1 /* $NetBSD: resolv.h,v 1.31 2005/12/26 19:01:47 perry Exp $ */
2
3 /*
4 * Copyright (c) 1983, 1987, 1989
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
34 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
35 *
36 * Permission to use, copy, modify, and distribute this software for any
37 * purpose with or without fee is hereby granted, provided that the above
38 * copyright notice and this permission notice appear in all copies.
39 *
40 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
41 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
42 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
43 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
44 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
45 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
46 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
47 */
48
49 #pragma once
50
51 #include <android-base/logging.h>
52 #include <android-base/unique_fd.h>
53 #include <private/android_filesystem_config.h> // AID_DNS
54
55 #include <net/if.h>
56 #include <time.h>
57 #include <string>
58 #include <vector>
59
60 #include "DnsResolver.h"
61 #include "netd_resolv/resolv.h"
62 #include "params.h"
63 #include "stats.pb.h"
64
65 // Linux defines MAXHOSTNAMELEN as 64, while the domain name limit in
66 // RFC 1034 and RFC 1035 is 255 octets.
67 #ifdef MAXHOSTNAMELEN
68 #undef MAXHOSTNAMELEN
69 #endif
70 #define MAXHOSTNAMELEN 256
71
72 /*
73 * Global defines and variables for resolver stub.
74 */
75 #define RES_TIMEOUT 5000 /* min. milliseconds between retries */
76 #define RES_DFLRETRY 2 /* Default #/tries. */
77
78 // Flags for res_state->_flags
79 #define RES_F_VC 0x00000001 // socket is TCP
80 #define RES_F_EDNS0ERR 0x00000004 // EDNS0 caused errors
81
82 // Holds either a sockaddr_in or a sockaddr_in6.
83 union sockaddr_union {
84 struct sockaddr sa;
85 struct sockaddr_in sin;
86 struct sockaddr_in6 sin6;
87 };
88 constexpr int MAXPACKET = 8 * 1024;
89
90 struct ResState {
ResStateResState91 ResState(const android_net_context* netcontext, android::net::NetworkDnsEventReported* dnsEvent)
92 : netid(netcontext->dns_netid),
93 uid(netcontext->uid),
94 pid(netcontext->pid),
95 _mark(netcontext->dns_mark),
96 event(dnsEvent),
97 netcontext_flags(netcontext->flags) {}
98
99 ResState clone(android::net::NetworkDnsEventReported* dnsEvent = nullptr) {
100 // TODO: Separate non-copyable members to other structures and let default copy
101 // constructor do its work for below copyable members.
102 ResState copy;
103 copy.netid = netid;
104 copy.uid = uid;
105 copy.pid = pid;
106 copy.search_domains = search_domains;
107 copy.nsaddrs = nsaddrs;
108 copy.ndots = ndots;
109 copy._mark = _mark;
110 copy._flags = _flags;
111 copy.event = (dnsEvent == nullptr) ? event : dnsEvent;
112 copy.netcontext_flags = netcontext_flags;
113 copy.tc_mode = tc_mode;
114 copy.enforce_dns_uid = enforce_dns_uid;
115 copy.sort_nameservers = sort_nameservers;
116 return copy;
117 }
closeSocketsResState118 void closeSockets() {
119 tcp_nssock.reset();
120 _flags &= ~RES_F_VC;
121
122 for (auto& sock : nssocks) {
123 sock.reset();
124 }
125 }
126
nameserverCountResState127 int nameserverCount() { return nsaddrs.size(); }
128
129 // clang-format off
130 unsigned netid; // NetId: cache key and socket mark
131 uid_t uid; // uid of the app that sent the DNS lookup
132 pid_t pid; // pid of the app that sent the DNS lookup
133 std::vector<std::string> search_domains{}; // domains to search
134 std::vector<android::netdutils::IPSockAddr> nsaddrs;
135 android::base::unique_fd nssocks[MAXNS]; // UDP sockets to nameservers
136 unsigned ndots : 4 = 1; // threshold for initial abs. query
137 unsigned _mark; // If non-0 SET_MARK to _mark on all request sockets
138 android::base::unique_fd tcp_nssock; // TCP socket (but why not one per nameserver?)
