[GitHub/mt8127/android_kernel_alcatel_ttab.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_v4_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 inline 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;
}

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);

	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;
}

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;
		}

		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));

		if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
		    ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
			ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
			ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
			/* FIXME: send appropriate RESET code */
			goto out_invalid_packet;
		}

		dccp_sync_mss(sk, dp->dccps_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);

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

	/*
	 *  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;
}
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	{
7ad07e7c ACM	35	dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED);
	36	dccp_fin(sk, skb);
	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	}
	58
	59	static inline void dccp_event_ack_recv(struct sock sk, struct sk_buff skb)
	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
	154	int dccp_rcv_established(struct sock sk, struct sk_buff skb,
	155	const struct dccp_hdr *dh, const unsigned len)
	156	{
	157	struct dccp_sock *dp = dccp_sk(sk);
	158
	159	if (dccp_check_seqno(sk, skb))
	160	goto discard;
	161
	162	if (dccp_parse_options(sk, skb))
	163	goto discard;
	164
	165	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
	166	dccp_event_ack_recv(sk, skb);
	167
ae31c339 ACM	168	if (dp->dccps_options.dccpo_send_ack_vector &&
	169	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	170	DCCP_SKB_CB(skb)->dccpd_seq,
	171	DCCP_ACKVEC_STATE_RECEIVED))
	172	goto discard;
7c657876 ACM	173
	174	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	175	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
	176
	177	switch (dccp_hdr(skb)->dccph_type) {
	178	case DCCP_PKT_DATAACK:
	179	case DCCP_PKT_DATA:
	180	/*
7690af3f ACM	181	* FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
7690af3f ACM	182	* option if it is.
7c657876 ACM	183	*/
	184	__skb_pull(skb, dh->dccph_doff * 4);
	185	__skb_queue_tail(&sk->sk_receive_queue, skb);
	186	skb_set_owner_r(skb, sk);
	187	sk->sk_data_ready(sk, 0);
	188	return 0;
	189	case DCCP_PKT_ACK:
	190	goto discard;
	191	case DCCP_PKT_RESET:
	192	/*
	193	* Step 9: Process Reset
	194	* If P.type == Reset,
	195	* Tear down connection
	196	* S.state := TIMEWAIT
	197	* Set TIMEWAIT timer
	198	* Drop packet and return
	199	*/
	200	dccp_fin(sk, skb);
	201	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
	202	return 0;
	203	case DCCP_PKT_CLOSEREQ:
	204	dccp_rcv_closereq(sk, skb);
	205	goto discard;
	206	case DCCP_PKT_CLOSE:
	207	dccp_rcv_close(sk, skb);
	208	return 0;
	209	case DCCP_PKT_REQUEST:
	210	/* Step 7
	211	* or (S.is_server and P.type == Response)
	212	* or (S.is_client and P.type == Request)
	213	* or (S.state >= OPEN and P.type == Request
	214	* and P.seqno >= S.OSR)
	215	* or (S.state >= OPEN and P.type == Response
	216	* and P.seqno >= S.OSR)
	217	* or (S.state == RESPOND and P.type == Data),
	218	* Send Sync packet acknowledging P.seqno
	219	* Drop packet and return
	220	*/
	221	if (dp->dccps_role != DCCP_ROLE_LISTEN)
	222	goto send_sync;
	223	goto check_seq;
	224	case DCCP_PKT_RESPONSE:
	225	if (dp->dccps_role != DCCP_ROLE_CLIENT)
	226	goto send_sync;
	227	check_seq:
	228	if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
	229	send_sync:
e92ae93a ACM	230	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
e92ae93a ACM	231	DCCP_PKT_SYNC);
7c657876 ACM	232	}
