ext/raindrops/linux_inet_diag.c

   1 #include <ruby.h>
   2 #ifdef HAVE_RUBY_ST_H
   3 #  include <ruby/st.h>
   4 #else
   5 #  include <st.h>
   6 #endif
   7 #include "my_fileno.h"
   8 #ifdef __linux__
   9
  10 /* Ruby 1.8.6+ macros (for compatibility with Ruby 1.9) */
  11 #ifndef RSTRING_LEN
  12 #  define RSTRING_LEN(s) (RSTRING(s)->len)
  13 #endif
  14
  15 /* partial emulation of the 1.9 rb_thread_blocking_region under 1.8 */
  16 #ifndef HAVE_RB_THREAD_BLOCKING_REGION
  17 #  include <rubysig.h>
  18 #  define RUBY_UBF_IO ((rb_unblock_function_t *)-1)
  19 typedef void rb_unblock_function_t(void *);
  20 typedef VALUE rb_blocking_function_t(void *);
  21 static VALUE
  22 rb_thread_blocking_region(
  23         rb_blocking_function_t *func, void *data1,
  24         rb_unblock_function_t *ubf, void *data2)
  25 {
  26         VALUE rv;
  27
  28         TRAP_BEG;
  29         rv = func(data1);
  30         TRAP_END;
  31
  32         return rv;
  33 }
  34 #endif /* ! HAVE_RB_THREAD_BLOCKING_REGION */
  35
  36 #ifdef HAVE_RB_THREAD_IO_BLOCKING_REGION
  37 VALUE rb_thread_io_blocking_region(rb_blocking_function_t *, void *, int);
  38 #else
  39 #  define rb_thread_io_blocking_region(fn,data,fd) \
  40       rb_thread_blocking_region((fn),(data),RUBY_UBF_IO,0)
  41 #endif /* HAVE_RB_THREAD_IO_BLOCKING_REGION */
  42
  43 #include <assert.h>
  44 #include <errno.h>
  45 #include <sys/socket.h>
  46 #include <sys/types.h>
  47 #include <netdb.h>
  48 #include <unistd.h>
  49 #include <fcntl.h>
  50 #include <string.h>
  51 #include <asm/types.h>
  52 #include <netinet/in.h>
  53 #include <arpa/inet.h>
  54 #include <netinet/tcp.h>
  55 #include <linux/netlink.h>
  56 #include <linux/rtnetlink.h>
  57 #include <linux/inet_diag.h>
  58
  59 union any_addr {
  60         struct sockaddr_storage ss;
  61         struct sockaddr sa;
  62         struct sockaddr_in in;
  63         struct sockaddr_in6 in6;
  64 };
  65
  66 static size_t page_size;
  67 static unsigned g_seq;
  68 static VALUE cListenStats, cIDSock;
  69 static ID id_new;
  70
  71 struct listen_stats {
  72         uint32_t active;
  73         uint32_t listener_p:1;
  74         uint32_t queued:31;
  75 };
  76
  77 #define OPLEN (sizeof(struct inet_diag_bc_op) + \
  78                sizeof(struct inet_diag_hostcond) + \
  79                sizeof(struct sockaddr_storage))
  80
  81 struct nogvl_args {
  82         st_table *table;
  83         struct iovec iov[3]; /* last iov holds inet_diag bytecode */
  84         struct listen_stats stats;
  85         int fd;
  86 };
  87
  88 #ifdef SOCK_CLOEXEC
  89 #  define my_SOCK_RAW (SOCK_RAW|SOCK_CLOEXEC)
  90 #  define FORCE_CLOEXEC(v) (v)
  91 #else
  92 #  define my_SOCK_RAW SOCK_RAW
  93 static VALUE FORCE_CLOEXEC(VALUE io)
  94 {
  95         int fd = my_fileno(io);
  96         int flags = fcntl(fd, F_SETFD, FD_CLOEXEC);
  97         if (flags == -1)
  98                 rb_sys_fail("fcntl(F_SETFD, FD_CLOEXEC)");
  99         return io;
 100 }
 101 #endif
 102
 103 /*
 104  * call-seq:
 105  *      Raindrops::InetDiagSocket.new   -> Socket
 106  *
 107  * Creates a new Socket object for the netlink inet_diag facility
 108  */
 109 static VALUE ids_s_new(VALUE klass)
 110 {
 111         VALUE argv[3];
 112
 113         argv[0] = INT2NUM(AF_NETLINK);
 114         argv[1] = INT2NUM(my_SOCK_RAW);
 115         argv[2] = INT2NUM(NETLINK_INET_DIAG);
 116
 117         return FORCE_CLOEXEC(rb_call_super(3, argv));
 118 }
 119
