Attachment 18060 Details for Bug 15451 – Patch for v4-18-test

[patch] Patch for v4-18-test

BZ15451-v4-18.patch (text/plain), 6.85 KB, created by Martin Schwenke on 2023-08-15 23:02:32 UTC

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Creator: Martin Schwenke

Created: 2023-08-15 23:02:32 UTC

Size: 6.85 KB

patch

obsolete

>From 3b2853e91056586dda1bb9ff313b09aebd55bc5d Mon Sep 17 00:00:00 2001
>From: Martin Schwenke <mschwenke@ddn.com>
>Date: Tue, 15 Aug 2023 10:43:57 +1000
>Subject: [PATCH 1/3] ctdb-common: Improve error handling
>
>Factor out a failure label, which will get more use in subsequent
>commits, and only set private_data when success is certain.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=15451
>
>Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
>Reviewed-by: Amitay Isaacs <amitay@gmail.com>
>(cherry picked from commit d87041d8968e91db9d257445321b85693303f95e)
>---
> ctdb/common/system_socket.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
>diff --git a/ctdb/common/system_socket.c b/ctdb/common/system_socket.c
>index 06dc558eb22..3a7b6eb41de 100644
>--- a/ctdb/common/system_socket.c
>+++ b/ctdb/common/system_socket.c
>@@ -988,7 +988,6 @@ int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
> 			errbuf);
> 		return -1;
> 	}
>-	*((pcap_t **)private_data) = pt;
> 
> 	pcap_packet_type = pcap_datalink(pt);
> 	switch (pcap_packet_type) {
>@@ -1005,8 +1004,7 @@ int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
> #endif /* DLT_LINUX_SLL2 */
> 	default:
> 		DBG_ERR("Unknown pcap packet type %d\n", pcap_packet_type);
>-		pcap_close(pt);
>-		return -1;
>+		goto fail;
> 	}
> 
> 	fd = pcap_get_selectable_fd(pt);
>@@ -1014,7 +1012,12 @@ int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
> 		  t,
> 		  fd);
> 
>+	*((pcap_t **)private_data) = pt;
> 	return fd;
>+
>+fail:
>+	pcap_close(pt);
>+	return -1;
> }
> 
> int ctdb_sys_close_capture_socket(void *private_data)
>-- 
>2.39.2
>
>
>From 4130971e9627f132c3581e207acdc1fb095a839d Mon Sep 17 00:00:00 2001
>From: Martin Schwenke <mschwenke@ddn.com>
>Date: Tue, 15 Aug 2023 10:57:59 +1000
>Subject: [PATCH 2/3] ctdb-common: Replace pcap_open_live() by lower level
> calls
>
>A subsequent commit will insert an additional call before
>pcap_activate().
>
>This sequence of calls is taken from the source for pcap_open_live(),
>so there should be no change in behaviour.
>
>Given the defaults set by pcap_create_common(), it would be possible
>to omit the calls to pcap_set_promisc() and pcap_set_timeout().
>However, those defaults don't seem to be well documented, so continue
>to explicitly set everything that was set before.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=15451
>
>Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
>Reviewed-by: Amitay Isaacs <amitay@gmail.com>
>(cherry picked from commit ffc2ae616d8fab7528fbdfd8c6b94c5b9a0e3a7c)
>---
> ctdb/common/system_socket.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
>diff --git a/ctdb/common/system_socket.c b/ctdb/common/system_socket.c
>index 3a7b6eb41de..16463af5a33 100644
>--- a/ctdb/common/system_socket.c
>+++ b/ctdb/common/system_socket.c
>@@ -980,14 +980,38 @@ int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
> 	int pcap_packet_type;
> 	const char *t = NULL;
> 	int fd;
>+	int ret;
> 
>-	pt = pcap_open_live(iface, 100, 0, 0, errbuf);
>+	pt = pcap_create(iface, errbuf);
> 	if (pt == NULL) {
> 		DBG_ERR("Failed to open pcap capture device %s (%s)\n",
> 			iface,
> 			errbuf);
> 		return -1;
> 	}
>+	/*
>+	 * pcap isn't very clear about defaults...
>+	 */
>+	ret = pcap_set_snaplen(pt, 100);
>+	if (ret < 0) {
>+		DBG_ERR("Failed to set snaplen for pcap capture\n");
>+		goto fail;
>+	}
>+	ret = pcap_set_promisc(pt, 0);
>+	if (ret < 0) {
