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, 2 insertions, 11 deletions

diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c
index 11490c4..57e8db8 100644
--- a/sys/netinet/ip_mroute.c
+++ b/sys/netinet/ip_mroute.c
@@ -22,7 +22,6 @@
 
 #include "opt_mac.h"
 #include "opt_mrouting.h"
-#include "opt_random_ip_id.h"
 
 #ifdef PIM
 #define _PIM_VT 1
@@ -1884,11 +1883,7 @@ encap_send(struct ip *ip, struct vif *vifp, struct mbuf *m)
      */
     ip_copy = mtod(mb_copy, struct ip *);
     *ip_copy = multicast_encap_iphdr;
-#ifdef RANDOM_IP_ID
-    ip_copy->ip_id = ip_randomid();
-#else
-    ip_copy->ip_id = htons(ip_id++);
-#endif
+    ip_copy->ip_id = ip_newid();
     ip_copy->ip_len += len;
     ip_copy->ip_src = vifp->v_lcl_addr;
     ip_copy->ip_dst = vifp->v_rmt_addr;
@@ -3093,11 +3088,7 @@ pim_register_send_rp(struct ip *ip, struct vif *vifp,
      */
     ip_outer = mtod(mb_first, struct ip *);
     *ip_outer = pim_encap_iphdr;
-#ifdef RANDOM_IP_ID
-    ip_outer->ip_id = ip_randomid();
-#else
-    ip_outer->ip_id = htons(ip_id++);
-#endif
+    ip_outer->ip_id = ip_newid();
     ip_outer->ip_len = len + sizeof(pim_encap_iphdr) + sizeof(pim_encap_pimhdr);
     ip_outer->ip_src = viftable[vifi].v_lcl_addr;
     ip_outer->ip_dst = rt->mfc_rp;