1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Service connection management 2 /* Service connection management
3 * 3 *
4 * Copyright (C) 2016 Red Hat, Inc. All Rights 4 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.c 5 * Written by David Howells (dhowells@redhat.com)
6 */ 6 */
7 7
8 #include <linux/slab.h> 8 #include <linux/slab.h>
9 #include "ar-internal.h" 9 #include "ar-internal.h"
10 10
>> 11 static struct rxrpc_bundle rxrpc_service_dummy_bundle = {
>> 12 .usage = ATOMIC_INIT(1),
>> 13 .debug_id = UINT_MAX,
>> 14 .channel_lock = __SPIN_LOCK_UNLOCKED(&rxrpc_service_dummy_bundle.channel_lock),
>> 15 };
>> 16
11 /* 17 /*
12 * Find a service connection under RCU conditi 18 * Find a service connection under RCU conditions.
13 * 19 *
14 * We could use a hash table, but that is subj 20 * 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 21 * 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 22 * the hash function. So, instead, we use a hash table for the peer and from
17 * that an rbtree to find the service connecti 23 * that an rbtree to find the service connection. Under ordinary circumstances
18 * it might be slower than a large hash table, 24 * it might be slower than a large hash table, but it is at least limited in
19 * depth. 25 * depth.
20 */ 26 */
21 struct rxrpc_connection *rxrpc_find_service_co 27 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer,
22 28 struct sk_buff *skb)
23 { 29 {
24 struct rxrpc_connection *conn = NULL; 30 struct rxrpc_connection *conn = NULL;
25 struct rxrpc_conn_proto k; 31 struct rxrpc_conn_proto k;
26 struct rxrpc_skb_priv *sp = rxrpc_skb( 32 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
27 struct rb_node *p; 33 struct rb_node *p;
28 unsigned int seq = 1; !! 34 unsigned int seq = 0;
29 35
30 k.epoch = sp->hdr.epoch; 36 k.epoch = sp->hdr.epoch;
31 k.cid = sp->hdr.cid & RXRPC_CIDMASK; 37 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
32 38
33 do { 39 do {
34 /* Unfortunately, rbtree walki 40 /* Unfortunately, rbtree walking doesn't give reliable results
35 * under just the RCU read loc 41 * under just the RCU read lock, so we have to check for
36 * changes. 42 * changes.
37 */ 43 */
38 seq++; /* 2 on the 1st/lockles <<
39 read_seqbegin_or_lock(&peer->s 44 read_seqbegin_or_lock(&peer->service_conn_lock, &seq);
40 45
41 p = rcu_dereference_raw(peer-> 46 p = rcu_dereference_raw(peer->service_conns.rb_node);
42 while (p) { 47 while (p) {
43 conn = rb_entry(p, str 48 conn = rb_entry(p, struct rxrpc_connection, service_node);
44 49
45 if (conn->proto.index_ 50 if (conn->proto.index_key < k.index_key)
46 p = rcu_derefe 51 p = rcu_dereference_raw(p->rb_left);
47 else if (conn->proto.i 52 else if (conn->proto.index_key > k.index_key)
48 p = rcu_derefe 53 p = rcu_dereference_raw(p->rb_right);
49 else 54 else
50 break; 55 break;
51 conn = NULL; 56 conn = NULL;
52 } 57 }
53 } while (need_seqretry(&peer->service_ 58 } while (need_seqretry(&peer->service_conn_lock, seq));
54 59
55 done_seqretry(&peer->service_conn_lock 60 done_seqretry(&peer->service_conn_lock, seq);
56 _leave(" = %d", conn ? conn->debug_id 61 _leave(" = %d", conn ? conn->debug_id : -1);
57 return conn; 62 return conn;
58 } 63 }
59 64
60 /* 65 /*
61 * Insert a service connection into a peer's t 66 * Insert a service connection into a peer's tree, thereby making it a target
62 * for incoming packets. 67 * for incoming packets.
