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/*
 * Decode and print Zephyr packets.
 *
 *      http://web.mit.edu/zephyr/doc/protocol
 *
 * Copyright (c) 2001 Nickolai Zeldovich <kolya@MIT.EDU>
 * All rights reserved.
 *
 * 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.
 * The name of the author(s) may not be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.  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.
 */

#define NETDISSECT_REWORKED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "interface.h"

struct z_packet {
    char *version;
    int numfields;
    int kind;
    char *uid;
    int port;
    int auth;
    int authlen;
    char *authdata;
    char *class;
    char *inst;
    char *opcode;
    char *sender;
    const char *recipient;
    char *format;
    int cksum;
    int multi;
    char *multi_uid;
    /* Other fields follow here.. */
};

enum z_packet_type {
    Z_PACKET_UNSAFE = 0,
    Z_PACKET_UNACKED,
    Z_PACKET_ACKED,
    Z_PACKET_HMACK,
    Z_PACKET_HMCTL,
    Z_PACKET_SERVACK,
    Z_PACKET_SERVNAK,
    Z_PACKET_CLIENTACK,
    Z_PACKET_STAT
};

static const struct tok z_types[] = {
    { Z_PACKET_UNSAFE,          "unsafe" },
    { Z_PACKET_UNACKED,         "unacked" },
    { Z_PACKET_ACKED,           "acked" },
    { Z_PACKET_HMACK,           "hm-ack" },
    { Z_PACKET_HMCTL,           "hm-ctl" },
    { Z_PACKET_SERVACK,         "serv-ack" },
    { Z_PACKET_SERVNAK,         "serv-nak" },
    { Z_PACKET_CLIENTACK,       "client-ack" },
    { Z_PACKET_STAT,            "stat" }
};

static char z_buf[256];

static char *
parse_field(netdissect_options *ndo, char **pptr, int *len)
{
    char *s;

    if (*len <= 0 || !pptr || !*pptr)
        return NULL;
    if (*pptr > (char *) ndo->ndo_snapend)
        return NULL;

    s = *pptr;
    while (*pptr <= (char *) ndo->ndo_snapend && *len >= 0 && **pptr) {
        (*pptr)++;
        (*len)--;
    }
    (*pptr)++;
    (*len)--;
    if (*len < 0 || *pptr > (char *) ndo->ndo_snapend)
        return NULL;
    return s;
}

static const char *
z_triple(char *class, char *inst, const char *recipient)
{
    if (!*recipient)
        recipient = "*";
    snprintf(z_buf, sizeof(z_buf), "<%s,%s,%s>", class, inst, recipient);
    z_buf[sizeof(z_buf)-1] = '\0';
    return z_buf;
}

static const char *
str_to_lower(char *string)
{
    strncpy(z_buf, string, sizeof(z_buf));
    z_buf[sizeof(z_buf)-1] = '\0';

    string = z_buf;
    while (*string) {
        *string = tolower((unsigned char)(*string));
        string++;
    }

    return z_buf;
}

void
zephyr_print(netdissect_options *ndo, const u_char *cp, int length)
{
    struct z_packet z;
    char *parse = (char *) cp;
    int parselen = length;
    char *s;
    int lose = 0;

    /* squelch compiler warnings */

    z.kind = 0;
    z.class = 0;
    z.inst = 0;
    z.opcode = 0;
    z.sender = 0;
    z.recipient = 0;

#define PARSE_STRING                            \
        s = parse_field(ndo, &parse, &parselen);        \
        if (!s) lose = 1;

#define PARSE_FIELD_INT(field)                  \
        PARSE_STRING                            \
        if (!lose) field = strtol(s, 0, 16);

#define PARSE_FIELD_STR(field)                  \
        PARSE_STRING                            \
        if (!lose) field = s;

    PARSE_FIELD_STR(z.version);
    if (lose) return;
    if (strncmp(z.version, "ZEPH", 4))
        return;

    PARSE_FIELD_INT(z.numfields);
    PARSE_FIELD_INT(z.kind);
    PARSE_FIELD_STR(z.uid);
    PARSE_FIELD_INT(z.port);
    PARSE_FIELD_INT(z.auth);
    PARSE_FIELD_INT(z.authlen);
    PARSE_FIELD_STR(z.authdata);
    PARSE_FIELD_STR(z.class);
    PARSE_FIELD_STR(z.inst);
    PARSE_FIELD_STR(z.opcode);
    PARSE_FIELD_STR(z.sender);
    PARSE_FIELD_STR(z.recipient);
    PARSE_FIELD_STR(z.format);
    PARSE_FIELD_INT(z.cksum);
    PARSE_FIELD_INT(z.multi);
    PARSE_FIELD_STR(z.multi_uid);

    if (lose) {
        ND_PRINT((ndo, " [|zephyr] (%d)", length));
        return;
    }

    ND_PRINT((ndo, " zephyr"));
    if (strncmp(z.version+4, "0.2", 3)) {
        ND_PRINT((ndo, " v%s", z.version+4));
        return;
    }

