Add a very simple debug tool that would dump list of interfaces,

addresses on each interface, and, associated refcounter. I found
it handy to check for address refcounter leaks.

tools/tools/ifpifa/Makefile

@@ -0,0 +1,10 @@
+# $FreeBSD$
+
+PROG=	ifpifa
+NO_MAN=
+WARNS?=6
+BINDIR?=/usr/local/bin
+DPADD=${LIBKVM}
+LDADD=-lkvm
+
+.include <bsd.prog.mk>

tools/tools/ifpifa/ifpifa.c

@@ -0,0 +1,190 @@
+/*-
+ * Copyright (c) 2012 maksim yevmenkin <emax@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* gcc -Wall -ggdb ifpifa.c -lkvm -o ifpifa */
+
+#include <sys/types.h>
+#include <sys/callout.h>
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <sys/protosw.h>
+#include <sys/queue.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+
+#include <net/if.h>
+#include <net/if_var.h>
+#include <net/if_dl.h>
+#include <net/if_types.h>
+#include <net/ethernet.h>
+#include <netinet/in.h>
+#include <netinet/in_var.h>
+#include <arpa/inet.h>
+
+#include <err.h>
+#include <fcntl.h>
+#include <kvm.h>
+#include <limits.h>
+#include <nlist.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+__FBSDID("$FreeBSD$");
+
+static struct nlist	nl[] = {
+#define N_IFNET         0
+        { .n_name = "_ifnet", },
+	{ .n_name = NULL, },
+};
+
+static int
+kread(kvm_t *kd, u_long addr, char *buffer, int size)
+{
+	if (kd == NULL || buffer == NULL)
+		return (-1);
+ 
+	if (kvm_read(kd, addr, buffer, size) != size) {
+		warnx("kvm_read: %s", kvm_geterr(kd));
+		return (-1);
+	}
+ 
+	return (0);
+}
+
+int
+main(void)
+{
+	kvm_t *kd;
+	char errbuf[_POSIX2_LINE_MAX];
+	u_long ifnetaddr, ifnetaddr_next;
+	u_long ifaddraddr, ifaddraddr_next;
+        struct ifnet ifnet;
+        struct ifnethead ifnethead;
+        union {
+		struct ifaddr ifa;
+		struct in_ifaddr in;
+		struct in6_ifaddr in6;
+        } ifaddr;
+	union {
+		struct sockaddr	*sa;
+		struct sockaddr_dl *sal;
+		struct sockaddr_in *sa4;
+		struct sockaddr_in6 *sa6;
+	} sa;
+	char addr[INET6_ADDRSTRLEN];
+
+	kd = kvm_openfiles(NULL, NULL, NULL, O_RDONLY, errbuf);
+	if (kd == NULL) {
+		warnx("kvm_openfiles: %s", errbuf);
+		exit(0);
+	}
+
+	if (kvm_nlist(kd, nl) < 0) {
+                warnx("kvm_nlist: %s", kvm_geterr(kd));
+                goto out;
+        }
+
+	if (nl[N_IFNET].n_type == 0) {
+		warnx("kvm_nlist: no namelist");
+		goto out;
+	}
+
+	if (kread(kd, nl[N_IFNET].n_value,
+		  (char *) &ifnethead, sizeof(ifnethead)) != 0)
+		goto out;
+
+	for (ifnetaddr = (u_long) TAILQ_FIRST(&ifnethead);
+	     ifnetaddr != 0;
+	     ifnetaddr = ifnetaddr_next) {
+		if (kread(kd, ifnetaddr, (char *) &ifnet, sizeof(ifnet)) != 0)
+			goto out;
+		ifnetaddr_next = (u_long) TAILQ_NEXT(&ifnet, if_link);
+
+		printf("%s\n", ifnet.if_xname);
+
+		for (ifaddraddr = (u_long) TAILQ_FIRST(&ifnet.if_addrhead);
+		     ifaddraddr != 0;
+		     ifaddraddr = ifaddraddr_next) {
+			if (kread(kd, ifaddraddr,
+				  (char *) &ifaddr, sizeof(ifaddr)) != 0)
+				goto out;
+
+			ifaddraddr_next = (u_long)
+				TAILQ_NEXT(&ifaddr.ifa, ifa_link);
+
+			sa.sa = (struct sockaddr *)(
+				(unsigned char *) ifaddr.ifa.ifa_addr -
+				(unsigned char *) ifaddraddr +
+				(unsigned char *) &ifaddr);
+
+			switch (sa.sa->sa_family) {
+			case AF_LINK:
+				switch (sa.sal->sdl_type) {
+				case IFT_ETHER:
+				case IFT_FDDI:
+	     				ether_ntoa_r((struct ether_addr * )
+						LLADDR(sa.sal), addr);
+					break;
+
+				case IFT_LOOP:
+					strcpy(addr, "loopback");
+					break;
+
+				default:
+					snprintf(addr, sizeof(addr),
+						 "<Link type %#x>",
+						sa.sal->sdl_type);
+					break;
+				}
+				break;
+
+			case AF_INET:
+				inet_ntop(AF_INET, &sa.sa4->sin_addr,
+					addr, sizeof(addr)); 
+				break;
+
+			case AF_INET6:
+				inet_ntop(AF_INET6, &sa.sa6->sin6_addr,
+					addr, sizeof(addr)); 
+				break;
+
+			default:
+				snprintf(addr, sizeof(addr), "family=%d",
+					sa.sa->sa_family);
+				break;
+			}
+		
+			printf("\t%s ifa_refcnt=%u\n",
+				addr, ifaddr.ifa.ifa_refcnt);
+		}
+	}
+out:
+	kvm_close(kd);
+
+	return (0);
+}
+