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linux/net/rxrpc/ar-ack.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

1251 lines
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/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
*
* 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/circ_buf.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
static unsigned rxrpc_ack_defer = 1;
static const char *rxrpc_acks[] = {
"---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY", "IDL",
"-?-"
};
static const s8 rxrpc_ack_priority[] = {
[0] = 0,
[RXRPC_ACK_DELAY] = 1,
[RXRPC_ACK_REQUESTED] = 2,
[RXRPC_ACK_IDLE] = 3,
[RXRPC_ACK_PING_RESPONSE] = 4,
[RXRPC_ACK_DUPLICATE] = 5,
[RXRPC_ACK_OUT_OF_SEQUENCE] = 6,
[RXRPC_ACK_EXCEEDS_WINDOW] = 7,
[RXRPC_ACK_NOSPACE] = 8,
};
/*
* propose an ACK be sent
*/
void __rxrpc_propose_ACK(struct rxrpc_call *call, uint8_t ack_reason,
__be32 serial, bool immediate)
{
unsigned long expiry;
s8 prior = rxrpc_ack_priority[ack_reason];
ASSERTCMP(prior, >, 0);
_enter("{%d},%s,%%%x,%u",
call->debug_id, rxrpc_acks[ack_reason], ntohl(serial),
immediate);
if (prior < rxrpc_ack_priority[call->ackr_reason]) {
if (immediate)
goto cancel_timer;
return;
}
/* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
* numbers */
if (prior == rxrpc_ack_priority[call->ackr_reason]) {
if (prior <= 4)
call->ackr_serial = serial;
if (immediate)
goto cancel_timer;
return;
}
call->ackr_reason = ack_reason;
call->ackr_serial = serial;
switch (ack_reason) {
case RXRPC_ACK_DELAY:
_debug("run delay timer");
call->ack_timer.expires = jiffies + rxrpc_ack_timeout * HZ;
add_timer(&call->ack_timer);
return;
case RXRPC_ACK_IDLE:
if (!immediate) {
_debug("run defer timer");
expiry = 1;
goto run_timer;
}
goto cancel_timer;
case RXRPC_ACK_REQUESTED:
if (!rxrpc_ack_defer)
goto cancel_timer;
if (!immediate || serial == cpu_to_be32(1)) {
_debug("run defer timer");
expiry = rxrpc_ack_defer;
goto run_timer;
}
default:
_debug("immediate ACK");
goto cancel_timer;
}
run_timer:
expiry += jiffies;
if (!timer_pending(&call->ack_timer) ||
time_after(call->ack_timer.expires, expiry))
mod_timer(&call->ack_timer, expiry);
return;
cancel_timer:
_debug("cancel timer %%%u", ntohl(serial));
try_to_del_timer_sync(&call->ack_timer);
read_lock_bh(&call->state_lock);
if (call->state <= RXRPC_CALL_COMPLETE &&
!test_and_set_bit(RXRPC_CALL_ACK, &call->events))
rxrpc_queue_call(call);
read_unlock_bh(&call->state_lock);
}
/*
* propose an ACK be sent, locking the call structure
*/
void rxrpc_propose_ACK(struct rxrpc_call *call, uint8_t ack_reason,
__be32 serial, bool immediate)
{
s8 prior = rxrpc_ack_priority[ack_reason];
if (prior > rxrpc_ack_priority[call->ackr_reason]) {
spin_lock_bh(&call->lock);
__rxrpc_propose_ACK(call, ack_reason, serial, immediate);
spin_unlock_bh(&call->lock);
}
}
/*
* set the resend timer
*/
static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
unsigned long resend_at)
{
read_lock_bh(&call->state_lock);
if (call->state >= RXRPC_CALL_COMPLETE)
resend = 0;
if (resend & 1) {
_debug("SET RESEND");
set_bit(RXRPC_CALL_RESEND, &call->events);
}
if (resend & 2) {
_debug("MODIFY RESEND TIMER");
set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
mod_timer(&call->resend_timer, resend_at);
} else {
_debug("KILL RESEND TIMER");
del_timer_sync(&call->resend_timer);
clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
}
read_unlock_bh(&call->state_lock);
}
/*
* resend packets
*/
static void rxrpc_resend(struct rxrpc_call *call)
{
struct rxrpc_skb_priv *sp;
struct rxrpc_header *hdr;
