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linux/net/rxrpc/ar-output.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

735 lines
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/* RxRPC packet transmission
*
* 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/net.h>
#include <linux/skbuff.h>
#include <linux/circ_buf.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
int rxrpc_resend_timeout = 4;
static int rxrpc_send_data(struct kiocb *iocb,
struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct msghdr *msg, size_t len);
/*
* extract control messages from the sendmsg() control buffer
*/
static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
unsigned long *user_call_ID,
enum rxrpc_command *command,
u32 *abort_code,
bool server)
{
struct cmsghdr *cmsg;
int len;
*command = RXRPC_CMD_SEND_DATA;
if (msg->msg_controllen == 0)
return -EINVAL;
for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
_debug("CMSG %d, %d, %d",
cmsg->cmsg_level, cmsg->cmsg_type, len);
if (cmsg->cmsg_level != SOL_RXRPC)
continue;
switch (cmsg->cmsg_type) {
case RXRPC_USER_CALL_ID:
if (msg->msg_flags & MSG_CMSG_COMPAT) {
if (len != sizeof(u32))
return -EINVAL;
*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
} else {
if (len != sizeof(unsigned long))
return -EINVAL;
*user_call_ID = *(unsigned long *)
CMSG_DATA(cmsg);
}
_debug("User Call ID %lx", *user_call_ID);
break;
case RXRPC_ABORT:
if (*command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
*command = RXRPC_CMD_SEND_ABORT;
if (len != sizeof(*abort_code))
return -EINVAL;
*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
_debug("Abort %x", *abort_code);
if (*abort_code == 0)
return -EINVAL;
break;
case RXRPC_ACCEPT:
if (*command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
*command = RXRPC_CMD_ACCEPT;
if (len != 0)
return -EINVAL;
if (!server)
return -EISCONN;
break;
default:
return -EINVAL;
}
}
_leave(" = 0");
return 0;
}
/*
* abort a call, sending an ABORT packet to the peer
*/
static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
{
write_lock_bh(&call->state_lock);
if (call->state <= RXRPC_CALL_COMPLETE) {
call->state = RXRPC_CALL_LOCALLY_ABORTED;
call->abort_code = abort_code;
set_bit(RXRPC_CALL_ABORT, &call->events);
del_timer_sync(&call->resend_timer);
del_timer_sync(&call->ack_timer);
clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
clear_bit(RXRPC_CALL_ACK, &call->events);
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
rxrpc_queue_call(call);
}
write_unlock_bh(&call->state_lock);
}
/*
* send a message forming part of a client call through an RxRPC socket
* - caller holds the socket locked
* - the socket may be either a client socket or a server socket
*/
int rxrpc_client_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
struct rxrpc_transport *trans, struct msghdr *msg,
size_t len)
{
struct rxrpc_conn_bundle *bundle;
enum rxrpc_command cmd;
struct rxrpc_call *call;
unsigned long user_call_ID = 0;
struct key *key;
__be16 service_id;
u32 abort_code = 0;
int ret;
_enter("");
ASSERT(trans != NULL);
ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
false);
if (ret < 0)
return ret;
bundle = NULL;
if (trans) {
service_id = rx->service_id;
if (msg->msg_name) {
struct sockaddr_rxrpc *srx =
(struct sockaddr_rxrpc *) msg->msg_name;
service_id = htons(srx->srx_service);
}
key = rx->key;
if (key && !rx->key->payload.data)
key = NULL;
bundle = rxrpc_get_bundle(rx, trans, key, service_id,
GFP_KERNEL);
if (IS_ERR(bundle))
return PTR_ERR(bundle);
}
call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
abort_code == 0, GFP_KERNEL);
if (trans)
rxrpc_put_bundle(trans, bundle);
if (IS_ERR(call)) {
_leave(" = %ld", PTR_ERR(call));
return PTR_ERR(call);
}
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
if (call->state >= RXRPC_CALL_COMPLETE) {
/* it's too late for this call */
ret = -ESHUTDOWN;
} else if (cmd == RXRPC_CMD_SEND_ABORT) {
rxrpc_send_abort(call, abort_code);
} else if (cmd != RXRPC_CMD_SEND_DATA) {
ret = -EINVAL;
} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
/* request phase complete for this client call */
ret = -EPROTO;
} else {
ret = rxrpc_send_data(iocb, rx, call, msg, len);
}
rxrpc_put_call(call);
_leave(" = %d", ret);
return ret;
}
/**
* rxrpc_kernel_send_data - Allow a kernel service to send data on a call
* @call: The call to send data through
* @msg: The data to send
* @len: The amount of data to send
*
* Allow a kernel service to send data on a call. The call must be in an state
* appropriate to sending data. No control data should be supplied in @msg,
* nor should an address be supplied. MSG_MORE should be flagged if there's
* more data to come, otherwise this data will end the transmission phase.
