1 | /* |
2 | * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") |
3 | * Copyright (c) 1996,1999 by Internet Software Consortium. |
4 | * |
5 | * Permission to use, copy, modify, and distribute this software for any |
6 | * purpose with or without fee is hereby granted, provided that the above |
7 | * copyright notice and this permission notice appear in all copies. |
8 | * |
9 | * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES |
10 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
11 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR |
12 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
13 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
14 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
15 | * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
16 | */ |
17 | |
18 | #if !defined(_LIBC) && !defined(lint) |
19 | static const char rcsid[] = "$BINDId: ns_parse.c,v 8.13 1999/10/13 16:39:35 vixie Exp $" ; |
20 | #endif |
21 | |
22 | /* Import. */ |
23 | |
24 | #include <sys/types.h> |
25 | |
26 | #include <netinet/in.h> |
27 | #include <arpa/nameser.h> |
28 | |
29 | #include <errno.h> |
30 | #include <resolv.h> |
31 | #include <string.h> |
32 | |
33 | /* Forward. */ |
34 | |
35 | static void setsection(ns_msg *msg, ns_sect sect); |
36 | |
37 | /* Macros. */ |
38 | |
39 | #define RETERR(err) do { __set_errno (err); return (-1); } while (0) |
40 | |
41 | /* Public. */ |
42 | |
43 | /* These need to be in the same order as the nres.h:ns_flag enum. */ |
44 | const struct _ns_flagdata _ns_flagdata[16] = { |
45 | { 0x8000, 15 }, /*%< qr. */ |
46 | { 0x7800, 11 }, /*%< opcode. */ |
47 | { 0x0400, 10 }, /*%< aa. */ |
48 | { 0x0200, 9 }, /*%< tc. */ |
49 | { 0x0100, 8 }, /*%< rd. */ |
50 | { 0x0080, 7 }, /*%< ra. */ |
51 | { 0x0040, 6 }, /*%< z. */ |
52 | { 0x0020, 5 }, /*%< ad. */ |
53 | { 0x0010, 4 }, /*%< cd. */ |
54 | { 0x000f, 0 }, /*%< rcode. */ |
55 | { 0x0000, 0 }, /*%< expansion (1/6). */ |
56 | { 0x0000, 0 }, /*%< expansion (2/6). */ |
57 | { 0x0000, 0 }, /*%< expansion (3/6). */ |
58 | { 0x0000, 0 }, /*%< expansion (4/6). */ |
59 | { 0x0000, 0 }, /*%< expansion (5/6). */ |
60 | { 0x0000, 0 }, /*%< expansion (6/6). */ |
61 | }; |
62 | |
63 | #undef ns_msg_getflag |
64 | int ns_msg_getflag(ns_msg handle, int flag) { |
65 | return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); |
66 | } |
67 | |
68 | int |
69 | ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { |
70 | const u_char *optr = ptr; |
71 | |
72 | for ((void)NULL; count > 0; count--) { |
73 | int b, rdlength; |
74 | |
75 | b = dn_skipname(ptr, eom); |
76 | if (b < 0) |
77 | RETERR(EMSGSIZE); |
78 | ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; |
79 | if (section != ns_s_qd) { |
80 | if (ptr + NS_INT32SZ + NS_INT16SZ > eom) |
81 | RETERR(EMSGSIZE); |
82 | ptr += NS_INT32SZ/*TTL*/; |
83 | NS_GET16(rdlength, ptr); |
84 | ptr += rdlength/*RData*/; |
85 | } |
86 | } |
87 | if (ptr > eom) |
88 | RETERR(EMSGSIZE); |
89 | return (ptr - optr); |
90 | } |
91 | libresolv_hidden_def (ns_skiprr) |
92 | |
93 | int |
94 | ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { |
95 | const u_char *eom = msg + msglen; |
96 | int i; |
97 | |
98 | memset(handle, 0x5e, sizeof *handle); |
