1 | #ifndef _ARPA_NAMESER_H_ |
2 | |
3 | #include <resolv/arpa/nameser.h> |
4 | |
5 | # ifndef _ISOMAC |
6 | |
7 | /* If the machine allows unaligned access we can do better than using |
8 | the NS_GET16, NS_GET32, NS_PUT16, and NS_PUT32 macros from the |
9 | installed header. */ |
10 | #include <string.h> |
11 | #include <stdint.h> |
12 | #include <netinet/in.h> |
13 | |
14 | extern const struct _ns_flagdata _ns_flagdata[] attribute_hidden; |
15 | |
16 | #if _STRING_ARCH_unaligned |
17 | |
18 | # undef NS_GET16 |
19 | # define NS_GET16(s, cp) \ |
20 | do { \ |
21 | const uint16_t *t_cp = (const uint16_t *) (cp); \ |
22 | (s) = ntohs (*t_cp); \ |
23 | (cp) += NS_INT16SZ; \ |
24 | } while (0) |
25 | |
26 | # undef NS_GET32 |
27 | # define NS_GET32(l, cp) \ |
28 | do { \ |
29 | const uint32_t *t_cp = (const uint32_t *) (cp); \ |
30 | (l) = ntohl (*t_cp); \ |
31 | (cp) += NS_INT32SZ; \ |
32 | } while (0) |
33 | |
34 | # undef NS_PUT16 |
35 | # define NS_PUT16(s, cp) \ |
36 | do { \ |
37 | uint16_t *t_cp = (uint16_t *) (cp); \ |
38 | *t_cp = htons (s); \ |
39 | (cp) += NS_INT16SZ; \ |
40 | } while (0) |
41 | |
42 | # undef NS_PUT32 |
43 | # define NS_PUT32(l, cp) \ |
44 | do { \ |
45 | uint32_t *t_cp = (uint32_t *) (cp); \ |
46 | *t_cp = htonl (l); \ |
47 | (cp) += NS_INT32SZ; \ |
48 | } while (0) |
49 | |
50 | #endif |
51 | |
52 | extern unsigned int __ns_get16 (const unsigned char *) __THROW; |
53 | extern unsigned long __ns_get32 (const unsigned char *) __THROW; |
54 | int __ns_name_ntop (const unsigned char *, char *, size_t) __THROW; |
55 | int __ns_name_unpack (const unsigned char *, const unsigned char *, |
56 | const unsigned char *, unsigned char *, size_t) __THROW; |
57 | |
58 | /* Like ns_samename, but for uncompressed binary names. Return true |
59 | if the two arguments compare are equal as case-insensitive domain |
60 | names. */ |
61 | _Bool __ns_samebinaryname (const unsigned char *, const unsigned char *) |
62 | attribute_hidden; |
63 | |
64 | #define ns_msg_getflag(handle, flag) \ |
65 | (((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift) |
66 | |
67 | libresolv_hidden_proto (ns_get16) |
68 | libresolv_hidden_proto (ns_get32) |
69 | libresolv_hidden_proto (ns_put16) |
70 | libresolv_hidden_proto (ns_put32) |
71 | libresolv_hidden_proto (ns_initparse) |
72 | libresolv_hidden_proto (ns_skiprr) |
73 | libresolv_hidden_proto (ns_parserr) |
74 | libresolv_hidden_proto (ns_sprintrr) |
75 | libresolv_hidden_proto (ns_sprintrrf) |
76 | libresolv_hidden_proto (ns_samedomain) |
77 | libresolv_hidden_proto (ns_format_ttl) |
78 | |
79 | extern __typeof (ns_makecanon) __libc_ns_makecanon; |
80 | libc_hidden_proto (__libc_ns_makecanon) |
81 | extern __typeof (ns_name_compress) __ns_name_compress; |
82 | libc_hidden_proto (__ns_name_compress) |
83 | extern __typeof (ns_name_ntop) __ns_name_ntop; |
84 | libc_hidden_proto (__ns_name_ntop) |
85 | extern __typeof (ns_name_pack) __ns_name_pack; |
86 | libc_hidden_proto (__ns_name_pack) |
87 | extern __typeof (ns_name_pton) __ns_name_pton; |
88 | libc_hidden_proto (__ns_name_pton) |
89 | extern __typeof (ns_name_skip) __ns_name_skip; |
90 | libc_hidden_proto (__ns_name_skip) |
91 | extern __typeof (ns_name_uncompress) __ns_name_uncompress; |
92 | libc_hidden_proto (__ns_name_uncompress) |
93 | extern __typeof (ns_name_unpack) __ns_name_unpack; |
94 | libc_hidden_proto (__ns_name_unpack) |
95 | extern __typeof (ns_samename) __libc_ns_samename; |
96 | libc_hidden_proto (__libc_ns_samename) |
97 | |
98 | /* Packet parser helper functions. */ |
99 | |
100 | /* Verify that P points to an uncompressed domain name in wire format. |
101 | On success, return the length of the encoded name, including the |
102 | terminating null byte. On failure, return -1 and set errno. EOM |
103 | must point one past the last byte in the packet. */ |
104 | int __ns_name_length_uncompressed (const unsigned char *p, |
