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

/*
 *  net/dccp/minisocks.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/kernel.h>
#include <linux/skbuff.h>
#include <linux/timer.h>

#include <net/sock.h>
#include <net/xfrm.h>
#include <net/inet_timewait_sock.h>

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

struct inet_timewait_death_row dccp_death_row = {
	.sysctl_max_tw_buckets = NR_FILE * 2,
	.period		= DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
	.death_lock	= __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock),
	.hashinfo	= &dccp_hashinfo,
	.tw_timer	= TIMER_INITIALIZER(inet_twdr_hangman, 0,
					    (unsigned long)&dccp_death_row),
	.twkill_work	= __WORK_INITIALIZER(dccp_death_row.twkill_work,
					     inet_twdr_twkill_work),
/* Short-time timewait calendar */

	.twcal_hand	= -1,
	.twcal_timer	= TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
					    (unsigned long)&dccp_death_row),
};

EXPORT_SYMBOL_GPL(dccp_death_row);

void dccp_time_wait(struct sock *sk, int state, int timeo)
{
	struct inet_timewait_sock *tw = NULL;

	if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
		tw = inet_twsk_alloc(sk, state);

	if (tw != NULL) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
		const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
		if (tw->tw_family == PF_INET6) {
			const struct ipv6_pinfo *np = inet6_sk(sk);
			struct inet6_timewait_sock *tw6;

			tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
			tw6 = inet6_twsk((struct sock *)tw);
			ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
			ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
			tw->tw_ipv6only = np->ipv6only;
		}
#endif
		/* Linkage updates. */
		__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);

		/* Get the TIME_WAIT timeout firing. */
		if (timeo < rto)
			timeo = rto;

		tw->tw_timeout = DCCP_TIMEWAIT_LEN;
		if (state == DCCP_TIME_WAIT)
			timeo = DCCP_TIMEWAIT_LEN;

		inet_twsk_schedule(tw, &dccp_death_row, timeo,
				   DCCP_TIMEWAIT_LEN);
		inet_twsk_put(tw);
	} else {
		/* Sorry, if we're out of memory, just CLOSE this
		 * socket up.  We've got bigger problems than
		 * non-graceful socket closings.
		 */
		DCCP_WARN("time wait bucket table overflow\n");
	}

	dccp_done(sk);
}

struct sock *dccp_create_openreq_child(struct sock *sk,
				       const struct request_sock *req,
				       const struct sk_buff *skb)
{
	/*
	 * Step 3: Process LISTEN state
	 *
	 *   (* Generate a new socket and switch to that socket *)
	 *   Set S := new socket for this port pair
	 */
	struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);

	if (newsk != NULL) {
		const struct dccp_request_sock *dreq = dccp_rsk(req);
		struct inet_connection_sock *newicsk = inet_csk(newsk);
		struct dccp_sock *newdp = dccp_sk(newsk);
		struct dccp_minisock *newdmsk = dccp_msk(newsk);

		newdp->dccps_role	   = DCCP_ROLE_SERVER;
		newdp->dccps_hc_rx_ackvec  = NULL;
		newdp->dccps_service_list  = NULL;
		newdp->dccps_service	   = dreq->dreq_service;
		newicsk->icsk_rto	   = DCCP_TIMEOUT_INIT;
		do_gettimeofday(&newdp->dccps_epoch);

		if (dccp_feat_clone(sk, newsk))
			goto out_free;

		if (newdmsk->dccpms_send_ack_vector) {
			newdp->dccps_hc_rx_ackvec =
						dccp_ackvec_alloc(GFP_ATOMIC);
			if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
				goto out_free;
		}

		newdp->dccps_hc_rx_ccid =
			    ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
					   newsk, GFP_ATOMIC);
		newdp->dccps_hc_tx_ccid =
			    ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
					   newsk, GFP_ATOMIC);
		if (unlikely(newdp->dccps_hc_rx_ccid == NULL ||
			     newdp->dccps_hc_tx_ccid == NULL)) {
			dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
			ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
			ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
out_free:
			/* It is still raw copy of parent, so invalidate
			 * destructor and make plain sk_free() */
			newsk->sk_destruct = NULL;
			sk_free(newsk);
			return NULL;
		}

