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linux/net/rxrpc/ar-connection.c
David Howells 651350d10f [AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use 
Add an interface to the AF_RXRPC module so that the AFS filesystem module can
more easily make use of the services available.  AFS still opens a socket but
then uses the action functions in lieu of sendmsg() and registers an intercept
functions to grab messages before they're queued on the socket Rx queue.

This permits AFS (or whatever) to:

 (1) Avoid the overhead of using the recvmsg() call.

 (2) Use different keys directly on individual client calls on one socket
     rather than having to open a whole slew of sockets, one for each key it
     might want to use.

 (3) Avoid calling request_key() at the point of issue of a call or opening of
     a socket.  This is done instead by AFS at the point of open(), unlink() or
     other VFS operation and the key handed through.

 (4) Request the use of something other than GFP_KERNEL to allocate memory.

Furthermore:

 (*) The socket buffer markings used by RxRPC are made available for AFS so
     that it can interpret the cooked RxRPC messages itself.

 (*) rxgen (un)marshalling abort codes are made available.


The following documentation for the kernel interface is added to
Documentation/networking/rxrpc.txt:

=========================
AF_RXRPC KERNEL INTERFACE
=========================

The AF_RXRPC module also provides an interface for use by in-kernel utilities
such as the AFS filesystem.  This permits such a utility to:

 (1) Use different keys directly on individual client calls on one socket
     rather than having to open a whole slew of sockets, one for each key it
     might want to use.

 (2) Avoid having RxRPC call request_key() at the point of issue of a call or
     opening of a socket.  Instead the utility is responsible for requesting a
     key at the appropriate point.  AFS, for instance, would do this during VFS
     operations such as open() or unlink().  The key is then handed through
     when the call is initiated.

 (3) Request the use of something other than GFP_KERNEL to allocate memory.

 (4) Avoid the overhead of using the recvmsg() call.  RxRPC messages can be
     intercepted before they get put into the socket Rx queue and the socket
     buffers manipulated directly.

To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
bind an addess as appropriate and listen if it's to be a server socket, but
then it passes this to the kernel interface functions.

The kernel interface functions are as follows:

 (*) Begin a new client call.

	struct rxrpc_call *
	rxrpc_kernel_begin_call(struct socket *sock,
				struct sockaddr_rxrpc *srx,
				struct key *key,
				unsigned long user_call_ID,
				gfp_t gfp);

     This allocates the infrastructure to make a new RxRPC call and assigns
     call and connection numbers.  The call will be made on the UDP port that
     the socket is bound to.  The call will go to the destination address of a
     connected client socket unless an alternative is supplied (srx is
     non-NULL).

     If a key is supplied then this will be used to secure the call instead of
     the key bound to the socket with the RXRPC_SECURITY_KEY sockopt.  Calls
     secured in this way will still share connections if at all possible.

     The user_call_ID is equivalent to that supplied to sendmsg() in the
     control data buffer.  It is entirely feasible to use this to point to a
     kernel data structure.

     If this function is successful, an opaque reference to the RxRPC call is
     returned.  The caller now holds a reference on this and it must be
     properly ended.

 (*) End a client call.

	void rxrpc_kernel_end_call(struct rxrpc_call *call);

     This is used to end a previously begun call.  The user_call_ID is expunged
     from AF_RXRPC's knowledge and will not be seen again in association with
     the specified call.

 (*) Send data through a call.

	int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
				   size_t len);

     This is used to supply either the request part of a client call or the
     reply part of a server call.  msg.msg_iovlen and msg.msg_iov specify the
     data buffers to be used.  msg_iov may not be NULL and must point
     exclusively to in-kernel virtual addresses.  msg.msg_flags may be given
     MSG_MORE if there will be subsequent data sends for this call.

     The msg must not specify a destination address, control data or any flags
     other than MSG_MORE.  len is the total amount of data to transmit.