7c657876 ACM	233	break;
e92ae93a ACM	234	case DCCP_PKT_SYNC:
	235	dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
	236	DCCP_PKT_SYNCACK);
	237	/*
	238	* From the draft:
	239	*
	240	* As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
	241	* MAY have non-zero-length application data areas, whose
	242	* contents * receivers MUST ignore.
	243	*/
	244	goto discard;
7c657876 ACM	245	}
	246
	247	DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
	248	discard:
	249	__kfree_skb(skb);
	250	return 0;
	251	}
	252
	253	static int dccp_rcv_request_sent_state_process(struct sock *sk,
	254	struct sk_buff *skb,
	255	const struct dccp_hdr *dh,
	256	const unsigned len)
	257	{
	258	/*
	259	* Step 4: Prepare sequence numbers in REQUEST
	260	* If S.state == REQUEST,
	261	* If (P.type == Response or P.type == Reset)
	262	* and S.AWL <= P.ackno <= S.AWH,
	263	* / * Set sequence number variables corresponding to the
	264	* other endpoint, so P will pass the tests in Step 6 * /
	265	* Set S.GSR, S.ISR, S.SWL, S.SWH
	266	* / * Response processing continues in Step 10; Reset
	267	* processing continues in Step 9 * /
	268	*/
	269	if (dh->dccph_type == DCCP_PKT_RESPONSE) {
	270	const struct inet_connection_sock *icsk = inet_csk(sk);
	271	struct dccp_sock *dp = dccp_sk(sk);
	272
	273	/* Stop the REQUEST timer */
	274	inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
	275	BUG_TRAP(sk->sk_send_head != NULL);
	276	__kfree_skb(sk->sk_send_head);
	277	sk->sk_send_head = NULL;
	278
7690af3f ACM	279	if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
	280	dp->dccps_awl, dp->dccps_awh)) {
	281	dccp_pr_debug("invalid ackno: S.AWL=%llu, "
	282	"P.ackno=%llu, S.AWH=%llu \n",
	283	(unsigned long long)dp->dccps_awl,
	284	(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
	285	(unsigned long long)dp->dccps_awh);
7c657876 ACM	286	goto out_invalid_packet;
	287	}
	288
	289	dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
03ace394 ACM	290	dccp_update_gsr(sk, dp->dccps_isr);
	291	/*
	292	* SWL and AWL are initially adjusted so that they are not less than
	293	* the initial Sequence Numbers received and sent, respectively:
	294	* SWL := max(GSR + 1 - floor(W/4), ISR),
	295	* AWL := max(GSS - W' + 1, ISS).
	296	* These adjustments MUST be applied only at the beginning of the
	297	* connection.
	298	*
	299	* AWL was adjusted in dccp_v4_connect -acme
	300	*/
	301	dccp_set_seqno(&dp->dccps_swl,
	302	max48(dp->dccps_swl, dp->dccps_isr));
7c657876 ACM	303
	304	if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 \|\|
	305	ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
	306	ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
	307	ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
	308	/* FIXME: send appropriate RESET code */
	309	goto out_invalid_packet;
	310	}
	311
	312	dccp_sync_mss(sk, dp->dccps_pmtu_cookie);
	313
	314	/*
	315	* Step 10: Process REQUEST state (second part)
	316	* If S.state == REQUEST,
7690af3f ACM	317	* / * If we get here, P is a valid Response from the
	318	* server (see Step 4), and we should move to
	319	* PARTOPEN state. PARTOPEN means send an Ack,
	320	* don't send Data packets, retransmit Acks
	321	* periodically, and always include any Init Cookie
	322	* from the Response * /
7c657876 ACM	323	* S.state := PARTOPEN
	324	* Set PARTOPEN timer
	325	* Continue with S.state == PARTOPEN
7690af3f ACM	326	* / * Step 12 will send the Ack completing the
7690af3f ACM	327	* three-way handshake * /
7c657876 ACM	328	*/
	329	dccp_set_state(sk, DCCP_PARTOPEN);
	330
	331	/* Make sure socket is routed, for correct metrics. */
57cca05a	332	icsk->icsk_af_ops->rebuild_header(sk);
7c657876 ACM	333
	334	if (!sock_flag(sk, SOCK_DEAD)) {
	335	sk->sk_state_change(sk);
	336	sk_wake_async(sk, 0, POLL_OUT);
	337	}
	338