 120 /* creates a Ruby ListenStats Struct based on our internal listen_stats */
 121 static VALUE rb_listen_stats(struct listen_stats *stats)
 122 {
 123         VALUE active = UINT2NUM(stats->active);
 124         VALUE queued = UINT2NUM(stats->queued);
 125
 126         return rb_struct_new(cListenStats, active, queued);
 127 }
 128
 129 static int st_free_data(st_data_t key, st_data_t value, st_data_t ignored)
 130 {
 131         xfree((void *)key);
 132         xfree((void *)value);
 133
 134         return ST_DELETE;
 135 }
 136
 137 static int st_to_hash(st_data_t key, st_data_t value, VALUE hash)
 138 {
 139         struct listen_stats *stats = (struct listen_stats *)value;
 140
 141         if (stats->listener_p) {
 142                 VALUE k = rb_str_new2((const char *)key);
 143                 VALUE v = rb_listen_stats(stats);
 144
 145                 OBJ_FREEZE(k);
 146                 rb_hash_aset(hash, k, v);
 147         }
 148         return st_free_data(key, value, 0);
 149 }
 150
 151 static int st_AND_hash(st_data_t key, st_data_t value, VALUE hash)
 152 {
 153         struct listen_stats *stats = (struct listen_stats *)value;
 154
 155         if (stats->listener_p) {
 156                 VALUE k = rb_str_new2((const char *)key);
 157
 158                 if (rb_hash_lookup(hash, k) == Qtrue) {
 159                         VALUE v = rb_listen_stats(stats);
 160                         OBJ_FREEZE(k);
 161                         rb_hash_aset(hash, k, v);
 162                 }
 163         }
 164         return st_free_data(key, value, 0);
 165 }
 166
 167 static const char *addr_any(sa_family_t family)
 168 {
 169         static const char ipv4[] = "0.0.0.0";
 170         static const char ipv6[] = "[::]";
 171
 172         if (family == AF_INET)
 173                 return ipv4;
 174         assert(family == AF_INET6 && "unknown family");
 175         return ipv6;
 176 }
 177
 178 static void bug_warn(void)
 179 {
 180         fprintf(stderr, "Please report how you produced this at "\
 181                         "raindrops@librelist.org\n");
 182         fflush(stderr);
 183 }
 184
 185 static struct listen_stats *stats_for(st_table *table, struct inet_diag_msg *r)
 186 {
 187         char *key, *port, *old_key;
 188         size_t alloca_len;
 189         struct listen_stats *stats;
 190         size_t keylen;
 191         size_t portlen = sizeof("65535");
 192         union any_addr sa;
 193         socklen_t len = sizeof(struct sockaddr_storage);
 194         int rc;
 195         int flags = NI_NUMERICHOST | NI_NUMERICSERV;
 196
 197         switch ((sa.ss.ss_family = r->idiag_family)) {
 198         case AF_INET: {
 199                 sa.in.sin_port = r->id.idiag_sport;
 200                 sa.in.sin_addr.s_addr = r->id.idiag_src[0];
 201                 keylen = INET_ADDRSTRLEN;
 202                 alloca_len = keylen + 1 + portlen;
 203                 key = alloca(alloca_len);
 204                 key[keylen] = 0; /* will be ':' later */
 205                 port = key + keylen + 1;
 206                 rc = getnameinfo(&sa.sa, len,
 207                                  key, keylen, port, portlen, flags);
 208                 break;
 209                 }
 210         case AF_INET6: {
 211                 sa.in6.sin6_port = r->id.idiag_sport;
 212                 memcpy(&sa.in6.sin6_addr, &r->id.idiag_src, sizeof(__be32[4]));
 213                 keylen = INET6_ADDRSTRLEN;
 214                           /* [            ] */
 215                 alloca_len = 1 + keylen + 1 + 1 + portlen;
