mpc.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/bitops.h>

/* We are an ethernet device */
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <net/sock.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>   /* for ip_fast_csum() */
#include <net/arp.h>
#include <net/dst.h>
#include <linux/proc_fs.h>

/* And atm device */
#include <linux/atmdev.h>
#include <linux/atmlec.h>
#include <linux/atmmpc.h>
/* Modular too */
#include <linux/config.h>
#include <linux/module.h>

#include "lec.h"
#include "mpc.h"
#include "resources.h"  /* for bind_vcc() */

/*
 * mpc.c: Implementation of MPOA client kernel part 
 */

#if 0
#define dprintk printk   /* debug */
#else
#define dprintk(format,args...)
#endif

#if 0
#define ddprintk printk  /* more debug */
#else
#define ddprintk(format,args...)
#endif



#define MPOA_TAG_LEN 4

/* mpc_daemon -> kernel */
static void MPOA_trigger_rcvd (struct k_message *msg, struct mpoa_client *mpc);
static void MPOA_res_reply_rcvd(struct k_message *msg, struct mpoa_client *mpc);
static void ingress_purge_rcvd(struct k_message *msg, struct mpoa_client *mpc);
static void egress_purge_rcvd(struct k_message *msg, struct mpoa_client *mpc);
static void mps_death(struct k_message *msg, struct mpoa_client *mpc);
static void clean_up(struct k_message *msg, struct mpoa_client *mpc, int action);
static void MPOA_cache_impos_rcvd(struct k_message *msg, struct mpoa_client *mpc);
static void set_mpc_ctrl_addr_rcvd(struct k_message *mesg, struct mpoa_client *mpc);
static void set_mps_mac_addr_rcvd(struct k_message *mesg, struct mpoa_client *mpc);

static uint8_t *copy_macs(struct mpoa_client *mpc, uint8_t *router_mac,
			  uint8_t *tlvs, uint8_t mps_macs, uint8_t device_type);
static void purge_egress_shortcut(struct atm_vcc *vcc, eg_cache_entry *entry);

static void send_set_mps_ctrl_addr(char *addr, struct mpoa_client *mpc);
static void mpoad_close(struct atm_vcc *vcc);
static int msg_from_mpoad(struct atm_vcc *vcc, struct sk_buff *skb);

static void mpc_push(struct atm_vcc *vcc, struct sk_buff *skb);
static int mpc_send_packet(struct sk_buff *skb, struct net_device *dev);
static int mpoa_event_listener(struct notifier_block *mpoa_notifier, unsigned long event, void *dev);
static void mpc_timer_refresh(void);
static void mpc_cache_check( unsigned long checking_time  );

static struct llc_snap_hdr llc_snap_mpoa_ctrl = {
	0xaa, 0xaa, 0x03,
	{0x00, 0x00, 0x5e},
	{0x00, 0x03}         /* For MPOA control PDUs */
};        
static struct llc_snap_hdr llc_snap_mpoa_data = {
	0xaa, 0xaa, 0x03,
	{0x00, 0x00, 0x00},
	{0x08, 0x00}         /* This is for IP PDUs only */
};        
static struct llc_snap_hdr llc_snap_mpoa_data_tagged = {
	0xaa, 0xaa, 0x03,
	{0x00, 0x00, 0x00},
	{0x88, 0x4c}         /* This is for tagged data PDUs */
};        

static struct notifier_block mpoa_notifier = {
	mpoa_event_listener,
	NULL,
	0
};

#ifdef CONFIG_PROC_FS
extern int mpc_proc_init(void);
extern void mpc_proc_clean(void);
#endif

struct mpoa_client *mpcs = NULL; /* FIXME */
static struct atm_mpoa_qos *qos_head = NULL;
static struct timer_list mpc_timer;


static struct mpoa_client *find_mpc_by_itfnum(int itf)
{
	struct mpoa_client *mpc;
	
	mpc = mpcs;  /* our global linked list */
	while (mpc != NULL) {
		if (mpc->dev_num == itf)
			return mpc;
		mpc = mpc->next;    
	}

	return NULL;   /* not found */
}

static struct mpoa_client *find_mpc_by_vcc(struct atm_vcc *vcc)
{
	struct mpoa_client *mpc;
	
	mpc = mpcs;  /* our global linked list */
	while (mpc != NULL) {
		if (mpc->mpoad_vcc == vcc)
			return mpc;
		mpc = mpc->next;
	}