105 | const unsigned char *eom) attribute_hidden; |
106 | |
107 | /* Iterator over the resource records in a DNS packet. */ |
108 | struct ns_rr_cursor |
109 | { |
110 | /* These members are not changed after initialization. */ |
111 | const unsigned char *begin; /* First byte of packet. */ |
112 | const unsigned char *end; /* One past the last byte of the packet. */ |
113 | const unsigned char *first_rr; /* First resource record (or packet end). */ |
114 | |
115 | /* Advanced towards the end while reading the packet. */ |
116 | const unsigned char *current; |
117 | }; |
118 | |
119 | /* Returns the RCODE field from the DNS header. */ |
120 | static inline int |
121 | ns_rr_cursor_rcode (const struct ns_rr_cursor *c) |
122 | { |
123 | return c->begin[3] & 0x0f; /* Lower 4 bits at offset 3. */ |
124 | } |
125 | |
126 | /* Returns the length of the answer section according to the DNS header. */ |
127 | static inline int |
128 | ns_rr_cursor_ancount (const struct ns_rr_cursor *c) |
129 | { |
130 | return c->begin[6] * 256 + c->begin[7]; /* 16 bits at offset 6. */ |
131 | } |
132 | |
133 | /* Returns the length of the authority (name server) section according |
134 | to the DNS header. */ |
135 | static inline int |
136 | ns_rr_cursor_nscount (const struct ns_rr_cursor *c) |
137 | { |
138 | return c->begin[8] * 256 + c->begin[9]; /* 16 bits at offset 8. */ |
139 | } |
140 | |
141 | /* Returns the length of the additional data section according to the |
142 | DNS header. */ |
143 | static inline int |
144 | ns_rr_cursor_adcount (const struct ns_rr_cursor *c) |
145 | { |
146 | return c->begin[10] * 256 + c->begin[11]; /* 16 bits at offset 10. */ |
147 | } |
148 | |
149 | /* Returns a pointer to the uncompressed question name in wire |
150 | format. */ |
151 | static inline const unsigned char * |
152 | ns_rr_cursor_qname (const struct ns_rr_cursor *c) |
153 | { |
154 | return c->begin + 12; /* QNAME starts right after the header. */ |
155 | } |
156 | |
157 | /* Returns the question type of the first and only question. */ |
158 | static inline const int |
159 | ns_rr_cursor_qtype (const struct ns_rr_cursor *c) |
160 | { |
161 | /* 16 bits 4 bytes back from the first RR header start. */ |
162 | return c->first_rr[-4] * 256 + c->first_rr[-3]; |
163 | } |
164 | |
165 | /* Returns the clss of the first and only question (usally C_IN). */ |
166 | static inline const int |
167 | ns_rr_cursor_qclass (const struct ns_rr_cursor *c) |
168 | { |
169 | /* 16 bits 2 bytes back from the first RR header start. */ |
170 | return c->first_rr[-2] * 256 + c->first_rr[-1]; |
171 | } |
172 | |
173 | /* Initializes *C to cover the packet [BUF, BUF+LEN). Returns false |
174 | if LEN is less than sizeof (*HD), if the packet does not contain a |
175 | full (uncompressed) question, or if the question count is not 1. */ |
176 | _Bool __ns_rr_cursor_init (struct ns_rr_cursor *c, |
177 | const unsigned char *buf, size_t len) |
178 | attribute_hidden; |
179 | |
180 | /* Like ns_rr, but the record owner name is not decoded into text format. */ |
181 | struct ns_rr_wire |
182 | { |
183 | unsigned char rname[NS_MAXCDNAME]; /* Owner name of the record. */ |
184 | uint16_t rtype; /* Resource record type (T_*). */ |
185 | uint16_t rclass; /* Resource record class (C_*). */ |
186 | uint32_t ttl; /* Time-to-live field. */ |
187 | const unsigned char *rdata; /* Start of resource record data. */ |
188 | uint16_t rdlength; /* Length of the data at rdata, in bytes. */ |
189 | }; |
190 | |
191 | /* Attempts to parse the record at C into *RR. On success, return |
192 | true, and C is advanced past the record, and RR->rdata points to |
193 | the record data. On failure, errno is set to EMSGSIZE, and false |
194 | is returned. */ |
195 | _Bool __ns_rr_cursor_next (struct ns_rr_cursor *c, struct ns_rr_wire *rr) |
196 | attribute_hidden; |
197 | |
198 | # endif /* !_ISOMAC */ |
199 | #endif |
200 | |