Re: [lwip-devel] [PATCH] tcpip clean shutdown

[address@hidden]

Ross Philipson wrote:
> This patch allows the tcpip processing thread to be shutdown cleanly 
> by posting a shutdown message to its queue.

I hate to disappoint people, but you aren't the first that we turned 
down on this: there were some attempts in the past (on this mailing list 
and in the patches section on savannah) to implement graceful shutdown 
for the stack. However, all of them (including yours) had the downside 
that they
a) added code for people that don't need it and
b) weren't complete in that really all resources are freed (and all 
threads terminated!)

I.e. in your code, you only stop the tcpip_thread, but this is far from 
what you have to do to shut down the stack. You would have to unblock 
all application threads blocking on semaphores for socket/netconn or 
tcpip_callback and preven adding new messages to the queue, you would 
have to free memory allocated by the various protocols, and so on.

Since lwIP is a stack designed for embedded systems that keep the stack 
running while they are turned on, there has been (aside from a few 
people including you) not much need for a graceful shutdown, which is 
why we want to avoid the effort of starting with it.

Simon