ar-call.c

linux 内核源代码

/* RxRPC individual remote procedure call handling
 *
 * 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/module.h>
#include <linux/circ_buf.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

const char *rxrpc_call_states[] = {
	[RXRPC_CALL_CLIENT_SEND_REQUEST]	= "ClSndReq",
	[RXRPC_CALL_CLIENT_AWAIT_REPLY]		= "ClAwtRpl",
	[RXRPC_CALL_CLIENT_RECV_REPLY]		= "ClRcvRpl",
	[RXRPC_CALL_CLIENT_FINAL_ACK]		= "ClFnlACK",
	[RXRPC_CALL_SERVER_SECURING]		= "SvSecure",
	[RXRPC_CALL_SERVER_ACCEPTING]		= "SvAccept",
	[RXRPC_CALL_SERVER_RECV_REQUEST]	= "SvRcvReq",
	[RXRPC_CALL_SERVER_ACK_REQUEST]		= "SvAckReq",
	[RXRPC_CALL_SERVER_SEND_REPLY]		= "SvSndRpl",
	[RXRPC_CALL_SERVER_AWAIT_ACK]		= "SvAwtACK",
	[RXRPC_CALL_COMPLETE]			= "Complete",
	[RXRPC_CALL_SERVER_BUSY]		= "SvBusy  ",
	[RXRPC_CALL_REMOTELY_ABORTED]		= "RmtAbort",
	[RXRPC_CALL_LOCALLY_ABORTED]		= "LocAbort",
	[RXRPC_CALL_NETWORK_ERROR]		= "NetError",
	[RXRPC_CALL_DEAD]			= "Dead    ",
};

struct kmem_cache *rxrpc_call_jar;
LIST_HEAD(rxrpc_calls);
DEFINE_RWLOCK(rxrpc_call_lock);
static unsigned rxrpc_call_max_lifetime = 60;
static unsigned rxrpc_dead_call_timeout = 2;

static void rxrpc_destroy_call(struct work_struct *work);
static void rxrpc_call_life_expired(unsigned long _call);
static void rxrpc_dead_call_expired(unsigned long _call);
static void rxrpc_ack_time_expired(unsigned long _call);
static void rxrpc_resend_time_expired(unsigned long _call);

/*
 * allocate a new call
 */
static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
{
	struct rxrpc_call *call;

	call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
	if (!call)
		return NULL;

	call->acks_winsz = 16;
	call->acks_window = kmalloc(call->acks_winsz * sizeof(unsigned long),
				    gfp);
	if (!call->acks_window) {
		kmem_cache_free(rxrpc_call_jar, call);
		return NULL;
	}

	setup_timer(&call->lifetimer, &rxrpc_call_life_expired,
		    (unsigned long) call);
	setup_timer(&call->deadspan, &rxrpc_dead_call_expired,
		    (unsigned long) call);
	setup_timer(&call->ack_timer, &rxrpc_ack_time_expired,
		    (unsigned long) call);
	setup_timer(&call->resend_timer, &rxrpc_resend_time_expired,
		    (unsigned long) call);
	INIT_WORK(&call->destroyer, &rxrpc_destroy_call);
	INIT_WORK(&call->processor, &rxrpc_process_call);
	INIT_LIST_HEAD(&call->accept_link);
	skb_queue_head_init(&call->rx_queue);
	skb_queue_head_init(&call->rx_oos_queue);
	init_waitqueue_head(&call->tx_waitq);
	spin_lock_init(&call->lock);
	rwlock_init(&call->state_lock);
	atomic_set(&call->usage, 1);
	call->debug_id = atomic_inc_return(&rxrpc_debug_id);
	call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;

	memset(&call->sock_node, 0xed, sizeof(call->sock_node));

	call->rx_data_expect = 1;
	call->rx_data_eaten = 0;
	call->rx_first_oos = 0;
	call->ackr_win_top = call->rx_data_eaten + 1 + RXRPC_MAXACKS;
	call->creation_jif = jiffies;
	return call;
}

/*
 * allocate a new client call and attempt to to get a connection slot for it
 */
static struct rxrpc_call *rxrpc_alloc_client_call(
	struct rxrpc_sock *rx,
	struct rxrpc_transport *trans,
	struct rxrpc_conn_bundle *bundle,
	gfp_t gfp)
{
	struct rxrpc_call *call;
	int ret;

	_enter("");