*/
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len)
{
int ret;
_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
ASSERTCMP(msg->msg_name, ==, NULL);
ASSERTCMP(msg->msg_control, ==, NULL);
lock_sock(&call->socket->sk);
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
if (call->state >= RXRPC_CALL_COMPLETE) {
ret = -ESHUTDOWN; /* it's too late for this call */
} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
ret = -EPROTO; /* request phase complete for this client call */
} else {
mm_segment_t oldfs = get_fs();
set_fs(KERNEL_DS);
ret = rxrpc_send_data(NULL, call->socket, call, msg, len);
set_fs(oldfs);
}
release_sock(&call->socket->sk);
_leave(" = %d", ret);
return ret;
}
EXPORT_SYMBOL(rxrpc_kernel_send_data);
/*
* rxrpc_kernel_abort_call - Allow a kernel service to abort a call
* @call: The call to be aborted
* @abort_code: The abort code to stick into the ABORT packet
*
* Allow a kernel service to abort a call, if it's still in an abortable state.
*/
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
{
_enter("{%d},%d", call->debug_id, abort_code);
lock_sock(&call->socket->sk);
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
if (call->state < RXRPC_CALL_COMPLETE)
rxrpc_send_abort(call, abort_code);
release_sock(&call->socket->sk);
_leave("");
}
EXPORT_SYMBOL(rxrpc_kernel_abort_call);
/*
* send a message through a server socket
* - caller holds the socket locked
*/
int rxrpc_server_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
struct msghdr *msg, size_t len)
{
enum rxrpc_command cmd;
struct rxrpc_call *call;
unsigned long user_call_ID = 0;
u32 abort_code = 0;
int ret;
_enter("");
ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
true);
if (ret < 0)
return ret;
if (cmd == RXRPC_CMD_ACCEPT) {
call = rxrpc_accept_call(rx, user_call_ID);
if (IS_ERR(call))
return PTR_ERR(call);
rxrpc_put_call(call);
return 0;
}
call = rxrpc_find_server_call(rx, user_call_ID);
if (!call)
return -EBADSLT;
if (call->state >= RXRPC_CALL_COMPLETE) {
ret = -ESHUTDOWN;
goto out;
}
switch (cmd) {
case RXRPC_CMD_SEND_DATA:
if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
/* Tx phase not yet begun for this call */
ret = -EPROTO;
break;
}
ret = rxrpc_send_data(iocb, rx, call, msg, len);
break;
case RXRPC_CMD_SEND_ABORT:
rxrpc_send_abort(call, abort_code);
break;
default:
BUG();
}
out:
rxrpc_put_call(call);
_leave(" = %d", ret);
return ret;
}
/*
* send a packet through the transport endpoint
*/
int rxrpc_send_packet(struct rxrpc_transport *trans, struct sk_buff *skb)
{
struct kvec iov[1];
struct msghdr msg;
int ret, opt;
_enter(",{%d}", skb->len);
iov[0].iov_base = skb->head;
iov[0].iov_len = skb->len;
msg.msg_name = &trans->peer->srx.transport.sin;
msg.msg_namelen = sizeof(trans->peer->srx.transport.sin);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
if (skb->len - sizeof(struct rxrpc_header) < trans->peer->maxdata) {
down_read(&trans->local->defrag_sem);
/* send the packet by UDP
* - returns -EMSGSIZE if UDP would have to fragment the packet
* to go out of the interface
* - in which case, we'll have processed the ICMP error
* message and update the peer record
*/
ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
iov[0].iov_len);
up_read(&trans->local->defrag_sem);
if (ret == -EMSGSIZE)
goto send_fragmentable;
_leave(" = %d [%u]", ret, trans->peer->maxdata);
return ret;
}
send_fragmentable:
/* attempt to send this message with fragmentation enabled */
_debug("send fragment");
down_write(&trans->local->defrag_sem);
opt = IP_PMTUDISC_DONT;
ret = kernel_setsockopt(trans->local->socket, SOL_IP, IP_MTU_DISCOVER,
(char *) &opt, sizeof(opt));
if (ret == 0) {
ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
iov[0].iov_len);
opt = IP_PMTUDISC_DO;
kernel_setsockopt(trans->local->socket, SOL_IP,
