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1 | /* |
2 | * This file is part of PowerDNS or dnsdist. | |
3 | * Copyright -- PowerDNS.COM B.V. and its contributors | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of version 2 of the GNU General Public License as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * In addition, for the avoidance of any doubt, permission is granted to | |
10 | * link this program with OpenSSL and to (re)distribute the binaries | |
11 | * produced as the result of such linking. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
21 | */ | |
22 | ||
23 | #include "dnsdist-xpf.hh" | |
24 | ||
25 | #include "dnsparser.hh" | |
26 | #include "xpf.hh" | |
27 | ||
28 | bool addXPF(DNSQuestion& dq, uint16_t optionCode, bool preserveTrailingData) | |
29 | { | |
30 | std::string payload = generateXPFPayload(dq.tcp, *dq.remote, *dq.local); | |
31 | uint8_t root = '\0'; | |
32 | dnsrecordheader drh; | |
33 | drh.d_type = htons(optionCode); | |
34 | drh.d_class = htons(QClass::IN); | |
35 | drh.d_ttl = 0; | |
36 | drh.d_clen = htons(payload.size()); | |
37 | size_t recordHeaderLen = sizeof(root) + sizeof(drh); | |
38 | ||
39 | size_t available = dq.size - dq.len; | |
40 | ||
41 | if ((payload.size() + recordHeaderLen) > available) { | |
42 | return false; | |
43 | } | |
44 | ||
45 | size_t xpfSize = sizeof(root) + sizeof(drh) + payload.size(); | |
46 | uint32_t realPacketLen = getDNSPacketLength(reinterpret_cast<const char*>(dq.dh), dq.len); | |
47 | if (realPacketLen < dq.len && preserveTrailingData) { | |
48 | size_t toMove = dq.len - realPacketLen; | |
49 | memmove(reinterpret_cast<char*>(dq.dh) + realPacketLen + xpfSize, reinterpret_cast<const char*>(dq.dh) + realPacketLen, toMove); | |
50 | dq.len += xpfSize; | |
51 | } | |
52 | else { | |
53 | dq.len = realPacketLen + xpfSize; | |
54 | } | |
55 | ||
56 | size_t pos = realPacketLen; | |
57 | memcpy(reinterpret_cast<char*>(dq.dh) + pos, &root, sizeof(root)); | |
58 | pos += sizeof(root); | |
59 | memcpy(reinterpret_cast<char*>(dq.dh) + pos, &drh, sizeof(drh)); | |
60 | pos += sizeof(drh); | |
61 | memcpy(reinterpret_cast<char*>(dq.dh) + pos, payload.data(), payload.size()); | |
62 | pos += payload.size(); | |
63 | ||
64 | dq.dh->arcount = htons(ntohs(dq.dh->arcount) + 1); | |
65 | ||
66 | return true; | |
67 | } |