struct sk_buff *txb;
unsigned long *p_txb, resend_at;
int loop, stop;
u8 resend;
_enter("{%d,%d,%d,%d},",
call->acks_hard, call->acks_unacked,
atomic_read(&call->sequence),
CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
stop = 0;
resend = 0;
resend_at = 0;
for (loop = call->acks_tail;
loop != call->acks_head || stop;
loop = (loop + 1) & (call->acks_winsz - 1)
) {
p_txb = call->acks_window + loop;
smp_read_barrier_depends();
if (*p_txb & 1)
continue;
txb = (struct sk_buff *) *p_txb;
sp = rxrpc_skb(txb);
if (sp->need_resend) {
sp->need_resend = 0;
/* each Tx packet has a new serial number */
sp->hdr.serial =
htonl(atomic_inc_return(&call->conn->serial));
hdr = (struct rxrpc_header *) txb->head;
hdr->serial = sp->hdr.serial;
_proto("Tx DATA %%%u { #%d }",
ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
stop = 0;
sp->resend_at = jiffies + 3;
} else {
sp->resend_at =
jiffies + rxrpc_resend_timeout * HZ;
}
}
if (time_after_eq(jiffies + 1, sp->resend_at)) {
sp->need_resend = 1;
resend |= 1;
} else if (resend & 2) {
if (time_before(sp->resend_at, resend_at))
resend_at = sp->resend_at;
} else {
resend_at = sp->resend_at;
resend |= 2;
}
}
rxrpc_set_resend(call, resend, resend_at);
_leave("");
}
/*
* handle resend timer expiry
*/
static void rxrpc_resend_timer(struct rxrpc_call *call)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *txb;
unsigned long *p_txb, resend_at;
int loop;
u8 resend;
_enter("%d,%d,%d",
call->acks_tail, call->acks_unacked, call->acks_head);
resend = 0;
resend_at = 0;
for (loop = call->acks_unacked;
loop != call->acks_head;
loop = (loop + 1) & (call->acks_winsz - 1)
) {
p_txb = call->acks_window + loop;
smp_read_barrier_depends();
txb = (struct sk_buff *) (*p_txb & ~1);
sp = rxrpc_skb(txb);
ASSERT(!(*p_txb & 1));
if (sp->need_resend) {
;
} else if (time_after_eq(jiffies + 1, sp->resend_at)) {
sp->need_resend = 1;
resend |= 1;
} else if (resend & 2) {
if (time_before(sp->resend_at, resend_at))
resend_at = sp->resend_at;
} else {
resend_at = sp->resend_at;
resend |= 2;
}
}
rxrpc_set_resend(call, resend, resend_at);
_leave("");
}
/*
* process soft ACKs of our transmitted packets
* - these indicate packets the peer has or has not received, but hasn't yet
* given to the consumer, and so can still be discarded and re-requested
*/
static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
struct rxrpc_ackpacket *ack,
struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *txb;
unsigned long *p_txb, resend_at;
int loop;
u8 sacks[RXRPC_MAXACKS], resend;
_enter("{%d,%d},{%d},",
call->acks_hard,
CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
ack->nAcks);
if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
goto protocol_error;
resend = 0;
resend_at = 0;
for (loop = 0; loop < ack->nAcks; loop++) {
p_txb = call->acks_window;
p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
smp_read_barrier_depends();
txb = (struct sk_buff *) (*p_txb & ~1);
sp = rxrpc_skb(txb);
switch (sacks[loop]) {
case RXRPC_ACK_TYPE_ACK:
sp->need_resend = 0;
*p_txb |= 1;
break;
case RXRPC_ACK_TYPE_NACK:
sp->need_resend = 1;
*p_txb &= ~1;
resend = 1;
break;
default:
_debug("Unsupported ACK type %d", sacks[loop]);
goto protocol_error;
}
}
smp_mb();
call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
/* anything not explicitly ACK'd is implicitly NACK'd, but may just not
* have been received or processed yet by the far end */
for (loop = call->acks_unacked;
loop != call->acks_head;
loop = (loop + 1) & (call->acks_winsz - 1)
) {
p_txb = call->acks_window + loop;
