--mtu-disc (on Linux) needs two components to work:
- setsockopt() with IP_MTU_DISCOVER or IPV6_MTU_DISCOVER
- "extended error reporting" (setsockopt(IP_RECVERR) and
then via mtu.c/format_extended_socket_error()) to react on
"packet too big" errors on sendto() / sendmsg()
Some configure.ac reorganization broke detection of <linux/errqueue.h>
and "struct sock_extended_err". Re-add <linux/errqueue.h> to configure.ac,
remove all the other conditionals in syshead.h, and remove the
"struct sock_extended_err" check completely (assumption: if errqueue.h
exists, it contains what we need).
Thus, the "non-helpful" socket error message turns into:
2022-02-22 12:31:42 write UDPv4 [EMSGSIZE Path-MTU=800]: Message too long
(fd=3,code=90)
2022-02-22 12:31:42 Note adjusting 'mssfix 1400 mtu' to 'mssfix 800 mtu'
according to path MTU discovery
2022-02-22 12:31:42 Note adjusting 'fragment 1400 mtu' to 'fragment 800 mtu'
according to path MTU discovery
... while at it, fix extra space in first part of these messages, and
print o->ce.fragment for the "fragment" message...
v2: assume that "if it's linux, and has these two headers, everything
else will be there as well" and get rid of most of the #ifdef checks
Trac: #1452
Signed-off-by: Gert Doering <g...@greenie.muc.de>
---
configure.ac | 8 +-------
src/openvpn/mss.c | 6 +++---
src/openvpn/syshead.h | 2 +-
3 files changed, 5 insertions(+), 11 deletions(-)
diff --git a/configure.ac b/configure.ac
index d42185d0..9c898718 100644
--- a/configure.ac
+++ b/configure.ac
@@ -425,7 +425,7 @@ AC_CHECK_HEADERS([ \
unistd.h libgen.h stropts.h \
syslog.h pwd.h grp.h termios.h \
sys/sockio.h sys/uio.h linux/sockios.h \
- linux/types.h poll.h sys/epoll.h err.h \
+ linux/types.h linux/errqueue.h poll.h sys/epoll.h err.h \
])
SOCKET_INCLUDES="
@@ -484,12 +484,6 @@ AC_CHECK_TYPE(
,
[[${SOCKET_INCLUDES}]]
)
-AC_CHECK_TYPE(
- [struct sock_extended_err],
- [AC_DEFINE([HAVE_SOCK_EXTENDED_ERR], [1], [struct sock_extended_err
needed for extended socket error support])],
- ,
- [[${SOCKET_INCLUDES}]]
-)
AC_CHECK_TYPE(
[struct msghdr],
[AC_DEFINE([HAVE_MSGHDR], [1], [struct msghdr needed for extended
socket error support])],
diff --git a/src/openvpn/mss.c b/src/openvpn/mss.c
index 81692e91..25b26405 100644
--- a/src/openvpn/mss.c
+++ b/src/openvpn/mss.c
@@ -361,7 +361,7 @@ frame_adjust_path_mtu(struct context *c)
|| (o->ce.mssfix_encap && pmtu < o->ce.mssfix + encap_overhead))
{
const char* mtustr = o->ce.mssfix_encap ? " mtu" : "";
- msg(D_MTU_INFO, "Note adjusting 'mssfix %d %s' to 'mssfix %d mtu' "
+ msg(D_MTU_INFO, "Note adjusting 'mssfix %d%s' to 'mssfix %d mtu' "
"according to path MTU discovery", o->ce.mssfix,
mtustr, pmtu);
o->ce.mssfix = pmtu;
@@ -374,8 +374,8 @@ frame_adjust_path_mtu(struct context *c)
(o->ce.fragment_encap && pmtu < o->ce.fragment + encap_overhead))
{
const char* mtustr = o->ce.fragment_encap ? " mtu" : "";
- msg(D_MTU_INFO, "Note adjusting 'fragment %d %s' to 'fragment %d mtu' "
- "according to path MTU discovery", o->ce.mssfix,
+ msg(D_MTU_INFO, "Note adjusting 'fragment %d%s' to 'fragment %d mtu' "
+ "according to path MTU discovery", o->ce.fragment,
mtustr, pmtu);
o->ce.fragment = pmtu;
o->ce.fragment_encap = true;
diff --git a/src/openvpn/syshead.h b/src/openvpn/syshead.h
index d699c608..a638b3dd 100644
--- a/src/openvpn/syshead.h
+++ b/src/openvpn/syshead.h
@@ -371,7 +371,7 @@ typedef int MIB_TCP_STATE;
/*
* Do we have the capability to report extended socket errors?
*/
-#if defined(HAVE_LINUX_TYPES_H) && defined(HAVE_LINUX_ERRQUEUE_H) &&
defined(HAVE_SOCK_EXTENDED_ERR) && defined(HAVE_MSGHDR) &&
defined(HAVE_CMSGHDR) && defined(CMSG_FIRSTHDR) && defined(CMSG_NXTHDR) &&
defined(IP_RECVERR) && defined(MSG_ERRQUEUE) && defined(SOL_IP)
+#if defined(HAVE_LINUX_TYPES_H) && defined(HAVE_LINUX_ERRQUEUE_H)
#define EXTENDED_SOCKET_ERROR_CAPABILITY 1
#else
#define EXTENDED_SOCKET_ERROR_CAPABILITY 0
--
2.26.3
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