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2874c5fd 1// SPDX-License-Identifier: GPL-2.0-or-later
7c657876
ACM
2/*
3 * net/dccp/minisocks.c
4 *
5 * An implementation of the DCCP protocol
6 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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7 */
8
7c657876 9#include <linux/dccp.h>
5a0e3ad6 10#include <linux/gfp.h>
8a73cd09 11#include <linux/kernel.h>
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12#include <linux/skbuff.h>
13#include <linux/timer.h>
14
15#include <net/sock.h>
16#include <net/xfrm.h>
17#include <net/inet_timewait_sock.h>
18
ae31c339 19#include "ackvec.h"
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20#include "ccid.h"
21#include "dccp.h"
afe00251 22#include "feat.h"
7c657876 23
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24struct inet_timewait_death_row dccp_death_row = {
25 .sysctl_max_tw_buckets = NR_FILE * 2,
64cf1e5d 26 .hashinfo = &dccp_hashinfo,
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27};
28
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29EXPORT_SYMBOL_GPL(dccp_death_row);
30
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31void dccp_time_wait(struct sock *sk, int state, int timeo)
32{
789f558c 33 struct inet_timewait_sock *tw;
7c657876 34
789f558c 35 tw = inet_twsk_alloc(sk, &dccp_death_row, state);
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36
37 if (tw != NULL) {
38 const struct inet_connection_sock *icsk = inet_csk(sk);
39 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
dfd56b8b 40#if IS_ENABLED(CONFIG_IPV6)
3df80d93 41 if (tw->tw_family == PF_INET6) {
efe4208f
ED
42 tw->tw_v6_daddr = sk->sk_v6_daddr;
43 tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
9fe516ba 44 tw->tw_ipv6only = sk->sk_ipv6only;
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45 }
46#endif
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47
48 /* Get the TIME_WAIT timeout firing. */
49 if (timeo < rto)
50 timeo = rto;
51
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52 if (state == DCCP_TIME_WAIT)
53 timeo = DCCP_TIMEWAIT_LEN;
54
cfac7f83
ED
55 /* tw_timer is pinned, so we need to make sure BH are disabled
56 * in following section, otherwise timer handler could run before
57 * we complete the initialization.
58 */
59 local_bh_disable();
789f558c 60 inet_twsk_schedule(tw, timeo);
ec94c269
ED
61 /* Linkage updates.
62 * Note that access to tw after this point is illegal.
63 */
64 inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
cfac7f83 65 local_bh_enable();
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66 } else {
67 /* Sorry, if we're out of memory, just CLOSE this
68 * socket up. We've got bigger problems than
69 * non-graceful socket closings.
70 */
59348b19 71 DCCP_WARN("time wait bucket table overflow\n");
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72 }
73
74 dccp_done(sk);
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75}
76
54105f98 77struct sock *dccp_create_openreq_child(const struct sock *sk,
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78 const struct request_sock *req,
79 const struct sk_buff *skb)
80{
81 /*
82 * Step 3: Process LISTEN state
83 *
d83ca5ac
GR
84 * (* Generate a new socket and switch to that socket *)
85 * Set S := new socket for this port pair
7c657876 86 */
e56c57d0 87 struct sock *newsk = inet_csk_clone_lock(sk, req, GFP_ATOMIC);
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88
89 if (newsk != NULL) {
192b27ff 90 struct dccp_request_sock *dreq = dccp_rsk(req);
99c72ce0 91 struct inet_connection_sock *newicsk = inet_csk(newsk);
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92 struct dccp_sock *newdp = dccp_sk(newsk);
93
b4d4f7c7
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94 newdp->dccps_role = DCCP_ROLE_SERVER;
95 newdp->dccps_hc_rx_ackvec = NULL;
b637487e
TLSC
96 newdp->dccps_hc_rx_ccid = NULL;
97 newdp->dccps_hc_tx_ccid = NULL;
b4d4f7c7 98 newdp->dccps_service_list = NULL;
d9ea761f
LZ
99 newdp->dccps_hc_rx_ccid = NULL;
100 newdp->dccps_hc_tx_ccid = NULL;
b4d4f7c7
GR
101 newdp->dccps_service = dreq->dreq_service;
102 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
103 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
104 newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
7c657876 105
ac75773c 106 INIT_LIST_HEAD(&newdp->dccps_featneg);
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107 /*
108 * Step 3: Process LISTEN state
109 *
d83ca5ac
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110 * Choose S.ISS (initial seqno) or set from Init Cookies
111 * Initialize S.GAR := S.ISS
0b53d460
GR
112 * Set S.ISR, S.GSR from packet (or Init Cookies)
113 *
114 * Setting AWL/AWH and SWL/SWH happens as part of the feature
115 * activation below, as these windows all depend on the local
116 * and remote Sequence Window feature values (7.5.2).
03ace394 117 */
f541fb7e
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118 newdp->dccps_iss = dreq->dreq_iss;
119 newdp->dccps_gss = dreq->dreq_gss;
0b53d460 120 newdp->dccps_gar = newdp->dccps_iss;
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SJ
121 newdp->dccps_isr = dreq->dreq_isr;
122 newdp->dccps_gsr = dreq->dreq_gsr;
03ace394 123
192b27ff 124 /*
0b53d460 125 * Activate features: initialise CCIDs, sequence windows etc.
