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

/*
 *  net/dccp/minisocks.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/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_minisock_init(struct dccp_minisock *dmsk)
{
	dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
	dmsk->dccpms_rx_ccid	     = sysctl_dccp_feat_rx_ccid;
	dmsk->dccpms_tx_ccid	     = sysctl_dccp_feat_tx_ccid;
	dmsk->dccpms_ack_ratio	     = sysctl_dccp_feat_ack_ratio;
	dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
	dmsk->dccpms_send_ndp_count  = sysctl_dccp_feat_send_ndp_count;
}

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;

		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 <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
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
451bc047 GR	45	void dccp_minisock_init(struct dccp_minisock *dmsk)
	46	{
	47	dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
	48	dmsk->dccpms_rx_ccid = sysctl_dccp_feat_rx_ccid;
	49	dmsk->dccpms_tx_ccid = sysctl_dccp_feat_tx_ccid;
	50	dmsk->dccpms_ack_ratio = sysctl_dccp_feat_ack_ratio;
	51	dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
	52	dmsk->dccpms_send_ndp_count = sysctl_dccp_feat_send_ndp_count;
	53	}
	54
7c657876 ACM	55	void dccp_time_wait(struct sock *sk, int state, int timeo)
7c657876 ACM	56	{
64cf1e5d	57	struct inet_timewait_sock *tw = NULL;
7c657876	58
64cf1e5d ACM	59	if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
	60	tw = inet_twsk_alloc(sk, state);
	61
	62	if (tw != NULL) {
	63	const struct inet_connection_sock *icsk = inet_csk(sk);
	64	const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
3df80d93 ACM	65	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	66	if (tw->tw_family == PF_INET6) {
	67	const struct ipv6_pinfo *np = inet6_sk(sk);
	68	struct inet6_timewait_sock *tw6;
64cf1e5d	69
3df80d93 ACM	70	tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
	71	tw6 = inet6_twsk((struct sock *)tw);
	72	ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
	73	ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
	74	tw->tw_ipv6only = np->ipv6only;
	75	}
	76	#endif
64cf1e5d ACM	77	/* Linkage updates. */
	78	__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
	79
	80	/* Get the TIME_WAIT timeout firing. */
	81	if (timeo < rto)
	82	timeo = rto;
	83
	84	tw->tw_timeout = DCCP_TIMEWAIT_LEN;
	85	if (state == DCCP_TIME_WAIT)
	86	timeo = DCCP_TIMEWAIT_LEN;
	87
	88	inet_twsk_schedule(tw, &dccp_death_row, timeo,
	89	DCCP_TIMEWAIT_LEN);
	90	inet_twsk_put(tw);
	91	} else {
	92	/* Sorry, if we're out of memory, just CLOSE this
	93	* socket up. We've got bigger problems than
	94	* non-graceful socket closings.
	95	*/
59348b19	96	DCCP_WARN("time wait bucket table overflow\n");
64cf1e5d ACM	97	}
	98
	99	dccp_done(sk);
7c657876 ACM	100	}
	101
	102	struct sock dccp_create_openreq_child(struct sock sk,
	103	const struct request_sock *req,
	104	const struct sk_buff *skb)
	105	{
	106	/*
	107	* Step 3: Process LISTEN state
	108	*
d83ca5ac GR	109	* (* Generate a new socket and switch to that socket *)
d83ca5ac GR	110	* Set S := new socket for this port pair
7c657876 ACM	111	*/
	112	struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
	113
	114	if (newsk != NULL) {
	115	const struct dccp_request_sock *dreq = dccp_rsk(req);
99c72ce0	116	struct inet_connection_sock *newicsk = inet_csk(newsk);
7c657876	117	struct dccp_sock *newdp = dccp_sk(newsk);
a4bf3902	118	struct dccp_minisock *newdmsk = dccp_msk(newsk);
7c657876	119
67e6b629	120	newdp->dccps_role = DCCP_ROLE_SERVER;
ae31c339	121	newdp->dccps_hc_rx_ackvec = NULL;
67e6b629 ACM	122	newdp->dccps_service_list = NULL;
	123	newdp->dccps_service = dreq->dreq_service;
	124	newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
7c657876	125
afe00251 AB	126	if (dccp_feat_clone(sk, newsk))
	127	goto out_free;
	128
a4bf3902	129	if (newdmsk->dccpms_send_ack_vector) {
ae31c339	130	newdp->dccps_hc_rx_ackvec =
7400d781	131	dccp_ackvec_alloc(GFP_ATOMIC);
ae31c339	132	if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
7c657876 ACM	133	goto out_free;
	134	}
	135
91f0ebf7	136	newdp->dccps_hc_rx_ccid =
a4bf3902	137	ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
91f0ebf7 ACM	138	newsk, GFP_ATOMIC);
91f0ebf7 ACM	139	newdp->dccps_hc_tx_ccid =
a4bf3902	140	ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
91f0ebf7 ACM	141	newsk, GFP_ATOMIC);
	142	if (unlikely(newdp->dccps_hc_rx_ccid == NULL \|\|
	143	newdp->dccps_hc_tx_ccid == NULL)) {
ae31c339	144	dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
91f0ebf7 ACM	145	ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
91f0ebf7 ACM	146	ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
7c657876 ACM	147	out_free:
	148	/* It is still raw copy of parent, so invalidate
	149	* destructor and make plain sk_free() */
	150	newsk->sk_destruct = NULL;
	151	sk_free(newsk);
	152	return NULL;
	153	}
	154
7c657876 ACM	155	/*
	156	* Step 3: Process LISTEN state
	157	*
d83ca5ac GR	158	* Choose S.ISS (initial seqno) or set from Init Cookies
	159	* Initialize S.GAR := S.ISS
