net.c

	const uchar *t;
	const ushort *ss;
	ushort type, tlen;
	uchar applid;
	ushort vlan, nvlan;

	/* minimum size? */
	if (len < sizeof(CDP_SNAP_hdr) + 4)
		goto pkt_short;

	/* check for valid CDP SNAP header */
	if (memcmp(pkt, CDP_SNAP_hdr, sizeof(CDP_SNAP_hdr)) != 0)
		return;

	pkt += sizeof(CDP_SNAP_hdr);
	len -= sizeof(CDP_SNAP_hdr);

	/* Version of CDP protocol must be >= 2 and TTL != 0 */
	if (pkt[0] < 0x02 || pkt[1] == 0)
		return;

	/* if version is greater than 0x02 maybe we'll have a problem; output a warning */
	if (pkt[0] != 0x02)
		printf("** WARNING: CDP packet received with a protocol version %d > 2\n",
				pkt[0] & 0xff);

	if (CDP_compute_csum(pkt, len) != 0)
		return;

	pkt += 4;
	len -= 4;

	vlan = htons(-1);
	nvlan = htons(-1);
	while (len > 0) {
		if (len < 4)
			goto pkt_short;

		ss = (const ushort *)pkt;
		type = ntohs(ss[0]);
		tlen = ntohs(ss[1]);
		if (tlen > len) {
			goto pkt_short;
		}

		pkt += tlen;
		len -= tlen;

		ss += 2;	/* point ss to the data of the TLV */
		tlen -= 4;

		switch (type) {
			case CDP_DEVICE_ID_TLV:
				break;
			case CDP_ADDRESS_TLV:
				break;
			case CDP_PORT_ID_TLV:
				break;
			case CDP_CAPABILITIES_TLV:
				break;
			case CDP_VERSION_TLV:
				break;
			case CDP_PLATFORM_TLV:
				break;
			case CDP_NATIVE_VLAN_TLV:
				nvlan = *ss;
				break;
			case CDP_APPLIANCE_VLAN_TLV:
				t = (const uchar *)ss;
				while (tlen > 0) {
					if (tlen < 3)
						goto pkt_short;

					applid = t[0];
					ss = (const ushort *)(t + 1);

#ifdef CONFIG_CDP_APPLIANCE_VLAN_TYPE
					if (applid == CONFIG_CDP_APPLIANCE_VLAN_TYPE)
						vlan = *ss;
#else
					vlan = ntohs(*ss);	/* XXX will this work; dunno */
#endif
					t += 3; tlen -= 3;
				}
				break;
			case CDP_TRIGGER_TLV:
				break;
			case CDP_POWER_CONSUMPTION_TLV:
				break;
			case CDP_SYSNAME_TLV:
				break;
			case CDP_SYSOBJECT_TLV:
				break;
			case CDP_MANAGEMENT_ADDRESS_TLV:
				break;
		}
	}

	CDPApplianceVLAN = vlan;
	CDPNativeVLAN = nvlan;

	CDPOK = 1;
	return;

 pkt_short:
	printf("** CDP packet is too short\n");
	return;
}

static void CDPStart(void)
{
#if defined(CONFIG_NET_MULTI)
	printf ("Using %s device\n", eth_get_name());
#endif
	CDPSeq = 0;
	CDPOK = 0;

	CDPNativeVLAN = htons(-1);
	CDPApplianceVLAN = htons(-1);

	NetSetTimeout (CDP_TIMEOUT, CDPTimeout);
	NetSetHandler (CDPDummyHandler);

	CDPSendTrigger();
}
#endif

#ifdef CONFIG_IP_DEFRAG
/*
 * This function collects fragments in a single packet, according
 * to the algorithm in RFC815. It returns NULL or the pointer to
 * a complete packet, in static storage
 */
#ifndef CONFIG_NET_MAXDEFRAG
#define CONFIG_NET_MAXDEFRAG 16384
#endif
/*
 * MAXDEFRAG, above, is chosen in the config file and  is real data
 * so we need to add the NFS overhead, which is more than TFTP.
 * To use sizeof in the internal unnamed structures, we need a real
 * instance (can't do "sizeof(struct rpc_t.u.reply))", unfortunately).
 * The compiler doesn't complain nor allocates the actual structure
 */
static struct rpc_t rpc_specimen;
#define IP_PKTSIZE (CONFIG_NET_MAXDEFRAG + sizeof(rpc_specimen.u.reply))

