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

/*
 *  net/dccp/input.c
 * 
 *  An implementation of the DCCP protocol
 *  Arnaldo Carvalho de Melo <[email protected]>
 *
 *	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/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 (dccp_msk(sk)->dccpms_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 RFC 4340, sec. 5.7
		 *
		 * 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 (dccp_msk(sk)->dccpms_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 (dccp_msk(sk)->dccpms_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 (dccp_msk(sk)->dccpms_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 <[email protected]>
	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
7c657876 ACM	13	#include <linux/dccp.h>
	14	#include <linux/skbuff.h>
	15
	16	#include <net/sock.h>
	17
ae31c339	18	#include "ackvec.h"
7c657876 ACM	19	#include "ccid.h"
	20	#include "dccp.h"
	21
	22	static void dccp_fin(struct sock sk, struct sk_buff skb)
	23	{
	24	sk->sk_shutdown \|= RCV_SHUTDOWN;
	25	sock_set_flag(sk, SOCK_DONE);
	26	__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
	27	__skb_queue_tail(&sk->sk_receive_queue, skb);
	28	skb_set_owner_r(skb, sk);
	29	sk->sk_data_ready(sk, 0);
	30	}
	31
	32	static void dccp_rcv_close(struct sock sk, struct sk_buff skb)
	33	{
017487d7	34	dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
7ad07e7c ACM	35	dccp_fin(sk, skb);
7ad07e7c ACM	36	dccp_set_state(sk, DCCP_CLOSED);
331968bd	37	sk_wake_async(sk, 1, POLL_HUP);
7c657876 ACM	38	}
	39
	40	static void dccp_rcv_closereq(struct sock sk, struct sk_buff skb)
	41	{
	42	/*
	43	* Step 7: Check for unexpected packet types
	44	* If (S.is_server and P.type == CloseReq)
	45	* Send Sync packet acknowledging P.seqno
	46	* Drop packet and return
	47	*/
	48	if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
e92ae93a	49	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
7c657876 ACM	50	return;
	51	}
	52
811265b8 ACM	53	if (sk->sk_state != DCCP_CLOSING)
811265b8 ACM	54	dccp_set_state(sk, DCCP_CLOSING);
7ad07e7c	55	dccp_send_close(sk, 0);
7c657876 ACM	56	}
7c657876 ACM	57
c25a18ba	58	static void dccp_event_ack_recv(struct sock sk, struct sk_buff skb)
7c657876 ACM	59	{
	60	struct dccp_sock *dp = dccp_sk(sk);
	61
a4bf3902	62	if (dccp_msk(sk)->dccpms_send_ack_vector)
ae31c339 ACM	63	dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
ae31c339 ACM	64	DCCP_SKB_CB(skb)->dccpd_ack_seq);
7c657876 ACM	65	}
	66
	67	static int dccp_check_seqno(struct sock sk, struct sk_buff skb)
	68	{
	69	const struct dccp_hdr *dh = dccp_hdr(skb);
	70	struct dccp_sock *dp = dccp_sk(sk);
e92ae93a	71	u64 lswl, lawl;
7c657876 ACM	72
	73	/*
	74	* Step 5: Prepare sequence numbers for Sync
	75	* If P.type == Sync or P.type == SyncAck,
	76	* If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
	77	* / * P is valid, so update sequence number variables
	78	* accordingly. After this update, P will pass the tests
	79	* in Step 6. A SyncAck is generated if necessary in
	80	* Step 15 * /
	81	* Update S.GSR, S.SWL, S.SWH
