Multipart mime 3487 v21

[catenacyber]

Link to redmine ticket:
https://redmine.openinfosecfoundation.org/issues/3487

Describe changes:

• convert HTTP to use new rust mime parser
• convert SMTP to use new rust mime parser

Follows #9437 with fix for rust panic (copying slices must have the exact same size) + removing some dead code cf #9419

@jasonish any ideas on how to get a better feedback that pub rs_mime_find_header_token was no longer used by the C side and should be removed as dead code ?

SV_BRANCH=pr/1371

SV tests from unit tests in OISF/suricata-verify#1371

Draft :

• I think mime: process chunk as soon as possible #9435 should get merged first (and QA rebased over it)

[jasonish]

@jasonish any ideas on how to get a better feedback that pub rs_mime_find_header_token was no longer used by the C side and should be removed as dead code ?

Not really. The Rust code is just compiled into a library with externally addressable functions so I don't think we'll get a compiler to tell us.

[jasonish]

Do you have scripts already for finding unused C code?

nm target/release/libsuricata_rust.a |awk '$2 == "T" && $3 !~ /^_/ { print $3 }'

will get you all externally linkable C functions from the Rust code. There are a few in there for other libraries like Brotli

[catenacyber]

Replaced by #9447

[catenacyber]

@jasonish any ideas on how to get a better feedback that pub rs_mime_find_header_token was no longer used by the C side and should be removed as dead code ?

Not really. The Rust code is just compiled into a library with externally addressable functions so I don't think we'll get a compiler to tell us.

Can a compiler/other tool tell us all the "externally addressable functions" from rust ? and check if they are used from C ?

[jasonish]

Can a compiler/other tool tell us all the "externally addressable functions" from rust ? and check if they are used from C ?

I quick search tells me no. The compiler links looks up functions it needs, it doesn't really see functions it doesn't need. You can remove Rust from this question. As the .a library is the same as any other static C library, so all other tools like nm will work.

[catenacyber]

I was not thinking about nm but some rust-analyzer tool ;-) (if it exists)

[jasonish]

I was not thinking about nm but some rust-analyzer tool ;-) (if it exists)

No, this is outside the scope of Rust and back in C land.