#!/bin/sh
# Helper functions for testing mdnsd

# Session set from Makefile before calling unshare -mrun
if [ -z "$SESSION" ]; then
	SESSION=$(mktemp -d mdnsd.XXXXXXXX)
	TMPSESS=1
fi

# Test name, used everywhere as /tmp/$NM/foo
NM=$(basename "$0" .sh)
SRC=${top_srcdir:-..}
DIR="${SESSION}/${NM}"
client="${DIR}/client"
server="${DIR}/server"
client_addr=192.168.42.101
server_addr=192.168.42.1
client_addr_ll6=
server_addr_ll6=
client_addr_6=2001:db8:0:f101::2a:65
server_addr_6=2001:db8:0:f101::2a:1

# Print heading for test phases
print()
{
	printf "\e[7m>> %-80s\e[0m\n" "$1"
}

SKIP()
{
	print "TEST: SKIP"
	[ $# -gt 0 ] && echo "$*"
	exit 77
}

FAIL()
{
	print "TEST: FAIL"
	[ $# -gt 0 ] && echo "$*"
	exit 99
}

OK()
{
	print "TEST: OK"
	[ $# -gt 0 ] && echo "$*"
	exit 0
}

# prefer source tree build, fall back to check one level up
mdnsd()
{
	ARGS=$@
	bin="../src/mdnsd"
	[ -x "$bin" ] || SKIP "Cannot find mdnsd"

	print "Starting mdnsd ..."
	nsenter --net="$server" -- "$bin" -H test -n "${SRC}/examples" $ARGS &
	echo "$! mdnsd" >>"${DIR}/pids"
	sleep 1
}

# stop all instances of the mdnsd
mdnsd_stop()
{
	[ -f "${DIR}/pids" ] || SKIP "Cannot find PID file"

	print "Stopping mdnsd ..."
	leftpids=""
	while read pid prog; do
		if [ x"$prog" = x"mdnsd" ] ; then
			kill "$pid" 2>/dev/null
		else
			leftpids="${leftpids}$pid $prog\n"
		fi
	done < "${DIR}/pids"
	echo -n "${leftpids}" > "${DIR}/pids"

	sleep 1
}

# prefer source tree build, fall back to check one level up
_mquery()
{
	ns=$1; shift
	bin="../src/mquery"
#	bin="/usr/bin/mdns-scan"
	[ -x "$bin" ] || SKIP "Cannot find mquery"
	nsenter --net="$ns" -- "$bin" -i eth0 -w 2 "$@"
}

# Query from the client, or (mquery_local) from the mdnsd host itself
mquery()       { _mquery "$client" "$@"; }
mquery_local() { _mquery "$server" "$@"; }

discover()
{
	print "Starting mquery to locate mdnsd ..."
	mquery >"$DIR/result" || FAIL "Not found"

	# shellcheck disable=SC2154
	grep -q "+ _ftp._tcp.local. ($server_addr)" "$DIR/result" || FAIL
}

browse()
{
	print "Browsing _ftp._tcp.local. for its service instance ..."
	mquery -t 12 _ftp._tcp.local. >"$DIR/result" || FAIL "Query failed"

	# RFC 6763 §4.1: the service PTR must resolve to the instance name,
	# so a browser can follow it to the SRV/TXT records.  See #80.
	# shellcheck disable=SC2154
	grep -q "+ Troglobit FTP Server._ftp._tcp.local. ($server_addr)" \
		"$DIR/result" || FAIL "Service PTR does not point to the instance name"

	print "Resolving the instance SRV to its target host ..."
	mquery -s -t 33 "Troglobit FTP Server._ftp._tcp.local." >"$DIR/srv" \
		|| FAIL "SRV query failed"

	# The SRV target is the daemon's host name (mdnsd -H test), shared by
	# all of its services, not a per-service name.
	grep -q "to test.local.:21" "$DIR/srv" \
		|| FAIL "SRV target is not the shared host name"
}

# Browse over the IPv6 transport (ff02::fb).  See issue #10.
browse6()
{
	# shellcheck disable=SC2154
	../src/mquery -h 2>&1 | grep -q '\[-6\]' || SKIP "built without IPv6 support"

	print "Browsing _ftp._tcp.local. over IPv6 ..."
	mquery -6 -t 12 _ftp._tcp.local. >"$DIR/result6" || FAIL "IPv6 query failed"
	cat "$DIR/result6"
	grep -q "+ Troglobit FTP Server._ftp._tcp.local." "$DIR/result6" \
		|| FAIL "service not discoverable over IPv6"

	print "Resolving the instance SRV over IPv6 ..."
	mquery -6 -s -t 33 "Troglobit FTP Server._ftp._tcp.local." >"$DIR/srv6" \
		|| FAIL "IPv6 SRV query failed"
	grep -q "to test.local.:21" "$DIR/srv6" \
		|| FAIL "SRV not resolvable over IPv6"
}

# Gather a pcap of the session
# Example:
#          collect eth0 -c10 'dst 224.0.0.251'
# Dump:
#          tshark -r "$DIR/pcap" 2>/dev/null | grep foo
#
collect()
{
    print "Starting collector on $client ..."
    nsenter --net="$client" -- tshark -w "$DIR/pcap" -lni eth0 2>/dev/null &
    echo "$! tshark" >> "$DIR/pids"
    sleep 2
}