139 uint32_t _flags = 0; // See RES_F_* defines below
140 android::net::NetworkDnsEventReported* event;
141 uint32_t netcontext_flags;
142 int tc_mode = 0;
143 bool enforce_dns_uid = false;
144 bool sort_nameservers = false; // A flag to indicate whether nsaddrs has been
145 // sorted or not.
146 // clang-format on
147 private:
ResStateResState148 ResState() {}
149 };
150
151 // TODO: remove these legacy aliases
152 typedef ResState* res_state;
153
154 /* End of stats related definitions */
155
156 /*
157 * Error code extending h_errno codes defined in bionic/libc/include/netdb.h.
158 *
159 * This error code, including legacy h_errno, is returned from res_nquery(), res_nsearch(),
160 * res_nquerydomain(), res_queryN(), res_searchN() and res_querydomainN() for DNS metrics.
161 *
162 * TODO: Consider mapping legacy and extended h_errno into a unified resolver error code mapping.
163 */
164 #define NETD_RESOLV_H_ERRNO_EXT_TIMEOUT RCODE_TIMEOUT
165
166 extern const char* const _res_opcodes[];
167
168 int res_nameinquery(const char*, int, int, const uint8_t*, const uint8_t*);
169 int res_queriesmatch(const uint8_t*, const uint8_t*, const uint8_t*, const uint8_t*);
170
171 int res_nquery(res_state, const char*, int, int, uint8_t*, int, int*);
172 int res_nsearch(res_state, const char*, int, int, uint8_t*, int, int*);
173 int res_nquerydomain(res_state, const char*, const char*, int, int, uint8_t*, int, int*);
174 int res_nmkquery(int op, const char* qname, int cl, int type, const uint8_t* data, int datalen,
175 uint8_t* buf, int buflen, int netcontext_flags);
176 int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int anssiz, int* rcode,
177 uint32_t flags, std::chrono::milliseconds sleepTimeMs = {});
178 int res_nopt(res_state, int, uint8_t*, int, int);
179
180 int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,
181 addrinfo** result);
182
183 // Helper function for converting h_errno to the error codes visible to netd
184 int herrnoToAiErrno(int herrno);
185
186 // switch resolver log severity
187 android::base::LogSeverity logSeverityStrToEnum(const std::string& logSeverityStr);
188
189 template <typename Dest>
saturate_cast(int64_t x)190 Dest saturate_cast(int64_t x) {
191 using DestLimits = std::numeric_limits<Dest>;
192 if (x > DestLimits::max()) return DestLimits::max();
193 if (x < DestLimits::min()) return DestLimits::min();
194 return static_cast<Dest>(x);
195 }
196
197 android::net::NsType getQueryType(const uint8_t* msg, size_t msgLen);
198
199 android::net::IpVersion ipFamilyToIPVersion(int ipFamily);
200
resolv_tag_socket(int sock,uid_t uid,pid_t pid)201 inline void resolv_tag_socket(int sock, uid_t uid, pid_t pid) {
202 // This is effectively equivalent to testing for R+
203 if (android::net::gResNetdCallbacks.tagSocket != nullptr) {
204 if (int err = android::net::gResNetdCallbacks.tagSocket(sock, TAG_SYSTEM_DNS, uid, pid)) {
205 LOG(WARNING) << "Failed to tag socket: " << strerror(-err);
206 }
207 }
208
209 // fchown() apps' uid only in R+, since it's incompatible with Q's ebpf vpn isolation feature.
210 if (fchown(sock, (android::net::gApiLevel >= 30) ? uid : AID_DNS, -1) == -1) {
211 PLOG(WARNING) << "Failed to chown socket";
212 }
213 }
214