#define IP_MAXUDP (IP_PKTSIZE - IP_HDR_SIZE_NO_UDP)

/*
 * this is the packet being assembled, either data or frag control.
 * Fragments go by 8 bytes, so this union must be 8 bytes long
 */
struct hole {
	/* first_byte is address of this structure */
	u16 last_byte;	/* last byte in this hole + 1 (begin of next hole) */
	u16 next_hole;	/* index of next (in 8-b blocks), 0 == none */
	u16 prev_hole;	/* index of prev, 0 == none */
	u16 unused;
};

static IP_t *__NetDefragment(IP_t *ip, int *lenp)
{
	static uchar pkt_buff[IP_PKTSIZE] __attribute__((aligned(PKTALIGN)));
	static u16 first_hole, total_len;
	struct hole *payload, *thisfrag, *h, *newh;
	IP_t *localip = (IP_t *)pkt_buff;
	uchar *indata = (uchar *)ip;
	int offset8, start, len, done = 0;
	u16 ip_off = ntohs(ip->ip_off);

	/* payload starts after IP header, this fragment is in there */
	payload = (struct hole *)(pkt_buff + IP_HDR_SIZE_NO_UDP);
	offset8 =  (ip_off & IP_OFFS);
	thisfrag = payload + offset8;
	start = offset8 * 8;
	len = ntohs(ip->ip_len) - IP_HDR_SIZE_NO_UDP;

	if (start + len > IP_MAXUDP) /* fragment extends too far */
		return NULL;

	if (!total_len || localip->ip_id != ip->ip_id) {
		/* new (or different) packet, reset structs */
		total_len = 0xffff;
		payload[0].last_byte = ~0;
		payload[0].next_hole = 0;
		payload[0].prev_hole = 0;
		first_hole = 0;
		/* any IP header will work, copy the first we received */
		memcpy(localip, ip, IP_HDR_SIZE_NO_UDP);
	}

	/*
	 * What follows is the reassembly algorithm. We use the payload
	 * array as a linked list of hole descriptors, as each hole starts
	 * at a multiple of 8 bytes. However, last byte can be whatever value,
	 * so it is represented as byte count, not as 8-byte blocks.
	 */

	h = payload + first_hole;
	while (h->last_byte < start) {
		if (!h->next_hole) {
			/* no hole that far away */
			return NULL;
		}
		h = payload + h->next_hole;
	}

	/* last fragment may be 1..7 bytes, the "+7" forces acceptance */
	if (offset8 + ((len + 7) / 8) <= h - payload) {
		/* no overlap with holes (dup fragment?) */
		return NULL;
	}

	if (!(ip_off & IP_FLAGS_MFRAG)) {
		/* no more fragmentss: truncate this (last) hole */
		total_len = start + len;
		h->last_byte = start + len;
	}

	/*
	 * There is some overlap: fix the hole list. This code doesn't
	 * deal with a fragment that overlaps with two different holes
	 * (thus being a superset of a previously-received fragment).
	 */

	if ( (h >= thisfrag) && (h->last_byte <= start + len) ) {
		/* complete overlap with hole: remove hole */
		if (!h->prev_hole && !h->next_hole) {
			/* last remaining hole */
			done = 1;
		} else if (!h->prev_hole) {
			/* first hole */
			first_hole = h->next_hole;
			payload[h->next_hole].prev_hole = 0;
		} else if (!h->next_hole) {
			/* last hole */
			payload[h->prev_hole].next_hole = 0;
		} else {
			/* in the middle of the list */
			payload[h->next_hole].prev_hole = h->prev_hole;
			payload[h->prev_hole].next_hole = h->next_hole;
		}

	} else if (h->last_byte <= start + len) {
		/* overlaps with final part of the hole: shorten this hole */
		h->last_byte = start;

	} else if (h >= thisfrag) {
		/* overlaps with initial part of the hole: move this hole */
		newh = thisfrag + (len / 8);
		*newh = *h;
		h = newh;
		if (h->next_hole)
			payload[h->next_hole].prev_hole = (h - payload);
		if (h->prev_hole)
			payload[h->prev_hole].next_hole = (h - payload);
		else
			first_hole = (h - payload);

