just use sysctl_rdstruct in ip_input.c

[Claudio Jeker]

sysctl_rdstruct() does all the checking for read only sysctls.
Simplify the code a bit.

-- 
:wq Claudio

Index: netinet/ip_input.c
===================================================================
RCS file: /cvs/src/sys/netinet/ip_input.c,v
retrieving revision 1.244
diff -u -p -r1.244 ip_input.c
--- netinet/ip_input.c  12 Jan 2015 13:51:45 -0000      1.244
+++ netinet/ip_input.c  12 Jan 2015 21:53:37 -0000
@@ -1620,15 +1620,11 @@ ip_sysctl(int *name, u_int namelen, void
                return (sysctl_ifq(name + 1, namelen - 1,
                    oldp, oldlenp, newp, newlen, &ipintrq));
        case IPCTL_STATS:
-               if (newp != NULL)
-                       return (EPERM);
-               return (sysctl_struct(oldp, oldlenp, newp, newlen,
+               return (sysctl_rdstruct(oldp, oldlenp, newp,
                    &ipstat, sizeof(ipstat)));
        case IPCTL_MRTSTATS:
 #ifdef MROUTING
-               if (newp != NULL)
-                       return (EPERM);
-               return (sysctl_struct(oldp, oldlenp, newp, newlen,
+               return (sysctl_rdstruct(oldp, oldlenp, newp,
                    &mrtstat, sizeof(mrtstat)));
 #else
                return (EOPNOTSUPP);