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dns based ad/abuse domain blocking

Description

A lot of people already use adblocker plugins within their desktop browsers, but what if you are using your (smart) phone, tablet, watch or any other wlan gadget...getting rid of annoying ads, trackers and other abuse sites (like facebook ;-) is simple: block them with your router. When the dns server on your router receives dns requests, you will sort out queries that ask for the resource records of ad servers and return a simple 'NXDOMAIN'. This is nothing but Non-eXistent Internet or Intranet domain name, if domain name is unable to resolved using the dns server, a condition called the 'NXDOMAIN' occurred.

Main Features

support of the following domain block list sources (free for private usage, for commercial use please check their individual licenses):
- adaway
- => infrequent updates, approx. 400 entries (enabled by default)
- adguard
- => numerous updates on the same day, approx. 12.000 entries
- blacklist
- => static local blacklist, located by default in '/etc/adblock/adblock.blacklist'
- disconnect
- => numerous updates on the same day, approx. 6.500 entries (enabled by default)
- dshield
- => daily updates, approx. 4.500 entries
- feodotracker
- => daily updates, approx. 0-10 entries
- hphosts
- => monthly updates, approx. 50.000 entries
- malwaredomains
- => daily updates, approx. 16.000 entries
- malwaredomainlist
- => daily updates, approx. 1.500 entries
- openphish
- => numerous updates on the same day, approx. 1.800 entries
- palevo tracker
- => daily updates, approx. 15 entries
- ransomware tracker
- => daily updates, approx. 150 entries
- rolist/easylist
- => weekly updates, approx. 600 entries
- ruadlist/easylist
- => weekly updates, approx. 2.000 entries
- securemecca
- => infrequent updates, approx. 25.000 entries
- shallalist (categories "adv" "costtraps" "spyware" "tracker" "warez" enabled by default)
- => daily updates, approx. 32.000 entries (a short description of all shallalist categories can be found online)
- spam404
- => infrequent updates, approx. 5.000 entries
- sysctl/cameleon
- => weekly updates, approx. 21.000 entries
- whocares
- => weekly updates, approx. 12.000 entries
- winhelp
- => infrequent updates, approx. 15.000 entries
- winspy
- => infrequent updates, approx. 120 entries
- yoyo
- => weekly updates, approx. 2.500 entries (enabled by default)
- zeus tracker
- => daily updates, approx. 440 entries
zero-conf like automatic installation & setup, usually no manual changes needed
simple but yet powerful adblock engine: adblock does not use error prone external iptables rulesets, http pixel server instances and things like that
automatically selects dnsmasq or unbound as dns backend
automatically selects uclient-fetch or wget as download utility (other tools like curl or aria2c are supported as well)
automatically supports a wide range of router modes, even AP modes are supported
full IPv4 and IPv6 support
supports tld compression (top level domain compression), this feature removes thousands of needless host entries from the block lists and lowers the memory footprint for the dns backends
each block list source will be updated and processed separately
block list source parsing by fast & flexible regex rulesets
overall duplicate removal in separate block lists
additional whitelist for manual overrides, located by default in /etc/adblock/adblock.whitelist
quality checks during block list update to ensure a reliable dns backend service
minimal status & error logging to syslog, enable debug logging to receive more output
procd based init system support (start/stop/restart/reload/suspend/resume)
procd based hotplug support, the adblock start will be triggered by interface triggers
suspend & resume adblock actions temporarily without block list reloading
runtime statistics via ubus service call
query function to quickly identify blocked (sub-)domains, e.g. for whitelisting
optional: automatic block list backup & restore, backups will be (de-)compressed and restored on the fly in case of any runtime error
optional: add new adblock sources on your own via uci config

Prerequisites

openwrt, tested with latest stable release (Chaos Calmer) and with current trunk (Designated Driver)
LEDE project, tested with trunk > r98
a usual setup with an enabled dns backend at minimum - dump AP modes without a working dns backend are not supported
a download utility: full versions (with ssl support) of 'wget', 'uclient-fetch', 'aria2c' or 'curl' are supported - the Chaos Calmer built-in busybox wget is not
- Chaos Calmer: download & install the external 'wget' package
- Designated Driver/Trunk: use built-in 'uclient-fetch' or download & install the external 'wget' package
- for more configuration options see examples below

OpenWrt / LEDE trunk Installation & Usage

install 'adblock' (opkg install adblock) and that's it - the adblock start will be automatically triggered by procd interface triggers
start/stop/restart/reload/suspend/resume the adblock service manually with /etc/init.d/adblock
enable/disable your favored block list sources in /etc/config/adblock - 'adaway', 'disconnect' and 'yoyo' are enabled by default

LuCI adblock companion package

for easy management of the various block list sources and options you can also use a nice & efficient LuCI frontend
install 'luci-app-adblock' (opkg install luci-app-adblock)
the application is located in LuCI under 'Services' menu
Thanks to Hannu Nyman for this great adblock LuCI frontend!