	160	* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
7c657876 ACM	161	*/
	162
	163	/* See dccp_v4_conn_request */
a4bf3902	164	newdmsk->dccpms_sequence_window = req->rcv_wnd;
7c657876 ACM	165
	166	newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
	167	dccp_update_gsr(newsk, dreq->dreq_isr);
	168
	169	newdp->dccps_iss = dreq->dreq_iss;
	170	dccp_update_gss(newsk, dreq->dreq_iss);
	171
03ace394 ACM	172	/*
	173	* SWL and AWL are initially adjusted so that they are not less than
	174	* the initial Sequence Numbers received and sent, respectively:
	175	* SWL := max(GSR + 1 - floor(W/4), ISR),
	176	* AWL := max(GSS - W' + 1, ISS).
	177	* These adjustments MUST be applied only at the beginning of the
	178	* connection.
	179	*/
	180	dccp_set_seqno(&newdp->dccps_swl,
	181	max48(newdp->dccps_swl, newdp->dccps_isr));
	182	dccp_set_seqno(&newdp->dccps_awl,
	183	max48(newdp->dccps_awl, newdp->dccps_iss));
	184
7c657876 ACM	185	dccp_init_xmit_timers(newsk);
	186
	187	DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
	188	}
	189	return newsk;
	190	}
	191
f21e68ca ACM	192	EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
f21e68ca ACM	193
8109b02b	194	/*
7c657876 ACM	195	* Process an incoming packet for RESPOND sockets represented
	196	* as an request_sock.
	197	*/
	198	struct sock dccp_check_req(struct sock sk, struct sk_buff *skb,
	199	struct request_sock *req,
	200	struct request_sock **prev)
	201	{
	202	struct sock *child = NULL;
	203
	204	/* Check for retransmitted REQUEST */
	205	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
e11d9d30	206	struct dccp_request_sock *dreq = dccp_rsk(req);
7c657876	207
e11d9d30	208	if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
7c657876	209	dccp_pr_debug("Retransmitted REQUEST\n");
e11d9d30 GR	210	dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
	211	/*
	212	* Send another RESPONSE packet
	213	* To protect against Request floods, increment retrans
	214	* counter (backoff, monitored by dccp_response_timer).
	215	*/
	216	req->retrans++;
7c657876 ACM	217	req->rsk_ops->rtx_syn_ack(sk, req, NULL);
	218	}
	219	/* Network Duplicate, discard packet */
	220	return NULL;
	221	}
	222
	223	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	224
	225	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
	226	dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
	227	goto drop;
	228
	229	/* Invalid ACK */
	230	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
7690af3f ACM	231	dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
7690af3f ACM	232	"dreq_iss=%llu\n",
f6ccf554 DM	233	(unsigned long long)
	234	DCCP_SKB_CB(skb)->dccpd_ack_seq,
	235	(unsigned long long)
	236	dccp_rsk(req)->dreq_iss);
7c657876 ACM	237	goto drop;
	238	}
	239
57cca05a	240	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
7c657876 ACM	241	if (child == NULL)
	242	goto listen_overflow;
	243
	244	/* FIXME: deal with options */
	245
	246	inet_csk_reqsk_queue_unlink(sk, req, prev);
	247	inet_csk_reqsk_queue_removed(sk, req);
	248	inet_csk_reqsk_queue_add(sk, req, child);
	249	out:
	250	return child;
	251	listen_overflow:
	252	dccp_pr_debug("listen_overflow!\n");
	253	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
	254	drop:
	255	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
cfb6eeb4	256	req->rsk_ops->send_reset(sk, skb);
7c657876 ACM	257
	258	inet_csk_reqsk_queue_drop(sk, req, prev);
	259	goto out;
	260	}
	261
f21e68ca ACM	262	EXPORT_SYMBOL_GPL(dccp_check_req);
f21e68ca ACM	263
7c657876 ACM	264	/*
	265	* Queue segment on the new socket if the new socket is active,
	266	* otherwise we just shortcircuit this and continue with
	267	* the new socket.
	268	*/
	269	int dccp_child_process(struct sock parent, struct sock child,
	270	struct sk_buff *skb)
	271	{
	272	int ret = 0;
	273	const int state = child->sk_state;
	274
	275	if (!sock_owned_by_user(child)) {
7690af3f ACM	276	ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
7690af3f ACM	277	skb->len);
7c657876 ACM	278
	279	/* Wakeup parent, send SIGIO */
	280	if (state == DCCP_RESPOND && child->sk_state != state)
	281	parent->sk_data_ready(parent, 0);
	282	} else {
	283	/* Alas, it is possible again, because we do lookup
	284	* in main socket hash table and lock on listening
	285	* socket does not protect us more.
	286	*/
	287	sk_add_backlog(child, skb);
	288	}
	289
	290	bh_unlock_sock(child);
	291	sock_put(child);
	292	return ret;
	293	}
f21e68ca ACM	294
f21e68ca ACM	295	EXPORT_SYMBOL_GPL(dccp_child_process);
8a73cd09 GR	296
	297	void dccp_reqsk_send_ack(struct sk_buff skb, struct request_sock rsk)
	298	{
59348b19	299	DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
8a73cd09 GR	300	}
	301
	302	EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
cf557926 GR	303
	304	void dccp_reqsk_init(struct request_sock req, struct sk_buff skb)
	305	{
	306	inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
	307	inet_rsk(req)->acked = 0;
afb0a34d	308	req->rcv_wnd = sysctl_dccp_feat_sequence_window;
cf557926 GR	309	}
	310
	311	EXPORT_SYMBOL_GPL(dccp_reqsk_init);