63 */ 68 */
64 static void rxrpc_publish_service_conn(struct 69 static void rxrpc_publish_service_conn(struct rxrpc_peer *peer,
65 struct 70 struct rxrpc_connection *conn)
66 { 71 {
67 struct rxrpc_connection *cursor = NULL 72 struct rxrpc_connection *cursor = NULL;
68 struct rxrpc_conn_proto k = conn->prot 73 struct rxrpc_conn_proto k = conn->proto;
69 struct rb_node **pp, *parent; 74 struct rb_node **pp, *parent;
70 75
71 write_seqlock(&peer->service_conn_lock !! 76 write_seqlock_bh(&peer->service_conn_lock);
72 77
73 pp = &peer->service_conns.rb_node; 78 pp = &peer->service_conns.rb_node;
74 parent = NULL; 79 parent = NULL;
75 while (*pp) { 80 while (*pp) {
76 parent = *pp; 81 parent = *pp;
77 cursor = rb_entry(parent, 82 cursor = rb_entry(parent,
78 struct rxrpc 83 struct rxrpc_connection, service_node);
79 84
80 if (cursor->proto.index_key < 85 if (cursor->proto.index_key < k.index_key)
81 pp = &(*pp)->rb_left; 86 pp = &(*pp)->rb_left;
82 else if (cursor->proto.index_k 87 else if (cursor->proto.index_key > k.index_key)
83 pp = &(*pp)->rb_right; 88 pp = &(*pp)->rb_right;
84 else 89 else
85 goto found_extant_conn 90 goto found_extant_conn;
86 } 91 }
87 92
88 rb_link_node_rcu(&conn->service_node, 93 rb_link_node_rcu(&conn->service_node, parent, pp);
89 rb_insert_color(&conn->service_node, & 94 rb_insert_color(&conn->service_node, &peer->service_conns);
90 conn_published: 95 conn_published:
91 set_bit(RXRPC_CONN_IN_SERVICE_CONNS, & 96 set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags);
92 write_sequnlock(&peer->service_conn_lo !! 97 write_sequnlock_bh(&peer->service_conn_lock);
93 _leave(" = %d [new]", conn->debug_id); 98 _leave(" = %d [new]", conn->debug_id);
94 return; 99 return;
95 100
96 found_extant_conn: 101 found_extant_conn:
97 if (refcount_read(&cursor->ref) == 0) !! 102 if (atomic_read(&cursor->usage) == 0)
98 goto replace_old_connection; 103 goto replace_old_connection;
99 write_sequnlock(&peer->service_conn_lo !! 104 write_sequnlock_bh(&peer->service_conn_lock);
100 /* We should not be able to get here. 105 /* We should not be able to get here. rxrpc_incoming_connection() is
101 * called in a non-reentrant context, 106 * called in a non-reentrant context, so there can't be a race to
102 * insert a new connection. 107 * insert a new connection.
103 */ 108 */
104 BUG(); 109 BUG();
105 110
106 replace_old_connection: 111 replace_old_connection:
107 /* The old connection is from an outda 112 /* The old connection is from an outdated epoch. */
108 _debug("replace conn"); 113 _debug("replace conn");
109 rb_replace_node_rcu(&cursor->service_n 114 rb_replace_node_rcu(&cursor->service_node,
110 &conn->service_nod 115 &conn->service_node,
111 &peer->service_con 116 &peer->service_conns);
112 clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, 117 clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &cursor->flags);
113 goto conn_published; 118 goto conn_published;
114 } 119 }
115 120
116 /* 121 /*
117 * Preallocate a service connection. The conn 122 * Preallocate a service connection. The connection is placed on the proc and
118 * reap lists so that we don't have to get the 123 * reap lists so that we don't have to get the lock from BH context.
119 */ 124 */
120 struct rxrpc_connection *rxrpc_prealloc_servic 125 struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *rxnet,
121 126 gfp_t gfp)
122 { 127 {
123 struct rxrpc_connection *conn = rxrpc_ !! 128 struct rxrpc_connection *conn = rxrpc_alloc_connection(gfp);
124 129
125 if (conn) { 130 if (conn) {
126 /* We maintain an extra ref on 131 /* We maintain an extra ref on the connection whilst it is on
127 * the rxrpc_connections list. 132 * the rxrpc_connections list.
