net.c

	if (eth_proto < 1514) {
		struct e802_hdr *et802 = (struct e802_hdr *)et;
		/*
		 *	Got a 802.2 packet.  Check the other protocol field.
		 *	XXX VLAN over 802.2+SNAP not implemented!
		 */
		eth_proto = ntohs(et802->et_prot);

		ip = (struct ip_udp_hdr *)(in_packet + E802_HDR_SIZE);
		len -= E802_HDR_SIZE;

	} else if (eth_proto != PROT_VLAN) {	/* normal packet */
		ip = (struct ip_udp_hdr *)(in_packet + ETHER_HDR_SIZE);
		len -= ETHER_HDR_SIZE;

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

		debug_cond(DEBUG_NET_PKT, "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;
		eth_proto = ntohs(vet->vet_type);

		ip = (struct ip_udp_hdr *)(in_packet + VLAN_ETHER_HDR_SIZE);
		len -= VLAN_ETHER_HDR_SIZE;
	}

	debug_cond(DEBUG_NET_PKT, "Receive from protocol 0x%x\n", eth_proto);

#if defined(CONFIG_CMD_CDP)
	if (iscdp) {
		cdp_receive((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 (eth_proto) {

	case PROT_ARP:
		arp_receive(et, ip, len);
		break;

#ifdef CONFIG_CMD_RARP
	case PROT_RARP:
		rarp_receive(ip, len);
		break;
#endif
	case PROT_IP:
		debug_cond(DEBUG_NET_PKT, "Got IP\n");
		/* Before we start poking the header, make sure it is there */
		if (len < IP_UDP_HDR_SIZE) {
			debug("len bad %d < %lu\n", len,
				(ulong)IP_UDP_HDR_SIZE);
			return;
		}
		/* Check the packet length */
		if (len < ntohs(ip->ip_len)) {
			debug("len bad %d < %d\n", len, ntohs(ip->ip_len));
			return;
		}
		len = ntohs(ip->ip_len);
		debug_cond(DEBUG_NET_PKT, "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 (!ip_checksum_ok((uchar *)ip, IP_HDR_SIZE)) {
			debug("checksum bad\n");
			return;
		}
		/* If it is not for us, ignore it */
		dst_ip = net_read_ip(&ip->ip_dst);
		if (net_ip.s_addr && dst_ip.s_addr != net_ip.s_addr &&
		    dst_ip.s_addr != 0xFFFFFFFF) {
#ifdef CONFIG_MCAST_TFTP
			if (net_mcast_addr != dst_ip)
#endif
				return;
		}
		/* Read source IP address for later use */
		src_ip = net_read_ip(&ip->ip_src);
		/*
		 * 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)
		 */
		ip = NetDefragment(ip, &len);
		if (!ip)
			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.
		 *
		 * Simon Glass <sjg@chromium.org>: We get an ICMP when
		 * we send a tftp packet to a dead connection, or when
		 * there is no server at the other end.
		 */
		if (ip->ip_p == IPPROTO_ICMP) {
			receive_icmp(ip, len, src_ip, et);
			return;
		} else if (ip->ip_p != IPPROTO_UDP) {	/* Only UDP packets */
			return;
		}

		debug_cond(DEBUG_DEV_PKT,
			"received UDP (to=%pI4, from=%pI4, len=%d)\n",
			&dst_ip, &src_ip, len);

#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.s_addr) >> 16) & 0x0000ffff;
			xsum += (ntohl(ip->ip_src.s_addr) >>  0) & 0x0000ffff;
			xsum += (ntohl(ip->ip_dst.s_addr) >> 16) & 0x0000ffff;
			xsum += (ntohl(ip->ip_dst.s_addr) >>  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


#if defined (CONFIG_NETCONSOLE) && !(CONFIG_SPL_BUILD)
		nc_input_packet((uchar *)ip + IP_UDP_HDR_SIZE,
					src_ip,
					ntohs(ip->udp_dst),
					ntohs(ip->udp_src),
					ntohs(ip->udp_len) - UDP_HDR_SIZE);
#endif
		/*
		 *	IP header OK.  Pass the packet to the current handler.
		 */
		(*udp_packet_handler)((uchar *)ip + IP_UDP_HDR_SIZE,
				ntohs(ip->udp_dst),
				src_ip,
				ntohs(ip->udp_src),
				ntohs(ip->udp_len) - UDP_HDR_SIZE);
		break;
	}
}


