[deliverable/linux.git] / net / dccp / input.c

/*
 *  net/dccp/input.c
 * 
 *  An implementation of the DCCP protocol
 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#include <linux/config.h>
#include <linux/dccp.h>
#include <linux/skbuff.h>

#include <net/sock.h>

#include "ackvec.h"
#include "ccid.h"
#include "dccp.h"

static void dccp_fin(struct sock *sk, struct sk_buff *skb)
{
	sk->sk_shutdown |= RCV_SHUTDOWN;
	sock_set_flag(sk, SOCK_DONE);
	__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
	__skb_queue_tail(&sk->sk_receive_queue, skb);
	skb_set_owner_r(skb, sk);
	sk->sk_data_ready(sk, 0);
}

static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
{
	dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
	dccp_fin(sk, skb);
	dccp_set_state(sk, DCCP_CLOSED);
	sk_wake_async(sk, 1, POLL_HUP);
}

static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
{
	/*
	 *   Step 7: Check for unexpected packet types
	 *      If (S.is_server and P.type == CloseReq)
	 *	  Send Sync packet acknowledging P.seqno
	 *	  Drop packet and return
	 */
	if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
		return;
	}

	if (sk->sk_state != DCCP_CLOSING)
		dccp_set_state(sk, DCCP_CLOSING);
	dccp_send_close(sk, 0);
}

static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
{
	struct dccp_sock *dp = dccp_sk(sk);

	if (dp->dccps_options.dccpo_send_ack_vector)
		dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
					    DCCP_SKB_CB(skb)->dccpd_ack_seq);
}

static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
{
	const struct dccp_hdr *dh = dccp_hdr(skb);
	struct dccp_sock *dp = dccp_sk(sk);
	u64 lswl, lawl;

	/*
	 *   Step 5: Prepare sequence numbers for Sync
	 *     If P.type == Sync or P.type == SyncAck,
	 *	  If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
	 *	     / * P is valid, so update sequence number variables
	 *		 accordingly.  After this update, P will pass the tests
	 *		 in Step 6.  A SyncAck is generated if necessary in
	 *		 Step 15 * /
	 *	     Update S.GSR, S.SWL, S.SWH
	 *	  Otherwise,
	 *	     Drop packet and return
	 */
	if (dh->dccph_type == DCCP_PKT_SYNC || 
	    dh->dccph_type == DCCP_PKT_SYNCACK) {
		if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
			      dp->dccps_awl, dp->dccps_awh) &&
		    !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
			dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
		else
			return -1;
	}
	
	/*
	 *   Step 6: Check sequence numbers
	 *      Let LSWL = S.SWL and LAWL = S.AWL
	 *      If P.type == CloseReq or P.type == Close or P.type == Reset,
	 *	  LSWL := S.GSR + 1, LAWL := S.GAR
	 *      If LSWL <= P.seqno <= S.SWH
	 *	     and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
	 *	  Update S.GSR, S.SWL, S.SWH
	 *	  If P.type != Sync,
	 *	     Update S.GAR
	 *      Otherwise,
	 *	  Send Sync packet acknowledging P.seqno
	 *	  Drop packet and return
	 */
	lswl = dp->dccps_swl;
	lawl = dp->dccps_awl;

	if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
	    dh->dccph_type == DCCP_PKT_CLOSE ||
	    dh->dccph_type == DCCP_PKT_RESET) {
		lswl = dp->dccps_gsr;
		dccp_inc_seqno(&lswl);
		lawl = dp->dccps_gar;
	}

	if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
	    (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
	     between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
		       lawl, dp->dccps_awh))) {
		dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);

		if (dh->dccph_type != DCCP_PKT_SYNC &&
		    (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
		     DCCP_PKT_WITHOUT_ACK_SEQ))
			dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
	} else {
		LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
					    "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
					    "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
					    "sending SYNC...\n",
			       dccp_packet_name(dh->dccph_type),
			       (unsigned long long) lswl,
			       (unsigned long long)
			       DCCP_SKB_CB(skb)->dccpd_seq,
			       (unsigned long long) dp->dccps_swh,
			       (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
			        DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
			       (unsigned long long) lawl,
			       (unsigned long long)
			       DCCP_SKB_CB(skb)->dccpd_ack_seq,
			       (unsigned long long) dp->dccps_awh);
		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
		return -1;
	}

	return 0;
}

static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
				  const struct dccp_hdr *dh, const unsigned len)
{
	struct dccp_sock *dp = dccp_sk(sk);

