1/* 2 * Copyright (c) 2006 Oracle. All rights reserved. 3 * 4 * This software is available to you under a choice of one of two 5 * licenses. You may choose to be licensed under the terms of the GNU 6 * General Public License (GPL) Version 2, available from the file 7 * COPYING in the main directory of this source tree, or the 8 * OpenIB.org BSD license below: 9 * 10 * Redistribution and use in source and binary forms, with or 11 * without modification, are permitted provided that the following 12 * conditions are met: 13 * 14 * - Redistributions of source code must retain the above 15 * copyright notice, this list of conditions and the following 16 * disclaimer. 17 * 18 * - Redistributions in binary form must reproduce the above 19 * copyright notice, this list of conditions and the following 20 * disclaimer in the documentation and/or other materials 21 * provided with the distribution. 22 * 23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 30 * SOFTWARE. 31 * 32 */ 33#include <linux/kernel.h> 34#include <linux/slab.h> 35#include <linux/in.h> 36 37#include "rds.h" 38#include "loop.h" 39 40static DEFINE_SPINLOCK(loop_conns_lock); 41static LIST_HEAD(loop_conns); 42 43/* 44 * This 'loopback' transport is a special case for flows that originate 45 * and terminate on the same machine. 46 * 47 * Connection build-up notices if the destination address is thought of 48 * as a local address by a transport. At that time it decides to use the 49 * loopback transport instead of the bound transport of the sending socket. 50 * 51 * The loopback transport's sending path just hands the sent rds_message 52 * straight to the receiving path via an embedded rds_incoming. 53 */ 54 55/* 56 * Usually a message transits both the sender and receiver's conns as it 57 * flows to the receiver. In the loopback case, though, the receive path 58 * is handed the sending conn so the sense of the addresses is reversed. 59 */ 60static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, 61 unsigned int hdr_off, unsigned int sg, 62 unsigned int off) 63{ 64 BUG_ON(hdr_off || sg || off); 65 66 rds_inc_init(&rm->m_inc, conn, conn->c_laddr); 67 rds_message_addref(rm); /* for the inc */ 68 69 rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc, 70 GFP_KERNEL, KM_USER0); 71 72 rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), 73 NULL); 74 75 rds_inc_put(&rm->m_inc); 76 77 return sizeof(struct rds_header) + be32_to_cpu(rm->m_inc.i_hdr.h_len); 78} 79 80static int rds_loop_xmit_cong_map(struct rds_connection *conn, 81 struct rds_cong_map *map, 82 unsigned long offset) 83{ 84 BUG_ON(offset); 85 BUG_ON(map != conn->c_lcong); 86 87 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 88 89 return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; 90} 91 92/* we need to at least give the thread something to succeed */ 93static int rds_loop_recv(struct rds_connection *conn) 94{ 95 return 0; 96} 97 98struct rds_loop_connection { 99 struct list_head loop_node; 100 struct rds_connection *conn; 101}; 102 103/* 104 * Even the loopback transport needs to keep track of its connections, 105 * so it can call rds_conn_destroy() on them on exit. N.B. there are 106 * 1+ loopback addresses (127.*.*.*) so it's not a bug to have 107 * multiple loopback conns allocated, although rather useless. 108 */ 109static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) 110{ 111 struct rds_loop_connection *lc; 112 unsigned long flags; 113 114 lc = kzalloc(sizeof(struct rds_loop_connection), GFP_KERNEL); 115 if (lc == NULL) 116 return -ENOMEM; 117 118 INIT_LIST_HEAD(&lc->loop_node); 119 lc->conn = conn; 120 conn->c_transport_data = lc; 121 122 spin_lock_irqsave(&loop_conns_lock, flags); 123 list_add_tail(&lc->loop_node, &loop_conns); 124 spin_unlock_irqrestore(&loop_conns_lock, flags); 125 126 return 0; 127} 128 129static void rds_loop_conn_free(void *arg) 130{ 131 struct rds_loop_connection *lc = arg; 132 rdsdebug("lc %p\n", lc); 133 list_del(&lc->loop_node); 134 kfree(lc); 135} 136 137static int rds_loop_conn_connect(struct rds_connection *conn) 138{ 139 rds_connect_complete(conn); 140 return 0; 141} 142 143static void rds_loop_conn_shutdown(struct rds_connection *conn) 144{ 145} 146 147void rds_loop_exit(void) 148{ 149 struct rds_loop_connection *lc, *_lc; 150 LIST_HEAD(tmp_list); 151 152 /* avoid calling conn_destroy with irqs off */ 153 spin_lock_irq(&loop_conns_lock); 154 list_splice(&loop_conns, &tmp_list); 155 INIT_LIST_HEAD(&loop_conns); 156 spin_unlock_irq(&loop_conns_lock); 157 158 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 159 WARN_ON(lc->conn->c_passive); 160 rds_conn_destroy(lc->conn); 161 } 162} 163 164/* 165 * This is missing .xmit_* because loop doesn't go through generic 166 * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and 167 * .laddr_check are missing because transport.c doesn't iterate over 168 * rds_loop_transport. 169 */ 170struct rds_transport rds_loop_transport = { 171 .xmit = rds_loop_xmit, 172 .xmit_cong_map = rds_loop_xmit_cong_map, 173 .recv = rds_loop_recv, 174 .conn_alloc = rds_loop_conn_alloc, 175 .conn_free = rds_loop_conn_free, 176 .conn_connect = rds_loop_conn_connect, 177 .conn_shutdown = rds_loop_conn_shutdown, 178 .inc_copy_to_user = rds_message_inc_copy_to_user, 179 .inc_purge = rds_message_inc_purge, 180 .inc_free = rds_message_inc_free, 181 .t_name = "loopback", 182}; 183