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Viewing changes to net/dccp/minisocks.c

  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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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 from packet (or Init Cookies)
 
125
                 *
 
126
                 *    Setting AWL/AWH and SWL/SWH happens as part of the feature
 
127
                 *    activation below, as these windows all depend on the local
 
128
                 *    and remote Sequence Window feature values (7.5.2).
 
129
                 */
 
130
                newdp->dccps_gss = newdp->dccps_iss = dreq->dreq_iss;
 
131
                newdp->dccps_gar = newdp->dccps_iss;
 
132
                newdp->dccps_gsr = newdp->dccps_isr = dreq->dreq_isr;
 
133
 
 
134
                /*
 
135
                 * Activate features: initialise CCIDs, sequence windows etc.
 
136
                 */
 
137
                if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
 
138
                        /* It is still raw copy of parent, so invalidate
 
139
                         * destructor and make plain sk_free() */
 
140
                        newsk->sk_destruct = NULL;
 
141
                        sk_free(newsk);
 
142
                        return NULL;
 
143
                }
 
144
                dccp_init_xmit_timers(newsk);
 
145
 
 
146
                DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
 
147
        }
 
148
        return newsk;
 
149
}
 
150
 
 
151
EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
 
152
 
 
153
/*
 
154
 * Process an incoming packet for RESPOND sockets represented
 
155
 * as an request_sock.
 
156
 */
 
157
struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
 
158
                            struct request_sock *req,
 
159
                            struct request_sock **prev)
 
160
{
 
161
        struct sock *child = NULL;
 
162
        struct dccp_request_sock *dreq = dccp_rsk(req);
 
163
 
 
164
        /* Check for retransmitted REQUEST */
 
165
        if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
 
166
 
 
167
                if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
 
168
                        dccp_pr_debug("Retransmitted REQUEST\n");
 
169
                        dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
 
170
                        /*
 
171
                         * Send another RESPONSE packet
 
172
                         * To protect against Request floods, increment retrans
 
173
                         * counter (backoff, monitored by dccp_response_timer).
 
174
                         */
 
175
                        req->retrans++;
 
176
                        req->rsk_ops->rtx_syn_ack(sk, req, NULL);
 
177
                }
 
178
                /* Network Duplicate, discard packet */
 
179
                return NULL;
 
180
        }
 
181
 
 
182
        DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
 
183
 
 
184
        if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
 
185
            dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
 
186
                goto drop;
 
187
 
 
188
        /* Invalid ACK */
 
189
        if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
 
190
                dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
 
191
                              "dreq_iss=%llu\n",
 
192
                              (unsigned long long)
 
193
                              DCCP_SKB_CB(skb)->dccpd_ack_seq,
 
194
                              (unsigned long long) dreq->dreq_iss);
 
195
                goto drop;
 
196
        }
 
197
 
 
198
        if (dccp_parse_options(sk, dreq, skb))
 
199
                 goto drop;
 
200
 
 
201
        child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
 
202
        if (child == NULL)
 
203
                goto listen_overflow;
 
204
 
 
205
        inet_csk_reqsk_queue_unlink(sk, req, prev);
 
206
        inet_csk_reqsk_queue_removed(sk, req);
 
207
        inet_csk_reqsk_queue_add(sk, req, child);
 
208
out:
 
209
        return child;
 
210
listen_overflow:
 
211
        dccp_pr_debug("listen_overflow!\n");
 
212
        DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
 
213
drop:
 
214
        if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
 
215
                req->rsk_ops->send_reset(sk, skb);
 
216
 
 
217
        inet_csk_reqsk_queue_drop(sk, req, prev);
 
218
        goto out;
 
219
}
 
220
 
 
221
EXPORT_SYMBOL_GPL(dccp_check_req);
 
222
 
 
223
/*
 
224
 *  Queue segment on the new socket if the new socket is active,
 
225
 *  otherwise we just shortcircuit this and continue with
 
226
 *  the new socket.
 
227
 */
 
228
int dccp_child_process(struct sock *parent, struct sock *child,
 
229
                       struct sk_buff *skb)
 
230
{
 
231
        int ret = 0;
 
232
        const int state = child->sk_state;
 
233
 
 
234
        if (!sock_owned_by_user(child)) {
 
235
                ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
 
236
                                             skb->len);
 
237
 
 
238
                /* Wakeup parent, send SIGIO */
 
239
                if (state == DCCP_RESPOND && child->sk_state != state)
 
240
                        parent->sk_data_ready(parent, 0);
 
241
        } else {
 
242
                /* Alas, it is possible again, because we do lookup
 
243
                 * in main socket hash table and lock on listening
 
244
                 * socket does not protect us more.
 
245
                 */
 
246
                __sk_add_backlog(child, skb);
 
247
        }
 
248
 
 
249
        bh_unlock_sock(child);
 
250
        sock_put(child);
 
251
        return ret;
 
252
}
 
253
 
 
254
EXPORT_SYMBOL_GPL(dccp_child_process);
 
255
 
 
256
void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
 
257
                         struct request_sock *rsk)
 
258
{
 
259
        DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
 
260
}
 
261
 
 
262
EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
 
263
 
 
264
int dccp_reqsk_init(struct request_sock *req,
 
265
                    struct dccp_sock const *dp, struct sk_buff const *skb)
 
266
{
 
267
        struct dccp_request_sock *dreq = dccp_rsk(req);
 
268
 
 
269
        inet_rsk(req)->rmt_port   = dccp_hdr(skb)->dccph_sport;
 
270
        inet_rsk(req)->loc_port   = dccp_hdr(skb)->dccph_dport;
 
271
        inet_rsk(req)->acked      = 0;
 
272
        dreq->dreq_timestamp_echo = 0;
 
273
 
 
274
        /* inherit feature negotiation options from listening socket */
 
275
        return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
 
276
}
 
277
 
 
278
EXPORT_SYMBOL_GPL(dccp_reqsk_init);