Networking code for BMP LPC1768. More...

#include <string.h>
#include "lpc17xx.h"
#include "bmp.h"

Data Structures
struct	arp_pkt_t
	ARP packet definition. More...

struct	udp_hdr_t
	UDP header. More...

struct	icmp_hdr_t
	ICMP header; only ECHO request and reply are supported. More...

struct	mac_hdr_t
	Ethernet packet header; will be followed by ip_hdr_t or arp_pkt_t. More...

struct	ip_hdr_t
	IP header; will be followed by udp_hdr_t or icmp_hdr_t. More...

struct	msg_queue_t
	The type of the message queue. This is a circular buffer. More...

Macros
#define	ETHERNET_SIZE_MAX 384
	Maximum size of ethernet message. Larger messages are ignored.

#define	ntohs(t) ((((t) & 0x00ff) << 8) \| (((t) & 0xff00) >> 8))
	Byteswap: network to host short.

#define	htons(t) ((((t) & 0x00ff) << 8) \| (((t) & 0xff00) >> 8))
	Byteswap: host to network short.

#define	MAC_HDR_SIZE 14
	Size of Ethernet header (mac_hdr_t)

#define	IP_HDR_SIZE 20
	Size of IP header (ip_hdr_t)

#define	UDP_HDR_SIZE 8
	Size of UDP header (udp_hdr_t)

#define	SDP_PAD_SIZE 2
	Size of SDP header (sdp_msg_t)

#define	IP_HDR_OFFSET MAC_HDR_SIZE
	Offset to IP header in Ethernet packet.

#define	IP_DATA_OFFSET (IP_HDR_OFFSET + IP_HDR_SIZE)
	Offset to IP body in Ethernet packet.

#define	UDP_HDR_OFFSET IP_DATA_OFFSET
	Offset to UDP header in Ethernet packet.

#define	UDP_DATA_OFFSET (UDP_HDR_OFFSET + UDP_HDR_SIZE)
	Offset to UDP body in Ethernet packet.

#define	NUM_MSGS 8
	The number of messages we have allocated.

#define	MAX_MSG (NUM_MSGS - 1)
	The maximum message number, for allocation purposes.

#define	MSG_QUEUE_SIZE NUM_MSGS
	Size of the message queue.

Enumerations
enum	ethernet_packet_types { ETYPE_IP = 0x0800 , ETYPE_ARP = 0x0806 }
	Types of Ethernet packets we understand. More...

enum	internet_protocol_packet_types { PROT_ICMP = 1 , PROT_UDP = 17 }
	Types of IP packets we understand. More...

enum	arp_opcodes { ARP_REQ = 1 , ARP_REPLY = 2 }
	ARP operations we know about. More...

enum	icmp_commands { ICMP_ECHO_REPLY = 0 , ICMP_ECHO_REQ = 8 }
	ICMP operations we know about. More...

Functions
void	msg_init (void)
	Initialise the message queue.

sdp_msg_t *	msg_get (void)
	"Allocate" a message from the free message pool

static void	msg_free (sdp_msg_t *msg)
	"Free" a message, returning it to the free message pool

uint32_t	msg_queue_insert (sdp_msg_t *msg)
	Insert a message in the message queue.

sdp_msg_t *	msg_queue_remove (void)
	Get a message from the head of the message queue and remove it from the queue.

uint32_t	msg_queue_size (void)
	How big is the message queue?

static uint32_t	ipsum (const uint8_t *d, uint32_t len, uint32_t sum)
	Compute a checksum using IP rules.

static void	copy_mac (const uint8_t restrict f, uint8_t restrict t)
	Copy MAC address.

void	copy_ip (const uint8_t restrict f, uint8_t restrict t)
	Copy IP address.

uint32_t	cmp_ip (const uint8_t a, const uint8_t b)
	Compare two IP addresses.

void	iptag_timer (void)
	IPTag timeout tick. Called from proc_100hz() every 10ms.

uint32_t	iptag_new (void)
	Allocate a transient IPTag.

uint32_t	transient_tag (uint8_t ip, uint8_t mac, uint32_t port, uint32_t timeout)
	Allocate and initialise a transient IPTag.

void	copy_ip_hdr (uint8_t dest, uint32_t prot, ip_hdr_t ip, uint32_t len)
	Initialise IP header information.

void	copy_udp (uint8_t *buf, uint32_t len, uint32_t dest, uint32_t srce)
	Initialise UDP header information.

static void	eth_transmit (uint8_t buf, uint32_t len, uint32_t type, const uint8_t dest)
	Send an ethernet packet.

static void	send_arp_pkt (uint8_t buf, const uint8_t dest, const uint8_t tha, const uint8_t tpa, uint32_t type)
	Send an ARP packet.

