A regression is introduced by the following commit:
	commit 
4d52cfbef6266092d535237ba5a4b981458ab171
	Author: Eric Dumazet <eric.dumazet@gmail.com>
	Date:   Tue Jun 2 00:42:16 2009 -0700
	    net: ipv4/ip_sockglue.c cleanups
	    Pure cleanups
but it is not a pure cleanup...
	-               if (val != -1 && (val < 1 || val>255))
	+               if (val != -1 && (val < 0 || val > 255))
Since there is no reason provided to allow ttl=0, change it back.
Reported-by: nitin padalia <padalia.nitin@gmail.com>
Cc: nitin padalia <padalia.nitin@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
        case IP_TTL:
                if (optlen < 1)
                        goto e_inval;
-               if (val != -1 && (val < 0 || val > 255))
+               if (val != -1 && (val < 1 || val > 255))
                        goto e_inval;
                inet->uc_ttl = val;
                break;