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