22 Sep, 2016

1 commit

  • Don't store the rxrpc protocol header in sk_buffs on the transmit queue,
    but rather generate it on the fly and pass it to kernel_sendmsg() as a
    separate iov. This reduces the amount of storage required.

    Note that the security header is still stored in the sk_buff as it may get
    encrypted along with the data (and doesn't change with each transmission).

    Signed-off-by: David Howells

    David Howells
     

17 Sep, 2016

2 commits


14 Sep, 2016

1 commit

  • Add IPv6 support to AF_RXRPC. With this, AF_RXRPC sockets can be created:

    service = socket(AF_RXRPC, SOCK_DGRAM, PF_INET6);

    instead of:

    service = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);

    The AFS filesystem doesn't support IPv6 at the moment, though, since that
    requires upgrades to some of the RPC calls.

    Note that a good portion of this patch is replacing "%pI4:%u" in print
    statements with "%pISpc" which is able to handle both protocols and print
    the port.

    Signed-off-by: David Howells

    David Howells
     

08 Sep, 2016

2 commits

  • Rewrite the data and ack handling code such that:

    (1) Parsing of received ACK and ABORT packets and the distribution and the
    filing of DATA packets happens entirely within the data_ready context
    called from the UDP socket. This allows us to process and discard ACK
    and ABORT packets much more quickly (they're no longer stashed on a
    queue for a background thread to process).

    (2) We avoid calling skb_clone(), pskb_pull() and pskb_trim(). We instead
    keep track of the offset and length of the content of each packet in
    the sk_buff metadata. This means we don't do any allocation in the
    receive path.

    (3) Jumbo DATA packet parsing is now done in data_ready context. Rather
    than cloning the packet once for each subpacket and pulling/trimming
    it, we file the packet multiple times with an annotation for each
    indicating which subpacket is there. From that we can directly
    calculate the offset and length.

    (4) A call's receive queue can be accessed without taking locks (memory
    barriers do have to be used, though).

    (5) Incoming calls are set up from preallocated resources and immediately
    made live. They can than have packets queued upon them and ACKs
    generated. If insufficient resources exist, DATA packet #1 is given a
    BUSY reply and other DATA packets are discarded).

    (6) sk_buffs no longer take a ref on their parent call.

    To make this work, the following changes are made:

    (1) Each call's receive buffer is now a circular buffer of sk_buff
    pointers (rxtx_buffer) rather than a number of sk_buff_heads spread
    between the call and the socket. This permits each sk_buff to be in
    the buffer multiple times. The receive buffer is reused for the
    transmit buffer.

    (2) A circular buffer of annotations (rxtx_annotations) is kept parallel
    to the data buffer. Transmission phase annotations indicate whether a
    buffered packet has been ACK'd or not and whether it needs
    retransmission.

    Receive phase annotations indicate whether a slot holds a whole packet
    or a jumbo subpacket and, if the latter, which subpacket. They also
    note whether the packet has been decrypted in place.

    (3) DATA packet window tracking is much simplified. Each phase has just
    two numbers representing the window (rx_hard_ack/rx_top and
    tx_hard_ack/tx_top).

    The hard_ack number is the sequence number before base of the window,
    representing the last packet the other side says it has consumed.
    hard_ack starts from 0 and the first packet is sequence number 1.

    The top number is the sequence number of the highest-numbered packet
    residing in the buffer. Packets between hard_ack+1 and top are
    soft-ACK'd to indicate they've been received, but not yet consumed.

    Four macros, before(), before_eq(), after() and after_eq() are added
    to compare sequence numbers within the window. This allows for the
    top of the window to wrap when the hard-ack sequence number gets close
    to the limit.

    Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also
    to indicate when rx_top and tx_top point at the packets with the
    LAST_PACKET bit set, indicating the end of the phase.

    (4) Calls are queued on the socket 'receive queue' rather than packets.
    This means that we don't need have to invent dummy packets to queue to
    indicate abnormal/terminal states and we don't have to keep metadata
    packets (such as ABORTs) around

    (5) The offset and length of a (sub)packet's content are now passed to
    the verify_packet security op. This is currently expected to decrypt
    the packet in place and validate it.

