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 #include "core_priv.h"
  45
  46 static DEFINE_MUTEX(rdma_nl_mutex);
  47 static struct sock *nls;
  48 static struct {
  49         const struct rdma_nl_cbs   *cb_table;
  50 } rdma_nl_types[RDMA_NL_NUM_CLIENTS];
  51
  52 int rdma_nl_chk_listeners(unsigned int group)
  53 {
  54         return (netlink_has_listeners(nls, group)) ? 0 : -1;
  55 }
  56 EXPORT_SYMBOL(rdma_nl_chk_listeners);
  57
  58 static bool is_nl_msg_valid(unsigned int type, unsigned int op)
  59 {
  60         static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
  61                 [RDMA_NL_RDMA_CM] = RDMA_NL_RDMA_CM_NUM_OPS,
  62                 [RDMA_NL_IWCM] = RDMA_NL_IWPM_NUM_OPS,
  63                 [RDMA_NL_LS] = RDMA_NL_LS_NUM_OPS,
  64                 [RDMA_NL_NLDEV] = RDMA_NLDEV_NUM_OPS,
  65         };
  66
  67         /*
  68          * This BUILD_BUG_ON is intended to catch addition of new
  69          * RDMA netlink protocol without updating the array above.
  70          */
  71         BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);
  72
  73         if (type >= RDMA_NL_NUM_CLIENTS)
  74                 return false;
  75
  76         return (op < max_num_ops[type]) ? true : false;
  77 }
  78
  79 static bool is_nl_valid(unsigned int type, unsigned int op)
  80 {
  81         const struct rdma_nl_cbs *cb_table;
  82
  83         if (!is_nl_msg_valid(type, op))
  84                 return false;
  85
  86         cb_table = rdma_nl_types[type].cb_table;
  87 #ifdef CONFIG_MODULES
  88         if (!cb_table) {
  89                 mutex_unlock(&rdma_nl_mutex);
  90                 request_module("rdma-netlink-subsys-%d", type);
  91                 mutex_lock(&rdma_nl_mutex);
  92                 cb_table = rdma_nl_types[type].cb_table;
  93         }
  94 #endif
  95
  96         if (!cb_table || (!cb_table[op].dump && !cb_table[op].doit))
  97                 return false;
  98         return true;
  99 }
 100
 101 void rdma_nl_register(unsigned int index,
 102                       const struct rdma_nl_cbs cb_table[])
 103 {
 104         mutex_lock(&rdma_nl_mutex);
 105         if (!is_nl_msg_valid(index, 0)) {
 106                 /*
 107                  * All clients are not interesting in success/failure of
 108                  * this call. They want to see the print to error log and
 109                  * continue their initialization. Print warning for them,
 110                  * because it is programmer's error to be here.
 111                  */
 112                 mutex_unlock(&rdma_nl_mutex);
 113                 WARN(true,
 114                      "The not-valid %u index was supplied to RDMA netlink\n",
 115                      index);
 116                 return;
 117         }
 118
 119         if (rdma_nl_types[index].cb_table) {
 120                 mutex_unlock(&rdma_nl_mutex);
 121                 WARN(true,
 122                      "The %u index is already registered in RDMA netlink\n",
 123                      index);
 124                 return;
 125         }
 126
 127         rdma_nl_types[index].cb_table = cb_table;
 128         mutex_unlock(&rdma_nl_mutex);
 129 }
 130 EXPORT_SYMBOL(rdma_nl_register);
 131
 132 void rdma_nl_unregister(unsigned int index)
 133 {
 134         mutex_lock(&rdma_nl_mutex);
 135         rdma_nl_types[index].cb_table = NULL;
 136         mutex_unlock(&rdma_nl_mutex);
 137 }
 138 EXPORT_SYMBOL(rdma_nl_unregister);
 139
 140 void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
 141                    int len, int client, int op, int flags)
 142 {
 143         *nlh = nlmsg_put(skb, 0, seq, RDMA_NL_GET_TYPE(client, op), len, flags);
 144         if (!*nlh)
 145                 return NULL;
 146         return nlmsg_data(*nlh);
 147 }
 148 EXPORT_SYMBOL(ibnl_put_msg);
 149
 150 int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
 151                   int len, void *data, int type)
 152 {
 153         if (nla_put(skb, type, len, data)) {
 154                 nlmsg_cancel(skb, nlh);
 155                 return -EMSGSIZE;
 156         }
 157         return 0;
 158 }
 159 EXPORT_SYMBOL(ibnl_put_attr);
 160
 161 static int rdma_nl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 162                            struct netlink_ext_ack *extack)
 163 {
 164         int type = nlh->nlmsg_type;
 165         unsigned int index = RDMA_NL_GET_CLIENT(type);
 166         unsigned int op = RDMA_NL_GET_OP(type);
 167         const struct rdma_nl_cbs *cb_table;
 168
 169         if (!is_nl_valid(index, op))
 170                 return -EINVAL;
 171
 172         cb_table = rdma_nl_types[index].cb_table;
 173
 174         if ((cb_table[op].flags & RDMA_NL_ADMIN_PERM) &&
 175             !netlink_capable(skb, CAP_NET_ADMIN))
 176                 return -EPERM;
 177
 178         /*
 179          * LS responses overload the 0x100 (NLM_F_ROOT) flag.  Don't
 180          * mistakenly call the .dump() function.
