arp.c

Minix比较全的源码

		memcpy (arp->a46_spa, &tpa, sizeof(ipaddr_t));
		arp->a46_tha= ce->ac_ethaddr;
		memcpy (arp->a46_tpa, &ce->ac_ipaddr, sizeof(ipaddr_t));

		assert(data->acc_linkC == 1);
		data->acc_ext_link= arp_port->ap_sendlist;
		arp_port->ap_sendlist= data; data= NULL;

		if (!(arp_port->ap_flags & APF_ARP_WR_IP))
			setup_write(arp_port);
	}
}

PRIVATE void client_reply (arp_port, ipaddr, ethaddr)
arp_port_t *arp_port;
ipaddr_t ipaddr;
ether_addr_t *ethaddr;
{
	(*arp_port->ap_arp_func)(arp_port->ap_ip_port, ipaddr, ethaddr);
}

PRIVATE arp_cache_t *find_cache_ent (arp_port, ipaddr)
arp_port_t *arp_port;
ipaddr_t ipaddr;
{
	arp_cache_t *ce;
	int i;
	unsigned hash;

	hash= (ipaddr >> 24) ^ (ipaddr >> 16) ^ (ipaddr >> 8) ^ ipaddr;
	hash &= ARP_HASH_MASK;

	ce= arp_hash[hash].ahe_row[0];
	if (ce && ce->ac_ipaddr == ipaddr && ce->ac_port == arp_port &&
		ce->ac_state != ACS_UNUSED)
	{
		return ce;
	}
	for (i= 1; i<ARP_HASH_WIDTH; i++)
	{
		ce= arp_hash[hash].ahe_row[i];
		if (!ce || ce->ac_ipaddr != ipaddr || ce->ac_port != arp_port
			|| ce->ac_state == ACS_UNUSED)
		{
			continue;
		}
		arp_hash[hash].ahe_row[i]= arp_hash[hash].ahe_row[0];
		arp_hash[hash].ahe_row[0]= ce;
		return ce;
	}

	for (i=0, ce= arp_cache; i<arp_cache_nr; i++, ce++)
	{
		if (ce->ac_state != ACS_UNUSED &&
			ce->ac_port == arp_port &&
			ce->ac_ipaddr == ipaddr)
		{
			for (i= ARP_HASH_WIDTH-1; i>0; i--)
			{
				arp_hash[hash].ahe_row[i]=
					arp_hash[hash].ahe_row[i-1];
			}
			assert(i == 0);
			arp_hash[hash].ahe_row[0]= ce;
			return ce;
		}
	}
	return NULL;
}

PRIVATE arp_cache_t *alloc_cache_ent(flags)
int flags;
{
	arp_cache_t *cache, *old;
	int i;

	old= NULL;
	for (i=0, cache= arp_cache; i<arp_cache_nr; i++, cache++)
	{
		if (cache->ac_state == ACS_UNUSED)
		{
			old= cache;
			break;
		}
		if (cache->ac_state == ACS_INCOMPLETE)
			continue;
		if (cache->ac_flags & ACF_PERM)
			continue;
		if (!old || cache->ac_lastuse < old->ac_lastuse)
			old= cache;
	}
	assert(old);

	if (!flags)
		return old;

	/* Get next permanent entry */
	for (i=0, cache= arp_cache; i<arp_cache_nr; i++, cache++)
	{
		if (cache->ac_state == ACS_UNUSED)
			break;
		if (cache->ac_flags & ACF_PERM)
			continue;
		break;
	}
	if (i >= arp_cache_nr/2)
		return NULL; /* Too many entries */
	if (cache != old)
	{
		assert(old > cache);
		*old= *cache;
		old= cache;
	}

	if (!(flags & ACF_PUB))
		return old;

	/* Get first nonpublished entry */
	for (i=0, cache= arp_cache; i<arp_cache_nr; i++, cache++)
	{
		if (cache->ac_state == ACS_UNUSED)
			break;
		if (cache->ac_flags & ACF_PUB)
			continue;
		break;
	}
	if (cache != old)
	{
		assert(old > cache);
		*old= *cache;
		old= cache;
	}
	return old;
}

PUBLIC void arp_set_ipaddr (eth_port, ipaddr)
int eth_port;
ipaddr_t ipaddr;
{
	arp_port_t *arp_port;

	if (eth_port < 0 || eth_port >= eth_conf_nr)
		return;
	arp_port= &arp_port_table[eth_port];

	arp_port->ap_ipaddr= ipaddr;
	arp_port->ap_flags |= APF_INADDR_SET;
	arp_port->ap_flags &= ~APF_SUSPEND;
	if (arp_port->ap_state == APS_GETADDR)
		arp_main(arp_port);
}