# stop all instances of the pcap collector
stop_collect()
{
	[ -f "${DIR}/pids" ] || SKIP "Cannot find PID file"

	print "Stopping collector ..."
	leftpids=""
	while read pid prog; do
		if [ x"$prog" = x"tshark" ] ; then
			kill "$pid" 2>/dev/null
		else
			leftpids="${leftpids}$pid $prog\n"
		fi
	done < "${DIR}/pids"
	echo -n "${leftpids}" > "${DIR}/pids"

	sleep 1
}

# Set up two logically separated network namespaces, connected via a
# VETH pair, to simulate a basic LAN with two devices; one for mdnsd
# and one client (mquery)
topo_basic()
{
	local sllip
	local to

	if [ ! -e "$server" ]; then
		touch "$server"
		unshare --net="$server" -- ip link set lo up
	fi

	nsenter --net="$server" -- ip link add eth0 type veth peer tmp0
	nsenter --net="$server" -- ip link set tmp0 netns $$
	nsenter --net="$server" -- ip link set eth0 up
	nsenter --net="$server" -- ip link set eth0 multicast on
	nsenter --net="$server" -- ip addr add "${server_addr}"/24 dev eth0
	nsenter --net="$server" -- ip route add default via "${server_addr}"

	if [ ! -e "$client" ]; then
		touch "$client"
		unshare --net="$client" -- ip link set lo up
	fi

	nsenter --net="$client" -- sleep 2 &
	sleep 0.3
	ip link set tmp0 netns $!
	nsenter --net="$client" -- ip link set tmp0 name eth0
	nsenter --net="$client" -- ip link set eth0 up
	nsenter --net="$client" -- ip link set eth0 multicast on
	nsenter --net="$client" -- ip addr add "${client_addr}"/24 dev eth0
	nsenter --net="$client" -- ip route add default via "${client_addr}"

	nsenter --net="$server" -- ip -br link  > "$DIR/tmp"
	nsenter --net="$server" -- ip -br addr >> "$DIR/tmp"
	nsenter --net="$server" -- ip -br rout >> "$DIR/tmp"
	echo "Server"
	awk '{print "     "$0}' "$DIR/tmp"
	sllip=$(grep "eth0" "$DIR/tmp" | grep -i "fe80" | sed -e 's;.*\(fe80::.*\)/64.*;\1;')
	if [ -n "$sllip" ] ; then server_addr_ll6=$sllip ; fi
	nsenter --net="$client" -- ip -br link  > "$DIR/tmp"
	nsenter --net="$client" -- ip -br addr >> "$DIR/tmp"
	nsenter --net="$client" -- ip -br rout >> "$DIR/tmp"
	echo "Client"
	awk '{print "     "$0}' "$DIR/tmp"
	sllip=$(grep "eth0" "$DIR/tmp" | grep -i "fe80" | sed -e 's;.*\(fe80::.*\)/64.*;\1;')
	if [ -n "$sllip" ] ; then client_addr_ll6=$sllip ; fi

	# Wait for DAD to finish on BOTH ends so the link-local addresses are
	# valid -- pinging a still-tentative peer fails, which slower setups
	# such as `make distcheck` trip over.  dad_transmits + a few seconds.
	to=$(nsenter --net="$client" -- cat /proc/sys/net/ipv6/conf/eth0/dad_transmits)
	to=$((to + 3))
	while [ $to -gt 0 ] ; do
		tentative=$(nsenter --net="$client" -- ip -6 addr show dev eth0 tentative
			    nsenter --net="$server" -- ip -6 addr show dev eth0 tentative)
		[ -z "$tentative" ] && break
		sleep 1
		: $((to -= 1))
	done

	echo "$server" >> "$DIR/mounts"
	echo "$client" >> "$DIR/mounts"

	print "Verifying IPv4 connectivity ..."
	nsenter --net="$client" -- ping -c1 "${server_addr}" || FAIL "No IPv4 connectivity"

	print "Verifying IPv6 connectivity ..."
	nsenter --net="$client" -- ping6 -c 1 ${server_addr_ll6} || FAIL "No IPv6 connectivity"
}

topo_teardown()
{
	if [ -z "$NM" ]; then
		echo "NM variable unset, skippnig teardown"
		exit 1
	fi

	mdnsd_stop

	# shellcheck disable=SC2162
	if [ -f "${DIR}/pids" ]; then
		while read pid prog; do
			kill -9 "$pid" 2>/dev/null
		done < "${DIR}/pids"
	fi

	if [ -n "$KEEP_TEST_DATA" ]; then
		return
	fi

	# shellcheck disable=SC2162
	if [ -f "${DIR}/mounts" ]; then
		while read ln; do
			echo "Unmounting $ln and removing ..."
			umount "$ln"
			rm -f "$ln"
		done < "${DIR}/mounts"
	fi

# NOTE: Uncomment the following two lines for debugging tests
#	echo "Resulting files in ${DIR}"
#	return;
	rm -rf "${DIR}"
	if [ -n "$TMPSESS" ] && [ -d "$SESSION" ]; then
		rm -rf "$SESSION"
	fi
}

signal()
{
	echo
	if [ "$1" != "EXIT" ]; then
		print "Got signal, cleaning up"
	fi
	topo_teardown
}

# props to https://stackoverflow.com/a/2183063/1708249
# shellcheck disable=SC2064
trapit()
{
	func="$1" ; shift
	for sig ; do
		trap "$func $sig" "$sig"
	done
}

topo()
{
	if [ $# -lt 1 ]; then
		print "Too few arguments to topo()"
		exit 1
	fi
	t=$1
	shift

	print "Creating world ..."
	case "$t" in
		basic)
			topo_basic
			;;
		teardown)
			topo_teardown
			;;
		*)
			print "No such topology: $t"
			exit 1
			;;
	esac
}

# Runs once when including lib.sh
mkdir -p "${DIR}"
touch "${DIR}/pids"
touch "${DIR}/mounts"
trapit signal INT TERM QUIT EXIT