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                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
  76                                    (char *)&on, sizeof(on));
  77                 }
  78 #endif /* IPV6_V6ONLY */
  79         }
  80 #endif /* HAVE_STRUCT_SOCKADDR_IN6 */
  81
  82         if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) {
  83                 fr_strerror_printf("Failed in setsockopt(): %s", strerror(errno));
  84                 close(sockfd);
  85                 return -1;
  86         }
  87
  88         if (bind(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
  89                 fr_strerror_printf("Failed in bind(): %s", strerror(errno));
  90                 close(sockfd);
  91                 return -1;
  92         }
  93
  94         if (listen(sockfd, 8) < 0) {
  95                 fr_strerror_printf("Failed in listen(): %s", strerror(errno));
  96                 close(sockfd);
  97                 return -1;
  98         }
  99
 100         return sockfd;
 101 }
 102
 103
 104 /*
 105  *      Open a socket TO the given IP and port.
 106  */
 107 int fr_tcp_client_socket(fr_ipaddr_t *src_ipaddr,
 108                          fr_ipaddr_t *dst_ipaddr, int dst_port)
 109 {
 110         int sockfd;
 111         struct sockaddr_storage salocal;
 112         socklen_t       salen;
 113
 114         if ((dst_port < 0) || (dst_port > 65535)) {
 115                 fr_strerror_printf("Port %d is out of allowed bounds",
 116                                    dst_port);
 117                 return -1;
 118         }
 119
 120         if (!dst_ipaddr) return -1;
 121
 122         sockfd = socket(dst_ipaddr->af, SOCK_STREAM, 0);
 123         if (sockfd < 0) {
 124                 return sockfd;
 125         }
 126
 127 #if 0
 128 #ifdef O_NONBLOCK
 129         {
 130                 int flags;
 131
 132                 if ((flags = fcntl(sockfd, F_GETFL, NULL)) < 0)  {
 133                         fr_strerror_printf("Failure getting socket flags: %s",
 134                                    strerror(errno));
 135                         close(sockfd);
 136                         return -1;
 137                 }
 138
 139                 flags |= O_NONBLOCK;
 140                 if( fcntl(sockfd, F_SETFL, flags) < 0) {
 141                         fr_strerror_printf("Failure setting socket flags: %s",
 142                                    strerror(errno));
 143                         close(sockfd);
 144                         return -1;
 145                 }
 146         }
 147 #endif
 148 #endif
 149         /*
 150          *      Allow the caller to bind us to a specific source IP.
 151          */
 152         if (src_ipaddr && (src_ipaddr->af != AF_UNSPEC)) {
 153                 if (!fr_ipaddr2sockaddr(src_ipaddr, 0, &salocal, &salen)) {
 154                         close(sockfd);
 155                         return -1;
 156                 }
 157
 158                 if (bind(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
 159                         fr_strerror_printf("Failure binding to IP: %s",
 160                                            strerror(errno));
 161                         close(sockfd);
 162                         return -1;
 163                 }
 164         }
 165
 166         if (!fr_ipaddr2sockaddr(dst_ipaddr, dst_port, &salocal, &salen)) {
 167                         close(sockfd);
 168                 return -1;
 169         }
 170
 171         /*
 172          *      FIXME: If EINPROGRESS, then tell the caller that
 173          *      somehow.  The caller can then call connect() when the
 174          *      socket is ready...
 175          */
 176         if (connect(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
 177                 fr_strerror_printf("Failed in connect(): %s", strerror(errno));
 178                 close(sockfd);
 179                 return -1;
 180         }
 181
 182         return sockfd;
 183 }
 184
 185
 186 RADIUS_PACKET *fr_tcp_recv(int sockfd, int flags)
 187 {
 188         RADIUS_PACKET *packet = rad_alloc(0);
 189
 190         if (!packet) return NULL;
 191
 192         packet->sockfd = sockfd;
 193
 194         if (fr_tcp_read_packet(packet, flags) != 1) {
 195                 rad_free(&packet);
 196                 return NULL;
 197         }
 198
 199         return packet;
 200 }
 201
 202
 203 /*
 204  *      Receives a packet, assuming that the RADIUS_PACKET structure
 205  *      has been filled out already.