 (*) Abort a call.

	void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);

     This is used to abort a call if it's still in an abortable state.  The
     abort code specified will be placed in the ABORT message sent.

 (*) Intercept received RxRPC messages.

	typedef void (*rxrpc_interceptor_t)(struct sock *sk,
					    unsigned long user_call_ID,
					    struct sk_buff *skb);

	void
	rxrpc_kernel_intercept_rx_messages(struct socket *sock,
					   rxrpc_interceptor_t interceptor);

     This installs an interceptor function on the specified AF_RXRPC socket.
     All messages that would otherwise wind up in the socket's Rx queue are
     then diverted to this function.  Note that care must be taken to process
     the messages in the right order to maintain DATA message sequentiality.

     The interceptor function itself is provided with the address of the socket
     and handling the incoming message, the ID assigned by the kernel utility
     to the call and the socket buffer containing the message.

     The skb->mark field indicates the type of message:

	MARK				MEANING
	===============================	=======================================
	RXRPC_SKB_MARK_DATA		Data message
	RXRPC_SKB_MARK_FINAL_ACK	Final ACK received for an incoming call
	RXRPC_SKB_MARK_BUSY		Client call rejected as server busy
	RXRPC_SKB_MARK_REMOTE_ABORT	Call aborted by peer
	RXRPC_SKB_MARK_NET_ERROR	Network error detected
	RXRPC_SKB_MARK_LOCAL_ERROR	Local error encountered
	RXRPC_SKB_MARK_NEW_CALL		New incoming call awaiting acceptance

     The remote abort message can be probed with rxrpc_kernel_get_abort_code().
     The two error messages can be probed with rxrpc_kernel_get_error_number().
     A new call can be accepted with rxrpc_kernel_accept_call().

     Data messages can have their contents extracted with the usual bunch of
     socket buffer manipulation functions.  A data message can be determined to
     be the last one in a sequence with rxrpc_kernel_is_data_last().  When a
     data message has been used up, rxrpc_kernel_data_delivered() should be
     called on it..

     Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
     of.  It is possible to get extra refs on all types of message for later
     freeing, but this may pin the state of a call until the message is finally
     freed.

 (*) Accept an incoming call.

	struct rxrpc_call *
	rxrpc_kernel_accept_call(struct socket *sock,
				 unsigned long user_call_ID);

     This is used to accept an incoming call and to assign it a call ID.  This
     function is similar to rxrpc_kernel_begin_call() and calls accepted must
     be ended in the same way.

     If this function is successful, an opaque reference to the RxRPC call is
     returned.  The caller now holds a reference on this and it must be
     properly ended.

 (*) Reject an incoming call.

	int rxrpc_kernel_reject_call(struct socket *sock);

     This is used to reject the first incoming call on the socket's queue with
     a BUSY message.  -ENODATA is returned if there were no incoming calls.
     Other errors may be returned if the call had been aborted (-ECONNABORTED)
     or had timed out (-ETIME).

 (*) Record the delivery of a data message and free it.

	void rxrpc_kernel_data_delivered(struct sk_buff *skb);

     This is used to record a data message as having been delivered and to
     update the ACK state for the call.  The socket buffer will be freed.

 (*) Free a message.

	void rxrpc_kernel_free_skb(struct sk_buff *skb);

     This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
     socket.

 (*) Determine if a data message is the last one on a call.

	bool rxrpc_kernel_is_data_last(struct sk_buff *skb);

     This is used to determine if a socket buffer holds the last data message
     to be received for a call (true will be returned if it does, false
     if not).

     The data message will be part of the reply on a client call and the
     request on an incoming call.  In the latter case there will be more
     messages, but in the former case there will not.

 (*) Get the abort code from an abort message.

	u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);

     This is used to extract the abort code from a remote abort message.

