*/
#include <linux/atomic.h>
+#include <linux/seqlock.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <rxrpc/packet.h>
struct hlist_head error_targets; /* targets for net error distribution */
struct work_struct error_distributor;
struct rb_root service_conns; /* Service connections */
- rwlock_t conn_lock;
+ seqlock_t service_conn_lock;
spinlock_t lock; /* access lock */
unsigned int if_mtu; /* interface MTU for this peer */
unsigned int mtu; /* network MTU for this peer */
extern struct list_head rxrpc_connections;
extern rwlock_t rxrpc_connection_lock;
-void rxrpc_conn_hash_proto_key(struct rxrpc_conn_proto *);
-void rxrpc_extract_conn_params(struct rxrpc_conn_proto *,
- struct rxrpc_local *, struct sk_buff *);
+int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *, struct sk_buff *);
struct rxrpc_connection *rxrpc_alloc_connection(gfp_t);
-struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_local *,
- struct sk_buff *);
+struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *,
+ struct sk_buff *);
void __rxrpc_disconnect_call(struct rxrpc_call *);
void rxrpc_disconnect_call(struct rxrpc_call *);
void rxrpc_put_connection(struct rxrpc_connection *);
return atomic_inc_not_zero(&conn->usage) ? conn : NULL;
}
-static inline void rxrpc_queue_conn(struct rxrpc_connection *conn)
+static inline bool rxrpc_queue_conn(struct rxrpc_connection *conn)
{
- if (rxrpc_get_connection_maybe(conn) &&
- !rxrpc_queue_work(&conn->processor))
+ if (!rxrpc_get_connection_maybe(conn))
+ return false;
+ if (!rxrpc_queue_work(&conn->processor))
rxrpc_put_connection(conn);
+ return true;
}
/*
* conn_service.c
*/
+struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
+ struct sk_buff *);
struct rxrpc_connection *rxrpc_incoming_connection(struct rxrpc_local *,
struct sockaddr_rxrpc *,
struct sk_buff *);
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/skbuff.h>
-#include <linux/crypto.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
}
/*
- * find a connection based on transport and RxRPC connection ID for an incoming
- * packet
+ * Look up a connection in the cache by protocol parameters.
+ *
+ * If successful, a pointer to the connection is returned, but no ref is taken.
+ * NULL is returned if there is no match.
+ *
+ * The caller must be holding the RCU read lock.
*/
-struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_local *local,
- struct sk_buff *skb)
+struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
+ struct sk_buff *skb)
{
struct rxrpc_connection *conn;
struct rxrpc_conn_proto k;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct sockaddr_rxrpc srx;
struct rxrpc_peer *peer;
- struct rb_node *p;
- _enter(",{%x,%x}", sp->hdr.cid, sp->hdr.flags);
+ _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
goto not_found;
+ k.epoch = sp->hdr.epoch;
+ k.cid = sp->hdr.cid & RXRPC_CIDMASK;
+
/* We may have to handle mixing IPv4 and IPv6 */
if (srx.transport.family != local->srx.transport.family) {
pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
peer = rxrpc_lookup_peer_rcu(local, &srx);
if (!peer)
goto not_found;
-
- read_lock_bh(&peer->conn_lock);
-
- p = peer->service_conns.rb_node;
- while (p) {
- conn = rb_entry(p, struct rxrpc_connection, service_node);
-
- _debug("maybe %x", conn->proto.cid);
-
- if (k.epoch < conn->proto.epoch)
- p = p->rb_left;
- else if (k.epoch > conn->proto.epoch)
- p = p->rb_right;
- else if (k.cid < conn->proto.cid)
- p = p->rb_left;
- else if (k.cid > conn->proto.cid)
- p = p->rb_right;
- else
- goto found_service_conn;
- }
- read_unlock_bh(&peer->conn_lock);
+ conn = rxrpc_find_service_conn_rcu(peer, skb);
+ if (!conn || atomic_read(&conn->usage) == 0)
+ goto not_found;
+ _leave(" = %p", conn);
+ return conn;
} else {
+ /* Look up client connections by connection ID alone as their
+ * IDs are unique for this machine.