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

static int net_check_prereq(enum proto_t protocol)
{
	switch (protocol) {
		/* Fall through */
#if defined(CONFIG_CMD_PING)
	case PING:
		if (net_ping_ip.s_addr == 0) {
			puts("*** ERROR: ping address not given\n");
			return 1;
		}
		goto common;
#endif
#if defined(CONFIG_CMD_SNTP)
	case SNTP:
		if (net_ntp_server.s_addr == 0) {
			puts("*** ERROR: NTP server address not given\n");
			return 1;
		}
		goto common;
#endif
#if defined(CONFIG_CMD_DNS)
	case DNS:
		if (net_dns_server.s_addr == 0) {
			puts("*** ERROR: DNS server address not given\n");
			return 1;
		}
		goto common;
#endif
#if defined(CONFIG_CMD_NFS)
	case NFS:
#endif
	case TFTPGET:
	case TFTPPUT:
		if (net_server_ip.s_addr == 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:
	case TFTPSRV:
		if (net_ip.s_addr == 0) {
			puts("*** ERROR: `ipaddr' not set\n");
			return 1;
		}
		/* Fall through */

#ifdef CONFIG_CMD_RARP
	case RARP:
#endif
	case BOOTP:
	case CDP:
	case DHCP:
	case LINKLOCAL:
		if (memcmp(net_ethaddr, "\0\0\0\0\0\0", 6) == 0) {
			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;
		}
		/* Fall through */
	default:
		return 0;
	}
	return 0;		/* OK */
}
/**********************************************************************/

int
net_eth_hdr_size(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 net_set_ether(uchar *xet, const uchar *dest_ethaddr, uint prot)
{
	struct ethernet_hdr *et = (struct ethernet_hdr *)xet;
	ushort myvlanid;

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

	memcpy(et->et_dest, dest_ethaddr, 6);
	memcpy(et->et_src, net_ethaddr, 6);
	if ((myvlanid & VLAN_IDMASK) == VLAN_NONE) {
		et->et_protlen = htons(prot);
		return ETHER_HDR_SIZE;
	} else {
		struct vlan_ethernet_hdr *vet =
			(struct vlan_ethernet_hdr *)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;
	}
}

int net_update_ether(struct ethernet_hdr *et, uchar *addr, uint prot)
{
	ushort protlen;

	memcpy(et->et_dest, addr, 6);
	memcpy(et->et_src, net_ethaddr, 6);
	protlen = ntohs(et->et_protlen);
	if (protlen == PROT_VLAN) {
		struct vlan_ethernet_hdr *vet =
			(struct vlan_ethernet_hdr *)et;
		vet->vet_type = htons(prot);
		return VLAN_ETHER_HDR_SIZE;
	} else if (protlen > 1514) {
		et->et_protlen = htons(prot);
		return ETHER_HDR_SIZE;
	} else {
		/* 802.2 + SNAP */
		struct e802_hdr *et802 = (struct e802_hdr *)et;
		et802->et_prot = htons(prot);
		return E802_HDR_SIZE;
	}
}

void net_set_ip_header(uchar *pkt, struct in_addr dest, struct in_addr source)
{
	struct ip_udp_hdr *ip = (struct ip_udp_hdr *)pkt;

	/*
	 *	Construct an IP header.
	 */
	/* IP_HDR_SIZE / 4 (not including UDP) */
	ip->ip_hl_v  = 0x45;
	ip->ip_tos   = 0;
	ip->ip_len   = htons(IP_HDR_SIZE);
	ip->ip_id    = htons(NetIPID++);
	ip->ip_off   = htons(IP_FLAGS_DFRAG);	/* Don't fragment */
	ip->ip_ttl   = 255;
	ip->ip_sum   = 0;
	/* already in network byte order */
	net_copy_ip((void *)&ip->ip_src, &source);
	/* already in network byte order */
	net_copy_ip((void *)&ip->ip_dst, &dest);
}

void net_set_udp_header(uchar *pkt, struct in_addr dest, int dport, int sport,
			int len)
{
	struct ip_udp_hdr *ip = (struct ip_udp_hdr *)pkt;

	/*
	 *	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)
		pkt[IP_UDP_HDR_SIZE + len] = 0;

	net_set_ip_header(pkt, dest, net_ip);
	ip->ip_len   = htons(IP_UDP_HDR_SIZE + len);
	ip->ip_p     = IPPROTO_UDP;
	ip->ip_sum   = compute_ip_checksum(ip, IP_HDR_SIZE);

	ip->udp_src  = htons(sport);
	ip->udp_dst  = htons(dport);
	ip->udp_len  = htons(UDP_HDR_SIZE + len);
	ip->udp_xsum = 0;
}

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