    However, there's now nowhere to store the revised offset and length of
    the actual data within the decrypted blob (there may be a header and
    padding to skip) because an sk_buff may represent multiple packets, so
    a locate_data security op is added to retrieve these details from the
    sk_buff content when needed.

    (6) recvmsg() now has to handle jumbo subpackets, where each subpacket is
    individually secured and needs to be individually decrypted. The code
    to do this is broken out into rxrpc_recvmsg_data() and shared with the
    kernel API. It now iterates over the call's receive buffer rather
    than walking the socket receive queue.

    Additional changes:

    (1) The timers are condensed to a single timer that is set for the soonest
    of three timeouts (delayed ACK generation, DATA retransmission and
    call lifespan).

    (2) Transmission of ACK and ABORT packets is effected immediately from
    process-context socket ops/kernel API calls that cause them instead of
    them being punted off to a background work item. The data_ready
    handler still has to defer to the background, though.

    (3) A shutdown op is added to the AF_RXRPC socket so that the AFS
    filesystem can shut down the socket and flush its own work items
    before closing the socket to deal with any in-progress service calls.

    Future additional changes that will need to be considered:

    (1) Make sure that a call doesn't hog the front of the queue by receiving
    data from the network as fast as userspace is consuming it to the
    exclusion of other calls.

    (2) Transmit delayed ACKs from within recvmsg() when we've consumed
    sufficiently more packets to avoid the background work item needing to
    run.

    Signed-off-by: David Howells

    David Howells
     
  • Make it possible for the data_ready handler called from the UDP transport
    socket to completely instantiate an rxrpc_call structure and make it
    immediately live by preallocating all the memory it might need. The idea
    is to cut out the background thread usage as much as possible.

    [Note that the preallocated structs are not actually used in this patch -
    that will be done in a future patch.]

    If insufficient resources are available in the preallocation buffers, it
    will be possible to discard the DATA packet in the data_ready handler or
    schedule a BUSY packet without the need to schedule an attempt at
    allocation in a background thread.

    To this end:

    (1) Preallocate rxrpc_peer, rxrpc_connection and rxrpc_call structs to a
    maximum number each of the listen backlog size. The backlog size is
    limited to a maxmimum of 32. Only this many of each can be in the
    preallocation buffer.

    (2) For userspace sockets, the preallocation is charged initially by
    listen() and will be recharged by accepting or rejecting pending
    new incoming calls.

    (3) For kernel services {,re,dis}charging of the preallocation buffers is
    handled manually. Two notifier callbacks have to be provided before
    kernel_listen() is invoked:

    (a) An indication that a new call has been instantiated. This can be
    used to trigger background recharging.

    (b) An indication that a call is being discarded. This is used when
    the socket is being released.

    A function, rxrpc_kernel_charge_accept() is called by the kernel
    service to preallocate a single call. It should be passed the user ID
    to be used for that call and a callback to associate the rxrpc call
    with the kernel service's side of the ID.

    (4) Discard the preallocation when the socket is closed.

    (5) Temporarily bump the refcount on the call allocated in
    rxrpc_incoming_call() so that rxrpc_release_call() can ditch the
    preallocation ref on service calls unconditionally. This will no
    longer be necessary once the preallocation is used.

    Note that this does not yet control the number of active service calls on a
    client - that will come in a later patch.

    A future development would be to provide a setsockopt() call that allows a
    userspace server to manually charge the preallocation buffer. This would
    allow user call IDs to be provided in advance and the awkward manual accept
    stage to be bypassed.

    Signed-off-by: David Howells

    David Howells
     

30 Aug, 2016

1 commit

  • Condense the terminal states of a call state machine to a single state,
    plus a separate completion type value. The value is then set, along with
    error and abort code values, only when the call is transitioned to the
    completion state.

    Helpers are provided to simplify this.

    Signed-off-by: David Howells

    David Howells
     

24 Aug, 2016

2 commits

  • Improve the management and caching of client rxrpc connection objects.
    From this point, client connections will be managed separately from service
    connections because AF_RXRPC controls the creation and re-use of client
    connections but doesn't have that luxury with service connections.

    Further, there will be limits on the numbers of client connections that may
    be live on a machine. No direct restriction will be placed on the number
    of client calls, excepting that each client connection can support a
    maximum of four concurrent calls.

