[LTP] [PATCH v2 1/3] tst_net.sh: Fix for disabled IPv6

[Petr Vorel]

Tests failed in tst_init_iface even IPv4 only test was run.
Allow to init interfaces at least for IPv4.

We need IPv6 enabled on both endpoints to be usable,
unless test use TST_NET_SKIP_VARIABLE_INIT=1, i.e. use network library
functions but no test links (atm just library test tst_ipaddr_un.sh,
but netns_helper.sh will also use it). In this case only IPv6 on lhost
is tested.

Tests which use TST_IPV6=6 to force IPv6 (atm just broken_ip-nexthdr.sh)
need to be fixed, unless they use just tst_ipaddr_un() (e.g. library
test tst_ipaddr_un.sh).

Store result into $TST_NET_IPV6_ENABLED.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
 testcases/lib/tst_net.sh | 71 +++++++++++++++++++++++++++++++++-------
 1 file changed, 60 insertions(+), 11 deletions(-)

diff --git a/testcases/lib/tst_net.sh b/testcases/lib/tst_net.sh
index 047686dc39..15fd595942 100644
--- a/testcases/lib/tst_net.sh
+++ b/testcases/lib/tst_net.sh
@@ -24,7 +24,9 @@ TST_IPV6_FLAG=${TST_IPV6_FLAG:-}
 tst_net_parse_args()
 {
 	case $1 in
-	6) TST_IPV6=6 TST_IPVER=6 TST_IPV6_FLAG="-6";;
+	6)  tst_net_require_ipv6
+	    TST_IPV6=6 TST_IPVER=6 TST_IPV6_FLAG="-6"
+	    ;;
 	*) [ "$TST_PARSE_ARGS_CALLER" ] && $TST_PARSE_ARGS_CALLER "$1" "$2";;
 	esac
 }
@@ -100,6 +102,32 @@ tst_brk_()
 	[ -z "$TST_USE_LEGACY_API" ] && tst_brk $@ || tst_brkm $@
 }
 
+
+tst_net_detect_ipv6()
+{
+	local type="${1:-lhost}"
+	local cmd='[ -f /proc/net/if_inet6 ]'
+	local ret
+
+	if [ "$type" = "lhost" ]; then
+		$cmd
+	else
+		tst_rhost_run -c "$cmd"
+	fi
+	ret=$?
+
+	if [ $ret -eq 0 ]; then
+		TST_NET_IPV6_ENABLED=1
+	else
+		tst_res TINFO "IPv6 disabled on $type"
+	fi
+}
+
+tst_net_require_ipv6()
+{
+	[ "$TST_NET_IPV6_ENABLED" = 1 ] || tst_brk_ TCONF "IPv6 disabled"
+}
+
 init_ltp_netspace()
 {
 	local pid
@@ -517,7 +545,9 @@ tst_init_iface()
 		ip link set $iface down || return $?
 		ip route flush dev $iface || return $?
 		ip addr flush dev $iface || return $?
-		sysctl -qw net.ipv6.conf.$iface.accept_dad=0 || return $?
+		if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
+			sysctl -qw net.ipv6.conf.$iface.accept_dad=0 || return $?
+		fi
 		ip link set $iface up
 		return $?
 	fi
@@ -529,7 +559,9 @@ tst_init_iface()
 	tst_rhost_run -c "ip link set $iface down" || return $?
 	tst_rhost_run -c "ip route flush dev $iface" || return $?
 	tst_rhost_run -c "ip addr flush dev $iface" || return $?
-	tst_rhost_run -c "sysctl -qw net.ipv6.conf.$iface.accept_dad=0" || return $?
+	if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
+		tst_rhost_run -c "sysctl -qw net.ipv6.conf.$iface.accept_dad=0" || return $?
+	fi
 	tst_rhost_run -c "ip link set $iface up"
 }
 
