Re: ALPN support for GnuTLS connections

[Robert Pluim]

>>>>> On Sun, 29 Sep 2024 10:23:17 +0200, Eric Marsden 
>>>>> <eric.marsden@risk-engineering.org> said:

    Eric> Hello,
    Eric> The GnuTLS support in Emacs does not seem to support the TLS extension
    Eric> Application Layer Protocol Negotiation (ALPN). ALPN is no longer just 
useful for
    Eric> faster TLS handshakes (in HTTP/2, for example); it is mandatory in 
certain uses
    Eric> of TLS.

    Eric> The GnuTLS library does support ALPN (since 2013, it seems). My 
understanding is
    Eric> that definitions for the two functions described here would need to 
be added to
    Eric> gnutls.c:

    Eric>   
https://www.gnutls.org/manual/html_node/Application-Layer-Protocol-Negotiation-_0028ALPN_0029.html

Why would we need the 'get' API? Did you want to be able to set the
GNUTLS_ALPN_MANDATORY flag and fail the connection?

For the 'set' I guess we could add a keyword parameter to
`gnutls-negotiate' and its callers, and pass that down to
`gnutls-boot-parameters'.

Robert
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