fs/lockd/mon.c

   1 /*
   2  * linux/fs/lockd/mon.c
   3  *
   4  * The kernel statd client.
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/utsname.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sunrpc/clnt.h>
  13 #include <linux/sunrpc/xprtsock.h>
  14 #include <linux/sunrpc/svc.h>
  15 #include <linux/lockd/lockd.h>
  16 #include <linux/lockd/sm_inter.h>
  17
  18
  19 #define NLMDBG_FACILITY         NLMDBG_MONITOR
  20
  21 #define XDR_ADDRBUF_LEN         (20)
  22
  23 static struct rpc_clnt *        nsm_create(void);
  24
  25 static struct rpc_program       nsm_program;
  26
  27 /*
  28  * Local NSM state
  29  */
  30 int                             nsm_local_state;
  31
  32 /*
  33  * Common procedure for SM_MON/SM_UNMON calls
  34  */
  35 static int
  36 nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
  37 {
  38         struct rpc_clnt *clnt;
  39         int             status;
  40         struct nsm_args args;
  41         struct rpc_message msg = {
  42                 .rpc_argp       = &args,
  43                 .rpc_resp       = res,
  44         };
  45
  46         clnt = nsm_create();
  47         if (IS_ERR(clnt)) {
  48                 status = PTR_ERR(clnt);
  49                 goto out;
  50         }
  51
  52         memset(&args, 0, sizeof(args));
  53         args.mon_name = nsm->sm_name;
  54         args.addr = nsm_addr_in(nsm)->sin_addr.s_addr;
  55         args.prog = NLM_PROGRAM;
  56         args.vers = 3;
  57         args.proc = NLMPROC_NSM_NOTIFY;
  58         memset(res, 0, sizeof(*res));
  59
  60         msg.rpc_proc = &clnt->cl_procinfo[proc];
  61         status = rpc_call_sync(clnt, &msg, 0);
  62         if (status < 0)
  63                 printk(KERN_DEBUG "nsm_mon_unmon: rpc failed, status=%d\n",
  64                         status);
  65         else
  66                 status = 0;
  67         rpc_shutdown_client(clnt);
  68  out:
  69         return status;
  70 }
  71
  72 /*
  73  * Set up monitoring of a remote host
  74  */
  75 int
  76 nsm_monitor(struct nlm_host *host)
  77 {
  78         struct nsm_handle *nsm = host->h_nsmhandle;
  79         struct nsm_res  res;
  80         int             status;
  81
  82         dprintk("lockd: nsm_monitor(%s)\n", host->h_name);
  83         BUG_ON(nsm == NULL);
  84
  85         if (nsm->sm_monitored)
  86                 return 0;
  87
  88         status = nsm_mon_unmon(nsm, SM_MON, &res);
  89
  90         if (status < 0 || res.status != 0)
  91                 printk(KERN_NOTICE "lockd: cannot monitor %s\n", host->h_name);
  92         else
  93                 nsm->sm_monitored = 1;
  94         return status;
  95 }
  96
  97 /*
  98  * Cease to monitor remote host
  99  */
 100 int
 101 nsm_unmonitor(struct nlm_host *host)
 102 {
 103         struct nsm_handle *nsm = host->h_nsmhandle;
 104         struct nsm_res  res;
 105         int             status = 0;
 106
 107         if (nsm == NULL)
 108                 return 0;
 109         host->h_nsmhandle = NULL;
 110
 111         if (atomic_read(&nsm->sm_count) == 1
 112          && nsm->sm_monitored && !nsm->sm_sticky) {
 113                 dprintk("lockd: nsm_unmonitor(%s)\n", host->h_name);
 114
 115                 status = nsm_mon_unmon(nsm, SM_UNMON, &res);
 116                 if (status < 0)
 117                         printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
 118                                         host->h_name);
 119                 else
 120                         nsm->sm_monitored = 0;
 121         }
 122         nsm_release(nsm);
 123         return status;
 124 }
 125
 126 /*
 127  * Create NSM client for the local host
 128  */
 129 static struct rpc_clnt *
 130 nsm_create(void)
 131 {
 132         struct sockaddr_in      sin = {
 133                 .sin_family     = AF_INET,
 134                 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
 135                 .sin_port       = 0,
 136         };
 137         struct rpc_create_args args = {
 138                 .protocol       = XPRT_TRANSPORT_UDP,
 139                 .address        = (struct sockaddr *)&sin,
 140                 .addrsize       = sizeof(sin),
 141                 .servername     = "localhost",
 142                 .program        = &nsm_program,
 143                 .version        = SM_VERSION,
 144                 .authflavor     = RPC_AUTH_NULL,
 145         };
 146
 147         return rpc_create(&args);
 148 }
 149
 150 /*
 151  * XDR functions for NSM.
 152  *
 153  * See http://www.opengroup.org/ for details on the Network
 154  * Status Monitor wire protocol.
 155  */
 156
 157 static __be32 *xdr_encode_nsm_string(__be32 *p, char *string)
 158 {
 159         size_t len = strlen(string);
 160
 161         if (len > SM_MAXSTRLEN)
 162                 len = SM_MAXSTRLEN;
 163         return xdr_encode_opaque(p, string, len);
 164 }
 165
 166 /*
 167  * "mon_name" specifies the host to be monitored.
 168  *
 169  * Linux uses a text version of the IP address of the remote
 170  * host as the host identifier (the "mon_name" argument).
 171  *
 172  * Linux statd always looks up the canonical hostname first for
 173  * whatever remote hostname it receives, so this works alright.