 216                 key = alloca(alloca_len);
 217                 *key = '[';
 218                 key[1 + keylen + 1] = 0; /* will be ':' later */
 219                 port = 1 + key + keylen + 1 + 1;
 220                 rc = getnameinfo(&sa.sa, len,
 221                                  key + 1, keylen, port, portlen, flags);
 222                 break;
 223                 }
 224         default:
 225                 assert(0 && "unsupported address family, could that be IPv7?!");
 226         }
 227         if (rc != 0) {
 228                 fprintf(stderr, "BUG: getnameinfo: %s\n", gai_strerror(rc));
 229                 bug_warn();
 230                 *key = 0;
 231         }
 232
 233         keylen = strlen(key);
 234         portlen = strlen(port);
 235
 236         switch (sa.ss.ss_family) {
 237         case AF_INET:
 238                 key[keylen] = ':';
 239                 memmove(key + keylen + 1, port, portlen + 1);
 240                 break;
 241         case AF_INET6:
 242                 key[keylen] = ']';
 243                 key[keylen + 1] = ':';
 244                 memmove(key + keylen + 2, port, portlen + 1);
 245                 keylen++;
 246                 break;
 247         default:
 248                 assert(0 && "unsupported address family, could that be IPv7?!");
 249         }
 250
 251         if (st_lookup(table, (st_data_t)key, (st_data_t *)&stats))
 252                 return stats;
 253
 254         old_key = key;
 255
 256         if (r->idiag_state == TCP_ESTABLISHED) {
 257                 int n = snprintf(key, alloca_len, "%s:%u",
 258                                  addr_any(sa.ss.ss_family),
 259                                  ntohs(r->id.idiag_sport));
 260                 if (n <= 0) {
 261                         fprintf(stderr, "BUG: snprintf: %d\n", n);
 262                         bug_warn();
 263                 }
 264                 if (st_lookup(table, (st_data_t)key, (st_data_t *)&stats))
 265                         return stats;
 266                 if (n <= 0) {
 267                         key = xmalloc(1);
 268                         *key = '\0';
 269                 } else {
 270                         old_key = key;
 271                         key = xmalloc(n + 1);
 272                         memcpy(key, old_key, n + 1);
 273                 }
 274         } else {
 275                 key = xmalloc(keylen + 1 + portlen + 1);
 276                 memcpy(key, old_key, keylen + 1 + portlen + 1);
 277         }
 278         stats = xcalloc(1, sizeof(struct listen_stats));
 279         st_insert(table, (st_data_t)key, (st_data_t)stats);
 280         return stats;
 281 }
 282
 283 static void table_incr_active(st_table *table, struct inet_diag_msg *r)
 284 {
 285         struct listen_stats *stats = stats_for(table, r);
 286         ++stats->active;
 287 }
 288
 289 static void table_set_queued(st_table *table, struct inet_diag_msg *r)
 290 {
 291         struct listen_stats *stats = stats_for(table, r);
 292         stats->listener_p = 1;
 293         stats->queued = r->idiag_rqueue;
 294 }
 295
 296 /* inner loop of inet_diag, called for every socket returned by netlink */
 297 static inline void r_acc(struct nogvl_args *args, struct inet_diag_msg *r)
 298 {
 299         /*
 300          * inode == 0 means the connection is still in the listen queue
 301          * and has not yet been accept()-ed by the server.  The
 302          * inet_diag bytecode cannot filter this for us.
