dccp: Remove obsolete parts of the old CCID interface
[linux-2.6.git] / net / dccp / minisocks.c
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
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,
30         .death_lock     = __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock),
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 /* 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
43 EXPORT_SYMBOL_GPL(dccp_death_row);
44
45 void dccp_minisock_init(struct dccp_minisock *dmsk)
46 {
47         dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
48         dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
49         dmsk->dccpms_send_ndp_count  = sysctl_dccp_feat_send_ndp_count;
50 }
51
52 void dccp_time_wait(struct sock *sk, int state, int timeo)
53 {
54         struct inet_timewait_sock *tw = NULL;
55
56         if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
57                 tw = inet_twsk_alloc(sk, state);
58
59         if (tw != NULL) {
60                 const struct inet_connection_sock *icsk = inet_csk(sk);
61                 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
62 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
63                 if (tw->tw_family == PF_INET6) {
64                         const struct ipv6_pinfo *np = inet6_sk(sk);
65                         struct inet6_timewait_sock *tw6;
66
67                         tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
68                         tw6 = inet6_twsk((struct sock *)tw);
69                         ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
70                         ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
71                         tw->tw_ipv6only = np->ipv6only;
72                 }
73 #endif
74                 /* Linkage updates. */
75                 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
76
77                 /* Get the TIME_WAIT timeout firing. */
78                 if (timeo < rto)
79                         timeo = rto;
80
81                 tw->tw_timeout = DCCP_TIMEWAIT_LEN;
82                 if (state == DCCP_TIME_WAIT)
83                         timeo = DCCP_TIMEWAIT_LEN;
84
85                 inet_twsk_schedule(tw, &dccp_death_row, timeo,
86                                    DCCP_TIMEWAIT_LEN);
87                 inet_twsk_put(tw);
88         } else {
89                 /* Sorry, if we're out of memory, just CLOSE this
90                  * socket up.  We've got bigger problems than
91                  * non-graceful socket closings.
92                  */
93                 DCCP_WARN("time wait bucket table overflow\n");
94         }
95
96         dccp_done(sk);
97 }
98
99 struct sock *dccp_create_openreq_child(struct sock *sk,
100                                        const struct request_sock *req,
101                                        const struct sk_buff *skb)
102 {
103         /*
104          * Step 3: Process LISTEN state
105          *
106          *   (* Generate a new socket and switch to that socket *)
107          *   Set S := new socket for this port pair
108          */
109         struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
110
111         if (newsk != NULL) {
112                 struct dccp_request_sock *dreq = dccp_rsk(req);
113                 struct inet_connection_sock *newicsk = inet_csk(newsk);
114                 struct dccp_sock *newdp = dccp_sk(newsk);
115                 struct dccp_minisock *newdmsk = dccp_msk(newsk);
116
117                 newdp->dccps_role           = DCCP_ROLE_SERVER;
118                 newdp->dccps_hc_rx_ackvec   = NULL;
119                 newdp->dccps_service_list   = NULL;
120                 newdp->dccps_service        = dreq->dreq_service;
121                 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
122                 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
123                 newicsk->icsk_rto           = DCCP_TIMEOUT_INIT;
124
125                 INIT_LIST_HEAD(&newdp->dccps_featneg);
126                 /*
127                  * Step 3: Process LISTEN state
128                  *
129                  *    Choose S.ISS (initial seqno) or set from Init Cookies
130                  *    Initialize S.GAR := S.ISS
131                  *    Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
132                  */
133
134                 /* See dccp_v4_conn_request */
135                 newdmsk->dccpms_sequence_window = req->rcv_wnd;
136
137                 newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
138                 dccp_update_gss(newsk, dreq->dreq_iss);
139
140                 newdp->dccps_isr = dreq->dreq_isr;
141                 dccp_update_gsr(newsk, dreq->dreq_isr);
142
143                 /*
144                  * SWL and AWL are initially adjusted so that they are not less than
145                  * the initial Sequence Numbers received and sent, respectively:
146                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
147                  *      AWL := max(GSS - W' + 1, ISS).
148                  * These adjustments MUST be applied only at the beginning of the
149                  * connection.
150                  */
151                 dccp_set_seqno(&newdp->dccps_swl,
152                                max48(newdp->dccps_swl, newdp->dccps_isr));
153                 dccp_set_seqno(&newdp->dccps_awl,
154                                max48(newdp->dccps_awl, newdp->dccps_iss));
155
156                 /*
157                  * Activate features after initialising the sequence numbers,
158                  * since CCID initialisation may depend on GSS, ISR, ISS etc.