		/*
		 * Step 3: Process LISTEN state
		 *
		 *    Choose S.ISS (initial seqno) or set from Init Cookies
		 *    Initialize S.GAR := S.ISS
		 *    Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
		 */

		/* See dccp_v4_conn_request */
		newdmsk->dccpms_sequence_window = req->rcv_wnd;

		newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
		dccp_update_gsr(newsk, dreq->dreq_isr);

		newdp->dccps_iss = dreq->dreq_iss;
		dccp_update_gss(newsk, dreq->dreq_iss);

		/*
		 * 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.
		 */
		dccp_set_seqno(&newdp->dccps_swl,
			       max48(newdp->dccps_swl, newdp->dccps_isr));
		dccp_set_seqno(&newdp->dccps_awl,
			       max48(newdp->dccps_awl, newdp->dccps_iss));

		dccp_init_xmit_timers(newsk);

		DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
	}
	return newsk;
}

EXPORT_SYMBOL_GPL(dccp_create_openreq_child);

/*
 * Process an incoming packet for RESPOND sockets represented
 * as an request_sock.
 */
struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
			    struct request_sock *req,
			    struct request_sock **prev)
{
	struct sock *child = NULL;

	/* Check for retransmitted REQUEST */
	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
		struct dccp_request_sock *dreq = dccp_rsk(req);

		if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
			dccp_pr_debug("Retransmitted REQUEST\n");
			dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
			/*
			 * Send another RESPONSE packet
			 * To protect against Request floods, increment retrans
			 * counter (backoff, monitored by dccp_response_timer).
			 */
			req->retrans++;
			req->rsk_ops->rtx_syn_ack(sk, req, NULL);
		}
		/* Network Duplicate, discard packet */
		return NULL;
	}

	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;

	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
	    dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
		goto drop;

	/* Invalid ACK */
	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
		dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
			      "dreq_iss=%llu\n",
			      (unsigned long long)
			      DCCP_SKB_CB(skb)->dccpd_ack_seq,
			      (unsigned long long)
			      dccp_rsk(req)->dreq_iss);
		goto drop;
	}

	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
	if (child == NULL)
		goto listen_overflow;

	/* FIXME: deal with options */

	inet_csk_reqsk_queue_unlink(sk, req, prev);
	inet_csk_reqsk_queue_removed(sk, req);
	inet_csk_reqsk_queue_add(sk, req, child);
out:
	return child;
listen_overflow:
	dccp_pr_debug("listen_overflow!\n");
	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
drop:
	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
		req->rsk_ops->send_reset(sk, skb);

	inet_csk_reqsk_queue_drop(sk, req, prev);
	goto out;
}

EXPORT_SYMBOL_GPL(dccp_check_req);

/*
 *  Queue segment on the new socket if the new socket is active,
 *  otherwise we just shortcircuit this and continue with
 *  the new socket.
 */
int dccp_child_process(struct sock *parent, struct sock *child,
		       struct sk_buff *skb)
{
	int ret = 0;
	const int state = child->sk_state;

	if (!sock_owned_by_user(child)) {
		ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
					     skb->len);

		/* Wakeup parent, send SIGIO */
		if (state == DCCP_RESPOND && child->sk_state != state)
			parent->sk_data_ready(parent, 0);
	} else {
		/* Alas, it is possible again, because we do lookup
		 * in main socket hash table and lock on listening
		 * socket does not protect us more.
		 */
		sk_add_backlog(child, skb);
	}

	bh_unlock_sock(child);
	sock_put(child);
	return ret;
}

EXPORT_SYMBOL_GPL(dccp_child_process);

void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk)
{
	DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
}

EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);

void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
{
	inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
	inet_rsk(req)->acked	= 0;
	req->rcv_wnd		= sysctl_dccp_feat_sequence_window;
}

