include/arpa/nameser.h

   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