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         struct portmap_args *map = data;
  66
  67         xprt_put(map->pm_xprt);
  68         pmap_map_free(map);
  69 }
  70
  71 static const struct rpc_call_ops pmap_getport_ops = {
  72         .rpc_call_prepare       = pmap_getport_prepare,
  73         .rpc_call_done          = pmap_getport_done,
  74         .rpc_release            = pmap_map_release,
  75 };
  76
  77 static inline void pmap_wake_portmap_waiters(struct rpc_xprt *xprt, int status)
  78 {
  79         xprt_clear_binding(xprt);
  80         rpc_wake_up_status(&xprt->binding, status);
  81 }
  82
  83 /**
  84  * rpc_getport - obtain the port for a given RPC service on a given host
  85  * @task: task that is waiting for portmapper request
  86  *
  87  * This one can be called for an ongoing RPC request, and can be used in
  88  * an async (rpciod) context.
  89  */
  90 void rpc_getport(struct rpc_task *task)
  91 {
  92         struct rpc_clnt *clnt = task->tk_client;
  93         struct rpc_xprt *xprt = task->tk_xprt;
  94         struct sockaddr_in addr;
  95         struct portmap_args *map;
  96         struct rpc_clnt *pmap_clnt;
  97         struct rpc_task *child;
  98         int status;
  99
 100         dprintk("RPC: %4d rpc_getport(%s, %u, %u, %d)\n",
 101                         task->tk_pid, clnt->cl_server,
 102                         clnt->cl_prog, clnt->cl_vers, xprt->prot);
 103
 104         /* Autobind on cloned rpc clients is discouraged */
 105         BUG_ON(clnt->cl_parent != clnt);
 106
 107         status = -EACCES;               /* tell caller to check again */
 108         if (xprt_test_and_set_binding(xprt))
 109                 goto bailout_nowake;
 110
 111         /* Put self on queue before sending rpcbind request, in case
 112          * pmap_getport_done completes before we return from rpc_run_task */
 113         rpc_sleep_on(&xprt->binding, task, NULL, NULL);
 114
 115         /* Someone else may have bound if we slept */
 116         status = 0;
 117         if (xprt_bound(xprt))
 118                 goto bailout_nofree;
 119
 120         status = -ENOMEM;
 121         map = pmap_map_alloc();
 122         if (!map)
 123                 goto bailout_nofree;
 124         map->pm_prog = clnt->cl_prog;
 125         map->pm_vers = clnt->cl_vers;
 126         map->pm_prot = xprt->prot;
 127         map->pm_port = 0;
 128         map->pm_xprt = xprt_get(xprt);
 129
 130         rpc_peeraddr(clnt, (struct sockaddr *) &addr, sizeof(addr));
 131         pmap_clnt = pmap_create(clnt->cl_server, &addr, map->pm_prot, 0);
 132         status = PTR_ERR(pmap_clnt);
 133         if (IS_ERR(pmap_clnt))
 134                 goto bailout;
 135
 136         status = -EIO;
 137         child = rpc_run_task(pmap_clnt, RPC_TASK_ASYNC, &pmap_getport_ops, map);
 138         if (IS_ERR(child))
 139                 goto bailout_nofree;
 140         rpc_put_task(child);
 141
 142         task->tk_xprt->stat.bind_count++;
 143         return;
 144
 145 bailout:
 146         pmap_map_free(map);
 147         xprt_put(xprt);
 148 bailout_nofree:
 149         pmap_wake_portmap_waiters(xprt, status);
 150 bailout_nowake:
 151         task->tk_status = status;
 152 }
 153
 154 #ifdef CONFIG_ROOT_NFS
 155 /**
 156  * rpc_getport_external - obtain the port for a given RPC service on a given host
 157  * @sin: address of remote peer
 158  * @prog: RPC program number to bind
 159  * @vers: RPC version number to bind
 160  * @prot: transport protocol to use to make this request
 161  *
 162  * This one is called from outside the RPC client in a synchronous task context.