 206  *
 207  *      This ASSUMES that the packet is allocated && fields
 208  *      initialized.
 209  *
 210  *      This ASSUMES that the socket is marked as O_NONBLOCK, which
 211  *      the function above does set, if your system supports it.
 212  *
 213  *      Calling this function MAY change sockfd,
 214  *      if src_ipaddr.af == AF_UNSPEC.
 215  */
 216 int fr_tcp_read_packet(RADIUS_PACKET *packet, int flags)
 217 {
 218         ssize_t len;
 219
 220         /*
 221          *      No data allocated.  Read the 4-byte header into
 222          *      a temporary buffer.
 223          */
 224         if (!packet->data) {
 225                 int packet_len;
 226
 227                 len = recv(packet->sockfd, packet->vector + packet->data_len,
 228                            4 - packet->data_len, 0);
 229                 if (len == 0) return -2; /* clean close */
 230
 231 #ifdef ECONNRESET
 232                 if ((len < 0) && (errno == ECONNRESET)) { /* forced */
 233                         return -2;
 234                 }
 235 #endif
 236
 237                 if (len < 0) {
 238                         fr_strerror_printf("Error receiving packet: %s",
 239                                    strerror(errno));
 240                         return -1;
 241                 }
 242
 243                 packet->data_len += len;
 244                 if (packet->data_len < 4) { /* want more data */
 245                         return 0;
 246                 }
 247
 248                 packet_len = (packet->vector[2] << 8) | packet->vector[3];
 249
 250                 if (packet_len < AUTH_HDR_LEN) {
 251                         fr_strerror_printf("Discarding packet: Smaller than RFC minimum of 20 bytes.");
 252                         return -1;
 253                 }
 254
 255                 /*
 256                  *      If the packet is too big, then the socket is bad.
 257                  */
 258                 if (packet_len > MAX_PACKET_LEN) {
 259                         fr_strerror_printf("Discarding packet: Larger than RFC limitation of 4096 bytes.");
 260                         return -1;
 261                 }
 262
 263                 packet->data = malloc(packet_len);
 264                 if (!packet->data) {
 265                         fr_strerror_printf("Out of memory");
 266                         return -1;
 267                 }
 268
 269                 packet->data_len = packet_len;
 270                 packet->partial = 4;
 271                 memcpy(packet->data, packet->vector, 4);
 272         }
 273
 274         /*
 275          *      Try to read more data.
 276          */
 277         len = recv(packet->sockfd, packet->data + packet->partial,
 278                    packet->data_len - packet->partial, 0);
 279         if (len == 0) return -2; /* clean close */
 280
 281 #ifdef ECONNRESET
 282         if ((len < 0) && (errno == ECONNRESET)) { /* forced */
 283                 return -2;
 284         }
 285 #endif
 286
 287         if (len < 0) {
 288                 fr_strerror_printf("Error receiving packet: %s", strerror(errno));
 289                 return -1;
 290         }
 291
 292         packet->partial += len;
 293
 294         if (packet->partial < packet->data_len) {
 295                 return 0;
 296         }
 297
 298         /*
 299          *      See if it's a well-formed RADIUS packet.
 300          */
 301         if (!rad_packet_ok(packet, flags)) {
 302                 return -1;
 303         }
 304
 305         /*
 306          *      Explicitly set the VP list to empty.