PUBLIC int arp_set_cb(eth_port, ip_port, arp_func)
int eth_port;
int ip_port;
arp_func_t arp_func;
{
	int i;
	arp_port_t *arp_port;

	assert(eth_port >= 0);
	if (eth_port >= eth_conf_nr)
		return ENXIO;

	arp_port= &arp_port_table[eth_port];
	arp_port->ap_eth_port= eth_port;
	arp_port->ap_ip_port= ip_port;
	arp_port->ap_state= APS_INITIAL;
	arp_port->ap_flags= APF_EMPTY;
	arp_port->ap_arp_func= arp_func;
	arp_port->ap_sendpkt= NULL;
	arp_port->ap_sendlist= NULL;
	arp_port->ap_reclist= NULL;
	for (i= 0; i<AP_REQ_NR; i++)
		arp_port->ap_req[i].ar_entry= -1;
	ev_init(&arp_port->ap_event);

	arp_main(arp_port);

	return NW_OK;
}

PUBLIC int arp_ip_eth (eth_port, ipaddr, ethaddr)
int eth_port;
ipaddr_t ipaddr;
ether_addr_t *ethaddr;
{
	int i, ref;
	arp_port_t *arp_port;
	struct arp_req *reqp;
	arp_cache_t *ce;
	time_t curr_time;

	assert(eth_port >= 0 && eth_port < eth_conf_nr);
	arp_port= &arp_port_table[eth_port];
	assert(arp_port->ap_state == APS_ARPMAIN ||
		(printf("arp[%d]: ap_state= %d\n", arp_port-arp_port_table,
		arp_port->ap_state), 0));

	curr_time= get_time();

	ce= find_cache_ent (arp_port, ipaddr);
	if (ce && ce->ac_expire < curr_time)
	{
		assert(ce->ac_state != ACS_INCOMPLETE);

		/* Check whether there is enough space for an ARP
		 * request or not.
		 */
		for (i= 0, reqp= arp_port->ap_req; i<AP_REQ_NR; i++, reqp++)
		{
			if (reqp->ar_entry < 0)
				break;
		}
		if (i < AP_REQ_NR)
		{
			/* Okay, expire this entry. */
			ce->ac_state= ACS_UNUSED;
			ce= NULL;
		}
		else
		{
			/* Continue using this entry for a while */
			printf("arp[%d]: Overloaded! Keeping entry for ",
				arp_port-arp_port_table);
			writeIpAddr(ipaddr);
			printf("\n");
			ce->ac_expire= curr_time+ARP_NOTRCH_EXP_TIME;
		}
	}
	if (ce)
	{
		/* Found an entry. This entry should be valid, unreachable
		 * or incomplete.
		 */
		ce->ac_lastuse= curr_time;
		if (ce->ac_state == ACS_VALID)
		{
			*ethaddr= ce->ac_ethaddr;
			return NW_OK;
		}
		if (ce->ac_state == ACS_UNREACHABLE)
			return EDSTNOTRCH;
		assert(ce->ac_state == ACS_INCOMPLETE);

		return NW_SUSPEND;
	}

	/* Find an empty slot for an ARP request */
	for (i= 0, reqp= arp_port->ap_req; i<AP_REQ_NR; i++, reqp++)
	{
		if (reqp->ar_entry < 0)
			break;
	}
	if (i >= AP_REQ_NR)
	{
		/* We should be able to report that this ARP request
		 * cannot be accepted. At the moment we just return SUSPEND.
		 */
		return NW_SUSPEND;
	}
	ref= (eth_port*AP_REQ_NR + i);

	ce= alloc_cache_ent(ACF_EMPTY);
	ce->ac_flags= 0;
	ce->ac_state= ACS_INCOMPLETE;
	ce->ac_ipaddr= ipaddr;
	ce->ac_port= arp_port;
	ce->ac_expire= curr_time+ARP_EXP_TIME;
	ce->ac_lastuse= curr_time;

	reqp->ar_entry= ce-arp_cache;
	reqp->ar_req_count= -1;