	} else {
		/* fragment sits in the middle: split the hole */
		newh = thisfrag + (len / 8);
		*newh = *h;
		h->last_byte = start;
		h->next_hole = (newh - payload);
		newh->prev_hole = (h - payload);
		if (newh->next_hole)
			payload[newh->next_hole].prev_hole = (newh - payload);
	}

	/* finally copy this fragment and possibly return whole packet */
	memcpy((uchar *)thisfrag, indata + IP_HDR_SIZE_NO_UDP, len);
	if (!done)
		return NULL;

	localip->ip_len = htons(total_len);
	*lenp = total_len + IP_HDR_SIZE_NO_UDP;
	return localip;
}

static inline IP_t *NetDefragment(IP_t *ip, int *lenp)
{
	u16 ip_off = ntohs(ip->ip_off);
	if (!(ip_off & (IP_OFFS | IP_FLAGS_MFRAG)))
		return ip; /* not a fragment */
	return __NetDefragment(ip, lenp);
}

#else /* !CONFIG_IP_DEFRAG */

static inline IP_t *NetDefragment(IP_t *ip, int *lenp)
{
	u16 ip_off = ntohs(ip->ip_off);
	if (!(ip_off & (IP_OFFS | IP_FLAGS_MFRAG)))
		return ip; /* not a fragment */
	return NULL;
}
#endif

void
NetReceive(volatile uchar * inpkt, int len)
{
	Ethernet_t *et;
	IP_t	*ip;
	ARP_t	*arp;
	IPaddr_t tmp;
	int	x;
	uchar *pkt;
#if defined(CONFIG_CMD_CDP)
	int iscdp;
#endif
	ushort cti = 0, vlanid = VLAN_NONE, myvlanid, mynvlanid;

	debug("packet received\n");

	NetRxPacket = inpkt;
	NetRxPacketLen = len;
	et = (Ethernet_t *)inpkt;

	/* too small packet? */
	if (len < ETHER_HDR_SIZE)
		return;

#ifdef CONFIG_API
	if (push_packet) {
		(*push_packet)(inpkt, len);
		return;
	}
#endif

#if defined(CONFIG_CMD_CDP)
	/* keep track if packet is CDP */
	iscdp = memcmp(et->et_dest, NetCDPAddr, 6) == 0;
#endif

	myvlanid = ntohs(NetOurVLAN);
	if (myvlanid == (ushort)-1)
		myvlanid = VLAN_NONE;
	mynvlanid = ntohs(NetOurNativeVLAN);
	if (mynvlanid == (ushort)-1)
		mynvlanid = VLAN_NONE;

	x = ntohs(et->et_protlen);

	debug("packet received\n");

	if (x < 1514) {
		/*
		 *	Got a 802 packet.  Check the other protocol field.
		 */
		x = ntohs(et->et_prot);

		ip = (IP_t *)(inpkt + E802_HDR_SIZE);
		len -= E802_HDR_SIZE;

	} else if (x != PROT_VLAN) {	/* normal packet */
		ip = (IP_t *)(inpkt + ETHER_HDR_SIZE);
		len -= ETHER_HDR_SIZE;

	} else {			/* VLAN packet */
		VLAN_Ethernet_t *vet = (VLAN_Ethernet_t *)et;

		debug("VLAN packet received\n");

		/* too small packet? */
		if (len < VLAN_ETHER_HDR_SIZE)
			return;

		/* if no VLAN active */
		if ((ntohs(NetOurVLAN) & VLAN_IDMASK) == VLAN_NONE
#if defined(CONFIG_CMD_CDP)
				&& iscdp == 0
#endif
				)
			return;

		cti = ntohs(vet->vet_tag);
		vlanid = cti & VLAN_IDMASK;
		x = ntohs(vet->vet_type);

		ip = (IP_t *)(inpkt + VLAN_ETHER_HDR_SIZE);
		len -= VLAN_ETHER_HDR_SIZE;
	}

	debug("Receive from protocol 0x%x\n", x);