smp_read_barrier_depends();
txb = (struct sk_buff *) (*p_txb & ~1);
sp = rxrpc_skb(txb);
if (*p_txb & 1) {
/* packet must have been discarded */
sp->need_resend = 1;
*p_txb &= ~1;
resend |= 1;
} else if (sp->need_resend) {
;
} else if (time_after_eq(jiffies + 1, sp->resend_at)) {
sp->need_resend = 1;
resend |= 1;
} else if (resend & 2) {
if (time_before(sp->resend_at, resend_at))
resend_at = sp->resend_at;
} else {
resend_at = sp->resend_at;
resend |= 2;
}
}
rxrpc_set_resend(call, resend, resend_at);
_leave(" = 0");
return 0;
protocol_error:
_leave(" = -EPROTO");
return -EPROTO;
}
/*
* discard hard-ACK'd packets from the Tx window
*/
static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
{
struct rxrpc_skb_priv *sp;
unsigned long _skb;
int tail = call->acks_tail, old_tail;
int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
_enter("{%u,%u},%u", call->acks_hard, win, hard);
ASSERTCMP(hard - call->acks_hard, <=, win);
while (call->acks_hard < hard) {
smp_read_barrier_depends();
_skb = call->acks_window[tail] & ~1;
sp = rxrpc_skb((struct sk_buff *) _skb);
rxrpc_free_skb((struct sk_buff *) _skb);
old_tail = tail;
tail = (tail + 1) & (call->acks_winsz - 1);
call->acks_tail = tail;
if (call->acks_unacked == old_tail)
call->acks_unacked = tail;
call->acks_hard++;
}
wake_up(&call->tx_waitq);
}
/*
* clear the Tx window in the event of a failure
*/
static void rxrpc_clear_tx_window(struct rxrpc_call *call)
{
rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
}
/*
* drain the out of sequence received packet queue into the packet Rx queue
*/
static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
bool terminal;
int ret;
_enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
spin_lock_bh(&call->lock);
ret = -ECONNRESET;
if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
goto socket_unavailable;
skb = skb_dequeue(&call->rx_oos_queue);
if (skb) {
sp = rxrpc_skb(skb);
_debug("drain OOS packet %d [%d]",
ntohl(sp->hdr.seq), call->rx_first_oos);
if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
skb_queue_head(&call->rx_oos_queue, skb);
call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
_debug("requeue %p {%u}", skb, call->rx_first_oos);
} else {
skb->mark = RXRPC_SKB_MARK_DATA;
terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
!(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
BUG_ON(ret < 0);
_debug("drain #%u", call->rx_data_post);
call->rx_data_post++;
/* find out what the next packet is */
skb = skb_peek(&call->rx_oos_queue);
if (skb)
call->rx_first_oos =
ntohl(rxrpc_skb(skb)->hdr.seq);
else
call->rx_first_oos = 0;
_debug("peek %p {%u}", skb, call->rx_first_oos);
}
}
ret = 0;
socket_unavailable:
spin_unlock_bh(&call->lock);
_leave(" = %d", ret);
return ret;
}
/*
* insert an out of sequence packet into the buffer
*/
static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp, *psp;
struct sk_buff *p;
u32 seq;
sp = rxrpc_skb(skb);
seq = ntohl(sp->hdr.seq);
_enter(",,{%u}", seq);
skb->destructor = rxrpc_packet_destructor;
ASSERTCMP(sp->call, ==, NULL);
sp->call = call;
rxrpc_get_call(call);
/* insert into the buffer in sequence order */
spin_lock_bh(&call->lock);
skb_queue_walk(&call->rx_oos_queue, p) {
psp = rxrpc_skb(p);
if (ntohl(psp->hdr.seq) > seq) {
_debug("insert oos #%u before #%u",
seq, ntohl(psp->hdr.seq));
skb_insert(p, skb, &call->rx_oos_queue);
goto inserted;
}
}
_debug("append oos #%u", seq);
skb_queue_tail(&call->rx_oos_queue, skb);
inserted:
/* we might now have a new front to the queue */
if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
