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22 .\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
23 .\" Date: Jun 30, 2000
27 .TH "LWRES_NOOP" "3" "Jun 30, 2000" "BIND9" "BIND9"
28 .\" disable hyphenation
30 .\" disable justification (adjust text to left margin only)
33 lwres_nooprequest_render, lwres_noopresponse_render, lwres_nooprequest_parse, lwres_noopresponse_parse, lwres_noopresponse_free, lwres_nooprequest_free \- lightweight resolver no\-op message handling
36 #include <lwres/lwres.h>
39 .BI "lwres_result_t lwres_nooprequest_render(lwres_context_t\ *" "ctx" ", lwres_nooprequest_t\ *" "req" ", lwres_lwpacket_t\ *" "pkt" ", lwres_buffer_t\ *" "b" ");"
41 .BI "lwres_result_t lwres_noopresponse_render(lwres_context_t\ *" "ctx" ", lwres_noopresponse_t\ *" "req" ", lwres_lwpacket_t\ *" "pkt" ", lwres_buffer_t\ *" "b" ");"
43 .BI "lwres_result_t lwres_nooprequest_parse(lwres_context_t\ *" "ctx" ", lwres_buffer_t\ *" "b" ", lwres_lwpacket_t\ *" "pkt" ", lwres_nooprequest_t\ **" "structp" ");"
45 .BI "lwres_result_t lwres_noopresponse_parse(lwres_context_t\ *" "ctx" ", lwres_buffer_t\ *" "b" ", lwres_lwpacket_t\ *" "pkt" ", lwres_noopresponse_t\ **" "structp" ");"
47 .BI "void lwres_noopresponse_free(lwres_context_t\ *" "ctx" ", lwres_noopresponse_t\ **" "structp" ");"
49 .BI "void lwres_nooprequest_free(lwres_context_t\ *" "ctx" ", lwres_nooprequest_t\ **" "structp" ");"
52 These are low\-level routines for creating and parsing lightweight resolver no\-op request and response messages.
54 The no\-op message is analogous to a
56 packet: a packet is sent to the resolver daemon and is simply echoed back. The opcode is intended to allow a client to determine if the server is operational or not.
58 There are four main functions for the no\-op opcode. One render function converts a no\-op request structure \(em
59 \fBlwres_nooprequest_t\fR
60 \(em to the lighweight resolver's canonical format. It is complemented by a parse function that converts a packet in this canonical format to a no\-op request structure. Another render function converts the no\-op response structure \(em
61 \fBlwres_noopresponse_t\fR
62 to the canonical format. This is complemented by a parse function which converts a packet in canonical format to a no\-op response structure.
64 These structures are defined in
65 \fIlwres/lwres.h\fR. They are shown below.
69 #define LWRES_OPCODE_NOOP 0x00000000U
77 lwres_uint16_t datalength;
79 } lwres_nooprequest_t;
87 lwres_uint16_t datalength;
89 } lwres_noopresponse_t;
94 Although the structures have different types, they are identical. This is because the no\-op opcode simply echos whatever data was sent: the response is therefore identical to the request.
96 \fBlwres_nooprequest_render()\fR
99 to convert no\-op request structure
101 to canonical format. The packet header structure
103 is initialised and transferred to buffer
104 \fIb\fR. The contents of
106 are then appended to the buffer in canonical format.
107 \fBlwres_noopresponse_render()\fR
108 performs the same task, except it converts a no\-op response structure
109 \fBlwres_noopresponse_t\fR
110 to the lightweight resolver's canonical format.
112 \fBlwres_nooprequest_parse()\fR
115 to convert the contents of packet
118 \fBlwres_nooprequest_t\fR
121 provides space to be used for storing this structure. When the function succeeds, the resulting
122 \fBlwres_nooprequest_t\fR
123 is made available through
125 \fBlwres_noopresponse_parse()\fR
126 offers the same semantics as
127 \fBlwres_nooprequest_parse()\fR
129 \fBlwres_noopresponse_t\fR
132 \fBlwres_noopresponse_free()\fR
134 \fBlwres_nooprequest_free()\fR
135 release the memory in resolver context
137 that was allocated to the
138 \fBlwres_noopresponse_t\fR
140 \fBlwres_nooprequest_t\fR
141 structures referenced via
145 The no\-op opcode functions
146 \fBlwres_nooprequest_render()\fR,
147 \fBlwres_noopresponse_render()\fR
148 \fBlwres_nooprequest_parse()\fR
150 \fBlwres_noopresponse_parse()\fR
152 \fBLWRES_R_SUCCESS\fR
153 on success. They return
154 \fBLWRES_R_NOMEMORY\fR
155 if memory allocation fails.
156 \fBLWRES_R_UNEXPECTEDEND\fR
157 is returned if the available space in the buffer
159 is too small to accommodate the packet header or the
160 \fBlwres_nooprequest_t\fR
162 \fBlwres_noopresponse_t\fR
164 \fBlwres_nooprequest_parse()\fR
166 \fBlwres_noopresponse_parse()\fR
168 \fBLWRES_R_UNEXPECTEDEND\fR
169 if the buffer is not empty after decoding the received packet. These functions will return
170 \fBLWRES_R_FAILURE\fR
173 in the packet header structure
174 \fBlwres_lwpacket_t\fR
175 indicate that the packet is not a response to an earlier query.
178 \fBlwres_packet\fR(3)
180 Copyright \(co 2004, 2005, 2007, 2012 Internet Systems Consortium, Inc. ("ISC")
182 Copyright \(co 2000, 2001 Internet Software Consortium.