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