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