added script to update ads lists, old script relocated.

There's a new way of blocking lists of domains:
https://github.com/evilsocket/opensnitch/wiki/block-lists

However the update of the lists is not implemented yet. You can use
this or other simple script to download and update the lists (in hosts
format).

utils/scripts/ads/update_adlists.sh

@@ -0,0 +1,91 @@
+#!/bin/bash
+# opensnitch - 2021
+#
+# https://github.com/evilsocket/opensnitch/wiki/block-lists
+# 
+# Add the script to a regular user's crontab:
+# $ crontab -e
+# 0 11,17,23 * * * /home/user/scripts/update_adlists.sh
+
+# https://pgl.yoyo.org/adservers/serverlist.php?hostformat=hosts&showintro=0&mimetype=plaintext
+# https://hostfiles.frogeye.fr/multiparty-trackers-hosts.txt
+# https://hostfiles.frogeye.fr/firstparty-trackers-hosts.txt
+# https://adaway.org/hosts.txt
+# https://www.github.developerdan.com/hosts/lists/tracking-aggressive-extended.txt
+# https://raw.githubusercontent.com/Kees1958/W3C_annual_most_used_survey_blocklist/master/TOP_EU_US_Ads_Trackers_HOST
+# https://curben.gitlab.io/malware-filter/urlhaus-filter-hosts.txt
+
+# Use any directory you want to save the lists.
+# If you use /etc/opensnitchd, give write permissions to blocklists/* for your user (chown -R /etc/opensnitchd/blocklists/).
+# or use a directory from your user's home.
+adsDir="/etc/opensnitchd/blocklists/domains/"
+
+# If you add new urls, remember to add the corresponding filename where it'll be save on disk.
+adsList=(
+    "https://curben.gitlab.io/malware-filter/urlhaus-filter-hosts.txt"
+    "https://raw.githubusercontent.com/Kees1958/W3C_annual_most_used_survey_blocklist/master/TOP_EU_US_Ads_Trackers_HOST"
+    "https://hostfiles.frogeye.fr/multiparty-trackers-hosts.txt"
+    "https://hostfiles.frogeye.fr/firstparty-trackers-hosts.txt"
+    "https://www.github.developerdan.com/hosts/lists/tracking-aggressive-extended.txt"
+    "https://adaway.org/hosts.txt"
+    "https://pgl.yoyo.org/adservers/serverlist.php?hostformat=hosts&showintro=0&mimetype=plaintex")
+adsListNames=(
+    "urlhaus-filter-hosts.txt"
+    "top_eu_us_ads_trackers.txt"
+    "multiparty-trackers-hosts.txt"
+    "firstparty-trackers-hosts.txt"
+    "tracking-aggressive-extended.txt"
+    "adaway-hosts.txt"
+    "yoyo-adservers.txt")
+
+function download_cname_trackers
+{
+    remoteSize=$(curl --silent -I https://raw.githubusercontent.com/AdguardTeam/AdguardFilters/master/SpywareFilter/sections/cname_trackers.txt | awk '/content-length:/ {print $2}'|tr -d '\r')
+    localSize=$(stat -c %s $adsDir/cname_trackers.txt)
+    if [ ! -z $remoteSize ]; then
+        if [ "$remoteSize" != "$localSize" ]; then
+            > /tmp/.cname_temp
+            cname_trackers=$(curl --silent https://raw.githubusercontent.com/AdguardTeam/AdguardFilters/master/SpywareFilter/sections/cname_trackers.txt | awk '/^!#include/ { print $2 }')
+            for tracker in $cname_trackers
+            do
+                curl --silent $tracker | grep "^||" | sed 's/^||\(.*\)^/0.0.0.0 \1/' >> /tmp/.cname_temp
+            done
+            mv /tmp/.cname_temp $adsDir/cname_trackers.txt
+        else
+            echo "[-] cname trackers not updated yet"
+        fi
+    fi
+}
+
+function download_ads_list
+{
+    reload=0
+    for idx in ${!adsList[@]}
+    do
+        echo "[+] Checking list ${adsList[$idx]}, ${adsListNames[$idx]}"
+        remoteSize=$(curl --silent -I ${adsList[$idx]}|awk '/content-length:/ {print $2}'|tr -d '\r')
+        localSize=$(stat -c %s $adsDir/${adsListNames[$idx]})
+
+        if [ ! -z $remoteSize ]; then
+            if [ "$remoteSize" != "$localSize" ]; then
+                echo "[+] downloading new ads list... ${adsList[$idx]}, $remoteSize, $localSize"
+                curl --silent "${adsList[$idx]}" -o $adsDir/${adsListNames[$idx]}
+                reload=1
+            else
+                echo "[-] ads list not updated yet:  $remoteSize, $localSize - ${adsList[$idx]}"
+            fi
+        else
+            echo "[!] No content-length header found: ${adsList[$idx]}"
+        fi
+    done
+}
+
+
+if [ ! -d $adsDir ]; then
+    mkdir -p $adsDir
+fi
+
+cd $adsDir
+
+download_ads_list
+download_cname_trackers