dnsmasq/src/config.h

/* dnsmasq is Copyright (c) 2000-2024 Simon Kelley

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 dated June, 1991, or
   (at your option) version 3 dated 29 June, 2007.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
     
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#define FTABSIZ 150 /* max number of outstanding requests (default) */
#define MAX_PROCS 20 /* default max no children for TCP requests */
#define CHILD_LIFETIME 150 /* secs 'till terminated (RFC1035 suggests > 120s) */
#define TCP_MAX_QUERIES 100 /* Maximum number of queries per incoming TCP connection */
#define TCP_BACKLOG 32  /* kernel backlog limit for TCP connections */
#define EDNS_PKTSZ 1232 /* default max EDNS.0 UDP packet from from  /dnsflagday.net/2020 */
#define SAFE_PKTSZ 1232 /* "go anywhere" UDP packet size, see https://dnsflagday.net/2020/ */
#define KEYBLOCK_LEN 40 /* choose to minimise fragmentation when storing DNSSEC keys */
#define DNSSEC_WORK 50 /* Max number of queries to validate one question */
#define LIMIT_KEY_FAIL 15 /* Number of keys that can fail DS validate in one an answer. */
#define LIMIT_DS_FAIL 5   /* Number of DS records that can fail to validate a key in one answer */
#define LIMIT_SIG_FAIL 10 /* Number of signature that can fail to validate in one answer */
#define LIMIT_CRYPTO 40   /* max no. of crypto operations to validate one a query. */
#define LIMIT_NSEC3_ITERS 150 /* Max. number if iterations allow in NSEC3 record. */
#define TIMEOUT 10     /* drop UDP queries after TIMEOUT seconds */
#define SMALL_PORT_RANGE 30 /* If DNS port range is smaller than this, use different allocation. */
#define FORWARD_TEST 50 /* try all servers every 50 queries */
#define FORWARD_TIME 20 /* or 20 seconds */
#define UDP_TEST_TIME 60 /* How often to reset our idea of max packet size. */
#define SERVERS_LOGGED 30 /* Only log this many servers when logging state */
#define LOCALS_LOGGED 8 /* Only log this many local addresses when logging state */
#define LEASE_RETRY 60 /* on error, retry writing leasefile after LEASE_RETRY seconds */
#define CACHESIZ 150 /* default cache size */
#define TTL_FLOOR_LIMIT 3600 /* don't allow --min-cache-ttl to raise TTL above this under any circumstances */
#define MAXLEASES 1000 /* maximum number of DHCP leases */
#define PING_WAIT 3 /* wait for ping address-in-use test */
#define PING_CACHE_TIME 30 /* Ping test assumed to be valid this long. */
#define DECLINE_BACKOFF 600 /* disable DECLINEd static addresses for this long */
#define DHCP_PACKET_MAX 16384 /* hard limit on DHCP packet size */
#define SMALLDNAME 50 /* most domain names are smaller than this */
#define CNAME_CHAIN 10 /* chains longer than this atr dropped for loop protection */
#define DNSSEC_MIN_TTL 60 /* DNSKEY and DS records in cache last at least this long */
#define HOSTSFILE "/etc/hosts"
#define ETHERSFILE "/etc/ethers"
#define DEFLEASE 3600 /* default DHCPv4 lease time, one hour */
#define DEFLEASE6 (3600*24) /* default lease time for DHCPv6. One day. */
#define CHUSER "nobody"
#define CHGRP "dip"
#define TFTP_MAX_CONNECTIONS 50 /* max simultaneous connections */
#define LOG_MAX 5 /* log-queue length */
#define RANDFILE "/dev/urandom"
#define DNSMASQ_SERVICE "uk.org.thekelleys.dnsmasq" /* Default - may be overridden by config */
#define DNSMASQ_PATH "/uk/org/thekelleys/dnsmasq"
#define DNSMASQ_UBUS_NAME "dnsmasq" /* Default - may be overridden by config */
#define AUTH_TTL 600 /* default TTL for auth DNS */
#define SOA_REFRESH 1200 /* SOA refresh default */
#define SOA_RETRY 180 /* SOA retry default */
#define SOA_EXPIRY 1209600 /* SOA expiry default */
#define LOOP_TEST_DOMAIN "test" /* domain for loop testing, "test" is reserved by RFC 2606 and won't therefore clash */
#define LOOP_TEST_TYPE T_TXT
#define DEFAULT_FAST_RETRY 1000 /* ms, default delay before fast retry */
#define STALE_CACHE_EXPIRY 86400 /* 1 day in secs, default maximum expiry time for stale cache data */
 