	ASSERT(rx != NULL);
	ASSERT(trans != NULL);
	ASSERT(bundle != NULL);

	call = rxrpc_alloc_call(gfp);
	if (!call)
		return ERR_PTR(-ENOMEM);

	sock_hold(&rx->sk);
	call->socket = rx;
	call->rx_data_post = 1;

	ret = rxrpc_connect_call(rx, trans, bundle, call, gfp);
	if (ret < 0) {
		kmem_cache_free(rxrpc_call_jar, call);
		return ERR_PTR(ret);
	}

	spin_lock(&call->conn->trans->peer->lock);
	list_add(&call->error_link, &call->conn->trans->peer->error_targets);
	spin_unlock(&call->conn->trans->peer->lock);

	call->lifetimer.expires = jiffies + rxrpc_call_max_lifetime * HZ;
	add_timer(&call->lifetimer);

	_leave(" = %p", call);
	return call;
}

/*
 * set up a call for the given data
 * - called in process context with IRQs enabled
 */
struct rxrpc_call *rxrpc_get_client_call(struct rxrpc_sock *rx,
					 struct rxrpc_transport *trans,
					 struct rxrpc_conn_bundle *bundle,
					 unsigned long user_call_ID,
					 int create,
					 gfp_t gfp)
{
	struct rxrpc_call *call, *candidate;
	struct rb_node *p, *parent, **pp;

	_enter("%p,%d,%d,%lx,%d",
	       rx, trans ? trans->debug_id : -1, bundle ? bundle->debug_id : -1,
	       user_call_ID, create);

	/* search the extant calls first for one that matches the specified
	 * user ID */
	read_lock(&rx->call_lock);

	p = rx->calls.rb_node;
	while (p) {
		call = rb_entry(p, struct rxrpc_call, sock_node);

		if (user_call_ID < call->user_call_ID)
			p = p->rb_left;
		else if (user_call_ID > call->user_call_ID)
			p = p->rb_right;
		else
			goto found_extant_call;
	}

	read_unlock(&rx->call_lock);

	if (!create || !trans)
		return ERR_PTR(-EBADSLT);

	/* not yet present - create a candidate for a new record and then
	 * redo the search */
	candidate = rxrpc_alloc_client_call(rx, trans, bundle, gfp);
	if (IS_ERR(candidate)) {
		_leave(" = %ld", PTR_ERR(candidate));
		return candidate;
	}

	candidate->user_call_ID = user_call_ID;
	__set_bit(RXRPC_CALL_HAS_USERID, &candidate->flags);

	write_lock(&rx->call_lock);

	pp = &rx->calls.rb_node;
	parent = NULL;
	while (*pp) {
		parent = *pp;
		call = rb_entry(parent, struct rxrpc_call, sock_node);

		if (user_call_ID < call->user_call_ID)
			pp = &(*pp)->rb_left;
		else if (user_call_ID > call->user_call_ID)
			pp = &(*pp)->rb_right;
		else
			goto found_extant_second;
	}

	/* second search also failed; add the new call */
	call = candidate;
	candidate = NULL;
	rxrpc_get_call(call);

	rb_link_node(&call->sock_node, parent, pp);
	rb_insert_color(&call->sock_node, &rx->calls);
	write_unlock(&rx->call_lock);

	write_lock_bh(&rxrpc_call_lock);
	list_add_tail(&call->link, &rxrpc_calls);
	write_unlock_bh(&rxrpc_call_lock);

	_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);

	_leave(" = %p [new]", call);
	return call;

	/* we found the call in the list immediately */
found_extant_call:
	rxrpc_get_call(call);
	read_unlock(&rx->call_lock);
	_leave(" = %p [extant %d]", call, atomic_read(&call->usage));
	return call;

	/* we found the call on the second time through the list */
found_extant_second:
	rxrpc_get_call(call);
	write_unlock(&rx->call_lock);
	rxrpc_put_call(candidate);
	_leave(" = %p [second %d]", call, atomic_read(&call->usage));
	return call;
}

/*
 * set up an incoming call
 * - called in process context with IRQs enabled
 */
struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *rx,
				       struct rxrpc_connection *conn,
				       struct rxrpc_header *hdr,
				       gfp_t gfp)
{
	struct rxrpc_call *call, *candidate;
	struct rb_node **p, *parent;
	__be32 call_id;

	_enter(",%d,,%x", conn->debug_id, gfp);

	ASSERT(rx != NULL);

	candidate = rxrpc_alloc_call(gfp);
	if (!candidate)
		return ERR_PTR(-EBUSY);

	candidate->socket = rx;
	candidate->conn = conn;
	candidate->cid = hdr->cid;
	candidate->call_id = hdr->callNumber;
	candidate->channel = ntohl(hdr->cid) & RXRPC_CHANNELMASK;
	candidate->rx_data_post = 0;
	candidate->state = RXRPC_CALL_SERVER_ACCEPTING;
	if (conn->security_ix > 0)
		candidate->state = RXRPC_CALL_SERVER_SECURING;

	write_lock_bh(&conn->lock);

