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authorDavid Howells <dhowells@redhat.com>2007-04-26 18:50:17 -0400
committerDavid S. Miller <davem@davemloft.net>2007-04-26 18:50:17 -0400
commit651350d10f93bed7003c9a66e24cf25e0f8eed3d (patch)
tree4748c1dd0b1a905b0e34b100c3c6ced6565a06de /net/rxrpc/ar-connection.c
parentec26815ad847dbf74a1e27aa5515fb7d5dc6ee6f (diff)
[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>
Diffstat (limited to 'net/rxrpc/ar-connection.c')
-rw-r--r--net/rxrpc/ar-connection.c28
1 files changed, 22 insertions, 6 deletions
diff --git a/net/rxrpc/ar-connection.c b/net/rxrpc/ar-connection.c
index 01eb33c30571..43cb3e051ece 100644
--- a/net/rxrpc/ar-connection.c
+++ b/net/rxrpc/ar-connection.c
@@ -356,7 +356,7 @@ static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
356 conn->out_clientflag = RXRPC_CLIENT_INITIATED; 356 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
357 conn->cid = 0; 357 conn->cid = 0;
358 conn->state = RXRPC_CONN_CLIENT; 358 conn->state = RXRPC_CONN_CLIENT;
359 conn->avail_calls = RXRPC_MAXCALLS; 359 conn->avail_calls = RXRPC_MAXCALLS - 1;
360 conn->security_level = rx->min_sec_level; 360 conn->security_level = rx->min_sec_level;
361 conn->key = key_get(rx->key); 361 conn->key = key_get(rx->key);
362 362
@@ -447,6 +447,11 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
447 if (--conn->avail_calls == 0) 447 if (--conn->avail_calls == 0)
448 list_move(&conn->bundle_link, 448 list_move(&conn->bundle_link,
449 &bundle->busy_conns); 449 &bundle->busy_conns);
450 ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
451 ASSERT(conn->channels[0] == NULL ||
452 conn->channels[1] == NULL ||
453 conn->channels[2] == NULL ||
454 conn->channels[3] == NULL);
450 atomic_inc(&conn->usage); 455 atomic_inc(&conn->usage);
451 break; 456 break;
452 } 457 }
@@ -456,6 +461,12 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
456 conn = list_entry(bundle->unused_conns.next, 461 conn = list_entry(bundle->unused_conns.next,
457 struct rxrpc_connection, 462 struct rxrpc_connection,
458 bundle_link); 463 bundle_link);
464 ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
465 conn->avail_calls = RXRPC_MAXCALLS - 1;
466 ASSERT(conn->channels[0] == NULL &&
467 conn->channels[1] == NULL &&
468 conn->channels[2] == NULL &&
469 conn->channels[3] == NULL);
459 atomic_inc(&conn->usage); 470 atomic_inc(&conn->usage);
460 list_move(&conn->bundle_link, &bundle->avail_conns); 471 list_move(&conn->bundle_link, &bundle->avail_conns);
461 break; 472 break;
@@ -512,7 +523,7 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
512 candidate->state = RXRPC_CONN_CLIENT; 523 candidate->state = RXRPC_CONN_CLIENT;
513 candidate->avail_calls = RXRPC_MAXCALLS; 524 candidate->avail_calls = RXRPC_MAXCALLS;
514 candidate->security_level = rx->min_sec_level; 525 candidate->security_level = rx->min_sec_level;
515 candidate->key = key_get(rx->key); 526 candidate->key = key_get(bundle->key);
516 527
517 ret = rxrpc_init_client_conn_security(candidate); 528 ret = rxrpc_init_client_conn_security(candidate);
518 if (ret < 0) { 529 if (ret < 0) {
@@ -555,6 +566,10 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
555 for (chan = 0; chan < RXRPC_MAXCALLS; chan++) 566 for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
556 if (!conn->channels[chan]) 567 if (!conn->channels[chan])
557 goto found_channel; 568 goto found_channel;
569 ASSERT(conn->channels[0] == NULL ||
570 conn->channels[1] == NULL ||
571 conn->channels[2] == NULL ||
572 conn->channels[3] == NULL);
558 BUG(); 573 BUG();
559 574
560found_channel: 575found_channel:
@@ -567,6 +582,7 @@ found_channel:
567 _net("CONNECT client on conn %d chan %d as call %x", 582 _net("CONNECT client on conn %d chan %d as call %x",
568 conn->debug_id, chan, ntohl(call->call_id)); 583 conn->debug_id, chan, ntohl(call->call_id));
569 584
585 ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
570 spin_unlock(&trans->client_lock); 586 spin_unlock(&trans->client_lock);
571 587
572 rxrpc_add_call_ID_to_conn(conn, call); 588 rxrpc_add_call_ID_to_conn(conn, call);
@@ -778,7 +794,7 @@ void rxrpc_put_connection(struct rxrpc_connection *conn)
778 conn->put_time = xtime.tv_sec; 794 conn->put_time = xtime.tv_sec;
779 if (atomic_dec_and_test(&conn->usage)) { 795 if (atomic_dec_and_test(&conn->usage)) {
780 _debug("zombie"); 796 _debug("zombie");
781 schedule_delayed_work(&rxrpc_connection_reap, 0); 797 rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
782 } 798 }
783 799
784 _leave(""); 800 _leave("");
@@ -862,8 +878,8 @@ void rxrpc_connection_reaper(struct work_struct *work)
862 if (earliest != ULONG_MAX) { 878 if (earliest != ULONG_MAX) {
863 _debug("reschedule reaper %ld", (long) earliest - now); 879 _debug("reschedule reaper %ld", (long) earliest - now);
864 ASSERTCMP(earliest, >, now); 880 ASSERTCMP(earliest, >, now);
865 schedule_delayed_work(&rxrpc_connection_reap, 881 rxrpc_queue_delayed_work(&rxrpc_connection_reap,
866 (earliest - now) * HZ); 882 (earliest - now) * HZ);
867 } 883 }
868 884
869 /* then destroy all those pulled out */ 885 /* then destroy all those pulled out */
@@ -889,7 +905,7 @@ void __exit rxrpc_destroy_all_connections(void)
889 905
890 rxrpc_connection_timeout = 0; 906 rxrpc_connection_timeout = 0;
891 cancel_delayed_work(&rxrpc_connection_reap); 907 cancel_delayed_work(&rxrpc_connection_reap);
892 schedule_delayed_work(&rxrpc_connection_reap, 0); 908 rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
893 909
894 _leave(""); 910 _leave("");
895} 911}