Described initialization procedure.

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christiaans 2005-11-02 08:08:06 +00:00
parent 7599985a0a
commit 6a17ef925d

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@ -1,6 +1,6 @@
Raw TCP/IP interface for lwIP
Authors: Adam Dunkels, Leon Woestenberg
Authors: Adam Dunkels, Leon Woestenberg, Christiaan Simons
lwIP provides two Application Program's Interfaces (APIs) for programs
to use for communication with the TCP/IP code:
@ -290,3 +290,97 @@ level of complexity of UDP, the interface is significantly simpler.
Specifies a callback function that should be called when a UDP
datagram is received.
--- System initalization
A truly complete and generic sequence for initializing the lwip stack
cannot be given because it depends on the build configuration (lwipopts.h)
and additional initializations for your runtime environment (e.g. timers).
We can give you some idea on how to proceed when using the raw API.
We assume a configuration using a single Ethernet netif and the
UDP and TCP transport layers, IPv4 and the DHCP client.
Call these functions in the order of appearance:
- stats_init()
Clears the structure where runtime statistics are gathered.
- sys_init()
Not of much use since we set the NO_SYS 1 option in lwipopts.h,
to be called for easy configuration changes.
- mem_init()
Initializes the dynamic memory heap defined by MEM_SIZE.
- memp_init()
Initializes the memory pools defined by MEMP_NUM_x.
- pbuf_init()
Initializes the pbuf memory pool defined by PBUF_POOL_SIZE.
- etharp_init()
Initializes the ARP table and queue.
Note: you must call etharp_tmr at a 10 second regular interval
after this initialization.
- ip_init()
Doesn't do much, it should be called to handle future changes.
- udp_init()
Clears the UDP PCB list.
- tcp_init()
Clears the TCP PCB list and clears some internal TCP timers.
Note: you must call tcp_fasttmr() and tcp_slowtmr() at the
predefined regular intervals after this initialization.
- netif_add(struct netif *netif, struct ip_addr *ipaddr,
struct ip_addr *netmask, struct ip_addr *gw,
void *state, err_t (* init)(struct netif *netif),
err_t (* input)(struct pbuf *p, struct netif *netif))
Adds your network interface to the netif_list. Allocate a struct
netif and pass a pointer to this structure as the first argument.
Give pointers to cleared ip_addr structures when using DHCP,
or fill them with sane numbers otherwise. The state pointer may be NULL.
The init function pointer must point to a initialization function for
your ethernet netif interface. The following code illustrates it's use.
err_t netif_if_init(struct netif *netif)
{
u8_t i;
for(i = 0; i < 6; i++) netif->hwaddr[i] = some_eth_addr[i];
init_my_eth_device();
return ERR_OK;
}
The input function pointer must point to the lwip ip_input().
- netif_set_default(struct netif *netif)
Registers the default network interface.
- netif_set_up(struct netif *netif)
When the netif is fully configured this function must be called.
- dhcp_start(struct netif *netif)
Creates a new DHCP client for this interface on the first call.
Note: you must call dhcp_fine_tmr() and dhcp_coarse_tmr() at
the predefined regular intervals after starting the client.
You can peek in the netif->dhcp struct for the actual DHCP status.