Get rid of the RANDOM_IP_ID option and make it a sysctl. NetBSD

have already done this, so I have styled the patch on their work:

        1) introduce a ip_newid() static inline function that checks
        the sysctl and then decides if it should return a sequential
        or random IP ID.

        2) named the sysctl net.inet.ip.random_id

        3) IPv6 flow IDs and fragment IDs are now always random.
        Flow IDs and frag IDs are significantly less common in the
        IPv6 world (ie. rarely generated per-packet), so there should
        be smaller performance concerns.

The sysctl defaults to 0 (sequential IP IDs).

Reviewed by:	andre, silby, mlaier, ume
Based on:	NetBSD
MFC after:	2 months

1 files changed, 0 insertions, 5 deletions

diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index b955f40..f5c3559 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -66,7 +66,6 @@
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
 #include "opt_pfil_hooks.h"
-#include "opt_random_ip_id.h"
 
 #include <sys/param.h>
 #include <sys/malloc.h>
@@ -1036,11 +1035,7 @@ skip_ipsec2:;
 	} else {
 		struct mbuf **mnext, *m_frgpart;
 		struct ip6_frag *ip6f;
-#ifdef RANDOM_IP_ID
 		u_int32_t id = htonl(ip6_randomid());
-#else
-		u_int32_t id = htonl(ip6_id++);
-#endif
 		u_char nextproto;
 		struct ip6ctlparam ip6cp;
 		u_int32_t mtu32;