#if defined(CONFIG_CMD_CDP)
	if (iscdp) {
		CDPHandler((uchar *)ip, len);
		return;
	}
#endif

	if ((myvlanid & VLAN_IDMASK) != VLAN_NONE) {
		if (vlanid == VLAN_NONE)
			vlanid = (mynvlanid & VLAN_IDMASK);
		/* not matched? */
		if (vlanid != (myvlanid & VLAN_IDMASK))
			return;
	}

	switch (x) {

	case PROT_ARP:
		/*
		 * We have to deal with two types of ARP packets:
		 * - REQUEST packets will be answered by sending  our
		 *   IP address - if we know it.
		 * - REPLY packates are expected only after we asked
		 *   for the TFTP server's or the gateway's ethernet
		 *   address; so if we receive such a packet, we set
		 *   the server ethernet address
		 */
		debug("Got ARP\n");

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

		if (NetOurIP == 0) {
			return;
		}

		if (NetReadIP(&arp->ar_data[16]) != NetOurIP) {
			return;
		}

		switch (ntohs(arp->ar_op)) {
		case ARPOP_REQUEST:		/* reply with our IP address	*/
			debug("Got ARP REQUEST, return our IP\n");
			pkt = (uchar *)et;
			pkt += NetSetEther(pkt, et->et_src, PROT_ARP);
			arp->ar_op = htons(ARPOP_REPLY);
			memcpy   (&arp->ar_data[10], &arp->ar_data[0], 6);
			NetCopyIP(&arp->ar_data[16], &arp->ar_data[6]);
			memcpy   (&arp->ar_data[ 0], NetOurEther, 6);
			NetCopyIP(&arp->ar_data[ 6], &NetOurIP);
			(void) eth_send((uchar *)et, (pkt - (uchar *)et) + ARP_HDR_SIZE);
			return;

		case ARPOP_REPLY:		/* arp reply */
			/* are we waiting for a reply */
			if (!NetArpWaitPacketIP || !NetArpWaitPacketMAC)
				break;

#ifdef CONFIG_KEEP_SERVERADDR
			if (NetServerIP == NetArpWaitPacketIP) {
				char buf[20];
				sprintf(buf, "%pM", arp->ar_data);
				setenv("serveraddr", buf);
			}
#endif

			debug("Got ARP REPLY, set server/gtwy eth addr (%pM)\n",
				arp->ar_data);

			tmp = NetReadIP(&arp->ar_data[6]);

			/* matched waiting packet's address */
			if (tmp == NetArpWaitReplyIP) {
				debug("Got it\n");
				/* save address for later use */
				memcpy(NetArpWaitPacketMAC, &arp->ar_data[0], 6);

#ifdef CONFIG_NETCONSOLE
				(*packetHandler)(0,0,0,0);
#endif
				/* modify header, and transmit it */
				memcpy(((Ethernet_t *)NetArpWaitTxPacket)->et_dest, NetArpWaitPacketMAC, 6);
				(void) eth_send(NetArpWaitTxPacket, NetArpWaitTxPacketSize);

				/* no arp request pending now */
				NetArpWaitPacketIP = 0;
				NetArpWaitTxPacketSize = 0;
				NetArpWaitPacketMAC = NULL;

			}
			return;
		default:
			debug("Unexpected ARP opcode 0x%x\n", ntohs(arp->ar_op));
			return;
		}
		break;

#ifdef CONFIG_CMD_RARP
	case PROT_RARP:
		debug("Got RARP\n");
		arp = (ARP_t *)ip;
		if (len < ARP_HDR_SIZE) {
			printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
			return;
		}

		if ((ntohs(arp->ar_op) != RARPOP_REPLY) ||
			(ntohs(arp->ar_hrd) != ARP_ETHER)   ||
			(ntohs(arp->ar_pro) != PROT_IP)     ||
			(arp->ar_hln != 6) || (arp->ar_pln != 4)) {

			puts ("invalid RARP header\n");
		} else {
			NetCopyIP(&NetOurIP,    &arp->ar_data[16]);
			if (NetServerIP == 0)
				NetCopyIP(&NetServerIP, &arp->ar_data[ 6]);
			memcpy (NetServerEther, &arp->ar_data[ 0], 6);