	switch (dccp_hdr(skb)->dccph_type) {
	case DCCP_PKT_DATAACK:
	case DCCP_PKT_DATA:
		/*
		 * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
		 * option if it is.
		 */
		__skb_pull(skb, dh->dccph_doff * 4);
		__skb_queue_tail(&sk->sk_receive_queue, skb);
		skb_set_owner_r(skb, sk);
		sk->sk_data_ready(sk, 0);
		return 0;
	case DCCP_PKT_ACK:
		goto discard;
	case DCCP_PKT_RESET:
		/*
		 *  Step 9: Process Reset
		 *	If P.type == Reset,
		 *		Tear down connection
		 *		S.state := TIMEWAIT
		 *		Set TIMEWAIT timer
		 *		Drop packet and return
		*/
		dccp_fin(sk, skb);
		dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
		return 0;
	case DCCP_PKT_CLOSEREQ:
		dccp_rcv_closereq(sk, skb);
		goto discard;
	case DCCP_PKT_CLOSE:
		dccp_rcv_close(sk, skb);
		return 0;
	case DCCP_PKT_REQUEST:
		/* Step 7 
            	 *   or (S.is_server and P.type == Response)
		 *   or (S.is_client and P.type == Request)
		 *   or (S.state >= OPEN and P.type == Request
		 *	and P.seqno >= S.OSR)
		 *    or (S.state >= OPEN and P.type == Response
		 *	and P.seqno >= S.OSR)
		 *    or (S.state == RESPOND and P.type == Data),
		 *  Send Sync packet acknowledging P.seqno
		 *  Drop packet and return
		 */
		if (dp->dccps_role != DCCP_ROLE_LISTEN)
			goto send_sync;
		goto check_seq;
	case DCCP_PKT_RESPONSE:
		if (dp->dccps_role != DCCP_ROLE_CLIENT)
			goto send_sync;
check_seq:
		if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
send_sync:
			dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
				       DCCP_PKT_SYNC);
		}
		break;
	case DCCP_PKT_SYNC:
		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
			       DCCP_PKT_SYNCACK);
		/*
		 * From the draft:
		 *
		 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
		 * MAY have non-zero-length application data areas, whose
		 * contents * receivers MUST ignore.
		 */
		goto discard;
	}

	DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
discard:
	__kfree_skb(skb);
	return 0;
}

int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
			 const struct dccp_hdr *dh, const unsigned len)
{
	struct dccp_sock *dp = dccp_sk(sk);

	if (dccp_check_seqno(sk, skb))
		goto discard;

	if (dccp_parse_options(sk, skb))
		goto discard;

	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
		dccp_event_ack_recv(sk, skb);

	if (dp->dccps_options.dccpo_send_ack_vector &&
	    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
			    DCCP_SKB_CB(skb)->dccpd_seq,
			    DCCP_ACKVEC_STATE_RECEIVED))
		goto discard;

	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);

	return __dccp_rcv_established(sk, skb, dh, len);
discard:
	__kfree_skb(skb);
	return 0;
}

EXPORT_SYMBOL_GPL(dccp_rcv_established);

static int dccp_rcv_request_sent_state_process(struct sock *sk,
					       struct sk_buff *skb,
					       const struct dccp_hdr *dh,
					       const unsigned len)
{
	/* 
	 *  Step 4: Prepare sequence numbers in REQUEST
	 *     If S.state == REQUEST,
	 *	  If (P.type == Response or P.type == Reset)
	 *		and S.AWL <= P.ackno <= S.AWH,
	 *	     / * Set sequence number variables corresponding to the
	 *		other endpoint, so P will pass the tests in Step 6 * /
	 *	     Set S.GSR, S.ISR, S.SWL, S.SWH
	 *	     / * Response processing continues in Step 10; Reset
	 *		processing continues in Step 9 * /
	*/
	if (dh->dccph_type == DCCP_PKT_RESPONSE) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
		struct dccp_sock *dp = dccp_sk(sk);

		/* Stop the REQUEST timer */
		inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
		BUG_TRAP(sk->sk_send_head != NULL);
		__kfree_skb(sk->sk_send_head);
		sk->sk_send_head = NULL;

		if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
			       dp->dccps_awl, dp->dccps_awh)) {
			dccp_pr_debug("invalid ackno: S.AWL=%llu, "
				      "P.ackno=%llu, S.AWH=%llu \n",
				      (unsigned long long)dp->dccps_awl,
			   (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
				      (unsigned long long)dp->dccps_awh);
			goto out_invalid_packet;
		}

		if (dccp_parse_options(sk, skb))
			goto out_invalid_packet;

                if (dp->dccps_options.dccpo_send_ack_vector &&
                    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
                                    DCCP_SKB_CB(skb)->dccpd_seq,
                                    DCCP_ACKVEC_STATE_RECEIVED))
                        goto out_invalid_packet; /* FIXME: change error code */

		dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
		dccp_update_gsr(sk, dp->dccps_isr);
		/*
		 * SWL and AWL are initially adjusted so that they are not less than
		 * the initial Sequence Numbers received and sent, respectively:
		 *	SWL := max(GSR + 1 - floor(W/4), ISR),
		 *	AWL := max(GSS - W' + 1, ISS).
		 * These adjustments MUST be applied only at the beginning of the
		 * connection.
		 *
		 * AWL was adjusted in dccp_v4_connect -acme
		 */
		dccp_set_seqno(&dp->dccps_swl,
			       max48(dp->dccps_swl, dp->dccps_isr));

		dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);

		/*
		 *    Step 10: Process REQUEST state (second part)
		 *       If S.state == REQUEST,
		 *	  / * If we get here, P is a valid Response from the
		 *	      server (see Step 4), and we should move to
		 *	      PARTOPEN state. PARTOPEN means send an Ack,
		 *	      don't send Data packets, retransmit Acks
		 *	      periodically, and always include any Init Cookie
		 *	      from the Response * /
		 *	  S.state := PARTOPEN
		 *	  Set PARTOPEN timer
		 * 	  Continue with S.state == PARTOPEN
		 *	  / * Step 12 will send the Ack completing the
		 *	      three-way handshake * /
		 */
		dccp_set_state(sk, DCCP_PARTOPEN);