/* compile-time options: uncomment below to enable or do eg.
   make COPTS=-DHAVE_BROKEN_RTC

HAVE_BROKEN_RTC
   define this on embedded systems which don't have an RTC
   which keeps time over reboots. Causes dnsmasq to use uptime
   for timing, and keep lease lengths rather than expiry times
   in its leases file. This also make dnsmasq "flash disk friendly".
   Normally, dnsmasq tries very hard to keep the on-disk leases file
   up-to-date: rewriting it after every renewal.  When HAVE_BROKEN_RTC 
   is in effect, the lease file is only written when a new lease is 
   created, or an old one destroyed. (Because those are the only times 
   it changes.) This vastly reduces the number of file writes, and makes
   it viable to keep the lease file on a flash filesystem.
   NOTE: when enabling or disabling this, be sure to delete any old
   leases file, otherwise dnsmasq may get very confused.

HAVE_TFTP
   define this to get dnsmasq's built-in TFTP server.

HAVE_DHCP
   define this to get dnsmasq's DHCPv4 server.

HAVE_DHCP6
   define this to get dnsmasq's DHCPv6 server. (implies HAVE_DHCP).

HAVE_SCRIPT
   define this to get the ability to call scripts on lease-change.

HAVE_LUASCRIPT
   define this to get the ability to call Lua script on lease-change. (implies HAVE_SCRIPT) 

HAVE_DBUS
   define this if you want to link against libdbus, and have dnsmasq
   support some methods to allow (re)configuration of the upstream DNS 
   servers via DBus.

HAVE_UBUS
   define this if you want to link against libubus

HAVE_IDN
   define this if you want international domain name 2003 support.
   
HAVE_LIBIDN2
   define this if you want international domain name 2008 support.

HAVE_CONNTRACK
   define this to include code which propagates conntrack marks from
   incoming DNS queries to the corresponding upstream queries. This adds
   a build-dependency on libnetfilter_conntrack, but the resulting binary will
   still run happily on a kernel without conntrack support.

HAVE_IPSET
    define this to include the ability to selectively add resolved ip addresses
    to given ipsets.

HAVE_NFTSET
    define this to include the ability to selectively add resolved ip addresses
    to given nftables sets.

HAVE_AUTH
   define this to include the facility to act as an authoritative DNS
   server for one or more zones.

HAVE_CRYPTOHASH
   include just hash function from crypto library, but no DNSSEC.

HAVE_DNSSEC
   include DNSSEC validator.

HAVE_DUMPFILE
   include code to dump packets to a libpcap-format file for debugging.

HAVE_LOOP
   include functionality to probe for and remove DNS forwarding loops.

HAVE_INOTIFY
   use the Linux inotify facility to efficiently re-read configuration files.

NO_ID
   Don't report *.bind CHAOS info to clients, forward such requests upstream instead.
NO_TFTP
NO_DHCP
NO_DHCP6
NO_SCRIPT
NO_LARGEFILE
NO_AUTH
NO_DUMPFILE
NO_LOOP
NO_INOTIFY
   these are available to explicitly disable compile time options which would 
   otherwise be enabled automatically or which are enabled  by default 
   in the distributed source tree. Building dnsmasq
   with something like "make COPTS=-DNO_SCRIPT" will do the trick.
NO_GMP
   Don't use and link against libgmp, Useful if nettle is built with --enable-mini-gmp.

LEASEFILE
CONFFILE
RESOLVFILE
   the default locations of these files are determined below, but may be overridden 
   in a build command line using COPTS.