	return NULL;   /* not found */
}

static struct mpoa_client *find_mpc_by_lec(struct net_device *dev)
{
	struct mpoa_client *mpc;
	
	mpc = mpcs;  /* our global linked list */
	while (mpc != NULL) {
		if (mpc->dev == dev)
			return mpc;
		mpc = mpc->next;
	}

	return NULL;   /* not found */
}

/*
 * Functions for managing QoS list
 */

/*
 * Overwrites the old entry or makes a new one.
 */
struct atm_mpoa_qos *atm_mpoa_add_qos(uint32_t dst_ip, struct atm_qos *qos)
{
	struct atm_mpoa_qos *entry;

	entry = atm_mpoa_search_qos(dst_ip);
	if (entry != NULL) {
		entry->qos = *qos;
		return entry;
	}

	entry = kmalloc(sizeof(struct atm_mpoa_qos), GFP_KERNEL);
	if (entry == NULL) {
		printk("mpoa: atm_mpoa_add_qos: out of memory\n");
		return entry;
	}

	entry->ipaddr = dst_ip;
	entry->qos = *qos;

	entry->next = qos_head;
	qos_head = entry;

	return entry;
}

struct atm_mpoa_qos *atm_mpoa_search_qos(uint32_t dst_ip)
{
	struct atm_mpoa_qos *qos;

	qos = qos_head;
	while( qos != NULL ){
		if(qos->ipaddr == dst_ip) {
			break;
		}
		qos = qos->next;
	}

	return qos;
}        

/*
 * Returns 0 for failure
 */
int atm_mpoa_delete_qos(struct atm_mpoa_qos *entry)
{

	struct atm_mpoa_qos *curr;

	if (entry == NULL) return 0;
	if (entry == qos_head) {
		qos_head = qos_head->next;
		kfree(entry);
		return 1;
	}

	curr = qos_head;
	while (curr != NULL) {
		if (curr->next == entry) {
			curr->next = entry->next;
			kfree(entry);
			return 1;
		}
		curr = curr->next;
	}

	return 0;
}

void atm_mpoa_disp_qos(char *page, int *len)
{

	unsigned char *ip;
	char ipaddr[16];
	struct atm_mpoa_qos *qos;

	qos = qos_head;
	*len += sprintf(page + *len, "QoS entries for shortcuts:\n");
	*len += sprintf(page + *len, "IP address\n  TX:max_pcr pcr     min_pcr max_cdv max_sdu\n  RX:max_pcr pcr     min_pcr max_cdv max_sdu\n");

	ipaddr[sizeof(ipaddr)-1] = '\0';
	while (qos != NULL) {
		ip = (unsigned char *)&qos->ipaddr;
		sprintf(ipaddr, "%u.%u.%u.%u", NIPQUAD(ip));
		*len += sprintf(page + *len, "%u.%u.%u.%u\n     %-7d %-7d %-7d %-7d %-7d\n     %-7d %-7d %-7d %-7d %-7d\n",
				NIPQUAD(ipaddr),
				qos->qos.txtp.max_pcr, qos->qos.txtp.pcr, qos->qos.txtp.min_pcr, qos->qos.txtp.max_cdv, qos->qos.txtp.max_sdu,
				qos->qos.rxtp.max_pcr, qos->qos.rxtp.pcr, qos->qos.rxtp.min_pcr, qos->qos.rxtp.max_cdv, qos->qos.rxtp.max_sdu);
		qos = qos->next;
	}
	
	return;
}

static struct net_device *find_lec_by_itfnum(int itf)
{
	extern struct atm_lane_ops atm_lane_ops; /* in common.c */
	
	if (atm_lane_ops.get_lecs == NULL)
		return NULL;

	return atm_lane_ops.get_lecs()[itf]; /* FIXME: something better */
}

static struct mpoa_client *alloc_mpc(void)
{
	struct mpoa_client *mpc;

	mpc = kmalloc(sizeof (struct mpoa_client), GFP_KERNEL);
	if (mpc == NULL)
		return NULL;
	memset(mpc, 0, sizeof(struct mpoa_client));
	mpc->ingress_lock = RW_LOCK_UNLOCKED;
	mpc->egress_lock  = RW_LOCK_UNLOCKED;
	mpc->next = mpcs;
	atm_mpoa_init_cache(mpc);

