dn_nsp_in.c

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	kfree_skb(skb);
}

/*
 * disc_conf messages are also called no_resources or no_link
 * messages depending upon the "reason" field.
 */
static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = &sk->protinfo.dn;
	unsigned short reason;

	if (skb->len != 2)
		goto out;

	reason = dn_ntohs(*(__u16 *)skb->data);

	sk->state = TCP_CLOSE;

	switch(scp->state) {
		case DN_CI:
			scp->state = DN_NR;
			break;
		case DN_DR:
			if (reason == NSP_REASON_DC)
				scp->state = DN_DRC;
			if (reason == NSP_REASON_NL)
				scp->state = DN_CN;
			break;
		case DN_DI:
			scp->state = DN_DIC;
			break;
		case DN_RUN:
			sk->shutdown |= SHUTDOWN_MASK;
		case DN_CC:
			scp->state = DN_CN;
	}

	if (!sk->dead) {
		if (sk->socket->state != SS_UNCONNECTED)
			sk->socket->state = SS_DISCONNECTING;
		sk->state_change(sk);
	}

	scp->persist_fxn = dn_destroy_timer;
	scp->persist = dn_nsp_persist(sk);

out:
	kfree_skb(skb);
}

static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
{
	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
	unsigned short segnum;
	unsigned char lsflags;
	char fcval;

	if (skb->len != 4)
		goto out;

	cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
	skb_pull(skb, 2);
	lsflags = *(unsigned char *)skb->data;
	skb_pull(skb, 1);
	fcval = *(char *)skb->data;

	if (lsflags & 0xf0)
		goto out;

	if (((sk->protinfo.dn.numoth_rcv + 1) & 0x0FFF) == (segnum & 0x0FFF)) {
        	sk->protinfo.dn.numoth_rcv += 1;        
                switch(lsflags & 0x03) {
                	case 0x00:      
                        	break;
                        case 0x01:      
                                sk->protinfo.dn.flowrem_sw = DN_DONTSEND;
                                break;
                        case 0x02:      
                                sk->protinfo.dn.flowrem_sw = DN_SEND;
				dn_nsp_output(sk);
				if (!sk->dead)
					sk->state_change(sk);
                }
                
        }

	dn_nsp_send_oth_ack(sk);

out:
	kfree_skb(skb);
}

/*
 * Copy of sock_queue_rcv_skb (from sock.h) without
 * bh_lock_sock() (its already held when this is called) which
 * also allows data and other data to be queued to a socket.
 */
static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
{
#ifdef CONFIG_FILTER
	struct sk_filter *filter;
#endif

        /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
           number of warnings when compiling with -W --ANK
         */
        if (atomic_read(&sk->rmem_alloc) + skb->truesize >= (unsigned)sk->rcvbuf
)
                return -ENOMEM;

#ifdef CONFIG_FILTER
        if (sk->filter) {
		int err = 0;
                if ((filter = sk->filter) != NULL && sk_filter(skb, sk->filter))
                        err = -EPERM;  /* Toss packet */
		if (err)
			return err;
        }
#endif /* CONFIG_FILTER */

        skb_set_owner_r(skb, sk);
        skb_queue_tail(queue, skb);

	/* This code only runs from BH or BH protected context.
	 * Therefore the plain read_lock is ok here. -DaveM
	 */
	read_lock(&sk->callback_lock);
        if (!sk->dead) {
		struct socket *sock = sk->socket;
		wake_up_interruptible(sk->sleep);
		if (sock && sock->fasync_list &&
		    !test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
			__kill_fasync(sock->fasync_list, sig, 
				    (sig == SIGURG) ? POLL_PRI : POLL_IN);
	}
	read_unlock(&sk->callback_lock);

        return 0;
}

static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = &sk->protinfo.dn;
	unsigned short segnum;
	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
	int queued = 0;

	if (skb->len < 2)
		goto out;

	cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
	skb_pull(skb, 2);

	if (((sk->protinfo.dn.numoth_rcv + 1) & 0x0fff) == (segnum & 0x0fff)) {

		if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
			sk->protinfo.dn.numoth_rcv++;
			scp->other_report = 0;
			queued = 1;
		}
	}

	dn_nsp_send_oth_ack(sk);
out:
	if (!queued)
		kfree_skb(skb);
}

static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
{
	int queued = 0;
	unsigned short segnum;
	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
	struct dn_scp *scp = &sk->protinfo.dn;

	if (skb->len < 2)
		goto out;

	cb->segnum = segnum = dn_ntohs(*(__u16 *)skb->data);
	skb_pull(skb, 2);

	if (((sk->protinfo.dn.numdat_rcv + 1) & 0x0FFF) == 
                     (segnum & 0x0FFF)) {

                if (dn_queue_skb(sk, skb, SIGIO, &sk->receive_queue) == 0) {
			sk->protinfo.dn.numdat_rcv++;
                	queued = 1;
                }

		if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
			scp->flowloc_sw = DN_DONTSEND;
			dn_nsp_send_lnk(sk, DN_DONTSEND);
		}
        }

	dn_nsp_send_data_ack(sk);
out:
	if (!queued)
		kfree_skb(skb);
}

/*
 * If one of our conninit messages is returned, this function
 * deals with it. It puts the socket into the NO_COMMUNICATION
 * state.
 */
static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = &sk->protinfo.dn;

	if (scp->state == DN_CI) {
		scp->state = DN_NC;
		sk->state = TCP_CLOSE;
		if (!sk->dead)
			sk->state_change(sk);
	}

