net.c

/*
 * IPv4 over IEEE 1394, per RFC 2734
 *
 * Copyright (C) 2009 Jay Fenlason <fenlason@redhat.com>
 *
 * based on eth1394 by Ben Collins et al
 */

#include <linux/bug.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/ethtool.h>
#include <linux/firewire.h>
#include <linux/firewire-constants.h>
#include <linux/highmem.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/jiffies.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <asm/unaligned.h>
#include <net/arp.h>

/* rx limits */
#define FWNET_MAX_FRAGMENTS		30 /* arbitrary, > TX queue depth */
#define FWNET_ISO_PAGE_COUNT		(PAGE_SIZE < 16*1024 ? 4 : 2)

/* tx limits */
#define FWNET_MAX_QUEUED_DATAGRAMS	20 /* < 64 = number of tlabels */
#define FWNET_MIN_QUEUED_DATAGRAMS	10 /* should keep AT DMA busy enough */
#define FWNET_TX_QUEUE_LEN		FWNET_MAX_QUEUED_DATAGRAMS /* ? */

#define IEEE1394_BROADCAST_CHANNEL	31
#define IEEE1394_ALL_NODES		(0xffc0 | 0x003f)
#define IEEE1394_MAX_PAYLOAD_S100	512
#define FWNET_NO_FIFO_ADDR		(~0ULL)

#define IANA_SPECIFIER_ID		0x00005eU
#define RFC2734_SW_VERSION		0x000001U

#define IEEE1394_GASP_HDR_SIZE	8

#define RFC2374_UNFRAG_HDR_SIZE	4
#define RFC2374_FRAG_HDR_SIZE	8
#define RFC2374_FRAG_OVERHEAD	4

#define RFC2374_HDR_UNFRAG	0	/* unfragmented		*/
#define RFC2374_HDR_FIRSTFRAG	1	/* first fragment	*/
#define RFC2374_HDR_LASTFRAG	2	/* last fragment	*/
#define RFC2374_HDR_INTFRAG	3	/* interior fragment	*/

#define RFC2734_HW_ADDR_LEN	16

struct rfc2734_arp {
	__be16 hw_type;		/* 0x0018	*/
	__be16 proto_type;	/* 0x0806       */
	u8 hw_addr_len;		/* 16		*/
	u8 ip_addr_len;		/* 4		*/
	__be16 opcode;		/* ARP Opcode	*/
	/* Above is exactly the same format as struct arphdr */

	__be64 s_uniq_id;	/* Sender's 64bit EUI			*/
	u8 max_rec;		/* Sender's max packet size		*/
	u8 sspd;		/* Sender's max speed			*/
	__be16 fifo_hi;		/* hi 16bits of sender's FIFO addr	*/
	__be32 fifo_lo;		/* lo 32bits of sender's FIFO addr	*/
	__be32 sip;		/* Sender's IP Address			*/
	__be32 tip;		/* IP Address of requested hw addr	*/
} __attribute__((packed));

/* This header format is specific to this driver implementation. */
#define FWNET_ALEN	8
#define FWNET_HLEN	10
struct fwnet_header {
	u8 h_dest[FWNET_ALEN];	/* destination address */
	__be16 h_proto;		/* packet type ID field */
} __attribute__((packed));

/* IPv4 and IPv6 encapsulation header */
struct rfc2734_header {
	u32 w0;
	u32 w1;
};

#define fwnet_get_hdr_lf(h)		(((h)->w0 & 0xc0000000) >> 30)
#define fwnet_get_hdr_ether_type(h)	(((h)->w0 & 0x0000ffff))
#define fwnet_get_hdr_dg_size(h)	(((h)->w0 & 0x0fff0000) >> 16)
#define fwnet_get_hdr_fg_off(h)		(((h)->w0 & 0x00000fff))
#define fwnet_get_hdr_dgl(h)		(((h)->w1 & 0xffff0000) >> 16)

