, 2013 11:43:00 PM, Eric wrote: > On Mon, 2013-07-29 at 15:47 +0000, Artem S. Tashkinov wrote: >> >>> A wine developer clearly showed that this option simply doesn't work. >>> >>> http://bugs.winehq.org/show_bug.cgi?id=26031#c21 >>> >>> Output of strace: >>> getsockopt(24, SOL_SOCKET, SO_REUSEADDR, [0], [4]) = 0 >>> setsockopt(24, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 >>> bind(24, {sa_family=AF_INET, sin_port=htons(43012), sin_addr=inet_addr("0. >>> 0.0.0")}, 16) = -1 EADDRINUSE (Address already in use) >> >>Its clear that some other socket did not use SO_REUSADDR >> >>All sockets using a given port _must_ have use SO_REUSADDR to allow this >>port being reused. >> > > It's exactly what's been tried. A program running with SO_REUSADDR, once no > longer > running consequently fails to regain the rights for the port.
To reiterate what Eric said, it seems likely that the listen socket on which the currently-open sockets were created did not have SO_REUSEADDR set. If you follow the sequence: a = socket() bind(a, 0.0.0.0, P) listen(a) accept(a) close(a) b = socket() setsockopt(b, SOL_SOCKET, SO_REUSEADDR, 1) bind(b, 0.0.0.0, P) this last bind() will fail. If you insert setsocket(a, SOL_SOCKET, SO_REUSEADDR, 1) before the first bind, (assuming all existing sockets on port P have timed out and entered the CLOSED state), this program will succeed. Put another way, when creating a listen socket, the creator has control over whether it's willing to allow any address reuse. This is strict -- if any existing connections exist, its bind will fail, and if any of its future connections exist, binds at that time will fail (regardless of whether that future socket has SO_REUSEADDR set). -John -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
