etherif.c

实现在ARM上的ICP/IP功能的源代码。

#include "true_false.h"
#include "stdlib.h"
#include "typedef.h"
#include "mem_man.h"
#include "rtl8019.h"
#include "netif.h"
#include "etherif.h"
#include "ip.h"
#include "arp.h"
#include "utilities.h"

/* call output to put a packet from IP layer to device. After
	Ip layer selected a device, it use output to send this packet.
	MemHead contain a packet and Netif tell dirver which netif it 
	is. NOTE:MemHead->pStart point to pIPHead
return:
	TRUE: send successfuly.*/
BOOL EtherOutput(struct SMemHead*MemHead,struct SNetIf*NetIf,IP_ADDR DestIP)  
{
	DWORD NextIP;	/* next host to receive the packet in rout */
	struct SEtherHead *pEtherHead;
	struct SMemHead *p;
	
	pEtherHead = (struct SEtherHead   *)(MemHead->pStart - sizeof(struct SEtherHead));
		
	/* if DestIP in this subnet ... */
	if((NetIf->NetMask & NetIf->IPAddr) == (NetIf->NetMask & DestIP))
		NextIP = DestIP;
	else
		NextIP = NetIf->GateWay;

	/* find Ether addr of NextIP */
	if(ARPFind((void*)pEtherHead->DestAddr,NextIP) == FALSE)
	{
		/* send a arp query */
		if((p = ARPQuery(NetIf,NextIP)) != NULL)
		{	
			((struct SEtherDevice   *)(NetIf->Info))->send(
				p->pStart,sizeof(struct SARPPacket) + 
				sizeof(struct SEtherHead));

			MemFree(p);
		}
	}
	else
	{
		/* fill ehter header, DestAddr already filled in ARPFind */
		MemCopy((void*)pEtherHead->ScrAddr,
			(void*)((struct SEtherDevice   *)(NetIf->Info))->Addr,ETHER_ADDR_LEN);

		pEtherHead->type = htons(ETHER_TYPE_IP);	

		/* send the packet. packet lenth is less than MemHead size */
		return ((struct SEtherDevice   *)(NetIf->Info))->send(
			(BYTE *)pEtherHead,(WORD)(MemHead->pEnd - (BYTE   *)pEtherHead));
	}
	return FALSE;
	/* free MemHead when it is acked in tcp model */
}

/* this function is called periodically.Get a packet from specific
device. If there is a packet, call NetIf->Input to do more */
void EtherInput(struct SNetIf * NetIf)  
{
	struct SMemHead   *MemHead;
	struct SEtherHead   *pEtherHead;
	struct SMemHead   *p;

	/* if there is a packet to deal with */
	while((MemHead = ((struct SEtherDevice   *)(NetIf->Info))->recv())
		!= NULL)
	{
		/* Note, pStart point to EtherHead */
		pEtherHead = (struct SEtherHead   *)(MemHead->pStart);
		
		/* which packet type */
		switch(ntohs(pEtherHead->type))
		{
		case ETHER_TYPE_IP:
			/* before pass to IP layer, let MemHead->pStart point
			to IP header */
			#ifdef debug_eth
			Uart_Printf("\nETHERIF: RCV AN IP FRAME...\n");
			#endif
			MemHead->pStart += sizeof(struct SEtherHead);

			/* pass to IP layer for more dealing */
IPInput(MemHead);
			
			break;

		case ETHER_TYPE_ARP:
#ifdef debug_eth
	Uart_Printf( "\ncase ETHER_TYPE_ARP:\n" ) ;	
#endif
			if((p = ARPInput(MemHead,NetIf)) != NULL)
			{
				/* a arp reply need to be send */
				((struct SEtherDevice   *)(NetIf->Info))->send(
					p->pStart,sizeof(struct SARPPacket) 
					+ sizeof(struct SEtherHead));

				MemFree(p);
			}
			/* 'MemHead' is freed in ARPInput() */
			break;
		default:

			/* unknown packet type free */
			MemFree(MemHead);
		}
	}
}
/* ethernet device init */
void EtherDevInit(struct SEtherDevice *pDevice,
BYTE EtherAddr[],
BOOL ( *send)(BYTE *buf,WORD size),
struct SMemHead * (*recv)() )   
{
    MemCopy(pDevice->Addr,EtherAddr,ETHER_ADDR_LEN);
    pDevice->recv=recv ;
    pDevice->send=send ;
}