ping.c

/*
 *	Copied from Linux Monitor (LiMon) - Networking.
 *
 *	Copyright 1994 - 2000 Neil Russell.
 *	(See License)
 *	Copyright 2000 Roland Borde
 *	Copyright 2000 Paolo Scaffardi
 *	Copyright 2000-2002 Wolfgang Denk, wd@denx.de
 */

#include "ping.h"
#include "arp.h"

static ushort PingSeqNo;

/* The ip address to ping */
IPaddr_t NetPingIP;

static int ping_send(void)
{
	static uchar mac[6];
	struct ip_udp_hdr *ip;
	ushort *s;
	uchar *pkt;

	/* XXX always send arp request */

	memcpy(mac, NetEtherNullAddr, 6);

	debug("sending ARP for %pI4\n", &NetPingIP);

	NetArpWaitPacketIP = NetPingIP;
	NetArpWaitPacketMAC = mac;

	pkt = NetArpWaitTxPacket;
	pkt += NetSetEther(pkt, mac, PROT_IP);

	ip = (struct ip_udp_hdr *)pkt;

	/*
	 * Construct an IP and ICMP header.
	 * (need to set no fragment bit - XXX)
	 */
	/* IP_HDR_SIZE / 4 (not including UDP) */
	ip->ip_hl_v  = 0x45;
	ip->ip_tos   = 0;
	ip->ip_len   = htons(IP_HDR_SIZE + 8);
	ip->ip_id    = htons(NetIPID++);
	ip->ip_off   = htons(IP_FLAGS_DFRAG);	/* Don't fragment */
	ip->ip_ttl   = 255;
	ip->ip_p     = 0x01;		/* ICMP */
	ip->ip_sum   = 0;
	/* already in network byte order */
	NetCopyIP((void *)&ip->ip_src, &NetOurIP);
	/* - "" - */
	NetCopyIP((void *)&ip->ip_dst, &NetPingIP);
	ip->ip_sum   = ~NetCksum((uchar *)ip, IP_HDR_SIZE / 2);

	s = &ip->udp_src;		/* XXX ICMP starts here */
	s[0] = htons(0x0800);		/* echo-request, code */
	s[1] = 0;			/* checksum */
	s[2] = 0;			/* identifier */
	s[3] = htons(PingSeqNo++);	/* sequence number */
	s[1] = ~NetCksum((uchar *)s, 8/2);

	/* size of the waiting packet */
	NetArpWaitTxPacketSize =
		(pkt - NetArpWaitTxPacket) + IP_HDR_SIZE + 8;

	/* and do the ARP request */
	NetArpWaitTry = 1;
	NetArpWaitTimerStart = get_timer(0);
	ArpRequest();
	return 1;	/* waiting */
}

static void ping_timeout(void)
{
	eth_halt();
	NetState = NETLOOP_FAIL;	/* we did not get the reply */
}

static void ping_handler(uchar *pkt, unsigned dest, IPaddr_t sip,
	    unsigned src, unsigned len)
{
	if (sip != NetPingIP)
		return;

	NetState = NETLOOP_SUCCESS;
}

void ping_start(void)
{
	printf("Using %s device\n", eth_get_name());
	NetSetTimeout(10000UL, ping_timeout);
	NetSetHandler(ping_handler);

	ping_send();
}

void ping_receive(Ethernet_t *et, struct ip_udp_hdr *ip, int len)
{
	ICMP_t *icmph = (ICMP_t *)&(ip->udp_src);
	IPaddr_t src_ip;

	switch (icmph->type) {
	case ICMP_ECHO_REPLY:
		/*
		 * IP header OK.  Pass the packet to the
		 * current handler.
		 */
		/* XXX point to ip packet */
		src_ip = NetReadIP((void *)&ip->ip_src);
		NetGetHandler()((uchar *)ip, 0, src_ip, 0, 0);
		return;
	case ICMP_ECHO_REQUEST:
		debug("Got ICMP ECHO REQUEST, return "
			"%d bytes\n", ETHER_HDR_SIZE + len);

		memcpy(&et->et_dest[0], &et->et_src[0], 6);
		memcpy(&et->et_src[0], NetOurEther, 6);

		ip->ip_sum = 0;
		ip->ip_off = 0;
		NetCopyIP((void *)&ip->ip_dst, &ip->ip_src);
		NetCopyIP((void *)&ip->ip_src, &NetOurIP);
		ip->ip_sum = ~NetCksum((uchar *)ip,
				       IP_HDR_SIZE >> 1);

		icmph->type = ICMP_ECHO_REPLY;
		icmph->checksum = 0;
		icmph->checksum = ~NetCksum((uchar *)icmph,
			(len - IP_HDR_SIZE) >> 1);
		(void) eth_send((uchar *)et,
				ETHER_HDR_SIZE + len);
		return;
/*	default:
		return;*/
	}
}