    Note that, for a number of reasons, we don't want to simply discard a
    client connection as soon as the last call is apparently finished:

    (1) Security is negotiated per-connection and the context is then shared
    between all calls on that connection. The context can be negotiated
    again if the connection lapses, but that involves holding up calls
    whilst at least two packets are exchanged and various crypto bits are
    performed - so we'd ideally like to cache it for a little while at
    least.

    (2) If a packet goes astray, we will need to retransmit a final ACK or
    ABORT packet. To make this work, we need to keep around the
    connection details for a little while.

    (3) The locally held structures represent some amount of setup time, to be
    weighed against their occupation of memory when idle.

    To this end, the client connection cache is managed by a state machine on
    each connection. There are five states:

    (1) INACTIVE - The connection is not held in any list and may not have
    been exposed to the world. If it has been previously exposed, it was
    discarded from the idle list after expiring.

    (2) WAITING - The connection is waiting for the number of client conns to
    drop below the maximum capacity. Calls may be in progress upon it
    from when it was active and got culled.

    The connection is on the rxrpc_waiting_client_conns list which is kept
    in to-be-granted order. Culled conns with waiters go to the back of
    the queue just like new conns.

    (3) ACTIVE - The connection has at least one call in progress upon it, it
    may freely grant available channels to new calls and calls may be
    waiting on it for channels to become available.

    The connection is on the rxrpc_active_client_conns list which is kept
    in activation order for culling purposes.

    (4) CULLED - The connection got summarily culled to try and free up
    capacity. Calls currently in progress on the connection are allowed
    to continue, but new calls will have to wait. There can be no waiters
    in this state - the conn would have to go to the WAITING state
    instead.

    (5) IDLE - The connection has no calls in progress upon it and must have
    been exposed to the world (ie. the EXPOSED flag must be set). When it
    expires, the EXPOSED flag is cleared and the connection transitions to
    the INACTIVE state.

    The connection is on the rxrpc_idle_client_conns list which is kept in
    order of how soon they'll expire.

    A connection in the ACTIVE or CULLED state must have at least one active
    call upon it; if in the WAITING state it may have active calls upon it;
    other states may not have active calls.

    As long as a connection remains active and doesn't get culled, it may
    continue to process calls - even if there are connections on the wait
    queue. This simplifies things a bit and reduces the amount of checking we
    need do.

    There are a couple flags of relevance to the cache:

    (1) EXPOSED - The connection ID got exposed to the world. If this flag is
    set, an extra ref is added to the connection preventing it from being
    reaped when it has no calls outstanding. This flag is cleared and the
    ref dropped when a conn is discarded from the idle list.

    (2) DONT_REUSE - The connection should be discarded as soon as possible and
    should not be reused.

    This commit also provides a number of new settings:

    (*) /proc/net/rxrpc/max_client_conns

    The maximum number of live client connections. Above this number, new
    connections get added to the wait list and must wait for an active
    conn to be culled. Culled connections can be reused, but they will go
    to the back of the wait list and have to wait.

    (*) /proc/net/rxrpc/reap_client_conns

    If the number of desired connections exceeds the maximum above, the
    active connection list will be culled until there are only this many
    left in it.

    (*) /proc/net/rxrpc/idle_conn_expiry

    The normal expiry time for a client connection, provided there are
    fewer than reap_client_conns of them around.

    (*) /proc/net/rxrpc/idle_conn_fast_expiry

    The expedited expiry time, used when there are more than
    reap_client_conns of them around.

    Note that I combined the Tx wait queue with the channel grant wait queue to
    save space as only one of these should be in use at once.

    Note also that, for the moment, the service connection cache still uses the
    old connection management code.

    Signed-off-by: David Howells

    David Howells
     
  • The main connection list is used for two independent purposes: primarily it
    is used to find connections to reap and secondarily it is used to list
    connections in procfs.

    Split the procfs list out from the reap list. This allows us to stop using
    the reap list for client connections when they acquire a separate
    management strategy from service collections.

    The client connections will not be on a management single list, and sometimes
    won't be on a management list at all. This doesn't leave them floating,
    however, as they will also be on an rb-tree rooted on the socket so that the
    socket can find them to dispatch calls.