	339	if (sk->sk_write_pending \|\| icsk->icsk_ack.pingpong \|\|
	340	icsk->icsk_accept_queue.rskq_defer_accept) {
	341	/* Save one ACK. Data will be ready after
	342	* several ticks, if write_pending is set.
	343	*
	344	* It may be deleted, but with this feature tcpdumps
	345	* look so _wonderfully_ clever, that I was not able
	346	* to stand against the temptation 8) --ANK
	347	*/
	348	/*
	349	* OK, in DCCP we can as well do a similar trick, its
	350	* even in the draft, but there is no need for us to
	351	* schedule an ack here, as dccp_sendmsg does this for
	352	* us, also stated in the draft. -acme
	353	*/
	354	__kfree_skb(skb);
	355	return 0;
	356	}
	357	dccp_send_ack(sk);
	358	return -1;
	359	}
	360
	361	out_invalid_packet:
0c10c5d9 ACM	362	/* dccp_v4_do_rcv will send a reset */
	363	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	364	return 1;
7c657876 ACM	365	}
	366
	367	static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
	368	struct sk_buff *skb,
	369	const struct dccp_hdr *dh,
	370	const unsigned len)
	371	{
	372	int queued = 0;
	373
	374	switch (dh->dccph_type) {
	375	case DCCP_PKT_RESET:
	376	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
	377	break;
2a9bc9bb ACM	378	case DCCP_PKT_DATA:
	379	if (sk->sk_state == DCCP_RESPOND)
	380	break;
7c657876 ACM	381	case DCCP_PKT_DATAACK:
	382	case DCCP_PKT_ACK:
	383	/*
7690af3f ACM	384	* FIXME: we should be reseting the PARTOPEN (DELACK) timer
	385	* here but only if we haven't used the DELACK timer for
	386	* something else, like sending a delayed ack for a TIMESTAMP
	387	* echo, etc, for now were not clearing it, sending an extra
	388	* ACK when there is nothing else to do in DELACK is not a big
	389	* deal after all.
7c657876 ACM	390	*/
	391
	392	/* Stop the PARTOPEN timer */
	393	if (sk->sk_state == DCCP_PARTOPEN)
	394	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
	395
	396	dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
	397	dccp_set_state(sk, DCCP_OPEN);
	398
2a9bc9bb ACM	399	if (dh->dccph_type == DCCP_PKT_DATAACK \|\|
2a9bc9bb ACM	400	dh->dccph_type == DCCP_PKT_DATA) {
7c657876	401	dccp_rcv_established(sk, skb, dh, len);
7690af3f ACM	402	queued = 1; /* packet was queued
7690af3f ACM	403	(by dccp_rcv_established) */
7c657876 ACM	404	}
	405	break;
	406	}
	407
	408	return queued;
	409	}
	410
	411	int dccp_rcv_state_process(struct sock sk, struct sk_buff skb,
	412	struct dccp_hdr *dh, unsigned len)
	413	{
	414	struct dccp_sock *dp = dccp_sk(sk);
0c10c5d9	415	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
7c657876 ACM	416	const int old_state = sk->sk_state;
	417	int queued = 0;
	418
8649b0d4 ACM	419	/*
	420	* Step 3: Process LISTEN state
	421	* (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
	422	*
	423	* If S.state == LISTEN,
	424	* If P.type == Request or P contains a valid Init Cookie
	425	* option,
	426	* * Must scan the packet's options to check for an Init
	427	* Cookie. Only the Init Cookie is processed here,
	428	* however; other options are processed in Step 8. This
	429	* scan need only be performed if the endpoint uses Init
	430	* Cookies *
	431	* * Generate a new socket and switch to that socket *
	432	* Set S := new socket for this port pair
	433	* S.state = RESPOND
	434	* Choose S.ISS (initial seqno) or set from Init Cookie
	435	* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
	436	* Continue with S.state == RESPOND
	437	* * A Response packet will be generated in Step 11 *
	438	* Otherwise,
	439	* Generate Reset(No Connection) unless P.type == Reset
	440	* Drop packet and return
	441	*
	442	* NOTE: the check for the packet types is done in
	443	* dccp_rcv_state_process
	444	*/
	445	if (sk->sk_state == DCCP_LISTEN) {
	446	if (dh->dccph_type == DCCP_PKT_REQUEST) {
57cca05a ACM	447	if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
