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 .ref = REFCOUNT_INIT(1),
>> 13 .debug_id = UINT_MAX,
>> 14 };
>> 15
11 /* 16 /*
12 * Find a service connection under RCU conditi 17 * Find a service connection under RCU conditions.
13 * 18 *
14 * We could use a hash table, but that is subj 19 * 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 20 * 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 21 * the hash function. So, instead, we use a hash table for the peer and from
17 * that an rbtree to find the service connecti 22 * that an rbtree to find the service connection. Under ordinary circumstances
18 * it might be slower than a large hash table, 23 * it might be slower than a large hash table, but it is at least limited in
19 * depth. 24 * depth.
20 */ 25 */
21 struct rxrpc_connection *rxrpc_find_service_co 26 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer,
22 27 struct sk_buff *skb)
23 { 28 {
24 struct rxrpc_connection *conn = NULL; 29 struct rxrpc_connection *conn = NULL;
25 struct rxrpc_conn_proto k; 30 struct rxrpc_conn_proto k;
26 struct rxrpc_skb_priv *sp = rxrpc_skb( 31 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
27 struct rb_node *p; 32 struct rb_node *p;
28 unsigned int seq = 1; !! 33 unsigned int seq = 0;
29 34
30 k.epoch = sp->hdr.epoch; 35 k.epoch = sp->hdr.epoch;
31 k.cid = sp->hdr.cid & RXRPC_CIDMASK; 36 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
32 37
33 do { 38 do {
34 /* Unfortunately, rbtree walki 39 /* Unfortunately, rbtree walking doesn't give reliable results
35 * under just the RCU read loc 40 * under just the RCU read lock, so we have to check for
36 * changes. 41 * changes.
37 */ 42 */
38 seq++; /* 2 on the 1st/lockles <<
39 read_seqbegin_or_lock(&peer->s 43 read_seqbegin_or_lock(&peer->service_conn_lock, &seq);
40 44
41 p = rcu_dereference_raw(peer-> 45 p = rcu_dereference_raw(peer->service_conns.rb_node);
42 while (p) { 46 while (p) {
43 conn = rb_entry(p, str 47 conn = rb_entry(p, struct rxrpc_connection, service_node);
44 48
45 if (conn->proto.index_ 49 if (conn->proto.index_key < k.index_key)
46 p = rcu_derefe 50 p = rcu_dereference_raw(p->rb_left);
47 else if (conn->proto.i 51 else if (conn->proto.index_key > k.index_key)
48 p = rcu_derefe 52 p = rcu_dereference_raw(p->rb_right);
49 else 53 else
50 break; 54 break;
51 conn = NULL; 55 conn = NULL;
52 } 56 }
53 } while (need_seqretry(&peer->service_ 57 } while (need_seqretry(&peer->service_conn_lock, seq));
54 58
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(&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(&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 (refcount_read(&cursor->ref) == 0)
98 goto replace_old_connection; 102 goto replace_old_connection;
99 write_sequnlock(&peer->service_conn_lo 103 write_sequnlock(&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(struct rxrpc_net *rxnet,
121 125 gfp_t gfp)
122 { 126 {
123 struct rxrpc_connection *conn = rxrpc_ 127 struct rxrpc_connection *conn = rxrpc_alloc_connection(rxnet, gfp);
124 128
125 if (conn) { 129 if (conn) {
126 /* We maintain an extra ref on 130 /* We maintain an extra ref on the connection whilst it is on
127 * the rxrpc_connections list. 131 * the rxrpc_connections list.
128 */ 132 */
129 conn->state = RXRPC_CONN_SERVI 133 conn->state = RXRPC_CONN_SERVICE_PREALLOC;
130 refcount_set(&conn->ref, 2); 134 refcount_set(&conn->ref, 2);
>> 135 conn->bundle = rxrpc_get_bundle(&rxrpc_service_dummy_bundle,
>> 136 rxrpc_bundle_get_service_conn);
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 rxrpc_see_connection(conn, rxrpc_conn_new_service);
139 } 145 }
140 146
141 return conn; 147 return conn;
142 } 148 }
143 149
144 /* 150 /*
145 * Set up an incoming connection. This is cal 151 * Set up an incoming connection. This is called in BH context with the RCU
146 * read lock held. 152 * read lock held.
147 */ 153 */
148 void rxrpc_new_incoming_connection(struct rxrp 154 void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
149 struct rxrp 155 struct rxrpc_connection *conn,
150 const struc 156 const struct rxrpc_security *sec,
151 struct sk_b 157 struct sk_buff *skb)
152 { 158 {
153 struct rxrpc_skb_priv *sp = rxrpc_skb( 159 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
154 160
155 _enter(""); 161 _enter("");
156 162
157 conn->proto.epoch = sp->hdr.epoc 163 conn->proto.epoch = sp->hdr.epoch;
158 conn->proto.cid = sp->hdr.cid 164 conn->proto.cid = sp->hdr.cid & RXRPC_CIDMASK;
159 conn->orig_service_id = sp->hdr.serv 165 conn->orig_service_id = sp->hdr.serviceId;
160 conn->service_id = sp->hdr.serv 166 conn->service_id = sp->hdr.serviceId;
161 conn->security_ix = sp->hdr.secu 167 conn->security_ix = sp->hdr.securityIndex;
162 conn->out_clientflag = 0; 168 conn->out_clientflag = 0;
163 conn->security = sec; 169 conn->security = sec;
164 if (conn->security_ix) 170 if (conn->security_ix)
165 conn->state = RXRPC_CONN_S 171 conn->state = RXRPC_CONN_SERVICE_UNSECURED;
166 else 172 else
167 conn->state = RXRPC_CONN_S 173 conn->state = RXRPC_CONN_SERVICE;
168 174
169 /* See if we should upgrade the servic 175 /* See if we should upgrade the service. This can only happen on the
170 * first packet on a new connection. 176 * first packet on a new connection. Once done, it applies to all
171 * subsequent calls on that connection 177 * subsequent calls on that connection.
172 */ 178 */
173 if (sp->hdr.userStatus == RXRPC_USERST 179 if (sp->hdr.userStatus == RXRPC_USERSTATUS_SERVICE_UPGRADE &&
174 conn->service_id == rx->service_up 180 conn->service_id == rx->service_upgrade.from)
175 conn->service_id = rx->service 181 conn->service_id = rx->service_upgrade.to;
176 182
177 atomic_set(&conn->active, 1); 183 atomic_set(&conn->active, 1);
178 184
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->peer, conn);
181 } 187 }
182 188
183 /* 189 /*
184 * Remove the service connection from the peer 190 * Remove the service connection from the peer's tree, thereby removing it as a
185 * target for incoming packets. 191 * target for incoming packets.
186 */ 192 */
187 void rxrpc_unpublish_service_conn(struct rxrpc 193 void rxrpc_unpublish_service_conn(struct rxrpc_connection *conn)
188 { 194 {
189 struct rxrpc_peer *peer = conn->peer; 195 struct rxrpc_peer *peer = conn->peer;
190 196
191 write_seqlock(&peer->service_conn_lock 197 write_seqlock(&peer->service_conn_lock);
192 if (test_and_clear_bit(RXRPC_CONN_IN_S 198 if (test_and_clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags))
193 rb_erase(&conn->service_node, 199 rb_erase(&conn->service_node, &peer->service_conns);
194 write_sequnlock(&peer->service_conn_lo 200 write_sequnlock(&peer->service_conn_lock);
195 } 201 }
196 202
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