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
14extern const struct _ns_flagdata _ns_flagdata[] attribute_hidden;
15
16extern unsigned int __ns_get16 (const unsigned char *) __THROW;
17extern unsigned long __ns_get32 (const unsigned char *) __THROW;
18int __ns_name_ntop (const unsigned char *, char *, size_t) __THROW;
19int __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
31libresolv_hidden_proto (ns_get16)
32libresolv_hidden_proto (ns_get32)
33libresolv_hidden_proto (ns_put16)
34libresolv_hidden_proto (ns_put32)
35libresolv_hidden_proto (ns_initparse)
36libresolv_hidden_proto (ns_skiprr)
37libresolv_hidden_proto (ns_parserr)
38libresolv_hidden_proto (ns_sprintrr)
39libresolv_hidden_proto (ns_sprintrrf)
40libresolv_hidden_proto (ns_samedomain)
41libresolv_hidden_proto (ns_format_ttl)
42
43extern __typeof (ns_makecanon) __libc_ns_makecanon;
44libc_hidden_proto (__libc_ns_makecanon)
45extern __typeof (ns_name_compress) __ns_name_compress;
46libc_hidden_proto (__ns_name_compress)
47extern __typeof (ns_name_ntop) __ns_name_ntop;
48libc_hidden_proto (__ns_name_ntop)
49extern __typeof (ns_name_pack) __ns_name_pack;
50libc_hidden_proto (__ns_name_pack)
51extern __typeof (ns_name_pton) __ns_name_pton;
52libc_hidden_proto (__ns_name_pton)
53extern __typeof (ns_name_skip) __ns_name_skip;
54libc_hidden_proto (__ns_name_skip)
55extern __typeof (ns_name_uncompress) __ns_name_uncompress;
56libc_hidden_proto (__ns_name_uncompress)
57extern __typeof (ns_name_unpack) __ns_name_unpack;
58libc_hidden_proto (__ns_name_unpack)
59extern __typeof (ns_samename) __libc_ns_samename;
60libc_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. */
68int __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. */
72struct 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. */
84static inline int
85ns_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. */
91static inline int
92ns_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. */
99static inline int
100ns_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. */
107static inline int
108ns_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. */
115static inline const unsigned char *
116ns_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. */
122static inline const int
123ns_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). */
130static inline const int
131ns_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. */
145struct 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