 307          */
 308         packet->vps = NULL;
 309
 310         if (fr_debug_flag) {
 311                 char ip_buf[128], buffer[256];
 312
 313                 if (packet->src_ipaddr.af != AF_UNSPEC) {
 314                         inet_ntop(packet->src_ipaddr.af,
 315                                   &packet->src_ipaddr.ipaddr,
 316                                   ip_buf, sizeof(ip_buf));
 317                         snprintf(buffer, sizeof(buffer), "host %s port %d",
 318                                  ip_buf, packet->src_port);
 319                 } else {
 320                         snprintf(buffer, sizeof(buffer), "socket %d",
 321                                  packet->sockfd);
 322                 }
 323
 324
 325                 if ((packet->code > 0) && (packet->code < FR_MAX_PACKET_CODE)) {
 326                         DEBUG("rad_recv: %s packet from %s",
 327                               fr_packet_codes[packet->code], buffer);
 328                 } else {
 329                         DEBUG("rad_recv: Packet from %s code=%d",
 330                               buffer, packet->code);
 331                 }
 332                 DEBUG(", id=%d, length=%zd\n", packet->id, packet->data_len);
 333         }
 334
 335         return 1;               /* done reading the packet */
 336 }
 337
 338 RADIUS_PACKET *fr_tcp_accept(int sockfd)
 339 {
 340         int newfd;
 341         socklen_t salen;
 342         RADIUS_PACKET *packet;
 343         struct sockaddr_storage src;
 344
 345         salen = sizeof(src);
 346
 347         newfd = accept(sockfd, (struct sockaddr *) &src, &salen);
 348         if (newfd < 0) {
 349                 /*
 350                  *      Non-blocking sockets must handle this.
 351                  */
 352 #ifdef EWOULDBLOCK
 353                 if (errno == EWOULDBLOCK) {
 354                         packet = rad_alloc(0);
 355                         if (!packet) return NULL;
 356
 357                         packet->sockfd = sockfd;
 358                         packet->src_ipaddr.af = AF_UNSPEC;
 359                         return packet;
 360                 }
 361 #endif
 362
 363                 return NULL;
 364         }
 365
 366         packet = rad_alloc(0);
 367         if (!packet) return NULL;
 368
 369         if (src.ss_family == AF_INET) {
 370                 struct sockaddr_in      s4;
 371
 372                 memcpy(&s4, &src, sizeof(s4));
 373                 packet->src_ipaddr.af = AF_INET;
 374                 packet->src_ipaddr.ipaddr.ip4addr = s4.sin_addr;
 375                 packet->src_port = ntohs(s4.sin_port);
 376
 377 #ifdef HAVE_STRUCT_SOCKADDR_IN6
 378         } else if (src.ss_family == AF_INET6) {
 379                 struct sockaddr_in6     s6;
 380
 381                 memcpy(&s6, &src, sizeof(s6));
 382                 packet->src_ipaddr.af = AF_INET6;
 383                 packet->src_ipaddr.ipaddr.ip6addr = s6.sin6_addr;
 384                 packet->src_port = ntohs(s6.sin6_port);
 385
 386 #endif
 387         } else {
 388                 rad_free(&packet);
 389                 return NULL;
 390         }
 391
 392         packet->sockfd = newfd;
 393
 394         /*
 395          *      Note: Caller has to set dst_ipaddr && dst_port.
 396          */
 397         return packet;
 398 }
 399
 400
 401 /*
 402  *      Writes a packet, assuming it's already been encoded.
 403  *
 404  *      It returns the number of bytes written, which MAY be less than
 405  *      the packet size (data_len).  It is the caller's responsibility
 406  *      to check the return code, and to schedule writes again.
 407  */
 408 ssize_t fr_tcp_write_packet(RADIUS_PACKET *packet)
 409 {
 410         ssize_t rcode;
 411
 412         if (!packet || !packet->data) return 0;
 413
 414         if (packet->partial >= packet->data_len) return packet->data_len;
 415
 416         rcode = write(packet->sockfd, packet->data + packet->partial,
 417                       packet->data_len - packet->partial);
 418         if (rcode < 0) return packet->partial; /* ignore most errors */
 419
 420         packet->partial += rcode;
 421
 422         return packet->partial;
 423 }
 424 #endif /* WITH_TCP */