diff --git a/print-stp.c b/print-stp.c
new file mode 100644
index 0000000..4308ae0
--- /dev/null
+++ b/print-stp.c
@@ -0,0 +1,365 @@
+/*
+ * Copyright (c) 2000 Lennert Buytenhek
+ *
+ * This software may be distributed either under the terms of the
+ * BSD-style license that accompanies tcpdump or the GNU General
+ * Public License
+ *
+ * Format and print IEEE 802.1d spanning tree protocol packets.
+ * Contributed by Lennert Buytenhek <buytenh@gnu.org>
+ */
+
+#ifndef lint
+static const char rcsid[] _U_ =
+"@(#) $Header: /tcpdump/master/tcpdump/print-stp.c,v 1.13.2.7 2007/03/18 17:12:36 hannes Exp $";
+#endif
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <tcpdump-stdinc.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "interface.h"
+#include "addrtoname.h"
+#include "extract.h"
+
+#define	RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2) 
+/* STP timers are expressed in multiples of 1/256th second */
+#define STP_TIME_BASE 256
+#define STP_BPDU_MSTP_MIN_LEN 102
+
+struct stp_bpdu_ {
+    u_int8_t protocol_id[2];
+    u_int8_t protocol_version;
+    u_int8_t bpdu_type;
+    u_int8_t flags;
+    u_int8_t root_id[8];
+    u_int8_t root_path_cost[4];
+    u_int8_t bridge_id[8];
+    u_int8_t port_id[2];
+    u_int8_t message_age[2];
+    u_int8_t max_age[2];
+    u_int8_t hello_time[2];
+    u_int8_t forward_delay[2];
+    u_int8_t v1_length;
+};
+
+#define STP_PROTO_REGULAR 0x00
+#define STP_PROTO_RAPID   0x02
+#define STP_PROTO_MSTP    0x03
+
+struct tok stp_proto_values[] = {
+    { STP_PROTO_REGULAR, "802.1d" },
+    { STP_PROTO_RAPID, "802.1w" },
+    { STP_PROTO_MSTP, "802.1s" },
+    { 0, NULL}
+};
+
+#define STP_BPDU_TYPE_CONFIG      0x00
+#define STP_BPDU_TYPE_RSTP        0x02
+#define STP_BPDU_TYPE_TOPO_CHANGE 0x80
+
+struct tok stp_bpdu_flag_values[] = {
+    { 0x01, "Topology change" },
+    { 0x02, "Proposal" },
+    { 0x10, "Learn" },
+    { 0x20, "Forward" },
+    { 0x40, "Agreement" },
+    { 0x80, "Topology change ACK" },
+    { 0, NULL}
+};
+
+struct tok stp_bpdu_type_values[] = {
+    { STP_BPDU_TYPE_CONFIG, "Config" },
+    { STP_BPDU_TYPE_RSTP, "Rapid STP" },
+    { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" },
+    { 0, NULL}
+};
+
+struct tok rstp_obj_port_role_values[] = {
+    { 0x00, "Unknown" },
+    { 0x01, "Alternate" },
+    { 0x02, "Root" },
+    { 0x03, "Designated" },
+    { 0, NULL}
+};
+
+static char *
+stp_print_bridge_id(const u_char *p)
+{
+    static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")];
+
+    snprintf(bridge_id_str, sizeof(bridge_id_str),
+             "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
+             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
+
+    return bridge_id_str;
+}
+
+static void
+stp_print_config_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
+{
+    printf(", Flags [%s]",
+           bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
+
+    printf(", bridge-id %s.%04x, length %u",
+           stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
+           EXTRACT_16BITS(&stp_bpdu->port_id), length);
+
+    /* in non-verbose mode just print the bridge-id */
+    if (!vflag) {
+        return;
+    }
+
+    printf("\n\tmessage-age %.2fs, max-age %.2fs"
+           ", hello-time %.2fs, forwarding-delay %.2fs",
+           (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
+           (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
+           (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
+           (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
+
+    printf("\n\troot-id %s, root-pathcost %u",
+           stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
+           EXTRACT_32BITS(&stp_bpdu->root_path_cost));
+
+    /* Port role is only valid for 802.1w */
+    if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
+        printf(", port-role %s",
+               tok2str(rstp_obj_port_role_values, "Unknown",
+                       RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
+    }
+}
+
+/*
+ * MSTP packet format
+ * Ref. IEEE 802.1Q 2003 Ed. Section 14
+ *
+ * MSTP BPDU
+ *
+ * 2 -  bytes Protocol Id
+ * 1 -  byte  Protocol Ver. 
