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 #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