arp.c

Boot code for ADM5120 with serial console for Edimax router.

/*****************************************************************************
;
;   (C) Unpublished Work of ADMtek Incorporated.  All Rights Reserved.
;
;       THIS WORK IS AN UNPUBLISHED WORK AND CONTAINS CONFIDENTIAL,
;       PROPRIETARY AND TRADESECRET INFORMATION OF ADMTEK INCORPORATED.
;       ACCESS TO THIS WORK IS RESTRICTED TO (I) ADMTEK EMPLOYEES WHO HAVE A
;       NEED TO KNOW TO PERFORM TASKS WITHIN THE SCOPE OF THEIR ASSIGNMENTS
;       AND (II) ENTITIES OTHER THAN ADMTEK WHO HAVE ENTERED INTO APPROPRIATE
;       LICENSE AGREEMENTS.  NO PART OF THIS WORK MAY BE USED, PRACTICED,
;       PERFORMED, COPIED, DISTRIBUTED, REVISED, MODIFIED, TRANSLATED,
;       ABBRIDGED, CONDENSED, EXPANDED, COLLECTED, COMPILED, LINKED, RECAST,
;       TRANSFORMED OR ADAPTED WITHOUT THE PRIOR WRITTEN CONSENT OF ADMTEK.
;       ANY USE OR EXPLOITATION OF THIS WORK WITHOUT AUTHORIZATION COULD
;       SUBJECT THE PERPERTRATOR TO CRIMINAL AND CIVIL LIABILITY.
;
;------------------------------------------------------------------------------
;
;    Project : Common Plateform
;    Creator : 
;    File    : arp.c
;    Abstract: defines the specific items that loader nedded.
;
;Modification History:
;       By              Date     Ver.   Modification Description
;       --------------- -------- -----  --------------------------------------
;
;*****************************************************************************/
#include <ctype.h>
#include <skbuff.h>
#include <eth.h>
#include <arp.h>

#define ARP_CACHE_SIZE	16

typedef struct arp_entry {
	unsigned char ar_ha[ETH_ALEN];
	unsigned long ar_ip;
} arp_entry;

static arp_entry arp_entrys;
static arp_entry arp_cache[ARP_CACHE_SIZE];
static int arp_chche_cur = 0;

int arp_init(void)
{
	int eth_num;
	UINT32 tftpip;
	UINT8 eth_addr[6];

	memset(&arp_entrys, 0, sizeof(arp_entry));
	memset(arp_cache, 0, sizeof(arp_entry) * ARP_CACHE_SIZE);
	if ((bsp_GetMacBase(eth_addr, &eth_num) == 0) && (bsp_GetTftpIp(&tftpip) == 0))
		arp_add_entry(eth_addr, tftpip);
	return 0;
}

int arp_add_entry(unsigned char *ha, unsigned long ip)
{
	memcpy(arp_entrys.ar_ha, ha, ETH_ALEN);
	arp_entrys.ar_ip = htonl(ip);
	return 0;
}

int arp_add_cache(unsigned char *ha, unsigned long ip)
{
	int i;

	for (i = 0; i < ARP_CACHE_SIZE; i++) {
		if (ip == arp_cache[i].ar_ip)
			break;
	}

	if (i == ARP_CACHE_SIZE) {
		i = arp_chche_cur;
		arp_chche_cur = (arp_chche_cur + 1) % ARP_CACHE_SIZE;
	}

	memcpy(arp_cache[i].ar_ha, ha, ETH_ALEN);
	arp_cache[i].ar_ip = ip;

	return 0;
}

int arp_send_req(unsigned long ip)
{
	struct sk_buff skb;
	struct arphdr *arp_req;
	unsigned char broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

	skb_headerinit(&skb);
	eth_skb_reserve(&skb);
	arp_req = (struct arphdr *) skb_put(&skb, sizeof(struct arphdr));

	arp_req->ar_hrd = htons(ARPHRD_ETHER);
	arp_req->ar_pro = htons(ETH_P_IP);
	arp_req->ar_hln = 0x06;
	arp_req->ar_pln = 0x04;
	arp_req->ar_op = htons(ARPOP_REQUEST);
	memcpy(arp_req->ar_sha, arp_entrys.ar_ha, ETH_ALEN);
	arp_req->ar_sip = arp_entrys.ar_ip;
	memset(arp_req->ar_tha, 0x00, ETH_ALEN);
	arp_req->ar_tip = htonl(ip);

	eth_send(&skb, broadcast, ETH_P_ARP);

	return 0;
}

int arp_send_rsp(struct arphdr *arp_hdr)
{
	struct sk_buff skb;
	struct arphdr *arp_rsp;

	skb_headerinit(&skb);
	eth_skb_reserve(&skb);
	arp_rsp = (struct arphdr *) skb_put(&skb, sizeof(struct arphdr));

	arp_rsp->ar_hrd = htons(ARPHRD_ETHER);
	arp_rsp->ar_pro = htons(ETH_P_IP);
	arp_rsp->ar_hln = 0x06;
	arp_rsp->ar_pln = 0x04;
	arp_rsp->ar_op = htons(ARPOP_REPLY);
	memcpy(arp_rsp->ar_sha, arp_entrys.ar_ha, ETH_ALEN);
	arp_rsp->ar_sip = arp_hdr->ar_tip;
	memcpy(arp_rsp->ar_tha, arp_hdr->ar_sha, ETH_ALEN);
	arp_rsp->ar_tip = arp_hdr->ar_sip;

	eth_send(&skb, arp_hdr->ar_sha, ETH_P_ARP);

	return 0;
}

int arp_get_eth_addr(unsigned long ip, unsigned char *ha)
{
	int i;

	for (i = 0; i < ARP_CACHE_SIZE; i++) {
		if (htonl(ip) == arp_cache[i].ar_ip) {
			memcpy(ha, arp_cache[i].ar_ha, ETH_ALEN);
			break;
		}
	}

	if (i == ARP_CACHE_SIZE) {
		arp_send_req(ip);
		return -1;
	}

	return 0;
}

int arp_rcv_packet(struct sk_buff *skb)
{
	struct arphdr *arp_hdr = (struct arphdr *) (skb->data);

	if (arp_hdr->ar_tip != arp_entrys.ar_ip)
		return 0;

	if (arp_hdr->ar_op == htons(ARPOP_REQUEST))
		arp_send_rsp(arp_hdr);
	arp_add_cache(arp_hdr->ar_sha, arp_hdr->ar_sip);

	return 0;
}