net/sunrpc/pmap_clnt.c

   1 /*
   2  * linux/net/sunrpc/pmap_clnt.c
   3  *
   4  * In-kernel RPC portmapper client.
   5  *
   6  * Portmapper supports version 2 of the rpcbind protocol (RFC 1833).
   7  *
   8  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/socket.h>
  13 #include <linux/kernel.h>
  14 #include <linux/errno.h>
  15 #include <linux/uio.h>
  16 #include <linux/in.h>
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/sunrpc/sched.h>
  19
  20 #ifdef RPC_DEBUG
  21 # define RPCDBG_FACILITY        RPCDBG_PMAP
  22 #endif
  23
  24 #define PMAP_SET                1
  25 #define PMAP_UNSET              2
  26 #define PMAP_GETPORT            3
  27
  28 struct portmap_args {
  29         u32                     pm_prog;
  30         u32                     pm_vers;
  31         u32                     pm_prot;
  32         unsigned short          pm_port;
  33         struct rpc_xprt *       pm_xprt;
  34 };
  35
  36 static struct rpc_procinfo      pmap_procedures[];
  37 static struct rpc_clnt *        pmap_create(char *, struct sockaddr_in *, int, int);
  38 static void                     pmap_getport_done(struct rpc_task *, void *);
  39 static struct rpc_program       pmap_program;
  40
  41 static void pmap_getport_prepare(struct rpc_task *task, void *calldata)
  42 {
  43         struct portmap_args *map = calldata;
  44         struct rpc_message msg = {
  45                 .rpc_proc       = &pmap_procedures[PMAP_GETPORT],
  46                 .rpc_argp       = map,
  47                 .rpc_resp       = &map->pm_port,
  48         };
  49
  50         rpc_call_setup(task, &msg, 0);
  51 }
  52
  53 static inline struct portmap_args *pmap_map_alloc(void)
  54 {
  55         return kmalloc(sizeof(struct portmap_args), GFP_NOFS);
  56 }
  57
  58 static inline void pmap_map_free(struct portmap_args *map)
  59 {
  60         kfree(map);
  61 }
  62
  63 static void pmap_map_release(void *data)
  64 {
  65         pmap_map_free(data);
  66 }
  67
  68 static const struct rpc_call_ops pmap_getport_ops = {
  69         .rpc_call_prepare       = pmap_getport_prepare,
  70         .rpc_call_done          = pmap_getport_done,
  71         .rpc_release            = pmap_map_release,
  72 };
  73
  74 static inline void pmap_wake_portmap_waiters(struct rpc_xprt *xprt, int status)
  75 {
  76         xprt_clear_binding(xprt);
  77         rpc_wake_up_status(&xprt->binding, status);
  78 }
  79
  80 /**
  81  * rpc_getport - obtain the port for a given RPC service on a given host
  82  * @task: task that is waiting for portmapper request
  83  *
  84  * This one can be called for an ongoing RPC request, and can be used in
  85  * an async (rpciod) context.
  86  */
  87 void rpc_getport(struct rpc_task *task)
  88 {
  89         struct rpc_clnt *clnt = task->tk_client;
  90         struct rpc_xprt *xprt = task->tk_xprt;
  91         struct sockaddr_in addr;
  92         struct portmap_args *map;
  93         struct rpc_clnt *pmap_clnt;
  94         struct rpc_task *child;
  95         int status;
  96
  97         dprintk("RPC: %4d rpc_getport(%s, %u, %u, %d)\n",
  98                         task->tk_pid, clnt->cl_server,
  99                         clnt->cl_prog, clnt->cl_vers, xprt->prot);
 100
 101         /* Autobind on cloned rpc clients is discouraged */
 102         BUG_ON(clnt->cl_parent != clnt);
 103
 104         /* Put self on queue before sending rpcbind request, in case
 105          * pmap_getport_done completes before we return from rpc_run_task */
 106         rpc_sleep_on(&xprt->binding, task, NULL, NULL);
 107
 108         status = -EACCES;               /* tell caller to check again */
 109         if (xprt_test_and_set_binding(xprt))
 110                 goto bailout_nofree;
 111
 112         /* Someone else may have bound if we slept */
 113         status = 0;
 114         if (xprt_bound(xprt))
 115                 goto bailout_nofree;
 116
 117         status = -ENOMEM;
 118         map = pmap_map_alloc();
 119         if (!map)
 120                 goto bailout_nofree;
 121         map->pm_prog = clnt->cl_prog;
 122         map->pm_vers = clnt->cl_vers;
 123         map->pm_prot = xprt->prot;
 124         map->pm_port = 0;
 125         map->pm_xprt = xprt_get(xprt);
 126
 127         rpc_peeraddr(clnt, (struct sockaddr *) &addr, sizeof(addr));
 128         pmap_clnt = pmap_create(clnt->cl_server, &addr, map->pm_prot, 0);
 129         status = PTR_ERR(pmap_clnt);
 130         if (IS_ERR(pmap_clnt))
 131                 goto bailout;
 132
 133         status = -EIO;
 134         child = rpc_run_task(pmap_clnt, RPC_TASK_ASYNC, &pmap_getport_ops, map);
 135         if (IS_ERR(child))
 136                 goto bailout;
 137         rpc_release_task(child);
 138
 139         task->tk_xprt->stat.bind_count++;
 140         return;
 141
 142 bailout:
 143         pmap_map_free(map);
 144         xprt_put(xprt);
 145 bailout_nofree:
 146         task->tk_status = status;
 147         pmap_wake_portmap_waiters(xprt, status);
 148 }
 149
 150 #ifdef CONFIG_ROOT_NFS
 151 /**
 152  * rpc_getport_external - obtain the port for a given RPC service on a given host
 153  * @sin: address of remote peer
 154  * @prog: RPC program number to bind
 155  * @vers: RPC version number to bind
 156  * @prot: transport protocol to use to make this request
 157  *
 158  * This one is called from outside the RPC client in a synchronous task context.
