Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorFirst time using lwIP
Hello, I´ve started using lwIP this week. I tried the Webserver example and it worked fine (I can access the webpage from my browser =).
Well... I read the code many times and couldn´t understand how it works. I didn´t find any good documentation about it either. I just want to create a simple app server to send and receive messages (from a telnet client, for example). I didn't find any API like "send" and "recv" of Socket's... Do someone have any example that could help me? Until now, my code is just it: main() { alt_avalon_lan91c111_if* dev_list_ptr = (alt_avalon_lan91c111_if*)alt_ethernet_device_list.next; lwip_init(); IP4_ADDR(&ipaddr, 192, 168, 0, 100); IP4_ADDR(&netmask, 255, 255, 255, 0); IP4_ADDR(&gw, 192, 168, 0, 1); netif_add(&netif, &ipaddr, &netmask, &gw, (void*)dev_list_ptr, lan91c111if_init, ip_input); netif_set_default(&netif); pcb = tcp_new(); tcp_bind(pcb, IP_ADDR_ANY, 80); pcb = tcp_listen(pcb); } Then I don't know how to go on (I don´t even know if I´m in the right way...) Can anybody help me? Thanks4 Replies
Altera_ForumHi HoffPistolao,
you should first download this pdf-file: http://www.sics.se/~adam/lwip/doc/lwip.pdf (http://www.sics.se/~adam/lwip/doc/lwip.pdf) that is documentation on the lwip-stack. I tried to modify without reading it to but it really doesn't work. They told on this forum that I first should try to understand it. That's what I did en that way you can really develop something usefull. Good luck..... Cheers, Danny- Altera_Forum
Thanks for the pdf.
I can start the server now, but I still can't send and receive messages. How do I use the tcp_accept anyway? I tried something like pcb = tcp_new(); tcp_bind(pcb, IP_ADDR_ANY, 80); pcb = tcp_listen(pcb); tcp_accept(pcb, ERR_OK); while(1) { printf("\nI will send"); getchar(); tcp_write(pcb, "lalala", sizeof("lalala"), 0); } Well.... then my client can connect, but it won´t receive anything. If I do something like: tcp_accept(pcb, envia); and create the function "envia" like this: static err_t envia(void *arg, struct tcp_pcb *pcb, err_t err) { int i; for(i = 0; i < 5; i++) { printf("\nVou enviar"); getchar(); tcp_write(pcb, "lalala", sizeof("lalala"), 0); } return ERR_OK; } It will send the "lalala" five times when it reaches the "return". But I want to use the tcp_write inside the main How do I do that? Thanks - Altera_Forum
It looks like you're trying to LWIP's "raw" and/or stand alone API. This is a _callback_-based API. You need to, at a bare minimum, read through the raw_api.txt file.
In addition, it makes sense to take a look at the TCP echo server, included with the distribution on this website, and use it as a basis for starting your own application. Once you have it working, you'll have much more luck stripping out what you don't feel you need. Cheers, - slacker - Altera_Forum
Hello,
I read that document and I also have the webserver working here. But it still use that open-read-write-close idea, right? I need to write a code to talk to a client. I mean... I can send messages to the client inside the function called on "tcp_accept", but just that. I can't keep sending (or receiving) messages in main(). How can I do that?
