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 #include <net/net_namespace.h> 37 #include <net/netns/generic.h> 38 39 #include "rds_single_path.h" 40 #include "rds.h" 41 #include "loop.h" 42 43 static DEFINE_SPINLOCK(loop_conns_lock); 44 static LIST_HEAD(loop_conns); 45 static atomic_t rds_loop_unloading = ATOMIC_INIT(0); 46 47 static void rds_loop_set_unloading(void) 48 { 49 atomic_set(&rds_loop_unloading, 1); 50 } 51 52 static bool rds_loop_is_unloading(struct rds_connection *conn) 53 { 54 return atomic_read(&rds_loop_unloading) != 0; 55 } 56 57 /* 58 * This 'loopback' transport is a special case for flows that originate 59 * and terminate on the same machine. 60 * 61 * Connection build-up notices if the destination address is thought of 62 * as a local address by a transport. At that time it decides to use the 63 * loopback transport instead of the bound transport of the sending socket. 64 * 65 * The loopback transport's sending path just hands the sent rds_message 66 * straight to the receiving path via an embedded rds_incoming. 67 */ 68 69 /* 70 * Usually a message transits both the sender and receiver's conns as it 71 * flows to the receiver. In the loopback case, though, the receive path 72 * is handed the sending conn so the sense of the addresses is reversed. 73 */ 74 static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, 75 unsigned int hdr_off, unsigned int sg, 76 unsigned int off) 77 { 78 struct scatterlist *sgp = &rm->data.op_sg[sg]; 79 int ret = sizeof(struct rds_header) + 80 be32_to_cpu(rm->m_inc.i_hdr.h_len); 81 82 /* Do not send cong updates to loopback */ 83 if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { 84 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 85 ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off); 86 goto out; 87 } 88 89 BUG_ON(hdr_off || sg || off); 90 91 rds_inc_init(&rm->m_inc, conn, conn->c_laddr); 92 /* For the embedded inc. Matching put is in loop_inc_free() */ 93 rds_message_addref(rm); 94 95 rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc, 96 GFP_KERNEL); 97 98 rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), 99 NULL); 100 101 rds_inc_put(&rm->m_inc); 102 out: 103 return ret; 104 } 105 106 /* 107 * See rds_loop_xmit(). Since our inc is embedded in the rm, we 108 * make sure the rm lives at least until the inc is done. 109 */ 110 static void rds_loop_inc_free(struct rds_incoming *inc) 111 { 112 struct rds_message *rm = container_of(inc, struct rds_message, m_inc); 113 114 rds_message_put(rm); 115 } 116 117 /* we need to at least give the thread something to succeed */ 118 static int rds_loop_recv_path(struct rds_conn_path *cp) 119 { 120 return 0; 121 } 122 123 struct rds_loop_connection { 124 struct list_head loop_node; 125 struct rds_connection *conn; 126 }; 127 128 /* 129 * Even the loopback transport needs to keep track of its connections, 130 * so it can call rds_conn_destroy() on them on exit. N.B. there are 131 * 1+ loopback addresses (127.*.*.*) so it's not a bug to have 132 * multiple loopback conns allocated, although rather useless. 133 */ 134 static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) 135 { 136 struct rds_loop_connection *lc; 137 unsigned long flags; 138 139 lc = kzalloc(sizeof(struct rds_loop_connection), gfp); 140 if (!lc) 141 return -ENOMEM; 142 143 INIT_LIST_HEAD(&lc->loop_node); 144 lc->conn = conn; 145 conn->c_transport_data = lc; 146 147 spin_lock_irqsave(&loop_conns_lock, flags); 148 list_add_tail(&lc->loop_node, &loop_conns); 149 spin_unlock_irqrestore(&loop_conns_lock, flags); 150 151 return 0; 152 } 153 154 static void rds_loop_conn_free(void *arg) 155 { 156 struct rds_loop_connection *lc = arg; 157 unsigned long flags; 158 159 rdsdebug("lc %p\n", lc); 160 spin_lock_irqsave(&loop_conns_lock, flags); 161 list_del(&lc->loop_node); 162 spin_unlock_irqrestore(&loop_conns_lock, flags); 163 kfree(lc); 164 } 165 166 static int rds_loop_conn_path_connect(struct rds_conn_path *cp) 167 { 168 rds_connect_complete(cp->cp_conn); 169 return 0; 170 } 171 172 static void rds_loop_conn_path_shutdown(struct rds_conn_path *cp) 173 { 174 } 175 176 void rds_loop_exit(void) 177 { 178 struct rds_loop_connection *lc, *_lc; 179 LIST_HEAD(tmp_list); 180 181 rds_loop_set_unloading(); 182 synchronize_rcu(); 183 /* avoid calling conn_destroy with irqs off */ 184 spin_lock_irq(&loop_conns_lock); 185 list_splice(&loop_conns, &tmp_list); 186 INIT_LIST_HEAD(&loop_conns); 187 spin_unlock_irq(&loop_conns_lock); 188 189 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 190 WARN_ON(lc->conn->c_passive); 191 rds_conn_destroy(lc->conn); 192 } 193 } 194 195 static void rds_loop_kill_conns(struct net *net) 196 { 197 struct rds_loop_connection *lc, *_lc; 198 LIST_HEAD(tmp_list); 199 200 spin_lock_irq(&loop_conns_lock); 201 list_for_each_entry_safe(lc, _lc, &loop_conns, loop_node) { 202 struct net *c_net = read_pnet(&lc->conn->c_net); 203 204 if (net != c_net) 205 continue; 206 list_move_tail(&lc->loop_node, &tmp_list); 207 } 208 spin_unlock_irq(&loop_conns_lock); 209 210 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 211 WARN_ON(lc->conn->c_passive); 212 rds_conn_destroy(lc->conn); 213 } 214 } 215 216 static void __net_exit rds_loop_exit_net(struct net *net) 217 { 218 rds_loop_kill_conns(net); 219 } 220 221 static struct pernet_operations rds_loop_net_ops = { 222 .exit = rds_loop_exit_net, 223 }; 224 225 int rds_loop_net_init(void) 226 { 227 return register_pernet_device(&rds_loop_net_ops); 228 } 229 230 void rds_loop_net_exit(void) 231 { 232 unregister_pernet_device(&rds_loop_net_ops); 233 } 234 235 /* 236 * This is missing .xmit_* because loop doesn't go through generic 237 * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and 238 * .laddr_check are missing because transport.c doesn't iterate over 239 * rds_loop_transport. 240 */ 241 struct rds_transport rds_loop_transport = { 242 .xmit = rds_loop_xmit, 243 .recv_path = rds_loop_recv_path, 244 .conn_alloc = rds_loop_conn_alloc, 245 .conn_free = rds_loop_conn_free, 246 .conn_path_connect = rds_loop_conn_path_connect, 247 .conn_path_shutdown = rds_loop_conn_path_shutdown, 248 .inc_copy_to_user = rds_message_inc_copy_to_user, 249 .inc_free = rds_loop_inc_free, 250 .t_name = "loopback", 251 .t_type = RDS_TRANS_LOOP, 252 .t_unloading = rds_loop_is_unloading, 253 }; 254