static void	arp_pkt (uint8_t *buf, uint32_t rx_len)
	Handle a received ARP packet.

static void	icmp_pkt (uint8_t *buf, uint32_t rx_len)
	Handle a received ICMP packet.

static void	udp_pkt (uint8_t *rx_pkt, uint32_t rx_len)
	Handle a received UDP packet.

void	eth_receive (void)
	Receive a packet off the ethernet hardware.

static void	eth_transmit2 (uint8_t hdr, uint8_t buf, uint32_t len, uint8_t *dest)
	Send an ethernet message.

static void	eth_send_msg (uint32_t tag, sdp_msg_t *msg)
	Send an SDP message over the ethernet port.

static void	swap_sdp_hdr (sdp_msg_t *msg)
	Swap source and destination in an SDP message header.

static void	return_msg (sdp_msg_t *msg, uint32_t rc)
	Returns a message to sender, if sender asked for a response.

void	route_msg (sdp_msg_t *msg)
	Route a message to its destination.

void	arp_lookup (iptag_t *iptag)
	Request an ARP lookup.

void	eth_putc (uint32_t c)
	Add character to ethernet-directed output stream.

void	copy_ip_data (void)
	Copy IP address data from Flash (bmp_flash_ip and spin_flash_ip)

Variables
static uint8_t	eth_buf [ETHERNET_SIZE_MAX]
	Buffer used to mediate with ethernet hardware.

iptag_t	tag_table [TAG_TABLE_SIZE]
	The table of IPTags.

static sdp_msg_t	msg_bufs [NUM_MSGS]
	The allocatable message buffers.

static sdp_msg_t *	msg_root
	Pointer to the next message to allocate.

static uint32_t	msg_count
	The number of allocated messages.

static uint32_t	msg_max
	The maximum value of msg_count.

static msg_queue_t	msg_queue
	The message queue.

static const uint8_t	bc_mac [] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
	Broadcast MAC address.

static const uint8_t	zero_mac [] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
	Network MAC address.

ip_data_t	spin_ip
	IP address of the board we manage.

ip_data_t	bmp_ip
	Our own IP address.

uint32_t	tag_tto = 9
	Tag timeout: 2.56s = 10ms * (1 << (9-1))

static uint8_t	tube_buf [ETHERNET_SIZE_MAX]
	Accumulates chars to write to host.

static uint32_t	tube_ptr
	Point in tube_buf to write.

Detailed Description

Networking code for BMP LPC1768.

Copyright: © The University of Manchester - 2012-2015

Author: Steve Temple, APT Group, School of Computer Science

Data Structure Documentation

◆ arp_pkt_t

struct arp_pkt_t

ARP packet definition.

Data Fields
uint16_t	htype	Hardware address type code.
uint16_t	ptype	Protocol address type code.
uint8_t	hlen	Hardware address length.
uint8_t	plen	Protocol address length.
uint16_t	op	Operation code (see arp_opcodes)
uint8_t	sha[6]	Source hardware address.
uint8_t	spa[4]	Source protocol address.
uint8_t	tha[6]	Target hardware address.
uint8_t	tpa[4]	Target protocol address.

◆ udp_hdr_t

struct udp_hdr_t

UDP header.

Data Fields
uint16_t	srce	Source port.
uint16_t	dest	Destination port.
uint16_t	length	Length of UDP header and payload.
uint16_t	checksum	Checksum of header and data.

◆ icmp_hdr_t

struct icmp_hdr_t

ICMP header; only ECHO request and reply are supported.

Data Fields
uint8_t	type	ICMP message type (icmp_commands)
uint8_t	code	ICMP message subtype.
uint16_t	checksum	Checksum of ICMP message.
uint16_t	ident	Identifier (for ECHO)
uint16_t	seq	Sequence number (for ECHO)

◆ mac_hdr_t

struct mac_hdr_t

Ethernet packet header; will be followed by ip_hdr_t or arp_pkt_t.

Note: This is 14 bytes long; following data is not aligned!

Data Fields
uint8_t	dest[6]	Destination MAC address.
uint8_t	srce[6]	Source MAC address.
uint16_t	type	Packet type (ethernet_packet_types)

◆ ip_hdr_t

struct ip_hdr_t

IP header; will be followed by udp_hdr_t or icmp_hdr_t.

Data Fields
uint8_t	ver_len	Version and header length.
uint8_t	DS	Differentiated service flags.
uint16_t	length	Packet length.
uint16_t	ident	Packet identifier.
uint16_t	flg_off	Flags and fragment offset.
uint8_t	TTL	Time-to-live of packet.
uint8_t	protocol	Sub-protocol code (internet_protocol_packet_types)
uint16_t	checksum	Header checksum.
uint8_t	srce[4]	Source IP address.
uint8_t	dest[4]	Destination IP address.

