651350d10f
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>
221 lines
8.6 KiB
C
221 lines
8.6 KiB
C
/* packet.h: Rx packet layout and definitions
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*
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* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _LINUX_RXRPC_PACKET_H
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#define _LINUX_RXRPC_PACKET_H
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#include <rxrpc/types.h>
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#define RXRPC_IPUDP_SIZE 28
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extern size_t RXRPC_MAX_PACKET_SIZE;
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#define RXRPC_MAX_PACKET_DATA_SIZE (RXRPC_MAX_PACKET_SIZE - sizeof(struct rxrpc_header))
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#define RXRPC_LOCAL_PACKET_SIZE RXRPC_MAX_PACKET_SIZE
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#define RXRPC_REMOTE_PACKET_SIZE (576 - RXRPC_IPUDP_SIZE)
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/*****************************************************************************/
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/*
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* on-the-wire Rx packet header
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* - all multibyte fields should be in network byte order
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*/
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struct rxrpc_header
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{
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__be32 epoch; /* client boot timestamp */
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__be32 cid; /* connection and channel ID */
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#define RXRPC_MAXCALLS 4 /* max active calls per conn */
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#define RXRPC_CHANNELMASK (RXRPC_MAXCALLS-1) /* mask for channel ID */
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#define RXRPC_CIDMASK (~RXRPC_CHANNELMASK) /* mask for connection ID */
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#define RXRPC_CIDSHIFT ilog2(RXRPC_MAXCALLS) /* shift for connection ID */
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#define RXRPC_CID_INC (1 << RXRPC_CIDSHIFT) /* connection ID increment */
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__be32 callNumber; /* call ID (0 for connection-level packets) */
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#define RXRPC_PROCESS_MAXCALLS (1<<2) /* maximum number of active calls per conn (power of 2) */
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__be32 seq; /* sequence number of pkt in call stream */
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__be32 serial; /* serial number of pkt sent to network */
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uint8_t type; /* packet type */
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#define RXRPC_PACKET_TYPE_DATA 1 /* data */
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#define RXRPC_PACKET_TYPE_ACK 2 /* ACK */
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#define RXRPC_PACKET_TYPE_BUSY 3 /* call reject */
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#define RXRPC_PACKET_TYPE_ABORT 4 /* call/connection abort */
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#define RXRPC_PACKET_TYPE_ACKALL 5 /* ACK all outstanding packets on call */
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#define RXRPC_PACKET_TYPE_CHALLENGE 6 /* connection security challenge (SRVR->CLNT) */
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#define RXRPC_PACKET_TYPE_RESPONSE 7 /* connection secutity response (CLNT->SRVR) */
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#define RXRPC_PACKET_TYPE_DEBUG 8 /* debug info request */
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#define RXRPC_N_PACKET_TYPES 9 /* number of packet types (incl type 0) */
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uint8_t flags; /* packet flags */
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#define RXRPC_CLIENT_INITIATED 0x01 /* signifies a packet generated by a client */
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#define RXRPC_REQUEST_ACK 0x02 /* request an unconditional ACK of this packet */
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#define RXRPC_LAST_PACKET 0x04 /* the last packet from this side for this call */
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#define RXRPC_MORE_PACKETS 0x08 /* more packets to come */
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#define RXRPC_JUMBO_PACKET 0x20 /* [DATA] this is a jumbo packet */
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#define RXRPC_SLOW_START_OK 0x20 /* [ACK] slow start supported */
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uint8_t userStatus; /* app-layer defined status */
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uint8_t securityIndex; /* security protocol ID */
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union {
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__be16 _rsvd; /* reserved */
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__be16 cksum; /* kerberos security checksum */
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};
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__be16 serviceId; /* service ID */
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} __attribute__((packed));
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#define __rxrpc_header_off(X) offsetof(struct rxrpc_header,X)
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extern const char *rxrpc_pkts[];
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/*****************************************************************************/
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/*
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* jumbo packet secondary header
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* - can be mapped to read header by:
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* - new_serial = serial + 1
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* - new_seq = seq + 1
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* - new_flags = j_flags
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* - new__rsvd = j__rsvd
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* - duplicating all other fields
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*/
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struct rxrpc_jumbo_header
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{
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uint8_t flags; /* packet flags (as per rxrpc_header) */
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uint8_t pad;
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__be16 _rsvd; /* reserved (used by kerberos security as cksum) */
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};
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#define RXRPC_JUMBO_DATALEN 1412 /* non-terminal jumbo packet data length */
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/*****************************************************************************/
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/*
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* on-the-wire Rx ACK packet data payload
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* - all multibyte fields should be in network byte order
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*/
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struct rxrpc_ackpacket
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{
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__be16 bufferSpace; /* number of packet buffers available */
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__be16 maxSkew; /* diff between serno being ACK'd and highest serial no
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* received */
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__be32 firstPacket; /* sequence no of first ACK'd packet in attached list */
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__be32 previousPacket; /* sequence no of previous packet received */
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__be32 serial; /* serial no of packet that prompted this ACK */
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uint8_t reason; /* reason for ACK */
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#define RXRPC_ACK_REQUESTED 1 /* ACK was requested on packet */
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#define RXRPC_ACK_DUPLICATE 2 /* duplicate packet received */
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#define RXRPC_ACK_OUT_OF_SEQUENCE 3 /* out of sequence packet received */
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#define RXRPC_ACK_EXCEEDS_WINDOW 4 /* packet received beyond end of ACK window */