*/

/* Defining this builds a binary which handles time differently and works better on a system without a 
   stable RTC (it uses uptime, not epoch time) and writes the DHCP leases file less often to avoid flash wear. 
*/

/* #define HAVE_BROKEN_RTC */

/* The default set of options to build. Built with these options, dnsmasq
   has no library dependencies other than libc */

#define HAVE_DHCP
#define HAVE_DHCP6 
#define HAVE_TFTP
#define HAVE_SCRIPT
#define HAVE_AUTH
#define HAVE_IPSET 
#define HAVE_LOOP
#define HAVE_DUMPFILE

/* Build options which require external libraries.
   
   Defining HAVE_<opt>_STATIC as _well_ as HAVE_<opt> will link the library statically.

   You can use "make COPTS=-DHAVE_<opt>" instead of editing these.
*/

/* #define HAVE_LUASCRIPT */
/* #define HAVE_DBUS */
/* #define HAVE_IDN */
/* #define HAVE_LIBIDN2 */
/* #define HAVE_CONNTRACK */
/* #define HAVE_CRYPTOHASH */
/* #define HAVE_DNSSEC */
/* #define HAVE_NFTSET */

/* Default locations for important system files. */

#ifndef LEASEFILE
#   if defined(__FreeBSD__) || defined (__OpenBSD__) || defined(__DragonFly__) || defined(__NetBSD__)
#      define LEASEFILE "/var/db/dnsmasq.leases"
#   elif defined(__sun__) || defined (__sun)
#      define LEASEFILE "/var/cache/dnsmasq.leases"
#   elif defined(__ANDROID__)
#      define LEASEFILE "/data/misc/dhcp/dnsmasq.leases"
#   else
#      define LEASEFILE "/var/lib/misc/dnsmasq.leases"
#   endif
#endif

#ifndef CONFFILE
#   if defined(__FreeBSD__)
#      define CONFFILE "/usr/local/etc/dnsmasq.conf"
#   else
#      define CONFFILE "/etc/dnsmasq.conf"
#   endif
#endif

#ifndef RESOLVFILE
#   if defined(__uClinux__)
#      define RESOLVFILE "/etc/config/resolv.conf"
#   else
#      define RESOLVFILE "/etc/resolv.conf"
#   endif
#endif

#ifndef RUNFILE
#   if defined(__ANDROID__)
#      define RUNFILE "/data/dnsmasq.pid"
#    else
#      define RUNFILE "/var/run/dnsmasq.pid"
#    endif
#endif

/* platform dependent options: these are determined automatically below

HAVE_LINUX_NETWORK
HAVE_BSD_NETWORK
HAVE_SOLARIS_NETWORK
   define exactly one of these to alter interaction with kernel networking.

HAVE_GETOPT_LONG
   defined when GNU-style getopt_long available. 

HAVE_SOCKADDR_SA_LEN
   defined if struct sockaddr has sa_len field (*BSD) 
*/

#if defined(__UCLIBC__)
#define HAVE_LINUX_NETWORK
#if defined(__UCLIBC_HAS_GNU_GETOPT__) || \
   ((__UCLIBC_MAJOR__==0) && (__UCLIBC_MINOR__==9) && (__UCLIBC_SUBLEVEL__<21))
#    define HAVE_GETOPT_LONG
#endif
#undef HAVE_SOCKADDR_SA_LEN
#if defined(__UCLIBC_HAS_IPV6__)
#  ifndef IPV6_V6ONLY
#    define IPV6_V6ONLY 26
#  endif
#endif

/* This is for glibc 2.x */
#elif defined(__linux__)
#define HAVE_LINUX_NETWORK
#define HAVE_GETOPT_LONG
#undef HAVE_SOCKADDR_SA_LEN

#elif defined(__FreeBSD__) || \
      defined(__OpenBSD__) || \
      defined(__DragonFly__) || \
      defined(__FreeBSD_kernel__)
#define HAVE_BSD_NETWORK
/* Later versions of FreeBSD have getopt_long() */
#if defined(optional_argument) && defined(required_argument)
#   define HAVE_GETOPT_LONG
#endif
#define HAVE_SOCKADDR_SA_LEN

