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) || /* clean close */
 230                     ((len < 0) && (errno == ECONNRESET))) { /* forced */
 231                         return -2;
 232                 }
 233
 234                 if (len < 0) {
 235                         fr_strerror_printf("Error receiving packet: %s",
 236                                    strerror(errno));
 237                         return -1;
 238                 }
 239
 240                 packet->data_len += len;
 241                 if (packet->data_len < 4) { /* want more data */
 242                         return 0;
 243                 }
 244
 245                 packet_len = (packet->vector[2] << 8) | packet->vector[3];
 246
 247                 if (packet_len < AUTH_HDR_LEN) {
 248                         fr_strerror_printf("Discarding packet: Smaller than RFC minimum of 20 bytes.");
 249                         return -1;
 250                 }
 251
 252                 /*
 253                  *      If the packet is too big, then the socket is bad.
 254                  */
 255                 if (packet_len > MAX_PACKET_LEN) {
 256                         fr_strerror_printf("Discarding packet: Larger than RFC limitation of 4096 bytes.");
 257                         return -1;
 258                 }
 259
 260                 packet->data = malloc(packet_len);
 261                 if (!packet->data) {
 262                         fr_strerror_printf("Out of memory");
 263                         return -1;
 264                 }
 265
 266                 packet->data_len = packet_len;
 267                 packet->partial = 4;
 268                 memcpy(packet->data, packet->vector, 4);
 269         }
 270
 271         /*
 272          *      Try to read more data.
 273          */
 274         len = recv(packet->sockfd, packet->data + packet->partial,
 275                    packet->data_len - packet->partial, 0);
 276         if ((len == 0) || /* clean close */
 277             ((len < 0) && (errno == ECONNRESET))) { /* forced */
 278           return -2;
 279         }
 280
 281         if (len < 0) {
 282                 fr_strerror_printf("Error receiving packet: %s", strerror(errno));
 283                 return -1;
 284         }
 285
 286         packet->partial += len;
 287
 288         if (packet->partial < packet->data_len) {
 289                 return 0;
 290         }
 291
 292         /*
 293          *      See if it's a well-formed RADIUS packet.
 294          */
 295         if (!rad_packet_ok(packet, flags)) {
 296                 return -1;
 297         }
 298
 299         /*
 300          *      Explicitly set the VP list to empty.
 301          */
 302         packet->vps = NULL;
 303
 304         if (fr_debug_flag) {
 305                 char ip_buf[128], buffer[256];
 306
 307                 if (packet->src_ipaddr.af != AF_UNSPEC) {
 308                         inet_ntop(packet->src_ipaddr.af,
 309                                   &packet->src_ipaddr.ipaddr,
 310                                   ip_buf, sizeof(ip_buf));
 311                         snprintf(buffer, sizeof(buffer), "host %s port %d",
 312                                  ip_buf, packet->src_port);
 313                 } else {
 314                         snprintf(buffer, sizeof(buffer), "socket %d",
 315                                  packet->sockfd);
 316                 }
 317
 318
 319                 if ((packet->code > 0) && (packet->code < FR_MAX_PACKET_CODE)) {
 320                         DEBUG("rad_recv: %s packet from %s",
 321                               fr_packet_codes[packet->code], buffer);
 322                 } else {
 323                         DEBUG("rad_recv: Packet from %s code=%d",
 324                               buffer, packet->code);
 325                 }
 326                 DEBUG(", id=%d, length=%ld\n", packet->id, packet->data_len);
 327         }
 328
 329         return 1;               /* done reading the packet */
 330 }
 331
 332 RADIUS_PACKET *fr_tcp_accept(int sockfd)
 333 {
 334         int newfd;
 335         socklen_t salen;
 336         RADIUS_PACKET *packet;
 337         struct sockaddr_storage src;
 338
 339         salen = sizeof(src);
 340
 341         newfd = accept(sockfd, (struct sockaddr *) &src, &salen);
 342         if (newfd < 0) {
 343                 /*
 344                  *      Non-blocking sockets must handle this.
 345                  */
 346                 if (errno == EWOULDBLOCK) {
 347                         packet = rad_alloc(0);
 348                         if (!packet) return NULL;
 349
 350                         packet->sockfd = sockfd;
 351                         packet->src_ipaddr.af = AF_UNSPEC;
 352                         return packet;
 353                 }
 354
 355                 return NULL;
 356         }
 357
 358         packet = rad_alloc(0);
 359         if (!packet) return NULL;
 360
 361         if (src.ss_family == AF_INET) {
 362                 struct sockaddr_in      s4;
 363
 364                 memcpy(&s4, &src, sizeof(s4));
 365                 packet->src_ipaddr.af = AF_INET;
 366                 packet->src_ipaddr.ipaddr.ip4addr = s4.sin_addr;
 367                 packet->src_port = ntohs(s4.sin_port);
 368
 369 #ifdef HAVE_STRUCT_SOCKADDR_IN6
 370         } else if (src.ss_family == AF_INET6) {
 371                 struct sockaddr_in6     s6;
 372
 373                 memcpy(&s6, &src, sizeof(s6));
 374                 packet->src_ipaddr.af = AF_INET6;
 375                 packet->src_ipaddr.ipaddr.ip6addr = s6.sin6_addr;
 376                 packet->src_port = ntohs(s6.sin6_port);
 377
 378 #endif
 379         } else {
 380                 rad_free(&packet);
 381                 return NULL;
 382         }
 383
 384         packet->sockfd = newfd;
 385
 386         /*
 387          *      Note: Caller has to set dst_ipaddr && dst_port.
 388          */
 389         return packet;
 390 }
 391
 392
 393 /*
 394  *      Writes a packet, assuming it's already been encoded.
 395  *
 396  *      It returns the number of bytes written, which MAY be less than
 397  *      the packet size (data_len).  It is the caller's responsibility
 398  *      to check the return code, and to schedule writes again.
 399  */
 400 ssize_t fr_tcp_write_packet(RADIUS_PACKET *packet)
 401 {
 402         ssize_t rcode;
 403
 404         if (!packet || !packet->data) return 0;
 405
 406         if (packet->partial >= packet->data_len) return packet->data_len;
 407
 408         rcode = write(packet->sockfd, packet->data + packet->partial,
 409                       packet->data_len - packet->partial);
 410         if (rcode < 0) return packet->partial; /* ignore most errors */
 411
 412         packet->partial += rcode;
 413
 414         return packet->partial;
 415 }
 416 #endif /* WITH_TCP */