xref: /freebsd/contrib/tcpdump/print-syslog.c (revision 5f4c09dd85bff675e0ca63c55ea3c517e0fddfcc)
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 /* \summary: Syslog protocol printer */
18 /* specification: RFC 3164 (not RFC 5424) */
19 
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23 
24 #include "netdissect-stdinc.h"
25 
26 #include "netdissect.h"
27 #include "extract.h"
28 
29 
30 /*
31  * tokenlists and #defines taken from Ethereal - Network traffic analyzer
32  * by Gerald Combs <gerald@ethereal.com>
33  */
34 
35 #define SYSLOG_SEVERITY_MASK 0x0007  /* 0000 0000 0000 0111 */
36 #define SYSLOG_FACILITY_MASK 0x03f8  /* 0000 0011 1111 1000 */
37 #define SYSLOG_MAX_DIGITS 3 /* The maximum number of priority digits to read in. */
38 
39 static const struct tok syslog_severity_values[] = {
40   { 0,      "emergency" },
41   { 1,      "alert" },
42   { 2,      "critical" },
43   { 3,      "error" },
44   { 4,      "warning" },
45   { 5,      "notice" },
46   { 6,      "info" },
47   { 7,      "debug" },
48   { 0, NULL },
49 };
50 
51 static const struct tok syslog_facility_values[] = {
52   { 0,     "kernel" },
53   { 1,     "user" },
54   { 2,     "mail" },
55   { 3,     "daemon" },
56   { 4,     "auth" },
57   { 5,     "syslog" },
58   { 6,     "lpr" },
59   { 7,     "news" },
60   { 8,     "uucp" },
61   { 9,     "cron" },
62   { 10,    "authpriv" },
63   { 11,    "ftp" },
64   { 12,    "ntp" },
65   { 13,    "security" },
66   { 14,    "console" },
67   { 15,    "cron" },
68   { 16,    "local0" },
69   { 17,    "local1" },
70   { 18,    "local2" },
71   { 19,    "local3" },
72   { 20,    "local4" },
73   { 21,    "local5" },
74   { 22,    "local6" },
75   { 23,    "local7" },
76   { 0, NULL },
77 };
78 
79 void
80 syslog_print(netdissect_options *ndo,
81              const u_char *pptr, u_int len)
82 {
83     uint16_t msg_off = 0;
84     uint16_t pri = 0;
85     uint16_t facility,severity;
86 
87     ndo->ndo_protocol = "syslog";
88     /* extract decimal figures that are
89      * encapsulated within < > tags
90      * based on this decimal figure extract the
91      * severity and facility values
92      */
93 
94     if (GET_U_1(pptr) != '<')
95         goto invalid;
96     msg_off++;
97 
98     while (msg_off <= SYSLOG_MAX_DIGITS &&
99            GET_U_1(pptr + msg_off) >= '0' &&
100            GET_U_1(pptr + msg_off) <= '9') {
101         pri = pri * 10 + (GET_U_1(pptr + msg_off) - '0');
102         msg_off++;
103     }
104 
105     if (GET_U_1(pptr + msg_off) != '>')
106         goto invalid;
107     msg_off++;
108 
109     facility = (pri & SYSLOG_FACILITY_MASK) >> 3;
110     severity = pri & SYSLOG_SEVERITY_MASK;
111 
112     if (ndo->ndo_vflag < 1 )
113     {
114         ND_PRINT("SYSLOG %s.%s, length: %u",
115                tok2str(syslog_facility_values, "unknown (%u)", facility),
116                tok2str(syslog_severity_values, "unknown (%u)", severity),
117                len);
118         return;
119     }
120 
121     ND_PRINT("SYSLOG, length: %u\n\tFacility %s (%u), Severity %s (%u)\n\tMsg: ",
122            len,
123            tok2str(syslog_facility_values, "unknown (%u)", facility),
124            facility,
125            tok2str(syslog_severity_values, "unknown (%u)", severity),
126            severity);
127 
128     /* print the syslog text in verbose mode */
129     /*
130      * RFC 3164 Section 4.1.3: "There is no ending delimiter to this part.
131      * The MSG part of the syslog packet MUST contain visible (printing)
132      * characters."
133      *
134      * RFC 5424 Section 8.2: "This document does not impose any mandatory
135      * restrictions on the MSG or PARAM-VALUE content.  As such, they MAY
136      * contain control characters, including the NUL character."
137      *
138      * Hence, to aid in protocol debugging, print the full MSG without
139      * beautification to make it clear what was transmitted on the wire.
140      */
141     if (len > msg_off)
142         (void)nd_printn(ndo, pptr + msg_off, len - msg_off, NULL);
143 
144     if (ndo->ndo_vflag > 1)
145         print_unknown_data(ndo, pptr, "\n\t", len);
146     return;
147 
148 invalid:
149     nd_print_invalid(ndo);
150 }
151