 303          */
 304         if (r->idiag_inode == 0)
 305                 return;
 306         if (r->idiag_state == TCP_ESTABLISHED) {
 307                 if (args->table)
 308                         table_incr_active(args->table, r);
 309                 else
 310                         args->stats.active++;
 311         } else { /* if (r->idiag_state == TCP_LISTEN) */
 312                 if (args->table)
 313                         table_set_queued(args->table, r);
 314                 else
 315                         args->stats.queued = r->idiag_rqueue;
 316         }
 317         /*
 318          * we wont get anything else because of the idiag_states filter
 319          */
 320 }
 321
 322 static const char err_sendmsg[] = "sendmsg";
 323 static const char err_recvmsg[] = "recvmsg";
 324 static const char err_nlmsg[] = "nlmsg";
 325
 326 struct diag_req {
 327         struct nlmsghdr nlh;
 328         struct inet_diag_req r;
 329 };
 330
 331 static void prep_msghdr(
 332         struct msghdr *msg,
 333         struct nogvl_args *args,
 334         struct sockaddr_nl *nladdr,
 335         size_t iovlen)
 336 {
 337         memset(msg, 0, sizeof(struct msghdr));
 338         msg->msg_name = (void *)nladdr;
 339         msg->msg_namelen = sizeof(struct sockaddr_nl);
 340         msg->msg_iov = args->iov;
 341         msg->msg_iovlen = iovlen;
 342 }
 343
 344 static void prep_diag_args(
 345         struct nogvl_args *args,
 346         struct sockaddr_nl *nladdr,
 347         struct rtattr *rta,
 348         struct diag_req *req,
 349         struct msghdr *msg)
 350 {
 351         memset(req, 0, sizeof(struct diag_req));
 352         memset(nladdr, 0, sizeof(struct sockaddr_nl));
 353
 354         nladdr->nl_family = AF_NETLINK;
 355
 356         req->nlh.nlmsg_len = sizeof(struct diag_req) +
 357                             RTA_LENGTH(args->iov[2].iov_len);
 358         req->nlh.nlmsg_type = TCPDIAG_GETSOCK;
 359         req->nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
 360         req->nlh.nlmsg_pid = getpid();
 361         req->r.idiag_states = (1<<TCP_ESTABLISHED) | (1<<TCP_LISTEN);
 362         rta->rta_type = INET_DIAG_REQ_BYTECODE;
 363         rta->rta_len = RTA_LENGTH(args->iov[2].iov_len);
 364
 365         args->iov[0].iov_base = req;
 366         args->iov[0].iov_len = sizeof(struct diag_req);
 367         args->iov[1].iov_base = rta;
 368         args->iov[1].iov_len = sizeof(struct rtattr);
 369
 370         prep_msghdr(msg, args, nladdr, 3);
 371 }
 372
 373 static void prep_recvmsg_buf(struct nogvl_args *args)
 374 {
 375         /* reuse buffer that was allocated for bytecode */
 376         args->iov[0].iov_len = page_size;
 377         args->iov[0].iov_base = args->iov[2].iov_base;
 378 }
 379
 380 /* does the inet_diag stuff with netlink(), this is called w/o GVL */
 381 static VALUE diag(void *ptr)
 382 {
 383         struct nogvl_args *args = ptr;
 384         struct sockaddr_nl nladdr;
 385         struct rtattr rta;
 386         struct diag_req req;
 387         struct msghdr msg;
 388         const char *err = NULL;
 389         unsigned seq = ++g_seq;
 390
 391         prep_diag_args(args, &nladdr, &rta, &req, &msg);
 392         req.nlh.nlmsg_seq = seq;
 393
 394         if (sendmsg(args->fd, &msg, 0) < 0) {
 395                 err = err_sendmsg;
 396                 goto out;
 397         }
 398
 399         prep_recvmsg_buf(args);
 400
 401         while (1) {
 402                 ssize_t readed;
 403                 size_t r;
 404                 struct nlmsghdr *h = (struct nlmsghdr *)args->iov[0].iov_base;
 405
 406                 prep_msghdr(&msg, args, &nladdr, 1);
 407                 readed = recvmsg(args->fd, &msg, 0);
 408                 if (readed < 0) {
 409                         if (errno == EINTR)
 410                                 continue;
 411                         err = err_recvmsg;
 412                         goto out;
 413                 }
 414                 if (readed == 0)
 415                         goto out;
 416                 r = (size_t)readed;
 417                 for ( ; NLMSG_OK(h, r); h = NLMSG_NEXT(h, r)) {
 418                         if (h->nlmsg_seq != seq)
 419                                 continue;
 420                         if (h->nlmsg_type == NLMSG_DONE)
 421                                 goto out;
 422                         if (h->nlmsg_type == NLMSG_ERROR) {
 423                                 err = err_nlmsg;
 424                                 goto out;
 425                         }
 426                         r_acc(args, NLMSG_DATA(h));
 427                 }
 428         }
 429 out:
 430         {
 431                 int save_errno = errno;
 432                 if (err && args->table) {
 433                         st_foreach(args->table, st_free_data, 0);
 434                         st_free_table(args->table);
 435                 }
 436                 errno = save_errno;
 437         }
 438         return (VALUE)err;
 439 }
 440
 441 /* populates sockaddr_storage struct by parsing +addr+ */
 442 static void parse_addr(union any_addr *inet, VALUE addr)
 443 {
 444         char *host_ptr;
 445         char *check;
 446         char *colon = NULL;
 447         char *rbracket = NULL;
 448         void *dst;
 449         long host_len;
 450         int af, rc;
 451         uint16_t *portdst;
 452         unsigned long port;
 453
 454         Check_Type(addr, T_STRING);
 455         host_ptr = StringValueCStr(addr);
 456         host_len = RSTRING_LEN(addr);
 457         if (*host_ptr == '[') { /* ipv6 address format (rfc2732) */
 458                 rbracket = memchr(host_ptr + 1, ']', host_len - 1);
 459
 460                 if (rbracket == NULL)
 461                         rb_raise(rb_eArgError, "']' not found in IPv6 addr=%s",
 462                                  host_ptr);
 463                 if (rbracket[1] != ':')
 464                         rb_raise(rb_eArgError, "':' not found in IPv6 addr=%s",
 465                                  host_ptr);
 466                 colon = rbracket + 1;
 467                 host_ptr++;
 468                 *rbracket = 0;
 469                 inet->ss.ss_family = af = AF_INET6;
 470                 dst = &inet->in6.sin6_addr;
 471                 portdst = &inet->in6.sin6_port;
 472         } else { /* ipv4 */
 473                 colon = memchr(host_ptr, ':', host_len);
 474                 inet->ss.ss_family = af = AF_INET;
 475                 dst = &inet->in.sin_addr;
 476                 portdst = &inet->in.sin_port;
 477         }
 478
 479         if (!colon)
 480                 rb_raise(rb_eArgError, "port not found in: `%s'", host_ptr);
 481         port = strtoul(colon + 1, &check, 10);
 482         *colon = 0;
 483         rc = inet_pton(af, host_ptr, dst);
 484         *colon = ':';
 485         if (rbracket) *rbracket = ']';
 486         if (*check || ((uint16_t)port != port))
 487                 rb_raise(rb_eArgError, "invalid port: %s", colon + 1);
 488         if (rc != 1)
 489                 rb_raise(rb_eArgError, "inet_pton failed for: `%s' with %d",
 490                          host_ptr, rc);