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#define RXRPC_ACK_NOSPACE 5 /* packet discarded due to lack of buffer space */
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#define RXRPC_ACK_PING 6 /* keep alive ACK */
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#define RXRPC_ACK_PING_RESPONSE 7 /* response to RXRPC_ACK_PING */
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#define RXRPC_ACK_DELAY 8 /* nothing happened since received packet */
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#define RXRPC_ACK_IDLE 9 /* ACK due to fully received ACK window */
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uint8_t nAcks; /* number of ACKs */
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#define RXRPC_MAXACKS 255
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uint8_t acks[0]; /* list of ACK/NAKs */
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#define RXRPC_ACK_TYPE_NACK 0
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#define RXRPC_ACK_TYPE_ACK 1
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} __attribute__((packed));
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/*
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* ACK packets can have a further piece of information tagged on the end
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*/
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struct rxrpc_ackinfo {
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__be32 rxMTU; /* maximum Rx MTU size (bytes) [AFS 3.3] */
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__be32 maxMTU; /* maximum interface MTU size (bytes) [AFS 3.3] */
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__be32 rwind; /* Rx window size (packets) [AFS 3.4] */
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__be32 jumbo_max; /* max packets to stick into a jumbo packet [AFS 3.5] */
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};
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/*****************************************************************************/
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/*
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* Kerberos security type-2 challenge packet
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*/
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struct rxkad_challenge {
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__be32 version; /* version of this challenge type */
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__be32 nonce; /* encrypted random number */
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__be32 min_level; /* minimum security level */
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__be32 __padding; /* padding to 8-byte boundary */
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} __attribute__((packed));
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/*****************************************************************************/
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/*
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* Kerberos security type-2 response packet
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*/
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struct rxkad_response {
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__be32 version; /* version of this reponse type */
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__be32 __pad;
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/* encrypted bit of the response */
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struct {
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__be32 epoch; /* current epoch */
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__be32 cid; /* parent connection ID */
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__be32 checksum; /* checksum */
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__be32 securityIndex; /* security type */
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__be32 call_id[4]; /* encrypted call IDs */
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__be32 inc_nonce; /* challenge nonce + 1 */
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__be32 level; /* desired level */
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} encrypted;
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__be32 kvno; /* Kerberos key version number */
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__be32 ticket_len; /* Kerberos ticket length */
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} __attribute__((packed));
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/*****************************************************************************/
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/*
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* RxRPC-level abort codes
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*/
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#define RX_CALL_DEAD -1 /* call/conn has been inactive and is shut down */
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#define RX_INVALID_OPERATION -2 /* invalid operation requested / attempted */
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#define RX_CALL_TIMEOUT -3 /* call timeout exceeded */
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#define RX_EOF -4 /* unexpected end of data on read op */
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#define RX_PROTOCOL_ERROR -5 /* low-level protocol error */
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#define RX_USER_ABORT -6 /* generic user abort */
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#define RX_ADDRINUSE -7 /* UDP port in use */
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#define RX_DEBUGI_BADTYPE -8 /* bad debugging packet type */
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/*
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* (un)marshalling abort codes (rxgen)
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*/
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#define RXGEN_CC_MARSHAL -450
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#define RXGEN_CC_UNMARSHAL -451
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#define RXGEN_SS_MARSHAL -452
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#define RXGEN_SS_UNMARSHAL -453
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#define RXGEN_DECODE -454
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#define RXGEN_OPCODE -455
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#define RXGEN_SS_XDRFREE -456
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#define RXGEN_CC_XDRFREE -457
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/*
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* Rx kerberos security abort codes
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* - unfortunately we have no generalised security abort codes to say things
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* like "unsupported security", so we have to use these instead and hope the
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* other side understands
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*/
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#define RXKADINCONSISTENCY 19270400 /* security module structure inconsistent */
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#define RXKADPACKETSHORT 19270401 /* packet too short for security challenge */
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#define RXKADLEVELFAIL 19270402 /* security level negotiation failed */
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#define RXKADTICKETLEN 19270403 /* ticket length too short or too long */
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#define RXKADOUTOFSEQUENCE 19270404 /* packet had bad sequence number */
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#define RXKADNOAUTH 19270405 /* caller not authorised */
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#define RXKADBADKEY 19270406 /* illegal key: bad parity or weak */
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#define RXKADBADTICKET 19270407 /* security object was passed a bad ticket */
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#define RXKADUNKNOWNKEY 19270408 /* ticket contained unknown key version number */
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#define RXKADEXPIRED 19270409 /* authentication expired */
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#define RXKADSEALEDINCON 19270410 /* sealed data inconsistent */
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#define RXKADDATALEN 19270411 /* user data too long */
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#define RXKADILLEGALLEVEL 19270412 /* caller not authorised to use encrypted conns */
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#endif /* _LINUX_RXRPC_PACKET_H */
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