net.c

基于Freescale的MX21处理器的bootloader程序

/*
 *	Copied from Linux Monitor (LiMon) - Networking.
 *
 *	Copyright 1994 - 2000 Neil Russell.
 *	(See License)
 *	Copyright 2000 Roland Borde
 *	Copyright 2000 Paolo Scaffardi
 *	Copyright 2000, 2001 Wolfgang Denk
 * 
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <[e-mail]>
 */

/*
 * General Desription:
 *
 * The user interface supports commands for BOOTP, RARP, and TFTP.
 * Also, we support ARP internally. Depending on available data,
 * these interact as follows:
 *
 * BOOTP:
 *
 *	Prerequisites:	- own ethernet address
 *	We want:	- own IP address
 *			- TFTP server IP address
 *			- name of bootfile
 *	Next step:	ARP
 *
 * RARP:
 *
 *	Prerequisites:	- own ethernet address
 *	We want:	- own IP address
 *			- TFTP server IP address
 *	Next step:	ARP
 *
 * ARP:
 *
 *	Prerequisites:	- own ethernet address
 *			- own IP address
 *			- TFTP server IP address
 *	We want:	- TFTP server ethernet address
 *	Next step:	TFTP
 *
 * DHCP:
 *
 *     Prerequisites:   - own ethernet address
 *     We want:         - IP, Netmask, ServerIP, Gateway IP
 *                      - bootfilename, lease time
 *     Next step:       - TFTP
 *
 * TFTP:
 *
 *	Prerequisites:	- own ethernet address
 *			- own IP address
 *			- TFTP server IP address
 *			- TFTP server ethernet address
 *			- name of bootfile (if unknown, we use a default name
 *			  derived from our own IP address)
 *	We want:	- load the boot file
 *	Next step:	none
 */

#include <stdio.h>
#include <string.h>
#include "net.h"
#include "console.h"

char		NetOurEther[6];		/* Our ethernet address			*/
IPaddr_t	NetOurIP;		/* Our IP addr (0 = unknown)		*/
char		NetBcastAddr[6] =	/* Ethernet bcast address		*/
			{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

char		NetServerEther[6];
IPaddr_t	NetServerIP;		/* Our IP addr (0 = unknown)		*/
unsigned short NetServerPort;

volatile uchar *NetRxPkt;		/* Current receive packet		*/
int		NetRxPktLen;		/* Current rx packet length		*/
unsigned	NetIPID;		/* IP packet ID				*/
int		NetState;		/* Network loop state			*/

//void		NetPrintEther(volatile uchar * addr);


void NetSendPacket(volatile char * pkt, int len)
{
	eth_send(pkt, len);
}

void NetReceive(volatile char * pkt, int len)
{
	Ethernet_t *et;
	IP_t	*ip;
	ARP_t	*arp;
	int	x;

//	NetRxPkt = pkt;
//	NetRxPktLen = len;
	et = (Ethernet_t *)pkt;
	x = SWAP16(et->et_protlen);
	ip = (IP_t *)(pkt + ETHER_HDR_SIZE);
	len -= ETHER_HDR_SIZE;

	if (x == PROT_ARP) {
		arp = (ARP_t *)ip;
		if (len < ARP_HDR_SIZE) {
			printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
			return;
		}
		if (SWAP16(arp->ar_hrd) != ARP_ETHER) {
			return;
		}
		if (SWAP16(arp->ar_pro) != PROT_IP) {
			return;
		}
		if (arp->ar_hln != 6) {
			return;
		}
		if (arp->ar_pln != 4) {
			return;
		}

		if (NetOurIP == 0) {
			return;
		}
		
		{
			IPaddr_t ip = NetReadIP((char*)&arp->ar_data[16]);
			if (ip != NetOurIP) {
				return;
			}
		}

		switch (SWAP16(arp->ar_op)) {
		case ARPOP_REQUEST:		/* reply with our Ether address	*/
			NetSetEther((char *)et, (char *)(et->et_src), PROT_ARP);
			arp->ar_op = SWAP16(ARPOP_REPLY);
			NetCopyEther(NetServerEther, &arp->ar_data[0]);
			NetServerIP = NetReadIP(&arp->ar_data[6]);
			NetCopyEther(&arp->ar_data[0],  NetOurEther);
			NetWriteIP(  &arp->ar_data[6],  NetOurIP);
			NetCopyEther(&arp->ar_data[10], NetServerEther);
			NetWriteIP(  &arp->ar_data[16], NetServerIP);
			NetSendPacket((char *)et,((char *)arp-pkt)+ARP_HDR_SIZE);
			return;
		case ARPOP_REPLY:		/* set TFTP server eth addr	*/
#if 0
			/* check if target ether is ours */
			if ( memcmp(NetOurEther, &(arp->ar_data[10]), 6) != 0 )
			{
				return;
			}			
			NetCopyEther(NetServerEther, &arp->ar_data[0]);
			printf("eth addr: ");
			NetPrintEther(NetServerEther);
			(*packetHandler)(0,0,0,0);	/* start TFTP */
			return;
#endif
		default:
			return;
		}
	}
	else if (x == PROT_IP){
		if ((len < IP_HDR_SIZE)||(len < SWAP16(ip->ip_len))){
			return;
		}

		len = SWAP16(ip->ip_len);
		if ((ip->ip_hl_v & 0xf0) != 0x40) {
			return;
		}
		if (ip->ip_off & SWAP16c(0x1fff)) {
			printf("can't deal with fragments\n");
			return;
		}
		if (!NetCksumOk((char *)ip, IP_HDR_SIZE_NO_UDP / 2)) {
			printf("checksum bad\n");
			return;
		}
		if (NetOurIP) {
		    IPaddr_t ipaddr = NetReadIP((char*)&ip->ip_dst);
		    if (ipaddr != NetOurIP && ipaddr != 0xFFFFFFFF){
				return;
			}
		}

		if (ip->ip_p == IPPROTO_ICMP) {
			icmp_echo_reply(pkt);
			return;
		} 
		else if (ip->ip_p == IPPROTO_UDP) {	/* Only UDP packets */
			unsigned short port = SWAP16(ip->udp_dst);
			if (port == COMMAND_UDP_PORT){
				NetCopyEther(NetServerEther, (char *)(et->et_src));
				NetServerIP = NetReadIP((char*)&ip->ip_src);
				command_input((char *)ip +IP_HDR_SIZE, (int)(SWAP16(ip->udp_len) - 8));
			}
			else if (port == SERVER_TFTP_PORT){ 
				NetCopyEther(NetServerEther, (char *)(et->et_src));
				NetServerIP = NetReadIP((char*)&ip->ip_src);
				NetServerPort = SWAP16(ip->udp_src);
				tftp_handle((char *)ip +IP_HDR_SIZE, (int)(SWAP16(ip->udp_len) - 8));
			}
			else if (port == LOCAL_TFTP_PORT){
				tftp_handle((char *)ip +IP_HDR_SIZE, (int)(SWAP16(ip->udp_len) - 8));
			}
		}
	}
}

int NetCksumOk(char * ptr, int len)
{
	return !((NetCksum(ptr, len) + 1) & 0xfffe);
}


unsigned NetCksum(char * ptr, int len)
{
	unsigned long	xsum;
	unsigned short *p16 = (unsigned short *)ptr;

	xsum = 0;
	while (len-- > 0){
//		xsum += (*((unsigned short *)ptr)++);
		xsum += (*p16++);
	}
	xsum = (xsum & 0xffff) + (xsum >> 16);
	xsum = (xsum & 0xffff) + (xsum >> 16);
	return (xsum & 0xffff);
}