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1a32bf41 RG |
1 | /* |
2 | * DNS support driver | |
3 | * | |
4 | * Copyright (c) 2008 Pieter Voorthuijsen <pieter.voorthuijsen@prodrive.nl> | |
5 | * Copyright (c) 2009 Robin Getz <rgetz@blackfin.uclinux.org> | |
6 | * | |
7 | * This is a simple DNS implementation for U-Boot. It will use the first IP | |
049a95a7 | 8 | * in the DNS response as net_server_ip. This can then be used for any other |
1a32bf41 RG |
9 | * network related activities. |
10 | * | |
11 | * The packet handling is partly based on TADNS, original copyrights | |
12 | * follow below. | |
13 | * | |
14 | */ | |
15 | ||
16 | /* | |
17 | * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com> | |
18 | * | |
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. | |
23 | */ | |
24 | ||
25 | #include <common.h> | |
26 | #include <command.h> | |
27 | #include <net.h> | |
6dc809f4 | 28 | #include <asm/unaligned.h> |
1a32bf41 RG |
29 | |
30 | #include "dns.h" | |
31 | ||
786eac5f JH |
32 | char *net_dns_resolve; /* The host to resolve */ |
33 | char *net_dns_env_var; /* The envvar to store the answer in */ | |
1a32bf41 | 34 | |
786eac5f | 35 | static int dns_our_port; |
1a32bf41 | 36 | |
786eac5f | 37 | static void dns_send(void) |
1a32bf41 RG |
38 | { |
39 | struct header *header; | |
40 | int n, name_len; | |
41 | uchar *p, *pkt; | |
42 | const char *s; | |
43 | const char *name; | |
44 | enum dns_query_type qtype = DNS_A_RECORD; | |
45 | ||
786eac5f | 46 | name = net_dns_resolve; |
1203fcce JH |
47 | pkt = (uchar *)(net_tx_packet + net_eth_hdr_size() + IP_UDP_HDR_SIZE); |
48 | p = pkt; | |
1a32bf41 RG |
49 | |
50 | /* Prepare DNS packet header */ | |
786eac5f | 51 | header = (struct header *)pkt; |
1a32bf41 RG |
52 | header->tid = 1; |
53 | header->flags = htons(0x100); /* standard query */ | |
54 | header->nqueries = htons(1); /* Just one query */ | |
55 | header->nanswers = 0; | |
56 | header->nauth = 0; | |
57 | header->nother = 0; | |
58 | ||
59 | /* Encode DNS name */ | |
60 | name_len = strlen(name); | |
786eac5f | 61 | p = (uchar *)&header->data; /* For encoding host name into packet */ |
1a32bf41 RG |
62 | |
63 | do { | |
64 | s = strchr(name, '.'); | |
65 | if (!s) | |
66 | s = name + name_len; | |
67 | ||
68 | n = s - name; /* Chunk length */ | |
69 | *p++ = n; /* Copy length */ | |
70 | memcpy(p, name, n); /* Copy chunk */ | |
71 | p += n; | |
72 | ||
73 | if (*s == '.') | |
74 | n++; | |
75 | ||
76 | name += n; | |
77 | name_len -= n; | |
78 | } while (*s != '\0'); | |
79 | ||
80 | *p++ = 0; /* Mark end of host name */ | |
81 | *p++ = 0; /* Some servers require double null */ | |
82 | *p++ = (unsigned char) qtype; /* Query Type */ | |
83 | ||
84 | *p++ = 0; | |
85 | *p++ = 1; /* Class: inet, 0x0001 */ | |
86 | ||
87 | n = p - pkt; /* Total packet length */ | |
88 | debug("Packet size %d\n", n); | |
89 | ||
786eac5f | 90 | dns_our_port = random_port(); |
1a32bf41 | 91 | |
1203fcce | 92 | net_send_udp_packet(net_server_ethaddr, net_dns_server, |
786eac5f | 93 | DNS_SERVICE_PORT, dns_our_port, n); |
1a32bf41 RG |
94 | debug("DNS packet sent\n"); |
95 | } | |
96 | ||
786eac5f | 97 | static void dns_timeout_handler(void) |
1a32bf41 RG |
98 | { |
99 | puts("Timeout\n"); | |
22f6e99d | 100 | net_set_state(NETLOOP_FAIL); |
1a32bf41 RG |
101 | } |
102 | ||
049a95a7 JH |
103 | static void dns_handler(uchar *pkt, unsigned dest, struct in_addr sip, |
104 | unsigned src, unsigned len) | |
1a32bf41 RG |
105 | { |
106 | struct header *header; | |
