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 RCSID("$Id$")
  24
  25 #include        <freeradius-devel/libradius.h>
  26
  27 #ifdef WITH_TCP
  28
  29 /* FIXME: into common RADIUS header? */
  30 #define MAX_PACKET_LEN 4096
  31
  32 RADIUS_PACKET *fr_tcp_recv(int sockfd, int flags)
  33 {
  34         RADIUS_PACKET *packet = rad_alloc(NULL, false);
  35
  36         if (!packet) return NULL;
  37
  38         packet->sockfd = sockfd;
  39
  40         if (fr_tcp_read_packet(packet, flags) != 1) {
  41                 rad_free(&packet);
  42                 return NULL;
  43         }
  44
  45         return packet;
  46 }
  47
  48
  49 /*
  50  *      Receives a packet, assuming that the RADIUS_PACKET structure
  51  *      has been filled out already.
  52  *
  53  *      This ASSUMES that the packet is allocated && fields
  54  *      initialized.
  55  *
  56  *      This ASSUMES that the socket is marked as O_NONBLOCK, which
  57  *      the function above does set, if your system supports it.
  58  *
  59  *      Calling this function MAY change sockfd,
  60  *      if src_ipaddr.af == AF_UNSPEC.
  61  */
  62 int fr_tcp_read_packet(RADIUS_PACKET *packet, int flags)
  63 {
  64         ssize_t len;
  65
  66         /*
  67          *      No data allocated.  Read the 4-byte header into
  68          *      a temporary buffer.
  69          */
  70         if (!packet->data) {
  71                 int packet_len;
  72
  73                 len = recv(packet->sockfd, packet->vector + packet->data_len,
  74                            4 - packet->data_len, 0);
  75                 if (len == 0) return -2; /* clean close */
  76
  77 #ifdef ECONNRESET
  78                 if ((len < 0) && (errno == ECONNRESET)) { /* forced */
  79                         return -2;
  80                 }
  81 #endif
  82
  83                 if (len < 0) {
  84                         fr_strerror_printf("Error receiving packet: %s",
  85                                    fr_syserror(errno));
  86                         return -1;
  87                 }
  88
  89                 packet->data_len += len;
  90                 if (packet->data_len < 4) { /* want more data */
  91                         return 0;
  92                 }
  93
  94                 packet_len = (packet->vector[2] << 8) | packet->vector[3];
  95
  96                 if (packet_len < RADIUS_HDR_LEN) {
  97                         fr_strerror_printf("Discarding packet: Smaller than RFC minimum of 20 bytes");
  98                         return -1;
  99                 }
 100
 101                 /*
 102                  *      If the packet is too big, then the socket is bad.
 103                  */
 104                 if (packet_len > MAX_PACKET_LEN) {
 105                         fr_strerror_printf("Discarding packet: Larger than RFC limitation of 4096 bytes");
 106                         return -1;
 107                 }
 108
 109                 packet->data = talloc_array(packet, uint8_t, packet_len);
 110                 if (!packet->data) {
 111                         fr_strerror_printf("Out of memory");
 112                         return -1;
 113                 }
 114
 115                 packet->data_len = packet_len;
 116                 packet->partial = 4;
 117                 memcpy(packet->data, packet->vector, 4);
 118         }
 119
 120         /*
 121          *      Try to read more data.
 122          */
 123         len = recv(packet->sockfd, packet->data + packet->partial,
 124                    packet->data_len - packet->partial, 0);
 125         if (len == 0) return -2; /* clean close */
 126
 127 #ifdef ECONNRESET
 128         if ((len < 0) && (errno == ECONNRESET)) { /* forced */
 129                 return -2;
 130         }
 131 #endif
 132
 133         if (len < 0) {
 134                 fr_strerror_printf("Error receiving packet: %s", fr_syserror(errno));
 135                 return -1;
 136         }
 137
 138         packet->partial += len;
 139
 140         if (packet->partial < packet->data_len) {
 141                 return 0;
 142         }
 143
 144         /*
 145          *      See if it's a well-formed RADIUS packet.
 146          */
 147         if (!rad_packet_ok(packet, flags, NULL)) {
 148                 return -1;
 149         }
 150
 151         /*
 152          *      Explicitly set the VP list to empty.
 153          */
 154         packet->vps = NULL;
 155
 156         if (fr_debug_lvl) {
 157                 char ip_buf[128], buffer[256];
 158
 159                 if (packet->src_ipaddr.af != AF_UNSPEC) {
 160                         inet_ntop(packet->src_ipaddr.af,
 161                                   &packet->src_ipaddr.ipaddr,
 162                                   ip_buf, sizeof(ip_buf));
 163                         snprintf(buffer, sizeof(buffer), "host %s port %d",
 164                                  ip_buf, packet->src_port);
 165                 } else {
 166                         snprintf(buffer, sizeof(buffer), "socket %d",
 167                                  packet->sockfd);
 168                 }
 169
 170
 171                 if (is_radius_code(packet->code)) {
 172                         DEBUG("Received %s packet from %s",
 173                               fr_packet_codes[packet->code], buffer);
 174                 } else {
 175                         DEBUG("Received packet from %s code %d",
 176                               buffer, packet->code);
 177                 }
 178                 DEBUG(", id=%d, length=%zu\n", packet->id, packet->data_len);
 179         }
 180
 181         return 1;               /* done reading the packet */
 182 }
 183
 184 #endif /* WITH_TCP */