+ */
conn = idr_find(&rxrpc_client_conn_ids,
- k.cid >> RXRPC_CIDSHIFT);
- if (!conn ||
- conn->proto.epoch != k.epoch ||
+ sp->hdr.cid >> RXRPC_CIDSHIFT);
+ if (!conn || atomic_read(&conn->usage) == 0) {
+ _debug("no conn");
+ goto not_found;
+ }
+
+ if (conn->proto.epoch != k.epoch ||
conn->params.local != local)
goto not_found;
BUG();
}
- conn = rxrpc_get_connection_maybe(conn);
_leave(" = %p", conn);
return conn;
}
not_found:
_leave(" = NULL");
return NULL;
-
-found_service_conn:
- conn = rxrpc_get_connection_maybe(conn);
- read_unlock_bh(&peer->conn_lock);
- _leave(" = %p", conn);
- return conn;
}
/*
#include <linux/slab.h>
#include "ar-internal.h"
+/*
+ * Find a service connection under RCU conditions.
+ *
+ * We could use a hash table, but that is subject to bucket stuffing by an
+ * attacker as the client gets to pick the epoch and cid values and would know
+ * the hash function. So, instead, we use a hash table for the peer and from
+ * that an rbtree to find the service connection. Under ordinary circumstances
+ * it might be slower than a large hash table, but it is at least limited in
+ * depth.
+ */
+struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer,
+ struct sk_buff *skb)
+{
+ struct rxrpc_connection *conn = NULL;
+ struct rxrpc_conn_proto k;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ struct rb_node *p;
+ unsigned int seq = 0;
+
+ k.epoch = sp->hdr.epoch;
+ k.cid = sp->hdr.cid & RXRPC_CIDMASK;
+
+ do {
+ /* Unfortunately, rbtree walking doesn't give reliable results
+ * under just the RCU read lock, so we have to check for
+ * changes.
+ */
+ read_seqbegin_or_lock(&peer->service_conn_lock, &seq);
+
+ p = rcu_dereference_raw(peer->service_conns.rb_node);
+ while (p) {
+ conn = rb_entry(p, struct rxrpc_connection, service_node);
+
+ if (conn->proto.index_key < k.index_key)
+ p = rcu_dereference_raw(p->rb_left);
+ else if (conn->proto.index_key > k.index_key)
+ p = rcu_dereference_raw(p->rb_right);
+ else
+ goto done;
+ conn = NULL;
+ }
+ } while (need_seqretry(&peer->service_conn_lock, seq));
+
+done:
+ done_seqretry(&peer->service_conn_lock, seq);
+ _leave(" = %d", conn ? conn->debug_id : -1);
+ return conn;
+}
+
+/*
+ * Insert a service connection into a peer's tree, thereby making it a target
+ * for incoming packets.
+ */
+static struct rxrpc_connection *
+rxrpc_publish_service_conn(struct rxrpc_peer *peer,
+ struct rxrpc_connection *conn)
+{
+ struct rxrpc_connection *cursor = NULL;
+ struct rxrpc_conn_proto k = conn->proto;
+ struct rb_node **pp, *parent;
+
+ write_seqlock_bh(&peer->service_conn_lock);
+
+ pp = &peer->service_conns.rb_node;
+ parent = NULL;
+ while (*pp) {
+ parent = *pp;
+ cursor = rb_entry(parent,
+ struct rxrpc_connection, service_node);
+
+ if (cursor->proto.index_key < k.index_key)
+ pp = &(*pp)->rb_left;
+ else if (cursor->proto.index_key > k.index_key)
+ pp = &(*pp)->rb_right;
+ else
+ goto found_extant_conn;
+ }
+
+ rb_link_node_rcu(&conn->service_node, parent, pp);
+ rb_insert_color(&conn->service_node, &peer->service_conns);
+conn_published:
+ set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags);
+ write_sequnlock_bh(&peer->service_conn_lock);
+ _leave(" = %d [new]", conn->debug_id);
+ return conn;
+
+found_extant_conn:
+ if (atomic_read(&cursor->usage) == 0)
+ goto replace_old_connection;
+ write_sequnlock_bh(&peer->service_conn_lock);
+ /* We should not be able to get here. rxrpc_incoming_connection() is
+ * called in a non-reentrant context, so there can't be a race to
+ * insert a new connection.
