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, 1 insertions, 6 deletions

diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 8f7003c..4946153 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -37,7 +37,6 @@
 #include "opt_ipsec.h"
 #include "opt_mac.h"
 #include "opt_pfil_hooks.h"
-#include "opt_random_ip_id.h"
 #include "opt_mbuf_stress_test.h"
 
 #include <sys/param.h>
@@ -216,11 +215,7 @@ ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro,
 	if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
 		ip->ip_v = IPVERSION;
 		ip->ip_hl = hlen >> 2;
-#ifdef RANDOM_IP_ID
-		ip->ip_id = ip_randomid();
-#else
-		ip->ip_id = htons(ip_id++);
-#endif
+		ip->ip_id = ip_newid();
 		ipstat.ips_localout++;
 	} else {
 		hlen = ip->ip_hl << 2;