From: Martin Schwenke <mschwenke@ddn.com>
Date: Tue, 15 Aug 2023 00:57:59 +0000 (+1000)
Subject: ctdb-common: Replace pcap_open_live() by lower level calls
X-Git-Tag: samba-4.17.11~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bb905f04b505369e805613e694c2cbb62bd91dee;p=thirdparty%2Fsamba.git

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)
---

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) {