/* * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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 <net/net_namespace.h>#include <net/netns/generic.h>#include <linux/ipv6.h> #include "rds_single_path.h"#include "rds.h"#include "loop.h" static DEFINE_SPINLOCK(loop_conns_lock);static LIST_HEAD(loop_conns);static atomic_t rds_loop_unloading = ATOMIC_INIT(0); static void rds_loop_set_unloading(void){	atomic_set(&rds_loop_unloading, 1);} static bool rds_loop_is_unloading(struct rds_connection *conn){	return atomic_read(&rds_loop_unloading) != 0;} /* * 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); 	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_path(struct rds_conn_path *cp){	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);	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_path_connect(struct rds_conn_path *cp){	rds_connect_complete(cp->cp_conn);	return 0;} static void rds_loop_conn_path_shutdown(struct rds_conn_path *cp){} void rds_loop_exit(void){	struct rds_loop_connection *lc, *_lc;	LIST_HEAD(tmp_list); 	rds_loop_set_unloading();	synchronize_rcu();	/* 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);	}} static void rds_loop_kill_conns(struct net *net){	struct rds_loop_connection *lc, *_lc;	LIST_HEAD(tmp_list); 	spin_lock_irq(&loop_conns_lock);	list_for_each_entry_safe(lc, _lc, &loop_conns, loop_node)  {		struct net *c_net = read_pnet(&lc->conn->c_net); 		if (net != c_net)			continue;		list_move_tail(&lc->loop_node, &tmp_list);	}	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);	}} static void __net_exit rds_loop_exit_net(struct net *net){	rds_loop_kill_conns(net);} static struct pernet_operations rds_loop_net_ops = {	.exit = rds_loop_exit_net,}; int rds_loop_net_init(void){	return register_pernet_device(&rds_loop_net_ops);} void rds_loop_net_exit(void){	unregister_pernet_device(&rds_loop_net_ops);} /* * 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_path		= rds_loop_recv_path,	.conn_alloc		= rds_loop_conn_alloc,	.conn_free		= rds_loop_conn_free,	.conn_path_connect	= rds_loop_conn_path_connect,	.conn_path_shutdown	= rds_loop_conn_path_shutdown,	.inc_copy_to_user	= rds_message_inc_copy_to_user,	.inc_free		= rds_loop_inc_free,	.t_name			= "loopback",	.t_type			= RDS_TRANS_LOOP,	.t_unloading		= rds_loop_is_unloading,};