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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_service = dreq->dreq_service;
98 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
99 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
100 newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
101
102 INIT_LIST_HEAD(&newdp->dccps_featneg);
103 /*
104 * Step 3: Process LISTEN state
105 *
106 * Choose S.ISS (initial seqno) or set from Init Cookies
107 * Initialize S.GAR := S.ISS
108 * Set S.ISR, S.GSR from packet (or Init Cookies)
109 *
110 * Setting AWL/AWH and SWL/SWH happens as part of the feature
111 * activation below, as these windows all depend on the local
112 * and remote Sequence Window feature values (7.5.2).
113 */
114 newdp->dccps_iss = dreq->dreq_iss;
115 newdp->dccps_gss = dreq->dreq_gss;
116 newdp->dccps_gar = newdp->dccps_iss;
117 newdp->dccps_isr = dreq->dreq_isr;
118 newdp->dccps_gsr = dreq->dreq_gsr;
119
120 /*
121 * Activate features: initialise CCIDs, sequence windows etc.
122 */
123 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
124 sk_free_unlock_clone(newsk);
125 return NULL;
126 }
127 dccp_init_xmit_timers(newsk);
128
129 __DCCP_INC_STATS(DCCP_MIB_PASSIVEOPENS);
130 }
131 return newsk;
132}
133
134EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
135
136/*
137 * Process an incoming packet for RESPOND sockets represented
138 * as an request_sock.
139 */
140struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
141 struct request_sock *req)
142{
143 struct sock *child = NULL;
144 struct dccp_request_sock *dreq = dccp_rsk(req);
145 bool own_req;
146
147 /* TCP/DCCP listeners became lockless.
148 * DCCP stores complex state in its request_sock, so we need
149 * a protection for them, now this code runs without being protected
150 * by the parent (listener) lock.
151 */
152 spin_lock_bh(&dreq->dreq_lock);
153
154 /* Check for retransmitted REQUEST */
155 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
156
157 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) {
158 dccp_pr_debug("Retransmitted REQUEST\n");
159 dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq;
160 /*
161 * Send another RESPONSE packet
162 * To protect against Request floods, increment retrans
163 * counter (backoff, monitored by dccp_response_timer).
164 */
165 inet_rtx_syn_ack(sk, req);
166 }
167 /* Network Duplicate, discard packet */
168 goto out;
169 }
170
171 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
172
173 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
174 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
175 goto drop;
176
177 /* Invalid ACK */
178 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
179 dreq->dreq_iss, dreq->dreq_gss)) {
180 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
181 "dreq_iss=%llu, dreq_gss=%llu\n",
182 (unsigned long long)
183 DCCP_SKB_CB(skb)->dccpd_ack_seq,
184 (unsigned long long) dreq->dreq_iss,
185 (unsigned long long) dreq->dreq_gss);
186 goto drop;
187 }
188
189 if (dccp_parse_options(sk, dreq, skb))
190 goto drop;
191
192 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL,
193 req, &own_req);
194 if (child) {
195 child = inet_csk_complete_hashdance(sk, child, req, own_req);
196 goto out;
197 }
198
199 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
200drop:
201 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
202 req->rsk_ops->send_reset(sk, skb);
203
204 inet_csk_reqsk_queue_drop(sk, req);
205out:
206 spin_unlock_bh(&dreq->dreq_lock);
207 return child;
208}
209
210EXPORT_SYMBOL_GPL(dccp_check_req);
211
212/*
213 * Queue segment on the new socket if the new socket is active,
214 * otherwise we just shortcircuit this and continue with
215 * the new socket.
216 */
217int dccp_child_process(struct sock *parent, struct sock *child,
218 struct sk_buff *skb)
219{
220 int ret = 0;
221 const int state = child->sk_state;
222
223 if (!sock_owned_by_user(child)) {
224 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
225 skb->len);
226
227 /* Wakeup parent, send SIGIO */
228 if (state == DCCP_RESPOND && child->sk_state != state)
229 parent->sk_data_ready(parent);
230 } else {
231 /* Alas, it is possible again, because we do lookup
232 * in main socket hash table and lock on listening
233 * socket does not protect us more.