    Signed-off-by: David Howells

    David Howells
     

23 Aug, 2016

3 commits

  • Perform terminal call ACK/ABORT retransmission in the connection processor
    rather than in the call processor. With this change, once last_call is
    set, no more incoming packets will be routed to the corresponding call or
    any earlier calls on that channel (call IDs must only increase on a channel
    on a connection).

    Further, if a packet's callNumber is before the last_call ID or a packet is
    aimed at successfully completed service call then that packet is discarded
    and ignored.

    Signed-off-by: David Howells

    David Howells
     
  • Set the connection expiry time when a connection becomes idle rather than
    doing this in rxrpc_put_connection(). This makes the put path more
    efficient (it is likely to be called occasionally whilst a connection has
    outstanding calls because active workqueue items needs to be given a ref).

    The time is also preset in the connection allocator in case the connection
    never gets used.

    Signed-off-by: David Howells

    David Howells
     
  • Drop the channel number (channel) field from the rxrpc_call struct to
    reduce the size of the call struct. The field is redundant: if the call is
    attached to a connection, the channel can be obtained from there by AND'ing
    with RXRPC_CHANNELMASK.

    Signed-off-by: David Howells

    David Howells
     

06 Jul, 2016

12 commits

  • Move to using RCU access to a peer's service connection tree when routing
    an incoming packet. This is done using a seqlock to trigger retrying of
    the tree walk if a change happened.

    Further, we no longer get a ref on the connection looked up in the
    data_ready handler unless we queue the connection's work item - and then
    only if the refcount > 0.

    Note that I'm avoiding the use of a hash table for service connections
    because each service connection is addressed by a 62-bit number
    (constructed from epoch and connection ID >> 2) that would allow the client
    to engage in bucket stuffing, given knowledge of the hash algorithm.
    Peers, however, are hashed as the network address is less controllable by
    the client. The total number of peers will also be limited in a future
    commit.

    Signed-off-by: David Howells

    David Howells
     
  • Move the peer lookup done in input.c by data_ready into
    rxrpc_find_connection().

    Signed-off-by: David Howells

    David Howells
     
  • Overhaul the usage count accounting for the rxrpc_connection struct to make
    it easier to implement RCU access from the data_ready handler.

    The problem is that currently we're using a lock to prevent the garbage
    collector from trying to clean up a connection that we're contemplating
    unidling. We could just stick incoming packets on the connection we find,
    but we've then got a problem that we may race when dispatching a work item
    to process it as we need to give that a ref to prevent the rxrpc_connection
    struct from disappearing in the meantime.

    Further, incoming packets may get discarded if attached to an
    rxrpc_connection struct that is going away. Whilst this is not a total
    disaster - the client will presumably resend - it would delay processing of
    the call. This would affect the AFS client filesystem's service manager
    operation.

    To this end:

    (1) We now maintain an extra count on the connection usage count whilst it
    is on the connection list. This mean it is not in use when its
    refcount is 1.

    (2) When trying to reuse an old connection, we only increment the refcount
    if it is greater than 0. If it is 0, we replace it in the tree with a
    new candidate connection.

    (3) Two connection flags are added to indicate whether or not a connection
    is in the local's client connection tree (used by sendmsg) or the
    peer's service connection tree (used by data_ready). This makes sure
    that we don't try and remove a connection if it got replaced.

    The flags are tested under lock with the removal operation to prevent
    the reaper from killing the rxrpc_connection struct whilst someone
    else is trying to effect a replacement.

    This could probably be alleviated by using memory barriers between the
    flag set/test and the rb_tree ops. The rb_tree op would still need to
    be under the lock, however.

    (4) When trying to reap an old connection, we try to flip the usage count
    from 1 to 0. If it's not 1 at that point, then it must've come back
    to life temporarily and we ignore it.

    Signed-off-by: David Howells

    David Howells
     
  • Split the service-specific connection code out into into its own file. The
    client-specific code has already been split out. This will leave just the
    common code in the original file.

    Signed-off-by: David Howells

    David Howells
     
  • Split the client-specific connection code out into its own file. It will
    behave somewhat differently from the service-specific connection code, so
    it makes sense to separate them.