			(*packetHandler)(0,0,0,0);
		}
		break;
#endif
	case PROT_IP:
		debug("Got IP\n");
		/* Before we start poking the header, make sure it is there */
		if (len < IP_HDR_SIZE) {
			debug("len bad %d < %lu\n", len, (ulong)IP_HDR_SIZE);
			return;
		}
		/* Check the packet length */
		if (len < ntohs(ip->ip_len)) {
			printf("len bad %d < %d\n", len, ntohs(ip->ip_len));
			return;
		}
		len = ntohs(ip->ip_len);
		debug("len=%d, v=%02x\n", len, ip->ip_hl_v & 0xff);

		/* Can't deal with anything except IPv4 */
		if ((ip->ip_hl_v & 0xf0) != 0x40) {
			return;
		}
		/* Can't deal with IP options (headers != 20 bytes) */
		if ((ip->ip_hl_v & 0x0f) > 0x05) {
			return;
		}
		/* Check the Checksum of the header */
		if (!NetCksumOk((uchar *)ip, IP_HDR_SIZE_NO_UDP / 2)) {
			puts ("checksum bad\n");
			return;
		}
		/* If it is not for us, ignore it */
		tmp = NetReadIP(&ip->ip_dst);
		if (NetOurIP && tmp != NetOurIP && tmp != 0xFFFFFFFF) {
#ifdef CONFIG_MCAST_TFTP
			if (Mcast_addr != tmp)
#endif
			return;
		}
		/*
		 * The function returns the unchanged packet if it's not
		 * a fragment, and either the complete packet or NULL if
		 * it is a fragment (if !CONFIG_IP_DEFRAG, it returns NULL)
		 */
		if (!(ip = NetDefragment(ip, &len)))
			return;
		/*
		 * watch for ICMP host redirects
		 *
		 * There is no real handler code (yet). We just watch
		 * for ICMP host redirect messages. In case anybody
		 * sees these messages: please contact me
		 * (wd@denx.de), or - even better - send me the
		 * necessary fixes :-)
		 *
		 * Note: in all cases where I have seen this so far
		 * it was a problem with the router configuration,
		 * for instance when a router was configured in the
		 * BOOTP reply, but the TFTP server was on the same
		 * subnet. So this is probably a warning that your
		 * configuration might be wrong. But I'm not really
		 * sure if there aren't any other situations.
		 */
		if (ip->ip_p == IPPROTO_ICMP) {
			ICMP_t *icmph = (ICMP_t *)&(ip->udp_src);

			switch (icmph->type) {
			case ICMP_REDIRECT:
				if (icmph->code != ICMP_REDIR_HOST)
					return;
				printf (" ICMP Host Redirect to %pI4 ", &icmph->un.gateway);
				return;
#if defined(CONFIG_CMD_PING)
			case ICMP_ECHO_REPLY:
				/*
				 *	IP header OK.  Pass the packet to the current handler.
				 */
				/* XXX point to ip packet */
				(*packetHandler)((uchar *)ip, 0, 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_NO_UDP >> 1);

				icmph->type = ICMP_ECHO_REPLY;
				icmph->checksum = 0;
				icmph->checksum = ~NetCksum((uchar *)icmph,
						(len - IP_HDR_SIZE_NO_UDP) >> 1);
				(void) eth_send((uchar *)et, ETHER_HDR_SIZE + len);
				return;
#endif
			default:
				return;
			}
		} else if (ip->ip_p != IPPROTO_UDP) {	/* Only UDP packets */
			return;
		}

#ifdef CONFIG_UDP_CHECKSUM
		if (ip->udp_xsum != 0) {
			ulong   xsum;
			ushort *sumptr;
			ushort  sumlen;

			xsum  = ip->ip_p;
			xsum += (ntohs(ip->udp_len));
			xsum += (ntohl(ip->ip_src) >> 16) & 0x0000ffff;
			xsum += (ntohl(ip->ip_src) >>  0) & 0x0000ffff;
			xsum += (ntohl(ip->ip_dst) >> 16) & 0x0000ffff;
			xsum += (ntohl(ip->ip_dst) >>  0) & 0x0000ffff;

			sumlen = ntohs(ip->udp_len);
			sumptr = (ushort *) &(ip->udp_src);

			while (sumlen > 1) {
				ushort sumdata;