EXPORT_SYMBOL_GPL(dccp_reqsk_init);
Commit	Line	Data
7c657876 ACM	1	/*
	2	* net/dccp/minisocks.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	13	#include <linux/dccp.h>
8a73cd09	14	#include <linux/kernel.h>
7c657876 ACM	15	#include <linux/skbuff.h>
	16	#include <linux/timer.h>
	17
	18	#include <net/sock.h>
	19	#include <net/xfrm.h>
	20	#include <net/inet_timewait_sock.h>
	21
ae31c339	22	#include "ackvec.h"
7c657876 ACM	23	#include "ccid.h"
7c657876 ACM	24	#include "dccp.h"
afe00251	25	#include "feat.h"
7c657876	26
64cf1e5d ACM	27	struct inet_timewait_death_row dccp_death_row = {
	28	.sysctl_max_tw_buckets = NR_FILE * 2,
	29	.period = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
4ef8d0ae	30	.death_lock = __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock),
64cf1e5d ACM	31	.hashinfo = &dccp_hashinfo,
	32	.tw_timer = TIMER_INITIALIZER(inet_twdr_hangman, 0,
	33	(unsigned long)&dccp_death_row),
	34	.twkill_work = __WORK_INITIALIZER(dccp_death_row.twkill_work,
c4028958	35	inet_twdr_twkill_work),
64cf1e5d ACM	36	/* Short-time timewait calendar */
	37
	38	.twcal_hand = -1,
	39	.twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
	40	(unsigned long)&dccp_death_row),
	41	};
	42
f21e68ca ACM	43	EXPORT_SYMBOL_GPL(dccp_death_row);
f21e68ca ACM	44
7c657876 ACM	45	void dccp_time_wait(struct sock *sk, int state, int timeo)
7c657876 ACM	46	{
64cf1e5d	47	struct inet_timewait_sock *tw = NULL;
7c657876	48
64cf1e5d ACM	49	if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
	50	tw = inet_twsk_alloc(sk, state);
	51
	52	if (tw != NULL) {
	53	const struct inet_connection_sock *icsk = inet_csk(sk);
	54	const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
3df80d93 ACM	55	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	56	if (tw->tw_family == PF_INET6) {
	57	const struct ipv6_pinfo *np = inet6_sk(sk);
	58	struct inet6_timewait_sock *tw6;
64cf1e5d	59
3df80d93 ACM	60	tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
	61	tw6 = inet6_twsk((struct sock *)tw);
	62	ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
	63	ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
	64	tw->tw_ipv6only = np->ipv6only;
	65	}
	66	#endif
64cf1e5d ACM	67	/* Linkage updates. */
	68	__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
	69
	70	/* Get the TIME_WAIT timeout firing. */
	71	if (timeo < rto)
	72	timeo = rto;
	73
	74	tw->tw_timeout = DCCP_TIMEWAIT_LEN;
	75	if (state == DCCP_TIME_WAIT)
	76	timeo = DCCP_TIMEWAIT_LEN;
	77
	78	inet_twsk_schedule(tw, &dccp_death_row, timeo,
	79	DCCP_TIMEWAIT_LEN);
	80	inet_twsk_put(tw);
	81	} else {
	82	/* Sorry, if we're out of memory, just CLOSE this
	83	* socket up. We've got bigger problems than
	84	* non-graceful socket closings.
	85	*/
59348b19	86	DCCP_WARN("time wait bucket table overflow\n");
64cf1e5d ACM	87	}
	88
	89	dccp_done(sk);
7c657876 ACM	90	}
	91
	92	struct sock dccp_create_openreq_child(struct sock sk,
	93	const struct request_sock *req,
	94	const struct sk_buff *skb)
	95	{
	96	/*
	97	* Step 3: Process LISTEN state
	98	*
d83ca5ac GR	99	* (* Generate a new socket and switch to that socket *)
d83ca5ac GR	100	* Set S := new socket for this port pair
7c657876 ACM	101	*/
	102	struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
	103
	104	if (newsk != NULL) {
	105	const struct dccp_request_sock *dreq = dccp_rsk(req);
99c72ce0	106	struct inet_connection_sock *newicsk = inet_csk(newsk);
