/*
* Copyright (c) 2006 Oracle. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/in.h>
#include "rds.h"
#include "loop.h"
static DEFINE_SPINLOCK(loop_conns_lock);
static LIST_HEAD(loop_conns);
/*
* This 'loopback' transport is a special case for flows that originate
* and terminate on the same machine.
*
* Connection build-up notices if the destination address is thought of
* as a local address by a transport. At that time it decides to use the
* loopback transport instead of the bound transport of the sending socket.
*
* The loopback transport's sending path just hands the sent rds_message
* straight to the receiving path via an embedded rds_incoming.
*/
/*
* Usually a message transits both the sender and receiver's conns as it
* flows to the receiver. In the loopback case, though, the receive path
* is handed the sending conn so the sense of the addresses is reversed.
*/
static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm,
unsigned int hdr_off, unsigned int sg,
unsigned int off)
{
struct scatterlist *sgp = &rm->data.op_sg[sg];
int ret = sizeof(struct rds_header) +
be32_to_cpu(rm->m_inc.i_hdr.h_len);
/* Do not send cong updates to loopback */
if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off);
goto out;
}
BUG_ON(hdr_off || sg || off);
rds_inc_init(&rm->m_inc, conn, conn->c_laddr);
/* For the embedded inc. Matching put is in loop_inc_free() */
rds_message_addref(rm);
rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc,
GFP_KERNEL, KM_USER0);
rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence),
NULL);
rds_inc_put(&rm->m_inc);
out:
return ret;
}
/*
* See rds_loop_xmit(). Since our inc is embedded in the rm, we
* make sure the rm lives at least until the inc is done.
*/
static void rds_loop_inc_free(struct rds_incoming *inc)
{
struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
rds_message_put(rm);
}
/* we need to at least give the thread something to succeed */
static int rds_loop_recv(struct rds_connection *conn)
{
return 0;
}
struct rds_loop_connection {
struct list_head loop_node;
struct rds_connection *conn;
};
/*
* Even the loopback transport needs to keep track of its connections,
* so it can call rds_conn_destroy() on them on exit. N.B. there are
* 1+ loopback addresses (127.*.*.*) so it's not a bug to have
* multiple loopback conns allocated, although rather useless.
*/
static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp)
{
struct rds_loop_connection *lc;
unsigned long flags;
lc = kzalloc(sizeof(struct rds_loop_connection), GFP_KERNEL);
if (!lc)
return -ENOMEM;
INIT_LIST_HEAD(&lc->loop_node);
lc->conn = conn;
conn->c_transport_data = lc;
spin_lock_irqsave(&loop_conns_lock, flags);
list_add_tail(&lc->loop_node, &loop_conns);
spin_unlock_irqrestore(&loop_conns_lock, flags);
return 0;
}
static void rds_loop_conn_free(void *arg)
{
struct rds_loop_connection *lc = arg;
unsigned long flags;
rdsdebug("lc %p\n", lc);
spin_lock_irqsave(&loop_conns_lock, flags);
list_del(&lc->loop_node);
spin_unlock_irqrestore(&loop_conns_lock, flags);
kfree(lc);
}
static int rds_loop_conn_connect(struct rds_connection *conn)
{
rds_connect_complete(conn);
return 0;
}
static void rds_loop_conn_shutdown(struct rds_connection *conn)
{
}
void rds_loop_exit(void)
{
struct rds_loop_connection *lc, *_lc;
LIST_HEAD(tmp_list);
/* avoid calling conn_destroy with irqs off */
spin_lock_irq(&loop_conns_lock);
list_splice(&loop_conns, &tmp_list);
INIT_LIST_HEAD(&loop_conns);
spin_unlock_irq(&loop_conns_lock);
list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) {
WARN_ON(lc->conn->c_passive);
rds_conn_destroy(lc->conn);
}
}
/*
* This is missing .xmit_* because loop doesn't go through generic
* rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and
* .laddr_check are missing because transport.c doesn't iterate over
* rds_loop_transport.
*/
struct rds_transport rds_loop_transport = {
.xmit = rds_loop_xmit,
.recv = rds_loop_recv,
.conn_alloc = rds_loop_conn_alloc,
.conn_free = rds_loop_conn_free,
.conn_connect = rds_loop_conn_connect,
.conn_shutdown = rds_loop_conn_shutdown,
.inc_copy_to_user = rds_message_inc_copy_to_user,
.inc_free = rds_loop_inc_free,
.t_name = "loopback",
};
