snoopy: add dns
 [rsc] --rw-rw-r-- M 779778 rsc sys 14815 Apr 13 15:32 sys/src/cmd/ip/snoopy/dns.c
 [rsc] --rw-rw-r-- M 779778 glenda sys 889 Apr 13 15:14 sys/src/cmd/ip/snoopy/mkfile
	/n/sourcesdump/2006/0413/plan9/sys/src/cmd/ip/snoopy/mkfile:5,10 - 
	/n/sourcesdump/2006/0414/plan9/sys/src/cmd/ip/snoopy/mkfile:5,11
	  	arp\
	  	bootp\
	  	dhcp\
	+ 	dns\
	  	dump\
	  	eap\
	  	eap_identity\
	/n/sourcesdump/2006/0413/plan9/sys/src/cmd/ip/snoopy/mkfile:46,51 - 
	/n/sourcesdump/2006/0414/plan9/sys/src/cmd/ip/snoopy/mkfile:47,53
	  	protos.h\
	  	y.tab.h\
	  
	+ YFILES=filter.y
	  
	  BIN=/$objtype/bin
	  UPDATE=\
	/n/sourcesdump/2006/0413/plan9/sys/src/cmd/ip/snoopy/mkfile:79,82 - 
	/n/sourcesdump/2006/0414/plan9/sys/src/cmd/ip/snoopy/mkfile:81,83
	  		echo '};'
	  	} > protos.c
	  
	- y.tab.c: filter.y
 [rsc] --rw-rw-r-- M 779778 glenda sys 2015 Apr 13 15:14 sys/src/cmd/ip/snoopy/udp.c
	/n/sourcesdump/2006/0413/plan9/sys/src/cmd/ip/snoopy/udp.c:39,44 - 
	/n/sourcesdump/2006/0414/plan9/sys/src/cmd/ip/snoopy/udp.c:39,45
	  
	  static Mux p_mux[] =
	  {
	+ 	{"dns",	53, },
	  	{"bootp",	67, },
	  	{"ninep",	6346, },	/* tvs */
	  	{"rtp",		ANYPORT, },
 [rsc] --rw-rw-r-- M 779778 rsc sys 14815 Apr 13 15:32 sys/src/cmd/ip/snoopy/dns.c
 [rsc] --rw-rw-r-- M 779778 glenda sys 3618 Apr 13 15:33 sys/src/cmd/ip/snoopy/tcp.c
	/n/sourcesdump/2006/0413/plan9/sys/src/cmd/ip/snoopy/tcp.c:50,55 - 
	/n/sourcesdump/2006/0414/plan9/sys/src/cmd/ip/snoopy/tcp.c:50,56
	  
	  static Mux p_mux[] =
	  {
	+ 	{"dns",	53, },
	  	{"ninep",	17007, },	/* exportfs */
	  	{"ninep",	564, },		/* 9fs */
	  	{"ninep",	17005, },	/* ocpu */