192b27ff
GR
126 */
127 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
94352d45 128 sk_free_unlock_clone(newsk);
192b27ff
GR
129 return NULL;
130 }
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131 dccp_init_xmit_timers(newsk);
132
aa62d76b 133 __DCCP_INC_STATS(DCCP_MIB_PASSIVEOPENS);
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134 }
135 return newsk;
136}
137
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138EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
139
8109b02b 140/*
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141 * Process an incoming packet for RESPOND sockets represented
142 * as an request_sock.
143 */
144struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
52452c54 145 struct request_sock *req)
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146{
147 struct sock *child = NULL;
8109616e 148 struct dccp_request_sock *dreq = dccp_rsk(req);
5e0724d0 149 bool own_req;
7c657876 150
62f8f4d9
ED
151 /* TCP/DCCP listeners became lockless.
152 * DCCP stores complex state in its request_sock, so we need
153 * a protection for them, now this code runs without being protected
154 * by the parent (listener) lock.
155 */
156 spin_lock_bh(&dreq->dreq_lock);
157
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158 /* Check for retransmitted REQUEST */
159 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
7c657876 160
f541fb7e 161 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) {
7c657876 162 dccp_pr_debug("Retransmitted REQUEST\n");
f541fb7e 163 dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq;
e11d9d30
GR
164 /*
165 * Send another RESPONSE packet
166 * To protect against Request floods, increment retrans
167 * counter (backoff, monitored by dccp_response_timer).
168 */
e6c022a4 169 inet_rtx_syn_ack(sk, req);
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170 }
171 /* Network Duplicate, discard packet */
62f8f4d9 172 goto out;
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173 }
174
175 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
176
177 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
178 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
179 goto drop;
180
181 /* Invalid ACK */
f541fb7e
SJ
182 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
183 dreq->dreq_iss, dreq->dreq_gss)) {
7690af3f 184 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
f541fb7e 185 "dreq_iss=%llu, dreq_gss=%llu\n",
f6ccf554
DM
186 (unsigned long long)
187 DCCP_SKB_CB(skb)->dccpd_ack_seq,
f541fb7e
SJ
188 (unsigned long long) dreq->dreq_iss,
189 (unsigned long long) dreq->dreq_gss);
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190 goto drop;
191 }
192
8109616e
GR
193 if (dccp_parse_options(sk, dreq, skb))
194 goto drop;
195
5e0724d0
ED
196 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL,
197 req, &own_req);
62f8f4d9
ED
198 if (child) {
199 child = inet_csk_complete_hashdance(sk, child, req, own_req);
200 goto out;
201 }
5e0724d0 202
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203 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
204drop:
205 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
cfb6eeb4 206 req->rsk_ops->send_reset(sk, skb);
7c657876 207
52452c54 208 inet_csk_reqsk_queue_drop(sk, req);
62f8f4d9
ED
209out:
210 spin_unlock_bh(&dreq->dreq_lock);
211 return child;
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212}
213
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214EXPORT_SYMBOL_GPL(dccp_check_req);
215
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216/*
217 * Queue segment on the new socket if the new socket is active,
218 * otherwise we just shortcircuit this and continue with
219 * the new socket.
220 */
221int dccp_child_process(struct sock *parent, struct sock *child,
222 struct sk_buff *skb)
3283ff2e 223 __releases(child)
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224{
225 int ret = 0;
226 const int state = child->sk_state;
227
228 if (!sock_owned_by_user(child)) {
7690af3f
ACM
229 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
230 skb->len);
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231
232 /* Wakeup parent, send SIGIO */
233 if (state == DCCP_RESPOND && child->sk_state != state)
676d2369 234 parent->sk_data_ready(parent);
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235 } else {
236 /* Alas, it is possible again, because we do lookup
237 * in main socket hash table and lock on listening
238 * socket does not protect us more.
239 */
a3a858ff 240 __sk_add_backlog(child, skb);
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241 }
242
243 bh_unlock_sock(child);
244 sock_put(child);
245 return ret;
246}
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247
248EXPORT_SYMBOL_GPL(dccp_child_process);
8a73cd09 249
a00e7444 250void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
6edafaaf 251 struct request_sock *rsk)
8a73cd09 252{
59348b19 253 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
8a73cd09
GR
254}
255
256EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
cf557926 257
ac75773c
GR
258int dccp_reqsk_init(struct request_sock *req,
259 struct dccp_sock const *dp, struct sk_buff const *skb)
cf557926 260{
b4d4f7c7
GR
261 struct dccp_request_sock *dreq = dccp_rsk(req);
262
62f8f4d9 263 spin_lock_init(&dreq->dreq_lock);
b44084c2
ED
264 inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport;
265 inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport);
266 inet_rsk(req)->acked = 0;
267 dreq->dreq_timestamp_echo = 0;
ac75773c
GR
268
269 /* inherit feature negotiation options from listening socket */
270 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
cf557926
GR
271}
272
273EXPORT_SYMBOL_GPL(dccp_reqsk_init);