src/lib/tcp.c

   1 /*
   2  * tcp.c        TCP-specific functions.
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * Copyright (C) 2009 Dante http://dante.net
  21  */
  22
  23 #include        <freeradius-devel/ident.h>
  24 RCSID("$Id$")
  25
  26 #include        <freeradius-devel/libradius.h>
  27 #include        <freeradius-devel/tcp.h>
  28
  29 #ifdef WITH_TCP
  30
  31 /* FIXME: into common RADIUS header? */
  32 #define MAX_PACKET_LEN 4096
  33
  34 /*
  35  *      Open a socket on the given IP and port.
  36  */
  37 int fr_tcp_socket(fr_ipaddr_t *ipaddr, int port)
  38 {
  39         int sockfd;
  40         int on = 1;
  41         struct sockaddr_storage salocal;
  42         socklen_t       salen;
  43
  44         if ((port < 0) || (port > 65535)) {
  45                 fr_strerror_printf("Port %d is out of allowed bounds", port);
  46                 return -1;
  47         }
  48
  49         sockfd = socket(ipaddr->af, SOCK_STREAM, 0);
  50         if (sockfd < 0) {
  51                 return sockfd;
  52         }
  53
  54         if (fr_nonblock(sockfd) < 0) {
  55                 close(sockfd);
  56                 return -1;
  57         }
  58
  59         if (!fr_ipaddr2sockaddr(ipaddr, port, &salocal, &salen)) {
  60                 close(sockfd);
  61                 return -1;
  62         }
  63
  64 #ifdef HAVE_STRUCT_SOCKADDR_IN6
  65         if (ipaddr->af == AF_INET6) {
  66                 /*
  67                  *      Listening on '::' does NOT get you IPv4 to
  68                  *      IPv6 mapping.  You've got to listen on an IPv4
  69                  *      address, too.  This makes the rest of the server
  70                  *      design a little simpler.
  71                  */
  72 #ifdef IPV6_V6ONLY
  73
  74                 if (IN6_IS_ADDR_UNSPECIFIED(&ipaddr->ipaddr.ip6addr)) {
  75                         if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
  76                                        (char *)&on, sizeof(on)) < 0) {
  77                                 fr_strerror_printf("Failed in setsockopt(): %s",
  78                                                    strerror(errno));
  79                                 close(sockfd);
  80                                 return -1;
  81                         }
  82                 }
  83 #endif /* IPV6_V6ONLY */
  84         }
  85 #endif /* HAVE_STRUCT_SOCKADDR_IN6 */
  86
  87         if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) {
  88                 fr_strerror_printf("Failed in setsockopt(): %s", strerror(errno));
  89                 close(sockfd);
  90                 return -1;
  91         }
  92
  93         if (bind(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
  94                 fr_strerror_printf("Failed in bind(): %s", strerror(errno));
  95                 close(sockfd);
  96                 return -1;
  97         }
  98
  99         if (listen(sockfd, 8) < 0) {
 100                 fr_strerror_printf("Failed in listen(): %s", strerror(errno));
 101                 close(sockfd);
 102                 return -1;
 103         }
 104
 105         return sockfd;
 106 }
 107
 108
 109 /*
 110  *      Open a socket TO the given IP and port.
 111  */
 112 int fr_tcp_client_socket(fr_ipaddr_t *src_ipaddr,
 113                          fr_ipaddr_t *dst_ipaddr, int dst_port)
 114 {
 115         int sockfd;
 116         struct sockaddr_storage salocal;
 117         socklen_t       salen;
 118
 119         if ((dst_port < 0) || (dst_port > 65535)) {
 120                 fr_strerror_printf("Port %d is out of allowed bounds",
 121                                    dst_port);
 122                 return -1;
 123         }
 124
 125         if (!dst_ipaddr) return -1;
 126
 127         sockfd = socket(dst_ipaddr->af, SOCK_STREAM, 0);
 128         if (sockfd < 0) {
 129                 return sockfd;
 130         }
 131
 132 #if 0
 133 #ifdef O_NONBLOCK
 134         {
 135                 int flags;
 136
 137                 if ((flags = fcntl(sockfd, F_GETFL, NULL)) < 0)  {
 138                         fr_strerror_printf("Failure getting socket flags: %s",
 139                                    strerror(errno));
 140                         close(sockfd);
 141                         return -1;
 142                 }
 143
 144                 flags |= O_NONBLOCK;
 145                 if( fcntl(sockfd, F_SETFL, flags) < 0) {
 146                         fr_strerror_printf("Failure setting socket flags: %s",
 147                                    strerror(errno));
 148                         close(sockfd);
 149                         return -1;
 150                 }
 151         }
 152 #endif
 153 #endif
 154         /*
 155          *      Allow the caller to bind us to a specific source IP.