    Signed-off-by: David Howells

    David Howells
     
  • Each channel on a connection has a separate, independent number space from
    which to allocate callNumber values. It is entirely possible, for example,
    to have a connection with four active calls, each with call number 1.

    Note that the callNumber values for any particular channel don't have to
    start at 1, but they are supposed to increment monotonically for that
    channel from a client's perspective and may not be reused once the call
    number is transmitted (until the epoch cycles all the way back round).

    Currently, however, call numbers are allocated on a per-connection basis
    and, further, are held in an rb-tree. The rb-tree is redundant as the four
    channel pointers in the rxrpc_connection struct are entirely capable of
    pointing to all the calls currently in progress on a connection.

    To this end, make the following changes:

    (1) Handle call number allocation independently per channel.

    (2) Get rid of the conn->calls rb-tree. This is overkill as a connection
    may have a maximum of four calls in progress at any one time. Use the
    pointers in the channels[] array instead, indexed by the channel
    number from the packet.

    (3) For each channel, save the result of the last call that was in
    progress on that channel in conn->channels[] so that the final ACK or
    ABORT packet can be replayed if necessary. Any call earlier than that
    is just ignored. If we've seen the next call number in a packet, the
    last one is most definitely defunct.

    (4) When generating a RESPONSE packet for a connection, the call number
    counter for each channel must be included in it.

    (5) When parsing a RESPONSE packet for a connection, the call number
    counters contained therein should be used to set the minimum expected
    call numbers on each channel.

    To do in future commits:

    (1) Replay terminal packets based on the last call stored in
    conn->channels[].

    (2) Connections should be retired before the callNumber space on any
    channel runs out.

    (3) A server is expected to disregard or reject any new incoming call that
    has a call number less than the current call number counter. The call
    number counter for that channel must be advanced to the new call
    number.

    Note that the server cannot just require that the next call that it
    sees on a channel be exactly the call number counter + 1 because then
    there's a scenario that could cause a problem: The client transmits a
    packet to initiate a connection, the network goes out, the server
    sends an ACK (which gets lost), the client sends an ABORT (which also
    gets lost); the network then reconnects, the client then reuses the
    call number for the next call (it doesn't know the server already saw
    the call number), but the server thinks it already has the first
    packet of this call (it doesn't know that the client doesn't know that
    it saw the call number the first time).

    Signed-off-by: David Howells

    David Howells
     
  • Add RCU destruction for connections and calls as the RCU lookup from the
    transport socket data_ready handler is going to come along shortly.

    Whilst we're at it, move the cleanup workqueue flushing and RCU barrierage
    into the destruction code for the objects that need it (locals and
    connections) and add the extra RCU barrier required for connection cleanup.

    Signed-off-by: David Howells

    David Howells
     
  • When a call is disconnected, clear the call's pointer to the connection and
    release the associated ref on that connection. This means that the call no
    longer pins the connection and the connection can be discarded even before
    the call is.

    As the code currently stands, the call struct is effectively pinned by
    userspace until userspace has enacted a recvmsg() to retrieve the final
    call state as sk_buffs on the receive queue pin the call to which they're
    related because:

    (1) The rxrpc_call struct contains the userspace ID that recvmsg() has to
    include in the control message buffer to indicate which call is being
    referred to. This ID must remain valid until the terminal packet is
    completely read and must be invalidated immediately at that point as
    userspace is entitled to immediately reuse it.

    (2) The final ACK to the reply to a client call isn't sent until the last
    data packet is entirely read (it's probably worth altering this in
    future to be send the ACK as soon as all the data has been received).

    This change requires a bit of rearrangement to make sure that the call
    isn't going to try and access the connection again after protocol
    completion:

    (1) Delete the error link earlier when we're releasing the call. Possibly
    network errors should be distributed via connections at the cost of
    adding in an access to the rxrpc_connection struct.

    (2) Remove the call from the connection's call tree before disconnecting
    the call. The call tree needs to be removed anyway and incoming
    packets delivered by channel pointer instead.

    (3) The release call event should be considered last after all other
    events have been processed so that we don't need access to the
    connection again.

    (4) Move the channel_lock taking from rxrpc_release_call() to
    rxrpc_disconnect_call() where it will be required in future.

    Signed-off-by: David Howells

    David Howells
     
  • Turn the connection event and state #define lists into enums and move
    outside of the struct definition.