◆ msg_queue_t

struct msg_queue_t

The type of the message queue. This is a circular buffer.

Data Fields
uint8_t	insert	Where the next message is to be inserted.
uint8_t	remove	Where the next message is to be removed.
volatile uint8_t	count	Number of messages in the queue.
uint8_t	max	Maximum number of messages in the queue
sdp_msg_t *	queue[MSG_QUEUE_SIZE]	The storage for the message queue.

Enumeration Type Documentation

◆ ethernet_packet_types

enum ethernet_packet_types

Types of Ethernet packets we understand.

Enumerator
ETYPE_IP	Message is an IP message.
ETYPE_ARP	Message is an ARP message.

◆ internet_protocol_packet_types

enum internet_protocol_packet_types

Types of IP packets we understand.

Enumerator
PROT_ICMP	Message is an ICMP message.
PROT_UDP	Message is a UDP message.

◆ arp_opcodes

enum arp_opcodes

ARP operations we know about.

Enumerator
ARP_REQ	Message is an ARP request.
ARP_REPLY	Message is an ARP reply.

◆ icmp_commands

enum icmp_commands

ICMP operations we know about.

Enumerator
ICMP_ECHO_REPLY	Message is an ECHO reply.
ICMP_ECHO_REQ	Message is an ECHO request.

Function Documentation

◆ msg_get()

sdp_msg_t * msg_get ( void )

"Allocate" a message from the free message pool

Returns: The message, or NULL if the pool is empty

◆ msg_free()

static void msg_free ( sdp_msg_t * msg )

static

"Free" a message, returning it to the free message pool

Parameters

[in] msg The message to free. Must not be used after this call.

◆ msg_queue_insert()

uint32_t msg_queue_insert ( sdp_msg_t * msg )

Insert a message in the message queue.

Parameters

[in] msg The message to enqueue

Returns: True if the message was enqueued, false if the queue was full

◆ msg_queue_remove()

sdp_msg_t * msg_queue_remove ( void )

Get a message from the head of the message queue and remove it from the queue.

Returns: the message, or NULL if the queue is empty

◆ msg_queue_size()

uint32_t msg_queue_size ( void )

How big is the message queue?

Returns: The number of messages in the queue

◆ ipsum()

static uint32_t ipsum	(	const uint8_t *	d,
		uint32_t	len,
		uint32_t	sum
	)

static

Compute a checksum using IP rules.

Parameters

[in]	d	The buffer to compute the checksum of
[in]	len	The length of buffer in `d`
[in]	sum	Existing checksum value to accumulate to; use 0 for first step

Returns: the checksum

◆ copy_mac()

static void copy_mac	(	const uint8_t *restrict	f,
		uint8_t *restrict	t
	)

static

Copy MAC address.

Parameters

[in]	f	Where to copy from
[out]	t	Where to copy to

◆ copy_ip()

void copy_ip	(	const uint8_t *restrict	f,
		uint8_t *restrict	t
	)

Copy IP address.

Parameters

[in]	f	Where to copy from
[out]	t	Where to copy to

◆ cmp_ip()

uint32_t cmp_ip	(	const uint8_t *	a,
		const uint8_t *	b
	)

Compare two IP addresses.

Parameters

[in]	a	IP address 1
[in]	b	IP address 2

Returns: true if they are equal, false if they differ

◆ iptag_new()

uint32_t iptag_new ( void )

Allocate a transient IPTag.

Returns: The IPTag ID, or TAG_NONE if allocation failed

◆ transient_tag()

uint32_t transient_tag	(	uint8_t *	ip,
		uint8_t *	mac,
		uint32_t	port,
		uint32_t	timeout
	)

Allocate and initialise a transient IPTag.

Parameters

ip	Source IP address
mac	Sender MAC address (probably gateway)
port	Sender UDP port
timeout	Timeout associated with IPTag (number of 10ms ticks the tag is to live for)

Returns: The IPTag ID, or TAG_NONE if allocation failed

◆ copy_ip_hdr()

void copy_ip_hdr	(	uint8_t *	dest,
		uint32_t	prot,
		ip_hdr_t *	ip,
		uint32_t	len
	)

Initialise IP header information.

Parameters

[in]	dest	Destination IP address
[in]	prot	IP sub-protocol
[out]	ip	Buffer holding IP header
[in]	len	Length of whole message

◆ copy_udp()

void copy_udp	(	uint8_t *	buf,
		uint32_t	len,
		uint32_t	dest,
		uint32_t	srce
	)

Initialise UDP header information.

Parameters

[in,out]	buf	Buffer holding whole Ethernet message
[in]	len	Length of message payload
[in]	dest	Destination UDP port
[in]	srce	Source UDP port

◆ eth_transmit()

static void eth_transmit	(	uint8_t *	buf,
		uint32_t	len,
		uint32_t	type,
		const uint8_t *	dest
	)

static

Send an ethernet packet.

