1 /* 2 * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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 #include <linux/ipv6.h> 39 40 #include "rds_single_path.h" 41 #include "rds.h" 42 #include "loop.h" 43 44 static DEFINE_SPINLOCK(loop_conns_lock); 45 static LIST_HEAD(loop_conns); 46 static atomic_t rds_loop_unloading = ATOMIC_INIT(0); 47 48 static void rds_loop_set_unloading(void) 49 { 50 atomic_set(&rds_loop_unloading, 1); 51 } 52 53 static bool rds_loop_is_unloading(struct rds_connection *conn) 54 { 55 return atomic_read(&rds_loop_unloading) != 0; 56 } 57 58 /* 59 * This 'loopback' transport is a special case for flows that originate 60 * and terminate on the same machine. 61 * 62 * Connection build-up notices if the destination address is thought of 63 * as a local address by a transport. At that time it decides to use the 64 * loopback transport instead of the bound transport of the sending socket. 65 * 66 * The loopback transport's sending path just hands the sent rds_message 67 * straight to the receiving path via an embedded rds_incoming. 68 */ 69 70 /* 71 * Usually a message transits both the sender and receiver's conns as it 72 * flows to the receiver. In the loopback case, though, the receive path 73 * is handed the sending conn so the sense of the addresses is reversed. 74 */ 75 static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, 76 unsigned int hdr_off, unsigned int sg, 77 unsigned int off) 78 { 79 struct scatterlist *sgp = &rm->data.op_sg[sg]; 80 int ret = sizeof(struct rds_header) + 81 be32_to_cpu(rm->m_inc.i_hdr.h_len); 82 83 /* Do not send cong updates to loopback */ 84 if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { 85 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 86 ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off); 87 goto out; 88 } 89 90 BUG_ON(hdr_off || sg || off); 91 92 rds_inc_init(&rm->m_inc, conn, &conn->c_laddr); 93 /* For the embedded inc. Matching put is in loop_inc_free() */ 94 rds_message_addref(rm); 95 96 rds_recv_incoming(conn, &conn->c_laddr, &conn->c_faddr, &rm->m_inc, 97 GFP_KERNEL); 98 99 rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), 100 NULL); 101 102 rds_inc_put(&rm->m_inc); 103 out: 104 return ret; 105 } 106 107 /* 108 * See rds_loop_xmit(). Since our inc is embedded in the rm, we 109 * make sure the rm lives at least until the inc is done. 110 */ 111 static void rds_loop_inc_free(struct rds_incoming *inc) 112 { 113 struct rds_message *rm = container_of(inc, struct rds_message, m_inc); 114 115 rds_message_put(rm); 116 } 117 118 /* we need to at least give the thread something to succeed */ 119 static int rds_loop_recv_path(struct rds_conn_path *cp) 120 { 121 return 0; 122 } 123 124 struct rds_loop_connection { 125 struct list_head loop_node; 126 struct rds_connection *conn; 127 }; 128 129 /* 130 * Even the loopback transport needs to keep track of its connections, 131 * so it can call rds_conn_destroy() on them on exit. N.B. there are 132 * 1+ loopback addresses (127.*.*.*) so it's not a bug to have 133 * multiple loopback conns allocated, although rather useless. 134 */ 135 static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) 136 { 137 struct rds_loop_connection *lc; 138 unsigned long flags; 139 140 lc = kzalloc(sizeof(struct rds_loop_connection), gfp); 141 if (!lc) 142 return -ENOMEM; 143 144 INIT_LIST_HEAD(&lc->loop_node); 145 lc->conn = conn; 146 conn->c_transport_data = lc; 147 148 spin_lock_irqsave(&loop_conns_lock, flags); 149 list_add_tail(&lc->loop_node, &loop_conns); 150 spin_unlock_irqrestore(&loop_conns_lock, flags); 151 152 return 0; 153 } 154 155 static void rds_loop_conn_free(void *arg) 156 { 157 struct rds_loop_connection *lc = arg; 158 unsigned long flags; 159 160 rdsdebug("lc %p\n", lc); 161 spin_lock_irqsave(&loop_conns_lock, flags); 162 list_del(&lc->loop_node); 163 spin_unlock_irqrestore(&loop_conns_lock, flags); 164 kfree(lc); 165 } 166 167 static int rds_loop_conn_path_connect(struct rds_conn_path *cp) 168 { 169 rds_connect_complete(cp->cp_conn); 170 return 0; 171 } 172 173 static void rds_loop_conn_path_shutdown(struct rds_conn_path *cp) 174 { 175 } 176 177 void rds_loop_exit(void) 178 { 179 struct rds_loop_connection *lc, *_lc; 180 LIST_HEAD(tmp_list); 181 182 rds_loop_set_unloading(); 183 synchronize_rcu(); 184 /* avoid calling conn_destroy with irqs off */ 185 spin_lock_irq(&loop_conns_lock); 186 list_splice(&loop_conns, &tmp_list); 187 INIT_LIST_HEAD(&loop_conns); 188 spin_unlock_irq(&loop_conns_lock); 189 190 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 191 WARN_ON(lc->conn->c_passive); 192 rds_conn_destroy(lc->conn); 193 } 194 } 195 196 static void rds_loop_kill_conns(struct net *net) 197 { 198 struct rds_loop_connection *lc, *_lc; 199 LIST_HEAD(tmp_list); 200 201 spin_lock_irq(&loop_conns_lock); 202 list_for_each_entry_safe(lc, _lc, &loop_conns, loop_node) { 203 struct net *c_net = read_pnet(&lc->conn->c_net); 204 205 if (net != c_net) 206 continue; 207 list_move_tail(&lc->loop_node, &tmp_list); 208 } 209 spin_unlock_irq(&loop_conns_lock); 210 211 list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { 212 WARN_ON(lc->conn->c_passive); 213 rds_conn_destroy(lc->conn); 214 } 215 } 216 217 static void __net_exit rds_loop_exit_net(struct net *net) 218 { 219 rds_loop_kill_conns(net); 220 } 221 222 static struct pernet_operations rds_loop_net_ops = { 223 .exit = rds_loop_exit_net, 224 }; 225 226 int rds_loop_net_init(void) 227 { 228 return register_pernet_device(&rds_loop_net_ops); 229 } 230 231 void rds_loop_net_exit(void) 232 { 233 unregister_pernet_device(&rds_loop_net_ops); 234 } 235 236 /* 237 * This is missing .xmit_* because loop doesn't go through generic 238 * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and 239 * .laddr_check are missing because transport.c doesn't iterate over 240 * rds_loop_transport. 241 */ 242 struct rds_transport rds_loop_transport = { 243 .xmit = rds_loop_xmit, 244 .recv_path = rds_loop_recv_path, 245 .conn_alloc = rds_loop_conn_alloc, 246 .conn_free = rds_loop_conn_free, 247 .conn_path_connect = rds_loop_conn_path_connect, 248 .conn_path_shutdown = rds_loop_conn_path_shutdown, 249 .inc_copy_to_user = rds_message_inc_copy_to_user, 250 .inc_free = rds_loop_inc_free, 251 .t_name = "loopback", 252 .t_type = RDS_TRANS_LOOP, 253 .t_unloading = rds_loop_is_unloading, 254 }; 255