246 lines
10 KiB
C++
246 lines
10 KiB
C++
/* $NetBSD: resolv.h,v 1.31 2005/12/26 19:01:47 perry Exp $ */
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/*
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* Copyright (c) 1983, 1987, 1989
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#pragma once
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#include <android-base/logging.h>
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#include <android-base/unique_fd.h>
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#include <private/android_filesystem_config.h> // AID_DNS
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#include <net/if.h>
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#include <time.h>
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#include <span>
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#include <string>
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#include <vector>
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#include "DnsResolver.h"
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#include "netd_resolv/resolv.h"
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#include "params.h"
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#include "stats.pb.h"
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// Linux defines MAXHOSTNAMELEN as 64, while the domain name limit in
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// RFC 1034 and RFC 1035 is 255 octets.
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#ifdef MAXHOSTNAMELEN
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#undef MAXHOSTNAMELEN
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#endif
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#define MAXHOSTNAMELEN 256
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/*
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* Global defines and variables for resolver stub.
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*/
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#define RES_TIMEOUT 5000 /* min. milliseconds between retries */
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#define RES_DFLRETRY 2 /* Default #/tries. */
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// Flags for ResState::flags
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#define RES_F_VC 0x00000001 // socket is TCP
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#define RES_F_EDNS0ERR 0x00000004 // EDNS0 caused errors
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#define RES_F_MDNS 0x00000008 // MDNS packet
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// Holds either a sockaddr_in or a sockaddr_in6.
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union sockaddr_union {
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struct sockaddr sa;
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struct sockaddr_in sin;
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struct sockaddr_in6 sin6;
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};
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constexpr int MAXPACKET = 8 * 1024;
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struct ResState {
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ResState(const android_net_context* netcontext, android::net::NetworkDnsEventReported* dnsEvent)
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: netid(netcontext->dns_netid),
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uid(netcontext->uid),
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pid(netcontext->pid),
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mark(netcontext->dns_mark),
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event(dnsEvent),
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netcontext_flags(netcontext->flags) {}
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ResState clone(android::net::NetworkDnsEventReported* dnsEvent = nullptr) {
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// TODO: Separate non-copyable members to other structures and let default copy
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// constructor do its work for below copyable members.
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ResState copy;
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copy.netid = netid;
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copy.uid = uid;
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copy.pid = pid;
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copy.search_domains = search_domains;
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copy.nsaddrs = nsaddrs;
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copy.ndots = ndots;
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copy.mark = mark;
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copy.flags = flags;
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copy.event = (dnsEvent == nullptr) ? event : dnsEvent;
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copy.netcontext_flags = netcontext_flags;
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copy.tc_mode = tc_mode;
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copy.enforce_dns_uid = enforce_dns_uid;
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copy.sort_nameservers = sort_nameservers;
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return copy;
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}
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void closeSockets() {
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tcp_nssock.reset();
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flags &= ~RES_F_VC;
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for (auto& sock : udpsocks) {
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sock.reset();
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}
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}
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int nameserverCount() { return nsaddrs.size(); }
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// clang-format off
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unsigned netid; // NetId: cache key and socket mark
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uid_t uid; // uid of the app that sent the DNS lookup
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pid_t pid; // pid of the app that sent the DNS lookup
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std::vector<std::string> search_domains{}; // domains to search
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std::vector<android::netdutils::IPSockAddr> nsaddrs;
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android::base::unique_fd udpsocks[MAXNS]; // UDP sockets to nameservers
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unsigned ndots : 4 = 1; // threshold for initial abs. query
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unsigned mark; // Socket mark to be used by all DNS query sockets
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android::base::unique_fd tcp_nssock; // TCP socket (but why not one per nameserver?)
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uint32_t flags = 0; // See RES_F_* defines below
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android::net::NetworkDnsEventReported* event;
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uint32_t netcontext_flags;
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int tc_mode = 0;
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bool enforce_dns_uid = false;
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bool sort_nameservers = false; // True if nsaddrs has been sorted.
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// clang-format on
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private:
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ResState() {}
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};
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/* End of stats related definitions */
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/*
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* Error code extending h_errno codes defined in bionic/libc/include/netdb.h.
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*
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* This error code, including legacy h_errno, is returned from res_nquery(), res_nsearch(),
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* res_nquerydomain(), res_queryN(), res_searchN() and res_querydomainN() for DNS metrics.
