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6bab039 @saghul Added support for parsing NAPTR records
saghul authored
1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 * Copyright (C) 2009 by Jakub Hrozek <jhrozek@redhat.com>
4 *
5 * Permission to use, copy, modify, and distribute this
6 * software and its documentation for any purpose and without
7 * fee is hereby granted, provided that the above copyright
8 * notice appear in all copies and that both that copyright
9 * notice and this permission notice appear in supporting
10 * documentation, and that the name of M.I.T. not be used in
11 * advertising or publicity pertaining to distribution of the
12 * software without specific, written prior permission.
13 * M.I.T. makes no representations about the suitability of
14 * this software for any purpose. It is provided "as is"
15 * without express or implied warranty.
16 */
17
18 #include "ares_setup.h"
19
20 #ifdef HAVE_NETINET_IN_H
21 # include <netinet/in.h>
22 #endif
23 #ifdef HAVE_NETDB_H
24 # include <netdb.h>
25 #endif
26 #ifdef HAVE_ARPA_INET_H
27 # include <arpa/inet.h>
28 #endif
29 #ifdef HAVE_ARPA_NAMESER_H
30 # include <arpa/nameser.h>
31 #else
32 # include "nameser.h"
33 #endif
34 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
35 # include <arpa/nameser_compat.h>
36 #endif
37
38 #include "ares.h"
39 #include "ares_dns.h"
40 #include "ares_data.h"
41 #include "ares_private.h"
42
43 /* AIX portability check */
44 #ifndef T_NAPTR
45 #define T_NAPTR 35 /* naming authority pointer */
46 #endif
47
48 int
49 ares_parse_naptr_reply (const unsigned char *abuf, int alen,
50 struct ares_naptr_reply **naptr_out)
51 {
52 unsigned int qdcount, ancount, i;
53 const unsigned char *aptr, *vptr;
54 int status, rr_type, rr_class, rr_len;
55 long len;
56 char *hostname = NULL, *rr_name = NULL;
57 struct ares_naptr_reply *naptr_head = NULL;
58 struct ares_naptr_reply *naptr_last = NULL;
59 struct ares_naptr_reply *naptr_curr;
60
61 /* Set *naptr_out to NULL for all failure cases. */
62 *naptr_out = NULL;
63
64 /* Give up if abuf doesn't have room for a header. */
65 if (alen < HFIXEDSZ)
66 return ARES_EBADRESP;
67
68 /* Fetch the question and answer count from the header. */
69 qdcount = DNS_HEADER_QDCOUNT (abuf);
70 ancount = DNS_HEADER_ANCOUNT (abuf);
71 if (qdcount != 1)
72 return ARES_EBADRESP;
73 if (ancount == 0)
74 return ARES_ENODATA;
75
76 /* Expand the name from the question, and skip past the question. */
77 aptr = abuf + HFIXEDSZ;
78 status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
79 if (status != ARES_SUCCESS)
80 return status;
81
82 if (aptr + len + QFIXEDSZ > abuf + alen)
83 {
84 free (hostname);
85 return ARES_EBADRESP;
86 }
87 aptr += len + QFIXEDSZ;
88
89 /* Examine each answer resource record (RR) in turn. */
90 for (i = 0; i < ancount; i++)
91 {
92 /* Decode the RR up to the data field. */
93 status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
94 if (status != ARES_SUCCESS)
95 {
96 break;
97 }
98 aptr += len;
99 if (aptr + RRFIXEDSZ > abuf + alen)
100 {
101 status = ARES_EBADRESP;
102 break;
103 }
104 rr_type = DNS_RR_TYPE (aptr);
105 rr_class = DNS_RR_CLASS (aptr);
106 rr_len = DNS_RR_LEN (aptr);
107 aptr += RRFIXEDSZ;
148c8e0 protocol parsing: check input data stricter
Patrick Valsecchi authored
108 if (aptr + rr_len > abuf + alen)
109 {
110 status = ARES_EBADRESP;
111 break;
112 }
6bab039 @saghul Added support for parsing NAPTR records
saghul authored
113
114 /* Check if we are really looking at a NAPTR record */
115 if (rr_class == C_IN && rr_type == T_NAPTR)
116 {
117 /* parse the NAPTR record itself */
118
119 /* Allocate storage for this NAPTR answer appending it to the list */
120 naptr_curr = ares_malloc_data(ARES_DATATYPE_NAPTR_REPLY);
121 if (!naptr_curr)
122 {
123 status = ARES_ENOMEM;
124 break;
125 }
126 if (naptr_last)
127 {
128 naptr_last->next = naptr_curr;
129 }
130 else
131 {
132 naptr_head = naptr_curr;
133 }
134 naptr_last = naptr_curr;
135
136 vptr = aptr;
137 naptr_curr->order = DNS__16BIT(vptr);
138 vptr += sizeof(unsigned short);
139 naptr_curr->preference = DNS__16BIT(vptr);
140 vptr += sizeof(unsigned short);
141
142 status = ares_expand_string(vptr, abuf, alen, &naptr_curr->flags, &len);
143 if (status != ARES_SUCCESS)
144 break;
145 vptr += len;
146
147 status = ares_expand_string(vptr, abuf, alen, &naptr_curr->service, &len);
148 if (status != ARES_SUCCESS)
149 break;
150 vptr += len;
151
152 status = ares_expand_string(vptr, abuf, alen, &naptr_curr->regexp, &len);
153 if (status != ARES_SUCCESS)
154 break;
155 vptr += len;
156
157 status = ares_expand_name(vptr, abuf, alen, &naptr_curr->replacement, &len);
158 if (status != ARES_SUCCESS)
159 break;
160 }
161
162 /* Don't lose memory in the next iteration */
163 free (rr_name);
164 rr_name = NULL;
165
166 /* Move on to the next record */
167 aptr += rr_len;
168 }
169
170 if (hostname)
171 free (hostname);
172 if (rr_name)
173 free (rr_name);
174
175 /* clean up on error */
176 if (status != ARES_SUCCESS)
177 {
178 if (naptr_head)
179 ares_free_data (naptr_head);
180 return status;
181 }
182
183 /* everything looks fine, return the data */
184 *naptr_out = naptr_head;
185
186 return ARES_SUCCESS;
187 }
188
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