Chaos Calmer installation notes

'adblock' and 'luci-app-adblock' are not available as .ipk packages in the Chaos Calmer download repository
download both packages from a development snapshot package directory:
- for 'adblock' look here
- for 'luci-app-adblock' look here
manually transfer the packages to your routers temp directory (with tools like sshfs or winscp)
install the packages with opkg install <...> as described above

Tweaks

status/runtime statistics: the adblock status and runtime statistics are available via ubus service call (see example below)
debug logging: for script debugging please set the config option 'adb_debug' to '1' and check the runtime output with logread -e "adblock"
storage expansion: to process and store all block list sources at once it might helpful to enlarge your temp directory with a swap partition => see openwrt wiki for further details
add white-/blacklist entries: add domain white- or blacklist entries to always-allow or -deny certain (sub) domains, by default both lists are empty and located in /etc/adblock. Please add one domain per line - ip addresses, wildcards & regex are not allowed (see example below)
backup & restore block lists: enable this feature, to restore automatically the latest compressed backup of your block lists in case of any processing error (e.g. a single block list source is not available during update). Please use an (external) solid partition and not your volatile router temp directory for this
scheduled list updates: for a scheduled call of the adblock service add an appropriate crontab entry (see example below)
restrict/disable procd interface trigger: to restrict the procd interface trigger to a (list of) certain wan interface(s) or to disable it at all, set 'adb_iface' to an existing interface like 'wan' or to a non-existing like 'false'
suspend & resume adblocking: to quickly switch the adblock service 'on' or 'off', simply use /etc/init.d/adblock [suspend|resume]
domain query: to query the active block lists for a specific domain, please run /etc/init.d/adblock query <DOMAIN> (see example below)
divert dns requests: to force dns requests to your local dns resolver add an appropriate firewall rule (see example below)
add new list sources: you could add new block list sources on your own via uci config, all you need is a source url and an awk one-liner (see example below)
disable active dns probing in windows 10: to prevent a yellow exclamation mark on your internet connection icon (which wrongly means connected, but no internet), please change the following registry key/value from "1" to "0" HKLM\SYSTEM\CurrentControlSet\Services\NlaSvc\Parameters\Internet\EnableActiveProbing

Further adblock config options

usually the pre-configured adblock setup works quite well and no manual config overrides are needed, all listed options apply to the 'global' config section:
- adb_enabled => main switch to enable/disable adblock service (default: '1', enabled)
- adb_debug => enable/disable adblock debug output (default: '0', disabled)
- adb_iface => restrict the procd interface trigger to a (list of) certain wan interface(s) or disable it at all (default: not set, disabled)
- adb_fetch => full path to a different download utility, see example below (default: not set, use wget)
- adb_fetchparm => options for the download utility, see example below (default: not set, use wget options)
- adb_tldcomp => enable/disable tld compression (default: '1', enabled)

Examples

change default dns backend to 'unbound':


Adblock detects the presence of an active unbound dns backend and the block lists will be automatically pulled in by unbound.
The adblock script deposits the sorted and filtered block lists in '/var/lib/unbound' where unbound can find them in its jail.
If you use manual configuration for unbound, then just include the following line in your 'server:' clause:

  include: "/var/lib/unbound/adb_list.*"

configuration for different download utilities:


wget (default):
  option adb_fetch="/usr/bin/wget"
  option adb_fetchparm="--no-config --quiet --no-cache --no-cookies --max-redirect=0 --timeout=10 --no-check-certificate -O"

aria2c:
  option adb_fetch '/usr/bin/aria2c'
  option adb_fetchparm '-q --timeout=10 --allow-overwrite=true --auto-file-renaming=false --check-certificate=false -o'

uclient-fetch:
  option adb_fetch '/bin/uclient-fetch'
  option adb_fetchparm '-q --timeout=10 --no-check-certificate -O'

curl:
  option adb_fetch '/usr/bin/curl'
  option adb_fetchparm '-s --connect-timeout 10 --insecure -o'

receive adblock statistics via ubus:


