[LTP] [PATCH 8/9] tst_net.sh: Harden on disabled IPv6 via sysctl

[Petr Vorel]

Detect IPv6 can be disabled via sysctl (for both netns or on ssh based
links) and tests than fails:

    # sysctl net.ipv6.conf.ltp_ns_veth2.disable_ipv6=1
    # TST_NET_RHOST_RUN_DEBUG=1 ./ping02.sh -6
    ping02 1 TINFO: tst_rhost_run: cmd: [ -f /proc/net/if_inet6 ]
    ping02 1 TINFO: NETNS: sh -c " [ -f /proc/net/if_inet6 ] || echo RTERR" 2>&1
    ping02 1 TINFO: initialize 'lhost' 'ltp_ns_veth2' interface
    ping02 1 TINFO: add local addr 10.0.0.2/24
    ping02 1 TINFO: add local addr fd00:1:1:1::2/64
    RTNETLINK answers: Permission denied
    ping02 1 TINFO: initialize 'rhost' 'ltp_ns_veth1' interface
    ...
    ping02 1 TINFO: timeout per run is 0h 5m 0s
    ping6: connect: Network is unreachable
    ping02 1 TFAIL: ping6 -I ltp_ns_veth2 -c 3 -s 8 -f -p 000102030405060708090a0b0c0d0e0f fd00:1:1:1::1 >/dev/null failed unexpectedly

Therefore detect IPv6 disabled via sysctl:
1) tst_init_iface - to avoid setting net.ipv6.conf.$iface.accept_dad=0.
tst_init_iface is called by tst_restore_ipaddr, which is called by
init_ltp_netspace (netns) at the start of testing.
2) For ssh are all devices tested at the start.

There are guards in both functions to avoid repeated checks (e.g.
tst_restore_ipaddr() it's also cleanup function for some tests therefore
called by both netns and ssh).

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
 testcases/lib/tst_net.sh | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/testcases/lib/tst_net.sh b/testcases/lib/tst_net.sh
index 518a3ed579..7ee8594a54 100644
--- a/testcases/lib/tst_net.sh
+++ b/testcases/lib/tst_net.sh
@@ -126,6 +126,43 @@ tst_net_require_ipv6()
 	[ "$TST_NET_IPV6_ENABLED" = 1 ] || tst_brk_ TCONF "IPv6 disabled"
 }
 
+# Detect IPv6 disabled via sysctl.
+tst_net_detect_ipv6_sysctl()
+{
+	[ "$TST_NET_IPV6_ENABLED" = 1 ] || return 1
+
+	local iface="$1"
+	local type="${2:-lhost}"
+	local check="sysctl -n net.ipv6.conf.$iface.disable_ipv6"
+	local disabled
+
+	if [ "$type" = "lhost" ]; then
+		disabled=$($check)
+	else
+		disabled=$(tst_rhost_run -c "$check")
+	fi
+	if [ $disabled = 1 ]; then
+		tst_res_ TINFO "IPv6 disabled on $type on $iface"
+		TST_NET_IPV6_ENABLED=0
+		return 1
+	fi
+
+	return 0
+}
+
+tst_net_check_ifaces_ipv6()
+{
+	local iface
+
+	for iface in $(tst_get_ifaces); do
+		tst_net_detect_ipv6_sysctl || return
+	done
+
+	for iface in $(tst_get_ifaces rhost); do
+		tst_net_detect_ipv6_sysctl $iface rhost || return
+	done
+}
+
 init_ltp_netspace()
 {
 	local pid
@@ -531,7 +568,9 @@ tst_init_iface()
 	local type="${1:-lhost}"
 	local link_num="${2:-0}"
 	local iface="$(tst_iface $type $link_num)"
+
 	tst_res_ TINFO "initialize '$type' '$iface' interface"
+	tst_net_detect_ipv6_sysctl $iface $type
 
 	if [ "$type" = "lhost" ]; then
 		if ip xfrm state 1>/dev/null 2>&1; then
@@ -1015,6 +1054,7 @@ if [ "$TST_NET_IPV6_ENABLED" = 1 ]; then
 fi
 
 tst_net_use_netns && init_ltp_netspace
+tst_net_check_ifaces_ipv6
 
 eval $(tst_net_iface_prefix $IPV4_LHOST || echo "exit $?")
 eval $(tst_rhost_run -c 'tst_net_iface_prefix -r '$IPV4_RHOST \
-- 
2.39.1