 491         *portdst = ntohs((uint16_t)port);
 492 }
 493
 494 /* generates inet_diag bytecode to match all addrs */
 495 static void gen_bytecode_all(struct iovec *iov)
 496 {
 497         struct inet_diag_bc_op *op;
 498         struct inet_diag_hostcond *cond;
 499
 500         /* iov_len was already set and base allocated in a parent function */
 501         assert(iov->iov_len == OPLEN && iov->iov_base && "iov invalid");
 502         op = iov->iov_base;
 503         op->code = INET_DIAG_BC_S_COND;
 504         op->yes = OPLEN;
 505         op->no = sizeof(struct inet_diag_bc_op) + OPLEN;
 506         cond = (struct inet_diag_hostcond *)(op + 1);
 507         cond->family = AF_UNSPEC;
 508         cond->port = -1;
 509         cond->prefix_len = 0;
 510 }
 511
 512 /* generates inet_diag bytecode to match a single addr */
 513 static void gen_bytecode(struct iovec *iov, union any_addr *inet)
 514 {
 515         struct inet_diag_bc_op *op;
 516         struct inet_diag_hostcond *cond;
 517
 518         /* iov_len was already set and base allocated in a parent function */
 519         assert(iov->iov_len == OPLEN && iov->iov_base && "iov invalid");
 520         op = iov->iov_base;
 521         op->code = INET_DIAG_BC_S_COND;
 522         op->yes = OPLEN;
 523         op->no = sizeof(struct inet_diag_bc_op) + OPLEN;
 524
 525         cond = (struct inet_diag_hostcond *)(op + 1);
 526         cond->family = inet->ss.ss_family;
 527         switch (inet->ss.ss_family) {
 528         case AF_INET: {
 529                 cond->port = ntohs(inet->in.sin_port);
 530                 cond->prefix_len = inet->in.sin_addr.s_addr == 0 ? 0 :
 531                                    sizeof(inet->in.sin_addr.s_addr) * CHAR_BIT;
 532                 *cond->addr = inet->in.sin_addr.s_addr;
 533                 }
 534                 break;
 535         case AF_INET6: {
 536                 cond->port = ntohs(inet->in6.sin6_port);
 537                 cond->prefix_len = memcmp(&in6addr_any, &inet->in6.sin6_addr,
 538                                           sizeof(struct in6_addr)) == 0 ?
 539                                   0 : sizeof(inet->in6.sin6_addr) * CHAR_BIT;
 540                 memcpy(&cond->addr, &inet->in6.sin6_addr,
 541                        sizeof(struct in6_addr));
 542                 }
 543                 break;
 544         default:
 545                 assert(0 && "unsupported address family, could that be IPv7?!");
 546         }
 547 }
 548
 549 static void nl_errcheck(VALUE r)
 550 {
 551         const char *err = (const char *)r;
 552
 553         if (err) {
 554                 if (err == err_nlmsg)
 555                         rb_raise(rb_eRuntimeError, "NLMSG_ERROR");
 556                 else
 557                         rb_sys_fail(err);
 558         }
 559 }
 560
 561 static VALUE tcp_stats(struct nogvl_args *args, VALUE addr)
 562 {
 563         union any_addr query_addr;
 564
 565         parse_addr(&query_addr, addr);
 566         gen_bytecode(&args->iov[2], &query_addr);
 567
 568         memset(&args->stats, 0, sizeof(struct listen_stats));
 569         nl_errcheck(rb_thread_io_blocking_region(diag, args, args->fd));
 570
 571         return rb_listen_stats(&args->stats);
 572 }
 573
 574 /*
 575  * call-seq:
 576  *      Raindrops::Linux.tcp_listener_stats([addrs[, sock]]) => hash
 577  *
 578  * If specified, +addr+ may be a string or array of strings representing
 579  * listen addresses to filter for. Returns a hash with given addresses as
 580  * keys and ListenStats objects as the values or a hash of all addresses.
