zero-pad MAC address to match ifconfig(8) output
https://sources.debian.org/patches/arpwatch/2.1a15-6/33_bug315215_zero-pad-MAC/

remove DECnet remnants

use a red-black tree instead of linked list for searching vendor IDs

Index: ec.c
--- ec.c.orig
+++ ec.c
@@ -58,20 +58,28 @@ struct rtentry;
 #include "arpwatch.h"
 #include "ec.h"
 #include "util.h"
+#include "tree.h"
 
 /* Basic data structure */
-struct ecent {
+struct ecnode {
+	RB_ENTRY(ecnode) entry;
 	u_int32_t o;		/* first 3 octets */
 	char *text;		/* associated text */
 };
 
-static struct ecent *list;
-static u_int ec_last = 0;
-static u_int ec_len = 0;
-
 /* Forwards */
-static int ec_a2o(char *, u_int32_t *);
+int ocmp(struct ecnode *, struct ecnode *);
 
+/* Compare two ecnode addresses */
+int
+ocmp(struct ecnode *e1, struct ecnode *e2)
+{
+	return (e1->o < e2->o ? -1 : e1->o > e2->o);
+}
+
+RB_HEAD(ectree, ecnode) head = RB_INITIALIZER(&head);
+RB_GENERATE(ectree, ecnode, entry, ocmp);
+
 /* Convert an 3 octets from an ethernet address to a u_int32_t */
 static int
 ec_a2o(register char *cp, register u_int32_t *op)
@@ -91,23 +99,18 @@ ec_a2o(register char *cp, register u_int32_t *op)
 int
 ec_add(register u_int32_t o, register char *text)
 {
+	struct ecnode *n;
 
-	if (ec_last >= ec_len) {
-		if (list == NULL) {
-			ec_len = 512;
-			list = malloc(ec_len * sizeof(*list));
-		} else {
-			ec_len *= 2;
-			list = realloc(list, ec_len * sizeof(*list));
-		}
-		if (list == NULL) {
-			syslog(LOG_ERR, "ec_add(): malloc: %m");
-			exit(1);
-		}
+	if ((n = malloc(sizeof(struct ecnode))) == NULL) {
+		syslog(LOG_ERR, "%s: malloc\n", __func__);
+		return (0);
 	}
-	list[ec_last].o = o;
-	list[ec_last].text = savestr(text);
-	++ec_last;
+
+	n->o = o;
+	n->text = savestr(text);
+
+	RB_INSERT(ectree, &head, n);
+
 	return (1);
 }
 
@@ -115,16 +118,16 @@ ec_add(register u_int32_t o, register char *text)
 char *
 ec_find(register u_char *e)
 {
-	u_int32_t o;
-	register int i;
+	struct ecnode find, *res;
+	u_int32_t o = 0;
 
-	o = 0;
 	BCOPY(e, &o, 3);
-	for (i = 0; i < ec_last; ++i)
-		if (list[i].o == o)
-			return (list[i].text);
-
-	return (NULL);
+	find.o = o;
+	res = RB_FIND(ectree, &head, &find);
+	if (res == NULL)
+		return (NULL);
+	else
+		return res->text;
 }
 
 /* Loop through the ethernet code database */
@@ -182,17 +185,6 @@ ec_loop(register FILE *f, ec_process fn, register cons
 	return (1);
 }
 
-/* DECnet local logical address prefix */
-static u_char decnet[3] = { 0xaa, 0x0, 0x4 };
-
-/* Returns true if an ethernet address is decnet, else false */
-int
-isdecnet(register u_char *e)
-{
-
-	return (MEMCMP(e, decnet, sizeof(decnet)) == 0);
-}
-
 /* Convert an ascii ethernet string to ethernet address */
 int
 str2e(register char *str, register u_char *e)
@@ -218,7 +210,7 @@ e2str(register u_char *e)
 {
 	static char str[32];
 
-	(void)sprintf(str, "%x:%x:%x:%x:%x:%x",
+	(void)sprintf(str, "%02x:%02x:%02x:%02x:%02x:%02x",
 	    e[0], e[1], e[2], e[3], e[4], e[5]);
 	return (str);
 }