IP_MTU_DISCOVER, (char *) &opt, sizeof(opt));
}
up_write(&trans->local->defrag_sem);
_leave(" = %d [frag %u]", ret, trans->peer->maxdata);
return ret;
}
/*
* wait for space to appear in the transmit/ACK window
* - caller holds the socket locked
*/
static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
struct rxrpc_call *call,
long *timeo)
{
DECLARE_WAITQUEUE(myself, current);
int ret;
_enter(",{%d},%ld",
CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),
*timeo);
add_wait_queue(&call->tx_waitq, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
ret = 0;
if (CIRC_SPACE(call->acks_head, call->acks_tail,
call->acks_winsz) > 0)
break;
if (signal_pending(current)) {
ret = sock_intr_errno(*timeo);
break;
}
release_sock(&rx->sk);
*timeo = schedule_timeout(*timeo);
lock_sock(&rx->sk);
}
remove_wait_queue(&call->tx_waitq, &myself);
set_current_state(TASK_RUNNING);
_leave(" = %d", ret);
return ret;
}
/*
* attempt to schedule an instant Tx resend
*/
static inline void rxrpc_instant_resend(struct rxrpc_call *call)
{
read_lock_bh(&call->state_lock);
if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
if (call->state < RXRPC_CALL_COMPLETE &&
!test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
rxrpc_queue_call(call);
}
read_unlock_bh(&call->state_lock);
}
/*
* queue a packet for transmission, set the resend timer and attempt
* to send the packet immediately
*/
static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
bool last)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
int ret;
_net("queue skb %p [%d]", skb, call->acks_head);
ASSERT(call->acks_window != NULL);
call->acks_window[call->acks_head] = (unsigned long) skb;
smp_wmb();
call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
_debug("________awaiting reply/ACK__________");
write_lock_bh(&call->state_lock);
switch (call->state) {
case RXRPC_CALL_CLIENT_SEND_REQUEST:
call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
break;
case RXRPC_CALL_SERVER_ACK_REQUEST:
call->state = RXRPC_CALL_SERVER_SEND_REPLY;
if (!last)
break;
case RXRPC_CALL_SERVER_SEND_REPLY:
call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
break;
default:
break;
}
write_unlock_bh(&call->state_lock);
}
_proto("Tx DATA %%%u { #%u }",
ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
sp->need_resend = 0;
sp->resend_at = jiffies + rxrpc_resend_timeout * HZ;
if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
_debug("run timer");
call->resend_timer.expires = sp->resend_at;
add_timer(&call->resend_timer);
}
/* attempt to cancel the rx-ACK timer, deferring reply transmission if
* we're ACK'ing the request phase of an incoming call */
ret = -EAGAIN;
if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
/* the packet may be freed by rxrpc_process_call() before this
* returns */
ret = rxrpc_send_packet(call->conn->trans, skb);
_net("sent skb %p", skb);
} else {
_debug("failed to delete ACK timer");
}
if (ret < 0) {
_debug("need instant resend %d", ret);
sp->need_resend = 1;
rxrpc_instant_resend(call);
}
_leave("");
}
/*
* send data through a socket
* - must be called in process context
* - caller holds the socket locked
*/
static int rxrpc_send_data(struct kiocb *iocb,
struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct msghdr *msg, size_t len)
{
struct rxrpc_skb_priv *sp;
unsigned char __user *from;
struct sk_buff *skb;
struct iovec *iov;
struct sock *sk = &rx->sk;
long timeo;
bool more;
int ret, ioc, segment, copied;
_enter(",,,{%zu},%zu", msg->msg_iovlen, len);
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
/* this should be in poll */
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
return -EPIPE;
iov = msg->msg_iov;
ioc = msg->msg_iovlen - 1;
from = iov->iov_base;
segment = iov->iov_len;
iov++;
