pf tests: support packet size range in pft_ether.py

Teach pft_ether.py to send a range of packet sizes. Use this to move the
size sweep into Python, removing the repeated Python startup overhead
and greatly speeding up the pf.ether.short_pkt test.

This should fix test timeouts seen on ci.freebsd.org.

While here also extend the range of packet sizes tested, because it adds
very little runtime now.

Sponsored by:	Rubicon Communications, LLC ("Netgate")

tests/sys/netpfil/pf/ether.sh

@@ -668,13 +668,10 @@ short_pkt_body()
 	# Try sending ever shorter ping requests
 	# BPF won't let us send anything shorter than an Ethernet header, but
 	# that's good enough for this test
-	for i in `seq 46 14`
-	do
-		$(atf_get_srcdir)/pft_ether.py \
-		    --sendif ${epair}a \
-		    --to 192.0.2.2 \
-		    --len ${i}
-	done
+	$(atf_get_srcdir)/pft_ether.py \
+	    --sendif ${epair}a \
+	    --to 192.0.2.2 \
+	    --len 14-64
 }
 
 short_pkt_cleanup()

tests/sys/netpfil/pf/pft_ether.py

@@ -61,7 +61,12 @@ def main():
 
 	args = parser.parse_args()
 
-	ping(args.sendif[0], args.to[0], int(args.len[0]))
+	if '-' in args.len[0]:
+		s=args.len[0].split('-')
+		for i in range(int(s[0]), int(s[1]) + 1):
+			ping(args.sendif[0], args.to[0], i)
+	else:
+		ping(args.sendif[0], args.to[0], int(args.len[0]))
 
 if __name__ == '__main__':
 	main()