 (*) Get the error number from a local or network error message.

	int rxrpc_kernel_get_error_number(struct sk_buff *skb);

     This is used to extract the error number from a message indicating either
     a local error occurred or a network error occurred.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-26 15:50:17 -07:00

912 lines
23 KiB
C
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/* RxRPC virtual connection handler
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.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"
static void rxrpc_connection_reaper(struct work_struct *work);
LIST_HEAD(rxrpc_connections);
DEFINE_RWLOCK(rxrpc_connection_lock);
static unsigned long rxrpc_connection_timeout = 10 * 60;
static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
/*
* allocate a new client connection bundle
*/
static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
{
struct rxrpc_conn_bundle *bundle;
_enter("");
bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
if (bundle) {
INIT_LIST_HEAD(&bundle->unused_conns);
INIT_LIST_HEAD(&bundle->avail_conns);
INIT_LIST_HEAD(&bundle->busy_conns);
init_waitqueue_head(&bundle->chanwait);
atomic_set(&bundle->usage, 1);
}
_leave(" = %p", bundle);
return bundle;
}
/*
* compare bundle parameters with what we're looking for
* - return -ve, 0 or +ve
*/
static inline
int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
struct key *key, __be16 service_id)
{
return (bundle->service_id - service_id) ?:
((unsigned long) bundle->key - (unsigned long) key);
}
/*
* get bundle of client connections that a client socket can make use of
*/
struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
struct key *key,
__be16 service_id,
gfp_t gfp)
{
struct rxrpc_conn_bundle *bundle, *candidate;
struct rb_node *p, *parent, **pp;
_enter("%p{%x},%x,%hx,",
rx, key_serial(key), trans->debug_id, ntohl(service_id));
if (rx->trans == trans && rx->bundle) {
atomic_inc(&rx->bundle->usage);
return rx->bundle;
}
/* search the extant bundles first for one that matches the specified
* user ID */
spin_lock(&trans->client_lock);
p = trans->bundles.rb_node;
while (p) {
bundle = rb_entry(p, struct rxrpc_conn_bundle, node);
if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
p = p->rb_left;
else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
p = p->rb_right;
else
goto found_extant_bundle;
}
spin_unlock(&trans->client_lock);
/* not yet present - create a candidate for a new record and then
* redo the search */
candidate = rxrpc_alloc_bundle(gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
candidate->key = key_get(key);
candidate->service_id = service_id;
spin_lock(&trans->client_lock);
pp = &trans->bundles.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);
if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
pp = &(*pp)->rb_left;
else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
pp = &(*pp)->rb_right;
else
goto found_extant_second;
}
/* second search also failed; add the new bundle */
bundle = candidate;
candidate = NULL;
rb_link_node(&bundle->node, parent, pp);
rb_insert_color(&bundle->node, &trans->bundles);
spin_unlock(&trans->client_lock);
_net("BUNDLE new on trans %d", trans->debug_id);
if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
atomic_inc(&bundle->usage);
rx->bundle = bundle;
}
_leave(" = %p [new]", bundle);
return bundle;
/* we found the bundle in the list immediately */
found_extant_bundle:
atomic_inc(&bundle->usage);
spin_unlock(&trans->client_lock);
_net("BUNDLE old on trans %d", trans->debug_id);