		/* Make sure socket is routed, for correct metrics. */
		icsk->icsk_af_ops->rebuild_header(sk);

		if (!sock_flag(sk, SOCK_DEAD)) {
			sk->sk_state_change(sk);
			sk_wake_async(sk, 0, POLL_OUT);
		}

		if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
		    icsk->icsk_accept_queue.rskq_defer_accept) {
			/* Save one ACK. Data will be ready after
			 * several ticks, if write_pending is set.
			 *
			 * It may be deleted, but with this feature tcpdumps
			 * look so _wonderfully_ clever, that I was not able
			 * to stand against the temptation 8)     --ANK
			 */
			/*
			 * OK, in DCCP we can as well do a similar trick, its
			 * even in the draft, but there is no need for us to
			 * schedule an ack here, as dccp_sendmsg does this for
			 * us, also stated in the draft. -acme
			 */
			__kfree_skb(skb);
			return 0;
		} 
		dccp_send_ack(sk);
		return -1;
	}

out_invalid_packet:
	/* dccp_v4_do_rcv will send a reset */
	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	return 1; 
}

static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
						   struct sk_buff *skb,
						   const struct dccp_hdr *dh,
						   const unsigned len)
{
	int queued = 0;

	switch (dh->dccph_type) {
	case DCCP_PKT_RESET:
		inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
		break;
	case DCCP_PKT_DATA:
		if (sk->sk_state == DCCP_RESPOND)
			break;
	case DCCP_PKT_DATAACK:
	case DCCP_PKT_ACK:
		/*
		 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
		 * here but only if we haven't used the DELACK timer for
		 * something else, like sending a delayed ack for a TIMESTAMP
		 * echo, etc, for now were not clearing it, sending an extra
		 * ACK when there is nothing else to do in DELACK is not a big
		 * deal after all.
		 */

		/* Stop the PARTOPEN timer */
		if (sk->sk_state == DCCP_PARTOPEN)
			inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);

		dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
		dccp_set_state(sk, DCCP_OPEN);

		if (dh->dccph_type == DCCP_PKT_DATAACK ||
		    dh->dccph_type == DCCP_PKT_DATA) {
			__dccp_rcv_established(sk, skb, dh, len);
			queued = 1; /* packet was queued
				       (by __dccp_rcv_established) */
		}
		break;
	}

	return queued;
}

int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
			   struct dccp_hdr *dh, unsigned len)
{
	struct dccp_sock *dp = dccp_sk(sk);
	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
	const int old_state = sk->sk_state;
	int queued = 0;

	/*
	 *  Step 3: Process LISTEN state
	 *  	(Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
	 *
	 *     If S.state == LISTEN,
	 *	  If P.type == Request or P contains a valid Init Cookie
	 *	  	option,
	 *	     * Must scan the packet's options to check for an Init
	 *		Cookie.  Only the Init Cookie is processed here,
	 *		however; other options are processed in Step 8.  This
	 *		scan need only be performed if the endpoint uses Init
	 *		Cookies *
	 *	     * Generate a new socket and switch to that socket *
	 *	     Set S := new socket for this port pair
	 *	     S.state = RESPOND
	 *	     Choose S.ISS (initial seqno) or set from Init Cookie
	 *	     Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
	 *	     Continue with S.state == RESPOND
	 *	     * A Response packet will be generated in Step 11 *
	 *	  Otherwise,
	 *	     Generate Reset(No Connection) unless P.type == Reset
	 *	     Drop packet and return
	 *
	 * NOTE: the check for the packet types is done in
	 *	 dccp_rcv_state_process
	 */
	if (sk->sk_state == DCCP_LISTEN) {
		if (dh->dccph_type == DCCP_PKT_REQUEST) {
			if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
								    skb) < 0)
				return 1;

			/* FIXME: do congestion control initialization */
			goto discard;
		}
		if (dh->dccph_type == DCCP_PKT_RESET)
			goto discard;

		/* Caller (dccp_v4_do_rcv) will send Reset */
		dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
		return 1;
	}

	if (sk->sk_state != DCCP_REQUESTING) {
		if (dccp_check_seqno(sk, skb))
			goto discard;

		/*
		 * Step 8: Process options and mark acknowledgeable
		 */
		if (dccp_parse_options(sk, skb))
			goto discard;

		if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
			dccp_event_ack_recv(sk, skb);

 		if (dp->dccps_options.dccpo_send_ack_vector &&
		    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
 				    DCCP_SKB_CB(skb)->dccpd_seq,
 				    DCCP_ACKVEC_STATE_RECEIVED))
 			goto discard;

		ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
		ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
	}