more = msg->msg_flags & MSG_MORE;
skb = call->tx_pending;
call->tx_pending = NULL;
copied = 0;
do {
int copy;
if (segment > len)
segment = len;
_debug("SEGMENT %d @%p", segment, from);
if (!skb) {
size_t size, chunk, max, space;
_debug("alloc");
if (CIRC_SPACE(call->acks_head, call->acks_tail,
call->acks_winsz) <= 0) {
ret = -EAGAIN;
if (msg->msg_flags & MSG_DONTWAIT)
goto maybe_error;
ret = rxrpc_wait_for_tx_window(rx, call,
&timeo);
if (ret < 0)
goto maybe_error;
}
max = call->conn->trans->peer->maxdata;
max -= call->conn->security_size;
max &= ~(call->conn->size_align - 1UL);
chunk = max;
if (chunk > len)
chunk = len;
space = chunk + call->conn->size_align;
space &= ~(call->conn->size_align - 1UL);
size = space + call->conn->header_size;
_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
/* create a buffer that we can retain until it's ACK'd */
skb = sock_alloc_send_skb(
sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
if (!skb)
goto maybe_error;
rxrpc_new_skb(skb);
_debug("ALLOC SEND %p", skb);
ASSERTCMP(skb->mark, ==, 0);
_debug("HS: %u", call->conn->header_size);
skb_reserve(skb, call->conn->header_size);
skb->len += call->conn->header_size;
sp = rxrpc_skb(skb);
sp->remain = chunk;
if (sp->remain > skb_tailroom(skb))
sp->remain = skb_tailroom(skb);
_net("skb: hr %d, tr %d, hl %d, rm %d",
skb_headroom(skb),
skb_tailroom(skb),
skb_headlen(skb),
sp->remain);
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
_debug("append");
sp = rxrpc_skb(skb);
/* append next segment of data to the current buffer */
copy = skb_tailroom(skb);
ASSERTCMP(copy, >, 0);
if (copy > segment)
copy = segment;
if (copy > sp->remain)
copy = sp->remain;
_debug("add");
ret = skb_add_data(skb, from, copy);
_debug("added");
if (ret < 0)
goto efault;
sp->remain -= copy;
skb->mark += copy;
len -= copy;
segment -= copy;
from += copy;
while (segment == 0 && ioc > 0) {
from = iov->iov_base;
segment = iov->iov_len;
iov++;
ioc--;
}
if (len == 0) {
segment = 0;
ioc = 0;
}
/* check for the far side aborting the call or a network error
* occurring */
if (call->state > RXRPC_CALL_COMPLETE)
goto call_aborted;
/* add the packet to the send queue if it's now full */
if (sp->remain <= 0 || (segment == 0 && !more)) {
struct rxrpc_connection *conn = call->conn;
size_t pad;
/* pad out if we're using security */
if (conn->security) {
pad = conn->security_size + skb->mark;
pad = conn->size_align - pad;
pad &= conn->size_align - 1;
_debug("pad %zu", pad);
if (pad)
memset(skb_put(skb, pad), 0, pad);
}
sp->hdr.epoch = conn->epoch;
sp->hdr.cid = call->cid;
sp->hdr.callNumber = call->call_id;
sp->hdr.seq =
htonl(atomic_inc_return(&call->sequence));
sp->hdr.serial =
htonl(atomic_inc_return(&conn->serial));
sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
sp->hdr.userStatus = 0;
sp->hdr.securityIndex = conn->security_ix;
sp->hdr._rsvd = 0;
sp->hdr.serviceId = conn->service_id;
sp->hdr.flags = conn->out_clientflag;
if (len == 0 && !more)
sp->hdr.flags |= RXRPC_LAST_PACKET;
else if (CIRC_SPACE(call->acks_head, call->acks_tail,
call->acks_winsz) > 1)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
ret = rxrpc_secure_packet(
call, skb, skb->mark,
skb->head + sizeof(struct rxrpc_header));
if (ret < 0)
goto out;
memcpy(skb->head, &sp->hdr,
sizeof(struct rxrpc_header));
rxrpc_queue_packet(call, skb, segment == 0 && !more);
skb = NULL;
}
} while (segment > 0);
out:
call->tx_pending = skb;
_leave(" = %d", ret);
return ret;
call_aborted:
rxrpc_free_skb(skb);
if (call->state == RXRPC_CALL_NETWORK_ERROR)
ret = call->conn->trans->peer->net_error;
else
ret = -ECONNABORTED;
_leave(" = %d", ret);
return ret;
maybe_error:
if (copied)
ret = copied;
goto out;
efault:
ret = -EFAULT;
goto out;
}
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