	82	* Otherwise,
	83	* Drop packet and return
	84	*/
	85	if (dh->dccph_type == DCCP_PKT_SYNC \|\|
	86	dh->dccph_type == DCCP_PKT_SYNCACK) {
7690af3f ACM	87	if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
7690af3f ACM	88	dp->dccps_awl, dp->dccps_awh) &&
7c657876 ACM	89	!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
	90	dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
	91	else
	92	return -1;
e92ae93a ACM	93	}
e92ae93a ACM	94
7c657876 ACM	95	/*
	96	* Step 6: Check sequence numbers
	97	* Let LSWL = S.SWL and LAWL = S.AWL
	98	* If P.type == CloseReq or P.type == Close or P.type == Reset,
	99	* LSWL := S.GSR + 1, LAWL := S.GAR
	100	* If LSWL <= P.seqno <= S.SWH
	101	* and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
	102	* Update S.GSR, S.SWL, S.SWH
	103	* If P.type != Sync,
	104	* Update S.GAR
	105	* Otherwise,
	106	* Send Sync packet acknowledging P.seqno
	107	* Drop packet and return
	108	*/
e92ae93a ACM	109	lswl = dp->dccps_swl;
	110	lawl = dp->dccps_awl;
	111
	112	if (dh->dccph_type == DCCP_PKT_CLOSEREQ \|\|
c59eab46 ACM	113	dh->dccph_type == DCCP_PKT_CLOSE \|\|
c59eab46 ACM	114	dh->dccph_type == DCCP_PKT_RESET) {
7c657876 ACM	115	lswl = dp->dccps_gsr;
	116	dccp_inc_seqno(&lswl);
	117	lawl = dp->dccps_gar;
	118	}
	119
	120	if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
	121	(DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ \|\|
7690af3f ACM	122	between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
7690af3f ACM	123	lawl, dp->dccps_awh))) {
7c657876 ACM	124	dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
	125
	126	if (dh->dccph_type != DCCP_PKT_SYNC &&
7690af3f ACM	127	(DCCP_SKB_CB(skb)->dccpd_ack_seq !=
7690af3f ACM	128	DCCP_PKT_WITHOUT_ACK_SEQ))
7c657876 ACM	129	dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
7c657876 ACM	130	} else {
a3054d48 ACM	131	LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
	132	"(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
	133	"(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
	134	"sending SYNC...\n",
	135	dccp_packet_name(dh->dccph_type),
58e45131 DM	136	(unsigned long long) lswl,
	137	(unsigned long long)
	138	DCCP_SKB_CB(skb)->dccpd_seq,
	139	(unsigned long long) dp->dccps_swh,
a3054d48 ACM	140	(DCCP_SKB_CB(skb)->dccpd_ack_seq ==
a3054d48 ACM	141	DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
58e45131 DM	142	(unsigned long long) lawl,
	143	(unsigned long long)
	144	DCCP_SKB_CB(skb)->dccpd_ack_seq,
	145	(unsigned long long) dp->dccps_awh);
e92ae93a	146	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
7c657876 ACM	147	return -1;
	148	}
	149
	150	return 0;
	151	}
	152
c25a18ba ACM	153	static int __dccp_rcv_established(struct sock sk, struct sk_buff skb,
c25a18ba ACM	154	const struct dccp_hdr *dh, const unsigned len)
7c657876 ACM	155	{
	156	struct dccp_sock *dp = dccp_sk(sk);
	157
7c657876 ACM	158	switch (dccp_hdr(skb)->dccph_type) {
	159	case DCCP_PKT_DATAACK:
	160	case DCCP_PKT_DATA:
	161	/*
7690af3f ACM	162	* FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
7690af3f ACM	163	* option if it is.