107 | const unsigned char *p, *e, *s; | |
108 | u16 type, i; | |
109 | int found, stop, dlen; | |
786eac5f | 110 | char ip_str[22]; |
049a95a7 | 111 | struct in_addr ip_addr; |
1a32bf41 RG |
112 | |
113 | ||
114 | debug("%s\n", __func__); | |
786eac5f | 115 | if (dest != dns_our_port) |
1a32bf41 RG |
116 | return; |
117 | ||
118 | for (i = 0; i < len; i += 4) | |
119 | debug("0x%p - 0x%.2x 0x%.2x 0x%.2x 0x%.2x\n", | |
786eac5f | 120 | pkt+i, pkt[i], pkt[i+1], pkt[i+2], pkt[i+3]); |
1a32bf41 | 121 | |
6dc809f4 | 122 | /* We sent one query. We want to have a single answer: */ |
786eac5f | 123 | header = (struct header *)pkt; |
1a32bf41 RG |
124 | if (ntohs(header->nqueries) != 1) |
125 | return; | |
126 | ||
127 | /* Received 0 answers */ | |
128 | if (header->nanswers == 0) { | |
6dc809f4 | 129 | puts("DNS: host not found\n"); |
22f6e99d | 130 | net_set_state(NETLOOP_SUCCESS); |
1a32bf41 RG |
131 | return; |
132 | } | |
133 | ||
134 | /* Skip host name */ | |
135 | s = &header->data[0]; | |
136 | e = pkt + len; | |
137 | for (p = s; p < e && *p != '\0'; p++) | |
138 | continue; | |
139 | ||
140 | /* We sent query class 1, query type 1 */ | |
6dc809f4 BK |
141 | if (&p[5] > e || get_unaligned_be16(p+1) != DNS_A_RECORD) { |
142 | puts("DNS: response was not an A record\n"); | |
22f6e99d | 143 | net_set_state(NETLOOP_SUCCESS); |
1a32bf41 RG |
144 | return; |
145 | } | |
146 | ||
147 | /* Go to the first answer section */ | |
148 | p += 5; | |
149 | ||
150 | /* Loop through the answers, we want A type answer */ | |
151 | for (found = stop = 0; !stop && &p[12] < e; ) { | |
1a32bf41 RG |
152 | /* Skip possible name in CNAME answer */ |
153 | if (*p != 0xc0) { | |
154 | while (*p && &p[12] < e) | |
155 | p++; | |
156 | p--; | |
157 | } | |
158 | debug("Name (Offset in header): %d\n", p[1]); | |
159 | ||
6dc809f4 | 160 | type = get_unaligned_be16(p+2); |
1a32bf41 RG |
161 | debug("type = %d\n", type); |
162 | if (type == DNS_CNAME_RECORD) { | |
163 | /* CNAME answer. shift to the next section */ | |
164 | debug("Found canonical name\n"); | |
6dc809f4 | 165 | dlen = get_unaligned_be16(p+10); |
1a32bf41 RG |
166 | debug("dlen = %d\n", dlen); |
167 | p += 12 + dlen; | |
168 | } else if (type == DNS_A_RECORD) { | |
169 | debug("Found A-record\n"); | |
786eac5f JH |
170 | found = 1; |
171 | stop = 1; | |
1a32bf41 RG |
172 | } else { |
173 | debug("Unknown type\n"); | |
174 | stop = 1; | |
175 | } | |
176 | } | |
177 | ||
178 | if (found && &p[12] < e) { | |
6dc809f4 | 179 | dlen = get_unaligned_be16(p+10); |
1a32bf41 | 180 | p += 12; |
049a95a7 | 181 | memcpy(&ip_addr, p, 4); |
1a32bf41 RG |
182 | |
183 | if (p + dlen <= e) { | |
786eac5f JH |
184 | ip_to_string(ip_addr, ip_str); |
185 | printf("%s\n", ip_str); | |
186 | if (net_dns_env_var) | |
187 | setenv(net_dns_env_var, ip_str); | |
188 | } else { | |
1a32bf41 | 189 | puts("server responded with invalid IP number\n"); |
786eac5f | 190 | } |
1a32bf41 RG |
191 | } |
192 | ||
22f6e99d | 193 | net_set_state(NETLOOP_SUCCESS); |
1a32bf41 RG |
194 | } |
195 | ||
786eac5f | 196 | void dns_start(void) |
1a32bf41 RG |
197 | { |
198 | debug("%s\n", __func__); | |
199 | ||
bc0571fc | 200 | net_set_timeout_handler(DNS_TIMEOUT, dns_timeout_handler); |
049a95a7 | 201 | net_set_udp_handler(dns_handler); |
1a32bf41 | 202 | |
f395e75e | 203 | /* Clear a previous MAC address, the server IP might have changed. */ |
0adb5b76 | 204 | memset(net_server_ethaddr, 0, sizeof(net_server_ethaddr)); |
f395e75e | 205 | |
786eac5f | 206 | dns_send(); |
1a32bf41 | 207 | } |