ar-output.c

linux 内核源代码

/* RxRPC packet transmission
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([e-mail])
 *
 * 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;
	}