	/* Send the first packet by expiring the timer */
	clck_timer(&reqp->ar_timer, 1, arp_timeout, ref);

	return NW_SUSPEND;
}

PUBLIC int arp_ioctl (eth_port, fd, req, get_userdata, put_userdata)
int eth_port;
int fd;
ioreq_t req;
get_userdata_t get_userdata;
put_userdata_t put_userdata;
{
	arp_port_t *arp_port;
	arp_cache_t *ce, *cache;
	acc_t *data;
	nwio_arp_t *arp_iop;
	int entno, result, ac_flags;
	u32_t flags;
	ipaddr_t ipaddr;
	time_t curr_time;

	assert(eth_port >= 0 && eth_port < eth_conf_nr);
	arp_port= &arp_port_table[eth_port];
	assert(arp_port->ap_state == APS_ARPMAIN ||
		(printf("arp[%d]: ap_state= %d\n", arp_port-arp_port_table,
		arp_port->ap_state), 0));

	switch(req)
	{
	case NWIOARPGIP:
		data= (*get_userdata)(fd, 0, sizeof(*arp_iop), TRUE);
		if (data == NULL)
			return EFAULT;
		data= bf_packIffLess(data, sizeof(*arp_iop));
		arp_iop= (nwio_arp_t *)ptr2acc_data(data);
		ipaddr= arp_iop->nwa_ipaddr;
		ce= NULL;	/* lint */
		for (entno= 0; entno < arp_cache_nr; entno++)
		{
			ce= &arp_cache[entno];
			if (ce->ac_state == ACS_UNUSED ||
				ce->ac_port != arp_port)
			{
				continue;
			}
			if (ce->ac_ipaddr == ipaddr)
				break;
		}
		if (entno == arp_cache_nr)
		{
			/* Also report the address of this interface */
			if (ipaddr != arp_port->ap_ipaddr)
			{
				bf_afree(data);
				return ENOENT;
			}
			arp_iop->nwa_entno= arp_cache_nr;
			arp_iop->nwa_ipaddr= ipaddr;
			arp_iop->nwa_ethaddr= arp_port->ap_ethaddr;
			arp_iop->nwa_flags= NWAF_PERM | NWAF_PUB;
		}
		else
		{
			arp_iop->nwa_entno= entno+1;
			arp_iop->nwa_ipaddr= ce->ac_ipaddr;
			arp_iop->nwa_ethaddr= ce->ac_ethaddr;
			arp_iop->nwa_flags= 0;
			if (ce->ac_state == ACS_INCOMPLETE)
				arp_iop->nwa_flags |= NWAF_INCOMPLETE;
			if (ce->ac_state == ACS_UNREACHABLE)
				arp_iop->nwa_flags |= NWAF_DEAD;
			if (ce->ac_flags & ACF_PERM)
				arp_iop->nwa_flags |= NWAF_PERM;
			if (ce->ac_flags & ACF_PUB)
				arp_iop->nwa_flags |= NWAF_PUB;
		}

		result= (*put_userdata)(fd, 0, data, TRUE);
		return result;

	case NWIOARPGNEXT:
		data= (*get_userdata)(fd, 0, sizeof(*arp_iop), TRUE);
		if (data == NULL)
			return EFAULT;
		data= bf_packIffLess(data, sizeof(*arp_iop));
		arp_iop= (nwio_arp_t *)ptr2acc_data(data);
		entno= arp_iop->nwa_entno;
		if (entno < 0)
			entno= 0;
		ce= NULL;	/* lint */
		for (; entno < arp_cache_nr; entno++)
		{
			ce= &arp_cache[entno];
			if (ce->ac_state == ACS_UNUSED ||
				ce->ac_port != arp_port)
			{
				continue;
			}
			break;
		}
		if (entno == arp_cache_nr)
		{
			bf_afree(data);
			return ENOENT;
		}
		arp_iop->nwa_entno= entno+1;
		arp_iop->nwa_ipaddr= ce->ac_ipaddr;
		arp_iop->nwa_ethaddr= ce->ac_ethaddr;
		arp_iop->nwa_flags= 0;
		if (ce->ac_state == ACS_INCOMPLETE)
			arp_iop->nwa_flags |= NWAF_INCOMPLETE;
		if (ce->ac_state == ACS_UNREACHABLE)
			arp_iop->nwa_flags |= NWAF_DEAD;
		if (ce->ac_flags & ACF_PERM)
			arp_iop->nwa_flags |= NWAF_PERM;
		if (ce->ac_flags & ACF_PUB)
			arp_iop->nwa_flags |= NWAF_PUB;

		result= (*put_userdata)(fd, 0, data, TRUE);
		return result;