	/*
	 *  Step 9: Process Reset
	 *	If P.type == Reset,
	 *		Tear down connection
	 *		S.state := TIMEWAIT
	 *		Set TIMEWAIT timer
	 *		Drop packet and return
	*/
	if (dh->dccph_type == DCCP_PKT_RESET) {
		/*
		 * Queue the equivalent of TCP fin so that dccp_recvmsg
		 * exits the loop
		 */
		dccp_fin(sk, skb);
		dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
		return 0;
		/*
		 *   Step 7: Check for unexpected packet types
		 *      If (S.is_server and P.type == CloseReq)
		 *	    or (S.is_server and P.type == Response)
		 *	    or (S.is_client and P.type == Request)
		 *	    or (S.state == RESPOND and P.type == Data),
		 *	  Send Sync packet acknowledging P.seqno
		 *	  Drop packet and return
		 */
	} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
		    (dh->dccph_type == DCCP_PKT_RESPONSE ||
		     dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
		    (dp->dccps_role == DCCP_ROLE_CLIENT &&
		     dh->dccph_type == DCCP_PKT_REQUEST) ||
		    (sk->sk_state == DCCP_RESPOND &&
		     dh->dccph_type == DCCP_PKT_DATA)) {
		dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
		goto discard;
	} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
		dccp_rcv_closereq(sk, skb);
		goto discard;
	} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
		dccp_rcv_close(sk, skb);
		return 0;
	}

	if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
		dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
		goto discard;
	}

	switch (sk->sk_state) {
	case DCCP_CLOSED:
		dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
		return 1;

	case DCCP_REQUESTING:
		/* FIXME: do congestion control initialization */

		queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
		if (queued >= 0)
			return queued;

		__kfree_skb(skb);
		return 0;

	case DCCP_RESPOND:
	case DCCP_PARTOPEN:
		queued = dccp_rcv_respond_partopen_state_process(sk, skb,
								 dh, len);
		break;
	}

	if (dh->dccph_type == DCCP_PKT_ACK ||
	    dh->dccph_type == DCCP_PKT_DATAACK) {
		switch (old_state) {
		case DCCP_PARTOPEN:
			sk->sk_state_change(sk);
			sk_wake_async(sk, 0, POLL_OUT);
			break;
		}
	}