7c657876	107	struct dccp_sock *newdp = dccp_sk(newsk);
a4bf3902	108	struct dccp_minisock *newdmsk = dccp_msk(newsk);
7c657876	109
67e6b629	110	newdp->dccps_role = DCCP_ROLE_SERVER;
ae31c339	111	newdp->dccps_hc_rx_ackvec = NULL;
67e6b629 ACM	112	newdp->dccps_service_list = NULL;
	113	newdp->dccps_service = dreq->dreq_service;
	114	newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
b0e56780	115	do_gettimeofday(&newdp->dccps_epoch);
7c657876	116
afe00251 AB	117	if (dccp_feat_clone(sk, newsk))
	118	goto out_free;
	119
a4bf3902	120	if (newdmsk->dccpms_send_ack_vector) {
ae31c339	121	newdp->dccps_hc_rx_ackvec =
7400d781	122	dccp_ackvec_alloc(GFP_ATOMIC);
ae31c339	123	if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
7c657876 ACM	124	goto out_free;
	125	}
	126
91f0ebf7	127	newdp->dccps_hc_rx_ccid =
a4bf3902	128	ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
91f0ebf7 ACM	129	newsk, GFP_ATOMIC);
91f0ebf7 ACM	130	newdp->dccps_hc_tx_ccid =
a4bf3902	131	ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
91f0ebf7 ACM	132	newsk, GFP_ATOMIC);
	133	if (unlikely(newdp->dccps_hc_rx_ccid == NULL \|\|
	134	newdp->dccps_hc_tx_ccid == NULL)) {
ae31c339	135	dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
91f0ebf7 ACM	136	ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
91f0ebf7 ACM	137	ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
7c657876 ACM	138	out_free:
	139	/* It is still raw copy of parent, so invalidate
	140	* destructor and make plain sk_free() */
	141	newsk->sk_destruct = NULL;
	142	sk_free(newsk);
	143	return NULL;
	144	}
	145
7c657876 ACM	146	/*
	147	* Step 3: Process LISTEN state
	148	*
d83ca5ac GR	149	* Choose S.ISS (initial seqno) or set from Init Cookies
	150	* Initialize S.GAR := S.ISS
	151	* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
7c657876 ACM	152	*/
	153
	154	/* See dccp_v4_conn_request */
a4bf3902	155	newdmsk->dccpms_sequence_window = req->rcv_wnd;
7c657876 ACM	156
	157	newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
	158	dccp_update_gsr(newsk, dreq->dreq_isr);
	159
	160	newdp->dccps_iss = dreq->dreq_iss;
	161	dccp_update_gss(newsk, dreq->dreq_iss);
	162
03ace394 ACM	163	/*
	164	* SWL and AWL are initially adjusted so that they are not less than
	165	* the initial Sequence Numbers received and sent, respectively:
	166	* SWL := max(GSR + 1 - floor(W/4), ISR),
	167	* AWL := max(GSS - W' + 1, ISS).
	168	* These adjustments MUST be applied only at the beginning of the
	169	* connection.
	170	*/
	171	dccp_set_seqno(&newdp->dccps_swl,
	172	max48(newdp->dccps_swl, newdp->dccps_isr));
	173	dccp_set_seqno(&newdp->dccps_awl,
	174	max48(newdp->dccps_awl, newdp->dccps_iss));
	175
7c657876 ACM	176	dccp_init_xmit_timers(newsk);
	177
	178	DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
	179	}
	180	return newsk;
	181	}
	182
f21e68ca ACM	183	EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
f21e68ca ACM	184
8109b02b	185	/*
7c657876 ACM	186	* Process an incoming packet for RESPOND sockets represented
	187	* as an request_sock.
	188	*/
	189	struct sock dccp_check_req(struct sock sk, struct sk_buff *skb,
	190	struct request_sock *req,
	191	struct request_sock **prev)
	192	{
	193	struct sock *child = NULL;
	194
	195	/* Check for retransmitted REQUEST */
	196	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
e11d9d30	197	struct dccp_request_sock *dreq = dccp_rsk(req);
7c657876	198