    Whilst we're at it, change _SERVER to _SERVICE in those identifiers and add
    EV_ into the event name to distinguish them from flags and states.

    Also add a symbol indicating the number of states and use that in the state
    text array.

    Signed-off-by: David Howells

    David Howells
     
  • rxkad uses stack memory in SG lists which would not work if stacks were
    allocated from vmalloc memory. In fact, in most cases this isn't even
    necessary as the stack memory ends up getting copied over to kmalloc
    memory.

    This patch eliminates all the unnecessary stack memory uses by supplying
    the final destination directly to the crypto API. In two instances where a
    temporary buffer is actually needed we also switch use a scratch area in
    the rxrpc_call struct (only one DATA packet will be being secured or
    verified at a time).

    Finally there is no need to split a split-page buffer into two SG entries
    so code dealing with that has been removed.

    Signed-off-by: Herbert Xu
    Signed-off-by: Andy Lutomirski
    Signed-off-by: David Howells

    Herbert Xu
     
  • When looking up a client connection to which to route a packet, we need to
    check that the packet came from the correct source so that a peer can't try
    to muck around with another peer's connection.

    Signed-off-by: David Howells

    David Howells
     
  • Fix the following sparse errors:

    ../net/rxrpc/conn_object.c:77:17: warning: incorrect type in assignment (different base types)
    ../net/rxrpc/conn_object.c:77:17: expected restricted __be32 [usertype] call_id
    ../net/rxrpc/conn_object.c:77:17: got unsigned int [unsigned] [usertype] call_id
    ../net/rxrpc/conn_object.c:84:21: warning: restricted __be32 degrades to integer
    ../net/rxrpc/conn_object.c:86:26: warning: restricted __be32 degrades to integer
    ../net/rxrpc/conn_object.c:357:15: warning: incorrect type in assignment (different base types)
    ../net/rxrpc/conn_object.c:357:15: expected restricted __be32 [usertype] epoch
    ../net/rxrpc/conn_object.c:357:15: got unsigned int [unsigned] [usertype] epoch
    ../net/rxrpc/conn_object.c:369:21: warning: restricted __be32 degrades to integer
    ../net/rxrpc/conn_object.c:371:26: warning: restricted __be32 degrades to integer
    ../net/rxrpc/conn_object.c:411:21: warning: restricted __be32 degrades to integer
    ../net/rxrpc/conn_object.c:413:26: warning: restricted __be32 degrades to integer

    Signed-off-by: David Howells

    David Howells
     

22 Jun, 2016

8 commits

  • The rxrpc_transport struct is now redundant, given that the rxrpc_peer
    struct is now per peer port rather than per peer host, so get rid of it.

    Service connection lists are transferred to the rxrpc_peer struct, as is
    the conn_lock. Previous patches moved the client connection handling out
    of the rxrpc_transport struct and discarded the connection bundling code.

    Signed-off-by: David Howells

    David Howells
     
  • Kill off the concept of maintaining a bundle of connections to a particular
    target service to increase the number of call slots available for any
    beyond four for that service (there are four call slots per connection).

    This will make cleaning up the connection handling code easier and
    facilitate removal of the rxrpc_transport struct. Bundling can be
    reintroduced later if necessary.

    Signed-off-by: David Howells

    David Howells
     
  • Provide refcount helper functions for connections so that the code doesn't
    touch local or connection usage counts directly.

    Also make it such that local and peer put functions can take a NULL
    pointer.

    Signed-off-by: David Howells

    David Howells
     
  • Use the IDR facility to allocate client connection IDs on a machine-wide
    basis so that each client connection has a unique identifier. When the
    connection ID space wraps, we advance the epoch by 1, thereby effectively
    having a 62-bit ID space. The IDR facility is then used to look up client
    connections during incoming packet routing instead of using an rbtree
    rooted on the transport.

    This change allows for the removal of the transport in the future and also
    means that client connections can be looked up directly in the data-ready
    handler by connection ID.

    The ID management code is placed in a new file, conn-client.c, to which all
    the client connection-specific code will eventually move.