Writes to the packet header; body must be supplied.

Parameters

[in]	buf	The buffer holding the ethernet packet
[in]	len	Length of whole message in `buf`
[in]	type	The message type
[in]	dest	The destination MAC address

◆ send_arp_pkt()

static void send_arp_pkt	(	uint8_t *	buf,
		const uint8_t *	dest,
		const uint8_t *	tha,
		const uint8_t *	tpa,
		uint32_t	type
	)

static

Send an ARP packet.

Writes to the packet header; body must be supplied.

Parameters

[in]	buf	The buffer holding the ARP packet, including space for all headers
[in]	dest	The destination MAC address
[in]	tha	Target hardware address (MAC)
[in]	tpa	Target protocol address (IP)
[in]	type	ARP operation

◆ arp_pkt()

static void arp_pkt	(	uint8_t *	buf,
		uint32_t	rx_len
	)

static

Handle a received ARP packet.

Parameters

[in]	buf	The received message, including ethernet headers
[in]	rx_len	The received length

◆ icmp_pkt()

static void icmp_pkt	(	uint8_t *	buf,
		uint32_t	rx_len
	)

static

Handle a received ICMP packet.

Parameters

[in]	buf	The received message, including ethernet headers
[in]	rx_len	The received length

◆ udp_pkt()

static void udp_pkt	(	uint8_t *	rx_pkt,
		uint32_t	rx_len
	)

static

Handle a received UDP packet.

Parameters

[in]	rx_pkt	The received message, including ethernet headers
[in]	rx_len	The received length

◆ eth_receive()

void eth_receive ( void )

Receive a packet off the ethernet hardware.

Delegates to:

◆ eth_transmit2()

static void eth_transmit2	(	uint8_t *	hdr,
		uint8_t *	buf,
		uint32_t	len,
		uint8_t *	dest
	)

static

Send an ethernet message.

Parameters

[in]	hdr	The ethernet + UDP headers
[in]	buf	The buffer holding the message payload
[in]	len	Length of payload in `buf`
[in]	dest	The destination MAC address

◆ eth_send_msg()

static void eth_send_msg	(	uint32_t	tag,
		sdp_msg_t *	msg
	)

static

Send an SDP message over the ethernet port.

Parameters

[in]	tag	The index of the IPTag that describes the destination
[in]	msg	The SDP message to send

◆ swap_sdp_hdr()

static void swap_sdp_hdr ( sdp_msg_t * msg )

static

Swap source and destination in an SDP message header.

This reflects the message so it can become its own reply

Parameters

[in] msg The message to be swapped

◆ return_msg()

static void return_msg	(	sdp_msg_t *	msg,
		uint32_t	rc
	)

static

Returns a message to sender, if sender asked for a response.

Parameters

[in]	msg	The message to return. Ownership of the message is taken! Caller must not use the message after this.
[in]	rc	Response code. Non-zero indicates an error (when only header information is used). Zero is an OK response, in which case the payload and length of the message should be set correctly.

◆ route_msg()

void route_msg ( sdp_msg_t * msg )

Route a message to its destination.

Parameters

[in] msg The message to route. Ownership of the message is taken! Caller must not use the message after this.

◆ arp_lookup()

void arp_lookup ( iptag_t * iptag )

Request an ARP lookup.

Parameters

[in] iptag The IPTag to do the lookup for

◆ eth_putc()

void eth_putc ( uint32_t c )

Add character to ethernet-directed output stream.

If the buffer is full or at end of line, push the buffer to the configured host machine.

Parameters

[in] c The character to write

Data Structures

Macros

Enumerations

Functions

Variables

Detailed Description

Data Structure Documentation

◆ arp_pkt_t

◆ udp_hdr_t

◆ icmp_hdr_t

◆ mac_hdr_t

◆ ip_hdr_t

◆ msg_queue_t

Enumeration Type Documentation

◆ ethernet_packet_types

◆ internet_protocol_packet_types

◆ arp_opcodes

◆ icmp_commands

Function Documentation

◆ msg_get()

◆ msg_free()

◆ msg_queue_insert()

◆ msg_queue_remove()

◆ msg_queue_size()

◆ ipsum()

◆ copy_mac()

◆ copy_ip()

◆ cmp_ip()

◆ iptag_new()

◆ transient_tag()

◆ copy_ip_hdr()

◆ copy_udp()

◆ eth_transmit()

◆ send_arp_pkt()

◆ arp_pkt()

◆ icmp_pkt()

◆ udp_pkt()

◆ eth_receive()

◆ eth_transmit2()

◆ eth_send_msg()

◆ swap_sdp_hdr()

◆ return_msg()

◆ route_msg()

◆ arp_lookup()

◆ eth_putc()