if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
atomic_inc(&bundle->usage);
rx->bundle = bundle;
}
_leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
return bundle;
/* we found the bundle on the second time through the list */
found_extant_second:
atomic_inc(&bundle->usage);
spin_unlock(&trans->client_lock);
kfree(candidate);
_net("BUNDLE old2 on trans %d", trans->debug_id);
if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
atomic_inc(&bundle->usage);
rx->bundle = bundle;
}
_leave(" = %p [second %d]", bundle, atomic_read(&bundle->usage));
return bundle;
}
/*
* release a bundle
*/
void rxrpc_put_bundle(struct rxrpc_transport *trans,
struct rxrpc_conn_bundle *bundle)
{
_enter("%p,%p{%d}",trans, bundle, atomic_read(&bundle->usage));
if (atomic_dec_and_lock(&bundle->usage, &trans->client_lock)) {
_debug("Destroy bundle");
rb_erase(&bundle->node, &trans->bundles);
spin_unlock(&trans->client_lock);
ASSERT(list_empty(&bundle->unused_conns));
ASSERT(list_empty(&bundle->avail_conns));
ASSERT(list_empty(&bundle->busy_conns));
ASSERTCMP(bundle->num_conns, ==, 0);
key_put(bundle->key);
kfree(bundle);
}
_leave("");
}
/*
* allocate a new connection
*/
static struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
{
struct rxrpc_connection *conn;
_enter("");
conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
if (conn) {
INIT_WORK(&conn->processor, &rxrpc_process_connection);
INIT_LIST_HEAD(&conn->bundle_link);
conn->calls = RB_ROOT;
skb_queue_head_init(&conn->rx_queue);
rwlock_init(&conn->lock);
spin_lock_init(&conn->state_lock);
atomic_set(&conn->usage, 1);
conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
conn->avail_calls = RXRPC_MAXCALLS;
conn->size_align = 4;
conn->header_size = sizeof(struct rxrpc_header);
}
_leave(" = %p{%d}", conn, conn->debug_id);
return conn;
}
/*
* assign a connection ID to a connection and add it to the transport's
* connection lookup tree
* - called with transport client lock held
*/
static void rxrpc_assign_connection_id(struct rxrpc_connection *conn)
{
struct rxrpc_connection *xconn;
struct rb_node *parent, **p;
__be32 epoch;
u32 real_conn_id;
_enter("");
epoch = conn->epoch;
write_lock_bh(&conn->trans->conn_lock);
conn->trans->conn_idcounter += RXRPC_CID_INC;
if (conn->trans->conn_idcounter < RXRPC_CID_INC)
conn->trans->conn_idcounter = RXRPC_CID_INC;
real_conn_id = conn->trans->conn_idcounter;
attempt_insertion:
parent = NULL;
p = &conn->trans->client_conns.rb_node;
while (*p) {
parent = *p;
xconn = rb_entry(parent, struct rxrpc_connection, node);
if (epoch < xconn->epoch)
p = &(*p)->rb_left;
else if (epoch > xconn->epoch)
p = &(*p)->rb_right;
else if (real_conn_id < xconn->real_conn_id)
p = &(*p)->rb_left;
else if (real_conn_id > xconn->real_conn_id)
p = &(*p)->rb_right;
else
goto id_exists;
}
/* we've found a suitable hole - arrange for this connection to occupy
* it */
rb_link_node(&conn->node, parent, p);
rb_insert_color(&conn->node, &conn->trans->client_conns);
conn->real_conn_id = real_conn_id;
conn->cid = htonl(real_conn_id);
write_unlock_bh(&conn->trans->conn_lock);
_leave(" [CONNID %x CID %x]", real_conn_id, ntohl(conn->cid));
return;
/* we found a connection with the proposed ID - walk the tree from that
* point looking for the next unused ID */
id_exists:
for (;;) {
real_conn_id += RXRPC_CID_INC;
if (real_conn_id < RXRPC_CID_INC) {
real_conn_id = RXRPC_CID_INC;
conn->trans->conn_idcounter = real_conn_id;
goto attempt_insertion;
}
parent = rb_next(parent);
if (!parent)
goto attempt_insertion;
xconn = rb_entry(parent, struct rxrpc_connection, node);