				sumdata = *sumptr++;
				xsum += ntohs(sumdata);
				sumlen -= 2;
			}
			if (sumlen > 0) {
				ushort sumdata;

				sumdata = *(unsigned char *) sumptr;
				sumdata = (sumdata << 8) & 0xff00;
				xsum += sumdata;
			}
			while ((xsum >> 16) != 0) {
				xsum = (xsum & 0x0000ffff) + ((xsum >> 16) & 0x0000ffff);
			}
			if ((xsum != 0x00000000) && (xsum != 0x0000ffff)) {
				printf(" UDP wrong checksum %08lx %08x\n",
					xsum, ntohs(ip->udp_xsum));
				return;
			}
		}
#endif


#ifdef CONFIG_NETCONSOLE
		nc_input_packet((uchar *)ip +IP_HDR_SIZE,
						ntohs(ip->udp_dst),
						ntohs(ip->udp_src),
						ntohs(ip->udp_len) - 8);
#endif
		/*
		 *	IP header OK.  Pass the packet to the current handler.
		 */
		(*packetHandler)((uchar *)ip +IP_HDR_SIZE,
						ntohs(ip->udp_dst),
						ntohs(ip->udp_src),
						ntohs(ip->udp_len) - 8);
		break;
	}
}


/**********************************************************************/

static int net_check_prereq (proto_t protocol)
{
	switch (protocol) {
		/* Fall through */
#if defined(CONFIG_CMD_PING)
	case PING:
		if (NetPingIP == 0) {
			puts ("*** ERROR: ping address not given\n");
			return (1);
		}
		goto common;
#endif
#if defined(CONFIG_CMD_SNTP)
	case SNTP:
		if (NetNtpServerIP == 0) {
			puts ("*** ERROR: NTP server address not given\n");
			return (1);
		}
		goto common;
#endif
#if defined(CONFIG_CMD_DNS)
	case DNS:
		if (NetOurDNSIP == 0) {
			puts("*** ERROR: DNS server address not given\n");
			return 1;
		}
		goto common;
#endif
#if defined(CONFIG_CMD_NFS)
	case NFS:
#endif
	case TFTP:
		if (NetServerIP == 0) {
			puts ("*** ERROR: `serverip' not set\n");
			return (1);
		}
#if defined(CONFIG_CMD_PING) || defined(CONFIG_CMD_SNTP) || \
    defined(CONFIG_CMD_DNS)
    common:
#endif
		/* Fall through */

	case NETCONS:
		if (NetOurIP == 0) {
			puts ("*** ERROR: `ipaddr' not set\n");
			return (1);
		}
		/* Fall through */

#ifdef CONFIG_CMD_RARP
	case RARP:
#endif
	case BOOTP:
	case CDP:
	case DHCP:
		if (memcmp (NetOurEther, "\0\0\0\0\0\0", 6) == 0) {
#ifdef CONFIG_NET_MULTI
			extern int eth_get_dev_index (void);
			int num = eth_get_dev_index ();

			switch (num) {
			case -1:
				puts ("*** ERROR: No ethernet found.\n");
				return (1);
			case 0:
				puts ("*** ERROR: `ethaddr' not set\n");
				break;
			default:
				printf ("*** ERROR: `eth%daddr' not set\n",
					num);
				break;
			}

			NetStartAgain ();
			return (2);
#else
			puts ("*** ERROR: `ethaddr' not set\n");
			return (1);
#endif
		}
		/* Fall through */
	default:
		return (0);
	}
	return (0);		/* OK */
}
/**********************************************************************/

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


unsigned
NetCksum(uchar * ptr, int len)
{
	ulong	xsum;
	ushort *p = (ushort *)ptr;

	xsum = 0;
	while (len-- > 0)
		xsum += *p++;
	xsum = (xsum & 0xffff) + (xsum >> 16);
	xsum = (xsum & 0xffff) + (xsum >> 16);
	return (xsum & 0xffff);
}

int
NetEthHdrSize(void)
{
	ushort myvlanid;

	myvlanid = ntohs(NetOurVLAN);
	if (myvlanid == (ushort)-1)
		myvlanid = VLAN_NONE;

	return ((myvlanid & VLAN_IDMASK) == VLAN_NONE) ? ETHER_HDR_SIZE : VLAN_ETHER_HDR_SIZE;
}

