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/* $NetBSD: resolv.h,v 1.31 2005/12/26 19:01:47 perry Exp $ */
/*
* Copyright (c) 1983, 1987, 1989
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#pragma once
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
#include <private/android_filesystem_config.h> // AID_DNS
#include <net/if.h>
#include <time.h>
#include <string>
#include <vector>
#include "DnsResolver.h"
#include "netd_resolv/resolv.h"
#include "params.h"
#include "stats.pb.h"
// Linux defines MAXHOSTNAMELEN as 64, while the domain name limit in
// RFC 1034 and RFC 1035 is 255 octets.
#ifdef MAXHOSTNAMELEN
#undef MAXHOSTNAMELEN
#endif
#define MAXHOSTNAMELEN 256
/*
* Global defines and variables for resolver stub.
*/
#define RES_TIMEOUT 5000 /* min. milliseconds between retries */
#define RES_DFLRETRY 2 /* Default #/tries. */
// Flags for res_state->_flags
#define RES_F_VC 0x00000001 // socket is TCP
#define RES_F_EDNS0ERR 0x00000004 // EDNS0 caused errors
// Holds either a sockaddr_in or a sockaddr_in6.
union sockaddr_union {
struct sockaddr sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
};
constexpr int MAXPACKET = 8 * 1024;
struct ResState {
ResState(const android_net_context* netcontext, android::net::NetworkDnsEventReported* dnsEvent)
: netid(netcontext->dns_netid),
uid(netcontext->uid),
pid(netcontext->pid),
_mark(netcontext->dns_mark),
event(dnsEvent),
netcontext_flags(netcontext->flags) {}
ResState clone(android::net::NetworkDnsEventReported* dnsEvent = nullptr) {
// TODO: Separate non-copyable members to other structures and let default copy
// constructor do its work for below copyable members.
ResState copy;
copy.netid = netid;
copy.uid = uid;
copy.pid = pid;
copy.search_domains = search_domains;
copy.nsaddrs = nsaddrs;
copy.ndots = ndots;
copy._mark = _mark;
copy._flags = _flags;
copy.event = (dnsEvent == nullptr) ? event : dnsEvent;
copy.netcontext_flags = netcontext_flags;
copy.tc_mode = tc_mode;
copy.enforce_dns_uid = enforce_dns_uid;
copy.sort_nameservers = sort_nameservers;
return copy;
}
void closeSockets() {
tcp_nssock.reset();
_flags &= ~RES_F_VC;
for (auto& sock : nssocks) {
sock.reset();
}
}
int nameserverCount() { return nsaddrs.size(); }
// clang-format off
unsigned netid; // NetId: cache key and socket mark
uid_t uid; // uid of the app that sent the DNS lookup
pid_t pid; // pid of the app that sent the DNS lookup
std::vector<std::string> search_domains{}; // domains to search
std::vector<android::netdutils::IPSockAddr> nsaddrs;
android::base::unique_fd nssocks[MAXNS]; // UDP sockets to nameservers
unsigned ndots : 4 = 1; // threshold for initial abs. query
unsigned _mark; // If non-0 SET_MARK to _mark on all request sockets
android::base::unique_fd tcp_nssock; // TCP socket (but why not one per nameserver?)
uint32_t _flags = 0; // See RES_F_* defines below
android::net::NetworkDnsEventReported* event;
uint32_t netcontext_flags;
int tc_mode = 0;
bool enforce_dns_uid = false;
bool sort_nameservers = false; // A flag to indicate whether nsaddrs has been
// sorted or not.
// clang-format on
private:
ResState() {}
};
// TODO: remove these legacy aliases
typedef ResState* res_state;
/* End of stats related definitions */
/*
* Error code extending h_errno codes defined in bionic/libc/include/netdb.h.
*
* This error code, including legacy h_errno, is returned from res_nquery(), res_nsearch(),
* res_nquerydomain(), res_queryN(), res_searchN() and res_querydomainN() for DNS metrics.
*
* TODO: Consider mapping legacy and extended h_errno into a unified resolver error code mapping.
*/
#define NETD_RESOLV_H_ERRNO_EXT_TIMEOUT RCODE_TIMEOUT
extern const char* const _res_opcodes[];
int res_nameinquery(const char*, int, int, const uint8_t*, const uint8_t*);
int res_queriesmatch(const uint8_t*, const uint8_t*, const uint8_t*, const uint8_t*);
int res_nquery(res_state, const char*, int, int, uint8_t*, int, int*);
int res_nsearch(res_state, const char*, int, int, uint8_t*, int, int*);
int res_nquerydomain(res_state, const char*, const char*, int, int, uint8_t*, int, int*);
int res_nmkquery(int op, const char* qname, int cl, int type, const uint8_t* data, int datalen,
uint8_t* buf, int buflen, int netcontext_flags);
int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int anssiz, int* rcode,
uint32_t flags, std::chrono::milliseconds sleepTimeMs = {});
int res_nopt(res_state, int, uint8_t*, int, int);
int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,
addrinfo** result);
// Helper function for converting h_errno to the error codes visible to netd
int herrnoToAiErrno(int herrno);
// switch resolver log severity
android::base::LogSeverity logSeverityStrToEnum(const std::string& logSeverityStr);
template <typename Dest>
Dest saturate_cast(int64_t x) {
using DestLimits = std::numeric_limits<Dest>;
if (x > DestLimits::max()) return DestLimits::max();
if (x < DestLimits::min()) return DestLimits::min();
return static_cast<Dest>(x);
}
android::net::NsType getQueryType(const uint8_t* msg, size_t msgLen);
android::net::IpVersion ipFamilyToIPVersion(int ipFamily);
inline void resolv_tag_socket(int sock, uid_t uid, pid_t pid) {
// This is effectively equivalent to testing for R+
if (android::net::gResNetdCallbacks.tagSocket != nullptr) {
if (int err = android::net::gResNetdCallbacks.tagSocket(sock, TAG_SYSTEM_DNS, uid, pid)) {
LOG(WARNING) << "Failed to tag socket: " << strerror(-err);
}
}
// fchown() apps' uid only in R+, since it's incompatible with Q's ebpf vpn isolation feature.
if (fchown(sock, (android::net::gApiLevel >= 30) ? uid : AID_DNS, -1) == -1) {
PLOG(WARNING) << "Failed to chown socket";
}
}