Musings /Scratch Pad

Scratch pad of design ideas and considerations (needs pruning!)

Misc

  • ⬜ Python ASGI

  • ⬜ Use ecb.h?

  • ⬜ Timed-idle watchers — do stuff at least-so often, if not sooner.

  • ⬜ Dynamic loader for pluggable protocols

  • ⬜ add support for edge-triggered IO (i.e. keep recv’ing until block)?

  • ⬜ Move “server” code - socket(), bind(), etc - into optional server

    functionality. i.e. The library should just provide the IO, for the most part.

  • ⬜ where appropriate utilize feature test macros

Network IO

Polling

  • [x] libev (current)

  • [ ] libapr_poll_t (why?)

  • [ ] nanomsg (why?)

SIGPIPE

  • Globally (signal/sigaction):

    • use signal/sigaction

    • most ubiquitious/easiest

    • least friendly to user code

    • possibly slowest?

  • Thread-wide (pthread_sigmask)

  • At the socket level, POSIX-style (fcntl w/ F_GETNOSIGPIPE/F_SETNOSIGPIPE)

  • At the socket level, BSD-style (setsockopt w/ SO_NOSIGPIPE)

  • At the socket level, SysV-style (no possible via ioctl???)

  • At read/write time (MSG_NOSIGNAL)

    • requires send/recv/sendmsg/recvmsg over write/read/writev/readv

    • not portable?

Notes

  • on Darwin F_SETNOSIGPIPE invokes setsockopt w/ SO_NOSIGPIPE under the covers

  • the file-level O_NONBLOCK flag is used by the kernel to set MSG_DONTWAIT at

    send/recv time!! (see net/socket.c)

  • the FIONBIO ioctl call results in O_NONBLOCK fd-level flag being set

    (see fs/ioctl.c)

  • Mac OS X does have MSG_DONTWAIT, etc. It’s only for DARWIN or Non-POSIX

    sources.

  • Also, look into xnu and linux sources for other goodies such as:

    • MSG_NBIO

    • FNONBLOCK

    • O_NDELAY

    • etc

  • All relevant non-blocking flags, to date:

    • FIONBIO

    • FNONBLOCK

    • MSG_NBIO

    • MSG_DONTWAIT

    • O_NDELAY

    • O_NONBLOCK

  • Sending files:

    • Use sendfile, where available

    • Use mmqp + write, otherwise

Flow control

  • TCP_NODELAY for urgent packets (when/why?)

  • TCP_CORK for manual packet coalescing (when/why?)

Performance

  • Use computed goto’s instead of switch statements?

  • NO: Consider page locking to prevent the most common page faults (that’s super

    rude, though…)

  • NO: Consider interacting with the scheduler via sched.h

Protocols

  • Which pre-standard versions of websockets are supported?

    • ❌ hybi-10

    • ❌ hybi-7

    • ❌ hybi-00

    • ❌ hixie-76

    • ❌ hixie-75

  • ⬜ Support HTTP/2.0

  • ⬜ (?) Support QUIC