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