MFC r196797:

Add ARP statistics to the kernel and netstat.

sys/net/if_arp.h

@@ -108,6 +108,31 @@ struct	arpcom {
 #define IFP2AC(ifp) ((struct arpcom *)(ifp->if_l2com))
 #define AC2IFP(ac) ((ac)->ac_ifp)
 
-#endif
+#endif /* _KERNEL */
+
+struct arpstat {
+	/* Normal things that happen: */
+	u_long txrequests;	/* # of ARP requests sent by this host. */
+	u_long txreplies;	/* # of ARP replies sent by this host. */
+	u_long rxrequests;	/* # of ARP requests received by this host. */
+	u_long rxreplies;	/* # of ARP replies received by this host. */
+	u_long received;	/* # of ARP packets received by this host. */
+
+	u_long arp_spares[4];	/* For either the upper or lower half. */
+	/* Abnormal event and error  counting: */
+	u_long dropped;		/* # of packets dropped waiting for a reply. */
+	u_long timeouts;	/* # of times with entries removed */
+				/* due to timeout. */
+	u_long dupips;		/* # of duplicate IPs detected. */
+};
+
+/*
+ * In-kernel consumers can use these accessor macros directly to update
+ * stats.
+ */
+#define	ARPSTAT_ADD(name, val)	V_arpstat.name += (val)
+#define	ARPSTAT_SUB(name, val)	V_arpstat.name -= (val)
+#define	ARPSTAT_INC(name)	ARPSTAT_ADD(name, 1)
+#define	ARPSTAT_DEC(name)	ARPSTAT_SUB(name, 1)
 
 #endif /* !_NET_IF_ARP_H_ */

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 */
@@ -91,11 +92,13 @@ static VNET_DEFINE(int, arpt_down) = 20;      /* keep incomplete entries for
 					       * 20 seconds */
 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_arpt_down		VNET(arpt_down)
 #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,
@@ -110,6 +113,9 @@ 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 *,
@@ -166,6 +172,7 @@ 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_STATIC)
@@ -174,6 +181,7 @@ arptimer(void *arg)
 		if (!callout_pending(&lle->la_timer) &&
 		    callout_active(&lle->la_timer)) {
 			(void) llentry_free(lle);
+			ARPSTAT_INC(timeouts);
 		} 
 #ifdef DIAGNOSTIC
 		else {
@@ -186,6 +194,7 @@ arptimer(void *arg)
 #endif
 	}
 	IF_AFDATA_UNLOCK(ifp);
+	CURVNET_RESTORE();
 }
 
 /*
@@ -247,6 +256,7 @@ 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);
 }
 
 /*
@@ -348,8 +358,10 @@ 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;
@@ -422,6 +434,7 @@ arpintr(struct mbuf *m)
 		ar = mtod(m, struct arphdr *);
 	}
 
+	ARPSTAT_INC(received);
 	switch (ntohs(ar->ar_pro)) {
 #ifdef INET
 	case ETHERTYPE_IP:
@@ -502,6 +515,9 @@ 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
@@ -612,6 +628,7 @@ 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)
@@ -695,6 +712,7 @@ 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. */
@@ -791,6 +809,7 @@ reply:
 	sa.sa_family = AF_ARP;
 	sa.sa_len = 2;
 	(*ifp->if_output)(ifp, m, &sa, NULL);
+	ARPSTAT_INC(txreplies);
 	return;
 
 drop:

usr.bin/netstat/inet.c

@@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 
 #include <net/route.h>
+#include <net/if_arp.h>
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
@@ -871,6 +872,47 @@ ip_stats(u_long off, const char *name, int af1 __unused, int proto __unused)
 #undef p1a
 }
 
+/*
+ * Dump ARP statistics structure.
+ */
+void
+arp_stats(u_long off, const char *name, int af1 __unused, int proto __unused)
+{
+	struct arpstat arpstat, zerostat;
+	size_t len = sizeof(arpstat);
+
+	if (live) {
+		if (zflag)
+			memset(&zerostat, 0, len);
+		if (sysctlbyname("net.link.ether.arp.stats", &arpstat, &len,
+		    zflag ? &zerostat : NULL, zflag ? len : 0) < 0) {
+			warn("sysctl: net.link.ether.arp.stats");
+			return;
+		}
+	} else
+		kread(off, &arpstat, len);
+
+	printf("%s:\n", name);
+
+#define	p(f, m) if (arpstat.f || sflag <= 1) \
+    printf(m, arpstat.f, plural(arpstat.f))
+#define	p2(f, m) if (arpstat.f || sflag <= 1) \
+    printf(m, arpstat.f, pluralies(arpstat.f))
+
+	p(txrequests, "\t%lu ARP request%s sent\n");
+	p2(txreplies, "\t%lu ARP repl%s sent\n");
+	p(rxrequests, "\t%lu ARP request%s received\n");
+	p2(rxreplies, "\t%lu ARP repl%s received\n");
+	p(received, "\t%lu ARP packet%s received\n");
+	p(dropped, "\t%lu total packet%s dropped due to no ARP entry\n");
+	p(timeouts, "\t%lu ARP entry%s timed out\n");
+	p(dupips, "\t%lu Duplicate IP%s seen\n");
+#undef p
+#undef p2
+}
+
+
+
 static	const char *icmpnames[ICMP_MAXTYPE + 1] = {
 	"echo reply",			/* RFC 792 */
 	"#1",

usr.bin/netstat/main.c

@@ -184,6 +184,8 @@ static struct nlist nl[] = {
 	{ .n_name = "_sctpstat" },
 #define	N_MFCTABLESIZE	54
 	{ .n_name = "_mfctablesize" },
+#define N_ARPSTAT       55
+	{ .n_name = "_arpstat" },
 	{ .n_name = NULL },
 };
 
@@ -232,6 +234,8 @@ struct protox {
 	  carp_stats,	NULL,		"carp",	1,	0 },
 	{ -1,		N_PFSYNCSTAT,	1,	NULL,
 	  pfsync_stats,	NULL,		"pfsync", 1,	0 },
+	{ -1,		N_ARPSTAT,	1,	NULL,
+	  arp_stats,	NULL,		"arp", 1,	0 },
 	{ -1,		-1,		0,	NULL,
 	  NULL,		NULL,		NULL,	0,	0 }
 };

usr.bin/netstat/netstat.h

@@ -75,6 +75,7 @@ void	udp_stats(u_long, const char *, int, int);
 void	sctp_protopr(u_long, const char *, int, int);
 void	sctp_stats(u_long, const char *, int, int);
 #endif
+void	arp_stats(u_long, const char *, int, int);
 void	ip_stats(u_long, const char *, int, int);
 void	icmp_stats(u_long, const char *, int, int);
 void	igmp_stats(u_long, const char *, int, int);