+ */
+ BUG();
+
+replace_old_connection:
+ /* The old connection is from an outdated epoch. */
+ _debug("replace conn");
+ rb_replace_node_rcu(&cursor->service_node,
+ &conn->service_node,
+ &peer->service_conns);
+ clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &cursor->flags);
+ goto conn_published;
+}
+
/*
* get a record of an incoming connection
*/
struct sockaddr_rxrpc *srx,
struct sk_buff *skb)
{
- struct rxrpc_connection *conn, *candidate = NULL;
+ struct rxrpc_connection *conn;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct rxrpc_peer *peer;
- struct rb_node *p, **pp;
const char *new = "old";
- u32 epoch, cid;
_enter("");
ASSERT(sp->hdr.flags & RXRPC_CLIENT_INITIATED);
- epoch = sp->hdr.epoch;
- cid = sp->hdr.cid & RXRPC_CIDMASK;
-
- /* search the connection list first */
- read_lock_bh(&peer->conn_lock);
-
- p = peer->service_conns.rb_node;
- while (p) {
- conn = rb_entry(p, struct rxrpc_connection, service_node);
-
- _debug("maybe %x", conn->proto.cid);
-
- if (epoch < conn->proto.epoch)
- p = p->rb_left;
- else if (epoch > conn->proto.epoch)
- p = p->rb_right;
- else if (cid < conn->proto.cid)
- p = p->rb_left;
- else if (cid > conn->proto.cid)
- p = p->rb_right;
- else
- goto found_extant_connection;
+ rcu_read_lock();
+ peer = rxrpc_lookup_peer_rcu(local, srx);
+ if (peer) {
+ conn = rxrpc_find_service_conn_rcu(peer, skb);
+ if (conn) {
+ if (sp->hdr.securityIndex != conn->security_ix)
+ goto security_mismatch_rcu;
+ if (rxrpc_get_connection_maybe(conn))
+ goto found_extant_connection_rcu;
+
+ /* The conn has expired but we can't remove it without
+ * the appropriate lock, so we attempt to replace it
+ * when we have a new candidate.
+ */
+ }
+
+ if (!rxrpc_get_peer_maybe(peer))
+ peer = NULL;
}
- read_unlock_bh(&peer->conn_lock);
-
- /* not yet present - create a candidate for a new record and then
- * redo the search */
- candidate = rxrpc_alloc_connection(GFP_NOIO);
- if (!candidate) {
- rxrpc_put_peer(peer);
- _leave(" = -ENOMEM");
- return ERR_PTR(-ENOMEM);
- }
-
- candidate->proto.epoch = sp->hdr.epoch;
- candidate->proto.cid = sp->hdr.cid & RXRPC_CIDMASK;
- candidate->params.local = local;
- candidate->params.peer = peer;
- candidate->params.service_id = sp->hdr.serviceId;
- candidate->security_ix = sp->hdr.securityIndex;
- candidate->out_clientflag = 0;
- candidate->state = RXRPC_CONN_SERVICE;
- if (candidate->params.service_id)
- candidate->state = RXRPC_CONN_SERVICE_UNSECURED;
-
- write_lock_bh(&peer->conn_lock);
-
- pp = &peer->service_conns.rb_node;
- p = NULL;
- while (*pp) {
- p = *pp;
- conn = rb_entry(p, struct rxrpc_connection, service_node);
+ rcu_read_unlock();
- if (epoch < conn->proto.epoch)
- pp = &(*pp)->rb_left;
- else if (epoch > conn->proto.epoch)
- pp = &(*pp)->rb_right;
- else if (cid < conn->proto.cid)
- pp = &(*pp)->rb_left;
- else if (cid > conn->proto.cid)
- pp = &(*pp)->rb_right;
- else
- goto found_extant_second;
+ if (!peer) {
+ peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
+ if (IS_ERR(peer))
+ goto enomem;
}
- /* we can now add the new candidate to the list */
- set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &candidate->flags);
- rb_link_node(&candidate->service_node, p, pp);
- rb_insert_color(&candidate->service_node, &peer->service_conns);
-attached:
- conn = candidate;
- candidate = NULL;
- rxrpc_get_peer(peer);
- rxrpc_get_local(local);
+ /* We don't have a matching record yet. */
+ conn = rxrpc_alloc_connection(GFP_NOIO);
+ if (!conn)
+ goto enomem_peer;
+
+ conn->proto.epoch = sp->hdr.epoch;
+ conn->proto.cid = sp->hdr.cid & RXRPC_CIDMASK;
+ conn->params.local = local;
+ conn->params.peer = peer;
+ conn->params.service_id = sp->hdr.serviceId;
+ conn->security_ix = sp->hdr.securityIndex;
+ conn->out_clientflag = 0;
+ conn->state = RXRPC_CONN_SERVICE;
+ if (conn->params.service_id)
+ conn->state = RXRPC_CONN_SERVICE_UNSECURED;
- write_unlock_bh(&peer->conn_lock);
+ rxrpc_get_local(local);