if (epoch < xconn->epoch ||
real_conn_id < xconn->real_conn_id)
goto attempt_insertion;
}
}
/*
* add a call to a connection's call-by-ID tree
*/
static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
struct rxrpc_call *call)
{
struct rxrpc_call *xcall;
struct rb_node *parent, **p;
__be32 call_id;
write_lock_bh(&conn->lock);
call_id = call->call_id;
p = &conn->calls.rb_node;
parent = NULL;
while (*p) {
parent = *p;
xcall = rb_entry(parent, struct rxrpc_call, conn_node);
if (call_id < xcall->call_id)
p = &(*p)->rb_left;
else if (call_id > xcall->call_id)
p = &(*p)->rb_right;
else
BUG();
}
rb_link_node(&call->conn_node, parent, p);
rb_insert_color(&call->conn_node, &conn->calls);
write_unlock_bh(&conn->lock);
}
/*
* connect a call on an exclusive connection
*/
static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
__be16 service_id,
struct rxrpc_call *call,
gfp_t gfp)
{
struct rxrpc_connection *conn;
int chan, ret;
_enter("");
conn = rx->conn;
if (!conn) {
/* not yet present - create a candidate for a new connection
* and then redo the check */
conn = rxrpc_alloc_connection(gfp);
if (IS_ERR(conn)) {
_leave(" = %ld", PTR_ERR(conn));
return PTR_ERR(conn);
}
conn->trans = trans;
conn->bundle = NULL;
conn->service_id = service_id;
conn->epoch = rxrpc_epoch;
conn->in_clientflag = 0;
conn->out_clientflag = RXRPC_CLIENT_INITIATED;
conn->cid = 0;
conn->state = RXRPC_CONN_CLIENT;
conn->avail_calls = RXRPC_MAXCALLS - 1;
conn->security_level = rx->min_sec_level;
conn->key = key_get(rx->key);
ret = rxrpc_init_client_conn_security(conn);
if (ret < 0) {
key_put(conn->key);
kfree(conn);
_leave(" = %d [key]", ret);
return ret;
}
write_lock_bh(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock_bh(&rxrpc_connection_lock);
spin_lock(&trans->client_lock);
atomic_inc(&trans->usage);
_net("CONNECT EXCL new %d on TRANS %d",
conn->debug_id, conn->trans->debug_id);
rxrpc_assign_connection_id(conn);
rx->conn = conn;
}
/* we've got a connection with a free channel and we can now attach the
* call to it
* - we're holding the transport's client lock
* - we're holding a reference on the connection
*/
for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
if (!conn->channels[chan])
goto found_channel;
goto no_free_channels;
found_channel:
atomic_inc(&conn->usage);
conn->channels[chan] = call;
call->conn = conn;
call->channel = chan;
call->cid = conn->cid | htonl(chan);
call->call_id = htonl(++conn->call_counter);
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, ntohl(call->call_id));
spin_unlock(&trans->client_lock);
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
no_free_channels:
spin_unlock(&trans->client_lock);
_leave(" = -ENOSR");
return -ENOSR;
}
/*
* find a connection for a call
* - called in process context with IRQs enabled
*/
int rxrpc_connect_call(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
struct rxrpc_conn_bundle *bundle,
struct rxrpc_call *call,
gfp_t gfp)
{
struct rxrpc_connection *conn, *candidate;
int chan, ret;
DECLARE_WAITQUEUE(myself, current);
_enter("%p,%lx,", rx, call->user_call_ID);
if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
return rxrpc_connect_exclusive(rx, trans, bundle->service_id,
call, gfp);
spin_lock(&trans->client_lock);
for (;;) {
/* see if the bundle has a call slot available */
if (!list_empty(&bundle->avail_conns)) {
_debug("avail");
conn = list_entry(bundle->avail_conns.next,
struct rxrpc_connection,
bundle_link);
if (--conn->avail_calls == 0)
list_move(&conn->bundle_link,
&bundle->busy_conns);
ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
ASSERT(conn->channels[0] == NULL ||
conn->channels[1] == NULL ||
conn->channels[2] == NULL ||
conn->channels[3] == NULL);
atomic_inc(&conn->usage);
break;
}
if (!list_empty(&bundle->unused_conns)) {
_debug("unused");
conn = list_entry(bundle->unused_conns.next,
struct rxrpc_connection,
bundle_link);
ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
conn->avail_calls = RXRPC_MAXCALLS - 1;
ASSERT(conn->channels[0] == NULL &&
conn->channels[1] == NULL &&
conn->channels[2] == NULL &&
conn->channels[3] == NULL);
atomic_inc(&conn->usage);
list_move(&conn->bundle_link, &bundle->avail_conns);
break;
}
/* need to allocate a new connection */
_debug("get new conn [%d]", bundle->num_conns);
spin_unlock(&trans->client_lock);
if (signal_pending(current))
goto interrupted;
if (bundle->num_conns >= 20) {
_debug("too many conns");
if (!(gfp & __GFP_WAIT)) {
_leave(" = -EAGAIN");
return -EAGAIN;
}
add_wait_queue(&bundle->chanwait, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (bundle->num_conns < 20 ||
!list_empty(&bundle->unused_conns) ||
!list_empty(&bundle->avail_conns))
break;
if (signal_pending(current))
goto interrupted_dequeue;
schedule();
}
remove_wait_queue(&bundle->chanwait, &myself);
__set_current_state(TASK_RUNNING);
spin_lock(&trans->client_lock);
continue;
}
/* not yet present - create a candidate for a new connection and then
* redo the check */
candidate = rxrpc_alloc_connection(gfp);
if (IS_ERR(candidate)) {
_leave(" = %ld", PTR_ERR(candidate));
return PTR_ERR(candidate);
}
candidate->trans = trans;
candidate->bundle = bundle;
candidate->service_id = bundle->service_id;
candidate->epoch = rxrpc_epoch;
candidate->in_clientflag = 0;
candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
candidate->cid = 0;
candidate->state = RXRPC_CONN_CLIENT;
candidate->avail_calls = RXRPC_MAXCALLS;
candidate->security_level = rx->min_sec_level;
candidate->key = key_get(bundle->key);
ret = rxrpc_init_client_conn_security(candidate);
if (ret < 0) {
key_put(candidate->key);
kfree(candidate);
_leave(" = %d [key]", ret);
return ret;
}
write_lock_bh(&rxrpc_connection_lock);
list_add_tail(&candidate->link, &rxrpc_connections);
write_unlock_bh(&rxrpc_connection_lock);
spin_lock(&trans->client_lock);
list_add(&candidate->bundle_link, &bundle->unused_conns);
bundle->num_conns++;
atomic_inc(&bundle->usage);
atomic_inc(&trans->usage);
_net("CONNECT new %d on TRANS %d",
candidate->debug_id, candidate->trans->debug_id);
rxrpc_assign_connection_id(candidate);
if (candidate->security)
candidate->security->prime_packet_security(candidate);
/* leave the candidate lurking in zombie mode attached to the
* bundle until we're ready for it */
rxrpc_put_connection(candidate);
candidate = NULL;
}
/* we've got a connection with a free channel and we can now attach the
* call to it
* - we're holding the transport's client lock
* - we're holding a reference on the connection
* - we're holding a reference on the bundle
*/
for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
if (!conn->channels[chan])
goto found_channel;
ASSERT(conn->channels[0] == NULL ||
conn->channels[1] == NULL ||
conn->channels[2] == NULL ||
conn->channels[3] == NULL);
BUG();
found_channel:
conn->channels[chan] = call;
call->conn = conn;
call->channel = chan;
call->cid = conn->cid | htonl(chan);
call->call_id = htonl(++conn->call_counter);
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, ntohl(call->call_id));
ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
spin_unlock(&trans->client_lock);
