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/sock.h>
  40 #include <rdma/rdma_netlink.h>
  41 #include <linux/module.h>
  42 #include "core_priv.h"
  43
  44 static DEFINE_MUTEX(rdma_nl_mutex);
  45 static struct sock *nls;
  46 static struct {
  47         const struct rdma_nl_cbs   *cb_table;
  48 } rdma_nl_types[RDMA_NL_NUM_CLIENTS];
  49
  50 int rdma_nl_chk_listeners(unsigned int group)
  51 {
  52         return (netlink_has_listeners(nls, group)) ? 0 : -1;
  53 }
  54 EXPORT_SYMBOL(rdma_nl_chk_listeners);
  55
  56 static bool is_nl_msg_valid(unsigned int type, unsigned int op)
  57 {
  58         static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
  59                 [RDMA_NL_RDMA_CM] = RDMA_NL_RDMA_CM_NUM_OPS,
  60                 [RDMA_NL_IWCM] = RDMA_NL_IWPM_NUM_OPS,
  61                 [RDMA_NL_LS] = RDMA_NL_LS_NUM_OPS,
  62                 [RDMA_NL_NLDEV] = RDMA_NLDEV_NUM_OPS,
  63         };
  64
  65         /*
  66          * This BUILD_BUG_ON is intended to catch addition of new
  67          * RDMA netlink protocol without updating the array above.
  68          */
  69         BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);
  70
  71         if (type >= RDMA_NL_NUM_CLIENTS)
  72                 return false;
  73
  74         return (op < max_num_ops[type]) ? true : false;
  75 }
  76
  77 static bool is_nl_valid(unsigned int type, unsigned int op)
  78 {
  79         const struct rdma_nl_cbs *cb_table;
  80
  81         if (!is_nl_msg_valid(type, op))
  82                 return false;
  83
  84         if (!rdma_nl_types[type].cb_table) {
  85                 mutex_unlock(&rdma_nl_mutex);
  86                 request_module("rdma-netlink-subsys-%d", type);
  87                 mutex_lock(&rdma_nl_mutex);
  88         }
  89
  90         cb_table = rdma_nl_types[type].cb_table;
  91
  92         if (!cb_table || (!cb_table[op].dump && !cb_table[op].doit))
  93                 return false;
  94         return true;
  95 }
  96
  97 void rdma_nl_register(unsigned int index,
  98                       const struct rdma_nl_cbs cb_table[])
  99 {
 100         mutex_lock(&rdma_nl_mutex);
 101         if (!is_nl_msg_valid(index, 0)) {
 102                 /*
 103                  * All clients are not interesting in success/failure of
 104                  * this call. They want to see the print to error log and
 105                  * continue their initialization. Print warning for them,
 106                  * because it is programmer's error to be here.
 107                  */
 108                 mutex_unlock(&rdma_nl_mutex);
 109                 WARN(true,
 110                      "The not-valid %u index was supplied to RDMA netlink\n",
 111                      index);
 112                 return;
 113         }
 114
 115         if (rdma_nl_types[index].cb_table) {
 116                 mutex_unlock(&rdma_nl_mutex);
 117                 WARN(true,
 118                      "The %u index is already registered in RDMA netlink\n",
 119                      index);
 120                 return;
 121         }
 122
 123         rdma_nl_types[index].cb_table = cb_table;
 124         mutex_unlock(&rdma_nl_mutex);
 125 }
 126 EXPORT_SYMBOL(rdma_nl_register);
 127
 128 void rdma_nl_unregister(unsigned int index)
 129 {
 130         mutex_lock(&rdma_nl_mutex);
 131         rdma_nl_types[index].cb_table = NULL;
 132         mutex_unlock(&rdma_nl_mutex);
 133 }
 134 EXPORT_SYMBOL(rdma_nl_unregister);
 135
 136 void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
 137                    int len, int client, int op, int flags)
 138 {
 139         *nlh = nlmsg_put(skb, 0, seq, RDMA_NL_GET_TYPE(client, op), len, flags);
 140         if (!*nlh)
 141                 return NULL;
 142         return nlmsg_data(*nlh);
 143 }
 144 EXPORT_SYMBOL(ibnl_put_msg);
 145
 146 int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
 147                   int len, void *data, int type)
 148 {
 149         if (nla_put(skb, type, len, data)) {
 150                 nlmsg_cancel(skb, nlh);
 151                 return -EMSGSIZE;
 152         }
 153         return 0;
 154 }
 155 EXPORT_SYMBOL(ibnl_put_attr);
 156
 157 static int rdma_nl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 158                            struct netlink_ext_ack *extack)
 159 {
 160         int type = nlh->nlmsg_type;
 161         unsigned int index = RDMA_NL_GET_CLIENT(type);
 162         unsigned int op = RDMA_NL_GET_OP(type);
 163         const struct rdma_nl_cbs *cb_table;
 164
 165         if (!is_nl_valid(index, op))
 166                 return -EINVAL;
 167
 168         cb_table = rdma_nl_types[index].cb_table;
 169
 170         if ((cb_table[op].flags & RDMA_NL_ADMIN_PERM) &&
 171             !netlink_capable(skb, CAP_NET_ADMIN))
 172                 return -EPERM;
 173
 174         /*
 175          * LS responses overload the 0x100 (NLM_F_ROOT) flag.  Don't
 176          * mistakenly call the .dump() function.