159                  */
160                 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
161                         /* It is still raw copy of parent, so invalidate
162                          * destructor and make plain sk_free() */
163                         newsk->sk_destruct = NULL;
164                         sk_free(newsk);
165                         return NULL;
166                 }
167                 dccp_init_xmit_timers(newsk);
168
169                 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
170         }
171         return newsk;
172 }
173
174 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
175
176 /*
177  * Process an incoming packet for RESPOND sockets represented
178  * as an request_sock.
179  */
180 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
181                             struct request_sock *req,
182                             struct request_sock **prev)
183 {
184         struct sock *child = NULL;
185         struct dccp_request_sock *dreq = dccp_rsk(req);
186
187         /* Check for retransmitted REQUEST */
188         if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
189
190                 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
191                         dccp_pr_debug("Retransmitted REQUEST\n");
192                         dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
193                         /*
194                          * Send another RESPONSE packet
195                          * To protect against Request floods, increment retrans
196                          * counter (backoff, monitored by dccp_response_timer).
197                          */
198                         req->retrans++;
199                         req->rsk_ops->rtx_syn_ack(sk, req);
200                 }
201                 /* Network Duplicate, discard packet */
202                 return NULL;
203         }
204
205         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
206
207         if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
208             dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
209                 goto drop;
210
211         /* Invalid ACK */
212         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
213                 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
214                               "dreq_iss=%llu\n",
215                               (unsigned long long)
216                               DCCP_SKB_CB(skb)->dccpd_ack_seq,
217                               (unsigned long long) dreq->dreq_iss);
218                 goto drop;
219         }
220
221         if (dccp_parse_options(sk, dreq, skb))
222                  goto drop;
223
224         child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
225         if (child == NULL)
226                 goto listen_overflow;
227
228         inet_csk_reqsk_queue_unlink(sk, req, prev);
229         inet_csk_reqsk_queue_removed(sk, req);
230         inet_csk_reqsk_queue_add(sk, req, child);
231 out:
232         return child;
233 listen_overflow:
234         dccp_pr_debug("listen_overflow!\n");
235         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
236 drop:
237         if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
238                 req->rsk_ops->send_reset(sk, skb);
239
240         inet_csk_reqsk_queue_drop(sk, req, prev);
241         goto out;
242 }
243
244 EXPORT_SYMBOL_GPL(dccp_check_req);
245
246 /*
247  *  Queue segment on the new socket if the new socket is active,
248  *  otherwise we just shortcircuit this and continue with
249  *  the new socket.
250  */
251 int dccp_child_process(struct sock *parent, struct sock *child,
252                        struct sk_buff *skb)
253 {
254         int ret = 0;
255         const int state = child->sk_state;
256
257         if (!sock_owned_by_user(child)) {
258                 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
259                                              skb->len);
260
261                 /* Wakeup parent, send SIGIO */
262                 if (state == DCCP_RESPOND && child->sk_state != state)
263                         parent->sk_data_ready(parent, 0);
264         } else {
265                 /* Alas, it is possible again, because we do lookup
266                  * in main socket hash table and lock on listening
267                  * socket does not protect us more.
268                  */
269                 sk_add_backlog(child, skb);
270         }
271
272         bh_unlock_sock(child);
273         sock_put(child);
274         return ret;
275 }
276
277 EXPORT_SYMBOL_GPL(dccp_child_process);
278
279 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
280                          struct request_sock *rsk)
281 {
282         DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
283 }
284
285 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
286
287 int dccp_reqsk_init(struct request_sock *req,
288                     struct dccp_sock const *dp, struct sk_buff const *skb)
289 {
290         struct dccp_request_sock *dreq = dccp_rsk(req);
291
292         inet_rsk(req)->rmt_port   = dccp_hdr(skb)->dccph_sport;
293         inet_rsk(req)->loc_port   = dccp_hdr(skb)->dccph_dport;
294         inet_rsk(req)->acked      = 0;
295         req->rcv_wnd              = sysctl_dccp_feat_sequence_window;
296         dreq->dreq_timestamp_echo = 0;
297
298         /* inherit feature negotiation options from listening socket */
299         return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
300 }
301
302 EXPORT_SYMBOL_GPL(dccp_reqsk_init);