7c657876 ACM	164	*/
	165	__skb_pull(skb, dh->dccph_doff * 4);
	166	__skb_queue_tail(&sk->sk_receive_queue, skb);
	167	skb_set_owner_r(skb, sk);
	168	sk->sk_data_ready(sk, 0);
	169	return 0;
	170	case DCCP_PKT_ACK:
	171	goto discard;
	172	case DCCP_PKT_RESET:
	173	/*
	174	* Step 9: Process Reset
	175	* If P.type == Reset,
	176	* Tear down connection
	177	* S.state := TIMEWAIT
	178	* Set TIMEWAIT timer
	179	* Drop packet and return
	180	*/
	181	dccp_fin(sk, skb);
	182	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
	183	return 0;
	184	case DCCP_PKT_CLOSEREQ:
	185	dccp_rcv_closereq(sk, skb);
	186	goto discard;
	187	case DCCP_PKT_CLOSE:
	188	dccp_rcv_close(sk, skb);
	189	return 0;
	190	case DCCP_PKT_REQUEST:
	191	/* Step 7
	192	* or (S.is_server and P.type == Response)
	193	* or (S.is_client and P.type == Request)
	194	* or (S.state >= OPEN and P.type == Request
	195	* and P.seqno >= S.OSR)
	196	* or (S.state >= OPEN and P.type == Response
	197	* and P.seqno >= S.OSR)
	198	* or (S.state == RESPOND and P.type == Data),
	199	* Send Sync packet acknowledging P.seqno
	200	* Drop packet and return
	201	*/
	202	if (dp->dccps_role != DCCP_ROLE_LISTEN)
	203	goto send_sync;
	204	goto check_seq;
	205	case DCCP_PKT_RESPONSE:
	206	if (dp->dccps_role != DCCP_ROLE_CLIENT)
	207	goto send_sync;
	208	check_seq:
	209	if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
	210	send_sync:
e92ae93a ACM	211	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
e92ae93a ACM	212	DCCP_PKT_SYNC);
7c657876 ACM	213	}
7c657876 ACM	214	break;
e92ae93a ACM	215	case DCCP_PKT_SYNC:
	216	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
	217	DCCP_PKT_SYNCACK);
	218	/*
0e64e94e	219	* From RFC 4340, sec. 5.7
e92ae93a ACM	220	*
	221	* As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
	222	* MAY have non-zero-length application data areas, whose
0e64e94e	223	* contents receivers MUST ignore.
e92ae93a ACM	224	*/
e92ae93a ACM	225	goto discard;
7c657876 ACM	226	}
	227
	228	DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
	229	discard:
	230	__kfree_skb(skb);
	231	return 0;
	232	}
	233
709dd3aa AB	234	int dccp_rcv_established(struct sock sk, struct sk_buff skb,
	235	const struct dccp_hdr *dh, const unsigned len)
	236	{
	237	struct dccp_sock *dp = dccp_sk(sk);
	238
	239	if (dccp_check_seqno(sk, skb))
	240	goto discard;
	241
	242	if (dccp_parse_options(sk, skb))
	243	goto discard;
	244
	245	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
	246	dccp_event_ack_recv(sk, skb);
	247
a4bf3902	248	if (dccp_msk(sk)->dccpms_send_ack_vector &&
709dd3aa AB	249	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	250	DCCP_SKB_CB(skb)->dccpd_seq,
	251	DCCP_ACKVEC_STATE_RECEIVED))
	252	goto discard;
	253
	254	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	255	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
	256
	257	return __dccp_rcv_established(sk, skb, dh, len);
	258	discard:
	259	__kfree_skb(skb);
	260	return 0;
	261	}
	262
f21e68ca ACM	263	EXPORT_SYMBOL_GPL(dccp_rcv_established);
f21e68ca ACM	264
7c657876 ACM	265	static int dccp_rcv_request_sent_state_process(struct sock *sk,
	266	struct sk_buff *skb,
	267	const struct dccp_hdr *dh,
	268	const unsigned len)
	269	{
	270	/*
	271	* Step 4: Prepare sequence numbers in REQUEST
	272	* If S.state == REQUEST,
