1 /*
2 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3 *
4 * This Source Code Form is subject to the terms of the Mozilla Public
5 * License, v. 2.0. If a copy of the MPL was not distributed with this
6 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
7 *
8 * See the COPYRIGHT file distributed with this work for additional
9 * information regarding copyright ownership.
10 */
11
12 /*! \file */
13
14 /**
15 * These functions rely on a struct lwres_lwpacket which is defined in
16 * \link lwpacket.h lwres/lwpacket.h.\endlink
17 *
18 * The following opcodes are currently defined:
19 *
20 * \li #LWRES_OPCODE_NOOP
21 * Success is always returned and the packet contents are
22 * echoed. The \link lwres_noop.c lwres_noop_*()\endlink functions should be used for this
23 * type.
24 *
25 * \li #LWRES_OPCODE_GETADDRSBYNAME
26 * returns all known addresses for a given name. The
27 * \link lwres_gabn.c lwres_gabn_*()\endlink functions should be used for this type.
28 *
29 * \li #LWRES_OPCODE_GETNAMEBYADDR
30 * return the hostname for the given address. The
31 * \link lwres_gnba.c lwres_gnba_*() \endlink functions should be used for this type.
32 *
33 * lwres_lwpacket_renderheader() transfers the contents of lightweight
34 * resolver packet structure #lwres_lwpacket_t *pkt in network byte
35 * order to the lightweight resolver buffer, *b.
36 *
37 * lwres_lwpacket_parseheader() performs the converse operation. It
38 * transfers data in network byte order from buffer *b to resolver
39 * packet *pkt. The contents of the buffer b should correspond to a
40 * #lwres_lwpacket_t.
41 *
42 * \section lwpacket_return Return Values
43 *
44 * Successful calls to lwres_lwpacket_renderheader() and
45 * lwres_lwpacket_parseheader() return #LWRES_R_SUCCESS. If there is
46 * insufficient space to copy data between the buffer *b and
47 * lightweight resolver packet *pkt both functions return
48 * #LWRES_R_UNEXPECTEDEND.
49 */
50
51 #include <config.h>
52
53 #include <assert.h>
54 #include <inttypes.h>
55 #include <stdlib.h>
56 #include <string.h>
57
58 #include <lwres/lwbuffer.h>
59 #include <lwres/lwpacket.h>
60 #include <lwres/result.h>
61
62 #include "assert_p.h"
63
64 /*% Length of Packet */
65 #define LWPACKET_LENGTH \
66 (sizeof(uint16_t) * 4 + sizeof(uint32_t) * 5)
67
68 /*% transfers the contents of lightweight resolver packet structure lwres_lwpacket_t *pkt in network byte order to the lightweight resolver buffer, *b. */
69
70 lwres_result_t
lwres_lwpacket_renderheader(lwres_buffer_t * b,lwres_lwpacket_t * pkt)71 lwres_lwpacket_renderheader(lwres_buffer_t *b, lwres_lwpacket_t *pkt) {
72 REQUIRE(b != NULL);
73 REQUIRE(pkt != NULL);
74
75 if (!SPACE_OK(b, LWPACKET_LENGTH))
76 return (LWRES_R_UNEXPECTEDEND);
77
78 lwres_buffer_putuint32(b, pkt->length);
79 lwres_buffer_putuint16(b, pkt->version);
80 lwres_buffer_putuint16(b, pkt->pktflags);
81 lwres_buffer_putuint32(b, pkt->serial);
82 lwres_buffer_putuint32(b, pkt->opcode);
83 lwres_buffer_putuint32(b, pkt->result);
84 lwres_buffer_putuint32(b, pkt->recvlength);
85 lwres_buffer_putuint16(b, pkt->authtype);
86 lwres_buffer_putuint16(b, pkt->authlength);
87
88 return (LWRES_R_SUCCESS);
89 }
90
91 /*% transfers data in network byte order from buffer *b to resolver packet *pkt. The contents of the buffer b should correspond to a lwres_lwpacket_t. */
92
93 lwres_result_t
lwres_lwpacket_parseheader(lwres_buffer_t * b,lwres_lwpacket_t * pkt)94 lwres_lwpacket_parseheader(lwres_buffer_t *b, lwres_lwpacket_t *pkt) {
95 uint32_t space;
96
97 REQUIRE(b != NULL);
98 REQUIRE(pkt != NULL);
99
100 space = LWRES_BUFFER_REMAINING(b);
101 if (space < LWPACKET_LENGTH)
102 return (LWRES_R_UNEXPECTEDEND);
103
104 pkt->length = lwres_buffer_getuint32(b);
105 /*
106 * XXXBEW/MLG Checking that the buffer is long enough probably
107 * shouldn't be done here, since this function is supposed to just
108 * parse the header.
109 */
110 if (pkt->length > space)
111 return (LWRES_R_UNEXPECTEDEND);
112 pkt->version = lwres_buffer_getuint16(b);
113 pkt->pktflags = lwres_buffer_getuint16(b);
114 pkt->serial = lwres_buffer_getuint32(b);
115 pkt->opcode = lwres_buffer_getuint32(b);
116 pkt->result = lwres_buffer_getuint32(b);
117 pkt->recvlength = lwres_buffer_getuint32(b);
118 pkt->authtype = lwres_buffer_getuint16(b);
119 pkt->authlength = lwres_buffer_getuint16(b);
120
121 return (LWRES_R_SUCCESS);
122 }
123