+ * 1 -  byte  BPDU tye
+ * 1 -  byte  Flags
+ * 8 -  bytes CIST Root Identifier
+ * 4 -  bytes CIST External Path Cost
+ * 8 -  bytes CIST Regional Root Identifier
+ * 2 -  bytes CIST Port Identifier
+ * 2 -  bytes Message Age
+ * 2 -  bytes Max age
+ * 2 -  bytes Hello Time
+ * 2 -  bytes Forward delay
+ * 1 -  byte  Version 1 length. Must be 0
+ * 2 -  bytes Version 3 length
+ * 1 -  byte  Config Identifier
+ * 32 - bytes Config Name
+ * 2 -  bytes Revision level
+ * 16 - bytes Config Digest [MD5]
+ * 4 -  bytes CIST Internal Root Path Cost
+ * 8 -  bytes CIST Bridge Identifier
+ * 1 -  byte  CIST Remaining Hops
+ * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes]
+ *
+ * MSTI Payload
+ *
+ * 1 - byte  MSTI flag
+ * 8 - bytes MSTI Regional Root Identifier
+ * 4 - bytes MSTI Regional Path Cost
+ * 1 - byte  MSTI Bridge Priority
+ * 1 - byte  MSTI Port Priority
+ * 1 - byte  MSTI Remaining Hops
+ */
+
+#define MST_BPDU_MSTI_LENGTH		    16
+#define MST_BPDU_CONFIG_INFO_LENGTH	    64
+
+/* Offsets of fields from the begginning for the packet */
+#define MST_BPDU_VER3_LEN_OFFSET	    36
+#define MST_BPDU_CONFIG_NAME_OFFSET	    39
+#define MST_BPDU_CONFIG_DIGEST_OFFSET	    73
+#define MST_BPDU_CIST_INT_PATH_COST_OFFSET  89
+#define MST_BPDU_CIST_BRIDGE_ID_OFFSET	    93
+#define MST_BPDU_CIST_REMAIN_HOPS_OFFSET    101
+#define MST_BPDU_MSTI_OFFSET		    102
+/* Offsets within  an MSTI */
+#define MST_BPDU_MSTI_ROOT_PRIO_OFFSET	    1
+#define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
+#define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET    13
+#define MST_BPDU_MSTI_PORT_PRIO_OFFSET	    14
+#define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET    15
+
+static void
+stp_print_mstp_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
+{
+    const u_char    *ptr;
+    u_int16_t	    v3len;
+    u_int16_t	    len;
+    u_int16_t	    msti;
+    u_int16_t	    offset;
+
+    ptr = (const u_char *)stp_bpdu;
+    printf(", CIST Flags [%s]",
+           bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
+
+    /*
+     * in non-verbose mode just print the flags. We dont read that much
+     * of the packet (DEFAULT_SNAPLEN) to print out cist bridge-id
+     */
+    if (!vflag) {
+        return;
+    }
+
+    printf(", CIST bridge-id %s.%04x, length %u",
+           stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET),
+           EXTRACT_16BITS(&stp_bpdu->port_id), length);
+
+
+    printf("\n\tmessage-age %.2fs, max-age %.2fs"
+           ", hello-time %.2fs, forwarding-delay %.2fs",
+           (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
+           (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
+           (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
+           (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
+
+    printf("\n\tCIST root-id %s, ext-pathcost %u int-pathcost %u",
+           stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
+           EXTRACT_32BITS(&stp_bpdu->root_path_cost),
+           EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET));
+
+    printf(", port-role %s",
+           tok2str(rstp_obj_port_role_values, "Unknown",
+                   RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
+
+    printf("\n\tCIST regional-root-id %s",
+           stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id));
+
+    printf("\n\tMSTP Configuration Name %s, revision %u, digest %08x%08x%08x%08x",
+           ptr + MST_BPDU_CONFIG_NAME_OFFSET,
+	   EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32),
+	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET),
+	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4),
+	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8),
+	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12));
+
+    printf("\n\tCIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]);
