HSR/PRP: Add printing for HSR header

HSR is a redundancy protocol that duplicates traffic and sends it two
ways in a ring with an HSR header that includes a sequence number. Other
devices in the ring will forward the first occurrence of a packet, and
discard the duplicate (based on SMAC + sequence number). This enables
zero packet loss when a link goes down.

Signed-off-by: Casper Andersson <casper.casan@gmail.com>

CMakeLists.txt

@@ -1124,6 +1124,7 @@ set(NETDISSECT_SOURCE_LIST_C
     print-geonet.c
     print-gre.c
     print-hncp.c
+    print-hsr-prp.c
     print-hsrp.c
     print-http.c
     print-icmp.c

Makefile.in

@@ -142,6 +142,7 @@ LIBNETDISSECT_SRC=\
 	print-geonet.c \
 	print-gre.c \
 	print-hncp.c \
+	print-hsr-prp.c \
 	print-hsrp.c \
 	print-http.c \
 	print-icmp.c \

ethertype.h

@@ -185,6 +185,9 @@
 #ifndef ETHERTYPE_PTP
 #define ETHERTYPE_PTP		0x88f7
 #endif
+#ifndef ETHERTYPE_HSR
+#define ETHERTYPE_HSR		0x892f
+#endif
 #ifndef	ETHERTYPE_LOOPBACK
 #define	ETHERTYPE_LOOPBACK	0x9000
 #endif

netdissect.h

@@ -654,6 +654,7 @@ extern void hex_and_ascii_print(netdissect_options *, const char *, const u_char
 extern void hex_print(netdissect_options *, const char *indent, const u_char *cp, u_int);
 extern void hex_print_with_offset(netdissect_options *, const char *indent, const u_char *cp, u_int, u_int);
 extern void hncp_print(netdissect_options *, const u_char *, u_int);
+extern void hsr_print(netdissect_options *, const u_char *, u_int);
 extern void hsrp_print(netdissect_options *, const u_char *, u_int);
 extern void http_print(netdissect_options *, const u_char *, u_int);
 extern void icmp6_print(netdissect_options *, const u_char *, u_int, const u_char *, int);

print-ether.c

@@ -103,6 +103,7 @@ const struct tok ethertype_values[] = {
     { ETHERTYPE_CALM_FAST,      "CALM FAST"},
     { ETHERTYPE_AOE,            "AoE" },
     { ETHERTYPE_PTP,            "PTP" },
+    { ETHERTYPE_HSR,            "HSR" },
     { ETHERTYPE_ARISTA,         "Arista Vendor Specific Protocol" },
     { 0, NULL}
 };
@@ -287,6 +288,24 @@ ether_common_print(netdissect_options *ndo, const u_char *p, u_int length,
 		hdrlen += 4;
 	}
 
+	if (length_type == ETHERTYPE_HSR) {
+		if (ndo->ndo_eflag) {
+			ether_type_print(ndo, length_type);
+			if (!printed_length) {
+				ND_PRINT(", length %u: ", orig_length);
+				printed_length = 1;
+			} else
+				ND_PRINT(", ");
+			hsr_print(ndo, p, length);
+		}
+
+		length_type = GET_BE_U_2(p + 4);
+		p += 6;
+		length -= 6;
+		caplen -= 6;
+		hdrlen += 6;
+	}
+
 	/*
 	 * We now have the final length/type field.
 	 */

print-hsr-prp.c

@@ -0,0 +1,72 @@
+/*
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code
+ * distributions retain the above copyright notice and this paragraph
+ * in its entirety, and (2) distributions including binary code include
+ * the above copyright notice and this paragraph in its entirety in
+ * the documentation or other materials provided with the distribution.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
+ * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
+ * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE.
+ */
+
+/* \summary: High-availability Seamless Redundancy (HSR) and
+ * Parallel Redundancy Protocol (PRP) printer */
+
+/* specification: https://webstore.iec.ch/publication/64423 */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "netdissect-stdinc.h"
+#include "netdissect.h"
+#include "extract.h"
+#include "addrtoname.h"
+
+/*
+ * HSR header
+ *     0                   1                   2                   3
+ *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |NetID|L|       LSDUsize        |         Sequence number       |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *     0                   1                   2                   3
+ *
+ * L = LanID
+ * LSDUsize = Link Service Data Unit size = size of the packet excluding MAC
+ * header, tags before the HSR tag (e.g. VLAN), and the HSR ethertype field.
+ * For PRP it includes the PRP suffix.
+ */
+
+#define HSR_HDR_LEN 6
+
+void hsr_print(netdissect_options *ndo, const u_char *bp, u_int length)
+{
+	int lanid, netid;
+	uint16_t lsdu_size;
+	uint16_t hdr;
+	uint32_t seq_nr;
+
+	ND_ICHECK_U(length, <, HSR_HDR_LEN);
+
+	hdr = GET_BE_U_2(bp);
+	lsdu_size = hdr & 0xFFF;
+	lanid = (hdr >> 12) & 0x1;
+	netid = hdr >> 13;
+
+	length -= 2;
+	bp += 2;
+	seq_nr = GET_BE_U_2(bp);
+
+	ND_PRINT("LSDUsize %u, SeqNr %u, LanId %s, NetId %u, ",
+		 lsdu_size, seq_nr, lanid ? "A" : "B", netid);
+
+	return;
+
+invalid:
+	nd_print_invalid(ndo);
+}
+