call->rx_first_oos = seq;
read_lock(&call->state_lock);
if (call->state < RXRPC_CALL_COMPLETE &&
call->rx_data_post == call->rx_first_oos) {
_debug("drain rx oos now");
set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
}
read_unlock(&call->state_lock);
spin_unlock_bh(&call->lock);
_leave(" [stored #%u]", call->rx_first_oos);
}
/*
* clear the Tx window on final ACK reception
*/
static void rxrpc_zap_tx_window(struct rxrpc_call *call)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
unsigned long _skb, *acks_window;
uint8_t winsz = call->acks_winsz;
int tail;
acks_window = call->acks_window;
call->acks_window = NULL;
while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
tail = call->acks_tail;
smp_read_barrier_depends();
_skb = acks_window[tail] & ~1;
smp_mb();
call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
skb = (struct sk_buff *) _skb;
sp = rxrpc_skb(skb);
_debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
rxrpc_free_skb(skb);
}
kfree(acks_window);
}
/*
* process packets in the reception queue
*/
static int rxrpc_process_rx_queue(struct rxrpc_call *call,
u32 *_abort_code)
{
struct rxrpc_ackpacket ack;
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
bool post_ACK;
int latest;
u32 hard, tx;
_enter("");
process_further:
skb = skb_dequeue(&call->rx_queue);
if (!skb)
return -EAGAIN;
_net("deferred skb %p", skb);
sp = rxrpc_skb(skb);
_debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
post_ACK = false;
switch (sp->hdr.type) {
/* data packets that wind up here have been received out of
* order, need security processing or are jumbo packets */
case RXRPC_PACKET_TYPE_DATA:
_proto("OOSQ DATA %%%u { #%u }",
ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
/* secured packets must be verified and possibly decrypted */
if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
goto protocol_error;
rxrpc_insert_oos_packet(call, skb);
goto process_further;
/* partial ACK to process */
case RXRPC_PACKET_TYPE_ACK:
if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
_debug("extraction failure");
goto protocol_error;
}
if (!skb_pull(skb, sizeof(ack)))
BUG();
latest = ntohl(sp->hdr.serial);
hard = ntohl(ack.firstPacket);
tx = atomic_read(&call->sequence);
_proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
latest,
ntohs(ack.maxSkew),
hard,
ntohl(ack.previousPacket),
ntohl(ack.serial),
rxrpc_acks[ack.reason],
ack.nAcks);
if (ack.reason == RXRPC_ACK_PING) {
_proto("Rx ACK %%%u PING Request", latest);
rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
sp->hdr.serial, true);
}
/* discard any out-of-order or duplicate ACKs */
if (latest - call->acks_latest <= 0) {
_debug("discard ACK %d <= %d",
latest, call->acks_latest);
goto discard;
}
call->acks_latest = latest;
if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
goto discard;
_debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
if (hard > 0) {
if (hard - 1 > tx) {
_debug("hard-ACK'd packet %d not transmitted"
" (%d top)",
hard - 1, tx);
goto protocol_error;
}
if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
hard > tx)
goto all_acked;
smp_rmb();
rxrpc_rotate_tx_window(call, hard - 1);
}
if (ack.nAcks > 0) {
if (hard - 1 + ack.nAcks > tx) {
_debug("soft-ACK'd packet %d+%d not"
" transmitted (%d top)",
hard - 1, ack.nAcks, tx);
goto protocol_error;
}
if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
goto protocol_error;
}
goto discard;
/* complete ACK to process */
case RXRPC_PACKET_TYPE_ACKALL:
goto all_acked;
/* abort and busy are handled elsewhere */
case RXRPC_PACKET_TYPE_BUSY:
case RXRPC_PACKET_TYPE_ABORT:
BUG();
/* connection level events - also handled elsewhere */
case RXRPC_PACKET_TYPE_CHALLENGE:
case RXRPC_PACKET_TYPE_RESPONSE:
case RXRPC_PACKET_TYPE_DEBUG:
BUG();
}
/* if we've had a hard ACK that covers all the packets we've sent, then
* that ends that phase of the operation */
all_acked:
write_lock_bh(&call->state_lock);
_debug("ack all %d", call->state);
switch (call->state) {
case RXRPC_CALL_CLIENT_AWAIT_REPLY:
call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
break;
case RXRPC_CALL_SERVER_AWAIT_ACK:
_debug("srv complete");
call->state = RXRPC_CALL_COMPLETE;
post_ACK = true;
break;
case RXRPC_CALL_CLIENT_SEND_REQUEST:
case RXRPC_CALL_SERVER_RECV_REQUEST:
goto protocol_error_unlock; /* can't occur yet */
default:
write_unlock_bh(&call->state_lock);
goto discard; /* assume packet left over from earlier phase */
}
write_unlock_bh(&call->state_lock);
/* if all the packets we sent are hard-ACK'd, then we can discard
* whatever we've got left */
_debug("clear Tx %d",
CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
del_timer_sync(&call->resend_timer);
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
if (call->acks_window)
rxrpc_zap_tx_window(call);
if (post_ACK) {
/* post the final ACK message for userspace to pick up */
_debug("post ACK");
skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
sp->call = call;
rxrpc_get_call(call);
spin_lock_bh(&call->lock);
if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
BUG();
spin_unlock_bh(&call->lock);
goto process_further;
}
discard:
rxrpc_free_skb(skb);
goto process_further;
protocol_error_unlock:
write_unlock_bh(&call->state_lock);
protocol_error:
rxrpc_free_skb(skb);
_leave(" = -EPROTO");
return -EPROTO;
}
/*
* post a message to the socket Rx queue for recvmsg() to pick up
*/
static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
bool fatal)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
int ret;
_enter("{%d,%lx},%u,%u,%d",
call->debug_id, call->flags, mark, error, fatal);
/* remove timers and things for fatal messages */
if (fatal) {
del_timer_sync(&call->resend_timer);
del_timer_sync(&call->ack_timer);
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
}
if (mark != RXRPC_SKB_MARK_NEW_CALL &&
!test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
_leave("[no userid]");
return 0;
}
if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
skb = alloc_skb(0, GFP_NOFS);
if (!skb)
return -ENOMEM;
rxrpc_new_skb(skb);
skb->mark = mark;
sp = rxrpc_skb(skb);
memset(sp, 0, sizeof(*sp));
sp->error = error;
sp->call = call;
rxrpc_get_call(call);
spin_lock_bh(&call->lock);
ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
spin_unlock_bh(&call->lock);
if (ret < 0)
BUG();
}
return 0;
}
/*
* handle background processing of incoming call packets and ACK / abort
* generation
*/
void rxrpc_process_call(struct work_struct *work)
{
struct rxrpc_call *call =
container_of(work, struct rxrpc_call, processor);
struct rxrpc_ackpacket ack;
struct rxrpc_ackinfo ackinfo;
struct rxrpc_header hdr;
struct msghdr msg;
struct kvec iov[5];
unsigned long bits;
__be32 data;
size_t len;
int genbit, loop, nbit, ioc, ret;
u32 abort_code = RX_PROTOCOL_ERROR;
u8 *acks = NULL;
//printk("\n--------------------\n");
_enter("{%d,%s,%lx} [%lu]",
call->debug_id, rxrpc_call_states[call->state], call->events,
(jiffies - call->creation_jif) / (HZ / 10));
if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
_debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
return;
}