	case NWIOARPSIP:
		data= (*get_userdata)(fd, 0, sizeof(*arp_iop), TRUE);
		if (data == NULL)
			return EFAULT;
		data= bf_packIffLess(data, sizeof(*arp_iop));
		arp_iop= (nwio_arp_t *)ptr2acc_data(data);
		ipaddr= arp_iop->nwa_ipaddr;
		if (find_cache_ent(arp_port, ipaddr))
		{
			bf_afree(data);
			return EEXIST;
		}

		flags= arp_iop->nwa_flags;
		ac_flags= ACF_EMPTY;
		if (flags & NWAF_PERM)
			ac_flags |= ACF_PERM;
		if (flags & NWAF_PUB)
			ac_flags |= ACF_PUB|ACF_PERM;

		/* Allocate a cache entry */
		ce= alloc_cache_ent(ac_flags);
		if (ce == NULL)
		{
			bf_afree(data);
			return ENOMEM;
		}

		ce->ac_flags= ac_flags;
		ce->ac_state= ACS_VALID;
		ce->ac_ethaddr= arp_iop->nwa_ethaddr;
		ce->ac_ipaddr= arp_iop->nwa_ipaddr;
		ce->ac_port= arp_port;

		curr_time= get_time();
		ce->ac_expire= curr_time+ARP_EXP_TIME;
		ce->ac_lastuse= curr_time;

		bf_afree(data);
		return 0;

	case NWIOARPDIP:
		data= (*get_userdata)(fd, 0, sizeof(*arp_iop), TRUE);
		if (data == NULL)
			return EFAULT;
		data= bf_packIffLess(data, sizeof(*arp_iop));
		arp_iop= (nwio_arp_t *)ptr2acc_data(data);
		ipaddr= arp_iop->nwa_ipaddr;
		bf_afree(data); data= NULL;
		ce= find_cache_ent(arp_port, ipaddr);
		if (!ce)
			return ENOENT;
		if (ce->ac_state == ACS_INCOMPLETE)
			return EINVAL;

		ac_flags= ce->ac_flags;
		if (ac_flags & ACF_PUB)
		{
			/* Make sure entry is at the end of published
			 * entries.
			 */
			for (entno= 0, cache= arp_cache;
				entno<arp_cache_nr; entno++, cache++)
			{
				if (cache->ac_state == ACS_UNUSED)
					break;
				if (cache->ac_flags & ACF_PUB)
					continue;
				break;
			}
			assert(cache > arp_cache);
			cache--;
			if (cache != ce)
			{
				assert(cache > ce);
				*ce= *cache;
				ce= cache;
			}
		}
		if (ac_flags & ACF_PERM)
		{
			/* Make sure entry is at the end of permanent
			 * entries.
			 */
			for (entno= 0, cache= arp_cache;
				entno<arp_cache_nr; entno++, cache++)
			{
				if (cache->ac_state == ACS_UNUSED)
					break;
				if (cache->ac_flags & ACF_PERM)
					continue;
				break;
			}
			assert(cache > arp_cache);
			cache--;
			if (cache != ce)
			{
				assert(cache > ce);
				*ce= *cache;
				ce= cache;
			}
		}

		/* Clear entry */
		ce->ac_state= ACS_UNUSED;

		return 0;

	default:
		ip_panic(("arp_ioctl: unknown request 0x%lx",
			(unsigned long)req));
	}
	return 0;
}

PRIVATE void arp_timeout (ref, timer)
int ref;
timer_t *timer;
{
	int i, port, reqind, acind;
	arp_port_t *arp_port;
	arp_cache_t *ce;
	struct arp_req *reqp;
	time_t curr_time;
	acc_t *data;
	arp46_t *arp;
	u16_t *p;

	port= ref / AP_REQ_NR;
	reqind= ref % AP_REQ_NR;

	assert(port >= 0 && port <eth_conf_nr);
	arp_port= &arp_port_table[port];

	reqp= &arp_port->ap_req[reqind];
	assert (timer == &reqp->ar_timer);

	acind= reqp->ar_entry;

	assert(acind >= 0 && acind < arp_cache_nr);
	ce= &arp_cache[acind];

	assert(ce->ac_port == arp_port);
	assert(ce->ac_state == ACS_INCOMPLETE);

	if (++reqp->ar_req_count >= MAX_ARP_RETRIES)
	{
		curr_time= get_time();
		ce->ac_state= ACS_UNREACHABLE;
		ce->ac_expire= curr_time+ ARP_NOTRCH_EXP_TIME;
		ce->ac_lastuse= curr_time;

		clck_untimer(&reqp->ar_timer);
		reqp->ar_entry= -1;
		client_reply(arp_port, ce->ac_ipaddr, NULL);
		return;
	}

	data= bf_memreq(sizeof(arp46_t));
	arp= (arp46_t *)ptr2acc_data(data);

