tcpdump  4.99.1
About: tcpdump is a tool for network monitoring and data acquisition.
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print-pppoe.c
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1 /*
2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3  * The Regents of the University of California. All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  *
21  * Original code by Greg Stark <gsstark@mit.edu>
22  */
23 
24 /* \summary: PPP-over-Ethernet (PPPoE) printer */
25 
26 #ifdef HAVE_CONFIG_H
27 #include <config.h>
28 #endif
29 
30 #include "netdissect-stdinc.h"
31 
32 #include "netdissect-ctype.h"
33 
34 #define ND_LONGJMP_FROM_TCHECK
35 #include "netdissect.h"
36 #include "extract.h"
37 
38 /* Codes */
39 enum {
40  PPPOE_PADI = 0x09,
41  PPPOE_PADO = 0x07,
42  PPPOE_PADR = 0x19,
43  PPPOE_PADS = 0x65,
44  PPPOE_PADT = 0xa7
45 };
46 
47 static const struct tok pppoecode2str[] = {
48  { PPPOE_PADI, "PADI" },
49  { PPPOE_PADO, "PADO" },
50  { PPPOE_PADR, "PADR" },
51  { PPPOE_PADS, "PADS" },
52  { PPPOE_PADT, "PADT" },
53  { 0, "" }, /* PPP Data */
54  { 0, NULL }
55 };
56 
57 /* Tags */
58 enum {
59  PPPOE_EOL = 0,
61  PPPOE_AC_NAME = 0x0102,
62  PPPOE_HOST_UNIQ = 0x0103,
63  PPPOE_AC_COOKIE = 0x0104,
64  PPPOE_VENDOR = 0x0105,
65  PPPOE_RELAY_SID = 0x0110,
69  PPPOE_GENERIC_ERROR = 0x0203
70 };
71 
72 static const struct tok pppoetag2str[] = {
73  { PPPOE_EOL, "EOL" },
74  { PPPOE_SERVICE_NAME, "Service-Name" },
75  { PPPOE_AC_NAME, "AC-Name" },
76  { PPPOE_HOST_UNIQ, "Host-Uniq" },
77  { PPPOE_AC_COOKIE, "AC-Cookie" },
78  { PPPOE_VENDOR, "Vendor-Specific" },
79  { PPPOE_RELAY_SID, "Relay-Session-ID" },
80  { PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
81  { PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
82  { PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
83  { PPPOE_GENERIC_ERROR, "Generic-Error" },
84  { 0, NULL }
85 };
86 
87 #define PPPOE_HDRLEN 6
88 #define MAXTAGPRINT 80
89 
90 void
91 pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
92 {
93  ndo->ndo_protocol = "pppoe";
94  ndo->ndo_ll_hdr_len += pppoe_print(ndo, p, h->len);
95 }
96 
97 u_int
98 pppoe_print(netdissect_options *ndo, const u_char *bp, u_int length)
99 {
100  uint16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
101  u_int pppoe_length;
102  const u_char *pppoe_packet, *pppoe_payload;
103 
104  ndo->ndo_protocol = "pppoe";
105  if (length < PPPOE_HDRLEN) {
106  ND_PRINT(" (length %u < %u)", length, PPPOE_HDRLEN);
107  goto invalid;
108  }
109  length -= PPPOE_HDRLEN;
110  pppoe_packet = bp;
111  ND_TCHECK_LEN(pppoe_packet, PPPOE_HDRLEN);
112  pppoe_ver = (GET_U_1(pppoe_packet) & 0xF0) >> 4;
113  pppoe_type = (GET_U_1(pppoe_packet) & 0x0F);
114  pppoe_code = GET_U_1(pppoe_packet + 1);
115  pppoe_sessionid = GET_BE_U_2(pppoe_packet + 2);
116  pppoe_length = GET_BE_U_2(pppoe_packet + 4);
117  pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
118 
119  if (pppoe_ver != 1) {
120  ND_PRINT(" [ver %u]",pppoe_ver);
121  }
122  if (pppoe_type != 1) {
123  ND_PRINT(" [type %u]",pppoe_type);
124  }
125 
126  ND_PRINT("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
127  if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
128  ND_PRINT(" [len %u!]",pppoe_length);
129  }
130  if (pppoe_length > length) {
131  ND_PRINT(" [len %u > %u!]", pppoe_length, length);
132  pppoe_length = length;
133  }
134  if (pppoe_sessionid) {
135  ND_PRINT(" [ses 0x%x]", pppoe_sessionid);
136  }
137 
138  if (pppoe_code) {
139  /* PPP session packets don't contain tags */
