support overlay abstract-dgram-listen & unix-dgram-listen

[wjtxyz]

listen for SOCK_DGRAM Unix domain socket

[vi]

There is already some support using unix-dgram: and abstract-dgram:. You specify two addresses, one should exist, the other should not exist.

Example:

A$ socat  - unix-sendto:/tmp/send.sock,bind=/tmp/receive.sock

B$ websocat -b unix-dgram:/tmp/send.sock:/tmp/receive.sock ws://ws.vi-server.org/mirror

A$
123
123
ABCDE
ABCDE

This mode is inconvenient and was just added for completeness.
What are advantages compared to seqpacket: / seqpacket-listen:?

[wjtxyz]

There is already some support using unix-dgram: and abstract-dgram:. You specify two addresses, one should exist, the other should not exist.

Example:

A$ socat  - unix-sendto:/tmp/send.sock,bind=/tmp/receive.sock

B$ websocat -b unix-dgram:/tmp/send.sock:/tmp/receive.sock ws://ws.vi-server.org/mirror

A$
123
123
ABCDE
ABCDE

This mode is inconvenient and was just added for completeness. What are advantages compared to seqpacket: / seqpacket-listen:?

i wonder if this is a bug

websocat version: 1.13.0

linux version ok:

# ./websocat.aarch64-unknown-linux-musl -b - unix-dgram:/tmp/unix.sock:/tmp/unix.sock 

# ./websocat.aarch64-unknown-linux-musl -b unix-dgram:/tmp/unix2.sock:/tmp/unix2.sock -

android version fail:

#  ./websocat.aarch64-linux-android -b - unix-dgram:/tmp/android.sock:/tmp/android.sock 
websocat: No such file or directory (os error 2)
websocat: error running

# ./websocat.aarch64-linux-android -b unix-dgram:/tmp/android.sock:/tmp/android.sock -
websocat: No such file or directory (os error 2)
websocat: error running