print-syslog.c revision 1.9 
1/*
2 * Copyright (c) 1998-2004  Hannes Gredler <hannes@gredler.at>
3 *      The TCPDUMP project
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code
7 * distributions retain the above copyright notice and this paragraph
8 * in its entirety, and (2) distributions including binary code include
9 * the above copyright notice and this paragraph in its entirety in
10 * the documentation or other materials provided with the distribution.
11 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
12 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
13 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
14 * FOR A PARTICULAR PURPOSE.
15 */
16
17#include <sys/cdefs.h>
18#ifndef lint
19__RCSID("$NetBSD: print-syslog.c,v 1.9 2023/08/17 20:19:40 christos Exp $");
20#endif
21
22/* \summary: Syslog protocol printer */
23/* specification: RFC 3164 (not RFC 5424) */
24
25#ifdef HAVE_CONFIG_H
26#include <config.h>
27#endif
28
29#include "netdissect-stdinc.h"
30
31#include "netdissect.h"
32#include "extract.h"
33
34
35/*
36 * tokenlists and #defines taken from Ethereal - Network traffic analyzer
37 * by Gerald Combs <gerald@ethereal.com>
38 */
39
40#define SYSLOG_SEVERITY_MASK 0x0007  /* 0000 0000 0000 0111 */
41#define SYSLOG_FACILITY_MASK 0x03f8  /* 0000 0011 1111 1000 */
42#define SYSLOG_MAX_DIGITS 3 /* The maximum number of priority digits to read in. */
43
44static const struct tok syslog_severity_values[] = {
45  { 0,      "emergency" },
46  { 1,      "alert" },
47  { 2,      "critical" },
48  { 3,      "error" },
49  { 4,      "warning" },
50  { 5,      "notice" },
51  { 6,      "info" },
52  { 7,      "debug" },
53  { 0, NULL },
54};
55
56static const struct tok syslog_facility_values[] = {
57  { 0,     "kernel" },
58  { 1,     "user" },
59  { 2,     "mail" },
60  { 3,     "daemon" },
61  { 4,     "auth" },
62  { 5,     "syslog" },
63  { 6,     "lpr" },
64  { 7,     "news" },
65  { 8,     "uucp" },
66  { 9,     "cron" },
67  { 10,    "authpriv" },
68  { 11,    "ftp" },
69  { 12,    "ntp" },
70  { 13,    "security" },
71  { 14,    "console" },
72  { 15,    "cron" },
73  { 16,    "local0" },
74  { 17,    "local1" },
75  { 18,    "local2" },
76  { 19,    "local3" },
77  { 20,    "local4" },
78  { 21,    "local5" },
79  { 22,    "local6" },
80  { 23,    "local7" },
81  { 0, NULL },
82};
83
84void
85syslog_print(netdissect_options *ndo,
86             const u_char *pptr, u_int len)
87{
88    uint16_t msg_off = 0;
89    uint16_t pri = 0;
90    uint16_t facility,severity;
91
92    ndo->ndo_protocol = "syslog";
93    /* extract decimal figures that are
94     * encapsulated within < > tags
95     * based on this decimal figure extract the
96     * severity and facility values
97     */
98
99    if (GET_U_1(pptr) != '<')
100        goto invalid;
101    msg_off++;
102
103    while (msg_off <= SYSLOG_MAX_DIGITS &&
104           GET_U_1(pptr + msg_off) >= '0' &&
105           GET_U_1(pptr + msg_off) <= '9') {
106        pri = pri * 10 + (GET_U_1(pptr + msg_off) - '0');
107        msg_off++;
108    }
109
110    if (GET_U_1(pptr + msg_off) != '>')
111        goto invalid;
112    msg_off++;
113
114    facility = (pri & SYSLOG_FACILITY_MASK) >> 3;
115    severity = pri & SYSLOG_SEVERITY_MASK;
116
117    if (ndo->ndo_vflag < 1 )
118    {
119        ND_PRINT("SYSLOG %s.%s, length: %u",
120               tok2str(syslog_facility_values, "unknown (%u)", facility),
121               tok2str(syslog_severity_values, "unknown (%u)", severity),
122               len);
123        return;
124    }
125
126    ND_PRINT("SYSLOG, length: %u\n\tFacility %s (%u), Severity %s (%u)\n\tMsg: ",
127           len,
128           tok2str(syslog_facility_values, "unknown (%u)", facility),
129           facility,
130           tok2str(syslog_severity_values, "unknown (%u)", severity),
131           severity);
132
133    /* print the syslog text in verbose mode */
134    /*
135     * RFC 3164 Section 4.1.3: "There is no ending delimiter to this part.
136     * The MSG part of the syslog packet MUST contain visible (printing)
137     * characters."
138     *
139     * RFC 5424 Section 8.2: "This document does not impose any mandatory
140     * restrictions on the MSG or PARAM-VALUE content.  As such, they MAY
141     * contain control characters, including the NUL character."
142     *
143     * Hence, to aid in protocol debugging, print the full MSG without
144     * beautification to make it clear what was transmitted on the wire.
145     */
146    if (len > msg_off)
147        (void)nd_printn(ndo, pptr + msg_off, len - msg_off, NULL);
148
149    if (ndo->ndo_vflag > 1)
150        print_unknown_data(ndo, pptr, "\n\t", len);
151    return;
152
153invalid:
154    nd_print_invalid(ndo);
155}
156