234 */
235 __sk_add_backlog(child, skb);
236 }
237
238 bh_unlock_sock(child);
239 sock_put(child);
240 return ret;
241}
242
243EXPORT_SYMBOL_GPL(dccp_child_process);
244
245void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
246 struct request_sock *rsk)
247{
248 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
249}
250
251EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
252
253int dccp_reqsk_init(struct request_sock *req,
254 struct dccp_sock const *dp, struct sk_buff const *skb)
255{
256 struct dccp_request_sock *dreq = dccp_rsk(req);
257
258 spin_lock_init(&dreq->dreq_lock);
259 inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport;
260 inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport);
261 inet_rsk(req)->acked = 0;
262 dreq->dreq_timestamp_echo = 0;
263
264 /* inherit feature negotiation options from listening socket */
265 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
266}
267
268EXPORT_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 sk_free(newsk);
126 return NULL;
127 }
128 dccp_init_xmit_timers(newsk);
129
130 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
131 }
132 return newsk;
133}
134
135EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
136
137/*
138 * Process an incoming packet for RESPOND sockets represented
139 * as an request_sock.
140 */
141struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
142 struct request_sock *req)
143{
144 struct sock *child = NULL;
145 struct dccp_request_sock *dreq = dccp_rsk(req);
146 bool own_req;
147
148 /* Check for retransmitted REQUEST */
149 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
150
151 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) {
152 dccp_pr_debug("Retransmitted REQUEST\n");
153 dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq;
154 /*
155 * Send another RESPONSE packet
156 * To protect against Request floods, increment retrans
157 * counter (backoff, monitored by dccp_response_timer).
158 */
159 inet_rtx_syn_ack(sk, req);
160 }
161 /* Network Duplicate, discard packet */
162 return NULL;
163 }
164
165 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
166
167 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
168 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
169 goto drop;
170
171 /* Invalid ACK */
172 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
173 dreq->dreq_iss, dreq->dreq_gss)) {
174 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
175 "dreq_iss=%llu, dreq_gss=%llu\n",
176 (unsigned long long)
177 DCCP_SKB_CB(skb)->dccpd_ack_seq,
178 (unsigned long long) dreq->dreq_iss,
179 (unsigned long long) dreq->dreq_gss);
180 goto drop;
181 }
182
183 if (dccp_parse_options(sk, dreq, skb))
184 goto drop;
185
186 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL,
187 req, &own_req);
188 if (!child)
189 goto listen_overflow;
190
191 return inet_csk_complete_hashdance(sk, child, req, own_req);
192
193listen_overflow:
194 dccp_pr_debug("listen_overflow!\n");
195 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
196drop:
197 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
198 req->rsk_ops->send_reset(sk, skb);
199
200 inet_csk_reqsk_queue_drop(sk, req);
201 return NULL;
202}
203
204EXPORT_SYMBOL_GPL(dccp_check_req);
205
206/*
207 * Queue segment on the new socket if the new socket is active,
208 * otherwise we just shortcircuit this and continue with
209 * the new socket.
210 */
211int dccp_child_process(struct sock *parent, struct sock *child,
212 struct sk_buff *skb)
213{
214 int ret = 0;
215 const int state = child->sk_state;
216
217 if (!sock_owned_by_user(child)) {
218 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
219 skb->len);
220
221 /* Wakeup parent, send SIGIO */
222 if (state == DCCP_RESPOND && child->sk_state != state)
223 parent->sk_data_ready(parent);
224 } else {
225 /* Alas, it is possible again, because we do lookup
226 * in main socket hash table and lock on listening
227 * socket does not protect us more.
228 */
229 __sk_add_backlog(child, skb);
230 }
231
232 bh_unlock_sock(child);
233 sock_put(child);
234 return ret;
235}
236
237EXPORT_SYMBOL_GPL(dccp_child_process);
238
239void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
240 struct request_sock *rsk)
241{
242 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
243}
244
245EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
246
247int dccp_reqsk_init(struct request_sock *req,
248 struct dccp_sock const *dp, struct sk_buff const *skb)
249{
250 struct dccp_request_sock *dreq = dccp_rsk(req);
251
252 inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport;
253 inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport);
254 inet_rsk(req)->acked = 0;
255 dreq->dreq_timestamp_echo = 0;
256
257 /* inherit feature negotiation options from listening socket */
258 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
259}
260
261EXPORT_SYMBOL_GPL(dccp_reqsk_init);