drivers/infiniband/core/netlink.c

   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
  45 static 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
  53 bool rdma_nl_chk_listeners(unsigned int group)
  54 {
  55         struct rdma_dev_net *rnet = rdma_net_to_dev_net(&init_net);
  56
  57         return netlink_has_listeners(rnet->nl_sock, group);
  58 }
  59 EXPORT_SYMBOL(rdma_nl_chk_listeners);
  60
  61 static 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]) ? true : false;
  79 }
  80
  81 static const struct rdma_nl_cbs *
  82 get_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(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(&rdma_nl_types[type].sem);
 100
 101                 request_module("rdma-netlink-subsys-%d", type);
 102
 103                 down_read(&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
 111 void 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 }
 121 EXPORT_SYMBOL(rdma_nl_register);
 122
 123 void rdma_nl_unregister(unsigned int index)
 124 {
 125         down_write(&rdma_nl_types[index].sem);
 126         rdma_nl_types[index].cb_table = NULL;
 127         up_write(&rdma_nl_types[index].sem);
 128 }
 129 EXPORT_SYMBOL(rdma_nl_unregister);
 130
 131 void *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, 0, seq, RDMA_NL_GET_TYPE(client, op), len, flags);
 135         if (!*nlh)
 136                 return NULL;
 137         return nlmsg_data(*nlh);
 138 }
 139 EXPORT_SYMBOL(ibnl_put_msg);
 140
 141 int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
 142                   int len, void *data, int type)
 143 {
 144         if (nla_put(skb, type, len, data)) {
 145                 nlmsg_cancel(skb, nlh);
 146                 return -EMSGSIZE;
 147         }
 148         return 0;
 149 }
 150 EXPORT_SYMBOL(ibnl_put_attr);
 151
 152 static 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(index, op))
 162                 return -EINVAL;
 163
 164         down_read(&rdma_nl_types[index].sem);
 165         cb_table = get_cb_table(skb, 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(skb->sk, skb, nlh, &c);
 191                 goto done;
 192         }
 193
 194         if (cb_table[op].doit)
 195                 err = cb_table[op].doit(skb, nlh, extack);
 196 done:
 197         up_read(&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  */
 207 static 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(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
 243 ack:
 244                 if (nlh->nlmsg_flags & NLM_F_ACK || err)
 245                         netlink_ack(skb, nlh, err, &extack);
 246
 247 skip:
 248                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 249                 if (msglen > skb->len)
 250                         msglen = skb->len;
 251                 skb_pull(skb, msglen);
 252         }
 253
 254         return 0;
 255 }
 256
 257 static void rdma_nl_rcv(struct sk_buff *skb)
 258 {
 259         rdma_nl_rcv_skb(skb, &rdma_nl_rcv_msg);
 260 }
 261
 262 int 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(rnet->nl_sock, skb, pid, MSG_DONTWAIT);
 268         return (err < 0) ? err : 0;
 269 }
 270 EXPORT_SYMBOL(rdma_nl_unicast);
 271
 272 int 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(rnet->nl_sock, skb, pid, 0);
 278         return (err < 0) ? err : 0;
 279 }
 280 EXPORT_SYMBOL(rdma_nl_unicast_wait);
 281
 282 int 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(rnet->nl_sock, skb, 0, group, flags);
 288 }
 289 EXPORT_SYMBOL(rdma_nl_multicast);
 290
 291 void 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
 299 void 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
 309 int rdma_nl_net_init(struct rdma_dev_net *rnet)
 310 {
 311         struct net *net = read_pnet(&rnet->net);
 312         struct netlink_kernel_cfg cfg = {
 313                 .input  = rdma_nl_rcv,
 314         };
 315         struct sock *nls;
 316
 317         nls = netlink_kernel_create(net, NETLINK_RDMA, &cfg);
 318         if (!nls)
 319                 return -ENOMEM;
 320
 321         nls->sk_sndtimeo = 10 * HZ;
 322         rnet->nl_sock = nls;
 323         return 0;
 324 }
 325
 326 void rdma_nl_net_exit(struct rdma_dev_net *rnet)
 327 {
 328         netlink_kernel_release(rnet->nl_sock);
 329 }
 330
 331 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_RDMA);