1 // SPDX-License-Identifier: GPL-2.0-or-later <<
2 /* Service connection management 1 /* Service connection management
3 * 2 *
4 * Copyright (C) 2016 Red Hat, Inc. All Rights 3 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.c 4 * Written by David Howells (dhowells@redhat.com)
>> 5 *
>> 6 * This program is free software; you can redistribute it and/or
>> 7 * modify it under the terms of the GNU General Public Licence
>> 8 * as published by the Free Software Foundation; either version
>> 9 * 2 of the Licence, or (at your option) any later version.
6 */ 10 */
7 11
8 #include <linux/slab.h> 12 #include <linux/slab.h>
9 #include "ar-internal.h" 13 #include "ar-internal.h"
10 14
11 /* 15 /*
12 * Find a service connection under RCU conditi 16 * Find a service connection under RCU conditions.
13 * 17 *
14 * We could use a hash table, but that is subj 18 * We could use a hash table, but that is subject to bucket stuffing by an
15 * attacker as the client gets to pick the epo 19 * attacker as the client gets to pick the epoch and cid values and would know
16 * the hash function. So, instead, we use a h 20 * the hash function. So, instead, we use a hash table for the peer and from
17 * that an rbtree to find the service connecti 21 * that an rbtree to find the service connection. Under ordinary circumstances
18 * it might be slower than a large hash table, 22 * it might be slower than a large hash table, but it is at least limited in
19 * depth. 23 * depth.
20 */ 24 */
21 struct rxrpc_connection *rxrpc_find_service_co 25 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer,
22 26 struct sk_buff *skb)
23 { 27 {
24 struct rxrpc_connection *conn = NULL; 28 struct rxrpc_connection *conn = NULL;
25 struct rxrpc_conn_proto k; 29 struct rxrpc_conn_proto k;
26 struct rxrpc_skb_priv *sp = rxrpc_skb( 30 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
27 struct rb_node *p; 31 struct rb_node *p;
28 unsigned int seq = 1; !! 32 unsigned int seq = 0;
29 33
30 k.epoch = sp->hdr.epoch; 34 k.epoch = sp->hdr.epoch;
31 k.cid = sp->hdr.cid & RXRPC_CIDMASK; 35 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
32 36
33 do { 37 do {
34 /* Unfortunately, rbtree walki 38 /* Unfortunately, rbtree walking doesn't give reliable results
35 * under just the RCU read loc 39 * under just the RCU read lock, so we have to check for
36 * changes. 40 * changes.
37 */ 41 */
38 seq++; /* 2 on the 1st/lockles <<
39 read_seqbegin_or_lock(&peer->s 42 read_seqbegin_or_lock(&peer->service_conn_lock, &seq);
40 43
41 p = rcu_dereference_raw(peer-> 44 p = rcu_dereference_raw(peer->service_conns.rb_node);
42 while (p) { 45 while (p) {
43 conn = rb_entry(p, str 46 conn = rb_entry(p, struct rxrpc_connection, service_node);
44 47
45 if (conn->proto.index_ 48 if (conn->proto.index_key < k.index_key)
46 p = rcu_derefe 49 p = rcu_dereference_raw(p->rb_left);
47 else if (conn->proto.i 50 else if (conn->proto.index_key > k.index_key)
48 p = rcu_derefe 51 p = rcu_dereference_raw(p->rb_right);
49 else 52 else
50 break; !! 53 goto done;
51 conn = NULL; 54 conn = NULL;
52 } 55 }
53 } while (need_seqretry(&peer->service_ 56 } while (need_seqretry(&peer->service_conn_lock, seq));
54 57
>> 58 done:
55 done_seqretry(&peer->service_conn_lock 59 done_seqretry(&peer->service_conn_lock, seq);
56 _leave(" = %d", conn ? conn->debug_id 60 _leave(" = %d", conn ? conn->debug_id : -1);
57 return conn; 61 return conn;
58 } 62 }
59 63
60 /* 64 /*
61 * Insert a service connection into a peer's t 65 * Insert a service connection into a peer's tree, thereby making it a target
62 * for incoming packets. 66 * for incoming packets.
