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_task *       pm_task;
  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)
  75 {
  76         xprt_clear_binding(xprt);
  77         rpc_wake_up(&xprt->binding);
  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
  96         dprintk("RPC: %4d rpc_getport(%s, %u, %u, %d)\n",
  97                         task->tk_pid, clnt->cl_server,
  98                         clnt->cl_prog, clnt->cl_vers, xprt->prot);
  99
 100         /* Autobind on cloned rpc clients is discouraged */
 101         BUG_ON(clnt->cl_parent != clnt);
 102
 103         if (xprt_test_and_set_binding(xprt)) {
 104                 task->tk_status = -EACCES;      /* tell caller to check again */
 105                 rpc_sleep_on(&xprt->binding, task, NULL, NULL);
 106                 return;
 107         }
 108
 109         /* Someone else may have bound if we slept */
 110         if (xprt_bound(xprt)) {
 111                 task->tk_status = 0;
 112                 goto bailout_nofree;
 113         }
 114
 115         map = pmap_map_alloc();
 116         if (!map) {
 117                 task->tk_status = -ENOMEM;
 118                 goto bailout_nofree;
 119         }
 120         map->pm_prog = clnt->cl_prog;
 121         map->pm_vers = clnt->cl_vers;
 122         map->pm_prot = xprt->prot;
 123         map->pm_port = 0;
 124         map->pm_task = task;
 125
 126         rpc_peeraddr(clnt, (struct sockaddr *) &addr, sizeof(addr));
 127         pmap_clnt = pmap_create(clnt->cl_server, &addr, map->pm_prot, 0);
 128         if (IS_ERR(pmap_clnt)) {
 129                 task->tk_status = PTR_ERR(pmap_clnt);
 130                 goto bailout;
 131         }
 132
 133         child = rpc_run_task(pmap_clnt, RPC_TASK_ASYNC, &pmap_getport_ops, map);
 134         if (IS_ERR(child)) {
 135                 task->tk_status = -EIO;
 136                 goto bailout;
 137         }
 138         rpc_release_task(child);
 139
 140         rpc_sleep_on(&xprt->binding, task, NULL, NULL);
 141
 142         task->tk_xprt->stat.bind_count++;
 143         return;
 144
 145 bailout:
 146         pmap_map_free(map);
 147 bailout_nofree:
 148         pmap_wake_portmap_waiters(xprt);
 149 }
 150
 151 #ifdef CONFIG_ROOT_NFS
 152 /**
 153  * rpc_getport_external - obtain the port for a given RPC service on a given host
 154  * @sin: address of remote peer
 155  * @prog: RPC program number to bind
 156  * @vers: RPC version number to bind
 157  * @prot: transport protocol to use to make this request
 158  *
 159  * This one is called from outside the RPC client in a synchronous task context.
 160  */
 161 int rpc_getport_external(struct sockaddr_in *sin, __u32 prog, __u32 vers, int prot)
 162 {
 163         struct portmap_args map = {
 164                 .pm_prog        = prog,
 165                 .pm_vers        = vers,
 166                 .pm_prot        = prot,
 167                 .pm_port        = 0
 168         };
 169         struct rpc_message msg = {
 170                 .rpc_proc       = &pmap_procedures[PMAP_GETPORT],
 171                 .rpc_argp       = &map,
 172                 .rpc_resp       = &map.pm_port,
 173         };
 174         struct rpc_clnt *pmap_clnt;
 175         char            hostname[32];
 176         int             status;
 177
 178         dprintk("RPC:      rpc_getport_external(%u.%u.%u.%u, %u, %u, %d)\n",
 179                         NIPQUAD(sin->sin_addr.s_addr), prog, vers, prot);
 180
 181         sprintf(hostname, "%u.%u.%u.%u", NIPQUAD(sin->sin_addr.s_addr));
 182         pmap_clnt = pmap_create(hostname, sin, prot, 0);
 183         if (IS_ERR(pmap_clnt))
 184                 return PTR_ERR(pmap_clnt);
 185
 186         /* Setup the call info struct */
 187         status = rpc_call_sync(pmap_clnt, &msg, 0);
 188
 189         if (status >= 0) {
 190                 if (map.pm_port != 0)
 191                         return map.pm_port;
 192                 status = -EACCES;
 193         }
 194         return status;
 195 }
 196 #endif
 197
 198 /*
 199  * Portmapper child task invokes this callback via tk_exit.
 200  */
 201 static void pmap_getport_done(struct rpc_task *child, void *data)
 202 {
 203         struct portmap_args *map = data;
 204         struct rpc_task *task = map->pm_task;
 205         struct rpc_xprt *xprt = task->tk_xprt;
 206         int status = child->tk_status;
 207
 208         if (status < 0) {
 209                 /* Portmapper not available */
 210                 xprt->ops->set_port(xprt, 0);
 211                 task->tk_status = status;
 212         } else if (map->pm_port == 0) {
 213                 /* Requested RPC service wasn't registered */
 214                 xprt->ops->set_port(xprt, 0);
 215                 task->tk_status = -EACCES;
 216         } else {
 217                 /* Succeeded */
 218                 xprt->ops->set_port(xprt, map->pm_port);
 219                 xprt_set_bound(xprt);
 220                 task->tk_status = 0;
 221         }
 222
 223         dprintk("RPC: %4d pmap_getport_done(status %d, port %u)\n",
 224                         child->tk_pid, child->tk_status, map->pm_port);
 225
 226         pmap_wake_portmap_waiters(xprt);
 227 }
 228
 229 /**
 230  * rpc_register - set or unset a port registration with the local portmapper
 231  * @prog: RPC program number to bind
 232  * @vers: RPC version number to bind
 233  * @prot: transport protocol to use to make this request
 234  * @port: port value to register
 235  * @okay: result code
 236  *
 237  * port == 0 means unregister, port != 0 means register.