 159  */
 160 int rpc_getport_external(struct sockaddr_in *sin, __u32 prog, __u32 vers, int prot)
 161 {
 162         struct portmap_args map = {
 163                 .pm_prog        = prog,
 164                 .pm_vers        = vers,
 165                 .pm_prot        = prot,
 166                 .pm_port        = 0
 167         };
 168         struct rpc_message msg = {
 169                 .rpc_proc       = &pmap_procedures[PMAP_GETPORT],
 170                 .rpc_argp       = &map,
 171                 .rpc_resp       = &map.pm_port,
 172         };
 173         struct rpc_clnt *pmap_clnt;
 174         char            hostname[32];
 175         int             status;
 176
 177         dprintk("RPC:      rpc_getport_external(%u.%u.%u.%u, %u, %u, %d)\n",
 178                         NIPQUAD(sin->sin_addr.s_addr), prog, vers, prot);
 179
 180         sprintf(hostname, "%u.%u.%u.%u", NIPQUAD(sin->sin_addr.s_addr));
 181         pmap_clnt = pmap_create(hostname, sin, prot, 0);
 182         if (IS_ERR(pmap_clnt))
 183                 return PTR_ERR(pmap_clnt);
 184
 185         /* Setup the call info struct */
 186         status = rpc_call_sync(pmap_clnt, &msg, 0);
 187
 188         if (status >= 0) {
 189                 if (map.pm_port != 0)
 190                         return map.pm_port;
 191                 status = -EACCES;
 192         }
 193         return status;
 194 }
 195 #endif
 196
 197 /*
 198  * Portmapper child task invokes this callback via tk_exit.
 199  */
 200 static void pmap_getport_done(struct rpc_task *child, void *data)
 201 {
 202         struct portmap_args *map = data;
 203         struct rpc_xprt *xprt = map->pm_xprt;
 204         int status = child->tk_status;
 205
 206         if (status < 0) {
 207                 /* Portmapper not available */
 208                 xprt->ops->set_port(xprt, 0);
 209         } else if (map->pm_port == 0) {
 210                 /* Requested RPC service wasn't registered */
 211                 xprt->ops->set_port(xprt, 0);
 212                 status = -EACCES;
 213         } else {
 214                 /* Succeeded */
 215                 xprt->ops->set_port(xprt, map->pm_port);
 216                 xprt_set_bound(xprt);
 217                 status = 0;
 218         }
 219
 220         dprintk("RPC: %4d pmap_getport_done(status %d, port %u)\n",
 221                         child->tk_pid, status, map->pm_port);
 222
 223         pmap_wake_portmap_waiters(xprt, status);
 224         xprt_put(xprt);
 225 }
 226
 227 /**
 228  * rpc_register - set or unset a port registration with the local portmapper
 229  * @prog: RPC program number to bind
 230  * @vers: RPC version number to bind
 231  * @prot: transport protocol to use to make this request
 232  * @port: port value to register
 233  * @okay: result code
 234  *
 235  * port == 0 means unregister, port != 0 means register.