 156          */
 157         if (src_ipaddr && (src_ipaddr->af != AF_UNSPEC)) {
 158                 if (!fr_ipaddr2sockaddr(src_ipaddr, 0, &salocal, &salen)) {
 159                         close(sockfd);
 160                         return -1;
 161                 }
 162
 163                 if (bind(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
 164                         fr_strerror_printf("Failure binding to IP: %s",
 165                                            strerror(errno));
 166                         close(sockfd);
 167                         return -1;
 168                 }
 169         }
 170
 171         if (!fr_ipaddr2sockaddr(dst_ipaddr, dst_port, &salocal, &salen)) {
 172                         close(sockfd);
 173                 return -1;
 174         }
 175
 176         /*
 177          *      FIXME: If EINPROGRESS, then tell the caller that
 178          *      somehow.  The caller can then call connect() when the
 179          *      socket is ready...
 180          */
 181         if (connect(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
 182                 fr_strerror_printf("Failed in connect(): %s", strerror(errno));
 183                 close(sockfd);
 184                 return -1;
 185         }
 186
 187         return sockfd;
 188 }
 189
 190
 191 RADIUS_PACKET *fr_tcp_recv(int sockfd, int flags)
 192 {
 193         RADIUS_PACKET *packet = rad_alloc(NULL, 0);
 194
 195         if (!packet) return NULL;
 196
 197         packet->sockfd = sockfd;
 198
 199         if (fr_tcp_read_packet(packet, flags) != 1) {
 200                 rad_free(&packet);
 201                 return NULL;
 202         }
 203
 204         return packet;
 205 }
 206
 207
 208 /*
 209  *      Receives a packet, assuming that the RADIUS_PACKET structure
 210  *      has been filled out already.
 211  *
 212  *      This ASSUMES that the packet is allocated && fields
 213  *      initialized.
 214  *
 215  *      This ASSUMES that the socket is marked as O_NONBLOCK, which
 216  *      the function above does set, if your system supports it.
 217  *
 218  *      Calling this function MAY change sockfd,
 219  *      if src_ipaddr.af == AF_UNSPEC.
 220  */
 221 int fr_tcp_read_packet(RADIUS_PACKET *packet, int flags)
 222 {
 223         ssize_t len;
 224
 225         /*
 226          *      No data allocated.  Read the 4-byte header into
 227          *      a temporary buffer.
 228          */
 229         if (!packet->data) {
 230                 int packet_len;
 231
 232                 len = recv(packet->sockfd, packet->vector + packet->data_len,
 233                            4 - packet->data_len, 0);
 234                 if (len == 0) return -2; /* clean close */
 235
 236 #ifdef ECONNRESET
 237                 if ((len < 0) && (errno == ECONNRESET)) { /* forced */
 238                         return -2;
 239                 }
 240 #endif
 241
 242                 if (len < 0) {
 243                         fr_strerror_printf("Error receiving packet: %s",
 244                                    strerror(errno));
 245                         return -1;
 246                 }
 247
 248                 packet->data_len += len;
 249                 if (packet->data_len < 4) { /* want more data */
 250                         return 0;
 251                 }
 252
 253                 packet_len = (packet->vector[2] << 8) | packet->vector[3];
 254
 255                 if (packet_len < AUTH_HDR_LEN) {
 256                         fr_strerror_printf("Discarding packet: Smaller than RFC minimum of 20 bytes.");
 257                         return -1;
 258                 }
 259
 260                 /*
 261                  *      If the packet is too big, then the socket is bad.
 262                  */
 263                 if (packet_len > MAX_PACKET_LEN) {
 264                         fr_strerror_printf("Discarding packet: Larger than RFC limitation of 4096 bytes.");
 265                         return -1;
 266                 }
 267
 268                 packet->data = talloc_array(packet, uint8_t, packet_len);
 269                 if (!packet->data) {
 270                         fr_strerror_printf("Out of memory");
 271                         return -1;
 272                 }
 273
 274                 packet->data_len = packet_len;
 275                 packet->partial = 4;
 276                 memcpy(packet->data, packet->vector, 4);
 277         }
 278
 279         /*
 280          *      Try to read more data.
 281          */
 282         len = recv(packet->sockfd, packet->data + packet->partial,
 283                    packet->data_len - packet->partial, 0);
 284         if (len == 0) return -2; /* clean close */
 285
 286 #ifdef ECONNRESET
 287         if ((len < 0) && (errno == ECONNRESET)) { /* forced */
 288                 return -2;
 289         }
 290 #endif
 291
 292         if (len < 0) {
 293                 fr_strerror_printf("Error receiving packet: %s", strerror(errno));
 294                 return -1;
 295         }
 296
 297         packet->partial += len;
 298
 299         if (packet->partial < packet->data_len) {
 300                 return 0;
 301         }
 302
 303         /*
 304          *      See if it's a well-formed RADIUS packet.
