selftests: forwarding: lib: Allow list of IPs for IGMPv3/MLDv2

The testsuite that checks for mcast_max_groups functionality will need
to generate IGMP and MLD packets with configurable number of (S,G)
addresses. To that end, further extend igmpv3_is_in_get() and
mldv2_is_in_get() to allow a list of IP addresses instead of one
address.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/forwarding/lib.sh

@@ -1768,11 +1768,12 @@ payload_template_nbytes()
 igmpv3_is_in_get()
 {
 	local GRP=$1; shift
-	local IP=$1; shift
+	local sources=("$@")
 
 	local igmpv3
+	local nsources=$(u16_to_bytes ${#sources[@]})
 
-	# IS_IN ( $IP )
+	# IS_IN ( $sources )
 	igmpv3=$(:
 		)"22:"$(			: Type - Membership Report
 		)"00:"$(			: Reserved
@@ -1781,9 +1782,12 @@ igmpv3_is_in_get()
 		)"00:01:"$(			: Number of Group Records
 		)"01:"$(			: Record Type - IS_IN
 		)"00:"$(			: Aux Data Len
-		)"00:01:"$(			: Number of Sources
+		)"${nsources}:"$(		: Number of Sources
 		)"$(ipv4_to_bytes $GRP):"$(	: Multicast Address
-		)"$(ipv4_to_bytes $IP)"$(	: Source Address
+		)"$(for src in "${sources[@]}"; do
+			ipv4_to_bytes $src
+			echo -n :
+		    done)"$(			: Source Addresses
 		)
 	local checksum=$(payload_template_calc_checksum "$igmpv3")
 
@@ -1794,10 +1798,11 @@ mldv2_is_in_get()
 {
 	local SIP=$1; shift
 	local GRP=$1; shift
-	local IP=$1; shift
+	local sources=("$@")
 
 	local hbh
 	local icmpv6
+	local nsources=$(u16_to_bytes ${#sources[@]})
 
 	hbh=$(:
 		)"3a:"$(			: Next Header - ICMPv6
@@ -1813,9 +1818,12 @@ mldv2_is_in_get()
 		)"00:01:"$(			: Number of Group Records
 		)"01:"$(			: Record Type - IS_IN
 		)"00:"$(			: Aux Data Len
-		)"00:01:"$(			: Number of Sources
+		)"${nsources}:"$(		: Number of Sources
 		)"$(ipv6_to_bytes $GRP):"$(	: Multicast address
-		)"$(ipv6_to_bytes $IP):"$(	: Source Address
+		)"$(for src in "${sources[@]}"; do
+			ipv6_to_bytes $src
+			echo -n :
+		    done)"$(			: Source Addresses
 		)
 
 	local len=$(u16_to_bytes $(payload_template_nbytes $icmpv6))