write_lock(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock(&rxrpc_connection_lock);
+ /* Make the connection a target for incoming packets. */
+ rxrpc_publish_service_conn(peer, conn);
+
new = "new";
success:
_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->proto.cid);
-
- rxrpc_put_peer(peer);
_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
return conn;
- /* we found the connection in the list immediately */
-found_extant_connection:
- if (!rxrpc_get_connection_maybe(conn)) {
- set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &candidate->flags);
- rb_replace_node(&conn->service_node,
- &candidate->service_node,
- &peer->service_conns);
- clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags);
- goto attached;
- }
-
- if (sp->hdr.securityIndex != conn->security_ix) {
- read_unlock_bh(&peer->conn_lock);
- goto security_mismatch_put;
- }
- read_unlock_bh(&peer->conn_lock);
- goto success;
-
- /* we found the connection on the second time through the list */
-found_extant_second:
- if (sp->hdr.securityIndex != conn->security_ix) {
- write_unlock_bh(&peer->conn_lock);
- goto security_mismatch;
- }
- rxrpc_get_connection(conn);
- write_unlock_bh(&peer->conn_lock);
- kfree(candidate);
+found_extant_connection_rcu:
+ rcu_read_unlock();
goto success;
-security_mismatch_put:
- rxrpc_put_connection(conn);
-security_mismatch:
- kfree(candidate);
+security_mismatch_rcu:
+ rcu_read_unlock();
_leave(" = -EKEYREJECTED");
return ERR_PTR(-EKEYREJECTED);
+
+enomem_peer:
+ rxrpc_put_peer(peer);
+enomem:
+ _leave(" = -ENOMEM");
+ return ERR_PTR(-ENOMEM);
}
/*
{
struct rxrpc_peer *peer = conn->params.peer;
- write_lock_bh(&peer->conn_lock);
+ write_seqlock_bh(&peer->service_conn_lock);
if (test_and_clear_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags))
rb_erase(&conn->service_node, &peer->service_conns);
- write_unlock_bh(&peer->conn_lock);
+ write_sequnlock_bh(&peer->service_conn_lock);
}
* post connection-level events to the connection
* - this includes challenges, responses and some aborts
*/
-static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
+static bool rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
struct sk_buff *skb)
{
_enter("%p,%p", conn, skb);
skb_queue_tail(&conn->rx_queue, skb);
- rxrpc_queue_conn(conn);
+ return rxrpc_queue_conn(conn);
}
/*
*/
void rxrpc_data_ready(struct sock *sk)
{
+ struct rxrpc_connection *conn;
struct rxrpc_skb_priv *sp;
struct rxrpc_local *local = sk->sk_user_data;
struct sk_buff *skb;
(sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
goto bad_message;
- if (sp->hdr.callNumber == 0) {
- /* This is a connection-level packet. These should be
- * fairly rare, so the extra overhead of looking them up the
- * old-fashioned way doesn't really hurt */
- struct rxrpc_connection *conn;
-
- rcu_read_lock();
- conn = rxrpc_find_connection(local, skb);
- rcu_read_unlock();
- if (!conn)
- goto cant_route_call;
+ rcu_read_lock();
+
+retry_find_conn:
+ conn = rxrpc_find_connection_rcu(local, skb);
+ if (!conn)
+ goto cant_route_call;
+ if (sp->hdr.callNumber == 0) {
+ /* Connection-level packet */
_debug("CONN %p {%d}", conn, conn->debug_id);
- rxrpc_post_packet_to_conn(conn, skb);
- rxrpc_put_connection(conn);
+ if (!rxrpc_post_packet_to_conn(conn, skb))
+ goto retry_find_conn;
} else {
- struct rxrpc_call *call;
+ /* Call-bound packets are routed by connection channel. */
+ unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
+ struct rxrpc_channel *chan = &conn->channels[channel];
+ struct rxrpc_call *call = rcu_dereference(chan->call);
- call = rxrpc_find_call_hash(&sp->hdr, local,
- AF_INET, &ip_hdr(skb)->saddr);
- if (call)
- rxrpc_post_packet_to_call(call, skb);
- else
+ if (!call || atomic_read(&call->usage) == 0)
goto cant_route_call;
+
+ rxrpc_post_packet_to_call(call, skb);
}
+ rcu_read_unlock();
out:
return;
cant_route_call:
+ rcu_read_unlock();
+
_debug("can't route call");
if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
projects / users / willy / pagecache.git / commitdiff