Add ARP statistics to the kernel and netstat.

New counters now exist for:
requests sent
replies sent
requests received
replies received
packets received
total packets dropped due to no ARP entry
entrys timed out
Duplicate IPs seen

The new statistics are seen in the netstat command
when it is given the -s command line switch.

MFC after:	2 weeks
In collaboration with: bz

1 files changed, 25 insertions, 6 deletions

diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index e118cec..c170c7a 100644
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -80,6 +80,7 @@ __FBSDID("$FreeBSD$");
 
 SYSCTL_DECL(_net_link_ether);
 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
+SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
 
 VNET_DEFINE(int, useloopback) = 1;	/* use loopback interface for
 					 * local traffic */
@@ -89,10 +90,12 @@ static VNET_DEFINE(int, arpt_keep) = (20*60);	/* once resolved, good for 20
 						 * minutes */
 static VNET_DEFINE(int, arp_maxtries) = 5;
 static VNET_DEFINE(int, arp_proxyall);
+static VNET_DEFINE(struct arpstat, arpstat);  /* ARP statistics, see if_arp.h */
 
 #define	V_arpt_keep		VNET(arpt_keep)
 #define	V_arp_maxtries		VNET(arp_maxtries)
 #define	V_arp_proxyall		VNET(arp_proxyall)
+#define	V_arpstat		VNET(arpstat)
 
 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
 	&VNET_NAME(arpt_keep), 0,
@@ -107,6 +110,9 @@ SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
 	&VNET_NAME(arp_proxyall), 0,
 	"Enable proxy ARP for all suitable requests");
+SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
+	&VNET_NAME(arpstat), arpstat,
+	"ARP statistics (struct arpstat, net/if_arp.h)");
 
 static void	arp_init(void);
 void		arprequest(struct ifnet *,
@@ -163,20 +169,23 @@ arptimer(void *arg)
 		return;
 	}
 	ifp = lle->lle_tbl->llt_ifp;
+	CURVNET_SET(ifp->if_vnet);
 	IF_AFDATA_LOCK(ifp);
 	LLE_WLOCK(lle);
-	if (((lle->la_flags & LLE_DELETED)
-		|| (time_second >= lle->la_expire))
-	    && (!callout_pending(&lle->la_timer) &&
-		callout_active(&lle->la_timer)))
+	if (((lle->la_flags & LLE_DELETED) ||
+	    (time_second >= lle->la_expire)) &&
+	    (!callout_pending(&lle->la_timer) &&
+	    callout_active(&lle->la_timer))) {
 		(void) llentry_free(lle);
-	else {
+		ARPSTAT_INC(timeouts);
+	} else {
 		/*
 		 * Still valid, just drop our reference
 		 */
 		LLE_FREE_LOCKED(lle);
 	}
 	IF_AFDATA_UNLOCK(ifp);
+	CURVNET_RESTORE();
 }
 
 /*
@@ -238,6 +247,7 @@ arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr  *tip,
 	sa.sa_len = 2;
 	m->m_flags |= M_BCAST;
 	(*ifp->if_output)(ifp, m, &sa, NULL);
+	ARPSTAT_INC(txrequests);
 }
 
 /*
@@ -339,8 +349,10 @@ retry:
 	 * latest one.
 	 */
 	if (m != NULL) {
-		if (la->la_hold != NULL)
+		if (la->la_hold != NULL) {
 			m_freem(la->la_hold);
+			ARPSTAT_INC(dropped);
+		}
 		la->la_hold = m;
 		if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
 			flags &= ~LLE_EXCLUSIVE;
@@ -413,6 +425,7 @@ arpintr(struct mbuf *m)
 		ar = mtod(m, struct arphdr *);
 	}
 
+	ARPSTAT_INC(received);
 	switch (ntohs(ar->ar_pro)) {
 #ifdef INET
 	case ETHERTYPE_IP:
@@ -493,6 +506,9 @@ in_arpinput(struct mbuf *m)
 	(void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
 	(void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
 
+	if (op == ARPOP_REPLY)
+		ARPSTAT_INC(rxreplies);
+
 	/*
 	 * For a bridge, we want to check the address irrespective
 	 * of the receive interface. (This will change slightly
@@ -603,6 +619,7 @@ match:
 		   ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
 		   inet_ntoa(isaddr), ifp->if_xname);
 		itaddr = myaddr;
+		ARPSTAT_INC(dupips);
 		goto reply;
 	}
 	if (ifp->if_flags & IFF_STATICARP)
@@ -686,6 +703,7 @@ match:
 reply:
 	if (op != ARPOP_REQUEST)
 		goto drop;
+	ARPSTAT_INC(rxrequests);
 
 	if (itaddr.s_addr == myaddr.s_addr) {
 		/* Shortcut.. the receiving interface is the target. */
@@ -774,6 +792,7 @@ reply:
 	sa.sa_family = AF_ARP;
 	sa.sa_len = 2;
 	(*ifp->if_output)(ifp, m, &sa, NULL);
+	ARPSTAT_INC(txreplies);
 	return;
 
 drop: