1/*
2 * Copyright (c) 2017 Mellanox Technologies Inc. All rights reserved.
3 * Copyright (c) 2010 Voltaire Inc. All rights reserved.
4 *
5 * This software is available to you under a choice of one of two
6 * licenses. You may choose to be licensed under the terms of the GNU
7 * General Public License (GPL) Version 2, available from the file
8 * COPYING in the main directory of this source tree, or the
9 * OpenIB.org BSD license below:
10 *
11 * Redistribution and use in source and binary forms, with or
12 * without modification, are permitted provided that the following
13 * conditions are met:
14 *
15 * - Redistributions of source code must retain the above
16 * copyright notice, this list of conditions and the following
17 * disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials
22 * provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
35
36#include <linux/export.h>
37#include <net/netlink.h>
38#include <net/net_namespace.h>
39#include <net/netns/generic.h>
40#include <net/sock.h>
41#include <rdma/rdma_netlink.h>
42#include <linux/module.h>
43#include "core_priv.h"
44
45static struct {
46 const struct rdma_nl_cbs *cb_table;
47 /* Synchronizes between ongoing netlink commands and netlink client
48 * unregistration.
49 */
50 struct rw_semaphore sem;
51} rdma_nl_types[RDMA_NL_NUM_CLIENTS];
52
53bool rdma_nl_chk_listeners(unsigned int group)
54{
55 struct rdma_dev_net *rnet = rdma_net_to_dev_net(net: &init_net);
56
57 return netlink_has_listeners(sk: rnet->nl_sock, group);
58}
59EXPORT_SYMBOL(rdma_nl_chk_listeners);
60
61static bool is_nl_msg_valid(unsigned int type, unsigned int op)
62{
63 static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
64 [RDMA_NL_IWCM] = RDMA_NL_IWPM_NUM_OPS,
65 [RDMA_NL_LS] = RDMA_NL_LS_NUM_OPS,
66 [RDMA_NL_NLDEV] = RDMA_NLDEV_NUM_OPS,
67 };
68
69 /*
70 * This BUILD_BUG_ON is intended to catch addition of new
71 * RDMA netlink protocol without updating the array above.
72 */
73 BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);
74
75 if (type >= RDMA_NL_NUM_CLIENTS)
76 return false;
77
78 return op < max_num_ops[type];
79}
80
81static const struct rdma_nl_cbs *
82get_cb_table(const struct sk_buff *skb, unsigned int type, unsigned int op)
83{
84 const struct rdma_nl_cbs *cb_table;
85
86 /*
87 * Currently only NLDEV client is supporting netlink commands in
88 * non init_net net namespace.
89 */
90 if (sock_net(sk: skb->sk) != &init_net && type != RDMA_NL_NLDEV)
91 return NULL;
92
93 cb_table = READ_ONCE(rdma_nl_types[type].cb_table);
94 if (!cb_table) {
95 /*
96 * Didn't get valid reference of the table, attempt module
97 * load once.
98 */
99 up_read(sem: &rdma_nl_types[type].sem);
100
101 request_module("rdma-netlink-subsys-%u", type);
102
103 down_read(sem: &rdma_nl_types[type].sem);
104 cb_table = READ_ONCE(rdma_nl_types[type].cb_table);
105 }
106 if (!cb_table || (!cb_table[op].dump && !cb_table[op].doit))
107 return NULL;
108 return cb_table;
109}
110
111void rdma_nl_register(unsigned int index,
112 const struct rdma_nl_cbs cb_table[])
113{
114 if (WARN_ON(!is_nl_msg_valid(index, 0)) ||
115 WARN_ON(READ_ONCE(rdma_nl_types[index].cb_table)))
116 return;
117
118 /* Pairs with the READ_ONCE in is_nl_valid() */
119 smp_store_release(&rdma_nl_types[index].cb_table, cb_table);
120}
121EXPORT_SYMBOL(rdma_nl_register);
122
123void rdma_nl_unregister(unsigned int index)
124{
125 down_write(sem: &rdma_nl_types[index].sem);
126 rdma_nl_types[index].cb_table = NULL;
127 up_write(sem: &rdma_nl_types[index].sem);
128}
129EXPORT_SYMBOL(rdma_nl_unregister);
130
131void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
132 int len, int client, int op, int flags)
133{
134 *nlh = nlmsg_put(skb, portid: 0, seq, RDMA_NL_GET_TYPE(client, op), payload: len, flags);
135 if (!*nlh)
136 return NULL;
137 return nlmsg_data(nlh: *nlh);
138}
139EXPORT_SYMBOL(ibnl_put_msg);
140
141int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
142 int len, void *data, int type)
143{
144 if (nla_put(skb, attrtype: type, attrlen: len, data)) {
145 nlmsg_cancel(skb, nlh);
146 return -EMSGSIZE;
147 }
148 return 0;
149}
150EXPORT_SYMBOL(ibnl_put_attr);
151
152static int rdma_nl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
153 struct netlink_ext_ack *extack)
154{
155 int type = nlh->nlmsg_type;
156 unsigned int index = RDMA_NL_GET_CLIENT(type);
157 unsigned int op = RDMA_NL_GET_OP(type);
158 const struct rdma_nl_cbs *cb_table;
159 int err = -EINVAL;
160
161 if (!is_nl_msg_valid(type: index, op))
162 return -EINVAL;
163
164 down_read(sem: &rdma_nl_types[index].sem);
165 cb_table = get_cb_table(skb, type: index, op);
166 if (!cb_table)
167 goto done;
168
169 if ((cb_table[op].flags & RDMA_NL_ADMIN_PERM) &&
170 !netlink_capable(skb, CAP_NET_ADMIN)) {
171 err = -EPERM;
172 goto done;
173 }
174
175 /*
176 * LS responses overload the 0x100 (NLM_F_ROOT) flag. Don't
177 * mistakenly call the .dump() function.
178 */
179 if (index == RDMA_NL_LS) {
180 if (cb_table[op].doit)
181 err = cb_table[op].doit(skb, nlh, extack);
182 goto done;
183 }
184 /* FIXME: Convert IWCM to properly handle doit callbacks */
185 if ((nlh->nlmsg_flags & NLM_F_DUMP) || index == RDMA_NL_IWCM) {
186 struct netlink_dump_control c = {
187 .dump = cb_table[op].dump,
188 };
189 if (c.dump)
190 err = netlink_dump_start(ssk: skb->sk, skb, nlh, control: &c);
191 goto done;
192 }
193
194 if (cb_table[op].doit)
195 err = cb_table[op].doit(skb, nlh, extack);
196done:
197 up_read(sem: &rdma_nl_types[index].sem);
198 return err;
199}
200
201/*
202 * This function is similar to netlink_rcv_skb with one exception:
203 * It calls to the callback for the netlink messages without NLM_F_REQUEST
204 * flag. These messages are intended for RDMA_NL_LS consumer, so it is allowed
205 * for that consumer only.
206 */
207static int rdma_nl_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
208 struct nlmsghdr *,
209 struct netlink_ext_ack *))
210{
211 struct netlink_ext_ack extack = {};
212 struct nlmsghdr *nlh;
213 int err;
214
215 while (skb->len >= nlmsg_total_size(payload: 0)) {
216 int msglen;
217
218 nlh = nlmsg_hdr(skb);
219 err = 0;
220
221 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
222 return 0;
223
224 /*
225 * Generally speaking, the only requests are handled
226 * by the kernel, but RDMA_NL_LS is different, because it
227 * runs backward netlink scheme. Kernel initiates messages
228 * and waits for reply with data to keep pathrecord cache
229 * in sync.
230 */
231 if (!(nlh->nlmsg_flags & NLM_F_REQUEST) &&
232 (RDMA_NL_GET_CLIENT(nlh->nlmsg_type) != RDMA_NL_LS))
233 goto ack;
234
235 /* Skip control messages */
236 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
237 goto ack;
238
239 err = cb(skb, nlh, &extack);
240 if (err == -EINTR)
241 goto skip;
242
243ack:
244 if (nlh->nlmsg_flags & NLM_F_ACK || err)
245 netlink_ack(in_skb: skb, nlh, err, extack: &extack);
246
247skip:
248 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
249 if (msglen > skb->len)
250 msglen = skb->len;
251 skb_pull(skb, len: msglen);
252 }
253
254 return 0;
255}
256
257static void rdma_nl_rcv(struct sk_buff *skb)
258{
259 rdma_nl_rcv_skb(skb, cb: &rdma_nl_rcv_msg);
260}
261
262int rdma_nl_unicast(struct net *net, struct sk_buff *skb, u32 pid)
263{
264 struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
265 int err;
266
267 err = netlink_unicast(ssk: rnet->nl_sock, skb, portid: pid, MSG_DONTWAIT);
268 return (err < 0) ? err : 0;
269}
270EXPORT_SYMBOL(rdma_nl_unicast);
271
272int rdma_nl_unicast_wait(struct net *net, struct sk_buff *skb, __u32 pid)
273{
274 struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
275 int err;
276
277 err = netlink_unicast(ssk: rnet->nl_sock, skb, portid: pid, nonblock: 0);
278 return (err < 0) ? err : 0;
279}
280EXPORT_SYMBOL(rdma_nl_unicast_wait);
281
282int rdma_nl_multicast(struct net *net, struct sk_buff *skb,
283 unsigned int group, gfp_t flags)
284{
285 struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
286
287 return nlmsg_multicast(sk: rnet->nl_sock, skb, portid: 0, group, flags);
288}
289EXPORT_SYMBOL(rdma_nl_multicast);
290
291void rdma_nl_init(void)
292{
293 int idx;
294
295 for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
296 init_rwsem(&rdma_nl_types[idx].sem);
297}
298
299void rdma_nl_exit(void)
300{
301 int idx;
302
303 for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
304 WARN(rdma_nl_types[idx].cb_table,
305 "Netlink client %d wasn't released prior to unloading %s\n",
306 idx, KBUILD_MODNAME);
307}
308
309int rdma_nl_net_init(struct rdma_dev_net *rnet)
310{
311 struct net *net = read_pnet(pnet: &rnet->net);
312 struct netlink_kernel_cfg cfg = {
313 .input = rdma_nl_rcv,
314 .flags = NL_CFG_F_NONROOT_RECV,
315 };
316 struct sock *nls;
317
318 nls = netlink_kernel_create(net, NETLINK_RDMA, cfg: &cfg);
319 if (!nls)
320 return -ENOMEM;
321
322 nls->sk_sndtimeo = 10 * HZ;
323 rnet->nl_sock = nls;
324 return 0;
325}
326
327void rdma_nl_net_exit(struct rdma_dev_net *rnet)
328{
329 netlink_kernel_release(sk: rnet->nl_sock);
330}
331
332MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_RDMA);
333

source code of linux/drivers/infiniband/core/netlink.c