>+		DBG_ERR("Failed to unset promiscuous mode for pcap capture\n");
>+		goto fail;
>+	}
>+	ret = pcap_set_timeout(pt, 0);
>+	if (ret < 0) {
>+		DBG_ERR("Failed to set timeout for pcap capture\n");
>+		goto fail;
>+	}
>+	ret = pcap_activate(pt);
>+	if (ret < 0) {
>+		DBG_ERR("Failed to activate pcap capture\n");
>+		goto fail;
>+	}
> 
> 	pcap_packet_type = pcap_datalink(pt);
> 	switch (pcap_packet_type) {
>-- 
>2.39.2
>
>
>From 265a31b9274b62743ab36d7569f7b15d0acc6fb2 Mon Sep 17 00:00:00 2001
>From: Martin Schwenke <mschwenke@ddn.com>
>Date: Tue, 15 Aug 2023 12:34:20 +1000
>Subject: [PATCH 3/3] ctdb-common: Set immediate mode for pcap capture
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>Fix a problem where ctdb_killtcp (almost always) fails to capture
>packets with --enable-pcap and libpcap â¥ 1.9.1.  The problem is due to
>a gradual change in libpcap semantics when using
>pcap_get_selectable_fd(3PCAP) to get a file descriptor and then using
>that file descriptor in non-blocking mode.
>
>pcap_set_immediate_mode(3PCAP) says:
>
>  pcap_set_immediate_mode() sets whether immediate mode should be set
>  on a capture handle when the handle is activated.  In immediate
>  mode, packets are always delivered as soon as they arrive, with no
>  buffering.
>
>and
>
>  On Linux, with previous releases of libpcap, capture devices are
>  always in immediate mode; however, in 1.5.0 and later, they are, by
>  default, not in immediate mode, so if pcap_set_immediate_mode() is
>  available, it should be used.
>
>However, it wasn't until libpcap commit
>2ade7676101366983bd4f86bc039ffd25da8c126 (before libpcap 1.9.1) that
>it became a requirement to use pcap_set_immediate_mode(), even with a
>timeout of 0.
>
>More explanation in this libpcap issue comment:
>
>  https://github.com/the-tcpdump-group/libpcap/issues/860#issuecomment-541204548
>
>Do a configure check for pcap_set_immediate_mode() even though it has
>existed for 10 years.  It is easy enough.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=15451
>
>Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
>Reviewed-by: Amitay Isaacs <amitay@gmail.com>
>
>Autobuild-User(master): Amitay Isaacs <amitay@samba.org>
>Autobuild-Date(master): Tue Aug 15 10:53:52 UTC 2023 on atb-devel-224
>
>(cherry picked from commit dc7b48c404337891b5105df4d6751cf549a533eb)
>---
> ctdb/common/system_socket.c | 7 +++++++
> ctdb/wscript                | 1 +
> 2 files changed, 8 insertions(+)
>
>diff --git a/ctdb/common/system_socket.c b/ctdb/common/system_socket.c
>index 16463af5a33..273b9c3400e 100644
>--- a/ctdb/common/system_socket.c
>+++ b/ctdb/common/system_socket.c
>@@ -1007,6 +1007,13 @@ int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
> 		DBG_ERR("Failed to set timeout for pcap capture\n");
> 		goto fail;
> 	}
>+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
>+	ret = pcap_set_immediate_mode(pt, 1);
>+	if (ret < 0) {
>+		DBG_ERR("Failed to set immediate mode for pcap capture\n");
>+		goto fail;
>+	}
>+#endif
> 	ret = pcap_activate(pt);
> 	if (ret < 0) {
> 		DBG_ERR("Failed to activate pcap capture\n");
>diff --git a/ctdb/wscript b/ctdb/wscript
>index 88e42439f5a..a7b04541014 100644
>--- a/ctdb/wscript
>+++ b/ctdb/wscript
>@@ -221,6 +221,7 @@ def configure(conf):
>         if not conf.CHECK_FUNCS_IN('pcap_open_live', 'pcap', headers='pcap.h'):
>             Logs.error('Need libpcap')
>             sys.exit(1)
>+        conf.CHECK_FUNCS_IN('pcap_set_immediate_mode', 'pcap', headers='pcap.h')
> 
>     if not conf.CHECK_FUNCS_IN('backtrace backtrace_symbols', 'execinfo',
>                                checklibc=True, headers='execinfo.h'):
>-- 
>2.39.2
>

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Attachments on bug 15451: 18059 | 18060 | 18061