https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=ee2292413792f0360d357bc200c5e947eae516e6
commit ee2292413792f0360d357bc200c5e947eae516e6 Author: Corinna Vinschen <[email protected]> Date: Wed Jul 1 21:26:59 2020 +0200 Cygwin: tcp: Support TCP_QUICKACK Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/fhandler.h | 1 + winsup/cygwin/fhandler_socket_inet.cc | 45 +++++++++++++++++++++++++++++++++++ winsup/cygwin/include/netinet/tcp.h | 3 +++ 3 files changed, 49 insertions(+) diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h index 24184dacc..7a28adc16 100644 --- a/winsup/cygwin/fhandler.h +++ b/winsup/cygwin/fhandler.h @@ -719,6 +719,7 @@ class fhandler_socket_inet: public fhandler_socket_wsock { private: bool oobinline; /* True if option SO_OOBINLINE is set */ + bool tcp_quickack; /* True if quickack is enabled */ bool tcp_fastopen; /* True if TCP_FASTOPEN is set on older systems */ int tcp_keepidle; /* TCP_KEEPIDLE value in secs on older systems */ int tcp_keepcnt; /* TCP_KEEPCNT value on older systems */ diff --git a/winsup/cygwin/fhandler_socket_inet.cc b/winsup/cygwin/fhandler_socket_inet.cc index 6b6b63d83..74c415d60 100644 --- a/winsup/cygwin/fhandler_socket_inet.cc +++ b/winsup/cygwin/fhandler_socket_inet.cc @@ -693,6 +693,7 @@ fhandler_socket_wsock::set_socket_handle (SOCKET sock, int af, int type, fhandler_socket_inet::fhandler_socket_inet () : fhandler_socket_wsock (), oobinline (false), + tcp_quickack (false), tcp_fastopen (false), tcp_keepidle (7200), /* WinSock default */ tcp_keepcnt (10), /* WinSock default */ @@ -1579,6 +1580,10 @@ fhandler_socket_wsock::writev (const struct iovec *const iov, const int iovcnt, #define TCP_MAXRT 5 /* Older systems don't support TCP_MAXRTMS TCP_MAXRT takes secs, not msecs. */ +#ifndef SIO_TCP_SET_ACK_FREQUENCY +#define SIO_TCP_SET_ACK_FREQUENCY _WSAIOW(IOC_VENDOR,23) +#endif + #define MAX_TCP_KEEPIDLE 32767 #define MAX_TCP_KEEPCNT 255 #define MAX_TCP_KEEPINTVL 32767 @@ -1767,6 +1772,41 @@ fhandler_socket_inet::setsockopt (int level, int optname, const void *optval, ignore = true; break; + case TCP_QUICKACK: + /* Various sources on the net claim that TCP_QUICKACK is supported + by Windows, even using the same optname value of 12. However, + the ws2ipdef.h header calls this option TCP_CONGESTION_ALGORITHM + and there's no official statement, nor official documentation + confirming or denying this option is equivalent to Linux' + TCP_QUICKACK. Also, weirdly, this option takes values from 0..7. + + There is another undocumented option to WSAIoctl called + SIO_TCP_SET_ACK_FREQUENCY which is already used by some + projects, so we're going to use it here, too, for now. + + There's an open issue in the dotnet github, + https://github.com/dotnet/runtime/issues/798 + Hopefully this clarifies the situation in the not too distant + future... */ + { + DWORD dummy; + /* https://stackoverflow.com/questions/55034112/c-disable-delayed-ack-on-windows + claims that valid values for SIO_TCP_SET_ACK_FREQUENCY are + 1..255. In contrast to that, my own testing shows that + valid values are 0 and 1 exclusively. */ + int freq = !!*(int *) optval; + if (WSAIoctl (get_socket (), SIO_TCP_SET_ACK_FREQUENCY, &freq, + sizeof freq, NULL, 0, &dummy, NULL, NULL) + == SOCKET_ERROR) + { + set_winsock_errno (); + return -1; + } + ignore = true; + tcp_quickack = freq ? true : false; + } + break; + case TCP_MAXRT: /* Don't let this option slip through from user space. */ set_errno (EOPNOTSUPP); @@ -1983,6 +2023,11 @@ fhandler_socket_inet::getsockopt (int level, int optname, const void *optval, switch (optname) { + case TCP_QUICKACK: + *(int *) optval = tcp_quickack ? 1 : 0; + *optlen = sizeof (int); + return 0; + case TCP_MAXRT: /* Don't let this option slip through from user space. */ set_errno (EOPNOTSUPP); diff --git a/winsup/cygwin/include/netinet/tcp.h b/winsup/cygwin/include/netinet/tcp.h index 8ccb0dfaa..7e4f5bbd6 100644 --- a/winsup/cygwin/include/netinet/tcp.h +++ b/winsup/cygwin/include/netinet/tcp.h @@ -126,6 +126,9 @@ struct tcphdr { #define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ #define TCP_KEEPIDLE 0x03 /* start keepalives after this period */ #define TCP_MAXSEG 0x04 /* get maximum segment size (r/o on windows) */ +#define TCP_QUICKACK 0x0c /* block/reenable quick acks + (TCP_CONGESTION_ALGORITHM in ws2ipdef.h, + valid vals 0 - 7, unclear if equivalent) */ #define TCP_USER_TIMEOUT 0x0e /* how long for loss retry before timeout, like WinSock TCP_MAXRTMS/TCP_MAXRT */ #define TCP_FASTOPEN 0x0f /* enable FastOpen on listeners */