int
NetSetEther(volatile uchar * xet, uchar * addr, uint prot)
{
	Ethernet_t *et = (Ethernet_t *)xet;
	ushort myvlanid;

	myvlanid = ntohs(NetOurVLAN);
	if (myvlanid == (ushort)-1)
		myvlanid = VLAN_NONE;

	memcpy (et->et_dest, addr, 6);
	memcpy (et->et_src, NetOurEther, 6);
	if ((myvlanid & VLAN_IDMASK) == VLAN_NONE) {
	et->et_protlen = htons(prot);
		return ETHER_HDR_SIZE;
	} else {
		VLAN_Ethernet_t *vet = (VLAN_Ethernet_t *)xet;

		vet->vet_vlan_type = htons(PROT_VLAN);
		vet->vet_tag = htons((0 << 5) | (myvlanid & VLAN_IDMASK));
		vet->vet_type = htons(prot);
		return VLAN_ETHER_HDR_SIZE;
	}
}

void
NetSetIP(volatile uchar * xip, IPaddr_t dest, int dport, int sport, int len)
{
	IP_t *ip = (IP_t *)xip;

	/*
	 *	If the data is an odd number of bytes, zero the
	 *	byte after the last byte so that the checksum
	 *	will work.
	 */
	if (len & 1)
		xip[IP_HDR_SIZE + len] = 0;

	/*
	 *	Construct an IP and UDP header.
	 *	(need to set no fragment bit - XXX)
	 */
	ip->ip_hl_v  = 0x45;		/* IP_HDR_SIZE / 4 (not including UDP) */
	ip->ip_tos   = 0;
	ip->ip_len   = htons(IP_HDR_SIZE + len);
	ip->ip_id    = htons(NetIPID++);
	ip->ip_off   = htons(IP_FLAGS_DFRAG);	/* Don't fragment */
	ip->ip_ttl   = 255;
	ip->ip_p     = 17;		/* UDP */
	ip->ip_sum   = 0;
	NetCopyIP((void*)&ip->ip_src, &NetOurIP); /* already in network byte order */
	NetCopyIP((void*)&ip->ip_dst, &dest);	   /* - "" - */
	ip->udp_src  = htons(sport);
	ip->udp_dst  = htons(dport);
	ip->udp_len  = htons(8 + len);
	ip->udp_xsum = 0;
	ip->ip_sum   = ~NetCksum((uchar *)ip, IP_HDR_SIZE_NO_UDP / 2);
}

void copy_filename (char *dst, const char *src, int size)
{
	if (*src && (*src == '"')) {
		++src;
		--size;
	}

	while ((--size > 0) && *src && (*src != '"')) {
		*dst++ = *src++;
	}
	*dst = '\0';
}

#if defined(CONFIG_CMD_NFS) || defined(CONFIG_CMD_SNTP) || defined(CONFIG_CMD_DNS)
/*
 * make port a little random (1024-17407)
 * This keeps the math somewhat trivial to compute, and seems to work with
 * all supported protocols/clients/servers
 */
unsigned int random_port(void)
{
	return 1024 + (get_timer(0) % 0x4000);
}
#endif

void ip_to_string (IPaddr_t x, char *s)
{
	x = ntohl (x);
	sprintf (s, "%d.%d.%d.%d",
		 (int) ((x >> 24) & 0xff),
		 (int) ((x >> 16) & 0xff),
		 (int) ((x >> 8) & 0xff), (int) ((x >> 0) & 0xff)
	);
}

void VLAN_to_string(ushort x, char *s)
{
	x = ntohs(x);

	if (x == (ushort)-1)
		x = VLAN_NONE;

	if (x == VLAN_NONE)
		strcpy(s, "none");
	else
		sprintf(s, "%d", x & VLAN_IDMASK);
}

ushort string_to_VLAN(const char *s)
{
	ushort id;

	if (s == NULL)
		return htons(VLAN_NONE);

	if (*s < '0' || *s > '9')
		id = VLAN_NONE;
	else
		id = (ushort)simple_strtoul(s, NULL, 10);

	return htons(id);
}

ushort getenv_VLAN(char *var)
{
	return (string_to_VLAN(getenv(var)));
}