	if (!queued) { 
discard:
		__kfree_skb(skb);
	}
	return 0;
}

EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
Commit	Line	Data
7c657876 ACM	1	/*
	2	* net/dccp/input.c
	3	*
	4	* An implementation of the DCCP protocol
	5	* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version
	10	* 2 of the License, or (at your option) any later version.
	11	*/
	12
	13	#include <linux/config.h>
	14	#include <linux/dccp.h>
	15	#include <linux/skbuff.h>
	16
	17	#include <net/sock.h>
	18
ae31c339	19	#include "ackvec.h"
7c657876 ACM	20	#include "ccid.h"
	21	#include "dccp.h"
	22
	23	static void dccp_fin(struct sock sk, struct sk_buff skb)
	24	{
	25	sk->sk_shutdown \|= RCV_SHUTDOWN;
	26	sock_set_flag(sk, SOCK_DONE);
	27	__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
	28	__skb_queue_tail(&sk->sk_receive_queue, skb);
	29	skb_set_owner_r(skb, sk);
	30	sk->sk_data_ready(sk, 0);
	31	}
	32
	33	static void dccp_rcv_close(struct sock sk, struct sk_buff skb)
	34	{
017487d7	35	dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
7ad07e7c ACM	36	dccp_fin(sk, skb);
7ad07e7c ACM	37	dccp_set_state(sk, DCCP_CLOSED);
331968bd	38	sk_wake_async(sk, 1, POLL_HUP);
7c657876 ACM	39	}
	40
	41	static void dccp_rcv_closereq(struct sock sk, struct sk_buff skb)
	42	{
	43	/*
	44	* Step 7: Check for unexpected packet types
	45	* If (S.is_server and P.type == CloseReq)
	46	* Send Sync packet acknowledging P.seqno
	47	* Drop packet and return
	48	*/
	49	if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
e92ae93a	50	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
7c657876 ACM	51	return;
	52	}
	53
811265b8 ACM	54	if (sk->sk_state != DCCP_CLOSING)
811265b8 ACM	55	dccp_set_state(sk, DCCP_CLOSING);
7ad07e7c	56	dccp_send_close(sk, 0);
7c657876 ACM	57	}
7c657876 ACM	58
c25a18ba	59	static void dccp_event_ack_recv(struct sock sk, struct sk_buff skb)
7c657876 ACM	60	{
	61	struct dccp_sock *dp = dccp_sk(sk);
	62
	63	if (dp->dccps_options.dccpo_send_ack_vector)
ae31c339 ACM	64	dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
ae31c339 ACM	65	DCCP_SKB_CB(skb)->dccpd_ack_seq);
7c657876 ACM	66	}
	67
	68	static int dccp_check_seqno(struct sock sk, struct sk_buff skb)
	69	{
	70	const struct dccp_hdr *dh = dccp_hdr(skb);
	71	struct dccp_sock *dp = dccp_sk(sk);
e92ae93a	72	u64 lswl, lawl;
7c657876 ACM	73
	74	/*
	75	* Step 5: Prepare sequence numbers for Sync
	76	* If P.type == Sync or P.type == SyncAck,
	77	* If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
	78	* / * P is valid, so update sequence number variables
	79	* accordingly. After this update, P will pass the tests
	80	* in Step 6. A SyncAck is generated if necessary in
	81	* Step 15 * /
	82	* Update S.GSR, S.SWL, S.SWH
	83	* Otherwise,
	84	* Drop packet and return
	85	*/
	86	if (dh->dccph_type == DCCP_PKT_SYNC \|\|
	87	dh->dccph_type == DCCP_PKT_SYNCACK) {
7690af3f ACM	88	if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
7690af3f ACM	89	dp->dccps_awl, dp->dccps_awh) &&
7c657876 ACM	90	!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
	91	dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
	92	else
	93	return -1;
e92ae93a ACM	94	}
e92ae93a ACM	95
7c657876 ACM	96	/*
	97	* Step 6: Check sequence numbers
	98	* Let LSWL = S.SWL and LAWL = S.AWL
	99	* If P.type == CloseReq or P.type == Close or P.type == Reset,
	100	* LSWL := S.GSR + 1, LAWL := S.GAR
	101	* If LSWL <= P.seqno <= S.SWH
	102	* and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
	103	* Update S.GSR, S.SWL, S.SWH
	104	* If P.type != Sync,
	105	* Update S.GAR
	106	* Otherwise,
	107	* Send Sync packet acknowledging P.seqno
	108	* Drop packet and return
	109	*/
e92ae93a ACM	110	lswl = dp->dccps_swl;
	111	lawl = dp->dccps_awl;
	112
	113	if (dh->dccph_type == DCCP_PKT_CLOSEREQ \|\|
c59eab46 ACM	114	dh->dccph_type == DCCP_PKT_CLOSE \|\|
c59eab46 ACM	115	dh->dccph_type == DCCP_PKT_RESET) {
7c657876 ACM	116	lswl = dp->dccps_gsr;
	117	dccp_inc_seqno(&lswl);
	118	lawl = dp->dccps_gar;
	119	}
	120
	121	if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
	122	(DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ \|\|
7690af3f ACM	123	between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
7690af3f ACM	124	lawl, dp->dccps_awh))) {
7c657876 ACM	125	dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
	126
	127	if (dh->dccph_type != DCCP_PKT_SYNC &&
7690af3f ACM	128	(DCCP_SKB_CB(skb)->dccpd_ack_seq !=
7690af3f ACM	129	DCCP_PKT_WITHOUT_ACK_SEQ))
7c657876 ACM	130	dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
7c657876 ACM	131	} else {
a3054d48 ACM	132	LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
	133	"(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
	134	"(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
	135	"sending SYNC...\n",
	136	dccp_packet_name(dh->dccph_type),
58e45131 DM	137	(unsigned long long) lswl,
	138	(unsigned long long)
	139	DCCP_SKB_CB(skb)->dccpd_seq,
	140	(unsigned long long) dp->dccps_swh,