	273	* If (P.type == Response or P.type == Reset)
	274	* and S.AWL <= P.ackno <= S.AWH,
	275	* / * Set sequence number variables corresponding to the
	276	* other endpoint, so P will pass the tests in Step 6 * /
	277	* Set S.GSR, S.ISR, S.SWL, S.SWH
	278	* / * Response processing continues in Step 10; Reset
	279	* processing continues in Step 9 * /
	280	*/
	281	if (dh->dccph_type == DCCP_PKT_RESPONSE) {
	282	const struct inet_connection_sock *icsk = inet_csk(sk);
	283	struct dccp_sock *dp = dccp_sk(sk);
	284
	285	/* Stop the REQUEST timer */
	286	inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
	287	BUG_TRAP(sk->sk_send_head != NULL);
	288	__kfree_skb(sk->sk_send_head);
	289	sk->sk_send_head = NULL;
	290
7690af3f ACM	291	if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
	292	dp->dccps_awl, dp->dccps_awh)) {
	293	dccp_pr_debug("invalid ackno: S.AWL=%llu, "
	294	"P.ackno=%llu, S.AWH=%llu \n",
	295	(unsigned long long)dp->dccps_awl,
	296	(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
	297	(unsigned long long)dp->dccps_awh);
7c657876 ACM	298	goto out_invalid_packet;
7c657876 ACM	299	}
9e377202	300
afe00251 AB	301	if (dccp_parse_options(sk, skb))
	302	goto out_invalid_packet;
	303
a4bf3902	304	if (dccp_msk(sk)->dccpms_send_ack_vector &&
9e377202 AB	305	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	306	DCCP_SKB_CB(skb)->dccpd_seq,
	307	DCCP_ACKVEC_STATE_RECEIVED))
	308	goto out_invalid_packet; /* FIXME: change error code */
7c657876 ACM	309
7c657876 ACM	310	dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
03ace394 ACM	311	dccp_update_gsr(sk, dp->dccps_isr);
	312	/*
	313	* SWL and AWL are initially adjusted so that they are not less than
	314	* the initial Sequence Numbers received and sent, respectively:
	315	* SWL := max(GSR + 1 - floor(W/4), ISR),
	316	* AWL := max(GSS - W' + 1, ISS).
	317	* These adjustments MUST be applied only at the beginning of the
	318	* connection.
	319	*
	320	* AWL was adjusted in dccp_v4_connect -acme
	321	*/
	322	dccp_set_seqno(&dp->dccps_swl,
	323	max48(dp->dccps_swl, dp->dccps_isr));
7c657876	324
d83d8461	325	dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
7c657876 ACM	326
	327	/*
	328	* Step 10: Process REQUEST state (second part)
	329	* If S.state == REQUEST,
7690af3f ACM	330	* / * If we get here, P is a valid Response from the
	331	* server (see Step 4), and we should move to
	332	* PARTOPEN state. PARTOPEN means send an Ack,
	333	* don't send Data packets, retransmit Acks
	334	* periodically, and always include any Init Cookie
	335	* from the Response * /
7c657876 ACM	336	* S.state := PARTOPEN
	337	* Set PARTOPEN timer
	338	* Continue with S.state == PARTOPEN
7690af3f ACM	339	* / * Step 12 will send the Ack completing the
7690af3f ACM	340	* three-way handshake * /
7c657876 ACM	341	*/
	342	dccp_set_state(sk, DCCP_PARTOPEN);
	343
	344	/* Make sure socket is routed, for correct metrics. */
57cca05a	345	icsk->icsk_af_ops->rebuild_header(sk);
7c657876 ACM	346
	347	if (!sock_flag(sk, SOCK_DEAD)) {
	348	sk->sk_state_change(sk);
	349	sk_wake_async(sk, 0, POLL_OUT);
	350	}
	351
	352	if (sk->sk_write_pending \|\| icsk->icsk_ack.pingpong \|\|
	353	icsk->icsk_accept_queue.rskq_defer_accept) {
	354	/* Save one ACK. Data will be ready after
	355	* several ticks, if write_pending is set.
