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git.ipfire.org Git - people/ms/u-boot.git/blob - net/dns.c
4 * Copyright (c) 2008 Pieter Voorthuijsen <pieter.voorthuijsen@prodrive.nl>
5 * Copyright (c) 2009 Robin Getz <rgetz@blackfin.uclinux.org>
7 * This is a simple DNS implementation for U-Boot. It will use the first IP
8 * in the DNS response as net_server_ip. This can then be used for any other
9 * network related activities.
11 * The packet handling is partly based on TADNS, original copyrights
17 * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
19 * "THE BEER-WARE LICENSE" (Revision 42):
20 * Sergey Lyubka wrote this file. As long as you retain this notice you
21 * can do whatever you want with this stuff. If we meet some day, and you think
22 * this stuff is worth it, you can buy me a beer in return.
28 #include <asm/unaligned.h>
32 char *NetDNSResolve
; /* The host to resolve */
33 char *NetDNSenvvar
; /* The envvar to store the answer in */
35 static int DnsOurPort
;
40 struct header
*header
;
45 enum dns_query_type qtype
= DNS_A_RECORD
;
48 pkt
= p
= (uchar
*)(NetTxPacket
+ NetEthHdrSize() + IP_UDP_HDR_SIZE
);
50 /* Prepare DNS packet header */
51 header
= (struct header
*) pkt
;
53 header
->flags
= htons(0x100); /* standard query */
54 header
->nqueries
= htons(1); /* Just one query */
60 name_len
= strlen(name
);
61 p
= (uchar
*) &header
->data
; /* For encoding host name into packet */
64 s
= strchr(name
, '.');
68 n
= s
- name
; /* Chunk length */
69 *p
++ = n
; /* Copy length */
70 memcpy(p
, name
, n
); /* Copy chunk */
80 *p
++ = 0; /* Mark end of host name */
81 *p
++ = 0; /* Some servers require double null */
82 *p
++ = (unsigned char) qtype
; /* Query Type */
85 *p
++ = 1; /* Class: inet, 0x0001 */
87 n
= p
- pkt
; /* Total packet length */
88 debug("Packet size %d\n", n
);
90 DnsOurPort
= random_port();
92 NetSendUDPPacket(NetServerEther
, net_dns_server
, DNS_SERVICE_PORT
,
94 debug("DNS packet sent\n");
101 net_set_state(NETLOOP_FAIL
);
104 static void dns_handler(uchar
*pkt
, unsigned dest
, struct in_addr sip
,
105 unsigned src
, unsigned len
)
107 struct header
*header
;
108 const unsigned char *p
, *e
, *s
;
110 int found
, stop
, dlen
;
112 struct in_addr ip_addr
;
115 debug("%s\n", __func__
);
116 if (dest
!= DnsOurPort
)
119 for (i
= 0; i
< len
; i
+= 4)
120 debug("0x%p - 0x%.2x 0x%.2x 0x%.2x 0x%.2x\n",
121 pkt
+i
, pkt
[i
], pkt
[i
+1], pkt
[i
+2], pkt
[i
+3]);
123 /* We sent one query. We want to have a single answer: */
124 header
= (struct header
*) pkt
;
125 if (ntohs(header
->nqueries
) != 1)
128 /* Received 0 answers */
129 if (header
->nanswers
== 0) {
130 puts("DNS: host not found\n");
131 net_set_state(NETLOOP_SUCCESS
);
136 s
= &header
->data
[0];
138 for (p
= s
; p
< e
&& *p
!= '\0'; p
++)
141 /* We sent query class 1, query type 1 */
142 if (&p
[5] > e
|| get_unaligned_be16(p
+1) != DNS_A_RECORD
) {
143 puts("DNS: response was not an A record\n");
144 net_set_state(NETLOOP_SUCCESS
);
148 /* Go to the first answer section */
151 /* Loop through the answers, we want A type answer */
152 for (found
= stop
= 0; !stop
&& &p
[12] < e
; ) {
154 /* Skip possible name in CNAME answer */
156 while (*p
&& &p
[12] < e
)
160 debug("Name (Offset in header): %d\n", p
[1]);
162 type
= get_unaligned_be16(p
+2);
163 debug("type = %d\n", type
);
164 if (type
== DNS_CNAME_RECORD
) {
165 /* CNAME answer. shift to the next section */
166 debug("Found canonical name\n");
167 dlen
= get_unaligned_be16(p
+10);
168 debug("dlen = %d\n", dlen
);
170 } else if (type
== DNS_A_RECORD
) {
171 debug("Found A-record\n");
174 debug("Unknown type\n");
179 if (found
&& &p
[12] < e
) {
181 dlen
= get_unaligned_be16(p
+10);
183 memcpy(&ip_addr
, p
, 4);
186 ip_to_string(ip_addr
, IPStr
);
187 printf("%s\n", IPStr
);
189 setenv(NetDNSenvvar
, IPStr
);
191 puts("server responded with invalid IP number\n");
194 net_set_state(NETLOOP_SUCCESS
);
200 debug("%s\n", __func__
);
202 NetSetTimeout(DNS_TIMEOUT
, DnsTimeout
);
203 net_set_udp_handler(dns_handler
);
205 /* Clear a previous MAC address, the server IP might have changed. */
206 memset(NetServerEther
, 0, sizeof(NetServerEther
));