	mpc->parameters.mpc_p1 = MPC_P1;
	mpc->parameters.mpc_p2 = MPC_P2;
	memset(mpc->parameters.mpc_p3,0,sizeof(mpc->parameters.mpc_p3));
	mpc->parameters.mpc_p4 = MPC_P4;
	mpc->parameters.mpc_p5 = MPC_P5; 
	mpc->parameters.mpc_p6 = MPC_P6;
	
	mpcs = mpc;
	
	return mpc;
}

/*
 *
 * start_mpc() puts the MPC on line. All the packets destined
 * to the lec underneath us are now being monitored and 
 * shortcuts will be established.
 *
 */
static void start_mpc(struct mpoa_client *mpc, struct net_device *dev)
{
	
	dprintk("mpoa: (%s) start_mpc:\n", mpc->dev->name); 
	if (dev->hard_start_xmit == NULL) {
		printk("mpoa: (%s) start_mpc: dev->hard_start_xmit == NULL, not starting\n",
		       dev->name);
		return;
	}
	mpc->old_hard_start_xmit = dev->hard_start_xmit;
	dev->hard_start_xmit = mpc_send_packet;

	return;
}

static void stop_mpc(struct mpoa_client *mpc)
{
	
	dprintk("mpoa: (%s) stop_mpc:", mpc->dev->name); 

	/* Lets not nullify lec device's dev->hard_start_xmit */
	if (mpc->dev->hard_start_xmit != mpc_send_packet) {
		dprintk(" mpc already stopped, not fatal\n");
		return;
	}
	dprintk("\n");
	mpc->dev->hard_start_xmit = mpc->old_hard_start_xmit;
	mpc->old_hard_start_xmit = NULL;
	/* close_shortcuts(mpc);    ??? FIXME */
	
	return;
}

static const char * __attribute__ ((unused)) mpoa_device_type_string(char type)
{
	switch(type) {
	case NON_MPOA:
		return "non-MPOA device";
		break;
	case MPS:
		return "MPS";
		break;
	case MPC:
		return "MPC";
		break;
	case MPS_AND_MPC:
		return "both MPS and MPC";
		break;
	default:
		return "unspecified (non-MPOA) device";
		break;
	}

	return ""; /* not reached */
}

/*
 * lec device calls this via its dev->priv->lane2_ops->associate_indicator()
 * when it sees a TLV in LE_ARP packet.
 * We fill in the pointer above when we see a LANE2 lec initializing
 * See LANE2 spec 3.1.5
 *
 * Quite a big and ugly function but when you look at it
 * all it does is to try to locate and parse MPOA Device
 * Type TLV.
 * We give our lec a pointer to this function and when the
 * lec sees a TLV it uses the pointer to call this function.
 *
 */
static void lane2_assoc_ind(struct net_device *dev, uint8_t *mac_addr,
			    uint8_t *tlvs, uint32_t sizeoftlvs)
{
	uint32_t type;
	uint8_t length, mpoa_device_type, number_of_mps_macs;
	uint8_t *end_of_tlvs;
	struct mpoa_client *mpc;
	
	mpoa_device_type = number_of_mps_macs = 0; /* silence gcc */
	dprintk("mpoa: (%s) lane2_assoc_ind: received TLV(s), ", dev->name);
	dprintk("total length of all TLVs %d\n", sizeoftlvs);
	mpc = find_mpc_by_lec(dev); /* Sampo-Fix: moved here from below */
	if (mpc == NULL) {
		printk("mpoa: (%s) lane2_assoc_ind: no mpc\n", dev->name);
		return;
	}
	end_of_tlvs = tlvs + sizeoftlvs;
	while (end_of_tlvs - tlvs >= 5) {
		type = (tlvs[0] << 24) | (tlvs[1] << 16) | (tlvs[2] << 8) | tlvs[3];
		length = tlvs[4];
		tlvs += 5;
		dprintk("    type 0x%x length %02x\n", type, length);
		if (tlvs + length > end_of_tlvs) {
			printk("TLV value extends past its buffer, aborting parse\n");
			return;
		}
		
		if (type == 0) {
			printk("mpoa: (%s) lane2_assoc_ind: TLV type was 0, returning\n", dev->name);
			return;
		}

