4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
13 #include <linux/config.h>
14 #include <linux/dccp.h>
15 #include <linux/skbuff.h>
16 #include <linux/timer.h>
20 #include <net/inet_timewait_sock.h>
26 struct inet_timewait_death_row dccp_death_row
= {
27 .sysctl_max_tw_buckets
= NR_FILE
* 2,
28 .period
= DCCP_TIMEWAIT_LEN
/ INET_TWDR_TWKILL_SLOTS
,
29 .death_lock
= SPIN_LOCK_UNLOCKED
,
30 .hashinfo
= &dccp_hashinfo
,
31 .tw_timer
= TIMER_INITIALIZER(inet_twdr_hangman
, 0,
32 (unsigned long)&dccp_death_row
),
33 .twkill_work
= __WORK_INITIALIZER(dccp_death_row
.twkill_work
,
34 inet_twdr_twkill_work
,
36 /* Short-time timewait calendar */
39 .twcal_timer
= TIMER_INITIALIZER(inet_twdr_twcal_tick
, 0,
40 (unsigned long)&dccp_death_row
),
43 void dccp_time_wait(struct sock
*sk
, int state
, int timeo
)
45 struct inet_timewait_sock
*tw
= NULL
;
47 if (dccp_death_row
.tw_count
< dccp_death_row
.sysctl_max_tw_buckets
)
48 tw
= inet_twsk_alloc(sk
, state
);
51 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
52 const int rto
= (icsk
->icsk_rto
<< 2) - (icsk
->icsk_rto
>> 1);
54 /* Linkage updates. */
55 __inet_twsk_hashdance(tw
, sk
, &dccp_hashinfo
);
57 /* Get the TIME_WAIT timeout firing. */
61 tw
->tw_timeout
= DCCP_TIMEWAIT_LEN
;
62 if (state
== DCCP_TIME_WAIT
)
63 timeo
= DCCP_TIMEWAIT_LEN
;
65 inet_twsk_schedule(tw
, &dccp_death_row
, timeo
,
69 /* Sorry, if we're out of memory, just CLOSE this
70 * socket up. We've got bigger problems than
71 * non-graceful socket closings.
73 LIMIT_NETDEBUG(KERN_INFO
"DCCP: time wait bucket "
80 struct sock
*dccp_create_openreq_child(struct sock
*sk
,
81 const struct request_sock
*req
,
82 const struct sk_buff
*skb
)
85 * Step 3: Process LISTEN state
87 * // Generate a new socket and switch to that socket
88 * Set S := new socket for this port pair
90 struct sock
*newsk
= inet_csk_clone(sk
, req
, GFP_ATOMIC
);
93 const struct dccp_request_sock
*dreq
= dccp_rsk(req
);
94 struct inet_connection_sock
*newicsk
= inet_csk(sk
);
95 struct dccp_sock
*newdp
= dccp_sk(newsk
);
97 newdp
->dccps_role
= DCCP_ROLE_SERVER
;
98 newdp
->dccps_hc_rx_ackvec
= NULL
;
99 newdp
->dccps_service_list
= NULL
;
100 newdp
->dccps_service
= dreq
->dreq_service
;
101 newicsk
->icsk_rto
= DCCP_TIMEOUT_INIT
;
102 do_gettimeofday(&newdp
->dccps_epoch
);
104 if (newdp
->dccps_options
.dccpo_send_ack_vector
) {
105 newdp
->dccps_hc_rx_ackvec
=
106 dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN
,
109 * XXX: We're using the same CCIDs set on the parent,
110 * i.e. sk_clone copied the master sock and left the
111 * CCID pointers for this child, that is why we do the
114 if (unlikely(newdp
->dccps_hc_rx_ackvec
== NULL
))
118 if (unlikely(ccid_hc_rx_init(newdp
->dccps_hc_rx_ccid
,
120 ccid_hc_tx_init(newdp
->dccps_hc_tx_ccid
,
122 dccp_ackvec_free(newdp
->dccps_hc_rx_ackvec
);
123 ccid_hc_rx_exit(newdp
->dccps_hc_rx_ccid
, newsk
);
124 ccid_hc_tx_exit(newdp
->dccps_hc_tx_ccid
, newsk
);
126 /* It is still raw copy of parent, so invalidate
127 * destructor and make plain sk_free() */
128 newsk
->sk_destruct
= NULL
;
133 __ccid_get(newdp
->dccps_hc_rx_ccid
);
134 __ccid_get(newdp
->dccps_hc_tx_ccid
);
137 * Step 3: Process LISTEN state
139 * Choose S.ISS (initial seqno) or set from Init Cookie
140 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
144 /* See dccp_v4_conn_request */
145 newdp
->dccps_options
.dccpo_sequence_window
= req
->rcv_wnd
;
147 newdp
->dccps_gar
= newdp
->dccps_isr
= dreq
->dreq_isr
;
148 dccp_update_gsr(newsk
, dreq
->dreq_isr
);
150 newdp
->dccps_iss
= dreq
->dreq_iss
;
151 dccp_update_gss(newsk
, dreq
->dreq_iss
);
154 * SWL and AWL are initially adjusted so that they are not less than
155 * the initial Sequence Numbers received and sent, respectively:
156 * SWL := max(GSR + 1 - floor(W/4), ISR),
157 * AWL := max(GSS - W' + 1, ISS).
