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/svc.h>
  14 #include <linux/lockd/lockd.h>
  15 #include <linux/lockd/sm_inter.h>
  16
  17
  18 #define NLMDBG_FACILITY         NLMDBG_MONITOR
  19
  20 static struct rpc_clnt *        nsm_create(void);
  21
  22 static struct rpc_program       nsm_program;
  23
  24 /*
  25  * Local NSM state
  26  */
  27 u32                             nsm_local_state;
  28
  29 /*
  30  * Common procedure for SM_MON/SM_UNMON calls
  31  */
  32 static int
  33 nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
  34 {
  35         struct rpc_clnt *clnt;
  36         int             status;
  37         struct nsm_args args;
  38         struct rpc_message msg = {
  39                 .rpc_argp       = &args,
  40                 .rpc_resp       = res,
  41         };
  42
  43         clnt = nsm_create();
  44         if (IS_ERR(clnt)) {
  45                 status = PTR_ERR(clnt);
  46                 goto out;
  47         }
  48
  49         memset(&args, 0, sizeof(args));
  50         args.addr = nsm->sm_addr.sin_addr.s_addr;
  51         args.prog = NLM_PROGRAM;
  52         args.vers = 3;
  53         args.proc = NLMPROC_NSM_NOTIFY;
  54         memset(res, 0, sizeof(*res));
  55
  56         msg.rpc_proc = &clnt->cl_procinfo[proc];
  57         status = rpc_call_sync(clnt, &msg, 0);
  58         if (status < 0)
  59                 printk(KERN_DEBUG "nsm_mon_unmon: rpc failed, status=%d\n",
  60                         status);
  61         else
  62                 status = 0;
  63  out:
  64         return status;
  65 }
  66
  67 /*
  68  * Set up monitoring of a remote host
  69  */
  70 int
  71 nsm_monitor(struct nlm_host *host)
  72 {
  73         struct nsm_handle *nsm = host->h_nsmhandle;
  74         struct nsm_res  res;
  75         int             status;
  76
  77         dprintk("lockd: nsm_monitor(%s)\n", host->h_name);
  78         BUG_ON(nsm == NULL);
  79
  80         if (nsm->sm_monitored)
  81                 return 0;
  82
  83         status = nsm_mon_unmon(nsm, SM_MON, &res);
  84
  85         if (status < 0 || res.status != 0)
  86                 printk(KERN_NOTICE "lockd: cannot monitor %s\n", host->h_name);
  87         else
  88                 nsm->sm_monitored = 1;
  89         return status;
  90 }
  91
  92 /*
  93  * Cease to monitor remote host
  94  */
  95 int
  96 nsm_unmonitor(struct nlm_host *host)
  97 {
  98         struct nsm_handle *nsm = host->h_nsmhandle;
  99         struct nsm_res  res;
 100         int             status = 0;
 101
 102         if (nsm == NULL)
 103                 return 0;
 104         host->h_nsmhandle = NULL;
 105
 106         if (atomic_read(&nsm->sm_count) == 1
 107          && nsm->sm_monitored && !nsm->sm_sticky) {
 108                 dprintk("lockd: nsm_unmonitor(%s)\n", host->h_name);
 109
 110                 status = nsm_mon_unmon(nsm, SM_UNMON, &res);
 111                 if (status < 0)
 112                         printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
 113                                         host->h_name);
 114                 else
 115                         nsm->sm_monitored = 0;
 116         }
 117         nsm_release(nsm);
 118         return status;
 119 }
 120
 121 /*
 122  * Create NSM client for the local host
 123  */
 124 static struct rpc_clnt *
 125 nsm_create(void)
 126 {
 127         struct sockaddr_in      sin = {
 128                 .sin_family     = AF_INET,
 129                 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
 130                 .sin_port       = 0,
 131         };
 132         struct rpc_create_args args = {
 133                 .protocol       = IPPROTO_UDP,
 134                 .address        = (struct sockaddr *)&sin,
 135                 .addrsize       = sizeof(sin),
 136                 .servername     = "localhost",
 137                 .program        = &nsm_program,
 138                 .version        = SM_VERSION,
 139                 .authflavor     = RPC_AUTH_NULL,
 140                 .flags          = (RPC_CLNT_CREATE_ONESHOT),
 141         };
 142
 143         return rpc_create(&args);
 144 }
 145
 146 /*
 147  * XDR functions for NSM.
