b37f82eb890c682443c14bb7790d1378e93b9300
2 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU Lesser General Public License version 2.1
6 * as published by the Free Software Foundation
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
14 #include <sys/types.h>
21 #include <sys/types.h>
22 #include <sys/socket.h>
23 #include <netinet/in.h>
24 #include <arpa/inet.h>
25 #include <asm/byteorder.h>
26 #include <arpa/nameser.h>
31 #include <libubox/uloop.h>
32 #include <libubox/usock.h>
33 #include <libubox/utils.h>
38 #include "interface.h"
40 char rdata_buffer
[MAX_DATA_LEN
+ 1];
41 static char name_buffer
[MAX_NAME_LEN
+ 1];
44 dns_type_string(uint16_t type
)
70 dns_send_question(struct interface
*iface
, const char *question
, int type
)
72 static struct dns_header h
= {
73 .questions
= cpu_to_be16(1),
75 static struct dns_question q
= {
76 .class = cpu_to_be16(1),
78 static struct iovec iov
[] = {
84 .iov_base
= name_buffer
,
93 q
.type
= __cpu_to_be16(type
);
95 len
= dn_comp(question
, (void *) name_buffer
, sizeof(name_buffer
), NULL
, NULL
);
101 if (interface_send_packet(iface
, iov
, ARRAY_SIZE(iov
)) < 0)
102 fprintf(stderr
, "failed to send question\n");
104 DBG(1, "Q <- %s %s\n", dns_type_string(type
), question
);
117 static struct dns_reply dns_reply
[1 + (MAX_ANSWER
* 3)];
118 static int dns_answer_cnt
;
121 dns_init_answer(void)
127 dns_add_answer(int type
, const uint8_t *rdata
, uint16_t rdlength
)
129 struct dns_reply
*a
= &dns_reply
[dns_answer_cnt
];
130 if (dns_answer_cnt
== MAX_ANSWER
)
132 a
->rdata
= memdup(rdata
, rdlength
);
134 a
->rdlength
= rdlength
;
139 dns_send_answer(struct interface
*iface
, const char *answer
)
142 struct dns_header h
= { 0 };
149 h
.answers
= __cpu_to_be16(dns_answer_cnt
);
150 h
.flags
= __cpu_to_be16(0x8400);
152 iov
= alloca(sizeof(struct iovec
) * ((dns_answer_cnt
* 3) + 1));
153 iov
[0].iov_base
= &h
;
154 iov
[0].iov_len
= sizeof(struct dns_header
);
156 for (i
= 0; i
< dns_answer_cnt
; i
++) {
157 struct dns_answer
*a
= &dns_reply
[i
].a
;
158 int id
= (i
* 3) + 1;
160 memset(a
, 0, sizeof(*a
));
161 a
->type
= __cpu_to_be16(dns_reply
[i
].type
);
162 a
->class = __cpu_to_be16(1);
163 a
->ttl
= __cpu_to_be32(announce_ttl
);
164 a
->rdlength
= __cpu_to_be16(dns_reply
[i
].rdlength
);
166 len
= dn_comp(answer
, buffer
, sizeof(buffer
), NULL
, NULL
);
170 dns_reply
[i
].buffer
= iov
[id
].iov_base
= memdup(buffer
, len
);
171 iov
[id
].iov_len
= len
;
173 iov
[id
+ 1].iov_base
= a
;
174 iov
[id
+ 1].iov_len
= sizeof(struct dns_answer
);
176 iov
[id
+ 2].iov_base
= dns_reply
[i
].rdata
;
177 iov
[id
+ 2].iov_len
= dns_reply
[i
].rdlength
;
179 DBG(1, "A <- %s %s\n", dns_type_string(dns_reply
[i
].type
), answer
);
182 if (interface_send_packet(iface
, iov
, (dns_answer_cnt
* 3) + 1) < 0)
183 fprintf(stderr
, "failed to send question\n");
185 for (i
= 0; i
< dns_answer_cnt
; i
++) {
186 free(dns_reply
[i
].buffer
);
187 free(dns_reply
[i
].rdata
);
193 scan_name(const uint8_t *buffer
, int len
)
197 while (len
&& (*buffer
!= '\0')) {
200 if (IS_COMPRESSED(l
))
208 if (!len
|| !offset
|| (*buffer
!= '\0'))
215 dns_consume_header(uint8_t **data
, int *len
)
217 struct dns_header
*h
= (struct dns_header
*) *data
;
218 uint16_t *swap
= (uint16_t *) h
;
221 if (*len
< sizeof(struct dns_header
))
224 while (endianess
--) {
225 *swap
= __be16_to_cpu(*swap
);
229 *len
-= sizeof(struct dns_header
);
230 *data
+= sizeof(struct dns_header
);
236 dns_consume_question(uint8_t **data
, int *len
)
238 struct dns_question
*q
= (struct dns_question
*) *data
;
239 uint16_t *swap
= (uint16_t *) q
;
242 if (*len
< sizeof(struct dns_question
))
245 while (endianess
--) {
246 *swap
= __be16_to_cpu(*swap
);
250 *len
-= sizeof(struct dns_question
);
251 *data
+= sizeof(struct dns_question
);
257 dns_consume_answer(uint8_t **data
, int *len
)
259 struct dns_answer
*a
= (struct dns_answer
*) *data
;
261 if (*len
< sizeof(struct dns_answer
))
264 a
->type
= __be16_to_cpu(a
->type
);
265 a
->class = __be16_to_cpu(a
->class);
266 a
->ttl
= __be32_to_cpu(a
->ttl
);
267 a
->rdlength
= __be16_to_cpu(a
->rdlength
);
269 *len
-= sizeof(struct dns_answer
);
270 *data
+= sizeof(struct dns_answer
);
276 dns_consume_name(const uint8_t *base
, int blen
, uint8_t **data
, int *len
)
278 int nlen
= scan_name(*data
, *len
);
283 if (dn_expand(base
, base
+ blen
, *data
, name_buffer
, MAX_NAME_LEN
) < 0) {
284 perror("dns_consume_name/dn_expand");