1 // SPDX-License-Identifier: GPL-2.0-or-later 1
2 /* Service connection management
3 *
4 * Copyright (C) 2016 Red Hat, Inc. All Rights
5 * Written by David Howells (dhowells@redhat.c
6 */
7
8 #include <linux/slab.h>
9 #include "ar-internal.h"
10
11 /*
12 * Find a service connection under RCU conditi
13 *
14 * We could use a hash table, but that is subj
15 * attacker as the client gets to pick the epo
16 * the hash function. So, instead, we use a h
17 * that an rbtree to find the service connecti
18 * it might be slower than a large hash table,
19 * depth.
20 */
21 struct rxrpc_connection *rxrpc_find_service_co
22
23 {
24 struct rxrpc_connection *conn = NULL;
25 struct rxrpc_conn_proto k;
26 struct rxrpc_skb_priv *sp = rxrpc_skb(
27 struct rb_node *p;
28 unsigned int seq = 1;
29
30 k.epoch = sp->hdr.epoch;
31 k.cid = sp->hdr.cid & RXRPC_CIDMASK;
32
33 do {
34 /* Unfortunately, rbtree walki
35 * under just the RCU read loc
36 * changes.
37 */
38 seq++; /* 2 on the 1st/lockles
39 read_seqbegin_or_lock(&peer->s
40
41 p = rcu_dereference_raw(peer->
42 while (p) {
43 conn = rb_entry(p, str
44
45 if (conn->proto.index_
46 p = rcu_derefe
47 else if (conn->proto.i
48 p = rcu_derefe
49 else
50 break;
51 conn = NULL;
52 }
53 } while (need_seqretry(&peer->service_
54
55 done_seqretry(&peer->service_conn_lock
56 _leave(" = %d", conn ? conn->debug_id
57 return conn;
58 }
59
60 /*
61 * Insert a service connection into a peer's t
62 * for incoming packets.
63 */
64 static void rxrpc_publish_service_conn(struct
65 struct
66 {
67 struct rxrpc_connection *cursor = NULL
68 struct rxrpc_conn_proto k = conn->prot
69 struct rb_node **pp, *parent;
70
71 write_seqlock(&peer->service_conn_lock
72
73 pp = &peer->service_conns.rb_node;
74 parent = NULL;
75 while (*pp) {
76 parent = *pp;
77 cursor = rb_entry(parent,
78 struct rxrpc
79
80 if (cursor->proto.index_key <
81 pp = &(*pp)->rb_left;
82 else if (cursor->proto.index_k
83 pp = &(*pp)->rb_right;
84 else
85 goto found_extant_conn
86 }
87
88 rb_link_node_rcu(&conn->service_node,
89 rb_insert_color(&conn->service_node, &
90 conn_published:
91 set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &
92 write_sequnlock(&peer->service_conn_lo
93 _leave(" = %d [new]", conn->debug_id);
94 return;
95
96 found_extant_conn:
97 if (refcount_read(&cursor->ref) == 0)
98 goto replace_old_connection;
99 write_sequnlock(&peer->service_conn_lo
100 /* We should not be able to get here.
101 * called in a non-reentrant context,
102 * insert a new connection.
103 */
104 BUG();
105
106 replace_old_connection:
107 /* The old connection is from an outda
108 _debug("replace conn");
109 rb_replace_node_rcu(&cursor->service_n
110 &conn->service_nod
111 &peer->service_con
112 clear_bit(RXRPC_CONN_IN_SERVICE_CONNS,
113 goto conn_published;
114 }
115
116 /*
117 * Preallocate a service connection. The conn
118 * reap lists so that we don't have to get the
119 */
120 struct rxrpc_connection *rxrpc_prealloc_servic
121
122 {
123 struct rxrpc_connection *conn = rxrpc_
124
125 if (conn) {
126 /* We maintain an extra ref on
127 * the rxrpc_connections list.
128 */
129 conn->state = RXRPC_CONN_SERVI
130 refcount_set(&conn->ref, 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
138 rxrpc_see_connection(conn, rxr
139 }
140
141 return conn;
142 }
143
144 /*
145 * Set up an incoming connection. This is cal
146 * read lock held.
147 */
148 void rxrpc_new_incoming_connection(struct rxrp
149 struct rxrp
150 const struc
151 struct sk_b
152 {
153 struct rxrpc_skb_priv *sp = rxrpc_skb(
154
155 _enter("");
156
157 conn->proto.epoch = sp->hdr.epoc
158 conn->proto.cid = sp->hdr.cid
159 conn->orig_service_id = sp->hdr.serv
160 conn->service_id = sp->hdr.serv
161 conn->security_ix = sp->hdr.secu
162 conn->out_clientflag = 0;
163 conn->security = sec;
164 if (conn->security_ix)
165 conn->state = RXRPC_CONN_S
166 else
167 conn->state = RXRPC_CONN_S
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
180 rxrpc_publish_service_conn(conn->peer,
181 }
182
183 /*
184 * Remove the service connection from the peer
185 * target for incoming packets.
186 */
187 void rxrpc_unpublish_service_conn(struct rxrpc
188 {
189 struct rxrpc_peer *peer = conn->peer;
190
191 write_seqlock(&peer->service_conn_lock
192 if (test_and_clear_bit(RXRPC_CONN_IN_S
193 rb_erase(&conn->service_node,
194 write_sequnlock(&peer->service_conn_lo
195 }
196
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