net/dccp/minisocks.c - maze/linux - Git at Google

 /*
  *  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_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) {
 		struct dccp_request_sock *dreq = dccp_rsk(req);
 		struct inet_connection_sock *newicsk = inet_csk(newsk);
 		struct dccp_sock *newdp = dccp_sk(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);
 		/*
 		 * 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
 		 */
 		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));

 		/*
 		 * Activate features after initialising the sequence numbers,
 		 * since CCID initialisation may depend on GSS, ISR, ISS etc.
 		 */
 		if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
 			/* It is still raw copy of parent, so invalidate
 			 * destructor and make plain sk_free() */
 			newsk->sk_destruct = NULL;
 			sk_free(newsk);
 			return NULL;
 		}
 		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, 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 != 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;
 	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);
	/*
	* 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_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) {
	struct dccp_request_sock *dreq = dccp_rsk(req);
	struct inet_connection_sock *newicsk = inet_csk(newsk);
	struct dccp_sock *newdp = dccp_sk(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);
	/*
	* 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
	*/
	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));

	/*
	* Activate features after initialising the sequence numbers,
	* since CCID initialisation may depend on GSS, ISR, ISS etc.
	*/
	if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
	/* It is still raw copy of parent, so invalidate
	* destructor and make plain sk_free() */
	newsk->sk_destruct = NULL;
	sk_free(newsk);
	return NULL;
	}
	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, 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 != 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;
	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);