1LWRES_PACKET(3) BIND9 LWRES_PACKET(3)
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6 lwres_lwpacket_renderheader, lwres_lwpacket_parseheader - lightweight
7 resolver packet handling functions
8
10 #include <lwres/lwpacket.h>
11 lwres_result_t lwres_lwpacket_renderheader(lwres_buffer_t *b,
13 lwres_lwpacket_t *pkt);
14 lwres_result_t lwres_lwpacket_parseheader(lwres_buffer_t *b,
16 lwres_lwpacket_t *pkt);
17
19 These functions rely on a struct lwres_lwpacket which is defined in
20 lwres/lwpacket.h.
21 typedef struct lwres_lwpacket lwres_lwpacket_t;
23 struct lwres_lwpacket {
25 uint32_t length;
26 uint16_t version;
27 uint16_t pktflags;
28 uint32_t serial;
29 uint32_t opcode;
30 uint32_t result;
31 uint32_t recvlength;
32 uint16_t authtype;
33 uint16_t authlength;
34 };
35 The elements of this structure are:
37 length
39 the overall packet length, including the entire packet header. This
40 field is filled in by the lwres_gabn_*() and lwres_gnba_*() calls.
41 version
43 the header format. There is currently only one format,
44 LWRES_LWPACKETVERSION_0. This field is filled in by the
45 lwres_gabn_*() and lwres_gnba_*() calls.
46 pktflags
48 library-defined flags for this packet: for instance whether the
49 packet is a request or a reply. Flag values can be set, but not
50 defined by the caller. This field is filled in by the application
51 wit the exception of the LWRES_LWPACKETFLAG_RESPONSE bit, which is
52 set by the library in the lwres_gabn_*() and lwres_gnba_*() calls.
53 serial
55 is set by the requestor and is returned in all replies. If two or
56 more packets from the same source have the same serial number and
57 are from the same source, they are assumed to be duplicates and the
58 latter ones may be dropped. This field must be set by the
59 application.
60 opcode
62 indicates the operation. Opcodes between 0x00000000 and 0x03ffffff
63 are reserved for use by the lightweight resolver library. Opcodes
64 between 0x04000000 and 0xffffffff are application defined. This
65 field is filled in by the lwres_gabn_*() and lwres_gnba_*() calls.
66 result
68 is only valid for replies. Results between 0x04000000 and
69 0xffffffff are application defined. Results between 0x00000000 and
70 0x03ffffff are reserved for library use. This field is filled in by
71 the lwres_gabn_*() and lwres_gnba_*() calls.
72 recvlength
74 is the maximum buffer size that the receiver can handle on requests
75 and the size of the buffer needed to satisfy a request when the
76 buffer is too large for replies. This field is supplied by the
77 application.
78 authtype
80 defines the packet level authentication that is used. Authorisation
81 types between 0x1000 and 0xffff are application defined and types
82 between 0x0000 and 0x0fff are reserved for library use. Currently
83 these are not used and must be zero.
84 authlen
86 gives the length of the authentication data. Since packet
87 authentication is currently not used, this must be zero.
88 The following opcodes are currently defined:
90 NOOP
92 Success is always returned and the packet contents are echoed. The
93 lwres_noop_*() functions should be used for this type.
94 GETADDRSBYNAME
96 returns all known addresses for a given name. The lwres_gabn_*()
97 functions should be used for this type.
98 GETNAMEBYADDR
100 return the hostname for the given address. The lwres_gnba_*()
101 functions should be used for this type.
102 lwres_lwpacket_renderheader() transfers the contents of lightweight
104 resolver packet structure lwres_lwpacket_t*pkt in network byte order to
105 the lightweight resolver buffer, *b.
106 lwres_lwpacket_parseheader() performs the converse operation. It
108 transfers data in network byte order from buffer *b to resolver packet
109 *pkt. The contents of the buffer b should correspond to a
110 lwres_lwpacket_t.
111
113 Successful calls to lwres_lwpacket_renderheader() and
114 lwres_lwpacket_parseheader() return LWRES_R_SUCCESS. If there is
115 insufficient space to copy data between the buffer *b and lightweight
116 resolver packet *pkt both functions return LWRES_R_UNEXPECTEDEND.
117
119 Internet Systems Consortium, Inc.
120
122 Copyright © 2000, 2001, 2004, 2005, 2007, 2014-2016, 2018, 2019
123 Internet Systems Consortium, Inc. ("ISC")
124ISC 2007-06-18 LWRES_PACKET(3)