ccid: ccid-2/3 code cosmetics
[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/gfp.h>
15 #include <linux/kernel.h>
16 #include <linux/skbuff.h>
17 #include <linux/timer.h>
18
19 #include <net/sock.h>
20 #include <net/xfrm.h>
21 #include <net/inet_timewait_sock.h>
22
23 #include "ackvec.h"
24 #include "ccid.h"
25 #include "dccp.h"
26 #include "feat.h"
27
28 struct inet_timewait_death_row dccp_death_row = {
29         .sysctl_max_tw_buckets = NR_FILE * 2,
30         .period         = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
31         .death_lock     = __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock),
32         .hashinfo       = &dccp_hashinfo,
33         .tw_timer       = TIMER_INITIALIZER(inet_twdr_hangman, 0,
34                                             (unsigned long)&dccp_death_row),
35         .twkill_work    = __WORK_INITIALIZER(dccp_death_row.twkill_work,
36                                              inet_twdr_twkill_work),
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
44 EXPORT_SYMBOL_GPL(dccp_death_row);
45
46 void 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                 DCCP_WARN("time wait bucket table overflow\n");
88         }
89
90         dccp_done(sk);
91 }
92
93 struct sock *dccp_create_openreq_child(struct sock *sk,
94                                        const struct request_sock *req,
95                                        const struct sk_buff *skb)
96 {
97         /*
98          * Step 3: Process LISTEN state
99          *
100          *   (* Generate a new socket and switch to that socket *)
101          *   Set S := new socket for this port pair
102          */
103         struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
104
105         if (newsk != NULL) {
106                 struct dccp_request_sock *dreq = dccp_rsk(req);
107                 struct inet_connection_sock *newicsk = inet_csk(newsk);
108                 struct dccp_sock *newdp = dccp_sk(newsk);
109
110                 newdp->dccps_role           = DCCP_ROLE_SERVER;
111                 newdp->dccps_hc_rx_ackvec   = NULL;
112                 newdp->dccps_service_list   = NULL;
113                 newdp->dccps_service        = dreq->dreq_service;
114                 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
115                 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
116                 newicsk->icsk_rto           = DCCP_TIMEOUT_INIT;
117
118                 INIT_LIST_HEAD(&newdp->dccps_featneg);
119                 /*
120                  * Step 3: Process LISTEN state
121                  *
122                  *    Choose S.ISS (initial seqno) or set from Init Cookies
123                  *    Initialize S.GAR := S.ISS
124                  *    Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
125                  */
126                 newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
127                 dccp_update_gss(newsk, dreq->dreq_iss);
128
129                 newdp->dccps_isr = dreq->dreq_isr;
130                 dccp_update_gsr(newsk, dreq->dreq_isr);
131
132                 /*
133                  * SWL and AWL are initially adjusted so that they are not less than
134                  * the initial Sequence Numbers received and sent, respectively:
135                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
136                  *      AWL := max(GSS - W' + 1, ISS).
137                  * These adjustments MUST be applied only at the beginning of the
138                  * connection.
139                  */
140                 dccp_set_seqno(&newdp->dccps_swl,
141                                max48(newdp->dccps_swl, newdp->dccps_isr));
142                 dccp_set_seqno(&newdp->dccps_awl,
143                                max48(newdp->dccps_awl, newdp->dccps_iss));
144
145                 /*
146                  * Activate features after initialising the sequence numbers,
147                  * since CCID initialisation may depend on GSS, ISR, ISS etc.
148                  */
149                 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
150                         /* It is still raw copy of parent, so invalidate
151                          * destructor and make plain sk_free() */
152                         newsk->sk_destruct = NULL;
153                         sk_free(newsk);
154                         return NULL;
155                 }
156                 dccp_init_xmit_timers(newsk);
157
158                 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
159         }
160         return newsk;
161 }
162
163 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
164
165 /*
166  * Process an incoming packet for RESPOND sockets represented
167  * as an request_sock.
168  */
169 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
170                             struct request_sock *req,
171                             struct request_sock **prev)
172 {
173         struct sock *child = NULL;
174         struct dccp_request_sock *dreq = dccp_rsk(req);
175
176         /* Check for retransmitted REQUEST */
177         if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
178
179                 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
180                         dccp_pr_debug("Retransmitted REQUEST\n");
181                         dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
182                         /*
183                          * Send another RESPONSE packet
184                          * To protect against Request floods, increment retrans
185                          * counter (backoff, monitored by dccp_response_timer).
186                          */
187                         req->retrans++;
188                         req->rsk_ops->rtx_syn_ack(sk, req, NULL);
189                 }
190                 /* Network Duplicate, discard packet */
191                 return NULL;
192         }
193
194         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
195
196         if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
197             dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
198                 goto drop;
199
200         /* Invalid ACK */
201         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
202                 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
203                               "dreq_iss=%llu\n",
204                               (unsigned long long)
205                               DCCP_SKB_CB(skb)->dccpd_ack_seq,
206                               (unsigned long long) dreq->dreq_iss);
207                 goto drop;
208         }
209
210         if (dccp_parse_options(sk, dreq, skb))
211                  goto drop;
212
213         child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
214         if (child == NULL)
215                 goto listen_overflow;
216
217         inet_csk_reqsk_queue_unlink(sk, req, prev);
218         inet_csk_reqsk_queue_removed(sk, req);
219         inet_csk_reqsk_queue_add(sk, req, child);
220 out:
221         return child;
222 listen_overflow:
223         dccp_pr_debug("listen_overflow!\n");
224         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
225 drop:
226         if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
227                 req->rsk_ops->send_reset(sk, skb);
228
229         inet_csk_reqsk_queue_drop(sk, req, prev);
230         goto out;
231 }
232
233 EXPORT_SYMBOL_GPL(dccp_check_req);
234
235 /*
236  *  Queue segment on the new socket if the new socket is active,
237  *  otherwise we just shortcircuit this and continue with
238  *  the new socket.
239  */
240 int dccp_child_process(struct sock *parent, struct sock *child,
241                        struct sk_buff *skb)
242 {
243         int ret = 0;
244         const int state = child->sk_state;
245
246         if (!sock_owned_by_user(child)) {
247                 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
248                                              skb->len);
249
250                 /* Wakeup parent, send SIGIO */
251                 if (state == DCCP_RESPOND && child->sk_state != state)
252                         parent->sk_data_ready(parent, 0);
253         } else {
254                 /* Alas, it is possible again, because we do lookup
255                  * in main socket hash table and lock on listening
256                  * socket does not protect us more.
257                  */
258                 __sk_add_backlog(child, skb);
259         }
260
261         bh_unlock_sock(child);
262         sock_put(child);
263         return ret;
264 }
265
266 EXPORT_SYMBOL_GPL(dccp_child_process);
267
268 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
269                          struct request_sock *rsk)
270 {
271         DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
272 }
273
274 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
275
276 int dccp_reqsk_init(struct request_sock *req,
277                     struct dccp_sock const *dp, struct sk_buff const *skb)
278 {
279         struct dccp_request_sock *dreq = dccp_rsk(req);
280
281         inet_rsk(req)->rmt_port   = dccp_hdr(skb)->dccph_sport;
282         inet_rsk(req)->loc_port   = dccp_hdr(skb)->dccph_dport;
283         inet_rsk(req)->acked      = 0;
284         dreq->dreq_timestamp_echo = 0;
285
286         /* inherit feature negotiation options from listening socket */
287         return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
288 }
289
290 EXPORT_SYMBOL_GPL(dccp_reqsk_init);