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7c657876 ACM |
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/config.h> | |
14 | #include <linux/dccp.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 "ccid.h" | |
23 | #include "dccp.h" | |
24 | ||
64cf1e5d ACM |
25 | struct inet_timewait_death_row dccp_death_row = { |
26 | .sysctl_max_tw_buckets = NR_FILE * 2, | |
27 | .period = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS, | |
28 | .death_lock = SPIN_LOCK_UNLOCKED, | |
29 | .hashinfo = &dccp_hashinfo, | |
30 | .tw_timer = TIMER_INITIALIZER(inet_twdr_hangman, 0, | |
31 | (unsigned long)&dccp_death_row), | |
32 | .twkill_work = __WORK_INITIALIZER(dccp_death_row.twkill_work, | |
33 | inet_twdr_twkill_work, | |
34 | &dccp_death_row), | |
35 | /* Short-time timewait calendar */ | |
36 | ||
37 | .twcal_hand = -1, | |
38 | .twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0, | |
39 | (unsigned long)&dccp_death_row), | |
40 | }; | |
41 | ||
7c657876 ACM |
42 | void dccp_time_wait(struct sock *sk, int state, int timeo) |
43 | { | |
64cf1e5d | 44 | struct inet_timewait_sock *tw = NULL; |
7c657876 | 45 | |
64cf1e5d ACM |
46 | if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets) |
47 | tw = inet_twsk_alloc(sk, state); | |
48 | ||
49 | if (tw != NULL) { | |
50 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
51 | const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); | |
52 | ||
53 | /* Linkage updates. */ | |
54 | __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); | |
55 | ||
56 | /* Get the TIME_WAIT timeout firing. */ | |
57 | if (timeo < rto) | |
58 | timeo = rto; | |
59 | ||
60 | tw->tw_timeout = DCCP_TIMEWAIT_LEN; | |
61 | if (state == DCCP_TIME_WAIT) | |
62 | timeo = DCCP_TIMEWAIT_LEN; | |
63 | ||
64 | inet_twsk_schedule(tw, &dccp_death_row, timeo, | |
65 | DCCP_TIMEWAIT_LEN); | |
66 | inet_twsk_put(tw); | |
67 | } else { | |
68 | /* Sorry, if we're out of memory, just CLOSE this | |
69 | * socket up. We've got bigger problems than | |
70 | * non-graceful socket closings. | |
71 | */ | |
7690af3f ACM |
72 | LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket " |
73 | "table overflow\n"); | |
64cf1e5d ACM |
74 | } |
75 | ||
76 | dccp_done(sk); | |
7c657876 ACM |
77 | } |
78 | ||
79 | struct sock *dccp_create_openreq_child(struct sock *sk, | |
80 | const struct request_sock *req, | |
81 | const struct sk_buff *skb) | |
82 | { | |
83 | /* | |
84 | * Step 3: Process LISTEN state | |
85 | * | |
86 | * // Generate a new socket and switch to that socket | |
87 | * Set S := new socket for this port pair | |
88 | */ | |
89 | struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); | |
90 | ||
91 | if (newsk != NULL) { | |
92 | const struct dccp_request_sock *dreq = dccp_rsk(req); | |
93 | struct inet_connection_sock *newicsk = inet_csk(sk); | |
94 | struct dccp_sock *newdp = dccp_sk(newsk); | |
95 | ||
96 | newdp->dccps_hc_rx_ackpkts = NULL; | |
97 | newdp->dccps_role = DCCP_ROLE_SERVER; | |
64cf1e5d | 98 | newicsk->icsk_rto = DCCP_TIMEOUT_INIT; |
7c657876 ACM |
99 | |
100 | if (newdp->dccps_options.dccpo_send_ack_vector) { | |
7690af3f ACM |
101 | newdp->dccps_hc_rx_ackpkts = |
102 | dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN, | |
103 | GFP_ATOMIC); | |
7c657876 | 104 | /* |
7690af3f ACM |
105 | * XXX: We're using the same CCIDs set on the parent, |
106 | * i.e. sk_clone copied the master sock and left the | |
107 | * CCID pointers for this child, that is why we do the | |
108 | * __ccid_get calls. | |
7c657876 ACM |
109 | */ |
110 | if (unlikely(newdp->dccps_hc_rx_ackpkts == NULL)) | |
111 | goto out_free; | |
112 | } | |
113 | ||
7690af3f ACM |
114 | if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid, |
115 | newsk) != 0 || | |
116 | ccid_hc_tx_init(newdp->dccps_hc_tx_ccid, | |
117 | newsk) != 0)) { | |
7c657876 ACM |
118 | dccp_ackpkts_free(newdp->dccps_hc_rx_ackpkts); |
119 | ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk); | |
120 | ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk); | |
121 | out_free: | |
122 | /* It is still raw copy of parent, so invalidate | |
123 | * destructor and make plain sk_free() */ | |
124 | newsk->sk_destruct = NULL; | |
125 | sk_free(newsk); | |
