samples: pktgen: allow to specify destination IP range (CIDR)

Currently, kernel pktgen has the feature to specify destination
address range for sending packet. (e.g. pgset "dst_min/dst_max")

But on samples, each pktgen script doesn't have any option to achieve this.

This commit adds the feature to specify the destination address range with CIDR.

    -d : ($DEST_IP)   destination IP. CIDR (e.g. 198.18.0.0/15) is also allowed

    # ./pktgen_sample01_simple.sh -6 -d fe80::20/126 -p 3000 -n 4
    # tcpdump ip6 and udp
    05:14:18.082285 IP6 fe80::99.71 > fe80::23.3000: UDP, length 16
    05:14:18.082564 IP6 fe80::99.43 > fe80::23.3000: UDP, length 16
    05:14:18.083366 IP6 fe80::99.107 > fe80::22.3000: UDP, length 16
    05:14:18.083585 IP6 fe80::99.97 > fe80::21.3000: UDP, length 16

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/samples/pktgen/pktgen_bench_xmit_mode_queue_xmit.sh b/samples/pktgen/pktgen_bench_xmit_mode_queue_xmit.sh
index 0f33255..e607cb3 100755
--- a/samples/pktgen/pktgen_bench_xmit_mode_queue_xmit.sh
+++ b/samples/pktgen/pktgen_bench_xmit_mode_queue_xmit.sh
@@ -24,6 +24,10 @@
     err 1 "Bursting not supported for this mode"
 fi
 [ -z "$COUNT" ] && COUNT="10000000" # Zero means indefinitely
+if [ -n "$DEST_IP" ]; then
+    validate_addr${IP6} $DEST_IP
+    read -r DST_MIN DST_MAX <<< $(parse_addr${IP6} $DEST_IP)
+fi
 if [ -n "$DST_PORT" ]; then
     read -r UDP_DST_MIN UDP_DST_MAX <<< $(parse_ports $DST_PORT)
     validate_ports $UDP_DST_MIN $UDP_DST_MAX
@@ -54,7 +58,8 @@
 
     # Destination
     pg_set $dev "dst_mac $DST_MAC"
-    pg_set $dev "dst$IP6 $DEST_IP"
+    pg_set $dev "dst${IP6}_min $DST_MIN"
+    pg_set $dev "dst${IP6}_max $DST_MAX"
 
     if [ -n "$DST_PORT" ]; then
 	# Single destination port or random port range