TODO Improvements

• io_submit to batch up syscalls?
• send(MSG_ZEROCOPY): https://lwn.net/Articles/726917/
• SOCKMAP? https://www.gnu.org/software/tar/manual/html_node/Standard.html

TODO:

• Enable EPOLLET & EPOLLONESHOT?
• Short read/write means no need to try again
• use event.data.ptr to find connection, not look up by fd
• EPOLLRDHUP?
• EPOLLHUP? (don't bother reading from closed connection)
• Keepalive connection
• request timeout
• support headerless, where all headers are already pre-inserted into the tarfile
• verify that archive doesn't have sparse files
• content-type
• FDO

Useful references

• https://youtu.be/8NSzkYSX5nY
• https://youtu.be/36qZYL5RlgY

Memory allocations per request

Full file request

• 4096 bytes request read buffer.
• 40 bytes for 5 output queue entries
  • status200
  • if applicable: keepalive header
  • if applicable: transfer encoding header
  • file-specific headers (namely content-length)
  • contents

Range read

• 4096 bytes request read buffer.
• regex match_results parsing range header
• 48 bytes (should be enough) for range header
• output queue entries (see full request)