	kfree_skb(skb);
}

static void dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
{
	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;

	if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
		switch(cb->nsp_flags & 0x70) {
			case 0x10:
			case 0x60: /* (Retransmitted) Connect Init */
				dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
				break;
			case 0x20: /* Connect Confirm */
				dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
				break;
		}
	}

	kfree_skb(skb);
}

static int dn_nsp_rx_packet(struct sk_buff *skb)
{
	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
	struct sock *sk = NULL;
	unsigned char *ptr = (unsigned char *)skb->data;
	unsigned short reason = NSP_REASON_NL;

	skb->h.raw    = skb->data;
	cb->nsp_flags = *ptr++;

	if (decnet_debug_level & 2)
		printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);

	if (skb->len < 2) 
		goto free_out;

	if (cb->nsp_flags & 0x83) 
		goto free_out;

	/*
	 * Returned packets...
	 * Swap src & dst and look up in the normal way.
	 */
	if (cb->rt_flags & DN_RT_F_RTS) {
		unsigned short tmp = cb->dst_port;
		cb->dst_port = cb->src_port;
		cb->src_port = tmp;
		tmp = cb->dst;
		cb->dst = cb->src;
		cb->src = tmp;
		sk = dn_find_by_skb(skb);
		goto got_it;
	}

	/*
	 * Filter out conninits and useless packet types
	 */
	if ((cb->nsp_flags & 0x0c) == 0x08) {
		switch(cb->nsp_flags & 0x70) {
			case 0x00: /* NOP */
			case 0x70: /* Reserved */
			case 0x50: /* Reserved, Phase II node init */
				goto free_out;
			case 0x10:
			case 0x60:
				sk = dn_find_listener(skb, &reason);
				goto got_it;
		}
	}

	if (skb->len < 3)
		goto free_out;

	/*
	 * Grab the destination address.
	 */
	cb->dst_port = *(unsigned short *)ptr;
	cb->src_port = 0;
	ptr += 2;

	/*
	 * If not a connack, grab the source address too.
	 */
	if (skb->len >= 5) {
		cb->src_port = *(unsigned short *)ptr;
		ptr += 2;
		skb_pull(skb, 5);
	}

	/*
	 * Find the socket to which this skb is destined.
	 */
	sk = dn_find_by_skb(skb);
got_it:
	if (sk != NULL) {
		struct dn_scp *scp = &sk->protinfo.dn;
		int ret;

		/* Reset backoff */
		scp->nsp_rxtshift = 0;

		bh_lock_sock(sk);
		ret = 0;
		if (sk->lock.users == 0)
			ret = dn_nsp_backlog_rcv(sk, skb);
		else
			sk_add_backlog(sk, skb);
		bh_unlock_sock(sk);
		sock_put(sk);

		return ret;
	}

	dn_nsp_no_socket(skb, reason);
	return 1;

free_out:
	kfree_skb(skb);
	return 0;
}

int dn_nsp_rx(struct sk_buff *skb)
{
	return NF_HOOK(PF_DECnet, NF_DN_LOCAL_IN, skb, skb->dev, NULL, dn_nsp_rx_packet);
}

/*
 * This is the main receive routine for sockets. It is called
 * from the above when the socket is not busy, and also from
 * sock_release() when there is a backlog queued up.
 */
int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
	struct dn_scp *scp = &sk->protinfo.dn;
	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;

	if (cb->rt_flags & DN_RT_F_RTS) {
		dn_returned_conn_init(sk, skb);
		return 0;
	}

	/*
	 * Control packet.
	 */
	if ((cb->nsp_flags & 0x0c) == 0x08) {
		switch(cb->nsp_flags & 0x70) {
			case 0x10:
			case 0x60:
				dn_nsp_conn_init(sk, skb);
				break;
			case 0x20:
				dn_nsp_conn_conf(sk, skb);
				break;
			case 0x30:
				dn_nsp_disc_init(sk, skb);
				break;
			case 0x40:      
				dn_nsp_disc_conf(sk, skb);
				break;
		}

	} else if (cb->nsp_flags == 0x24) {
		/*
		 * Special for connacks, 'cos they don't have
		 * ack data or ack otherdata info.
		 */
		dn_nsp_conn_ack(sk, skb);
	} else {
		int other = 1;

		/* both data and ack frames can kick a CC socket into RUN */
		if ((scp->state == DN_CC) && !sk->dead) {
			scp->state = DN_RUN;
			sk->state = TCP_ESTABLISHED;
			sk->state_change(sk);
		}

		if ((cb->nsp_flags & 0x1c) == 0)
			other = 0;
		if (cb->nsp_flags == 0x04)
			other = 0;

		/*
		 * Read out ack data here, this applies equally
		 * to data, other data, link serivce and both
		 * ack data and ack otherdata.
		 */
		dn_process_ack(sk, skb, other);

		/*
		 * If we've some sort of data here then call a
		 * suitable routine for dealing with it, otherwise
		 * the packet is an ack and can be discarded.
		 */
		if ((cb->nsp_flags & 0x0c) == 0) {

			if (scp->state != DN_RUN)
				goto free_out;

			switch(cb->nsp_flags) {
				case 0x10: /* LS */
					dn_nsp_linkservice(sk, skb);
					break;
				case 0x30: /* OD */
					dn_nsp_otherdata(sk, skb);
					break;
				default:
					dn_nsp_data(sk, skb);
			}

		} else { /* Ack, chuck it out here */
free_out:
			kfree_skb(skb);
		}
	}

	return 0;
}