backport drbd main ipv6: Fix interface indices larger than 255

drbd services occasionally fail at rapid successive swact
Netlink device number exceeding 255 (max number
that can be represented with two characters in hex ,
"ff") fail to parse by drbdadm during fast successive swacts,
the Netlink device number (second string in lines of
/proc/net/if_inet6]) gets very large exceeding 255 decimal and
cannot be represented as two hex characters (ff), like this:
fe80000000000000eceeeefffeeeeeee 14e 40 20 80 cali19a19189318

Closes-bug: 1877907

Change-Id: I035eb81830f3c5e5a129c20766348ff842bc05c8
Signed-off-by: Paul Vaduva <Paul.Vaduva@windriver.com>

filesystem/drbd/drbd-tools/centos/drbd.spec

@@ -44,6 +44,7 @@ Patch0006: 0006-avoid-kernel-userspace-version-check.patch
 Patch0007: 0007-Update-OCF-to-attempt-connect-in-certain-states.patch
 Patch0008: 0008-Increase-short-cmd-timeout-to-15-secs.patch
 Patch0009: 0009-Check-for-mounted-device-before-demoting-Primary-DRB.patch
+Patch0010: 0010-backport-drbd-main-ipv6-Fix-interface-indices-larger.patch
 
 License: GPLv2+
 ExclusiveOS: linux
@@ -273,6 +274,7 @@ management utility.
 %patch0007 -p1
 %patch0008 -p1
 %patch0009 -p1
+%patch0010 -p1
 
 %build
 %configure \

filesystem/drbd/drbd-tools/centos/patches/0010-backport-drbd-main-ipv6-Fix-interface-indices-larger.patch

@@ -0,0 +1,39 @@
+From 393137563853cde5561845aeb8498d831d6368aa Mon Sep 17 00:00:00 2001
+From: paul <paul@starlingx.com>
+Date: Mon, 29 Jun 2020 16:48:39 +0000
+Subject: [PATCH] backport: drbd main ipv6: Fix interface indices larger than
+ 255
+
+fscanf line probably copied from kernel printf, but printf specifies the
+minimal field width and scanf the maximal field width.
+
+The bug was triggered on Xen servers that create and assign new,
+incremented interface IDs for new machines.
+
+ifindex is of type int anyways: struct net_device as defined in
+include/linux/netdevice.h. We should not rely on the assumption that
+the values are small enough to fit in one byte.
+
+Signed-off-by: Roland Kammerer <roland.kammerer@linbit.com>
+
+Signed-off-by: paul <paul@starlingx.com>
+---
+ user/drbdadm_main.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/user/drbdadm_main.c b/user/drbdadm_main.c
+index 19c5a44..d516d6f 100644
+--- a/user/drbdadm_main.c
++++ b/user/drbdadm_main.c
+@@ -3091,7 +3091,7 @@ int have_ip_ipv6(const char *ip)
+ 
+ 	while (fscanf
+ 	       (if_inet6,
+-		X32(08) X32(08) X32(08) X32(08) " %*02x %*02x %*02x %*02x %s",
++		X32(08) X32(08) X32(08) X32(08) " %*x %*x %*x %*x %s",
+ 		b, b + 1, b + 2, b + 3, name) > 0) {
+ 		for (i = 0; i < 4; i++)
+ 			addr6.s6_addr32[i] = cpu_to_be32(b[i]);
+-- 
+1.8.3.1
+