[linux-block.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;
		newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
		newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
		newicsk->icsk_rto	    = DCCP_TIMEOUT_INIT;

		INIT_LIST_HEAD(&newdp->dccps_featneg);
		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_iss = dreq->dreq_iss;
		dccp_update_gss(newsk, dreq->dreq_iss);

		newdp->dccps_isr = dreq->dreq_isr;
		dccp_update_gsr(newsk, dreq->dreq_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.
		 */
		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;
	struct dccp_request_sock *dreq = dccp_rsk(req);

	/* Check for retransmitted REQUEST */
	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {

		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);
		}
		/* 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 != dreq->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) dreq->dreq_iss);
		goto drop;
	}

	if (dccp_parse_options(sk, dreq, skb))
		 goto drop;

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

	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 sock *sk, 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);

int dccp_reqsk_init(struct request_sock *req,
		    struct dccp_sock const *dp, struct sk_buff const *skb)
{
	struct dccp_request_sock *dreq = dccp_rsk(req);

	inet_rsk(req)->rmt_port	  = dccp_hdr(skb)->dccph_sport;
	inet_rsk(req)->loc_port	  = dccp_hdr(skb)->dccph_dport;
	inet_rsk(req)->acked	  = 0;
	req->rcv_wnd		  = sysctl_dccp_feat_sequence_window;
	dreq->dreq_timestamp_echo = 0;

	/* inherit feature negotiation options from listening socket */
	return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
}

