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1 | .\" $OpenBSD: getrrsetbyname.3,v 1.11 2003/05/30 21:37:59 jmc Exp $ | ||
2 | .\" | ||
3 | .\" Copyright (C) 2000, 2001 Internet Software Consortium. | ||
4 | .\" | ||
5 | .\" Permission to use, copy, modify, and distribute this software for any | ||
6 | .\" purpose with or without fee is hereby granted, provided that the above | ||
7 | .\" copyright notice and this permission notice appear in all copies. | ||
8 | .\" | ||
9 | .\" THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM | ||
10 | .\" DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL | ||
11 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL | ||
12 | .\" INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, | ||
13 | .\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING | ||
14 | .\" FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, | ||
15 | .\" NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION | ||
16 | .\" WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | ||
17 | .\" | ||
18 | .Dd October 18, 2000 | ||
19 | .Dt GETRRSETBYNAME 3 | ||
20 | .Os | ||
21 | .Sh NAME | ||
22 | .Nm getrrsetbyname | ||
23 | .Nd retrieve DNS records | ||
24 | .Sh SYNOPSIS | ||
25 | .Fd #include <netdb.h> | ||
26 | .Ft int | ||
27 | .Fn getrrsetbyname "const char *hostname" "unsigned int rdclass" \ | ||
28 | "unsigned int rdtype" "unsigned int flags" "struct rrsetinfo **res" | ||
29 | .Ft int | ||
30 | .Fn freerrset "struct rrsetinfo **rrset" | ||
31 | .Sh DESCRIPTION | ||
32 | .Fn getrrsetbyname | ||
33 | gets a set of resource records associated with a | ||
34 | .Fa hostname , | ||
35 | .Fa class | ||
36 | and | ||
37 | .Fa type . | ||
38 | .Fa hostname | ||
39 | is a pointer a to null-terminated string. | ||
40 | The | ||
41 | .Fa flags | ||
42 | field is currently unused and must be zero. | ||
43 | .Pp | ||
44 | After a successful call to | ||
45 | .Fn getrrsetbyname , | ||
46 | .Fa *res | ||
47 | is a pointer to an | ||
48 | .Li rrsetinfo | ||
49 | structure, containing a list of one or more | ||
50 | .Li rdatainfo | ||
51 | structures containing resource records and potentially another list of | ||
52 | .Li rdatainfo | ||
53 | structures containing SIG resource records associated with those records. | ||
54 | The members | ||
55 | .Li rri_rdclass | ||
56 | and | ||
57 | .Li rri_rdtype | ||
58 | are copied from the parameters. | ||
59 | .Li rri_ttl | ||
60 | and | ||
61 | .Li rri_name | ||
62 | are properties of the obtained rrset. | ||
63 | The resource records contained in | ||
64 | .Li rri_rdatas | ||
65 | and | ||
66 | .Li rri_sigs | ||
67 | are in uncompressed DNS wire format. | ||
68 | Properties of the rdataset are represented in the | ||
69 | .Li rri_flags | ||
70 | bitfield. | ||
71 | If the | ||
72 | .Dv RRSET_VALIDATED | ||
73 | bit is set, the data has been DNSSEC | ||
74 | validated and the signatures verified. | ||
75 | .Pp | ||
76 | The following structures are used: | ||
77 | .Bd -literal -offset | ||
78 | struct rdatainfo { | ||
79 | unsigned int rdi_length; /* length of data */ | ||
80 | unsigned char *rdi_data; /* record data */ | ||
81 | }; | ||
82 | |||
83 | struct rrsetinfo { | ||
84 | unsigned int rri_flags; /* RRSET_VALIDATED ... */ | ||
85 | unsigned int rri_rdclass; /* class number */ | ||
86 | unsigned int rri_rdtype; /* RR type number */ | ||
87 | unsigned int rri_ttl; /* time to live */ | ||
88 | unsigned int rri_nrdatas; /* size of rdatas array */ | ||
89 | unsigned int rri_nsigs; /* size of sigs array */ | ||
90 | char *rri_name; /* canonical name */ | ||
91 | struct rdatainfo *rri_rdatas; /* individual records */ | ||
92 | struct rdatainfo *rri_sigs; /* individual signatures */ | ||
93 | }; | ||
94 | .Ed | ||
95 | .Pp | ||
96 | All of the information returned by | ||
97 | .Fn getrrsetbyname | ||
98 | is dynamically allocated: the | ||
99 | .Li rrsetinfo | ||
100 | and | ||
101 | .Li rdatainfo | ||
102 | structures, | ||
103 | and the canonical host name strings pointed to by the | ||
104 | .Li rrsetinfo | ||
105 | structure. | ||
106 | Memory allocated for the dynamically allocated structures created by | ||
107 | a successful call to | ||
108 | .Fn getrrsetbyname | ||
109 | is released by | ||
110 | .Fn freerrset . | ||
111 | .Li rrset | ||
112 | is a pointer to a | ||
113 | .Li struct rrset | ||
114 | created by a call to | ||
115 | .Fn getrrsetbyname . | ||
116 | .Pp | ||
117 | If the EDNS0 option is activated in | ||
118 | .Xr resolv.conf 5 , | ||
119 | .Fn getrrsetbyname | ||
120 | will request DNSSEC authentication using the EDNS0 DNSSEC OK (DO) bit. | ||
121 | .Sh RETURN VALUES | ||
122 | .Fn getrrsetbyname | ||
123 | returns zero on success, and one of the following error | ||
124 | codes if an error occurred: | ||
125 | .Pp | ||
126 | .Bl -tag -width ERRSET_NOMEMORY -compact | ||
127 | .It Dv ERRSET_NONAME | ||
128 | the name does not exist | ||
129 | .It Dv ERRSET_NODATA | ||
130 | the name exists, but does not have data of the desired type | ||
131 | .It Dv ERRSET_NOMEMORY | ||
132 | memory could not be allocated | ||
133 | .It Dv ERRSET_INVAL | ||
134 | a parameter is invalid | ||
135 | .It Dv ERRSET_FAIL | ||
136 | other failure | ||
137 | .El | ||
138 | .Sh SEE ALSO | ||
139 | .Xr resolver 3 , | ||
140 | .Xr resolv.conf 5 , | ||
141 | .Xr named 8 | ||
142 | .Sh HISTORY | ||
143 | .Fn getrrsetbyname | ||
144 | first appeared in | ||
145 | .Ox 3.0 . | ||
146 | The API first appeared in ISC BIND version 9. | ||
147 | .Sh AUTHORS | ||
148 | .An Jakob Schlyter Aq jakob@openbsd.org | ||
149 | .Sh CAVEATS | ||
150 | The | ||
151 | .Dv RRSET_VALIDATED | ||
152 | flag in | ||
153 | .Li rri_flags | ||
154 | is set if the AD (authenticated data) bit in the DNS answer is | ||
155 | set. | ||
156 | This flag | ||
157 | .Em should not | ||
158 | be trusted unless the transport between the nameserver and the resolver | ||
159 | is secure (e.g. IPsec, trusted network, loopback communication). | ||
160 | .Sh BUGS | ||
161 | The data in | ||
162 | .Li *rdi_data | ||
163 | should be returned in uncompressed wire format. | ||
164 | Currently, the data is in compressed format and the caller can't | ||
165 | uncompress since it doesn't have the full message. | ||