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
interrupted_dequeue:
remove_wait_queue(&bundle->chanwait, &myself);
__set_current_state(TASK_RUNNING);
interrupted:
_leave(" = -ERESTARTSYS");
return -ERESTARTSYS;
}
/*
* get a record of an incoming connection
*/
struct rxrpc_connection *
rxrpc_incoming_connection(struct rxrpc_transport *trans,
struct rxrpc_header *hdr,
gfp_t gfp)
{
struct rxrpc_connection *conn, *candidate = NULL;
struct rb_node *p, **pp;
const char *new = "old";
__be32 epoch;
u32 conn_id;
_enter("");
ASSERT(hdr->flags & RXRPC_CLIENT_INITIATED);
epoch = hdr->epoch;
conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
/* search the connection list first */
read_lock_bh(&trans->conn_lock);
p = trans->server_conns.rb_node;
while (p) {
conn = rb_entry(p, struct rxrpc_connection, node);
_debug("maybe %x", conn->real_conn_id);
if (epoch < conn->epoch)
p = p->rb_left;
else if (epoch > conn->epoch)
p = p->rb_right;
else if (conn_id < conn->real_conn_id)
p = p->rb_left;
else if (conn_id > conn->real_conn_id)
p = p->rb_right;
else
goto found_extant_connection;
}
read_unlock_bh(&trans->conn_lock);
/* not yet present - create a candidate for a new record and then
* redo the search */
candidate = rxrpc_alloc_connection(gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
candidate->trans = trans;
candidate->epoch = hdr->epoch;
candidate->cid = hdr->cid & __constant_cpu_to_be32(RXRPC_CIDMASK);
candidate->service_id = hdr->serviceId;
candidate->security_ix = hdr->securityIndex;
candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
candidate->out_clientflag = 0;
candidate->real_conn_id = conn_id;
candidate->state = RXRPC_CONN_SERVER;
if (candidate->service_id)
candidate->state = RXRPC_CONN_SERVER_UNSECURED;
write_lock_bh(&trans->conn_lock);
pp = &trans->server_conns.rb_node;
p = NULL;
while (*pp) {
p = *pp;
conn = rb_entry(p, struct rxrpc_connection, node);
if (epoch < conn->epoch)
pp = &(*pp)->rb_left;
else if (epoch > conn->epoch)
pp = &(*pp)->rb_right;
else if (conn_id < conn->real_conn_id)
pp = &(*pp)->rb_left;
else if (conn_id > conn->real_conn_id)
pp = &(*pp)->rb_right;
else
goto found_extant_second;
}
/* we can now add the new candidate to the list */
conn = candidate;
candidate = NULL;
rb_link_node(&conn->node, p, pp);
rb_insert_color(&conn->node, &trans->server_conns);
atomic_inc(&conn->trans->usage);
write_unlock_bh(&trans->conn_lock);
write_lock_bh(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock_bh(&rxrpc_connection_lock);
new = "new";
success:
_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->real_conn_id);
_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
return conn;
/* we found the connection in the list immediately */
found_extant_connection:
if (hdr->securityIndex != conn->security_ix) {
read_unlock_bh(&trans->conn_lock);
goto security_mismatch;
}
atomic_inc(&conn->usage);
read_unlock_bh(&trans->conn_lock);
goto success;
/* we found the connection on the second time through the list */
found_extant_second:
if (hdr->securityIndex != conn->security_ix) {
write_unlock_bh(&trans->conn_lock);
goto security_mismatch;
}
atomic_inc(&conn->usage);
write_unlock_bh(&trans->conn_lock);
kfree(candidate);
goto success;
security_mismatch:
kfree(candidate);
_leave(" = -EKEYREJECTED");
return ERR_PTR(-EKEYREJECTED);
}
/*
* find a connection based on transport and RxRPC connection ID for an incoming
* packet
*/
struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
struct rxrpc_header *hdr)
{
struct rxrpc_connection *conn;
struct rb_node *p;
__be32 epoch;
u32 conn_id;
