From d4f2209cdb4dfda32f36fa750d97b7e1ba751a4d Mon Sep 17 00:00:00 2001 From: Antonio Quartulli Date: Sun, 14 Aug 2022 10:51:17 +0200 Subject: [PATCH] dco-win: ensure the DCO API is not used when running on Windows On Windows the high level API should still use the link_socket object to read and write packets. For this reason, even if dco_installed is true, we still need to rely on the classic link_socket object. Signed-off-by: Antonio Quartulli Acked-by: Lev Stipakov Message-Id: <20220814085117.7128-1-a@unstable.cc> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg24929.html Signed-off-by: Gert Doering --- src/openvpn/forward.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c index 14ad24fad..d70b4f52e 100644 --- a/src/openvpn/forward.c +++ b/src/openvpn/forward.c @@ -1593,6 +1593,26 @@ process_ip_header(struct context *c, unsigned int flags, struct buffer *buf) } } +/* Linux-like DCO implementations pass the socket to the kernel and + * disallow usage of it from userland, so (control) packets sent and + * received by OpenVPN need to go through the DCO interface. + * + * Windows DCO needs control packets to be sent via the normal + * standard Overlapped I/O. + * + * Hide that complexity (...especially if more platforms show up + * in future...) in a small inline function. + */ +static inline bool +should_use_dco_socket(struct link_socket *sock) +{ +#if defined(TARGET_LINUX) || defined(TARGET_FREEBSD) + return sock->info.dco_installed; +#else + return false; +#endif +} + /* * Input: c->c2.to_link */ @@ -1666,7 +1686,7 @@ process_outgoing_link(struct context *c) socks_preprocess_outgoing_link(c, &to_addr, &size_delta); /* Send packet */ - if (c->c2.link_socket->info.dco_installed) + if (should_use_dco_socket(c->c2.link_socket)) { size = dco_do_write(&c->c1.tuntap->dco, c->c2.tls_multi->peer_id, -- 2.47.2