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*
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* TODO: Consider mapping legacy and extended h_errno into a unified resolver error code mapping.
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*/
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#define NETD_RESOLV_H_ERRNO_EXT_TIMEOUT RCODE_TIMEOUT
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extern const char* const _res_opcodes[];
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int res_nameinquery(const char*, int, int, const uint8_t*, const uint8_t*);
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int res_queriesmatch(const uint8_t*, const uint8_t*, const uint8_t*, const uint8_t*);
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int res_nquery(ResState*, const char*, int, int, std::span<uint8_t>, int*);
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int res_nsearch(ResState*, const char*, int, int, std::span<uint8_t>, int*);
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int res_nquerydomain(ResState*, const char*, const char*, int, int, std::span<uint8_t>, int*);
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int res_nmkquery(int op, const char* qname, int cl, int type, std::span<const uint8_t> data,
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std::span<uint8_t> msg, int netcontext_flags);
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int res_nsend(ResState* statp, std::span<const uint8_t> msg, std::span<uint8_t> ans, int* rcode,
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uint32_t flags, std::chrono::milliseconds sleepTimeMs = {});
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int res_nopt(ResState*, int, std::span<uint8_t>, int);
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int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,
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addrinfo** result);
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// Helper function for converting h_errno to the error codes visible to netd
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int herrnoToAiErrno(int herrno);
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// Helper function to enable MDNS resolution.
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void setMdnsFlag(std::string_view hostname, unsigned netid, uint32_t* flags);
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// Helper function for checking MDNS resolution is enabled or not.
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bool isMdnsResolution(uint32_t flags);
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// switch resolver log severity
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android::base::LogSeverity logSeverityStrToEnum(const std::string& logSeverityStr);
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template <typename Dest>
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Dest saturate_cast(int64_t x) {
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using DestLimits = std::numeric_limits<Dest>;
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if (x > DestLimits::max()) return DestLimits::max();
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if (x < DestLimits::min()) return DestLimits::min();
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return static_cast<Dest>(x);
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}
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constexpr bool is_power_of_2(size_t n) {
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return n != 0 && (n & (n - 1)) == 0;
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}
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// Rounds up a pointer to a char buffer |p| to a multiple of |Alignment| bytes.
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// Requirements:
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// |p| must be a pointer to a byte-sized type (e.g.: uint8_t)
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// |Alignment| must be a power of 2
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template<uintptr_t Alignment = sizeof(void*), typename T>
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requires (sizeof(T) == 1) && (is_power_of_2(Alignment))
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constexpr T* align_ptr(T* const p) {
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// Written this way to sidestep the performance-no-int-to-ptr clang-tidy warning.
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constexpr uintptr_t mask = Alignment - 1;
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const uintptr_t uintptr = reinterpret_cast<uintptr_t>(p);
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const uintptr_t aligned = (uintptr + mask) & ~mask;
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const uintptr_t bias = aligned - uintptr;
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return p + bias;
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}
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// Testcases for align_ptr()
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// TODO: enable when libc++ has std::bit_cast - reinterpret_cast isn't allowed in consteval context
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// static_assert(align_ptr((char*)1000) == (char*)1000);
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// static_assert(align_ptr((char*)1001) == (char*)1000 + sizeof(void*));
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// static_assert(align_ptr((char*)1003) == (char*)1000 + sizeof(void*));
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// static_assert(align_ptr<sizeof(uint32_t)>((char*)1004) == (char*)1004);
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// static_assert(align_ptr<sizeof(uint64_t)>((char*)1004) == (char*)1008);
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android::net::NsType getQueryType(std::span<const uint8_t> msg);
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android::net::IpVersion ipFamilyToIPVersion(int ipFamily);
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inline void resolv_tag_socket(int sock, uid_t uid, pid_t pid) {
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// This is effectively equivalent to testing for R+
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if (android::net::gResNetdCallbacks.tagSocket != nullptr) {
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if (int err = android::net::gResNetdCallbacks.tagSocket(sock, TAG_SYSTEM_DNS, uid, pid)) {
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LOG(WARNING) << "Failed to tag socket: " << strerror(-err);
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}
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}
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// fchown() apps' uid only in R+, since it's incompatible with Q's ebpf vpn isolation feature.
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if (fchown(sock, (android::net::gApiLevel >= 30) ? uid : AID_DNS, -1) == -1) {
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PLOG(WARNING) << "Failed to chown socket";
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}
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}
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