a3054d48 ACM	141	(DCCP_SKB_CB(skb)->dccpd_ack_seq ==
a3054d48 ACM	142	DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
58e45131 DM	143	(unsigned long long) lawl,
	144	(unsigned long long)
	145	DCCP_SKB_CB(skb)->dccpd_ack_seq,
	146	(unsigned long long) dp->dccps_awh);
e92ae93a	147	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
7c657876 ACM	148	return -1;
	149	}
	150
	151	return 0;
	152	}
	153
c25a18ba ACM	154	static int __dccp_rcv_established(struct sock sk, struct sk_buff skb,
c25a18ba ACM	155	const struct dccp_hdr *dh, const unsigned len)
7c657876 ACM	156	{
	157	struct dccp_sock *dp = dccp_sk(sk);
	158
7c657876 ACM	159	switch (dccp_hdr(skb)->dccph_type) {
	160	case DCCP_PKT_DATAACK:
	161	case DCCP_PKT_DATA:
	162	/*
7690af3f ACM	163	* FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
7690af3f ACM	164	* option if it is.
7c657876 ACM	165	*/
	166	__skb_pull(skb, dh->dccph_doff * 4);
	167	__skb_queue_tail(&sk->sk_receive_queue, skb);
	168	skb_set_owner_r(skb, sk);
	169	sk->sk_data_ready(sk, 0);
	170	return 0;
	171	case DCCP_PKT_ACK:
	172	goto discard;
	173	case DCCP_PKT_RESET:
	174	/*
	175	* Step 9: Process Reset
	176	* If P.type == Reset,
	177	* Tear down connection
	178	* S.state := TIMEWAIT
	179	* Set TIMEWAIT timer
	180	* Drop packet and return
	181	*/
	182	dccp_fin(sk, skb);
	183	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
	184	return 0;
	185	case DCCP_PKT_CLOSEREQ:
	186	dccp_rcv_closereq(sk, skb);
	187	goto discard;
	188	case DCCP_PKT_CLOSE:
	189	dccp_rcv_close(sk, skb);
	190	return 0;
	191	case DCCP_PKT_REQUEST:
	192	/* Step 7
	193	* or (S.is_server and P.type == Response)
	194	* or (S.is_client and P.type == Request)
	195	* or (S.state >= OPEN and P.type == Request
	196	* and P.seqno >= S.OSR)
	197	* or (S.state >= OPEN and P.type == Response
	198	* and P.seqno >= S.OSR)
	199	* or (S.state == RESPOND and P.type == Data),
	200	* Send Sync packet acknowledging P.seqno
	201	* Drop packet and return
	202	*/
	203	if (dp->dccps_role != DCCP_ROLE_LISTEN)
	204	goto send_sync;
	205	goto check_seq;
	206	case DCCP_PKT_RESPONSE:
	207	if (dp->dccps_role != DCCP_ROLE_CLIENT)
	208	goto send_sync;
	209	check_seq:
	210	if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
	211	send_sync:
e92ae93a ACM	212	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
e92ae93a ACM	213	DCCP_PKT_SYNC);
7c657876 ACM	214	}
7c657876 ACM	215	break;
e92ae93a ACM	216	case DCCP_PKT_SYNC:
	217	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
	218	DCCP_PKT_SYNCACK);
	219	/*
	220	* From the draft:
	221	*
	222	* As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
	223	* MAY have non-zero-length application data areas, whose
	224	* contents * receivers MUST ignore.
	225	*/
	226	goto discard;
7c657876 ACM	227	}
	228
	229	DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
	230	discard:
	231	__kfree_skb(skb);
	232	return 0;
	233	}
	234
709dd3aa AB	235	int dccp_rcv_established(struct sock sk, struct sk_buff skb,
	236	const struct dccp_hdr *dh, const unsigned len)
	237	{
	238	struct dccp_sock *dp = dccp_sk(sk);
	239
	240	if (dccp_check_seqno(sk, skb))
	241	goto discard;
	242
	243	if (dccp_parse_options(sk, skb))
	244	goto discard;
	245
	246	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
	247	dccp_event_ack_recv(sk, skb);
	248
	249	if (dp->dccps_options.dccpo_send_ack_vector &&
	250	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	251	DCCP_SKB_CB(skb)->dccpd_seq,
	252	DCCP_ACKVEC_STATE_RECEIVED))
	253	goto discard;
	254
	255	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	256	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
	257
	258	return __dccp_rcv_established(sk, skb, dh, len);
	259	discard:
	260	__kfree_skb(skb);
	261	return 0;
	262	}
	263
f21e68ca ACM	264	EXPORT_SYMBOL_GPL(dccp_rcv_established);
f21e68ca ACM	265
7c657876 ACM	266	static int dccp_rcv_request_sent_state_process(struct sock *sk,
	267	struct sk_buff *skb,
	268	const struct dccp_hdr *dh,
	269	const unsigned len)
	270	{
	271	/*
	272	* Step 4: Prepare sequence numbers in REQUEST
	273	* If S.state == REQUEST,
	274	* If (P.type == Response or P.type == Reset)
	275	* and S.AWL <= P.ackno <= S.AWH,
	276	* / * Set sequence number variables corresponding to the
	277	* other endpoint, so P will pass the tests in Step 6 * /
	278	* Set S.GSR, S.ISR, S.SWL, S.SWH
	279	* / * Response processing continues in Step 10; Reset
	280	* processing continues in Step 9 * /
	281	*/
	282	if (dh->dccph_type == DCCP_PKT_RESPONSE) {
	283	const struct inet_connection_sock *icsk = inet_csk(sk);
	284	struct dccp_sock *dp = dccp_sk(sk);
	285
	286	/* Stop the REQUEST timer */
	287	inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
	288	BUG_TRAP(sk->sk_send_head != NULL);
	289	__kfree_skb(sk->sk_send_head);
	290	sk->sk_send_head = NULL;
	291
7690af3f ACM	292	if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
	293	dp->dccps_awl, dp->dccps_awh)) {
	294	dccp_pr_debug("invalid ackno: S.AWL=%llu, "
	295	"P.ackno=%llu, S.AWH=%llu \n",