@@ -606,7 +638,9 @@ tst_restore_ipaddr()
 	local ret=0
 	local backup_tst_ipv6=$TST_IPV6
 	TST_IPV6= tst_add_ipaddr $type $link_num || ret=$?
-	TST_IPV6=6 tst_add_ipaddr $type $link_num || ret=$?
+	if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
+		TST_IPV6=6 tst_add_ipaddr $type $link_num || ret=$?
+	fi
 	TST_IPV6=$backup_tst_ipv6
 
 	return $ret
@@ -937,6 +971,9 @@ tst_default_max_pkt()
 	echo "$((mtu + mtu / 10))"
 }
 
+# detect IPv6 support on lhost for tests which don't use test links
+tst_net_detect_ipv6
+
 [ -n "$TST_PRINT_HELP" -o -n "$TST_NET_SKIP_VARIABLE_INIT" ] && return 0
 
 # Management Link
@@ -971,8 +1008,13 @@ IPV6_RHOST="${IPV6_RHOST:-fd00:1:1:1::1/64}"
 if [ -z "$_tst_net_parse_variables" ]; then
 	eval $(tst_net_ip_prefix $IPV4_LHOST || echo "exit $?")
 	eval $(tst_net_ip_prefix -r $IPV4_RHOST || echo "exit $?")
-	eval $(tst_net_ip_prefix $IPV6_LHOST || echo "exit $?")
-	eval $(tst_net_ip_prefix -r $IPV6_RHOST || echo "exit $?")
+
+	tst_net_detect_ipv6 rhost
+
+	if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
+		eval $(tst_net_ip_prefix $IPV6_LHOST || echo "exit $?")
+		eval $(tst_net_ip_prefix -r $IPV6_RHOST || echo "exit $?")
+	fi
 fi
 
 [ -n "$TST_USE_NETNS" -a "$TST_INIT_NETNS" != "no" ] && init_ltp_netspace
@@ -981,19 +1023,26 @@ if [ -z "$_tst_net_parse_variables" ]; then
 	eval $(tst_net_iface_prefix $IPV4_LHOST || echo "exit $?")
 	eval $(tst_rhost_run -c 'tst_net_iface_prefix -r '$IPV4_RHOST \
 		|| echo "exit $?")
-	eval $(tst_net_iface_prefix $IPV6_LHOST || echo "exit $?")
-	eval $(tst_rhost_run -c 'tst_net_iface_prefix -r '$IPV6_RHOST \
-		|| echo "exit $?")
+
+	if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
+		eval $(tst_net_iface_prefix $IPV6_LHOST || echo "exit $?")
+		eval $(tst_rhost_run -c 'tst_net_iface_prefix -r '$IPV6_RHOST \
+			|| echo "exit $?")
+	fi
 
 	eval $(tst_net_vars $IPV4_LHOST/$IPV4_LPREFIX \
 		$IPV4_RHOST/$IPV4_RPREFIX || echo "exit $?")
-	eval $(tst_net_vars $IPV6_LHOST/$IPV6_LPREFIX \
-		$IPV6_RHOST/$IPV6_RPREFIX || echo "exit $?")
+
+	if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
+		eval $(tst_net_vars $IPV6_LHOST/$IPV6_LPREFIX \
+			$IPV6_RHOST/$IPV6_RPREFIX || echo "exit $?")
+	fi
 
 	tst_res_ TINFO "Network config (local -- remote):"
 	tst_res_ TINFO "$LHOST_IFACES -- $RHOST_IFACES"
 	tst_res_ TINFO "$IPV4_LHOST/$IPV4_LPREFIX -- $IPV4_RHOST/$IPV4_RPREFIX"
 	tst_res_ TINFO "$IPV6_LHOST/$IPV6_LPREFIX -- $IPV6_RHOST/$IPV6_RPREFIX"
+
 	export _tst_net_parse_variables="yes"
 fi
 
-- 
2.35.1