_enter(",{%x,%x}", ntohl(hdr->cid), hdr->flags);
read_lock_bh(&trans->conn_lock);
conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
epoch = hdr->epoch;
if (hdr->flags & RXRPC_CLIENT_INITIATED)
p = trans->server_conns.rb_node;
else
p = trans->client_conns.rb_node;
while (p) {
conn = rb_entry(p, struct rxrpc_connection, node);
_debug("maybe %x", conn->real_conn_id);
if (epoch < conn->epoch)
p = p->rb_left;
else if (epoch > conn->epoch)
p = p->rb_right;
else if (conn_id < conn->real_conn_id)
p = p->rb_left;
else if (conn_id > conn->real_conn_id)
p = p->rb_right;
else
goto found;
}
read_unlock_bh(&trans->conn_lock);
_leave(" = NULL");
return NULL;
found:
atomic_inc(&conn->usage);
read_unlock_bh(&trans->conn_lock);
_leave(" = %p", conn);
return conn;
}
/*
* release a virtual connection
*/
void rxrpc_put_connection(struct rxrpc_connection *conn)
{
_enter("%p{u=%d,d=%d}",
conn, atomic_read(&conn->usage), conn->debug_id);
ASSERTCMP(atomic_read(&conn->usage), >, 0);
conn->put_time = xtime.tv_sec;
if (atomic_dec_and_test(&conn->usage)) {
_debug("zombie");
rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
}
_leave("");
}
/*
* destroy a virtual connection
*/
static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
{
_enter("%p{%d}", conn, atomic_read(&conn->usage));
ASSERTCMP(atomic_read(&conn->usage), ==, 0);
_net("DESTROY CONN %d", conn->debug_id);
if (conn->bundle)
rxrpc_put_bundle(conn->trans, conn->bundle);
ASSERT(RB_EMPTY_ROOT(&conn->calls));
rxrpc_purge_queue(&conn->rx_queue);
rxrpc_clear_conn_security(conn);
rxrpc_put_transport(conn->trans);
kfree(conn);
_leave("");
}
/*
* reap dead connections
*/
void rxrpc_connection_reaper(struct work_struct *work)
{
struct rxrpc_connection *conn, *_p;
unsigned long now, earliest, reap_time;
LIST_HEAD(graveyard);
_enter("");
now = xtime.tv_sec;
earliest = ULONG_MAX;
write_lock_bh(&rxrpc_connection_lock);
list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
_debug("reap CONN %d { u=%d,t=%ld }",
conn->debug_id, atomic_read(&conn->usage),
(long) now - (long) conn->put_time);
if (likely(atomic_read(&conn->usage) > 0))
continue;
spin_lock(&conn->trans->client_lock);
write_lock(&conn->trans->conn_lock);
reap_time = conn->put_time + rxrpc_connection_timeout;
if (atomic_read(&conn->usage) > 0) {
;
} else if (reap_time <= now) {
list_move_tail(&conn->link, &graveyard);
if (conn->out_clientflag)
rb_erase(&conn->node,
&conn->trans->client_conns);
else
rb_erase(&conn->node,
&conn->trans->server_conns);
if (conn->bundle) {
list_del_init(&conn->bundle_link);
conn->bundle->num_conns--;
}
} else if (reap_time < earliest) {
earliest = reap_time;
}
write_unlock(&conn->trans->conn_lock);
spin_unlock(&conn->trans->client_lock);
}
write_unlock_bh(&rxrpc_connection_lock);
if (earliest != ULONG_MAX) {
_debug("reschedule reaper %ld", (long) earliest - now);
ASSERTCMP(earliest, >, now);
rxrpc_queue_delayed_work(&rxrpc_connection_reap,
(earliest - now) * HZ);
}
/* then destroy all those pulled out */
while (!list_empty(&graveyard)) {
conn = list_entry(graveyard.next, struct rxrpc_connection,
link);
list_del_init(&conn->link);
ASSERTCMP(atomic_read(&conn->usage), ==, 0);
rxrpc_destroy_connection(conn);
}
_leave("");
}
/*
* preemptively destroy all the connection records rather than waiting for them
* to time out
*/
void __exit rxrpc_destroy_all_connections(void)
{
_enter("");
rxrpc_connection_timeout = 0;
cancel_delayed_work(&rxrpc_connection_reap);
rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
_leave("");
}
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