158 * These adjustments MUST be applied only at the beginning of the
161 dccp_set_seqno(&newdp
->dccps_swl
,
162 max48(newdp
->dccps_swl
, newdp
->dccps_isr
));
163 dccp_set_seqno(&newdp
->dccps_awl
,
164 max48(newdp
->dccps_awl
, newdp
->dccps_iss
));
166 dccp_init_xmit_timers(newsk
);
168 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS
);
174 * Process an incoming packet for RESPOND sockets represented
175 * as an request_sock.
177 struct sock
*dccp_check_req(struct sock
*sk
, struct sk_buff
*skb
,
178 struct request_sock
*req
,
179 struct request_sock
**prev
)
181 struct sock
*child
= NULL
;
183 /* Check for retransmitted REQUEST */
184 if (dccp_hdr(skb
)->dccph_type
== DCCP_PKT_REQUEST
) {
185 if (after48(DCCP_SKB_CB(skb
)->dccpd_seq
,
186 dccp_rsk(req
)->dreq_isr
)) {
187 struct dccp_request_sock
*dreq
= dccp_rsk(req
);
189 dccp_pr_debug("Retransmitted REQUEST\n");
190 /* Send another RESPONSE packet */
191 dccp_set_seqno(&dreq
->dreq_iss
, dreq
->dreq_iss
+ 1);
192 dccp_set_seqno(&dreq
->dreq_isr
,
193 DCCP_SKB_CB(skb
)->dccpd_seq
);
194 req
->rsk_ops
->rtx_syn_ack(sk
, req
, NULL
);
196 /* Network Duplicate, discard packet */
200 DCCP_SKB_CB(skb
)->dccpd_reset_code
= DCCP_RESET_CODE_PACKET_ERROR
;
202 if (dccp_hdr(skb
)->dccph_type
!= DCCP_PKT_ACK
&&
203 dccp_hdr(skb
)->dccph_type
!= DCCP_PKT_DATAACK
)
207 if (DCCP_SKB_CB(skb
)->dccpd_ack_seq
!= dccp_rsk(req
)->dreq_iss
) {
208 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
211 DCCP_SKB_CB(skb
)->dccpd_ack_seq
,
213 dccp_rsk(req
)->dreq_iss
);
217 child
= dccp_v4_request_recv_sock(sk
, skb
, req
, NULL
);
219 goto listen_overflow
;
221 /* FIXME: deal with options */
223 inet_csk_reqsk_queue_unlink(sk
, req
, prev
);
224 inet_csk_reqsk_queue_removed(sk
, req
);
225 inet_csk_reqsk_queue_add(sk
, req
, child
);
229 dccp_pr_debug("listen_overflow!\n");
230 DCCP_SKB_CB(skb
)->dccpd_reset_code
= DCCP_RESET_CODE_TOO_BUSY
;
232 if (dccp_hdr(skb
)->dccph_type
!= DCCP_PKT_RESET
)
233 req
->rsk_ops
->send_reset(skb
);
235 inet_csk_reqsk_queue_drop(sk
, req
, prev
);
240 * Queue segment on the new socket if the new socket is active,
241 * otherwise we just shortcircuit this and continue with
244 int dccp_child_process(struct sock
*parent
, struct sock
*child
,
248 const int state
= child
->sk_state
;
250 if (!sock_owned_by_user(child
)) {
251 ret
= dccp_rcv_state_process(child
, skb
, dccp_hdr(skb
),
254 /* Wakeup parent, send SIGIO */
255 if (state
== DCCP_RESPOND
&& child
->sk_state
!= state
)
256 parent
->sk_data_ready(parent
, 0);
258 /* Alas, it is possible again, because we do lookup
259 * in main socket hash table and lock on listening
260 * socket does not protect us more.
262 sk_add_backlog(child
, skb
);
265 bh_unlock_sock(child
);