/* there's a good chance we're going to have to send a message, so set
* one up in advance */
msg.msg_name = &call->conn->trans->peer->srx.transport.sin;
msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
hdr.epoch = call->conn->epoch;
hdr.cid = call->cid;
hdr.callNumber = call->call_id;
hdr.seq = 0;
hdr.type = RXRPC_PACKET_TYPE_ACK;
hdr.flags = call->conn->out_clientflag;
hdr.userStatus = 0;
hdr.securityIndex = call->conn->security_ix;
hdr._rsvd = 0;
hdr.serviceId = call->conn->service_id;
memset(iov, 0, sizeof(iov));
iov[0].iov_base = &hdr;
iov[0].iov_len = sizeof(hdr);
/* deal with events of a final nature */
if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
rxrpc_release_call(call);
clear_bit(RXRPC_CALL_RELEASE, &call->events);
}
if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
int error;
clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
clear_bit(RXRPC_CALL_ABORT, &call->events);
error = call->conn->trans->peer->net_error;
_debug("post net error %d", error);
if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
error, true) < 0)
goto no_mem;
clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
goto kill_ACKs;
}
if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
clear_bit(RXRPC_CALL_ABORT, &call->events);
_debug("post conn abort");
if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
call->conn->error, true) < 0)
goto no_mem;
clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
goto kill_ACKs;
}
if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
hdr.type = RXRPC_PACKET_TYPE_BUSY;
genbit = RXRPC_CALL_REJECT_BUSY;
goto send_message;
}
if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
ECONNABORTED, true) < 0)
goto no_mem;
hdr.type = RXRPC_PACKET_TYPE_ABORT;
data = htonl(call->abort_code);
iov[1].iov_base = &data;
iov[1].iov_len = sizeof(data);
genbit = RXRPC_CALL_ABORT;
goto send_message;
}
if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
hdr.type = RXRPC_PACKET_TYPE_ACKALL;
genbit = RXRPC_CALL_ACK_FINAL;
goto send_message;
}
if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
(1 << RXRPC_CALL_RCVD_ABORT))
) {
u32 mark;
if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
mark = RXRPC_SKB_MARK_REMOTE_ABORT;
else
mark = RXRPC_SKB_MARK_BUSY;
_debug("post abort/busy");
rxrpc_clear_tx_window(call);
if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
goto no_mem;
clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
goto kill_ACKs;
}
if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
_debug("do implicit ackall");
rxrpc_clear_tx_window(call);
}
if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
write_lock_bh(&call->state_lock);
if (call->state <= RXRPC_CALL_COMPLETE) {
call->state = RXRPC_CALL_LOCALLY_ABORTED;
call->abort_code = RX_CALL_TIMEOUT;
set_bit(RXRPC_CALL_ABORT, &call->events);
}
write_unlock_bh(&call->state_lock);
_debug("post timeout");
if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
ETIME, true) < 0)
goto no_mem;
clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
goto kill_ACKs;
}
/* deal with assorted inbound messages */
if (!skb_queue_empty(&call->rx_queue)) {
switch (rxrpc_process_rx_queue(call, &abort_code)) {
case 0:
case -EAGAIN:
break;
case -ENOMEM:
goto no_mem;
case -EKEYEXPIRED:
case -EKEYREJECTED:
case -EPROTO:
rxrpc_abort_call(call, abort_code);
goto kill_ACKs;
}
}
/* handle resending */
if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
rxrpc_resend_timer(call);
if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
rxrpc_resend(call);
/* consider sending an ordinary ACK */
if (test_bit(RXRPC_CALL_ACK, &call->events)) {