 163  */
 164 int rpc_getport_external(struct sockaddr_in *sin, __u32 prog, __u32 vers, int prot)
 165 {
 166         struct portmap_args map = {
 167                 .pm_prog        = prog,
 168                 .pm_vers        = vers,
 169                 .pm_prot        = prot,
 170                 .pm_port        = 0
 171         };
 172         struct rpc_message msg = {
 173                 .rpc_proc       = &pmap_procedures[PMAP_GETPORT],
 174                 .rpc_argp       = &map,
 175                 .rpc_resp       = &map.pm_port,
 176         };
 177         struct rpc_clnt *pmap_clnt;
 178         char            hostname[32];
 179         int             status;
 180
 181         dprintk("RPC:      rpc_getport_external(%u.%u.%u.%u, %u, %u, %d)\n",
 182                         NIPQUAD(sin->sin_addr.s_addr), prog, vers, prot);
 183
 184         sprintf(hostname, "%u.%u.%u.%u", NIPQUAD(sin->sin_addr.s_addr));
 185         pmap_clnt = pmap_create(hostname, sin, prot, 0);
 186         if (IS_ERR(pmap_clnt))
 187                 return PTR_ERR(pmap_clnt);
 188
 189         /* Setup the call info struct */
 190         status = rpc_call_sync(pmap_clnt, &msg, 0);
 191
 192         if (status >= 0) {
 193                 if (map.pm_port != 0)
 194                         return map.pm_port;
 195                 status = -EACCES;
 196         }
 197         return status;
 198 }
 199 #endif
 200
 201 /*
 202  * Portmapper child task invokes this callback via tk_exit.
 203  */
 204 static void pmap_getport_done(struct rpc_task *child, void *data)
 205 {
 206         struct portmap_args *map = data;
 207         struct rpc_xprt *xprt = map->pm_xprt;
 208         int status = child->tk_status;
 209
 210         if (status < 0) {
 211                 /* Portmapper not available */
 212                 xprt->ops->set_port(xprt, 0);
 213         } else if (map->pm_port == 0) {
 214                 /* Requested RPC service wasn't registered */
 215                 xprt->ops->set_port(xprt, 0);
 216                 status = -EACCES;
 217         } else {
 218                 /* Succeeded */
 219                 xprt->ops->set_port(xprt, map->pm_port);
 220                 xprt_set_bound(xprt);
 221                 status = 0;
 222         }
 223
 224         dprintk("RPC: %4d pmap_getport_done(status %d, port %u)\n",
 225                         child->tk_pid, status, map->pm_port);
 226
 227         pmap_wake_portmap_waiters(xprt, status);
 228 }
 229
 230 /**
 231  * rpc_register - set or unset a port registration with the local portmapper
 232  * @prog: RPC program number to bind
 233  * @vers: RPC version number to bind
 234  * @prot: transport protocol to use to make this request
 235  * @port: port value to register
 236  * @okay: result code
 237  *
 238  * port == 0 means unregister, port != 0 means register.
 239  */
 240 int rpc_register(u32 prog, u32 vers, int prot, unsigned short port, int *okay)
 241 {
 242         struct sockaddr_in      sin = {
 243                 .sin_family     = AF_INET,
 244                 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
 245         };
 246         struct portmap_args     map = {
 247                 .pm_prog        = prog,
 248                 .pm_vers        = vers,
 249                 .pm_prot        = prot,
 250                 .pm_port        = port,
 251         };
 252         struct rpc_message msg = {
 253                 .rpc_proc       = &pmap_procedures[port ? PMAP_SET : PMAP_UNSET],
 254                 .rpc_argp       = &map,
 255                 .rpc_resp       = okay,
 256         };
 257         struct rpc_clnt         *pmap_clnt;
 258         int error = 0;
 259
 260         dprintk("RPC: registering (%u, %u, %d, %u) with portmapper.\n",
 261                         prog, vers, prot, port);
 262
 263         pmap_clnt = pmap_create("localhost", &sin, IPPROTO_UDP, 1);
 264         if (IS_ERR(pmap_clnt)) {
 265                 error = PTR_ERR(pmap_clnt);
 266                 dprintk("RPC: couldn't create pmap client. Error = %d\n", error);
 267                 return error;
 268         }
 269
 270         error = rpc_call_sync(pmap_clnt, &msg, 0);
 271