	296	(unsigned long long)dp->dccps_awl,
	297	(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
	298	(unsigned long long)dp->dccps_awh);
7c657876 ACM	299	goto out_invalid_packet;
7c657876 ACM	300	}
9e377202	301
afe00251 AB	302	if (dccp_parse_options(sk, skb))
	303	goto out_invalid_packet;
	304
9e377202 AB	305	if (dp->dccps_options.dccpo_send_ack_vector &&
	306	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	307	DCCP_SKB_CB(skb)->dccpd_seq,
	308	DCCP_ACKVEC_STATE_RECEIVED))
	309	goto out_invalid_packet; /* FIXME: change error code */
7c657876 ACM	310
7c657876 ACM	311	dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
03ace394 ACM	312	dccp_update_gsr(sk, dp->dccps_isr);
	313	/*
	314	* SWL and AWL are initially adjusted so that they are not less than
	315	* the initial Sequence Numbers received and sent, respectively:
	316	* SWL := max(GSR + 1 - floor(W/4), ISR),
	317	* AWL := max(GSS - W' + 1, ISS).
	318	* These adjustments MUST be applied only at the beginning of the
	319	* connection.
	320	*
	321	* AWL was adjusted in dccp_v4_connect -acme
	322	*/
	323	dccp_set_seqno(&dp->dccps_swl,
	324	max48(dp->dccps_swl, dp->dccps_isr));
7c657876	325
d83d8461	326	dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
7c657876 ACM	327
	328	/*
	329	* Step 10: Process REQUEST state (second part)
	330	* If S.state == REQUEST,
7690af3f ACM	331	* / * If we get here, P is a valid Response from the
	332	* server (see Step 4), and we should move to
	333	* PARTOPEN state. PARTOPEN means send an Ack,
	334	* don't send Data packets, retransmit Acks
	335	* periodically, and always include any Init Cookie
	336	* from the Response * /
7c657876 ACM	337	* S.state := PARTOPEN
	338	* Set PARTOPEN timer
	339	* Continue with S.state == PARTOPEN
7690af3f ACM	340	* / * Step 12 will send the Ack completing the
7690af3f ACM	341	* three-way handshake * /
7c657876 ACM	342	*/
	343	dccp_set_state(sk, DCCP_PARTOPEN);
	344
	345	/* Make sure socket is routed, for correct metrics. */
57cca05a	346	icsk->icsk_af_ops->rebuild_header(sk);
7c657876 ACM	347
	348	if (!sock_flag(sk, SOCK_DEAD)) {
	349	sk->sk_state_change(sk);
	350	sk_wake_async(sk, 0, POLL_OUT);
	351	}
	352
	353	if (sk->sk_write_pending \|\| icsk->icsk_ack.pingpong \|\|
	354	icsk->icsk_accept_queue.rskq_defer_accept) {
	355	/* Save one ACK. Data will be ready after
	356	* several ticks, if write_pending is set.
	357	*
	358	* It may be deleted, but with this feature tcpdumps
	359	* look so _wonderfully_ clever, that I was not able
	360	* to stand against the temptation 8) --ANK
	361	*/
	362	/*
	363	* OK, in DCCP we can as well do a similar trick, its
	364	* even in the draft, but there is no need for us to
	365	* schedule an ack here, as dccp_sendmsg does this for
	366	* us, also stated in the draft. -acme
	367	*/
	368	__kfree_skb(skb);
	369	return 0;
	370	}
	371	dccp_send_ack(sk);
	372	return -1;
	373	}
	374
	375	out_invalid_packet:
0c10c5d9 ACM	376	/* dccp_v4_do_rcv will send a reset */
	377	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	378	return 1;
7c657876 ACM	379	}
	380
	381	static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
	382	struct sk_buff *skb,
	383	const struct dccp_hdr *dh,
	384	const unsigned len)
	385	{
	386	int queued = 0;
	387
	388	switch (dh->dccph_type) {
	389	case DCCP_PKT_RESET:
	390	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
	391	break;
2a9bc9bb ACM	392	case DCCP_PKT_DATA:
	393	if (sk->sk_state == DCCP_RESPOND)
	394	break;
7c657876 ACM	395	case DCCP_PKT_DATAACK:
	396	case DCCP_PKT_ACK:
	397	/*
7690af3f ACM	398	* FIXME: we should be reseting the PARTOPEN (DELACK) timer
	399	* here but only if we haven't used the DELACK timer for
	400	* something else, like sending a delayed ack for a TIMESTAMP
	401	* echo, etc, for now were not clearing it, sending an extra
	402	* ACK when there is nothing else to do in DELACK is not a big
	403	* deal after all.
7c657876 ACM	404	*/
	405
	406	/* Stop the PARTOPEN timer */
	407	if (sk->sk_state == DCCP_PARTOPEN)
	408	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
	409
	410	dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
	411	dccp_set_state(sk, DCCP_OPEN);
	412
2a9bc9bb ACM	413	if (dh->dccph_type == DCCP_PKT_DATAACK \|\|
2a9bc9bb ACM	414	dh->dccph_type == DCCP_PKT_DATA) {
709dd3aa	415	__dccp_rcv_established(sk, skb, dh, len);
7690af3f	416	queued = 1; /* packet was queued
709dd3aa	417	(by __dccp_rcv_established) */
7c657876 ACM	418	}
	419	break;
	420	}
	421
	422	return queued;
	423	}
	424
	425	int dccp_rcv_state_process(struct sock sk, struct sk_buff skb,
	426	struct dccp_hdr *dh, unsigned len)
	427	{
	428	struct dccp_sock *dp = dccp_sk(sk);
0c10c5d9	429	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
7c657876 ACM	430	const int old_state = sk->sk_state;
	431	int queued = 0;
	432
8649b0d4 ACM	433	/*
	434	* Step 3: Process LISTEN state
	435	* (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
	436	*
	437	* If S.state == LISTEN,