__be32 pad;
_debug("send ACK: window: %d - %d { %lx }",
call->rx_data_eaten, call->ackr_win_top,
call->ackr_window[0]);
if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
/* ACK by sending reply DATA packet in this state */
clear_bit(RXRPC_CALL_ACK, &call->events);
goto maybe_reschedule;
}
genbit = RXRPC_CALL_ACK;
acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
GFP_NOFS);
if (!acks)
goto no_mem;
//hdr.flags = RXRPC_SLOW_START_OK;
ack.bufferSpace = htons(8);
ack.maxSkew = 0;
ack.serial = 0;
ack.reason = 0;
ackinfo.rxMTU = htonl(5692);
// ackinfo.rxMTU = htonl(call->conn->trans->peer->maxdata);
ackinfo.maxMTU = htonl(call->conn->trans->peer->maxdata);
ackinfo.rwind = htonl(32);
ackinfo.jumbo_max = htonl(4);
spin_lock_bh(&call->lock);
ack.reason = call->ackr_reason;
ack.serial = call->ackr_serial;
ack.previousPacket = call->ackr_prev_seq;
ack.firstPacket = htonl(call->rx_data_eaten + 1);
ack.nAcks = 0;
for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
nbit = loop * BITS_PER_LONG;
for (bits = call->ackr_window[loop]; bits; bits >>= 1
) {
_debug("- l=%d n=%d b=%lx", loop, nbit, bits);
if (bits & 1) {
acks[nbit] = RXRPC_ACK_TYPE_ACK;
ack.nAcks = nbit + 1;
}
nbit++;
}
}
call->ackr_reason = 0;
spin_unlock_bh(&call->lock);
pad = 0;
iov[1].iov_base = &ack;
iov[1].iov_len = sizeof(ack);
iov[2].iov_base = acks;
iov[2].iov_len = ack.nAcks;
iov[3].iov_base = &pad;
iov[3].iov_len = 3;
iov[4].iov_base = &ackinfo;
iov[4].iov_len = sizeof(ackinfo);
switch (ack.reason) {
case RXRPC_ACK_REQUESTED:
case RXRPC_ACK_DUPLICATE:
case RXRPC_ACK_OUT_OF_SEQUENCE:
case RXRPC_ACK_EXCEEDS_WINDOW:
case RXRPC_ACK_NOSPACE:
case RXRPC_ACK_PING:
case RXRPC_ACK_PING_RESPONSE:
goto send_ACK_with_skew;
case RXRPC_ACK_DELAY:
case RXRPC_ACK_IDLE:
goto send_ACK;
}
}
/* handle completion of security negotiations on an incoming
* connection */
if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
_debug("secured");
spin_lock_bh(&call->lock);
if (call->state == RXRPC_CALL_SERVER_SECURING) {
_debug("securing");
write_lock(&call->conn->lock);
if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
!test_bit(RXRPC_CALL_RELEASE, &call->events)) {
_debug("not released");
call->state = RXRPC_CALL_SERVER_ACCEPTING;
list_move_tail(&call->accept_link,
&call->socket->acceptq);
}
write_unlock(&call->conn->lock);
read_lock(&call->state_lock);
if (call->state < RXRPC_CALL_COMPLETE)
set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
read_unlock(&call->state_lock);
}
spin_unlock_bh(&call->lock);
if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
goto maybe_reschedule;
}
/* post a notification of an acceptable connection to the app */
if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
_debug("post accept");
if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
0, false) < 0)
goto no_mem;
clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
goto maybe_reschedule;
}
/* handle incoming call acceptance */
if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
_debug("accepted");
ASSERTCMP(call->rx_data_post, ==, 0);
call->rx_data_post = 1;
read_lock_bh(&call->state_lock);
if (call->state < RXRPC_CALL_COMPLETE)
set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
read_unlock_bh(&call->state_lock);
}
/* drain the out of sequence received packet queue into the packet Rx
* queue */
if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
while (call->rx_data_post == call->rx_first_oos)
if (rxrpc_drain_rx_oos_queue(call) < 0)
break;
goto maybe_reschedule;
}