57cca05a ACM	448	skb) < 0)
8649b0d4 ACM	449	return 1;
	450
	451	/* FIXME: do congestion control initialization */
	452	goto discard;
	453	}
	454	if (dh->dccph_type == DCCP_PKT_RESET)
	455	goto discard;
	456
0c10c5d9 ACM	457	/* Caller (dccp_v4_do_rcv) will send Reset */
0c10c5d9 ACM	458	dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
8649b0d4 ACM	459	return 1;
	460	}
	461
	462	if (sk->sk_state != DCCP_REQUESTING) {
7c657876 ACM	463	if (dccp_check_seqno(sk, skb))
	464	goto discard;
	465
	466	/*
	467	* Step 8: Process options and mark acknowledgeable
	468	*/
	469	if (dccp_parse_options(sk, skb))
	470	goto discard;
	471
0c10c5d9	472	if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
7c657876 ACM	473	dccp_event_ack_recv(sk, skb);
	474
	475	ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
	476	ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
	477
ae31c339 ACM	478	if (dp->dccps_options.dccpo_send_ack_vector &&
	479	dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
	480	DCCP_SKB_CB(skb)->dccpd_seq,
	481	DCCP_ACKVEC_STATE_RECEIVED))
	482	goto discard;
7c657876 ACM	483	}
	484
	485	/*
	486	* Step 9: Process Reset
	487	* If P.type == Reset,
	488	* Tear down connection
	489	* S.state := TIMEWAIT
	490	* Set TIMEWAIT timer
	491	* Drop packet and return
	492	*/
	493	if (dh->dccph_type == DCCP_PKT_RESET) {
7690af3f ACM	494	/*
	495	* Queue the equivalent of TCP fin so that dccp_recvmsg
	496	* exits the loop
	497	*/
7c657876 ACM	498	dccp_fin(sk, skb);
	499	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
	500	return 0;
	501	/*
	502	* Step 7: Check for unexpected packet types
	503	* If (S.is_server and P.type == CloseReq)
	504	* or (S.is_server and P.type == Response)
	505	* or (S.is_client and P.type == Request)
	506	* or (S.state == RESPOND and P.type == Data),
	507	* Send Sync packet acknowledging P.seqno
	508	* Drop packet and return
	509	*/
	510	} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
7690af3f ACM	511	(dh->dccph_type == DCCP_PKT_RESPONSE \|\|
7690af3f ACM	512	dh->dccph_type == DCCP_PKT_CLOSEREQ)) \|\|
7c657876 ACM	513	(dp->dccps_role == DCCP_ROLE_CLIENT &&
7c657876 ACM	514	dh->dccph_type == DCCP_PKT_REQUEST) \|\|
7690af3f ACM	515	(sk->sk_state == DCCP_RESPOND &&
7690af3f ACM	516	dh->dccph_type == DCCP_PKT_DATA)) {
0c10c5d9	517	dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
7c657876	518	goto discard;
7ad07e7c ACM	519	} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
	520	dccp_rcv_closereq(sk, skb);
	521	goto discard;
	522	} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
	523	dccp_rcv_close(sk, skb);
	524	return 0;
7c657876 ACM	525	}
7c657876 ACM	526
2b80230a	527	if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
0c10c5d9	528	dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
2b80230a ACM	529	goto discard;
	530	}
	531
7c657876 ACM	532	switch (sk->sk_state) {
7c657876 ACM	533	case DCCP_CLOSED:
0c10c5d9	534	dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
7c657876 ACM	535	return 1;
7c657876 ACM	536
7c657876 ACM	537	case DCCP_REQUESTING:
	538	/* FIXME: do congestion control initialization */
	539
	540	queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
	541	if (queued >= 0)
	542	return queued;
	543
	544	__kfree_skb(skb);
	545	return 0;
	546
	547	case DCCP_RESPOND:
	548	case DCCP_PARTOPEN:
7690af3f ACM	549	queued = dccp_rcv_respond_partopen_state_process(sk, skb,
7690af3f ACM	550	dh, len);
7c657876 ACM	551	break;
	552	}
	553
7690af3f ACM	554	if (dh->dccph_type == DCCP_PKT_ACK \|\|
7690af3f ACM	555	dh->dccph_type == DCCP_PKT_DATAACK) {
7c657876 ACM	556	switch (old_state) {
	557	case DCCP_PARTOPEN:
	558	sk->sk_state_change(sk);
	559	sk_wake_async(sk, 0, POLL_OUT);
	560	break;
	561	}
	562	}
	563
	564	if (!queued) {
	565	discard:
	566	__kfree_skb(skb);
	567	}
	568	return 0;
	569	}