ubus call service list '{"name":"adblock_stats"}'
This will output the active block lists and other runtime information as JSON, e.g.:
{
    "adblock_stats": {
        "instances": {
            "statistics": {
                "running": false,
                "command": [
                    ""
                ],
                "data": {
                    "active_lists": [
                        {
                            "palevo": "14",
                            "blacklist": "144",
                            "winspy": "168",
                            "zeus": "422",
                            "adaway": "408",
                            "rolist": "649",
                            "malwarelist": "1219",
                            "ransomware": "1495",
                            "ruadlist": "1791",
                            "yoyo": "2304",
                            "openphish": "2139",
                            "dshield": "154",
                            "disconnect": "3176",
                            "spam404": "6251",
                            "adguard": "11081",
                            "whocares": "11575",
                            "winhelp": "10574",
                            "malware": "13854",
                            "sysctl": "8539",
                            "securemecca": "9262",
                            "shalla": "25358",
                            "hphosts": "36256"
                        }
                    ],
                    "adblock_version": "2.3.0",
                    "blocked_domains": "146833",
                    "dns_backend": "dnsmasq",
                    "last_rundate": "04.02.2017 21:10:31",
                    "system": "LEDE Reboot SNAPSHOT r3286-c980147527"
                }
            }
        }
    }
}

cronjob for a regular block list update (/etc/crontabs/root):


0 06 * * *    /etc/init.d/adblock start

blacklist entry (/etc/adblock/adblock.blacklist):


ads.example.com

This entry blocks the following (sub)domains:
  http://ads.example.com/foo.gif
  http://server1.ads.example.com/foo.gif
  https://ads.example.com:8000/

This entry does not block:
  http://ads.example.com.ua/foo.gif
  http://example.com/

whitelist entry (/etc/adblock/adblock.whitelist):


here.com

This entry removes the following (sub)domains from the block lists:
  maps.here.com
  here.com

This entry does not remove:
  where.com
  www.adwhere.com

query active block lists for a certain (sub-)domain, e.g. for whitelisting:


/etc/init.d/adblock query example.www.doubleclick.net
::: distinct results for domain 'example.www.doubleclick.net'
 no match
::: distinct results for domain 'www.doubleclick.net'
 adb_list.sysctl      : www.doubleclick.net
::: distinct results for domain 'doubleclick.net'
 adb_list.adaway      : ad-g.doubleclick.net
 adb_list.securemecca : 1168945.fls.doubleclick.net
 adb_list.sysctl      : 1435575.fls.doubleclick.net
 adb_list.whocares    : 3ad.doubleclick.net

The query function checks against the submitted (sub-)domain and recurses automatically to the upper top level domain(s).
For every domain it returns the overall count plus a distinct list of active block lists with the first relevant result.
In the example above whitelist "www.doubleclick.net" to free the submitted domain.

divert dns requests to local dns resolver in /etc/config/firewall:


config redirect
    option name 'Divert DNS'
    option src 'lan'
    option proto 'tcp udp'
    option src_dport '53'
    option dest_port '53'
    option target 'DNAT'

add a new block list source:


1. the easy way ...
example: https://easylist-downloads.adblockplus.org/rolist+easylist.txt
adblock already supports an easylist source, called 'ruadlist'. To add the additional local easylist
as a new source, copy the existing config source 'ruadlist' section and change only
the source name, the url and the description - that's all!

config source 'rolist'
  option enabled '0'
  option adb_src 'https://easylist-downloads.adblockplus.org/rolist+easylist.txt'
  option adb_src_rset '{FS=\"[|^]\"} \$0 ~/^\|\|([A-Za-z0-9_-]+\.){1,}[A-Za-z]+\^$/{print tolower(\$3)}'
  option adb_src_desc 'focus on romanian ad related domains plus generic easylist additions, weekly updates, approx. 600 entries'

2. a bit harder ...
to add a really new source with different domain/host format you have to write a suitable
awk one-liner on your own, so basic awk skills are needed. As a starting point check the already
existing awk strings (adb_src_rset) in adblock config, maybe you need only small changes for your individual list.
Download the desired list and test your new awk string locally with:
  cat new.list | awk 'fs__individual search__search core__result'
  'fs' => field separator (optional)
  'individual search' => individual search part to filter out needless list information
  'search core' => always '([A-Za-z0-9_-]+\.){1,}[A-Za-z]+', this is part of all list sources and should be unchanged
  'result' => always '{print tolower(\$n)}', only the output column 'n' may vary
the output result should be a sequential list with one domain/host per line - nothing more.

If your awk one-liner works quite well, add a new source section in adblock config and test your new source

Support

Please join the adblock discussion in this forum thread or contact me by mail dev@brenken.org

Removal

stop all adblock related services with /etc/init.d/adblock stop
optional: remove the adblock package (opkg remove adblock)

Have fun!
Dirk

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