128 */ 133 */
129 conn->state = RXRPC_CONN_SERVI 134 conn->state = RXRPC_CONN_SERVICE_PREALLOC;
130 refcount_set(&conn->ref, 2); !! 135 atomic_set(&conn->usage, 2);
>> 136 conn->bundle = rxrpc_get_bundle(&rxrpc_service_dummy_bundle);
131 137
132 atomic_inc(&rxnet->nr_conns); 138 atomic_inc(&rxnet->nr_conns);
133 write_lock(&rxnet->conn_lock); 139 write_lock(&rxnet->conn_lock);
134 list_add_tail(&conn->link, &rx 140 list_add_tail(&conn->link, &rxnet->service_conns);
135 list_add_tail(&conn->proc_link 141 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
136 write_unlock(&rxnet->conn_lock 142 write_unlock(&rxnet->conn_lock);
137 143
138 rxrpc_see_connection(conn, rxr !! 144 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_service,
>> 145 atomic_read(&conn->usage),
>> 146 __builtin_return_address(0));
139 } 147 }
140 148
141 return conn; 149 return conn;
142 } 150 }
143 151
144 /* 152 /*
145 * Set up an incoming connection. This is cal 153 * Set up an incoming connection. This is called in BH context with the RCU
146 * read lock held. 154 * read lock held.
147 */ 155 */
148 void rxrpc_new_incoming_connection(struct rxrp 156 void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
149 struct rxrp 157 struct rxrpc_connection *conn,
150 const struc 158 const struct rxrpc_security *sec,
151 struct sk_b 159 struct sk_buff *skb)
152 { 160 {
153 struct rxrpc_skb_priv *sp = rxrpc_skb( 161 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
154 162
155 _enter(""); 163 _enter("");
156 164
157 conn->proto.epoch = sp->hdr.epoc 165 conn->proto.epoch = sp->hdr.epoch;
158 conn->proto.cid = sp->hdr.cid 166 conn->proto.cid = sp->hdr.cid & RXRPC_CIDMASK;
159 conn->orig_service_id = sp->hdr.serv !! 167 conn->params.service_id = sp->hdr.serviceId;
160 conn->service_id = sp->hdr.serv 168 conn->service_id = sp->hdr.serviceId;
161 conn->security_ix = sp->hdr.secu 169 conn->security_ix = sp->hdr.securityIndex;
162 conn->out_clientflag = 0; 170 conn->out_clientflag = 0;
163 conn->security = sec; 171 conn->security = sec;
164 if (conn->security_ix) 172 if (conn->security_ix)
165 conn->state = RXRPC_CONN_S 173 conn->state = RXRPC_CONN_SERVICE_UNSECURED;
166 else 174 else
167 conn->state = RXRPC_CONN_S 175 conn->state = RXRPC_CONN_SERVICE;
168 176
169 /* See if we should upgrade the servic 177 /* See if we should upgrade the service. This can only happen on the
170 * first packet on a new connection. 178 * first packet on a new connection. Once done, it applies to all
171 * subsequent calls on that connection 179 * subsequent calls on that connection.
172 */ 180 */
173 if (sp->hdr.userStatus == RXRPC_USERST 181 if (sp->hdr.userStatus == RXRPC_USERSTATUS_SERVICE_UPGRADE &&
174 conn->service_id == rx->service_up 182 conn->service_id == rx->service_upgrade.from)
175 conn->service_id = rx->service 183 conn->service_id = rx->service_upgrade.to;
176 184
177 atomic_set(&conn->active, 1); <<
178 <<
179 /* Make the connection a target for in 185 /* Make the connection a target for incoming packets. */
180 rxrpc_publish_service_conn(conn->peer, !! 186 rxrpc_publish_service_conn(conn->params.peer, conn);
>> 187
>> 188 _net("CONNECTION new %d {%x}", conn->debug_id, conn->proto.cid);
181 } 189 }
182 190
183 /* 191 /*
184 * Remove the service connection from the peer 192 * Remove the service connection from the peer's tree, thereby removing it as a
185 * target for incoming packets. 193 * target for incoming packets.
186 */ 194 */
187 void rxrpc_unpublish_service_conn(struct rxrpc 195 void rxrpc_unpublish_service_conn(struct rxrpc_connection *conn)
188 { 196 {
189 struct rxrpc_peer *peer = conn->peer; !! 197 struct rxrpc_peer *peer = conn->params.peer;
190 198
191 write_seqlock(&peer->service_conn_lock !! 199 write_seqlock_bh(&peer->service_conn_lock);
192 if (test_and_clear_bit(RXRPC_CONN_IN_S 200 if (test_and_clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags))
193 rb_erase(&conn->service_node, 201 rb_erase(&conn->service_node, &peer->service_conns);
194 write_sequnlock(&peer->service_conn_lo !! 202 write_sequnlock_bh(&peer->service_conn_lock);
195 } 203 }
196 204
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