    Note that the IDR tree gets very expensive on memory if the connection IDs
    are widely scattered throughout the number space, so we shall need to
    retire connections that have, say, an ID more than four times the maximum
    number of client conns away from the current allocation point to try and
    keep the IDs concentrated. We will also need to retire connections from an
    old epoch.

    Also note that, for the moment, a pointer to the transport has to be passed
    through into the ID allocation function so that we can take a BH lock to
    prevent a locking issue against in-BH lookup of client connections. This
    will go away later when RCU is used for server connections also.

    Signed-off-by: David Howells

    David Howells
     
  • rxrpc_connection_lock shouldn't be accessed as a BH-excluding lock. It's
    only accessed in a few places and none of those are in BH-context.

    rxrpc_transport::conn_lock, however, *is* a BH-excluding lock and should be
    accessed so consistently.

    Signed-off-by: David Howells

    David Howells
     
  • Pass a pointer to struct sk_buff rather than struct rxrpc_host_header to
    functions so that they can in the future get at transport protocol parameters
    rather than just RxRPC parameters.

    Signed-off-by: David Howells

    David Howells
     
  • "Exclusive connections" are meant to be used for a single client call and
    then scrapped. The idea is to limit the use of the negotiated security
    context. The current code, however, isn't doing this: it is instead
    restricting the socket to a single virtual connection and doing all the
    calls over that.

    This is changed such that the socket no longer maintains a special virtual
    connection over which it will do all the calls, but rather gets a new one
    each time a new exclusive call is made.

    Further, using a socket option for this is a poor choice. It should be
    done on sendmsg with a control message marker instead so that calls can be
    marked exclusive individually. To that end, add RXRPC_EXCLUSIVE_CALL
    which, if passed to sendmsg() as a control message element, will cause the
    call to be done on an single-use connection.

    The socket option (RXRPC_EXCLUSIVE_CONNECTION) still exists and, if set,
    will override any lack of RXRPC_EXCLUSIVE_CALL being specified so that
    programs using the setsockopt() will appear to work the same.

    Signed-off-by: David Howells

    David Howells
     
  • Define and use a structure to hold connection parameters. This makes it
    easier to pass multiple connection parameters around.

    Define and use a structure to hold protocol information used to hash a
    connection for lookup on incoming packet. Most of these fields will be
    disposed of eventually, including the duplicate local pointer.

    Whilst we're at it rename "proto" to "family" when referring to a protocol
    family.

    Signed-off-by: David Howells

    David Howells
     

13 Jun, 2016

1 commit

  • Rename files matching net/rxrpc/ar-*.c to get rid of the "ar-" prefix.
    This will aid splitting those files by making easier to come up with new
    names.

    Note that the not all files are simply renamed from ar-X.c to X.c. The
    following exceptions are made:

    (*) ar-call.c -> call_object.c
    ar-ack.c -> call_event.c

    call_object.c is going to contain the core of the call object
    handling. Call event handling is all going to be in call_event.c.

    (*) ar-accept.c -> call_accept.c

    Incoming call handling is going to be here.

    (*) ar-connection.c -> conn_object.c
    ar-connevent.c -> conn_event.c

    The former file is going to have the basic connection object handling,
    but there will likely be some differentiation between client
    connections and service connections in additional files later. The
    latter file will have all the connection-level event handling.

    (*) ar-local.c -> local_object.c

    This will have the local endpoint object handling code. The local
    endpoint event handling code will later be split out into
    local_event.c.

    (*) ar-peer.c -> peer_object.c

    This will have the peer endpoint object handling code. Peer event
    handling code will be placed in peer_event.c (for the moment, there is
    none).

    (*) ar-error.c -> peer_event.c

    This will become the peer event handling code, though for the moment
    it's actually driven from the local endpoint's perspective.

    Note that I haven't renamed ar-transport.c to transport_object.c as the
    intention is to delete it when the rxrpc_transport struct is excised.

    The only file that actually has its contents changed is net/rxrpc/Makefile.

    net/rxrpc/ar-internal.h will need its section marker comments updating, but
    I'll do that in a separate patch to make it easier for git to follow the
    history across the rename. I may also want to rename ar-internal.h at some
    point - but that would mean updating all the #includes and I'd rather do
    that in a separate step.

    Signed-off-by: David Howells <dhowells@redhat.com.

    David Howells