aoetools/debian/patches/for-upstream/0001-aoe-sancheck-Refine-interface-probing.patch

From 4a3ee184e6e76aead8e55c412be3c9c924e76e24 Mon Sep 17 00:00:00 2001
From: Christoph Biedl <debian.axhn@manchmal.in-ulm.de>
Date: Sat, 22 May 2021 14:37:25 +0200
Subject: [PATCH 1/2] aoe-sancheck: Refine interface probing

There are two issues in the ethlist function in aoe-sancheck.c:

First it skips all network interfaces that do not start with "eth". This
is a problem these days where people use different naming schemes like the
so-called predictable interface names as mandated by udev/systemd.

Second it only probes for interfaces with an interface number of up
to 15. At least in current Linux, that number can take huge values and
those interfaces will be ignored completely.

About the first: Probe all interfaces (but lo) that support the ARP
protocol, assuming that is a fair indicator for ethernet support.

About the second, use the if_nameindex function to get a list of all
interfaces currently known to the kernel and operate on that one.
---
 aoe-sancheck.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

--- a/aoe-sancheck.c
+++ b/aoe-sancheck.c
@@ -501,23 +501,38 @@
 int
 ethlist(char **ifs, int nifs)
 {
-	int i, s, n;
+	int s, n;
 	struct ifreq ifr;
+	struct if_nameindex *if_ni, *i;
 
 	s = socket(AF_INET, SOCK_STREAM, 0);
 	if (s < 0)
 		return 0;
+
+	if_ni = if_nameindex();
+	if (if_ni == NULL)
+		return 0;
+
 	n = 0;
-	for (i=0; i<nifs; i++) {
+	for (i = if_ni; ! (i->if_index == 0 && i->if_name == NULL); i++) {
 		memset(&ifr, 0, sizeof ifr);
-		ifr.ifr_ifindex = i;
-		if (ioctl(s, SIOCGIFNAME, &ifr) < 0)
+		ifr.ifr_ifindex = i->if_index;
+		strcpy(ifr.ifr_name, i->if_name);
+		// get interface flags
+		if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0)
+			continue;
+		// only use interfaces that use arp protocol
+		if (ifr.ifr_flags & IFF_NOARP)
 			continue;
-		if (strncmp(ifr.ifr_name, "eth", 3))
+		// skip loopback interfaces
+		if (ifr.ifr_flags & IFF_LOOPBACK)
 			continue;
+		if (n == nifs)
+			break;
 		inserteth(ifs, nifs, ifr.ifr_name);
 		n++;
 	}
+	if_freenameindex(if_ni);
 	close(s);
 	return n;
 }