Many network stack subsystems use a single global data structure to hold

all pertinent statatistics for the subsystem.  These structures are
sometimes "borrowed" by kernel modules that require a place to store
statistics for similar events.

Add KPI accessor functions for statistics structures referenced by kernel
modules so that they no longer encode certain specifics of how the data
structures are named and stored.  This change is intended to make it
easier to move to per-CPU network stats following 8.0-RELEASE.

The following modules are affected by this change:

      if_bridge
      if_cxgb
      if_gif
      ip_mroute
      ipdivert
      pf

In practice, most of these statistics consumers should, in fact, maintain
their own statistics data structures rather than borrowing structures
from the base network stack.  However, that change is too agressive for
this point in the release cycle.

Reviewed by:	bz
Approved by:	re (kib)

1 files changed, 14 insertions, 0 deletions

diff --git a/sys/netinet/ip_var.h b/sys/netinet/ip_var.h
index 74aecb1..448ba3d 100644
--- a/sys/netinet/ip_var.h
+++ b/sys/netinet/ip_var.h
@@ -131,11 +131,25 @@ struct	ipstat {
 
 #include <net/vnet.h>
 
+/*
+ * In-kernel consumers can use these accessor macros directly to update
+ * stats.
+ */
 #define	IPSTAT_ADD(name, val)	V_ipstat.name += (val)
 #define	IPSTAT_SUB(name, val)	V_ipstat.name -= (val)
 #define	IPSTAT_INC(name)	IPSTAT_ADD(name, 1)
 #define	IPSTAT_DEC(name)	IPSTAT_SUB(name, 1)
 
+/*
+ * Kernel module consumers must use this accessor macro.
+ */
+void	kmod_ipstat_inc(int statnum);
+#define	KMOD_IPSTAT_INC(name)						\
+	kmod_ipstat_inc(offsetof(struct ipstat, name) / sizeof(u_long))
+void	kmod_ipstat_dec(int statnum);
+#define	KMOD_IPSTAT_DEC(name)						\
+	kmod_ipstat_dec(offsetof(struct ipstat, name) / sizeof(u_long))
+
 /* flags passed to ip_output as last parameter */
 #define	IP_FORWARDING		0x1		/* most of ip header exists */
 #define	IP_RAWOUTPUT		0x2		/* raw ip header exists */