minisocks.c revision 8a73cd09d96aa01743316657fc4e6864fe79b703 
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
13#include <linux/dccp.h>
14#include <linux/kernel.h>
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
22#include "ackvec.h"
23#include "ccid.h"
24#include "dccp.h"
25#include "feat.h"
26
27struct inet_timewait_death_row dccp_death_row = {
28	.sysctl_max_tw_buckets = NR_FILE * 2,
29	.period		= DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
30	.death_lock	= SPIN_LOCK_UNLOCKED,
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,
35					     inet_twdr_twkill_work,
36					     &dccp_death_row),
37/* Short-time timewait calendar */
38
39	.twcal_hand	= -1,
40	.twcal_timer	= TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
41					    (unsigned long)&dccp_death_row),
42};
43
44EXPORT_SYMBOL_GPL(dccp_death_row);
45
46void dccp_time_wait(struct sock *sk, int state, int timeo)
47{
48	struct inet_timewait_sock *tw = NULL;
49
50	if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
51		tw = inet_twsk_alloc(sk, state);
52
53	if (tw != NULL) {
54		const struct inet_connection_sock *icsk = inet_csk(sk);
55		const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
56#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
57		if (tw->tw_family == PF_INET6) {
58			const struct ipv6_pinfo *np = inet6_sk(sk);
59			struct inet6_timewait_sock *tw6;
60
61			tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
62			tw6 = inet6_twsk((struct sock *)tw);
63			ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
64			ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
65			tw->tw_ipv6only = np->ipv6only;
66		}
67#endif
68		/* Linkage updates. */
69		__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
70
71		/* Get the TIME_WAIT timeout firing. */
72		if (timeo < rto)
73			timeo = rto;
74
75		tw->tw_timeout = DCCP_TIMEWAIT_LEN;
76		if (state == DCCP_TIME_WAIT)
77			timeo = DCCP_TIMEWAIT_LEN;
78
79		inet_twsk_schedule(tw, &dccp_death_row, timeo,
80				   DCCP_TIMEWAIT_LEN);
81		inet_twsk_put(tw);
82	} else {
83		/* Sorry, if we're out of memory, just CLOSE this
84		 * socket up.  We've got bigger problems than
85		 * non-graceful socket closings.
86		 */
87		LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket "
88					 "table overflow\n");
89	}
90
91	dccp_done(sk);
92}
93
94struct sock *dccp_create_openreq_child(struct sock *sk,
95				       const struct request_sock *req,
96				       const struct sk_buff *skb)
97{
98	/*
99	 * Step 3: Process LISTEN state
100	 *
101	 * // Generate a new socket and switch to that socket
102	 * Set S := new socket for this port pair
103	 */
104	struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
105
106	if (newsk != NULL) {
107		const struct dccp_request_sock *dreq = dccp_rsk(req);
108		struct inet_connection_sock *newicsk = inet_csk(sk);
109		struct dccp_sock *newdp = dccp_sk(newsk);
110		struct dccp_minisock *newdmsk = dccp_msk(newsk);
111
112		newdp->dccps_role	   = DCCP_ROLE_SERVER;
113		newdp->dccps_hc_rx_ackvec  = NULL;
114		newdp->dccps_service_list  = NULL;
115		newdp->dccps_service	   = dreq->dreq_service;
116		newicsk->icsk_rto	   = DCCP_TIMEOUT_INIT;
117		do_gettimeofday(&newdp->dccps_epoch);
118
119		if (dccp_feat_clone(sk, newsk))
120			goto out_free;
121
122		if (newdmsk->dccpms_send_ack_vector) {
123			newdp->dccps_hc_rx_ackvec =
124						dccp_ackvec_alloc(GFP_ATOMIC);
125			if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
126				goto out_free;
127		}
128
129		newdp->dccps_hc_rx_ccid =
130			    ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
131					   newsk, GFP_ATOMIC);
132		newdp->dccps_hc_tx_ccid =
133			    ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
134					   newsk, GFP_ATOMIC);
135		if (unlikely(newdp->dccps_hc_rx_ccid == NULL ||
136			     newdp->dccps_hc_tx_ccid == NULL)) {
137			dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
138			ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
139			ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
140out_free:
141			/* It is still raw copy of parent, so invalidate
142			 * destructor and make plain sk_free() */
143			newsk->sk_destruct = NULL;
144			sk_free(newsk);
145			return NULL;
146		}
147
148		/*
149		 * Step 3: Process LISTEN state
150		 *
151		 *	Choose S.ISS (initial seqno) or set from Init Cookie
152		 *	Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
153		 *	Cookie
154		 */
155
156		/* See dccp_v4_conn_request */
157		newdmsk->dccpms_sequence_window = req->rcv_wnd;
158
159		newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
160		dccp_update_gsr(newsk, dreq->dreq_isr);
161
162		newdp->dccps_iss = dreq->dreq_iss;
163		dccp_update_gss(newsk, dreq->dreq_iss);
164
165		/*
166		 * SWL and AWL are initially adjusted so that they are not less than
167		 * the initial Sequence Numbers received and sent, respectively:
168		 *	SWL := max(GSR + 1 - floor(W/4), ISR),
169		 *	AWL := max(GSS - W' + 1, ISS).
170		 * These adjustments MUST be applied only at the beginning of the
171		 * connection.
172		 */
173		dccp_set_seqno(&newdp->dccps_swl,
174			       max48(newdp->dccps_swl, newdp->dccps_isr));
175		dccp_set_seqno(&newdp->dccps_awl,
176			       max48(newdp->dccps_awl, newdp->dccps_iss));
177
178		dccp_init_xmit_timers(newsk);
179
180		DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
181	}
182	return newsk;
183}
184
185EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
186
187/*
188 * Process an incoming packet for RESPOND sockets represented
189 * as an request_sock.
190 */
191struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
192			    struct request_sock *req,
193			    struct request_sock **prev)
194{
195	struct sock *child = NULL;
196
197	/* Check for retransmitted REQUEST */
198	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
199		if (after48(DCCP_SKB_CB(skb)->dccpd_seq,
200			    dccp_rsk(req)->dreq_isr)) {
201			struct dccp_request_sock *dreq = dccp_rsk(req);
202
203			dccp_pr_debug("Retransmitted REQUEST\n");
204			/* Send another RESPONSE packet */
205			dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1);
206			dccp_set_seqno(&dreq->dreq_isr,
207				       DCCP_SKB_CB(skb)->dccpd_seq);
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) {
222		dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
223			      "dreq_iss=%llu\n",
224			      (unsigned long long)
225			      DCCP_SKB_CB(skb)->dccpd_ack_seq,
226			      (unsigned long long)
227			      dccp_rsk(req)->dreq_iss);
228		goto drop;
229	}
230
231	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
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);
240out:
241	return child;
242listen_overflow:
243	dccp_pr_debug("listen_overflow!\n");
244	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
245drop:
246	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
247		req->rsk_ops->send_reset(skb);
248
249	inet_csk_reqsk_queue_drop(sk, req, prev);
250	goto out;
251}
252
253EXPORT_SYMBOL_GPL(dccp_check_req);
254
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 */
260int 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)) {
267		ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
268					     skb->len);
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}
285
286EXPORT_SYMBOL_GPL(dccp_child_process);
287
288void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk)
289{
290	pr_info(KERN_WARNING "DCCP: ACK packets are never sent in "
291			     "LISTEN/RESPOND state\n");
292	dump_stack();
293}
294
295EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
296