63 */ 67 */
64 static void rxrpc_publish_service_conn(struct 68 static void rxrpc_publish_service_conn(struct rxrpc_peer *peer,
65 struct 69 struct rxrpc_connection *conn)
66 { 70 {
67 struct rxrpc_connection *cursor = NULL 71 struct rxrpc_connection *cursor = NULL;
68 struct rxrpc_conn_proto k = conn->prot 72 struct rxrpc_conn_proto k = conn->proto;
69 struct rb_node **pp, *parent; 73 struct rb_node **pp, *parent;
70 74
71 write_seqlock(&peer->service_conn_lock !! 75 write_seqlock_bh(&peer->service_conn_lock);
72 76
73 pp = &peer->service_conns.rb_node; 77 pp = &peer->service_conns.rb_node;
74 parent = NULL; 78 parent = NULL;
75 while (*pp) { 79 while (*pp) {
76 parent = *pp; 80 parent = *pp;
77 cursor = rb_entry(parent, 81 cursor = rb_entry(parent,
78 struct rxrpc 82 struct rxrpc_connection, service_node);
79 83
80 if (cursor->proto.index_key < 84 if (cursor->proto.index_key < k.index_key)
81 pp = &(*pp)->rb_left; 85 pp = &(*pp)->rb_left;
82 else if (cursor->proto.index_k 86 else if (cursor->proto.index_key > k.index_key)
83 pp = &(*pp)->rb_right; 87 pp = &(*pp)->rb_right;
84 else 88 else
85 goto found_extant_conn 89 goto found_extant_conn;
86 } 90 }
87 91
88 rb_link_node_rcu(&conn->service_node, 92 rb_link_node_rcu(&conn->service_node, parent, pp);
89 rb_insert_color(&conn->service_node, & 93 rb_insert_color(&conn->service_node, &peer->service_conns);
90 conn_published: 94 conn_published:
91 set_bit(RXRPC_CONN_IN_SERVICE_CONNS, & 95 set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags);
92 write_sequnlock(&peer->service_conn_lo !! 96 write_sequnlock_bh(&peer->service_conn_lock);
93 _leave(" = %d [new]", conn->debug_id); 97 _leave(" = %d [new]", conn->debug_id);
94 return; 98 return;
95 99
96 found_extant_conn: 100 found_extant_conn:
97 if (refcount_read(&cursor->ref) == 0) !! 101 if (atomic_read(&cursor->usage) == 0)
98 goto replace_old_connection; 102 goto replace_old_connection;
99 write_sequnlock(&peer->service_conn_lo !! 103 write_sequnlock_bh(&peer->service_conn_lock);
100 /* We should not be able to get here. 104 /* We should not be able to get here. rxrpc_incoming_connection() is
101 * called in a non-reentrant context, 105 * called in a non-reentrant context, so there can't be a race to
102 * insert a new connection. 106 * insert a new connection.
103 */ 107 */
104 BUG(); 108 BUG();
105 109
106 replace_old_connection: 110 replace_old_connection:
107 /* The old connection is from an outda 111 /* The old connection is from an outdated epoch. */
108 _debug("replace conn"); 112 _debug("replace conn");
109 rb_replace_node_rcu(&cursor->service_n 113 rb_replace_node_rcu(&cursor->service_node,
110 &conn->service_nod 114 &conn->service_node,
111 &peer->service_con 115 &peer->service_conns);
112 clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, 116 clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &cursor->flags);
113 goto conn_published; 117 goto conn_published;
114 } 118 }
115 119
116 /* 120 /*
117 * Preallocate a service connection. The conn 121 * Preallocate a service connection. The connection is placed on the proc and
118 * reap lists so that we don't have to get the 122 * reap lists so that we don't have to get the lock from BH context.
119 */ 123 */
120 struct rxrpc_connection *rxrpc_prealloc_servic !! 124 struct rxrpc_connection *rxrpc_prealloc_service_connection(gfp_t gfp)
121 <<
122 { 125 {
123 struct rxrpc_connection *conn = rxrpc_ !! 126 struct rxrpc_connection *conn = rxrpc_alloc_connection(gfp);
124 127
125 if (conn) { 128 if (conn) {
126 /* We maintain an extra ref on 129 /* We maintain an extra ref on the connection whilst it is on
127 * the rxrpc_connections list. 130 * the rxrpc_connections list.