 272         if (error < 0) {
 273                 printk(KERN_WARNING
 274                         "RPC: failed to contact portmap (errno %d).\n",
 275                         error);
 276         }
 277         dprintk("RPC: registration status %d/%d\n", error, *okay);
 278
 279         /* Client deleted automatically because cl_oneshot == 1 */
 280         return error;
 281 }
 282
 283 static struct rpc_clnt *pmap_create(char *hostname, struct sockaddr_in *srvaddr, int proto, int privileged)
 284 {
 285         struct rpc_create_args args = {
 286                 .protocol       = proto,
 287                 .address        = (struct sockaddr *)srvaddr,
 288                 .addrsize       = sizeof(*srvaddr),
 289                 .servername     = hostname,
 290                 .program        = &pmap_program,
 291                 .version        = RPC_PMAP_VERSION,
 292                 .authflavor     = RPC_AUTH_UNIX,
 293                 .flags          = (RPC_CLNT_CREATE_ONESHOT |
 294                                    RPC_CLNT_CREATE_NOPING),
 295         };
 296
 297         srvaddr->sin_port = htons(RPC_PMAP_PORT);
 298         if (!privileged)
 299                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 300         return rpc_create(&args);
 301 }
 302
 303 /*
 304  * XDR encode/decode functions for PMAP
 305  */
 306 static int xdr_encode_mapping(struct rpc_rqst *req, __be32 *p, struct portmap_args *map)
 307 {
 308         dprintk("RPC: xdr_encode_mapping(%u, %u, %u, %u)\n",
 309                 map->pm_prog, map->pm_vers, map->pm_prot, map->pm_port);
 310         *p++ = htonl(map->pm_prog);
 311         *p++ = htonl(map->pm_vers);
 312         *p++ = htonl(map->pm_prot);
 313         *p++ = htonl(map->pm_port);
 314
 315         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
 316         return 0;
 317 }
 318
 319 static int xdr_decode_port(struct rpc_rqst *req, __be32 *p, unsigned short *portp)
 320 {
 321         *portp = (unsigned short) ntohl(*p++);
 322         return 0;
 323 }
 324
 325 static int xdr_decode_bool(struct rpc_rqst *req, __be32 *p, unsigned int *boolp)
 326 {
 327         *boolp = (unsigned int) ntohl(*p++);
 328         return 0;
 329 }
 330
 331 static struct rpc_procinfo      pmap_procedures[] = {
 332 [PMAP_SET] = {
 333           .p_proc               = PMAP_SET,
 334           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 335           .p_decode             = (kxdrproc_t) xdr_decode_bool,
 336           .p_bufsiz             = 4,
 337           .p_count              = 1,
 338           .p_statidx            = PMAP_SET,
 339           .p_name               = "SET",
 340         },
 341 [PMAP_UNSET] = {
 342           .p_proc               = PMAP_UNSET,
 343           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 344           .p_decode             = (kxdrproc_t) xdr_decode_bool,
 345           .p_bufsiz             = 4,
 346           .p_count              = 1,
 347           .p_statidx            = PMAP_UNSET,
 348           .p_name               = "UNSET",
 349         },
 350 [PMAP_GETPORT] = {
 351           .p_proc               = PMAP_GETPORT,
 352           .p_encode             = (kxdrproc_t) xdr_encode_mapping,
 353           .p_decode             = (kxdrproc_t) xdr_decode_port,
 354           .p_bufsiz             = 4,
 355           .p_count              = 1,
 356           .p_statidx            = PMAP_GETPORT,
 357           .p_name               = "GETPORT",
 358         },
 359 };
 360
 361 static struct rpc_version       pmap_version2 = {
 362         .number         = 2,
 363         .nrprocs        = 4,
 364         .procs          = pmap_procedures
 365 };
 366
 367 static struct rpc_version *     pmap_version[] = {
 368         NULL,
 369         NULL,
 370         &pmap_version2
 371 };
 372
 373 static struct rpc_stat          pmap_stats;
 374
 375 static struct rpc_program       pmap_program = {
 376         .name           = "portmap",
 377         .number         = RPC_PMAP_PROGRAM,
 378         .nrvers         = ARRAY_SIZE(pmap_version),
 379         .version        = pmap_version,
 380         .stats          = &pmap_stats,
 381 };