	/* Clear padding */
	assert(sizeof(arp->a46_data.a46_dummy) % sizeof(*p) == 0);
	for (i= 0, p= (u16_t *)arp->a46_data.a46_dummy;
		i < sizeof(arp->a46_data.a46_dummy)/sizeof(*p);
		i++, p++)
	{
		*p= 0xdead;
	}

	arp->a46_dstaddr.ea_addr[0]= 0xff;
	arp->a46_dstaddr.ea_addr[1]= 0xff;
	arp->a46_dstaddr.ea_addr[2]= 0xff;
	arp->a46_dstaddr.ea_addr[3]= 0xff;
	arp->a46_dstaddr.ea_addr[4]= 0xff;
	arp->a46_dstaddr.ea_addr[5]= 0xff;
	arp->a46_hdr= HTONS(ARP_ETHERNET);
	arp->a46_pro= HTONS(ETH_IP_PROTO);
	arp->a46_hln= 6;
	arp->a46_pln= 4;
	arp->a46_op= HTONS(ARP_REQUEST);
	arp->a46_sha= arp_port->ap_ethaddr;
	memcpy (arp->a46_spa, &arp_port->ap_ipaddr, sizeof(ipaddr_t));
	memset(&arp->a46_tha, '\0', sizeof(ether_addr_t));
	memcpy (arp->a46_tpa, &ce->ac_ipaddr, sizeof(ipaddr_t));

	assert(data->acc_linkC == 1);
	data->acc_ext_link= arp_port->ap_sendlist;
	arp_port->ap_sendlist= data; data= NULL;

	if (!(arp_port->ap_flags & APF_ARP_WR_IP))
		setup_write(arp_port);

	clck_timer(&reqp->ar_timer, get_time() + ARP_TIMEOUT,
		arp_timeout, ref);
}

PRIVATE void arp_buffree(priority)
int priority;
{
	int i;
	acc_t *pack, *next_pack;
	arp_port_t *arp_port;

	for (i= 0, arp_port= arp_port_table; i<eth_conf_nr; i++, arp_port++)
	{
		if (priority == ARP_PRI_REC)
		{
			next_pack= arp_port->ap_reclist;
			while(next_pack && next_pack->acc_ext_link)
			{
				pack= next_pack;
				next_pack= pack->acc_ext_link;
				bf_afree(pack);
			}
			if (next_pack)
			{
				if (ev_in_queue(&arp_port->ap_event))
				{
					DBLOCK(1, printf(
			"not freeing ap_reclist, ap_event enqueued\n"));
				}
				else
				{
					bf_afree(next_pack);
					next_pack= NULL;
				}
			}
			arp_port->ap_reclist= next_pack;
		}
		if (priority == ARP_PRI_SEND)
		{
			next_pack= arp_port->ap_sendlist;
			while(next_pack && next_pack->acc_ext_link)
			{
				pack= next_pack;
				next_pack= pack->acc_ext_link;
				bf_afree(pack);
			}
			if (next_pack)
			{
				if (ev_in_queue(&arp_port->ap_event))
				{
					DBLOCK(1, printf(
			"not freeing ap_sendlist, ap_event enqueued\n"));
				}
				else
				{
					bf_afree(next_pack);
					next_pack= NULL;
				}
			}
			arp_port->ap_sendlist= next_pack;
		}
	}
}

#ifdef BUF_CONSISTENCY_CHECK
PRIVATE void arp_bufcheck()
{
	int i;
	arp_port_t *arp_port;
	acc_t *pack;

	for (i= 0, arp_port= arp_port_table; i<eth_conf_nr; i++, arp_port++)
	{
		for (pack= arp_port->ap_reclist; pack;
			pack= pack->acc_ext_link)
		{
			bf_check_acc(pack);
		}
		for (pack= arp_port->ap_sendlist; pack;
			pack= pack->acc_ext_link)
		{
			bf_check_acc(pack);
		}
	}
}
#endif /* BUF_CONSISTENCY_CHECK */

/*
 * $PchId: arp.c,v 1.22 2005/06/28 14:15:06 philip Exp $
 */