    ND_PRINT((ndo, " %s", tok2str(z_types, "type %d", z.kind)));
    if (z.kind == Z_PACKET_SERVACK) {
        /* Initialization to silence warnings */
        char *ackdata = NULL;
        PARSE_FIELD_STR(ackdata);
        if (!lose && strcmp(ackdata, "SENT"))
            ND_PRINT((ndo, "/%s", str_to_lower(ackdata)));
    }
    if (*z.sender) ND_PRINT((ndo, " %s", z.sender));

    if (!strcmp(z.class, "USER_LOCATE")) {
        if (!strcmp(z.opcode, "USER_HIDE"))
            ND_PRINT((ndo, " hide"));
        else if (!strcmp(z.opcode, "USER_UNHIDE"))
            ND_PRINT((ndo, " unhide"));
        else
            ND_PRINT((ndo, " locate %s", z.inst));
        return;
    }

    if (!strcmp(z.class, "ZEPHYR_ADMIN")) {
        ND_PRINT((ndo, " zephyr-admin %s", str_to_lower(z.opcode)));
        return;
    }

    if (!strcmp(z.class, "ZEPHYR_CTL")) {
        if (!strcmp(z.inst, "CLIENT")) {
            if (!strcmp(z.opcode, "SUBSCRIBE") ||
                !strcmp(z.opcode, "SUBSCRIBE_NODEFS") ||
                !strcmp(z.opcode, "UNSUBSCRIBE")) {

                ND_PRINT((ndo, " %ssub%s", strcmp(z.opcode, "SUBSCRIBE") ? "un" : "",
                                   strcmp(z.opcode, "SUBSCRIBE_NODEFS") ? "" :
                                                                   "-nodefs"));
                if (z.kind != Z_PACKET_SERVACK) {
                    /* Initialization to silence warnings */
                    char *c = NULL, *i = NULL, *r = NULL;
                    PARSE_FIELD_STR(c);
                    PARSE_FIELD_STR(i);
                    PARSE_FIELD_STR(r);
                    if (!lose) ND_PRINT((ndo, " %s", z_triple(c, i, r)));
                }
                return;
            }

            if (!strcmp(z.opcode, "GIMME")) {
                ND_PRINT((ndo, " ret"));
                return;
            }

            if (!strcmp(z.opcode, "GIMMEDEFS")) {
                ND_PRINT((ndo, " gimme-defs"));
                return;
            }

            if (!strcmp(z.opcode, "CLEARSUB")) {
                ND_PRINT((ndo, " clear-subs"));
                return;
            }

            ND_PRINT((ndo, " %s", str_to_lower(z.opcode)));
            return;
        }

        if (!strcmp(z.inst, "HM")) {
            ND_PRINT((ndo, " %s", str_to_lower(z.opcode)));
            return;
        }

        if (!strcmp(z.inst, "REALM")) {
            if (!strcmp(z.opcode, "ADD_SUBSCRIBE"))
                ND_PRINT((ndo, " realm add-subs"));
            if (!strcmp(z.opcode, "REQ_SUBSCRIBE"))
                ND_PRINT((ndo, " realm req-subs"));
            if (!strcmp(z.opcode, "RLM_SUBSCRIBE"))
                ND_PRINT((ndo, " realm rlm-sub"));
            if (!strcmp(z.opcode, "RLM_UNSUBSCRIBE"))
                ND_PRINT((ndo, " realm rlm-unsub"));
            return;
        }
    }

    if (!strcmp(z.class, "HM_CTL")) {
        ND_PRINT((ndo, " hm_ctl %s", str_to_lower(z.inst)));
        ND_PRINT((ndo, " %s", str_to_lower(z.opcode)));
        return;
    }

    if (!strcmp(z.class, "HM_STAT")) {
        if (!strcmp(z.inst, "HMST_CLIENT") && !strcmp(z.opcode, "GIMMESTATS")) {
            ND_PRINT((ndo, " get-client-stats"));
            return;
        }
    }

    if (!strcmp(z.class, "WG_CTL")) {
        ND_PRINT((ndo, " wg_ctl %s", str_to_lower(z.inst)));
        ND_PRINT((ndo, " %s", str_to_lower(z.opcode)));
        return;
    }

    if (!strcmp(z.class, "LOGIN")) {
        if (!strcmp(z.opcode, "USER_FLUSH")) {
            ND_PRINT((ndo, " flush_locs"));
            return;
        }

        if (!strcmp(z.opcode, "NONE") ||
            !strcmp(z.opcode, "OPSTAFF") ||
            !strcmp(z.opcode, "REALM-VISIBLE") ||
            !strcmp(z.opcode, "REALM-ANNOUNCED") ||
            !strcmp(z.opcode, "NET-VISIBLE") ||
            !strcmp(z.opcode, "NET-ANNOUNCED")) {
            ND_PRINT((ndo, " set-exposure %s", str_to_lower(z.opcode)));
            return;
        }
    }

    if (!*z.recipient)
        z.recipient = "*";

    ND_PRINT((ndo, " to %s", z_triple(z.class, z.inst, z.recipient)));
    if (*z.opcode)
        ND_PRINT((ndo, " op %s", z.opcode));
}