Can boost::asio::async_read_until detect an endless stream

Question

I am using boost::asio::async_read_until to read a message from a socket, using a newline as a delimiter.

eg boost::asio::async_read_until(socket, buffer, "\\n", .....)

Everything is hunkey dorey and works fine.

Is there an alternative way to use this function, or a similar one, that can detect an endless sequence of characters that do not have a newline constant in them.

eg a malicious user might fire a continuous sequence of ZEROS at my server

socat /dev/zero TCP4:localhost:55555

I can't be the first person in history to have come across this problem

Answer 1

You can use version 4 of the 4 overloads:

http://www.boost.org/doc/libs/1_62_0/doc/html/boost_asio/reference/async_read_until/overload4.html

In your function object, which would normally be an interface to a state machine, you can count characters, detect illegal data streams or any other means necessary.

It's probably worth mentioning that if your application is running in a hostile environment (ie internet-facing) then you will probably want to use async_read_some to feed your state machine and will want a timer to catch and kill connections that sit and consume resources.