128 */ 131 */
129 conn->state = RXRPC_CONN_SERVI 132 conn->state = RXRPC_CONN_SERVICE_PREALLOC;
130 refcount_set(&conn->ref, 2); !! 133 atomic_set(&conn->usage, 2);
131 <<
132 atomic_inc(&rxnet->nr_conns); <<
133 write_lock(&rxnet->conn_lock); <<
134 list_add_tail(&conn->link, &rx <<
135 list_add_tail(&conn->proc_link <<
136 write_unlock(&rxnet->conn_lock <<
137 134
138 rxrpc_see_connection(conn, rxr !! 135 write_lock(&rxrpc_connection_lock);
>> 136 list_add_tail(&conn->link, &rxrpc_connections);
>> 137 list_add_tail(&conn->proc_link, &rxrpc_connection_proc_list);
>> 138 write_unlock(&rxrpc_connection_lock);
>> 139
>> 140 trace_rxrpc_conn(conn, rxrpc_conn_new_service,
>> 141 atomic_read(&conn->usage),
>> 142 __builtin_return_address(0));
139 } 143 }
140 144
141 return conn; 145 return conn;
142 } 146 }
143 147
144 /* 148 /*
145 * Set up an incoming connection. This is cal 149 * Set up an incoming connection. This is called in BH context with the RCU
146 * read lock held. 150 * read lock held.
147 */ 151 */
148 void rxrpc_new_incoming_connection(struct rxrp !! 152 void rxrpc_new_incoming_connection(struct rxrpc_connection *conn,
149 struct rxrp <<
150 const struc <<
151 struct sk_b 153 struct sk_buff *skb)
152 { 154 {
153 struct rxrpc_skb_priv *sp = rxrpc_skb( 155 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
154 156
155 _enter(""); 157 _enter("");
156 158
157 conn->proto.epoch = sp->hdr.epoc 159 conn->proto.epoch = sp->hdr.epoch;
158 conn->proto.cid = sp->hdr.cid 160 conn->proto.cid = sp->hdr.cid & RXRPC_CIDMASK;
159 conn->orig_service_id = sp->hdr.serv !! 161 conn->params.service_id = sp->hdr.serviceId;
160 conn->service_id = sp->hdr.serv <<
161 conn->security_ix = sp->hdr.secu 162 conn->security_ix = sp->hdr.securityIndex;
162 conn->out_clientflag = 0; 163 conn->out_clientflag = 0;
163 conn->security = sec; <<
164 if (conn->security_ix) 164 if (conn->security_ix)
165 conn->state = RXRPC_CONN_S 165 conn->state = RXRPC_CONN_SERVICE_UNSECURED;
166 else 166 else
167 conn->state = RXRPC_CONN_S 167 conn->state = RXRPC_CONN_SERVICE;
168 168
169 /* See if we should upgrade the servic <<
170 * first packet on a new connection. <<
171 * subsequent calls on that connection <<
172 */ <<
173 if (sp->hdr.userStatus == RXRPC_USERST <<
174 conn->service_id == rx->service_up <<
175 conn->service_id = rx->service <<
176 <<
177 atomic_set(&conn->active, 1); <<
178 <<
179 /* Make the connection a target for in 169 /* Make the connection a target for incoming packets. */
180 rxrpc_publish_service_conn(conn->peer, !! 170 rxrpc_publish_service_conn(conn->params.peer, conn);
>> 171
>> 172 _net("CONNECTION new %d {%x}", conn->debug_id, conn->proto.cid);
181 } 173 }
182 174
183 /* 175 /*
184 * Remove the service connection from the peer 176 * Remove the service connection from the peer's tree, thereby removing it as a
185 * target for incoming packets. 177 * target for incoming packets.
186 */ 178 */
187 void rxrpc_unpublish_service_conn(struct rxrpc 179 void rxrpc_unpublish_service_conn(struct rxrpc_connection *conn)
188 { 180 {
189 struct rxrpc_peer *peer = conn->peer; !! 181 struct rxrpc_peer *peer = conn->params.peer;
190 182
191 write_seqlock(&peer->service_conn_lock !! 183 write_seqlock_bh(&peer->service_conn_lock);
192 if (test_and_clear_bit(RXRPC_CONN_IN_S 184 if (test_and_clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags))
193 rb_erase(&conn->service_node, 185 rb_erase(&conn->service_node, &peer->service_conns);
194 write_sequnlock(&peer->service_conn_lo !! 186 write_sequnlock_bh(&peer->service_conn_lock);
195 } 187 }
196 188
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