From: Guy Harris <gharris@sonic.net>
Date: Thu, 28 May 2020 19:50:39 +0000 (-0700)
Subject: macsec, ether: clean up printing of encrypted and changed packets.
X-Git-Tag: tcpdump-4.99-bp~357
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/4e67f5b8391f7dc8be736611c5e5e5d35a2f5f1e

macsec, ether: clean up printing of encrypted and changed packets.

If the packet is encrypted or changed, so that we just print the payload
as raw data, and we're not running with -e, print the MAC addresses (if
any) and an indication that it's an 802.11AE packet, followed by the
MACsec header.
---

diff --git a/netdissect.h b/netdissect.h
index 2f25d416..3123bc38 100644
--- a/netdissect.h
+++ b/netdissect.h
@@ -629,7 +629,8 @@ extern void lwapp_data_print(netdissect_options *, const u_char *, u_int);
 extern void lwres_print(netdissect_options *, const u_char *, u_int);
 extern void m3ua_print(netdissect_options *, const u_char *, const u_int);
 extern int macsec_print(netdissect_options *, const u_char **,
-			 u_int *, u_int *, u_int *);
+			 u_int *, u_int *, u_int *, const struct lladdr_info *,
+			 const struct lladdr_info *);
 extern u_int mfr_print(netdissect_options *, const u_char *, u_int);
 extern void mobile_print(netdissect_options *, const u_char *, u_int);
 extern int mobility_print(netdissect_options *, const u_char *, const u_char *);
diff --git a/print-ether.c b/print-ether.c
index 4bf45731..205cc8a7 100644
--- a/print-ether.c
+++ b/print-ether.c
@@ -219,14 +219,11 @@ recurse:
 			printed_length = 1;
 		}
 
-		int ret = macsec_print(ndo, &p, &length, &caplen, &hdrlen);
+		int ret = macsec_print(ndo, &p, &length, &caplen, &hdrlen,
+		    &src, &dst);
 
 		if (ret == 0) {
 			/* Payload is encrypted; print it as raw data. */
-			if (!ndo->ndo_eflag) {
-				ether_type_print(ndo, length_type);
-				ND_PRINT(", length %u: ", orig_length);
-			}
 			if (!ndo->ndo_suppress_default_print)
 				ND_DEFAULTPRINT(p, caplen);
 			return (hdrlen);
diff --git a/print-macsec.c b/print-macsec.c
index 892f2c33..d409ddbb 100644
--- a/print-macsec.c
+++ b/print-macsec.c
@@ -89,9 +89,29 @@ static const struct tok macsec_flag_values[] = {
 	{ 0, NULL }
 };
 
+static void macsec_print_header(netdissect_options *ndo,
+				const struct macsec_sectag *sectag,
+				u_int short_length)
+{
+	ND_PRINT("an %u, pn %u, flags %s",
+		 GET_U_1(sectag->tci_an) & MACSEC_AN_MASK,
+		 GET_BE_U_4(sectag->packet_number),
+		 bittok2str_nosep(macsec_flag_values, "none",
+				  GET_U_1(sectag->tci_an) & MACSEC_TCI_FLAGS));
+
+	if (short_length != 0)
+		ND_PRINT(", sl %u", short_length);
+
+	if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC)
+		ND_PRINT(", sci " SCI_FMT, GET_BE_U_8(sectag->secure_channel_id));
+		
+	ND_PRINT(", ");
+}
+
 /* returns < 0 iff the packet can be decoded completely */
 int macsec_print(netdissect_options *ndo, const u_char **bp,
-		 u_int *lengthp, u_int *caplenp, u_int *hdrlenp)
+		 u_int *lengthp, u_int *caplenp, u_int *hdrlenp,
+		 const struct lladdr_info *src, const struct lladdr_info *dst)
 {
 	const char *save_protocol;
 	const u_char *p = *bp;
@@ -140,21 +160,8 @@ int macsec_print(netdissect_options *ndo, const u_char **bp,
 	}
 
 	short_length = GET_U_1(sectag->short_length) & MACSEC_SL_MASK;
-	if (ndo->ndo_eflag) {
-		ND_PRINT("an %u, pn %u, flags %s",
-			 GET_U_1(sectag->tci_an) & MACSEC_AN_MASK,
-			 GET_BE_U_4(sectag->packet_number),
-			 bittok2str_nosep(macsec_flag_values, "none",
-					  GET_U_1(sectag->tci_an) & MACSEC_TCI_FLAGS));
-
-		if (short_length != 0)
-			ND_PRINT(", sl %u", short_length);
-
-		if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC)
-			ND_PRINT(", sci " SCI_FMT, GET_BE_U_8(sectag->secure_channel_id));
-		
-		ND_PRINT(", ");
-	}
+	if (ndo->ndo_eflag)
+		macsec_print_header(ndo, sectag, short_length);
 
 	/* Skip the MACsec header. */
 	*bp += sectag_len;
@@ -166,8 +173,30 @@ int macsec_print(netdissect_options *ndo, const u_char **bp,
 
 	if ((GET_U_1(sectag->tci_an) & MACSEC_TCI_CONFID)) {
 		/*
-		 * The payload is encrypted.  Tell our
-		 * caller it can't be dissected.
+		 * The payload is encrypted.  Print link-layer
+		 * information, if it hasn't already been printed.
+		 */
+		if (!ndo->ndo_eflag) {
+			/*
+			 * Nobody printed the link-layer addresses,
+			 * so print them, if we have any.
+			 */
+			if (src != NULL && dst != NULL) {
+				ND_PRINT("%s > %s ",
+					(src->addr_string)(ndo, src->addr),
+					(dst->addr_string)(ndo, dst->addr));
+			}
+
+			ND_PRINT("802.1AE MACsec, ");
+
+			/*
+			 * Print the MACsec header.
+			 */
+			macsec_print_header(ndo, sectag, short_length);
+		}
+
+		/*
+		 * Tell our caller it can't be dissected.
 		 */
 		ndo->ndo_protocol = save_protocol;
 		return 0;