99 | handle->_msg = msg; |
100 | handle->_eom = eom; |
101 | if (msg + NS_INT16SZ > eom) |
102 | RETERR(EMSGSIZE); |
103 | NS_GET16(handle->_id, msg); |
104 | if (msg + NS_INT16SZ > eom) |
105 | RETERR(EMSGSIZE); |
106 | NS_GET16(handle->_flags, msg); |
107 | for (i = 0; i < ns_s_max; i++) { |
108 | if (msg + NS_INT16SZ > eom) |
109 | RETERR(EMSGSIZE); |
110 | NS_GET16(handle->_counts[i], msg); |
111 | } |
112 | for (i = 0; i < ns_s_max; i++) |
113 | if (handle->_counts[i] == 0) |
114 | handle->_sections[i] = NULL; |
115 | else { |
116 | int b = ns_skiprr(msg, eom, (ns_sect)i, |
117 | handle->_counts[i]); |
118 | |
119 | if (b < 0) |
120 | return (-1); |
121 | handle->_sections[i] = msg; |
122 | msg += b; |
123 | } |
124 | if (msg != eom) |
125 | RETERR(EMSGSIZE); |
126 | setsection(handle, ns_s_max); |
127 | return (0); |
128 | } |
129 | libresolv_hidden_def (ns_initparse) |
130 | |
131 | int |
132 | ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { |
133 | int b; |
134 | int tmp; |
135 | |
136 | /* Make section right. */ |
137 | tmp = section; |
138 | if (tmp < 0 || section >= ns_s_max) |
139 | RETERR(ENODEV); |
140 | if (section != handle->_sect) |
141 | setsection(handle, section); |
142 | |
143 | /* Make rrnum right. */ |
144 | if (rrnum == -1) |
145 | rrnum = handle->_rrnum; |
146 | if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) |
147 | RETERR(ENODEV); |
148 | if (rrnum < handle->_rrnum) |
149 | setsection(handle, section); |
150 | if (rrnum > handle->_rrnum) { |
151 | b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, |
152 | rrnum - handle->_rrnum); |
153 | |
154 | if (b < 0) |
155 | return (-1); |
156 | handle->_msg_ptr += b; |
157 | handle->_rrnum = rrnum; |
158 | } |
159 | |
160 | /* Do the parse. */ |
161 | b = dn_expand(handle->_msg, handle->_eom, |
162 | handle->_msg_ptr, rr->name, NS_MAXDNAME); |
163 | if (b < 0) |
164 | return (-1); |
165 | handle->_msg_ptr += b; |
166 | if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) |
167 | RETERR(EMSGSIZE); |
168 | NS_GET16(rr->type, handle->_msg_ptr); |
169 | NS_GET16(rr->rr_class, handle->_msg_ptr); |
170 | if (section == ns_s_qd) { |
171 | rr->ttl = 0; |
172 | rr->rdlength = 0; |
173 | rr->rdata = NULL; |
174 | } else { |
175 | if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) |
176 | RETERR(EMSGSIZE); |
177 | NS_GET32(rr->ttl, handle->_msg_ptr); |
178 | NS_GET16(rr->rdlength, handle->_msg_ptr); |
179 | if (handle->_msg_ptr + rr->rdlength > handle->_eom) |
180 | RETERR(EMSGSIZE); |
181 | rr->rdata = handle->_msg_ptr; |
182 | handle->_msg_ptr += rr->rdlength; |
183 | } |
184 | if (++handle->_rrnum > handle->_counts[(int)section]) |
185 | setsection(handle, (ns_sect)((int)section + 1)); |
186 | |
187 | /* All done. */ |
188 | return (0); |
189 | } |
190 | libresolv_hidden_def (ns_parserr) |
191 | |
192 | /* Private. */ |
193 | |
194 | static void |
195 | setsection(ns_msg *msg, ns_sect sect) { |
196 | msg->_sect = sect; |
197 | if (sect == ns_s_max) { |
198 | msg->_rrnum = -1; |
199 | msg->_msg_ptr = NULL; |
200 | } else { |
201 | msg->_rrnum = 0; |
202 | msg->_msg_ptr = msg->_sections[(int)sect]; |
203 | } |
204 | } |
205 | |
206 | /*! \file */ |
207 | |