Upgrade embedded dnsmasq to v2.80

[DL6ER]

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Official changelog:

• Add support for RFC 4039 DHCP rapid commit. Thanks to Ashram Method for the initial patch and motivation.
• Alter the default for dnssec-check-unsigned. Versions of dnsmasq prior to 2.80 defaulted to not checking unsigned replies, and used --dnssec-check-unsigned to switch this on. Such configurations will continue to work as before, but those which used the default of no checking will need to be altered to explicitly select no checking. The new default is because switching off checking for unsigned replies is inherently dangerous. Not only does it open the possiblity of forged replies, but it allows everything to appear to be working even when the upstream namesevers do not support DNSSEC, and in this case no DNSSEC validation at all is occuring.
• Fix DHCP broken-ness when --no-ping AND --dhcp-sequential-ip are set. Thanks to Daniel Miess for help with this.
• Add a facilty to store DNS packets sent/recieved in a pcap-format file for later debugging. The file location is given by the --dumpfile - option, and a bitmap controlling which packets should be dumped is given by the --dumpmask option.
• Handle the case of both standard and constructed dhcp-ranges on the same interface better. We don't now construct a dhcp-range if there's - already one specified. This allows the specified interface to have different parameters and avoids advertising the same prefix twice. Thanks - to Luis Marsano for spotting this case.
• Allow zone transfer in authoritative mode if auth-peer is specified, even if auth-sec-servers is not. Thanks to Raphael Halimi for the suggestion.
• Fix bug which sometimes caused dnsmasq to wrongly return answers without DNSSEC RRs to queries with the do-bit set, but only when DNSSEC - validation was not enabled. Thanks to Petr Menšík for spotting this.
• Fix missing fatal errors with some malformed options (server, local, address, rebind-domain-ok, ipset, alias). Thanks to Eugene Lozovoy for - spotting the problem.
• Fix crash on startup with a --synth-domain which has no prefix. Introduced in 2.79. Thanks to Andreas Engel for the bug report.
• Fix missing EDNS0 section in some replies generated by local DNS configuration which confused systemd-resolvd. Thanks to Steve Dodd for characterising the problem.
• Add --dhcp-name-match config option.
• Add --caa-record config option.
• Implement --address=/example.com/# as (more efficient) syntactic sugar for --address=/example.com/0.0.0.0 and --address=/example.com/:: - Returning null addresses is a useful technique for ad-blocking. Thanks to Peter Russell for the suggestion.
• Change anti cache-snooping behaviour with queries with the recursion-desired bit unset. Instead to returning SERVFAIL, we now always - forward, and never answer from the cache. This allows "dig +trace" command to work. (fixes Can't dig +trace #383)
• Include in the example config file a formulation which stops DHCP clients from claiming the DNS name "wpad". This is a fix for the CERT Vulnerability VU#598349.

Note: This PR is Work-In-Progress and only meant for testing. As it implements a still rather fresh release of dnsmasq, it should not be merged to development until Pi-hole v4.1 has been released. Consider this branch as experimental as there is a certain likeliness that more internals of pihole-FTL may need to be adapted due to changes deeper inside the dnsmasq code.

The PR statistics are +1,460 -283 when ignoring whitespace changes.

This template was created based on the work of udemy-dl.

[DL6ER]

Ready to be merged into development. The release candidate (release/4.1) to be merged to master has already been branched out from development.

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-v4-2-available-with-shared-memory-new-blocking-modes-and-more/16763/1