	356	*
	357	* It may be deleted, but with this feature tcpdumps
	358	* look so _wonderfully_ clever, that I was not able
	359	* to stand against the temptation 8) --ANK
	360	*/
	361	/*
	362	* OK, in DCCP we can as well do a similar trick, its
	363	* even in the draft, but there is no need for us to
	364	* schedule an ack here, as dccp_sendmsg does this for
	365	* us, also stated in the draft. -acme
	366	*/
	367	__kfree_skb(skb);
	368	return 0;
	369	}
	370	dccp_send_ack(sk);
	371	return -1;
	372	}
	373
	374	out_invalid_packet:
0c10c5d9 ACM	375	/* dccp_v4_do_rcv will send a reset */
	376	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	377	return 1;
7c657876 ACM	378	}
	379
	380	static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
	381	struct sk_buff *skb,
	382	const struct dccp_hdr *dh,
	383	const unsigned len)
	384	{
	385	int queued = 0;
	386
	387	switch (dh->dccph_type) {
	388	case DCCP_PKT_RESET:
	389	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
	390	break;
2a9bc9bb ACM	391	case DCCP_PKT_DATA:
	392	if (sk->sk_state == DCCP_RESPOND)
	393	break;
7c657876 ACM	394	case DCCP_PKT_DATAACK:
	395	case DCCP_PKT_ACK:
	396	/*
7690af3f ACM	397	* FIXME: we should be reseting the PARTOPEN (DELACK) timer
	398	* here but only if we haven't used the DELACK timer for
	399	* something else, like sending a delayed ack for a TIMESTAMP
	400	* echo, etc, for now were not clearing it, sending an extra
	401	* ACK when there is nothing else to do in DELACK is not a big
	402	* deal after all.
7c657876 ACM	403	*/
	404
	405	/* Stop the PARTOPEN timer */
	406	if (sk->sk_state == DCCP_PARTOPEN)
	407	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
	408
	409	dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
	410	dccp_set_state(sk, DCCP_OPEN);
	411
2a9bc9bb ACM	412	if (dh->dccph_type == DCCP_PKT_DATAACK \|\|
2a9bc9bb ACM	413	dh->dccph_type == DCCP_PKT_DATA) {
709dd3aa	414	__dccp_rcv_established(sk, skb, dh, len);
7690af3f	415	queued = 1; /* packet was queued
709dd3aa	416	(by __dccp_rcv_established) */
7c657876 ACM	417	}
	418	break;
	419	}
	420
	421	return queued;
	422	}
	423
	424	int dccp_rcv_state_process(struct sock sk, struct sk_buff skb,
	425	struct dccp_hdr *dh, unsigned len)
	426	{
	427	struct dccp_sock *dp = dccp_sk(sk);
0c10c5d9	428	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
7c657876 ACM	429	const int old_state = sk->sk_state;
	430	int queued = 0;
	431
8649b0d4 ACM	432	/*
	433	* Step 3: Process LISTEN state
	434	* (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
	435	*
	436	* If S.state == LISTEN,
	437	* If P.type == Request or P contains a valid Init Cookie
	438	* option,
	439	* * Must scan the packet's options to check for an Init
	440	* Cookie. Only the Init Cookie is processed here,
	441	* however; other options are processed in Step 8. This
	442	* scan need only be performed if the endpoint uses Init
	443	* Cookies *
	444	* * Generate a new socket and switch to that socket *
	445	* Set S := new socket for this port pair
	446	* S.state = RESPOND
	447	* Choose S.ISS (initial seqno) or set from Init Cookie
	448	* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
	449	* Continue with S.state == RESPOND
	450	* * A Response packet will be generated in Step 11 *
	451	* Otherwise,
	452	* Generate Reset(No Connection) unless P.type == Reset
	453	* Drop packet and return
	454	*
	455	* NOTE: the check for the packet types is done in
	456	* dccp_rcv_state_process
	457	*/
	458	if (sk->sk_state == DCCP_LISTEN) {
	459	if (dh->dccph_type == DCCP_PKT_REQUEST) {
57cca05a ACM	460	if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
57cca05a ACM	461	skb) < 0)
8649b0d4 ACM	462	return 1;
	463
	464	/* FIXME: do congestion control initialization */
	465	goto discard;
	466	}