 236  */
 237 int rpc_register(u32 prog, u32 vers, int prot, unsigned short port, int *okay)
 238 {
 239         struct sockaddr_in      sin = {
 240                 .sin_family     = AF_INET,
 241                 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
 242         };
 243         struct portmap_args     map = {
 244                 .pm_prog        = prog,
 245                 .pm_vers        = vers,
 246                 .pm_prot        = prot,
 247                 .pm_port        = port,
 248         };
 249         struct rpc_message msg = {
 250                 .rpc_proc       = &pmap_procedures[port ? PMAP_SET : PMAP_UNSET],
 251                 .rpc_argp       = &map,
 252                 .rpc_resp       = okay,
 253         };
 254         struct rpc_clnt         *pmap_clnt;
 255         int error = 0;
 256
 257         dprintk("RPC: registering (%u, %u, %d, %u) with portmapper.\n",
 258                         prog, vers, prot, port);
 259
 260         pmap_clnt = pmap_create("localhost", &sin, IPPROTO_UDP, 1);
 261         if (IS_ERR(pmap_clnt)) {
 262                 error = PTR_ERR(pmap_clnt);
 263                 dprintk("RPC: couldn't create pmap client. Error = %d\n", error);
 264                 return error;
 265         }
 266
 267         error = rpc_call_sync(pmap_clnt, &msg, 0);
 268
 269         if (error < 0) {
 270                 printk(KERN_WARNING
 271                         "RPC: failed to contact portmap (errno %d).\n",
 272                         error);
 273         }
 274         dprintk("RPC: registration status %d/%d\n", error, *okay);
 275
 276         /* Client deleted automatically because cl_oneshot == 1 */
 277         return error;
 278 }
 279
 280 static struct rpc_clnt *pmap_create(char *hostname, struct sockaddr_in *srvaddr, int proto, int privileged)
 281 {
 282         struct rpc_create_args args = {
 283                 .protocol       = proto,
 284                 .address        = (struct sockaddr *)srvaddr,
 285                 .addrsize       = sizeof(*srvaddr),
 286                 .servername     = hostname,
 287                 .program        = &pmap_program,
 288                 .version        = RPC_PMAP_VERSION,
 289                 .authflavor     = RPC_AUTH_UNIX,
 290                 .flags          = (RPC_CLNT_CREATE_ONESHOT |
 291                                    RPC_CLNT_CREATE_NOPING),
 292         };
 293
 294         srvaddr->sin_port = htons(RPC_PMAP_PORT);
 295         if (!privileged)
 296                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 297         return rpc_create(&args);
 298 }
 299
 300 /*
 301  * XDR encode/decode functions for PMAP
 302  */
 303 static int xdr_encode_mapping(struct rpc_rqst *req, __be32 *p, struct portmap_args *map)
 304 {
 305         dprintk("RPC: xdr_encode_mapping(%u, %u, %u, %u)\n",
 306                 map->pm_prog, map->pm_vers, map->pm_prot, map->pm_port);
 307         *p++ = htonl(map->pm_prog);
 308         *p++ = htonl(map->pm_vers);
 309         *p++ = htonl(map->pm_prot);
 310         *p++ = htonl(map->pm_port);
 311
 312         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 313         return 0;
 314 }
 315
 316 static int xdr_decode_port(struct rpc_rqst *req, __be32 *p, unsigned short *portp)
 317 {
 318         *portp = (unsigned short) ntohl(*p++);
 319         return 0;
 320 }
 321
 322 static int xdr_decode_bool(struct rpc_rqst *req, __be32 *p, unsigned int *boolp)
 323 {
 324         *boolp = (unsigned int) ntohl(*p++);
 325         return 0;
 326 }
 327
 328 static struct rpc_procinfo      pmap_procedures[] = {
 329 [PMAP_SET] = {
 330           .p_proc               = PMAP_SET,
 331           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 332           .p_decode             = (kxdrproc_t) xdr_decode_bool,
 333           .p_bufsiz             = 4,
 334           .p_count              = 1,
 335           .p_statidx            = PMAP_SET,
 336           .p_name               = "SET",
 337         },
 338 [PMAP_UNSET] = {
 339           .p_proc               = PMAP_UNSET,
 340           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 341           .p_decode             = (kxdrproc_t) xdr_decode_bool,
 342           .p_bufsiz             = 4,
 343           .p_count              = 1,
 344           .p_statidx            = PMAP_UNSET,
 345           .p_name               = "UNSET",
 346         },
 347 [PMAP_GETPORT] = {
 348           .p_proc               = PMAP_GETPORT,
 349           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 350           .p_decode             = (kxdrproc_t) xdr_decode_port,
 351           .p_bufsiz             = 4,
 352           .p_count              = 1,
 353           .p_statidx            = PMAP_GETPORT,
 354           .p_name               = "GETPORT",
 355         },
 356 };
 357
 358 static struct rpc_version       pmap_version2 = {
 359         .number         = 2,
 360         .nrprocs        = 4,
 361         .procs          = pmap_procedures
 362 };
 363
 364 static struct rpc_version *     pmap_version[] = {
 365         NULL,
 366         NULL,
 367         &pmap_version2
 368 };
 369
 370 static struct rpc_stat          pmap_stats;
 371
 372 static struct rpc_program       pmap_program = {
 373         .name           = "portmap",
 374         .number         = RPC_PMAP_PROGRAM,
 375         .nrvers         = ARRAY_SIZE(pmap_version),
 376         .version        = pmap_version,
 377         .stats          = &pmap_stats,
 378 };