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0710cbcd | 1 | /* |
bf95c10a | 2 | * Copyright (C) 1996-2022 The Squid Software Foundation and contributors |
0710cbcd | 3 | * |
0545caaa AJ |
4 | * Squid software is distributed under GPLv2+ license and includes |
5 | * contributions from numerous individuals and organizations. | |
6 | * Please see the COPYING and CONTRIBUTORS files for details. | |
0710cbcd | 7 | */ |
8 | ||
f7f3304a | 9 | #include "squid.h" |
4a3b98d7 AJ |
10 | #include "dns/rfc2671.h" |
11 | #include "dns/rfc3596.h" | |
0710cbcd | 12 | #include "util.h" |
13 | ||
0710cbcd | 14 | #if HAVE_UNISTD_H |
15 | #include <unistd.h> | |
16 | #endif | |
0710cbcd | 17 | #if HAVE_MEMORY_H |
18 | #include <memory.h> | |
19 | #endif | |
0710cbcd | 20 | #if HAVE_ASSERT_H |
21 | #include <assert.h> | |
22 | #endif | |
23 | #if HAVE_NETINET_IN_H | |
24 | #include <netinet/in.h> | |
25 | #endif | |
26 | #if HAVE_STRINGS_H | |
27 | #include <strings.h> | |
28 | #endif | |
29 | ||
0710cbcd | 30 | #ifndef SQUID_RFC1035_H |
31 | #error RFC3596 Library depends on RFC1035 | |
32 | #endif | |
33 | ||
0545caaa AJ |
34 | /* |
35 | * Low level DNS protocol routines | |
36 | * | |
37 | * Provides RFC3596 functions to handle purely IPv6 DNS. | |
38 | * Adds AAAA and IPv6 PTR records. | |
39 | * Other IPv6 records are not mentioned by this RFC. | |
40 | * | |
41 | * IPv4 equivalents are taken care of by the RFC1035 library. | |
42 | * Where one protocol lookup must be followed by another, the caller | |
2f8abb64 | 43 | * is responsible for the order and handling of the lookups. |
0545caaa AJ |
44 | * |
45 | * KNOWN BUGS: | |
46 | * | |
47 | * UDP replies with TC set should be retried via TCP | |
48 | */ | |
49 | ||
0710cbcd | 50 | /** |
51 | * Builds a message buffer with a QUESTION to lookup records | |
52 | * for a hostname. Caller must allocate 'buf' which should | |
53 | * probably be at least 512 octets. The 'szp' initially | |
54 | * specifies the size of the buffer, on return it contains | |
55 | * the size of the message (i.e. how much to write). | |
56 | * Returns the size of the query | |
57 | */ | |
58 | ssize_t | |
e210930b | 59 | rfc3596BuildHostQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, int qtype, ssize_t edns_sz) |
0710cbcd | 60 | { |
61 | static rfc1035_message h; | |
62 | size_t offset = 0; | |
63 | memset(&h, '\0', sizeof(h)); | |
64 | h.id = qid; | |
65 | h.qr = 0; | |
66 | h.rd = 1; | |
67 | h.opcode = 0; /* QUERY */ | |
68 | h.qdcount = (unsigned int) 1; | |
e210930b | 69 | h.arcount = (edns_sz > 0 ? 1 : 0); |
0710cbcd | 70 | offset += rfc1035HeaderPack(buf + offset, sz - offset, &h); |
71 | offset += rfc1035QuestionPack(buf + offset, | |
72 | sz - offset, | |
73 | hostname, | |
74 | qtype, | |
75 | RFC1035_CLASS_IN); | |
e210930b AJ |
76 | if (edns_sz > 0) |
77 | offset += rfc2671RROptPack(buf + offset, sz - offset, edns_sz); | |
0710cbcd | 78 | |
79 | if (query) { | |
80 | query->qtype = qtype; | |
81 | query->qclass = RFC1035_CLASS_IN; | |
82 | xstrncpy(query->name, hostname, sizeof(query->name)); | |
83 | } | |
84 | ||
85 | assert(offset <= sz); | |
86 | return offset; | |
87 | } | |
88 | ||
89 | /** | |
90 | * Builds a message buffer with a QUESTION to lookup A records | |
91 | * for a hostname. Caller must allocate 'buf' which should | |
92 | * probably be at least 512 octets. The 'szp' initially | |
93 | * specifies the size of the buffer, on return it contains | |
94 | * the size of the message (i.e. how much to write). | |
95 | * \return the size of the query | |
96 | */ | |
97 | ssize_t | |
e210930b | 98 | rfc3596BuildAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz) |
0710cbcd | 99 | { |
e210930b | 100 | return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_A, edns_sz); |
0710cbcd | 101 | } |
102 | ||
103 | /** | |
104 | * Builds a message buffer with a QUESTION to lookup AAAA records | |
105 | * for a hostname. Caller must allocate 'buf' which should | |
106 | * probably be at least 512 octets. The 'szp' initially | |
107 | * specifies the size of the buffer, on return it contains | |
108 | * the size of the message (i.e. how much to write). | |
109 | * \return the size of the query | |
110 | */ | |
111 | ssize_t | |
e210930b | 112 | rfc3596BuildAAAAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz) |
0710cbcd | 113 | { |
e210930b | 114 | return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_AAAA, edns_sz); |
0710cbcd | 115 | } |
116 | ||
0710cbcd | 117 | /** |
118 | * Builds a message buffer with a QUESTION to lookup PTR records | |
119 | * for an address. Caller must allocate 'buf' which should | |
120 | * probably be at least 512 octets. The 'szp' initially | |
121 | * specifies the size of the buffer, on return it contains | |
122 | * the size of the message (i.e. how much to write). | |
123 | * \return the size of the query | |
124 | */ | |
125 | ssize_t | |
e210930b | 126 | rfc3596BuildPTRQuery4(const struct in_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz) |
0710cbcd | 127 | { |
128 | static char rev[RFC1035_MAXHOSTNAMESZ]; | |
129 | unsigned int i; | |
130 | ||
131 | i = (unsigned int) ntohl(addr.s_addr); | |
132 | snprintf(rev, RFC1035_MAXHOSTNAMESZ, "%u.%u.%u.%u.in-addr.arpa.", | |
133 | i & 255, | |
134 | (i >> 8) & 255, | |
135 | (i >> 16) & 255, | |
136 | (i >> 24) & 255); | |
137 | ||
e210930b | 138 | return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR, edns_sz); |
0710cbcd | 139 | } |
140 | ||
141 | ssize_t | |
e210930b | 142 | rfc3596BuildPTRQuery6(const struct in6_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz) |
0710cbcd | 143 | { |
144 | static char rev[RFC1035_MAXHOSTNAMESZ]; | |
145 | const uint8_t* r = addr.s6_addr; | |
146 | char* p = rev; | |
b8031529 | 147 | int i; /* NP: MUST allow signed for loop termination. */ |
0710cbcd | 148 | |
149 | /* work from the raw addr field. anything else may have representation changes. */ | |
150 | /* The sin6_port and sin6_addr members shall be in network byte order. */ | |
26ac0430 | 151 | for (i = 15; i >= 0; i--, p+=4) { |
5c4e391c | 152 | snprintf(p, 5, "%1x.%1x.", ((r[i])&0xf), (r[i]>>4)&0xf ); |
0710cbcd | 153 | } |
154 | ||
155 | snprintf(p,10,"ip6.arpa."); | |
156 | ||
e210930b | 157 | return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR, edns_sz); |
0710cbcd | 158 | } |
159 |