Clean up the switch-tagged header code.

Use MAC_ADDR_LEN in expressions representing offsets and lengths.

Don't declare the Ethernet header structure ourselves in the Broadcom
code, just print it the same way it's printed in the Marvell code.  Make
the two routines similar in other places as well.

Use "Unknown" rather than "unregistered" when printing the Ethernet type
field in the EDSA header - the value may well be registered even if it's
not in ethertype_values, it's just not a value we happen to have in that
table.

1 files changed, 22 insertions, 10 deletions

diff --git a/print-dsa.c b/print-dsa.c
index 3d142b28..ad247959 100644
--- a/print-dsa.c
+++ b/print-dsa.c
@@ -112,34 +112,35 @@ dsa_if_print_full(netdissect_options *ndo, const struct pcap_pkthdr *h,
 		  const u_char *p, u_int taglen)
 {
 	const u_char *edsa, *dsa;
-	int eflag, ret;
+	int save_eflag;
+	int ret;
 
-	if (h->caplen < 12 + taglen) {
+	if (h->caplen < 2*MAC_ADDR_LEN + taglen) {
 		nd_print_trunc(ndo);
 		return (h->caplen);
 	}
 
-	if (h->len < 12 + taglen) {
+	if (h->len < 2*MAC_ADDR_LEN + taglen) {
 		nd_print_trunc(ndo);
 		return (h->len);
 	}
 
 	if (taglen == EDSA_LEN) {
-		edsa = p + 12;
+		edsa = p + 2*MAC_ADDR_LEN;
 		dsa = edsa + 4;
 	} else {
 		edsa = NULL;
-		dsa = p + 12;
+		dsa = p + 2*MAC_ADDR_LEN;
 	}
 
 	if (ndo->ndo_eflag) {
 		ND_PRINT("%s > %s, ",
-			 etheraddr_string(ndo, p + 6),
+			 etheraddr_string(ndo, p + MAC_ADDR_LEN),
 			 etheraddr_string(ndo, p));
 
 		if (edsa) {
 			ND_PRINT("Marvell EDSA ethertype 0x%04x (%s), ", EDSA_ETYPE(edsa),
-				 tok2str(ethertype_values, "unregistered", EDSA_ETYPE(edsa)));
+				 tok2str(ethertype_values, "Unknown", EDSA_ETYPE(edsa)));
 			ND_PRINT("rsvd %u %u, ", edsa[2], edsa[3]);
 		} else {
 			ND_PRINT("Marvell DSA ");
@@ -209,11 +210,22 @@ dsa_if_print_full(netdissect_options *ndo, const struct pcap_pkthdr *h,
 		ND_PRINT("VLAN %u%c, ", DSA_VID(dsa), DSA_TAGGED(dsa) ? 't' : 'u');
 	}
 
-	eflag = ndo->ndo_eflag;
+	/* We printed the Ethernet destination and source addresses already */
+	save_eflag = ndo->ndo_eflag;
 	ndo->ndo_eflag = 0;
+
+	/* Parse the rest of the Ethernet header, and the frame payload,
+	 * telling ether_hdr_len_print() how big the non-standard Ethernet
+	 * header is.
+	 *
+	 * +-----------+-----------+---------------------+--------------+
+	 * | MAC DA (6)| MAC SA (6)|DSA/EDSA tag (taglen)|Type/Length(2)|
+	 * +-----------+-----------+---------------------+--------------+
+	 */
 	ret = ether_hdr_len_print(ndo, p, h->len, h->caplen, NULL, NULL,
-				  12 + taglen + 2);
-	ndo->ndo_eflag = eflag;
+				  2*MAC_ADDR_LEN + taglen + 2);
+
+	ndo->ndo_eflag = save_eflag;
 
 	return ret;
 }