e11d9d30	199	if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
7c657876	200	dccp_pr_debug("Retransmitted REQUEST\n");
e11d9d30 GR	201	dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
	202	/*
	203	* Send another RESPONSE packet
	204	* To protect against Request floods, increment retrans
	205	* counter (backoff, monitored by dccp_response_timer).
	206	*/
	207	req->retrans++;
7c657876 ACM	208	req->rsk_ops->rtx_syn_ack(sk, req, NULL);
	209	}
	210	/* Network Duplicate, discard packet */
	211	return NULL;
	212	}
	213
	214	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	215
	216	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
	217	dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
	218	goto drop;
	219
	220	/* Invalid ACK */
	221	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
7690af3f ACM	222	dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
7690af3f ACM	223	"dreq_iss=%llu\n",
f6ccf554 DM	224	(unsigned long long)
	225	DCCP_SKB_CB(skb)->dccpd_ack_seq,
	226	(unsigned long long)
	227	dccp_rsk(req)->dreq_iss);
7c657876 ACM	228	goto drop;
	229	}
	230
57cca05a	231	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
7c657876 ACM	232	if (child == NULL)
	233	goto listen_overflow;
	234
	235	/* FIXME: deal with options */
	236
	237	inet_csk_reqsk_queue_unlink(sk, req, prev);
	238	inet_csk_reqsk_queue_removed(sk, req);
	239	inet_csk_reqsk_queue_add(sk, req, child);
	240	out:
	241	return child;
	242	listen_overflow:
	243	dccp_pr_debug("listen_overflow!\n");
	244	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
	245	drop:
	246	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
cfb6eeb4	247	req->rsk_ops->send_reset(sk, skb);
7c657876 ACM	248
	249	inet_csk_reqsk_queue_drop(sk, req, prev);
	250	goto out;
	251	}
	252
f21e68ca ACM	253	EXPORT_SYMBOL_GPL(dccp_check_req);
f21e68ca ACM	254
7c657876 ACM	255	/*
	256	* Queue segment on the new socket if the new socket is active,
	257	* otherwise we just shortcircuit this and continue with
	258	* the new socket.
	259	*/
	260	int dccp_child_process(struct sock parent, struct sock child,
	261	struct sk_buff *skb)
	262	{
	263	int ret = 0;
	264	const int state = child->sk_state;
	265
	266	if (!sock_owned_by_user(child)) {
7690af3f ACM	267	ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
7690af3f ACM	268	skb->len);
7c657876 ACM	269
	270	/* Wakeup parent, send SIGIO */
	271	if (state == DCCP_RESPOND && child->sk_state != state)
	272	parent->sk_data_ready(parent, 0);
	273	} else {
	274	/* Alas, it is possible again, because we do lookup
	275	* in main socket hash table and lock on listening
	276	* socket does not protect us more.
	277	*/
	278	sk_add_backlog(child, skb);
	279	}
	280
	281	bh_unlock_sock(child);
	282	sock_put(child);
	283	return ret;
	284	}
f21e68ca ACM	285
f21e68ca ACM	286	EXPORT_SYMBOL_GPL(dccp_child_process);
8a73cd09 GR	287
	288	void dccp_reqsk_send_ack(struct sk_buff skb, struct request_sock rsk)
	289	{
59348b19	290	DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
8a73cd09 GR	291	}
	292
	293	EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
cf557926 GR	294
	295	void dccp_reqsk_init(struct request_sock req, struct sk_buff skb)
	296	{
	297	inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
	298	inet_rsk(req)->acked = 0;
afb0a34d	299	req->rcv_wnd = sysctl_dccp_feat_sequence_window;
cf557926 GR	300	}
	301
	302	EXPORT_SYMBOL_GPL(dccp_reqsk_init);