/* other events may have been raised since we started checking */
goto maybe_reschedule;
send_ACK_with_skew:
ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
ntohl(ack.serial));
send_ACK:
hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
_proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
ntohl(hdr.serial),
ntohs(ack.maxSkew),
ntohl(ack.firstPacket),
ntohl(ack.previousPacket),
ntohl(ack.serial),
rxrpc_acks[ack.reason],
ack.nAcks);
del_timer_sync(&call->ack_timer);
if (ack.nAcks > 0)
set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
goto send_message_2;
send_message:
_debug("send message");
hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
_proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
send_message_2:
len = iov[0].iov_len;
ioc = 1;
if (iov[4].iov_len) {
ioc = 5;
len += iov[4].iov_len;
len += iov[3].iov_len;
len += iov[2].iov_len;
len += iov[1].iov_len;
} else if (iov[3].iov_len) {
ioc = 4;
len += iov[3].iov_len;
len += iov[2].iov_len;
len += iov[1].iov_len;
} else if (iov[2].iov_len) {
ioc = 3;
len += iov[2].iov_len;
len += iov[1].iov_len;
} else if (iov[1].iov_len) {
ioc = 2;
len += iov[1].iov_len;
}
ret = kernel_sendmsg(call->conn->trans->local->socket,
&msg, iov, ioc, len);
if (ret < 0) {
_debug("sendmsg failed: %d", ret);
read_lock_bh(&call->state_lock);
if (call->state < RXRPC_CALL_DEAD)
rxrpc_queue_call(call);
read_unlock_bh(&call->state_lock);
goto error;
}
switch (genbit) {
case RXRPC_CALL_ABORT:
clear_bit(genbit, &call->events);
clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
goto kill_ACKs;
case RXRPC_CALL_ACK_FINAL:
write_lock_bh(&call->state_lock);
if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
call->state = RXRPC_CALL_COMPLETE;
write_unlock_bh(&call->state_lock);
goto kill_ACKs;
default:
clear_bit(genbit, &call->events);
switch (call->state) {
case RXRPC_CALL_CLIENT_AWAIT_REPLY:
case RXRPC_CALL_CLIENT_RECV_REPLY:
case RXRPC_CALL_SERVER_RECV_REQUEST:
case RXRPC_CALL_SERVER_ACK_REQUEST:
_debug("start ACK timer");
rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
call->ackr_serial, false);
default:
break;
}
goto maybe_reschedule;
}
kill_ACKs:
del_timer_sync(&call->ack_timer);
if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
rxrpc_put_call(call);
clear_bit(RXRPC_CALL_ACK, &call->events);
maybe_reschedule:
if (call->events || !skb_queue_empty(&call->rx_queue)) {
read_lock_bh(&call->state_lock);
if (call->state < RXRPC_CALL_DEAD)
rxrpc_queue_call(call);
read_unlock_bh(&call->state_lock);
}
/* don't leave aborted connections on the accept queue */
if (call->state >= RXRPC_CALL_COMPLETE &&
!list_empty(&call->accept_link)) {
_debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
call, call->events, call->flags,
ntohl(call->conn->cid));
read_lock_bh(&call->state_lock);
if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
!test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
rxrpc_queue_call(call);
read_unlock_bh(&call->state_lock);
}
error:
clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
kfree(acks);
/* because we don't want two CPUs both processing the work item for one
* call at the same time, we use a flag to note when it's busy; however
* this means there's a race between clearing the flag and setting the
* work pending bit and the work item being processed again */
if (call->events && !work_pending(&call->processor)) {
_debug("jumpstart %x", ntohl(call->conn->cid));
rxrpc_queue_call(call);
}
_leave("");
return;
no_mem:
_debug("out of memory");
goto maybe_reschedule;
}
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