 305          */
 306         if (!rad_packet_ok(packet, flags)) {
 307                 return -1;
 308         }
 309
 310         /*
 311          *      Explicitly set the VP list to empty.
 312          */
 313         packet->vps = NULL;
 314
 315         if (fr_debug_flag) {
 316                 char ip_buf[128], buffer[256];
 317
 318                 if (packet->src_ipaddr.af != AF_UNSPEC) {
 319                         inet_ntop(packet->src_ipaddr.af,
 320                                   &packet->src_ipaddr.ipaddr,
 321                                   ip_buf, sizeof(ip_buf));
 322                         snprintf(buffer, sizeof(buffer), "host %s port %d",
 323                                  ip_buf, packet->src_port);
 324                 } else {
 325                         snprintf(buffer, sizeof(buffer), "socket %d",
 326                                  packet->sockfd);
 327                 }
 328
 329
 330                 if ((packet->code > 0) && (packet->code < FR_MAX_PACKET_CODE)) {
 331                         DEBUG("rad_recv: %s packet from %s",
 332                               fr_packet_codes[packet->code], buffer);
 333                 } else {
 334                         DEBUG("rad_recv: Packet from %s code=%d",
 335                               buffer, packet->code);
 336                 }
 337                 DEBUG(", id=%d, length=%zu\n", packet->id, packet->data_len);
 338         }
 339
 340         return 1;               /* done reading the packet */
 341 }
 342
 343 RADIUS_PACKET *fr_tcp_accept(int sockfd)
 344 {
 345         int newfd;
 346         socklen_t salen;
 347         RADIUS_PACKET *packet;
 348         struct sockaddr_storage src;
 349
 350         salen = sizeof(src);
 351
 352         newfd = accept(sockfd, (struct sockaddr *) &src, &salen);
 353         if (newfd < 0) {
 354                 /*
 355                  *      Non-blocking sockets must handle this.
 356                  */
 357 #ifdef EWOULDBLOCK
 358                 if (errno == EWOULDBLOCK) {
 359                         packet = rad_alloc(NULL, 0);
 360                         if (!packet) return NULL;
 361
 362                         packet->sockfd = sockfd;
 363                         packet->src_ipaddr.af = AF_UNSPEC;
 364                         return packet;
 365                 }
 366 #endif
 367
 368                 return NULL;
 369         }
 370
 371         packet = rad_alloc(NULL, 0);
 372         if (!packet) {
 373                 close(newfd);
 374                 return NULL;
 375         }
 376
 377         if (src.ss_family == AF_INET) {
 378                 struct sockaddr_in      s4;
 379
 380                 memcpy(&s4, &src, sizeof(s4));
 381                 packet->src_ipaddr.af = AF_INET;
 382                 packet->src_ipaddr.ipaddr.ip4addr = s4.sin_addr;
 383                 packet->src_port = ntohs(s4.sin_port);
 384
 385 #ifdef HAVE_STRUCT_SOCKADDR_IN6
 386         } else if (src.ss_family == AF_INET6) {
 387                 struct sockaddr_in6     s6;
 388
 389                 memcpy(&s6, &src, sizeof(s6));
 390                 packet->src_ipaddr.af = AF_INET6;
 391                 packet->src_ipaddr.ipaddr.ip6addr = s6.sin6_addr;
 392                 packet->src_port = ntohs(s6.sin6_port);
 393
 394 #endif
 395         } else {
 396                 rad_free(&packet);
 397                 close(newfd);
 398                 return NULL;
 399         }
 400
 401         packet->sockfd = newfd;
 402
 403         /*
 404          *      Note: Caller has to set dst_ipaddr && dst_port.
 405          */
 406         return packet;
 407 }
 408
 409
 410 /*
 411  *      Writes a packet, assuming it's already been encoded.
 412  *
 413  *      It returns the number of bytes written, which MAY be less than
 414  *      the packet size (data_len).  It is the caller's responsibility
 415  *      to check the return code, and to schedule writes again.
 416  */
 417 ssize_t fr_tcp_write_packet(RADIUS_PACKET *packet)
 418 {
 419         ssize_t rcode;
 420
 421         if (!packet || !packet->data) return 0;
 422
 423         if (packet->partial >= packet->data_len) return packet->data_len;
 424
 425         rcode = write(packet->sockfd, packet->data + packet->partial,
 426                       packet->data_len - packet->partial);
 427         if (rcode < 0) return packet->partial; /* ignore most errors */
 428
 429         packet->partial += rcode;
 430
 431         return packet->partial;
 432 }
 433 #endif /* WITH_TCP */