 238  */
 239 int rpc_register(u32 prog, u32 vers, int prot, unsigned short port, int *okay)
 240 {
 241         struct sockaddr_in      sin = {
 242                 .sin_family     = AF_INET,
 243                 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
 244         };
 245         struct portmap_args     map = {
 246                 .pm_prog        = prog,
 247                 .pm_vers        = vers,
 248                 .pm_prot        = prot,
 249                 .pm_port        = port,
 250         };
 251         struct rpc_message msg = {
 252                 .rpc_proc       = &pmap_procedures[port ? PMAP_SET : PMAP_UNSET],
 253                 .rpc_argp       = &map,
 254                 .rpc_resp       = okay,
 255         };
 256         struct rpc_clnt         *pmap_clnt;
 257         int error = 0;
 258
 259         dprintk("RPC: registering (%u, %u, %d, %u) with portmapper.\n",
 260                         prog, vers, prot, port);
 261
 262         pmap_clnt = pmap_create("localhost", &sin, IPPROTO_UDP, 1);
 263         if (IS_ERR(pmap_clnt)) {
 264                 error = PTR_ERR(pmap_clnt);
 265                 dprintk("RPC: couldn't create pmap client. Error = %d\n", error);
 266                 return error;
 267         }
 268
 269         error = rpc_call_sync(pmap_clnt, &msg, 0);
 270
 271         if (error < 0) {
 272                 printk(KERN_WARNING
 273                         "RPC: failed to contact portmap (errno %d).\n",
 274                         error);
 275         }
 276         dprintk("RPC: registration status %d/%d\n", error, *okay);
 277
 278         /* Client deleted automatically because cl_oneshot == 1 */
 279         return error;
 280 }
 281
 282 static struct rpc_clnt *pmap_create(char *hostname, struct sockaddr_in *srvaddr, int proto, int privileged)
 283 {
 284         struct rpc_create_args args = {
 285                 .protocol       = proto,
 286                 .address        = (struct sockaddr *)srvaddr,
 287                 .addrsize       = sizeof(*srvaddr),
 288                 .servername     = hostname,
 289                 .program        = &pmap_program,
 290                 .version        = RPC_PMAP_VERSION,
 291                 .authflavor     = RPC_AUTH_UNIX,
 292                 .flags          = (RPC_CLNT_CREATE_ONESHOT |
 293                                    RPC_CLNT_CREATE_NOPING),
 294         };
 295
 296         srvaddr->sin_port = htons(RPC_PMAP_PORT);
 297         if (!privileged)
 298                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 299         return rpc_create(&args);
 300 }
 301
 302 /*
 303  * XDR encode/decode functions for PMAP
 304  */
 305 static int xdr_encode_mapping(struct rpc_rqst *req, u32 *p, struct portmap_args *map)
 306 {
 307         dprintk("RPC: xdr_encode_mapping(%u, %u, %u, %u)\n",
 308                 map->pm_prog, map->pm_vers, map->pm_prot, map->pm_port);
 309         *p++ = htonl(map->pm_prog);
 310         *p++ = htonl(map->pm_vers);
 311         *p++ = htonl(map->pm_prot);
 312         *p++ = htonl(map->pm_port);
 313
 314         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 315         return 0;
 316 }
 317
 318 static int xdr_decode_port(struct rpc_rqst *req, u32 *p, unsigned short *portp)
 319 {
 320         *portp = (unsigned short) ntohl(*p++);
 321         return 0;
 322 }
 323
 324 static int xdr_decode_bool(struct rpc_rqst *req, u32 *p, unsigned int *boolp)
 325 {
 326         *boolp = (unsigned int) ntohl(*p++);
 327         return 0;
 328 }
 329
 330 static struct rpc_procinfo      pmap_procedures[] = {
 331 [PMAP_SET] = {
 332           .p_proc               = PMAP_SET,
 333           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 334           .p_decode             = (kxdrproc_t) xdr_decode_bool,
 335           .p_bufsiz             = 4,
 336           .p_count              = 1,
 337           .p_statidx            = PMAP_SET,
 338           .p_name               = "SET",
 339         },
 340 [PMAP_UNSET] = {
 341           .p_proc               = PMAP_UNSET,
 342           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 343           .p_decode             = (kxdrproc_t) xdr_decode_bool,
 344           .p_bufsiz             = 4,
 345           .p_count              = 1,
 346           .p_statidx            = PMAP_UNSET,
 347           .p_name               = "UNSET",
 348         },
 349 [PMAP_GETPORT] = {
 350           .p_proc               = PMAP_GETPORT,
 351           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 352           .p_decode             = (kxdrproc_t) xdr_decode_port,
 353           .p_bufsiz             = 4,
 354           .p_count              = 1,
 355           .p_statidx            = PMAP_GETPORT,
 356           .p_name               = "GETPORT",
 357         },
 358 };
 359
 360 static struct rpc_version       pmap_version2 = {
 361         .number         = 2,
 362         .nrprocs        = 4,
 363         .procs          = pmap_procedures
 364 };
 365
 366 static struct rpc_version *     pmap_version[] = {
 367         NULL,
 368         NULL,
 369         &pmap_version2
 370 };
 371
 372 static struct rpc_stat          pmap_stats;
 373
 374 static struct rpc_program       pmap_program = {
 375         .name           = "portmap",
 376         .number         = RPC_PMAP_PROGRAM,
 377         .nrvers         = ARRAY_SIZE(pmap_version),
 378         .version        = pmap_version,
 379         .stats          = &pmap_stats,
 380 };