From d001648ec7cf8b21ae9eec8b9ba4a18295adfb14 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 30 Aug 2016 20:42:14 +0100 Subject: rxrpc: Don't expose skbs to in-kernel users [ver #2] Don't expose skbs to in-kernel users, such as the AFS filesystem, but instead provide a notification hook the indicates that a call needs attention and another that indicates that there's a new call to be collected. This makes the following possibilities more achievable: (1) Call refcounting can be made simpler if skbs don't hold refs to calls. (2) skbs referring to non-data events will be able to be freed much sooner rather than being queued for AFS to pick up as rxrpc_kernel_recv_data will be able to consult the call state. (3) We can shortcut the receive phase when a call is remotely aborted because we don't have to go through all the packets to get to the one cancelling the operation. (4) It makes it easier to do encryption/decryption directly between AFS's buffers and sk_buffs. (5) Encryption/decryption can more easily be done in the AFS's thread contexts - usually that of the userspace process that issued a syscall - rather than in one of rxrpc's background threads on a workqueue. (6) AFS will be able to wait synchronously on a call inside AF_RXRPC. To make this work, the following interface function has been added: int rxrpc_kernel_recv_data( struct socket *sock, struct rxrpc_call *call, void *buffer, size_t bufsize, size_t *_offset, bool want_more, u32 *_abort_code); This is the recvmsg equivalent. It allows the caller to find out about the state of a specific call and to transfer received data into a buffer piecemeal. afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction logic between them. They don't wait synchronously yet because the socket lock needs to be dealt with. Five interface functions have been removed: rxrpc_kernel_is_data_last() rxrpc_kernel_get_abort_code() rxrpc_kernel_get_error_number() rxrpc_kernel_free_skb() rxrpc_kernel_data_consumed() As a temporary hack, sk_buffs going to an in-kernel call are queued on the rxrpc_call struct (->knlrecv_queue) rather than being handed over to the in-kernel user. To process the queue internally, a temporary function, temp_deliver_data() has been added. This will be replaced with common code between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a future patch. Signed-off-by: David Howells Signed-off-by: David S. Miller --- net/rxrpc/ar-internal.h | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) (limited to 'net/rxrpc/ar-internal.h') diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 0c320b2b7b43..4e86d248dc5e 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -39,6 +39,20 @@ struct rxrpc_crypt { struct rxrpc_connection; +/* + * Mark applied to socket buffers. + */ +enum rxrpc_skb_mark { + RXRPC_SKB_MARK_DATA, /* data message */ + RXRPC_SKB_MARK_FINAL_ACK, /* final ACK received message */ + RXRPC_SKB_MARK_BUSY, /* server busy message */ + RXRPC_SKB_MARK_REMOTE_ABORT, /* remote abort message */ + RXRPC_SKB_MARK_LOCAL_ABORT, /* local abort message */ + RXRPC_SKB_MARK_NET_ERROR, /* network error message */ + RXRPC_SKB_MARK_LOCAL_ERROR, /* local error message */ + RXRPC_SKB_MARK_NEW_CALL, /* local error message */ +}; + /* * sk_state for RxRPC sockets */ @@ -57,7 +71,7 @@ enum { struct rxrpc_sock { /* WARNING: sk has to be the first member */ struct sock sk; - rxrpc_interceptor_t interceptor; /* kernel service Rx interceptor function */ + rxrpc_notify_new_call_t notify_new_call; /* Func to notify of new call */ struct rxrpc_local *local; /* local endpoint */ struct list_head listen_link; /* link in the local endpoint's listen list */ struct list_head secureq; /* calls awaiting connection security clearance */ @@ -367,6 +381,7 @@ enum rxrpc_call_flag { RXRPC_CALL_EXPECT_OOS, /* expect out of sequence packets */ RXRPC_CALL_IS_SERVICE, /* Call is service call */ RXRPC_CALL_EXPOSED, /* The call was exposed to the world */ + RXRPC_CALL_RX_NO_MORE, /* Don't indicate MSG_MORE from recvmsg() */ }; /* @@ -441,6 +456,7 @@ struct rxrpc_call { struct timer_list resend_timer; /* Tx resend timer */ struct work_struct destroyer; /* call destroyer */ struct work_struct processor; /* packet processor and ACK generator */ + rxrpc_notify_rx_t notify_rx; /* kernel service Rx notification function */ struct list_head link; /* link in master call list */ struct list_head chan_wait_link; /* Link in conn->waiting_calls */ struct hlist_node error_link; /* link in error distribution list */ @@ -448,6 +464,7 @@ struct rxrpc_call { struct rb_node sock_node; /* node in socket call tree */ struct sk_buff_head rx_queue; /* received packets */ struct sk_buff_head rx_oos_queue; /* packets received out of sequence */ + struct sk_buff_head knlrecv_queue; /* Queue for kernel_recv [TODO: replace this] */ struct sk_buff *tx_pending; /* Tx socket buffer being filled */ wait_queue_head_t waitq; /* Wait queue for channel or Tx */ __be32 crypto_buf[2]; /* Temporary packet crypto buffer */ @@ -512,7 +529,8 @@ extern struct workqueue_struct *rxrpc_workqueue; * call_accept.c */ void rxrpc_accept_incoming_calls(struct rxrpc_local *); -struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *, unsigned long); +struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *, unsigned long, + rxrpc_notify_rx_t); int rxrpc_reject_call(struct rxrpc_sock *); /* @@ -874,6 +892,7 @@ int rxrpc_init_server_conn_security(struct rxrpc_connection *); /* * skbuff.c */ +void rxrpc_kernel_data_consumed(struct rxrpc_call *, struct sk_buff *); void rxrpc_packet_destructor(struct sk_buff *); void rxrpc_new_skb(struct sk_buff *); void rxrpc_see_skb(struct sk_buff *); -- cgit v1.2.3-55-g7522