#define fwnet_set_hdr_lf(lf)		((lf)  << 30)
#define fwnet_set_hdr_ether_type(et)	(et)
#define fwnet_set_hdr_dg_size(dgs)	((dgs) << 16)
#define fwnet_set_hdr_fg_off(fgo)	(fgo)

#define fwnet_set_hdr_dgl(dgl)		((dgl) << 16)

static inline void fwnet_make_uf_hdr(struct rfc2734_header *hdr,
		unsigned ether_type)
{
	hdr->w0 = fwnet_set_hdr_lf(RFC2374_HDR_UNFRAG)
		  | fwnet_set_hdr_ether_type(ether_type);
}

static inline void fwnet_make_ff_hdr(struct rfc2734_header *hdr,
		unsigned ether_type, unsigned dg_size, unsigned dgl)
{
	hdr->w0 = fwnet_set_hdr_lf(RFC2374_HDR_FIRSTFRAG)
		  | fwnet_set_hdr_dg_size(dg_size)
		  | fwnet_set_hdr_ether_type(ether_type);
	hdr->w1 = fwnet_set_hdr_dgl(dgl);
}

static inline void fwnet_make_sf_hdr(struct rfc2734_header *hdr,
		unsigned lf, unsigned dg_size, unsigned fg_off, unsigned dgl)
{
	hdr->w0 = fwnet_set_hdr_lf(lf)
		  | fwnet_set_hdr_dg_size(dg_size)
		  | fwnet_set_hdr_fg_off(fg_off);
	hdr->w1 = fwnet_set_hdr_dgl(dgl);
}

/* This list keeps track of what parts of the datagram have been filled in */
struct fwnet_fragment_info {
	struct list_head fi_link;
	u16 offset;
	u16 len;
};

struct fwnet_partial_datagram {
	struct list_head pd_link;
	struct list_head fi_list;
	struct sk_buff *skb;
	/* FIXME Why not use skb->data? */
	char *pbuf;
	u16 datagram_label;
	u16 ether_type;
	u16 datagram_size;
};

static DEFINE_MUTEX(fwnet_device_mutex);
static LIST_HEAD(fwnet_device_list);

struct fwnet_device {
	struct list_head dev_link;
	spinlock_t lock;
	enum {
		FWNET_BROADCAST_ERROR,
		FWNET_BROADCAST_RUNNING,
		FWNET_BROADCAST_STOPPED,
	} broadcast_state;
	struct fw_iso_context *broadcast_rcv_context;
	struct fw_iso_buffer broadcast_rcv_buffer;
	void **broadcast_rcv_buffer_ptrs;
	unsigned broadcast_rcv_next_ptr;
	unsigned num_broadcast_rcv_ptrs;
	unsigned rcv_buffer_size;
	/*
	 * This value is the maximum unfragmented datagram size that can be
	 * sent by the hardware.  It already has the GASP overhead and the
	 * unfragmented datagram header overhead calculated into it.
	 */
	unsigned broadcast_xmt_max_payload;
	u16 broadcast_xmt_datagramlabel;

	/*
	 * The CSR address that remote nodes must send datagrams to for us to
	 * receive them.
	 */
	struct fw_address_handler handler;
	u64 local_fifo;

	/* Number of tx datagrams that have been queued but not yet acked */
	int queued_datagrams;

	int peer_count;
	struct list_head peer_list;
	struct fw_card *card;
	struct net_device *netdev;
};

struct fwnet_peer {
	struct list_head peer_link;
	struct fwnet_device *dev;
	u64 guid;
	u64 fifo;

	/* guarded by dev->lock */
	struct list_head pd_list; /* received partial datagrams */
	unsigned pdg_size;        /* pd_list size */

	u16 datagram_label;       /* outgoing datagram label */
	u16 max_payload;          /* includes RFC2374_FRAG_HDR_SIZE overhead */