 148  */
 149
 150 static u32 *
 151 xdr_encode_common(struct rpc_rqst *rqstp, u32 *p, struct nsm_args *argp)
 152 {
 153         char    buffer[20];
 154
 155         /*
 156          * Use the dotted-quad IP address of the remote host as
 157          * identifier. Linux statd always looks up the canonical
 158          * hostname first for whatever remote hostname it receives,
 159          * so this works alright.
 160          */
 161         sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(argp->addr));
 162         if (!(p = xdr_encode_string(p, buffer))
 163          || !(p = xdr_encode_string(p, utsname()->nodename)))
 164                 return ERR_PTR(-EIO);
 165         *p++ = htonl(argp->prog);
 166         *p++ = htonl(argp->vers);
 167         *p++ = htonl(argp->proc);
 168
 169         return p;
 170 }
 171
 172 static int
 173 xdr_encode_mon(struct rpc_rqst *rqstp, u32 *p, struct nsm_args *argp)
 174 {
 175         p = xdr_encode_common(rqstp, p, argp);
 176         if (IS_ERR(p))
 177                 return PTR_ERR(p);
 178
 179         /* Surprise - there may even be room for an IPv6 address now */
 180         *p++ = argp->addr;
 181         *p++ = 0;
 182         *p++ = 0;
 183         *p++ = 0;
 184         rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
 185         return 0;
 186 }
 187
 188 static int
 189 xdr_encode_unmon(struct rpc_rqst *rqstp, u32 *p, struct nsm_args *argp)
 190 {
 191         p = xdr_encode_common(rqstp, p, argp);
 192         if (IS_ERR(p))
 193                 return PTR_ERR(p);
 194         rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
 195         return 0;
 196 }
 197
 198 static int
 199 xdr_decode_stat_res(struct rpc_rqst *rqstp, u32 *p, struct nsm_res *resp)
 200 {
 201         resp->status = ntohl(*p++);
 202         resp->state = ntohl(*p++);
 203         dprintk("nsm: xdr_decode_stat_res status %d state %d\n",
 204                         resp->status, resp->state);
 205         return 0;
 206 }
 207
 208 static int
 209 xdr_decode_stat(struct rpc_rqst *rqstp, u32 *p, struct nsm_res *resp)
 210 {
 211         resp->state = ntohl(*p++);
 212         return 0;
 213 }
 214
 215 #define SM_my_name_sz   (1+XDR_QUADLEN(SM_MAXSTRLEN))
 216 #define SM_my_id_sz     (3+1+SM_my_name_sz)
 217 #define SM_mon_id_sz    (1+XDR_QUADLEN(20)+SM_my_id_sz)
 218 #define SM_mon_sz       (SM_mon_id_sz+4)
 219 #define SM_monres_sz    2
 220 #define SM_unmonres_sz  1
 221
 222 #ifndef MAX
 223 # define MAX(a, b)      (((a) > (b))? (a) : (b))
 224 #endif
 225
 226 static struct rpc_procinfo      nsm_procedures[] = {
 227 [SM_MON] = {
 228                 .p_proc         = SM_MON,
 229                 .p_encode       = (kxdrproc_t) xdr_encode_mon,
 230                 .p_decode       = (kxdrproc_t) xdr_decode_stat_res,
 231                 .p_bufsiz       = MAX(SM_mon_sz, SM_monres_sz) << 2,
 232                 .p_statidx      = SM_MON,
 233                 .p_name         = "MONITOR",
 234         },
 235 [SM_UNMON] = {
 236                 .p_proc         = SM_UNMON,
 237                 .p_encode       = (kxdrproc_t) xdr_encode_unmon,
 238                 .p_decode       = (kxdrproc_t) xdr_decode_stat,
 239                 .p_bufsiz       = MAX(SM_mon_id_sz, SM_unmonres_sz) << 2,
 240                 .p_statidx      = SM_UNMON,
 241                 .p_name         = "UNMONITOR",
 242         },
 243 };
 244
 245 static struct rpc_version       nsm_version1 = {
 246                 .number         = 1,
 247                 .nrprocs        = ARRAY_SIZE(nsm_procedures),
 248                 .procs          = nsm_procedures
 249 };
 250
 251 static struct rpc_version *     nsm_version[] = {
 252         [1] = &nsm_version1,
 253 };
 254
 255 static struct rpc_stat          nsm_stats;
 256
 257 static struct rpc_program       nsm_program = {
 258                 .name           = "statd",
 259                 .number         = SM_PROGRAM,
 260                 .nrvers         = ARRAY_SIZE(nsm_version),
 261                 .version        = nsm_version,
 262                 .stats          = &nsm_stats
 263 };