Hi,
1. There are other timers, but you might not need them (dhcp, arp,
autoip, dns, ip_reassembly). Other than that, you are right.
2. Yes, that's correct.
3. The tcp timer is only running when a tcp pcb is registered. This gets
triggered from the function tcp_timer_needed() in tcpip.c. This is a
rather unclean part of the code, since the prototype resides in tcp.h
and is only declared #if NO_SYS == 0.
4. That should be enough. You seem to already know that you mustn't use
an lwip socket from 2 threads simultaneously... :-) (I should note that
I have never tried it, but if you make sure there are not two (or more)
threads accessing the socket's data structures (or mboxes) at a time,
you should be fine.)
Simon
Thomas Taranowski schrieb:
the tcpip_init function starts up all the required timers (which
happens in tcpip_thread startup). You should not be starting them
'manually'. The timeout handlers usually have a call to sys_timeout
that set's itself as the timeout handler, which essentially sets up a
periodic timer.
On Jan 14, 2008 12:18 AM, Muhamad Ikhwan Ismail
<[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:
Hi,
I got some qs on timer functions on lwip, read some thread on it
previously but it doesnt really answer my qs.
I ll try to generalize this so that any future user can use this
thread for the same problem.
Im using lwip 1.2 porting it on a SMX OS on PowerPC MPC852T. Just
wanna make sure I am right before i run some multithreading test.
1. The are 2 timers for the whole stack, which are the arptimer
and the tcp timer am I right ?
2. The arptimer is initialized in ethernetif_init through this
piece of code :
sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
which then will be assign a struct timeout to the tcpip thread's
timeout (since I call it from the tcpip thread initialization)
linked list and will be checked and updated each time I wait on
semaphore or fetch a message. Hence I dont have to call the
arptimer().
Am I correct so far ?
3. My biggest problem is the tcp_timer. It is called by the
tcpip_tcp_timer by tcpip API. But no other function calls the
tcpip_tcp_timer
hence I guess I need to call it myself ? If I do have to call it
myself, I guess there are 2 ways. One is I call it before I wait
for semaphore after tcpip_thread finishes the job
it got with the message it fetched. Or call another thread to call
tcpip_tcp_timer which is literally bad cause the stack itself is
not multithreading safe, isnt it?
If anyone has done something like this and has tips where I can
use the timer safely, I'd appreciate any tips.
4.I am writing a telnet server program which have 2 task, both
using the same socket for transmit and receive. This is possible
if i do a critical section protection each time
the socket does receive or send, preventing simultaneous access on
the socket, am I right ?
I am thankful for any answers you could provide me.
Greetings,
Ikhwan
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