 177          */
 178         if (index == RDMA_NL_LS) {
 179                 if (cb_table[op].doit)
 180                         return cb_table[op].doit(skb, nlh, extack);
 181                 return -EINVAL;
 182         }
 183         /* FIXME: Convert IWCM to properly handle doit callbacks */
 184         if ((nlh->nlmsg_flags & NLM_F_DUMP) || index == RDMA_NL_RDMA_CM ||
 185             index == RDMA_NL_IWCM) {
 186                 struct netlink_dump_control c = {
 187                         .dump = cb_table[op].dump,
 188                 };
 189                 if (c.dump)
 190                         return netlink_dump_start(nls, skb, nlh, &c);
 191                 return -EINVAL;
 192         }
 193
 194         if (cb_table[op].doit)
 195                 return cb_table[op].doit(skb, nlh, extack);
 196
 197         return 0;
 198 }
 199
 200 /*
 201  * This function is similar to netlink_rcv_skb with one exception:
 202  * It calls to the callback for the netlink messages without NLM_F_REQUEST
 203  * flag. These messages are intended for RDMA_NL_LS consumer, so it is allowed
 204  * for that consumer only.
 205  */
 206 static int rdma_nl_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 207                                                    struct nlmsghdr *,
 208                                                    struct netlink_ext_ack *))
 209 {
 210         struct netlink_ext_ack extack = {};
 211         struct nlmsghdr *nlh;
 212         int err;
 213
 214         while (skb->len >= nlmsg_total_size(0)) {
 215                 int msglen;
 216
 217                 nlh = nlmsg_hdr(skb);
 218                 err = 0;
 219
 220                 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
 221                         return 0;
 222
 223                 /*
 224                  * Generally speaking, the only requests are handled
 225                  * by the kernel, but RDMA_NL_LS is different, because it
 226                  * runs backward netlink scheme. Kernel initiates messages
 227                  * and waits for reply with data to keep pathrecord cache
 228                  * in sync.
 229                  */
 230                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST) &&
 231                     (RDMA_NL_GET_CLIENT(nlh->nlmsg_type) != RDMA_NL_LS))
 232                         goto ack;
 233
 234                 /* Skip control messages */
 235                 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
 236                         goto ack;
 237
 238                 err = cb(skb, nlh, &extack);
 239                 if (err == -EINTR)
 240                         goto skip;
 241
 242 ack:
 243                 if (nlh->nlmsg_flags & NLM_F_ACK || err)
 244                         netlink_ack(skb, nlh, err, &extack);
 245
 246 skip:
 247                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 248                 if (msglen > skb->len)
 249                         msglen = skb->len;
 250                 skb_pull(skb, msglen);
 251         }
 252
 253         return 0;
 254 }
 255
 256 static void rdma_nl_rcv(struct sk_buff *skb)
 257 {
 258         mutex_lock(&rdma_nl_mutex);
 259         rdma_nl_rcv_skb(skb, &rdma_nl_rcv_msg);
 260         mutex_unlock(&rdma_nl_mutex);
 261 }
 262
 263 int rdma_nl_unicast(struct sk_buff *skb, u32 pid)
 264 {
 265         int err;
 266
 267         err = netlink_unicast(nls, 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 sk_buff *skb, __u32 pid)
 273 {
 274         int err;
 275
 276         err = netlink_unicast(nls, skb, pid, 0);
 277         return (err < 0) ? err : 0;
 278 }
 279 EXPORT_SYMBOL(rdma_nl_unicast_wait);
 280
 281 int rdma_nl_multicast(struct sk_buff *skb, unsigned int group, gfp_t flags)
 282 {
 283         return nlmsg_multicast(nls, skb, 0, group, flags);
 284 }
 285 EXPORT_SYMBOL(rdma_nl_multicast);
 286
 287 int __init rdma_nl_init(void)
 288 {
 289         struct netlink_kernel_cfg cfg = {
 290                 .input  = rdma_nl_rcv,
 291         };
 292
 293         nls = netlink_kernel_create(&init_net, NETLINK_RDMA, &cfg);
 294         if (!nls)
 295                 return -ENOMEM;
 296
 297         nls->sk_sndtimeo = 10 * HZ;
 298         return 0;
 299 }
 300
 301 void rdma_nl_exit(void)
 302 {
 303         int idx;
 304
 305         for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
 306                 rdma_nl_unregister(idx);
 307
 308         netlink_kernel_release(nls);
 309 }
 310
 311 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_RDMA);