 581  *
 582  *      addrs = %w(0.0.0.0:80 127.0.0.1:8080)
 583  *
 584  * If +addr+ is nil or not specified, all (IPv4) addresses are returned.
 585  * If +sock+ is specified, it should be a Raindrops::InetDiagSock object.
 586  */
 587 static VALUE tcp_listener_stats(int argc, VALUE *argv, VALUE self)
 588 {
 589         VALUE *ary;
 590         long i;
 591         VALUE rv = rb_hash_new();
 592         struct nogvl_args args;
 593         VALUE addrs, sock;
 594
 595         rb_scan_args(argc, argv, "02", &addrs, &sock);
 596
 597         /*
 598          * allocating page_size instead of OP_LEN since we'll reuse the
 599          * buffer for recvmsg() later, we already checked for
 600          * OPLEN <= page_size at initialization
 601          */
 602         args.iov[2].iov_len = OPLEN;
 603         args.iov[2].iov_base = alloca(page_size);
 604         args.table = NULL;
 605         if (NIL_P(sock))
 606                 sock = rb_funcall(cIDSock, id_new, 0);
 607         args.fd = my_fileno(sock);
 608
 609         switch (TYPE(addrs)) {
 610         case T_STRING:
 611                 rb_hash_aset(rv, addrs, tcp_stats(&args, addrs));
 612                 return rv;
 613         case T_ARRAY:
 614                 ary = RARRAY_PTR(addrs);
 615                 i = RARRAY_LEN(addrs);
 616                 if (i == 1) {
 617                         rb_hash_aset(rv, *ary, tcp_stats(&args, *ary));
 618                         return rv;
 619                 }
 620                 for (; --i >= 0; ary++) {
 621                         union any_addr check;
 622
 623                         parse_addr(&check, *ary);
 624                         rb_hash_aset(rv, *ary, Qtrue);
 625                 }
 626                 /* fall through */
 627         case T_NIL:
 628                 args.table = st_init_strtable();
 629                 gen_bytecode_all(&args.iov[2]);
 630                 break;
 631         default:
 632                 rb_raise(rb_eArgError,
 633                          "addr must be an array of strings, a string, or nil");
 634         }
 635
 636         nl_errcheck(rb_thread_io_blocking_region(diag, &args, args.fd));
 637
 638         st_foreach(args.table, NIL_P(addrs) ? st_to_hash : st_AND_hash, rv);
 639         st_free_table(args.table);
 640
 641         /* let GC deal with corner cases */
 642         if (argc < 2) rb_io_close(sock);
 643         return rv;
 644 }
 645
 646 void Init_raindrops_linux_inet_diag(void)
 647 {
 648         VALUE cRaindrops = rb_const_get(rb_cObject, rb_intern("Raindrops"));
 649         VALUE mLinux = rb_define_module_under(cRaindrops, "Linux");
 650
 651         rb_require("socket");
 652         cIDSock = rb_const_get(rb_cObject, rb_intern("Socket"));
 653         id_new = rb_intern("new");
 654
 655         /*
 656          * Document-class: Raindrops::InetDiagSocket
 657          *
 658          * This is a subclass of +Socket+ specifically for talking
 659          * to the inet_diag facility of Netlink.
 660          */
 661         cIDSock = rb_define_class_under(cRaindrops, "InetDiagSocket", cIDSock);
 662         rb_define_singleton_method(cIDSock, "new", ids_s_new, 0);
 663
 664         cListenStats = rb_const_get(cRaindrops, rb_intern("ListenStats"));
 665
 666         rb_define_module_function(mLinux, "tcp_listener_stats",
 667                                   tcp_listener_stats, -1);
 668
 669         page_size = getpagesize();
 670
 671         assert(OPLEN <= page_size && "bytecode OPLEN is not <= PAGE_SIZE");
 672 }
 673 #endif /* __linux__ */