Apply a simplifying patch submitted by rik to the IPX support in

netstat(1):

- Make previously unnecessarily global variables local.
- Use LIST_FOREACH() in preference to manual iteration.
- Restore a sanity check through slightly incestuous use of queue macro
  knowledge.

Submitted by:	rik

usr.bin/netstat/ipx.c

@@ -69,15 +69,8 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include "netstat.h"
 
-struct	ipxpcbhead ipxpcb_list;
-int	ipxpcb_list_read;
-struct	ipxpcb ipxpcb;
-struct	spxpcb spxpcb;
-struct	socket sockb;
-
 static char *ipx_prpr (struct ipx_addr *);
 
-static	int first = 1;
 extern char *tcpstates[];
 
 /*
@@ -90,44 +83,32 @@ extern char *tcpstates[];
 void
 ipxprotopr(u_long off, const char *name, int af1 __unused)
 {
-	struct ipxpcb cb;
-	struct ipxpcb *prev, *next;
+	struct ipxpcbhead cb;
+	struct ipxpcb *prev, *ipxp, *next;
+	struct ipxpcb ipxpcb;
+	struct spxpcb spxpcb;
+	struct socket sockb;
+	static int first = 1;
 	int isspx;
 
 	if (off == 0)
 		return;
 
-	/*
-	 * First time around, read in the pcb list header.  After that, we
-	 * walk sequential pcbs.
-	 */
-	if (ipxpcb_list_read == 0) {
-		kread(off, (char *)&ipxpcb_list, sizeof(ipxpcb_list));
-		off = (u_long)LIST_FIRST(&ipxpcb_list);
-		ipxpcb_list_read = 1;
-	}
-
 	isspx = strcmp(name, "spx") == 0;
-	kread(off, (char *)&cb, sizeof (struct ipxpcb));
-	ipxpcb = cb;
-	prev = (struct ipxpcb *)off;
-	if (LIST_NEXT(&ipxpcb, ipxp_list) == NULL)
-		return;
-	for (;LIST_NEXT(&ipxpcb, ipxp_list) != NULL; prev = next) {
+	kread(off, (char *)&cb, sizeof (struct ipxpcbhead));
+	next = LIST_FIRST (&cb);
+	LIST_FOREACH(ipxp, &cb, ipxp_list) {
 		u_long ppcb;
 
-		next = LIST_NEXT(&ipxpcb, ipxp_list);
+		prev = next;
+		next = ipxp;
 		kread((u_long)next, (char *)&ipxpcb, sizeof (ipxpcb));
-#if 0
-		/*
-		 * queue(9) macros do not give us a prev pointer, so skip
-		 * sanity check for now.
-		 */
-		if (ipxpcb.ipxp_prev != prev) {
+
+		if (*ipxpcb.ipxp_list.le_prev != prev) {
 			printf("???\n");
 			break;
 		}
-#endif
+
 		if (!aflag && ipx_nullhost(ipxpcb.ipxp_faddr) ) {
 			continue;
 		}
@@ -167,7 +148,6 @@ ipxprotopr(u_long off, const char *name, int af1 __unused)
 				printf(" %s", tcpstates[spxpcb.s_state]);
 		}
 		putchar('\n');
-		prev = next;
 	}
 }