140  u_short tag_type = 0xffff, tag_len;
141  const u_char *p = pppoe_payload;
142 
143  /*
144  * loop invariant:
145  * p points to current tag,
146  * tag_type is previous tag or 0xffff for first iteration
147  */
148  while (tag_type && p < pppoe_payload + pppoe_length) {
149  tag_type = GET_BE_U_2(p);
150  tag_len = GET_BE_U_2(p + 2);
151  p += 4;
152  /* p points to tag_value */
153 
154  if (tag_len) {
155  unsigned ascii_count = 0, garbage_count = 0;
156  const u_char *v;
157  char tag_str[MAXTAGPRINT];
158  unsigned tag_str_len = 0;
159 
160  /* TODO print UTF-8 decoded text */
161  ND_TCHECK_LEN(p, tag_len);
162  for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
163  if (ND_ASCII_ISPRINT(GET_U_1(v))) {
164  tag_str[tag_str_len++] = GET_U_1(v);
165  ascii_count++;
166  } else {
167  tag_str[tag_str_len++] = '.';
168  garbage_count++;
169  }
170  tag_str[tag_str_len] = 0;
171 
172  if (ascii_count > garbage_count) {
173  ND_PRINT(" [%s \"%*.*s\"]",
174  tok2str(pppoetag2str, "TAG-0x%x", tag_type),
175  (int)tag_str_len,
176  (int)tag_str_len,
177  tag_str);
178  } else {
179  /* Print hex, not fast to abuse printf but this doesn't get used much */
180  ND_PRINT(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type));
181  for (v=p; v<p+tag_len; v++) {
182  ND_PRINT("%02X", GET_U_1(v));
183  }
184  ND_PRINT("]");
185  }
186 
187 
188  } else
189  ND_PRINT(" [%s]", tok2str(pppoetag2str,
190  "TAG-0x%x", tag_type));
191 
192  p += tag_len;
193  /* p points to next tag */
194  }
195  return PPPOE_HDRLEN;
196  } else {
197  /* PPPoE data */
198  ND_PRINT(" ");
199  return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length));
200  }
201  /* NOTREACHED */
202 
203 invalid:
204  nd_print_invalid(ndo);
205  return 0;
206 }
#define GET_BE_U_2(p)
Definition: extract.h:875
#define GET_U_1(p)
Definition: extract.h:872
#define ND_ASCII_ISPRINT(c)
#define ND_TCHECK_LEN(p, l)
Definition: netdissect.h:368
const char * tok2str(const struct tok *, const char *, u_int)
Definition: util-print.c:485
void nd_print_invalid(netdissect_options *)
Definition: util-print.c:429
#define ND_PRINT(...)
Definition: netdissect.h:385
u_int ppp_print(netdissect_options *, const u_char *, u_int)
Definition: print-ppp.c:1509
@ PPPOE_HOST_UNIQ
Definition: print-pppoe.c:62
@ PPPOE_AC_COOKIE
Definition: print-pppoe.c:63
@ PPPOE_SERVICE_NAME_ERROR
Definition: print-pppoe.c:67
@ PPPOE_MAX_PAYLOAD
Definition: print-pppoe.c:66
@ PPPOE_AC_SYSTEM_ERROR
Definition: print-pppoe.c:68
@ PPPOE_RELAY_SID
Definition: print-pppoe.c:65
@ PPPOE_EOL
Definition: print-pppoe.c:59
@ PPPOE_AC_NAME
Definition: print-pppoe.c:61
@ PPPOE_SERVICE_NAME
Definition: print-pppoe.c:60
@ PPPOE_VENDOR
Definition: print-pppoe.c:64
@ PPPOE_GENERIC_ERROR
Definition: print-pppoe.c:69
void pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
Definition: print-pppoe.c:91
#define PPPOE_HDRLEN
Definition: print-pppoe.c:87
#define MAXTAGPRINT
Definition: print-pppoe.c:88
static const struct tok pppoecode2str[]
Definition: print-pppoe.c:47
u_int pppoe_print(netdissect_options *ndo, const u_char *bp, u_int length)
Definition: print-pppoe.c:98
static const struct tok pppoetag2str[]
Definition: print-pppoe.c:72
@ PPPOE_PADO
Definition: print-pppoe.c:41
@ PPPOE_PADI
Definition: print-pppoe.c:40
@ PPPOE_PADT
Definition: print-pppoe.c:44
@ PPPOE_PADS
Definition: print-pppoe.c:43
@ PPPOE_PADR
Definition: print-pppoe.c:42
const char * ndo_protocol
Definition: netdissect.h:218
u_int v
Definition: netdissect.h:139