	/* set the channel for this call */
	call = conn->channels[candidate->channel];
	_debug("channel[%u] is %p", candidate->channel, call);
	if (call && call->call_id == hdr->callNumber) {
		/* already set; must've been a duplicate packet */
		_debug("extant call [%d]", call->state);
		ASSERTCMP(call->conn, ==, conn);

		read_lock(&call->state_lock);
		switch (call->state) {
		case RXRPC_CALL_LOCALLY_ABORTED:
			if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
				rxrpc_queue_call(call);
		case RXRPC_CALL_REMOTELY_ABORTED:
			read_unlock(&call->state_lock);
			goto aborted_call;
		default:
			rxrpc_get_call(call);
			read_unlock(&call->state_lock);
			goto extant_call;
		}
	}

	if (call) {
		/* it seems the channel is still in use from the previous call
		 * - ditch the old binding if its call is now complete */
		_debug("CALL: %u { %s }",
		       call->debug_id, rxrpc_call_states[call->state]);

		if (call->state >= RXRPC_CALL_COMPLETE) {
			conn->channels[call->channel] = NULL;
		} else {
			write_unlock_bh(&conn->lock);
			kmem_cache_free(rxrpc_call_jar, candidate);
			_leave(" = -EBUSY");
			return ERR_PTR(-EBUSY);
		}
	}

	/* check the call number isn't duplicate */
	_debug("check dup");
	call_id = hdr->callNumber;
	p = &conn->calls.rb_node;
	parent = NULL;
	while (*p) {
		parent = *p;
		call = rb_entry(parent, struct rxrpc_call, conn_node);

		if (call_id < call->call_id)
			p = &(*p)->rb_left;
		else if (call_id > call->call_id)
			p = &(*p)->rb_right;
		else
			goto old_call;
	}

	/* make the call available */
	_debug("new call");
	call = candidate;
	candidate = NULL;
	rb_link_node(&call->conn_node, parent, p);
	rb_insert_color(&call->conn_node, &conn->calls);
	conn->channels[call->channel] = call;
	sock_hold(&rx->sk);
	atomic_inc(&conn->usage);
	write_unlock_bh(&conn->lock);

	spin_lock(&conn->trans->peer->lock);
	list_add(&call->error_link, &conn->trans->peer->error_targets);
	spin_unlock(&conn->trans->peer->lock);

	write_lock_bh(&rxrpc_call_lock);
	list_add_tail(&call->link, &rxrpc_calls);
	write_unlock_bh(&rxrpc_call_lock);

	_net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);

	call->lifetimer.expires = jiffies + rxrpc_call_max_lifetime * HZ;
	add_timer(&call->lifetimer);
	_leave(" = %p {%d} [new]", call, call->debug_id);
	return call;

extant_call:
	write_unlock_bh(&conn->lock);
	kmem_cache_free(rxrpc_call_jar, candidate);
	_leave(" = %p {%d} [extant]", call, call ? call->debug_id : -1);
	return call;

aborted_call:
	write_unlock_bh(&conn->lock);
	kmem_cache_free(rxrpc_call_jar, candidate);
	_leave(" = -ECONNABORTED");
	return ERR_PTR(-ECONNABORTED);

old_call:
	write_unlock_bh(&conn->lock);
	kmem_cache_free(rxrpc_call_jar, candidate);
	_leave(" = -ECONNRESET [old]");
	return ERR_PTR(-ECONNRESET);
}

/*
 * find an extant server call
 * - called in process context with IRQs enabled
 */
struct rxrpc_call *rxrpc_find_server_call(struct rxrpc_sock *rx,
					  unsigned long user_call_ID)
{
	struct rxrpc_call *call;
	struct rb_node *p;

	_enter("%p,%lx", rx, user_call_ID);

	/* search the extant calls for one that matches the specified user
	 * ID */
	read_lock(&rx->call_lock);

	p = rx->calls.rb_node;
	while (p) {
		call = rb_entry(p, struct rxrpc_call, sock_node);

		if (user_call_ID < call->user_call_ID)
			p = p->rb_left;
		else if (user_call_ID > call->user_call_ID)
			p = p->rb_right;
		else
			goto found_extant_call;
	}

	read_unlock(&rx->call_lock);
	_leave(" = NULL");
	return NULL;

	/* we found the call in the list immediately */
found_extant_call:
	rxrpc_get_call(call);
	read_unlock(&rx->call_lock);
	_leave(" = %p [%d]", call, atomic_read(&call->usage));
	return call;