	467	if (dh->dccph_type == DCCP_PKT_RESET)
	468	goto discard;
	469
0c10c5d9 ACM	470	/* Caller (dccp_v4_do_rcv) will send Reset */
0c10c5d9 ACM	471	dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
8649b0d4 ACM	472	return 1;
	473	}
	474
	475	if (sk->sk_state != DCCP_REQUESTING) {
7c657876 ACM	476	if (dccp_check_seqno(sk, skb))
	477	goto discard;
	478
	479	/*
	480	* Step 8: Process options and mark acknowledgeable
	481	*/
	482	if (dccp_parse_options(sk, skb))
	483	goto discard;
	484
0c10c5d9	485	if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
7c657876 ACM	486	dccp_event_ack_recv(sk, skb);
7c657876 ACM	487
a4bf3902	488	if (dccp_msk(sk)->dccpms_send_ack_vector &&
ae31c339 ACM	489	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	490	DCCP_SKB_CB(skb)->dccpd_seq,
	491	DCCP_ACKVEC_STATE_RECEIVED))
	492	goto discard;
e84a9f5e AB	493
	494	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	495	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
7c657876 ACM	496	}
	497
	498	/*
	499	* Step 9: Process Reset
	500	* If P.type == Reset,
	501	* Tear down connection
	502	* S.state := TIMEWAIT
	503	* Set TIMEWAIT timer
	504	* Drop packet and return
	505	*/
	506	if (dh->dccph_type == DCCP_PKT_RESET) {
7690af3f ACM	507	/*
	508	* Queue the equivalent of TCP fin so that dccp_recvmsg
	509	* exits the loop
	510	*/
7c657876 ACM	511	dccp_fin(sk, skb);
	512	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
	513	return 0;
	514	/*
	515	* Step 7: Check for unexpected packet types
	516	* If (S.is_server and P.type == CloseReq)
	517	* or (S.is_server and P.type == Response)
	518	* or (S.is_client and P.type == Request)
	519	* or (S.state == RESPOND and P.type == Data),
	520	* Send Sync packet acknowledging P.seqno
	521	* Drop packet and return
	522	*/
	523	} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
7690af3f ACM	524	(dh->dccph_type == DCCP_PKT_RESPONSE \|\|
7690af3f ACM	525	dh->dccph_type == DCCP_PKT_CLOSEREQ)) \|\|
7c657876 ACM	526	(dp->dccps_role == DCCP_ROLE_CLIENT &&
7c657876 ACM	527	dh->dccph_type == DCCP_PKT_REQUEST) \|\|
7690af3f ACM	528	(sk->sk_state == DCCP_RESPOND &&
7690af3f ACM	529	dh->dccph_type == DCCP_PKT_DATA)) {
0c10c5d9	530	dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
7c657876	531	goto discard;
7ad07e7c ACM	532	} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
	533	dccp_rcv_closereq(sk, skb);
	534	goto discard;
	535	} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
	536	dccp_rcv_close(sk, skb);
	537	return 0;
7c657876 ACM	538	}
7c657876 ACM	539
2b80230a	540	if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
0c10c5d9	541	dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
2b80230a ACM	542	goto discard;
	543	}
	544
7c657876 ACM	545	switch (sk->sk_state) {
7c657876 ACM	546	case DCCP_CLOSED:
0c10c5d9	547	dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
7c657876 ACM	548	return 1;
7c657876 ACM	549
7c657876 ACM	550	case DCCP_REQUESTING:
	551	/* FIXME: do congestion control initialization */
	552
	553	queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
	554	if (queued >= 0)
	555	return queued;
	556
	557	__kfree_skb(skb);
	558	return 0;
	559
	560	case DCCP_RESPOND:
	561	case DCCP_PARTOPEN:
7690af3f ACM	562	queued = dccp_rcv_respond_partopen_state_process(sk, skb,
7690af3f ACM	563	dh, len);
7c657876 ACM	564	break;
	565	}
	566
7690af3f ACM	567	if (dh->dccph_type == DCCP_PKT_ACK \|\|
7690af3f ACM	568	dh->dccph_type == DCCP_PKT_DATAACK) {
7c657876 ACM	569	switch (old_state) {
	570	case DCCP_PARTOPEN:
	571	sk->sk_state_change(sk);
	572	sk_wake_async(sk, 0, POLL_OUT);
	573	break;
	574	}
	575	}
	576
	577	if (!queued) {
	578	discard:
	579	__kfree_skb(skb);
	580	}
	581	return 0;
	582	}
f21e68ca ACM	583
f21e68ca ACM	584	EXPORT_SYMBOL_GPL(dccp_rcv_state_process);