 174  */
 175 static __be32 *xdr_encode_mon_name(__be32 *p, struct nsm_args *argp)
 176 {
 177         char    buffer[XDR_ADDRBUF_LEN + 1];
 178         char    *name = argp->mon_name;
 179
 180         if (!nsm_use_hostnames) {
 181                 snprintf(buffer, XDR_ADDRBUF_LEN,
 182                          NIPQUAD_FMT, NIPQUAD(argp->addr));
 183                 name = buffer;
 184         }
 185
 186         return xdr_encode_nsm_string(p, name);
 187 }
 188
 189 /*
 190  * The "my_id" argument specifies the hostname and RPC procedure
 191  * to be called when the status manager receives notification
 192  * (via the SM_NOTIFY call) that the state of host "mon_name"
 193  * has changed.
 194  */
 195 static __be32 *xdr_encode_my_id(__be32 *p, struct nsm_args *argp)
 196 {
 197         p = xdr_encode_nsm_string(p, utsname()->nodename);
 198         if (!p)
 199                 return ERR_PTR(-EIO);
 200
 201         *p++ = htonl(argp->prog);
 202         *p++ = htonl(argp->vers);
 203         *p++ = htonl(argp->proc);
 204
 205         return p;
 206 }
 207
 208 /*
 209  * The "mon_id" argument specifies the non-private arguments
 210  * of an SM_MON or SM_UNMON call.
 211  */
 212 static __be32 *xdr_encode_mon_id(__be32 *p, struct nsm_args *argp)
 213 {
 214         p = xdr_encode_mon_name(p, argp);
 215         if (!p)
 216                 return ERR_PTR(-EIO);
 217
 218         return xdr_encode_my_id(p, argp);
 219 }
 220
 221 /*
 222  * The "priv" argument may contain private information required
 223  * by the SM_MON call. This information will be supplied in the
 224  * SM_NOTIFY call.
 225  *
 226  * Linux provides the raw IP address of the monitored host,
 227  * left in network byte order.
 228  */
 229 static __be32 *xdr_encode_priv(__be32 *p, struct nsm_args *argp)
 230 {
 231         *p++ = argp->addr;
 232         *p++ = 0;
 233         *p++ = 0;
 234         *p++ = 0;
 235
 236         return p;
 237 }
 238
 239 static int
 240 xdr_encode_mon(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
 241 {
 242         p = xdr_encode_mon_id(p, argp);
 243         if (IS_ERR(p))
 244                 return PTR_ERR(p);
 245
 246         p = xdr_encode_priv(p, argp);
 247         if (IS_ERR(p))
 248                 return PTR_ERR(p);
 249
 250         rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
 251         return 0;
 252 }
 253
 254 static int
 255 xdr_encode_unmon(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
 256 {
 257         p = xdr_encode_mon_id(p, argp);
 258         if (IS_ERR(p))
 259                 return PTR_ERR(p);
 260         rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
 261         return 0;
 262 }
 263
 264 static int
 265 xdr_decode_stat_res(struct rpc_rqst *rqstp, __be32 *p, struct nsm_res *resp)
 266 {
 267         resp->status = ntohl(*p++);
 268         resp->state = ntohl(*p++);
 269         dprintk("nsm: xdr_decode_stat_res status %d state %d\n",
 270                         resp->status, resp->state);
 271         return 0;
 272 }
 273
 274 static int
 275 xdr_decode_stat(struct rpc_rqst *rqstp, __be32 *p, struct nsm_res *resp)
 276 {
 277         resp->state = ntohl(*p++);
 278         return 0;
 279 }
 280
 281 #define SM_my_name_sz   (1+XDR_QUADLEN(SM_MAXSTRLEN))
 282 #define SM_my_id_sz     (SM_my_name_sz+3)
 283 #define SM_mon_name_sz  (1+XDR_QUADLEN(SM_MAXSTRLEN))
 284 #define SM_mon_id_sz    (SM_mon_name_sz+SM_my_id_sz)
 285 #define SM_priv_sz      (XDR_QUADLEN(SM_PRIV_SIZE))
 286 #define SM_mon_sz       (SM_mon_id_sz+SM_priv_sz)
 287 #define SM_monres_sz    2
 288 #define SM_unmonres_sz  1
 289
 290 static struct rpc_procinfo      nsm_procedures[] = {
 291 [SM_MON] = {
 292                 .p_proc         = SM_MON,
 293                 .p_encode       = (kxdrproc_t) xdr_encode_mon,
 294                 .p_decode       = (kxdrproc_t) xdr_decode_stat_res,
 295                 .p_arglen       = SM_mon_sz,
 296                 .p_replen       = SM_monres_sz,
 297                 .p_statidx      = SM_MON,
 298                 .p_name         = "MONITOR",
 299         },
 300 [SM_UNMON] = {
 301                 .p_proc         = SM_UNMON,
 302                 .p_encode       = (kxdrproc_t) xdr_encode_unmon,
 303                 .p_decode       = (kxdrproc_t) xdr_decode_stat,
 304                 .p_arglen       = SM_mon_id_sz,
 305                 .p_replen       = SM_unmonres_sz,
 306                 .p_statidx      = SM_UNMON,
 307                 .p_name         = "UNMONITOR",
 308         },
 309 };
 310
 311 static struct rpc_version       nsm_version1 = {
 312                 .number         = 1,
 313                 .nrprocs        = ARRAY_SIZE(nsm_procedures),
 314                 .procs          = nsm_procedures
 315 };
 316
 317 static struct rpc_version *     nsm_version[] = {
 318         [1] = &nsm_version1,
 319 };
 320
 321 static struct rpc_stat          nsm_stats;
 322
 323 static struct rpc_program       nsm_program = {
 324                 .name           = "statd",
 325                 .number         = SM_PROGRAM,
 326                 .nrvers         = ARRAY_SIZE(nsm_version),
 327                 .version        = nsm_version,
 328                 .stats          = &nsm_stats
 329 };