#elif defined(__APPLE__)
#define HAVE_BSD_NETWORK
#define HAVE_GETOPT_LONG
#define HAVE_SOCKADDR_SA_LEN
#define NO_IPSET
/* Define before sys/socket.h is included so we get socklen_t */
#define _BSD_SOCKLEN_T_
/* Select the RFC_3542 version of the IPv6 socket API. 
   Define before netinet6/in6.h is included. */
#define __APPLE_USE_RFC_3542
/* Required for Mojave. */
#ifndef SOL_TCP
#  define SOL_TCP IPPROTO_TCP
#endif
#define NO_IPSET

#elif defined(__NetBSD__)
#define HAVE_BSD_NETWORK
#define HAVE_GETOPT_LONG
#define HAVE_SOCKADDR_SA_LEN

#elif defined(__sun) || defined(__sun__)
#define HAVE_SOLARIS_NETWORK
#define HAVE_GETOPT_LONG
#undef HAVE_SOCKADDR_SA_LEN
#define ETHER_ADDR_LEN 6 
 
#endif

/* rules to implement compile-time option dependencies and 
   the NO_XXX flags */

#ifdef NO_TFTP
#undef HAVE_TFTP
#endif

#ifdef NO_DHCP
#undef HAVE_DHCP
#undef HAVE_DHCP6
#endif

#if defined(NO_DHCP6)
#undef HAVE_DHCP6
#endif

/* DHCP6 needs DHCP too */
#ifdef HAVE_DHCP6
#define HAVE_DHCP
#endif

#if defined(NO_SCRIPT)
#undef HAVE_SCRIPT
#undef HAVE_LUASCRIPT
#endif

/* Must HAVE_SCRIPT to HAVE_LUASCRIPT */
#ifdef HAVE_LUASCRIPT
#define HAVE_SCRIPT
#endif

#ifdef NO_AUTH
#undef HAVE_AUTH
#endif

#if defined(NO_IPSET)
#undef HAVE_IPSET
#endif

#ifdef NO_LOOP
#undef HAVE_LOOP
#endif

#ifdef NO_DUMPFILE
#undef HAVE_DUMPFILE
#endif

#if defined (HAVE_LINUX_NETWORK) && !defined(NO_INOTIFY)
#define HAVE_INOTIFY
#endif

/* Define a string indicating which options are in use.
   DNSMASQ_COMPILE_OPTS is only defined in dnsmasq.c */

#ifdef DNSMASQ_COMPILE_OPTS

static char *compile_opts = 
"IPv6 "
#ifndef HAVE_GETOPT_LONG
"no-"
#endif
"GNU-getopt "
#ifdef HAVE_BROKEN_RTC
"no-RTC "
#endif
#ifndef HAVE_DBUS
"no-"
#endif
"DBus "
#ifndef HAVE_UBUS
"no-"
#endif
"UBus "
#ifndef LOCALEDIR
"no-"
#endif
"i18n "
#if defined(HAVE_LIBIDN2)
"IDN2 "
#else
 #if !defined(HAVE_IDN)
"no-"
 #endif 
"IDN " 
#endif
#ifndef HAVE_DHCP
"no-"
#endif
"DHCP "
#if defined(HAVE_DHCP)
#  if !defined (HAVE_DHCP6)
     "no-"
#  endif  
     "DHCPv6 "
#endif
#if !defined(HAVE_SCRIPT)
     "no-scripts "
#else
#  if !defined(HAVE_LUASCRIPT)
     "no-"
#  endif
     "Lua "
#endif
#ifndef HAVE_TFTP
"no-"
#endif
"TFTP "
#ifndef HAVE_CONNTRACK
"no-"
#endif
"conntrack "
#ifndef HAVE_IPSET
"no-"
#endif
"ipset "
#ifndef HAVE_NFTSET
"no-"
#endif
"nftset "
#ifndef HAVE_AUTH
"no-"
#endif
"auth "
#if !defined(HAVE_CRYPTOHASH) && !defined(HAVE_DNSSEC)
"no-"
#endif
"cryptohash "
#ifndef HAVE_DNSSEC
"no-"
#endif
"DNSSEC "
#ifdef NO_ID
"no-ID "
#endif
#ifndef HAVE_LOOP
"no-"
#endif
"loop-detect "
#ifndef HAVE_INOTIFY
"no-"
#endif
"inotify "
#ifndef HAVE_DUMPFILE
"no-"
#endif
"dumpfile";

#endif /* defined(HAVE_DHCP) */