	438	* If P.type == Request or P contains a valid Init Cookie
	439	* option,
	440	* * Must scan the packet's options to check for an Init
	441	* Cookie. Only the Init Cookie is processed here,
	442	* however; other options are processed in Step 8. This
	443	* scan need only be performed if the endpoint uses Init
	444	* Cookies *
	445	* * Generate a new socket and switch to that socket *
	446	* Set S := new socket for this port pair
	447	* S.state = RESPOND
	448	* Choose S.ISS (initial seqno) or set from Init Cookie
	449	* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
	450	* Continue with S.state == RESPOND
	451	* * A Response packet will be generated in Step 11 *
	452	* Otherwise,
	453	* Generate Reset(No Connection) unless P.type == Reset
	454	* Drop packet and return
	455	*
	456	* NOTE: the check for the packet types is done in
	457	* dccp_rcv_state_process
	458	*/
	459	if (sk->sk_state == DCCP_LISTEN) {
	460	if (dh->dccph_type == DCCP_PKT_REQUEST) {
57cca05a ACM	461	if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
57cca05a ACM	462	skb) < 0)
8649b0d4 ACM	463	return 1;
	464
	465	/* FIXME: do congestion control initialization */
	466	goto discard;
	467	}
	468	if (dh->dccph_type == DCCP_PKT_RESET)
	469	goto discard;
	470
0c10c5d9 ACM	471	/* Caller (dccp_v4_do_rcv) will send Reset */
0c10c5d9 ACM	472	dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
8649b0d4 ACM	473	return 1;
	474	}
	475
	476	if (sk->sk_state != DCCP_REQUESTING) {
7c657876 ACM	477	if (dccp_check_seqno(sk, skb))
	478	goto discard;
	479
	480	/*
	481	* Step 8: Process options and mark acknowledgeable
	482	*/
	483	if (dccp_parse_options(sk, skb))
	484	goto discard;
	485
0c10c5d9	486	if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
7c657876 ACM	487	dccp_event_ack_recv(sk, skb);
7c657876 ACM	488
ae31c339 ACM	489	if (dp->dccps_options.dccpo_send_ack_vector &&
	490	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	491	DCCP_SKB_CB(skb)->dccpd_seq,
	492	DCCP_ACKVEC_STATE_RECEIVED))
	493	goto discard;
e84a9f5e AB	494
	495	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	496	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
7c657876 ACM	497	}
	498
	499	/*
	500	* Step 9: Process Reset
	501	* If P.type == Reset,
	502	* Tear down connection
	503	* S.state := TIMEWAIT
	504	* Set TIMEWAIT timer
	505	* Drop packet and return
	506	*/
	507	if (dh->dccph_type == DCCP_PKT_RESET) {
7690af3f ACM	508	/*
	509	* Queue the equivalent of TCP fin so that dccp_recvmsg
	510	* exits the loop
	511	*/
7c657876 ACM	512	dccp_fin(sk, skb);
	513	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
	514	return 0;
	515	/*
	516	* Step 7: Check for unexpected packet types
	517	* If (S.is_server and P.type == CloseReq)
	518	* or (S.is_server and P.type == Response)
	519	* or (S.is_client and P.type == Request)
	520	* or (S.state == RESPOND and P.type == Data),
	521	* Send Sync packet acknowledging P.seqno
	522	* Drop packet and return
	523	*/
	524	} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
7690af3f ACM	525	(dh->dccph_type == DCCP_PKT_RESPONSE \|\|
7690af3f ACM	526	dh->dccph_type == DCCP_PKT_CLOSEREQ)) \|\|
7c657876 ACM	527	(dp->dccps_role == DCCP_ROLE_CLIENT &&
7c657876 ACM	528	dh->dccph_type == DCCP_PKT_REQUEST) \|\|
7690af3f ACM	529	(sk->sk_state == DCCP_RESPOND &&
7690af3f ACM	530	dh->dccph_type == DCCP_PKT_DATA)) {
0c10c5d9	531	dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
7c657876	532	goto discard;
7ad07e7c ACM	533	} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
	534	dccp_rcv_closereq(sk, skb);
	535	goto discard;
	536	} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
	537	dccp_rcv_close(sk, skb);
	538	return 0;
7c657876 ACM	539	}
7c657876 ACM	540
2b80230a	541	if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
0c10c5d9	542	dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
2b80230a ACM	543	goto discard;
	544	}
	545
7c657876 ACM	546	switch (sk->sk_state) {
7c657876 ACM	547	case DCCP_CLOSED:
0c10c5d9	548	dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
7c657876 ACM	549	return 1;
7c657876 ACM	550
7c657876 ACM	551	case DCCP_REQUESTING:
	552	/* FIXME: do congestion control initialization */
	553
	554	queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
	555	if (queued >= 0)
	556	return queued;
	557
	558	__kfree_skb(skb);
	559	return 0;
	560
	561	case DCCP_RESPOND:
	562	case DCCP_PARTOPEN:
7690af3f ACM	563	queued = dccp_rcv_respond_partopen_state_process(sk, skb,
7690af3f ACM	564	dh, len);
7c657876 ACM	565	break;
	566	}
	567
7690af3f ACM	568	if (dh->dccph_type == DCCP_PKT_ACK \|\|
7690af3f ACM	569	dh->dccph_type == DCCP_PKT_DATAACK) {
7c657876 ACM	570	switch (old_state) {
	571	case DCCP_PARTOPEN:
	572	sk->sk_state_change(sk);
	573	sk_wake_async(sk, 0, POLL_OUT);
	574	break;
	575	}
	576	}
	577
	578	if (!queued) {
	579	discard:
	580	__kfree_skb(skb);
	581	}
	582	return 0;
	583	}
f21e68ca ACM	584
f21e68ca ACM	585	EXPORT_SYMBOL_GPL(dccp_rcv_state_process);