[arpwatch] fix devlookup to start when -i interface specified

[aledvink]

commit befc39955506cb319ba97f15eef6380e273ee4bb
Author: Ales Ledvinka <aledvink at redhat.com>
Date:   Mon Oct 15 16:15:49 2012 +0200

    fix devlookup to start when -i interface specified

 arpwatch-2.1a15-lookupiselect.patch |   98 +++++++++++++++++++++++++++++++++++
 arpwatch.spec                       |    7 ++-
 2 files changed, 104 insertions(+), 1 deletions(-)
---
diff --git a/arpwatch-2.1a15-lookupiselect.patch b/arpwatch-2.1a15-lookupiselect.patch
new file mode 100644
index 0000000..cc3a5bd
--- /dev/null
+++ b/arpwatch-2.1a15-lookupiselect.patch
@@ -0,0 +1,98 @@
+diff -up ./arpwatch.c.iselect ./arpwatch.c
+--- ./arpwatch.c.iselect	2012-10-15 16:01:24.701335291 +0200
++++ ./arpwatch.c	2012-10-15 16:07:18.626322639 +0200
+@@ -162,50 +162,52 @@ void dropprivileges(const char* user)
+ }
+ 
+ char *
+-get_first_dev(pcap_t **pd, int *linktype, char *errbuf)
++try_dev(char *interface, pcap_t **pd, int *linktype, char *errbuf)
+ {
+-	static char interface[IF_NAMESIZE + 1];
+ 	register int snaplen, timeout;
+-	pcap_if_t *alldevs;
+-	pcap_if_t *dev;
+-	char *ret = NULL;
+ 
+ 	snaplen = max(sizeof(struct ether_header),
+ 				  sizeof(struct fddi_header)) + sizeof(struct ether_arp);
+ 	timeout = 1000;
+ 
+-	if (pcap_findalldevs(&alldevs, errbuf) == -1) {
+-		(void)fprintf(stderr, "%s: lookup_device: %s\n",
+-					  prog, errbuf);
+-		exit(1);
++	*pd = pcap_open_live(interface, snaplen, 1, timeout, errbuf);
++	if (NULL == pd) {
++		syslog(LOG_ERR, "pcap open %s: %s", interface,  errbuf);
++		return NULL;
+ 	}
++	*linktype = pcap_datalink(*pd);
++	/* Must be ethernet or fddi */
++	if (*linktype != DLT_EN10MB && *linktype != DLT_FDDI) {
++		syslog(LOG_ERR, "(%s) Link layer type %d not ethernet or fddi",
++			   interface, *linktype);
++		pcap_close(*pd);
++		return NULL;
++	}
++	return interface;
++}
+ 
+-	for (dev = alldevs; dev; dev = dev->next) {
+-		strncpy(interface, dev->name, strlen(dev->name)+1);
+-
+-		*pd = pcap_open_live(interface, snaplen, 1, timeout, errbuf);
+-		if (*pd == NULL) {
+-			syslog(LOG_ERR, "pcap open %s: %s, trying next...", interface, errbuf);
+-			continue;
+-			/* exit(1); */
+-		}
++char *
++iterate_dev(char *arginterface, pcap_t **pd, int *linktype, char *errbuf)
++{
++	static char interface[IF_NAMESIZE + 1];
++	pcap_if_t *alldevs;
++	pcap_if_t *dev;
+ 
+-		*linktype = pcap_datalink(*pd);
+-		/* Must be ethernet or fddi */
+-		if (*linktype != DLT_EN10MB && *linktype != DLT_FDDI) {
+-			syslog(LOG_ERR, "(%s) Link layer type %d not ethernet or fddi, trying next...",
+-				   interface, *linktype);
+-			pcap_close(*pd);
++	if (NULL != arginterface) {
++		return try_dev(arginterface, pd, linktype, errbuf);
++	} else {
++		if (pcap_findalldevs(&alldevs, errbuf) == -1) {
++			(void)fprintf(stderr, "%s: lookup_device: %s\n",
++						  prog, errbuf);
++			exit(1);
+ 		}
+-		else {
+-			/* First match, use it */
+-			ret = interface;
+-			break;
++		for (dev = alldevs; dev && (arginterface == NULL); dev = dev->next) {
++			strncpy(interface, dev->name, strlen(dev->name)+1);
++			arginterface = try_dev(interface, pd, linktype, errbuf);
+ 		}
+-
++		pcap_freealldevs(alldevs);
++		return arginterface;
+ 	}
+-	pcap_freealldevs(alldevs);
+-	return (ret);
+ }
+ 
+ int
+@@ -315,8 +317,8 @@ main(int argc, char **argv)
+ 	} else {
+ 
+ 		/* Determine interface if not specified */
+-		if (interface == NULL &&
+-			(interface = get_first_dev(&pd, &linktype, errbuf)) == NULL) {
++		interface = iterate_dev(interface, &pd, &linktype, errbuf);
++		if (interface == NULL) {
+ 			(void)fprintf(stderr, "%s: lookup_device: no suitable interface found\n",
+ 						  prog);
+ 			exit(1);
diff --git a/arpwatch.spec b/arpwatch.spec
index 1fcc43d..285c8fe 100644
--- a/arpwatch.spec
+++ b/arpwatch.spec
@@ -3,7 +3,7 @@
 Name: arpwatch
 Epoch: 14
 Version: 2.1a15
-Release: 23%{?dist}
+Release: 24%{?dist}
 Summary: Network monitoring tools for tracking IP addresses on a network
 Group: Applications/System
 License: BSD with advertising
@@ -35,6 +35,7 @@ Patch10: arpwatch-2.1a15-extraman.patch
 Patch11: arpwatch-exitcode.patch
 Patch12: arpwatch-2.1a15-dropgroup.patch
 Patch13: arpwatch-2.1a15-devlookup.patch
+Patch14: arpwatch-2.1a15-lookupiselect.patch
 
 %description
 The arpwatch package contains arpwatch and arpsnmp.  Arpwatch and
@@ -62,6 +63,7 @@ network.
 %patch11 -p1 -b .exitcode
 %patch12 -p1 -b .dropgroup
 %patch13 -p1 -b .devlookup
+%patch14 -p1 -b .iselect
 
 %build
 %configure
@@ -139,6 +141,9 @@ fi
 %attr(-,arpwatch,arpwatch) %verify(not md5 size mtime) %config(noreplace) %{_vararpwatch}/ethercodes.dat
 
 %changelog
+* Mon Oct 15 2012 Ales Ledvinka <aledvink at redhat.com> - 14:2.1a15-24
+- fix devlookup to start with -i interface specified (#842660)
+
 * Wed Aug 22 2012 Jan Synáček <jsynacek at redhat.com> - 14:2.1a15-23
 - Add system-rpm macros (#850032)