		if (type != TLV_MPOA_DEVICE_TYPE) {
			tlvs += length;
			continue;  /* skip other TLVs */
		}
		mpoa_device_type = *tlvs++;
		number_of_mps_macs = *tlvs++;
		dprintk("mpoa: (%s) MPOA device type '%s', ", dev->name, mpoa_device_type_string(mpoa_device_type));
		if (mpoa_device_type == MPS_AND_MPC &&
		    length < (42 + number_of_mps_macs*ETH_ALEN)) { /* :) */
			printk("\nmpoa: (%s) lane2_assoc_ind: short MPOA Device Type TLV\n",
			       dev->name);
			continue;
		}
		if ((mpoa_device_type == MPS || mpoa_device_type == MPC)
		    && length < 22 + number_of_mps_macs*ETH_ALEN) {
			printk("\nmpoa: (%s) lane2_assoc_ind: short MPOA Device Type TLV\n",
				dev->name);
			continue;
		}
		if (mpoa_device_type != MPS && mpoa_device_type != MPS_AND_MPC) {
			dprintk("ignoring non-MPS device\n");
			if (mpoa_device_type == MPC) tlvs += 20;
			continue;  /* we are only interested in MPSs */
		}
		if (number_of_mps_macs == 0 && mpoa_device_type == MPS_AND_MPC) {
			printk("\nmpoa: (%s) lane2_assoc_ind: MPS_AND_MPC has zero MACs\n", dev->name);
			continue;  /* someone should read the spec */
		}
		dprintk("this MPS has %d MAC addresses\n", number_of_mps_macs);
		
		/* ok, now we can go and tell our daemon the control address of MPS */
		send_set_mps_ctrl_addr(tlvs, mpc);
		
		tlvs = copy_macs(mpc, mac_addr, tlvs, number_of_mps_macs, mpoa_device_type);
		if (tlvs == NULL) return;
	}
	if (end_of_tlvs - tlvs != 0)
		printk("mpoa: (%s) lane2_assoc_ind: ignoring %d bytes of trailing TLV carbage\n",
		       dev->name, end_of_tlvs - tlvs);
	return;
}

/*
 * Store at least advertizing router's MAC address
 * plus the possible MAC address(es) to mpc->mps_macs.
 * For a freshly allocated MPOA client mpc->mps_macs == 0.
 */
static uint8_t *copy_macs(struct mpoa_client *mpc, uint8_t *router_mac,
			  uint8_t *tlvs, uint8_t mps_macs, uint8_t device_type)
{
	int num_macs;
	num_macs = (mps_macs > 1) ? mps_macs : 1;

	if (mpc->number_of_mps_macs != num_macs) { /* need to reallocate? */
		if (mpc->number_of_mps_macs != 0) kfree(mpc->mps_macs);
		mpc->number_of_mps_macs = 0;
		mpc->mps_macs = kmalloc(num_macs*ETH_ALEN, GFP_KERNEL);
		if (mpc->mps_macs == NULL) {
			printk("mpoa: (%s) copy_macs: out of mem\n", mpc->dev->name);
			return NULL;
		}
	}
	memcpy(mpc->mps_macs, router_mac, ETH_ALEN);
	tlvs += 20; if (device_type == MPS_AND_MPC) tlvs += 20;
	if (mps_macs > 0)
		memcpy(mpc->mps_macs, tlvs, mps_macs*ETH_ALEN);
	tlvs += mps_macs*ETH_ALEN;
	mpc->number_of_mps_macs = num_macs;

	return tlvs;
}

static int send_via_shortcut(struct sk_buff *skb, struct mpoa_client *mpc)
{
	in_cache_entry *entry;
	struct iphdr *iph;
	char *buff;
	uint32_t ipaddr = 0;

	static struct {
		struct llc_snap_hdr hdr;
		uint32_t tag;
	} tagged_llc_snap_hdr = {
		{0xaa, 0xaa, 0x03, {0x00, 0x00, 0x00}, {0x88, 0x4c}},
		0
	};

	buff = skb->data + mpc->dev->hard_header_len;
	iph = (struct iphdr *)buff;
	ipaddr = iph->daddr;

	ddprintk("mpoa: (%s) send_via_shortcut: ipaddr 0x%x\n", mpc->dev->name, ipaddr);        

	entry = mpc->in_ops->get(ipaddr, mpc);
	if (entry == NULL) {
		entry = mpc->in_ops->add_entry(ipaddr, mpc);
		if (entry != NULL) mpc->in_ops->put(entry);
		return 1;
	}
	if (mpc->in_ops->cache_hit(entry, mpc) != OPEN){   /* threshold not exceeded or VCC not ready */