+
+    /* Dump all MSTI's */
+    v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET);
+    if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) {
+        len = v3len - MST_BPDU_CONFIG_INFO_LENGTH;
+        offset = MST_BPDU_MSTI_OFFSET;
+        while (len >= MST_BPDU_MSTI_LENGTH) {
+            msti = EXTRACT_16BITS(ptr + offset +
+                                  MST_BPDU_MSTI_ROOT_PRIO_OFFSET);
+            msti = msti & 0x0FFF;
+
+            printf("\n\tMSTI %d, Flags [%s], port-role %s", 
+                   msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]),
+                   tok2str(rstp_obj_port_role_values, "Unknown",
+                           RSTP_EXTRACT_PORT_ROLE(ptr[offset])));
+            printf("\n\t\tMSTI regional-root-id %s, pathcost %u",
+                   stp_print_bridge_id(ptr + offset +
+                                       MST_BPDU_MSTI_ROOT_PRIO_OFFSET),
+                   EXTRACT_32BITS(ptr + offset +
+                                  MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET));
+            printf("\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d",
+                   ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4,
+                   ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4,
+                   ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET]);
+
+            len -= MST_BPDU_MSTI_LENGTH;
+            offset += MST_BPDU_MSTI_LENGTH;
+        }
+    }
+}
+
+/*
+ * Print 802.1d / 802.1w / 802.1q (mstp) packets.
+ */
+void
+stp_print(const u_char *p, u_int length)
+{
+    const struct stp_bpdu_ *stp_bpdu;
+    u_int16_t              mstp_len;
+    
+    stp_bpdu = (struct stp_bpdu_*)p;
+
+    /* Minimum STP Frame size. */
+    if (length < 4)
+        goto trunc;
+        
+    if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
+        printf("unknown STP version, length %u", length);
+        return;
+    }
+
+    printf("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
+                         stp_bpdu->protocol_version));
+
+    switch (stp_bpdu->protocol_version) {
+    case STP_PROTO_REGULAR:
+    case STP_PROTO_RAPID:
+    case STP_PROTO_MSTP:
+        break;
+    default:
+        return;
+    }
+
+    printf(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
+                           stp_bpdu->bpdu_type));
+
+    switch (stp_bpdu->bpdu_type) {
+    case STP_BPDU_TYPE_CONFIG:
+        if (length < sizeof(struct stp_bpdu_) - 1) {
+            goto trunc;
+        }
+        stp_print_config_bpdu(stp_bpdu, length);
+        break;
+
+    case STP_BPDU_TYPE_RSTP:
+        if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
+            if (length < sizeof(struct stp_bpdu_)) {
+                goto trunc;
+            }
+            stp_print_config_bpdu(stp_bpdu, length);
+        } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP) {
+            if (length < STP_BPDU_MSTP_MIN_LEN) {
+                goto trunc;
+            }
+            if (stp_bpdu->v1_length != 0) {
+                /* FIX ME: Emit a message here ? */
+                goto trunc;
+            }
+            /* Validate v3 length */
+            mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET);
+            mstp_len += 2;  /* length encoding itself is 2 bytes */
+            if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
+                goto trunc;
+            }
+            stp_print_mstp_bpdu(stp_bpdu, length);
+        }
+        break;
+
+    case STP_BPDU_TYPE_TOPO_CHANGE:
+        /* always empty message - just break out */
+        break;
+
+    default:
+        break;
+    }
+
+    return;
+ trunc:
+    printf("[|stp %d]", length);
+}
+
+/*
+ * Local Variables:
+ * c-style: whitesmith
+ * c-basic-offset: 4
+ * End:
+ */