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
b4d4f7c7 GR	120	newdp->dccps_role = DCCP_ROLE_SERVER;
	121	newdp->dccps_hc_rx_ackvec = NULL;
	122	newdp->dccps_service_list = NULL;
	123	newdp->dccps_service = dreq->dreq_service;
	124	newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
	125	newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
	126	newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
7c657876	127
ac75773c	128	INIT_LIST_HEAD(&newdp->dccps_featneg);
afe00251 AB	129	if (dccp_feat_clone(sk, newsk))
	130	goto out_free;
	131
a4bf3902	132	if (newdmsk->dccpms_send_ack_vector) {
ae31c339	133	newdp->dccps_hc_rx_ackvec =
7400d781	134	dccp_ackvec_alloc(GFP_ATOMIC);
ae31c339	135	if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
7c657876 ACM	136	goto out_free;
	137	}
	138
91f0ebf7	139	newdp->dccps_hc_rx_ccid =
a4bf3902	140	ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
91f0ebf7 ACM	141	newsk, GFP_ATOMIC);
91f0ebf7 ACM	142	newdp->dccps_hc_tx_ccid =
a4bf3902	143	ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
91f0ebf7 ACM	144	newsk, GFP_ATOMIC);
	145	if (unlikely(newdp->dccps_hc_rx_ccid == NULL \|\|
	146	newdp->dccps_hc_tx_ccid == NULL)) {
ae31c339	147	dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
91f0ebf7 ACM	148	ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
91f0ebf7 ACM	149	ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
7c657876 ACM	150	out_free:
	151	/* It is still raw copy of parent, so invalidate
	152	* destructor and make plain sk_free() */
	153	newsk->sk_destruct = NULL;
	154	sk_free(newsk);
	155	return NULL;
	156	}
	157
7c657876 ACM	158	/*
	159	* Step 3: Process LISTEN state
	160	*
d83ca5ac GR	161	* Choose S.ISS (initial seqno) or set from Init Cookies
	162	* Initialize S.GAR := S.ISS
	163	* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
7c657876 ACM	164	*/
	165
	166	/* See dccp_v4_conn_request */
a4bf3902	167	newdmsk->dccpms_sequence_window = req->rcv_wnd;
7c657876	168
be4c798a	169	newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
7c657876 ACM	170	dccp_update_gss(newsk, dreq->dreq_iss);
7c657876 ACM	171
be4c798a GR	172	newdp->dccps_isr = dreq->dreq_isr;
	173	dccp_update_gsr(newsk, dreq->dreq_isr);
	174
03ace394 ACM	175	/*
	176	* SWL and AWL are initially adjusted so that they are not less than
	177	* the initial Sequence Numbers received and sent, respectively:
	178	* SWL := max(GSR + 1 - floor(W/4), ISR),
	179	* AWL := max(GSS - W' + 1, ISS).
	180	* These adjustments MUST be applied only at the beginning of the
	181	* connection.
	182	*/
	183	dccp_set_seqno(&newdp->dccps_swl,
	184	max48(newdp->dccps_swl, newdp->dccps_isr));
	185	dccp_set_seqno(&newdp->dccps_awl,
	186	max48(newdp->dccps_awl, newdp->dccps_iss));
	187
7c657876 ACM	188	dccp_init_xmit_timers(newsk);
	189
	190	DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
	191	}
	192	return newsk;
	193	}
	194
f21e68ca ACM	195	EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
f21e68ca ACM	196
8109b02b	197	/*
7c657876 ACM	198	* Process an incoming packet for RESPOND sockets represented
	199	* as an request_sock.
	200	*/
	201	struct sock dccp_check_req(struct sock sk, struct sk_buff *skb,
	202	struct request_sock *req,
	203	struct request_sock **prev)
	204	{
	205	struct sock *child = NULL;
8109616e	206	struct dccp_request_sock *dreq = dccp_rsk(req);
7c657876 ACM	207
	208	/* Check for retransmitted REQUEST */
	209	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
7c657876	210
e11d9d30	211	if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
7c657876	212	dccp_pr_debug("Retransmitted REQUEST\n");
e11d9d30 GR	213	dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
	214	/*
	215	* Send another RESPONSE packet
	216	* To protect against Request floods, increment retrans
	217	* counter (backoff, monitored by dccp_response_timer).
	218	*/
	219	req->retrans++;
fd80eb94	220	req->rsk_ops->rtx_syn_ack(sk, req);
7c657876 ACM	221	}
	222	/* Network Duplicate, discard packet */
	223	return NULL;
	224	}
	225
	226	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
	227
	228	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
	229	dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
	230	goto drop;
	231
	232	/* Invalid ACK */
8109616e	233	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
7690af3f ACM	234	dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
7690af3f ACM	235	"dreq_iss=%llu\n",
f6ccf554 DM	236	(unsigned long long)
f6ccf554 DM	237	DCCP_SKB_CB(skb)->dccpd_ack_seq,
8109616e	238	(unsigned long long) dreq->dreq_iss);
7c657876 ACM	239	goto drop;
	240	}
	241
8109616e GR	242	if (dccp_parse_options(sk, dreq, skb))
	243	goto drop;
	244
57cca05a	245	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
7c657876 ACM	246	if (child == NULL)
	247	goto listen_overflow;
	248
7c657876 ACM	249	inet_csk_reqsk_queue_unlink(sk, req, prev);
	250	inet_csk_reqsk_queue_removed(sk, req);
	251	inet_csk_reqsk_queue_add(sk, req, child);
	252	out:
	253	return child;
	254	listen_overflow:
	255	dccp_pr_debug("listen_overflow!\n");
	256	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
	257	drop:
	258	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
cfb6eeb4	259	req->rsk_ops->send_reset(sk, skb);
7c657876 ACM	260
	261	inet_csk_reqsk_queue_drop(sk, req, prev);
	262	goto out;
	263	}
	264
f21e68ca ACM	265	EXPORT_SYMBOL_GPL(dccp_check_req);
f21e68ca ACM	266
7c657876 ACM	267	/*
	268	* Queue segment on the new socket if the new socket is active,
	269	* otherwise we just shortcircuit this and continue with
	270	* the new socket.
	271	*/
	272	int dccp_child_process(struct sock parent, struct sock child,
	273	struct sk_buff *skb)
	274	{
	275	int ret = 0;
	276	const int state = child->sk_state;
	277
	278	if (!sock_owned_by_user(child)) {
7690af3f ACM	279	ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
7690af3f ACM	280	skb->len);
7c657876 ACM	281
	282	/* Wakeup parent, send SIGIO */
	283	if (state == DCCP_RESPOND && child->sk_state != state)
	284	parent->sk_data_ready(parent, 0);
	285	} else {
	286	/* Alas, it is possible again, because we do lookup
	287	* in main socket hash table and lock on listening
	288	* socket does not protect us more.
	289	*/
	290	sk_add_backlog(child, skb);
	291	}
	292
	293	bh_unlock_sock(child);
	294	sock_put(child);
	295	return ret;
	296	}
f21e68ca ACM	297
f21e68ca ACM	298	EXPORT_SYMBOL_GPL(dccp_child_process);
8a73cd09	299
6edafaaf GJ	300	void dccp_reqsk_send_ack(struct sock sk, struct sk_buff skb,
6edafaaf GJ	301	struct request_sock *rsk)
8a73cd09	302	{
59348b19	303	DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
8a73cd09 GR	304	}
	305
	306	EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
cf557926	307
ac75773c GR	308	int dccp_reqsk_init(struct request_sock *req,
ac75773c GR	309	struct dccp_sock const dp, struct sk_buff const skb)
cf557926	310	{
b4d4f7c7 GR	311	struct dccp_request_sock *dreq = dccp_rsk(req);
	312
	313	inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
944f7502	314	inet_rsk(req)->loc_port = dccp_hdr(skb)->dccph_dport;
b4d4f7c7 GR	315	inet_rsk(req)->acked = 0;
	316	req->rcv_wnd = sysctl_dccp_feat_sequence_window;
	317	dreq->dreq_timestamp_echo = 0;
ac75773c GR	318
	319	/* inherit feature negotiation options from listening socket */
	320	return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
cf557926 GR	321	}
	322
	323	EXPORT_SYMBOL_GPL(dccp_reqsk_init);