126 | return NULL; | |
127 | } | |
128 | ||
129 | __ccid_get(newdp->dccps_hc_rx_ccid); | |
130 | __ccid_get(newdp->dccps_hc_tx_ccid); | |
131 | ||
132 | /* | |
133 | * Step 3: Process LISTEN state | |
134 | * | |
135 | * Choose S.ISS (initial seqno) or set from Init Cookie | |
7690af3f ACM |
136 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init |
137 | * Cookie | |
7c657876 ACM |
138 | */ |
139 | ||
140 | /* See dccp_v4_conn_request */ | |
141 | newdp->dccps_options.dccpo_sequence_window = req->rcv_wnd; | |
142 | ||
143 | newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr; | |
144 | dccp_update_gsr(newsk, dreq->dreq_isr); | |
145 | ||
146 | newdp->dccps_iss = dreq->dreq_iss; | |
147 | dccp_update_gss(newsk, dreq->dreq_iss); | |
148 | ||
03ace394 ACM |
149 | /* |
150 | * SWL and AWL are initially adjusted so that they are not less than | |
151 | * the initial Sequence Numbers received and sent, respectively: | |
152 | * SWL := max(GSR + 1 - floor(W/4), ISR), | |
153 | * AWL := max(GSS - W' + 1, ISS). | |
154 | * These adjustments MUST be applied only at the beginning of the | |
155 | * connection. | |
156 | */ | |
157 | dccp_set_seqno(&newdp->dccps_swl, | |
158 | max48(newdp->dccps_swl, newdp->dccps_isr)); | |
159 | dccp_set_seqno(&newdp->dccps_awl, | |
160 | max48(newdp->dccps_awl, newdp->dccps_iss)); | |
161 | ||
7c657876 ACM |
162 | dccp_init_xmit_timers(newsk); |
163 | ||
164 | DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); | |
165 | } | |
166 | return newsk; | |
167 | } | |
168 | ||
169 | /* | |
170 | * Process an incoming packet for RESPOND sockets represented | |
171 | * as an request_sock. | |
172 | */ | |
173 | struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, | |
174 | struct request_sock *req, | |
175 | struct request_sock **prev) | |
176 | { | |
177 | struct sock *child = NULL; | |
178 | ||
179 | /* Check for retransmitted REQUEST */ | |
180 | if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { | |
7690af3f ACM |
181 | if (after48(DCCP_SKB_CB(skb)->dccpd_seq, |
182 | dccp_rsk(req)->dreq_isr)) { | |
7c657876 ACM |
183 | struct dccp_request_sock *dreq = dccp_rsk(req); |
184 | ||
185 | dccp_pr_debug("Retransmitted REQUEST\n"); | |
186 | /* Send another RESPONSE packet */ | |
187 | dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1); | |
7690af3f ACM |
188 | dccp_set_seqno(&dreq->dreq_isr, |
189 | DCCP_SKB_CB(skb)->dccpd_seq); | |
7c657876 ACM |
190 | req->rsk_ops->rtx_syn_ack(sk, req, NULL); |
191 | } | |
192 | /* Network Duplicate, discard packet */ | |
193 | return NULL; | |
194 | } | |
195 | ||
196 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; | |
197 | ||
198 | if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && | |
199 | dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) | |
200 | goto drop; | |
201 | ||
202 | /* Invalid ACK */ | |
203 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) { | |
7690af3f ACM |
204 | dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " |
205 | "dreq_iss=%llu\n", | |
f6ccf554 DM |
206 | (unsigned long long) |
207 | DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
208 | (unsigned long long) | |
209 | dccp_rsk(req)->dreq_iss); | |
7c657876 ACM |
210 | goto drop; |
211 | } | |
212 | ||
213 | child = dccp_v4_request_recv_sock(sk, skb, req, NULL); | |
214 | if (child == NULL) | |
215 | goto listen_overflow; | |
216 | ||
217 | /* FIXME: deal with options */ | |
218 | ||
219 | inet_csk_reqsk_queue_unlink(sk, req, prev); | |
220 | inet_csk_reqsk_queue_removed(sk, req); | |
221 | inet_csk_reqsk_queue_add(sk, req, child); | |
222 | out: | |
223 | return child; | |
224 | listen_overflow: | |
225 | dccp_pr_debug("listen_overflow!\n"); | |
226 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; | |
227 | drop: | |
228 | if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) | |
229 | req->rsk_ops->send_reset(skb); | |
230 | ||
231 | inet_csk_reqsk_queue_drop(sk, req, prev); | |
232 | goto out; | |
233 | } | |
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)) { | |
7690af3f ACM |
247 | ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), |
248 | skb->len); | |
7c657876 ACM |
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 | } |