 181          */
 182         if (index == RDMA_NL_LS) {
 183                 if (cb_table[op].doit)
 184                         return cb_table[op].doit(skb, nlh, extack);
 185                 return -EINVAL;
 186         }
 187         /* FIXME: Convert IWCM to properly handle doit callbacks */
 188         if ((nlh->nlmsg_flags & NLM_F_DUMP) || index == RDMA_NL_RDMA_CM ||
 189             index == RDMA_NL_IWCM) {
 190                 struct netlink_dump_control c = {
 191                         .dump = cb_table[op].dump,
 192                 };
 193                 if (c.dump)
 194                         return netlink_dump_start(nls, skb, nlh, &c);
 195                 return -EINVAL;
 196         }
 197
 198         if (cb_table[op].doit)
 199                 return cb_table[op].doit(skb, nlh, extack);
 200
 201         return 0;
 202 }
 203
 204 /*
 205  * This function is similar to netlink_rcv_skb with one exception:
 206  * It calls to the callback for the netlink messages without NLM_F_REQUEST
 207  * flag. These messages are intended for RDMA_NL_LS consumer, so it is allowed
 208  * for that consumer only.
 209  */
 210 static int rdma_nl_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 211                                                    struct nlmsghdr *,
 212                                                    struct netlink_ext_ack *))
 213 {
 214         struct netlink_ext_ack extack = {};
 215         struct nlmsghdr *nlh;
 216         int err;
 217
 218         while (skb->len >= nlmsg_total_size(0)) {
 219                 int msglen;
 220
 221                 nlh = nlmsg_hdr(skb);
 222                 err = 0;
 223
 224                 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
 225                         return 0;
 226
 227                 /*
 228                  * Generally speaking, the only requests are handled
 229                  * by the kernel, but RDMA_NL_LS is different, because it
 230                  * runs backward netlink scheme. Kernel initiates messages
 231                  * and waits for reply with data to keep pathrecord cache
 232                  * in sync.
 233                  */
 234                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST) &&
 235                     (RDMA_NL_GET_CLIENT(nlh->nlmsg_type) != RDMA_NL_LS))
 236                         goto ack;
 237
 238                 /* Skip control messages */
 239                 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
 240                         goto ack;
 241
 242                 err = cb(skb, nlh, &extack);
 243                 if (err == -EINTR)
 244                         goto skip;
 245
 246 ack:
 247                 if (nlh->nlmsg_flags & NLM_F_ACK || err)
 248                         netlink_ack(skb, nlh, err, &extack);
 249
 250 skip:
 251                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 252                 if (msglen > skb->len)
 253                         msglen = skb->len;
 254                 skb_pull(skb, msglen);
 255         }
 256
 257         return 0;
 258 }
 259
 260 static void rdma_nl_rcv(struct sk_buff *skb)
 261 {
 262         mutex_lock(&rdma_nl_mutex);
 263         rdma_nl_rcv_skb(skb, &rdma_nl_rcv_msg);
 264         mutex_unlock(&rdma_nl_mutex);
 265 }
 266
 267 int rdma_nl_unicast(struct sk_buff *skb, u32 pid)
 268 {
 269         int err;
 270
 271         err = netlink_unicast(nls, skb, pid, MSG_DONTWAIT);
 272         return (err < 0) ? err : 0;
 273 }
 274 EXPORT_SYMBOL(rdma_nl_unicast);
 275
 276 int rdma_nl_unicast_wait(struct sk_buff *skb, __u32 pid)
 277 {
 278         int err;
 279
 280         err = netlink_unicast(nls, skb, pid, 0);
 281         return (err < 0) ? err : 0;
 282 }
 283 EXPORT_SYMBOL(rdma_nl_unicast_wait);
 284
 285 int rdma_nl_multicast(struct sk_buff *skb, unsigned int group, gfp_t flags)
 286 {
 287         return nlmsg_multicast(nls, skb, 0, group, flags);
 288 }
 289 EXPORT_SYMBOL(rdma_nl_multicast);
 290
 291 int __init rdma_nl_init(void)
 292 {
 293         struct netlink_kernel_cfg cfg = {
 294                 .input  = rdma_nl_rcv,
 295         };
 296
 297         nls = netlink_kernel_create(&init_net, NETLINK_RDMA, &cfg);
 298         if (!nls)
 299                 return -ENOMEM;
 300
 301         nls->sk_sndtimeo = 10 * HZ;
 302         return 0;
 303 }
 304
 305 void rdma_nl_exit(void)
 306 {
 307         int idx;
 308
 309         for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
 310                 rdma_nl_unregister(idx);
 311
 312         netlink_kernel_release(nls);
 313 }
 314
 315 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_RDMA);