source3/libsmb/unexpected.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    handle unexpected packets
   4    Copyright (C) Andrew Tridgell 2000
   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 3 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, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 #include "includes.h"
  22
  23 static struct tdb_wrap *tdbd = NULL;
  24
  25 /* the key type used in the unexpected packet database */
  26 struct unexpected_key {
  27         enum packet_type packet_type;
  28         time_t timestamp;
  29         int count;
  30 };
  31
  32 /****************************************************************************
  33  All unexpected packets are passed in here, to be stored in a unexpected
  34  packet database. This allows nmblookup and other tools to receive packets
  35  erroneously sent to the wrong port by broken MS systems.
  36 **************************************************************************/
  37
  38 void unexpected_packet(struct packet_struct *p)
  39 {
  40         static int count;
  41         TDB_DATA kbuf, dbuf;
  42         struct unexpected_key key;
  43         char buf[1024];
  44         int len=0;
  45         uint32_t enc_ip;
  46
  47         if (!tdbd) {
  48                 tdbd = tdb_wrap_open(talloc_autofree_context(),
  49                                      lock_path("unexpected.tdb"), 0,
  50                                      TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
  51                                      O_RDWR | O_CREAT, 0644);
  52                 if (!tdbd) {
  53                         DEBUG(0,("Failed to open unexpected.tdb\n"));
  54                         return;
  55                 }
  56         }
  57
  58         memset(buf,'\0',sizeof(buf));
  59
  60         /* Encode the ip addr and port. */
  61         enc_ip = ntohl(p->ip.s_addr);
  62         SIVAL(buf,0,enc_ip);
  63         SSVAL(buf,4,p->port);
  64
  65         len = build_packet(&buf[6], sizeof(buf)-6, p) + 6;
  66
  67         ZERO_STRUCT(key);       /* needed for potential alignment */
  68
  69         key.packet_type = p->packet_type;
  70         key.timestamp = p->timestamp;
  71         key.count = count++;
  72
  73         kbuf.dptr = (uint8_t *)&key;
  74         kbuf.dsize = sizeof(key);
  75         dbuf.dptr = (uint8_t *)buf;
  76         dbuf.dsize = len;
  77
  78         tdb_store(tdbd->tdb, kbuf, dbuf, TDB_REPLACE);
  79 }
  80
  81
  82 static time_t lastt;
  83
  84 /****************************************************************************
  85  Delete the record if it is too old.
  86 **************************************************************************/
  87
  88 static int traverse_fn(TDB_CONTEXT *ttdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
  89 {
  90         struct unexpected_key key;
  91
  92         if (kbuf.dsize != sizeof(key)) {
  93                 tdb_delete(ttdb, kbuf);
  94         }
  95
  96         memcpy(&key, kbuf.dptr, sizeof(key));
  97
  98         if (lastt - key.timestamp > NMBD_UNEXPECTED_TIMEOUT) {
  99                 tdb_delete(ttdb, kbuf);
 100         }
 101
 102         return 0;
 103 }
 104
 105
 106 /****************************************************************************
 107  Delete all old unexpected packets.
 108 **************************************************************************/
 109
 110 void clear_unexpected(time_t t)
 111 {
 112         if (!tdbd) return;
 113
 114         if ((lastt != 0) && (t < lastt + NMBD_UNEXPECTED_TIMEOUT))
 115                 return;
 116
 117         lastt = t;
 118
 119         tdb_traverse(tdbd->tdb, traverse_fn, NULL);
 120 }
 121
 122 struct receive_unexpected_state {
 123         struct packet_struct *matched_packet;
 124         int match_id;
 125         enum packet_type match_type;
 126         const char *match_name;
 127 };
 128
 129 /****************************************************************************
 130  tdb traversal fn to find a matching 137 packet.
 131 **************************************************************************/
 132
 133 static int traverse_match(TDB_CONTEXT *ttdb, TDB_DATA kbuf, TDB_DATA dbuf,
 134                           void *private_data)
 135 {
 136         struct receive_unexpected_state *state =
 137                 (struct receive_unexpected_state *)private_data;
 138         struct unexpected_key key;
 139         struct in_addr ip;
 140         uint32_t enc_ip;
 141         int port;
 142         struct packet_struct *p;
 143
 144         if (kbuf.dsize != sizeof(key)) {
 145                 return 0;
 146         }
 147
 148         memcpy(&key, kbuf.dptr, sizeof(key));
 149
 150         if (key.packet_type != state->match_type) return 0;
 151
 152         if (dbuf.dsize < 6) {
 153                 return 0;
 154         }
 155
 156         /* Decode the ip addr and port. */
 157         enc_ip = IVAL(dbuf.dptr,0);
 158         ip.s_addr = htonl(enc_ip);
 159         port = SVAL(dbuf.dptr,4);
 160
 161         p = parse_packet((char *)&dbuf.dptr[6],
 162                         dbuf.dsize-6,
 163                         state->match_type,
 164                         ip,
 165                         port);
 166         if (!p)
 167                 return 0;
 168
 169         if ((state->match_type == NMB_PACKET &&
 170              p->packet.nmb.header.name_trn_id == state->match_id) ||
 171             (state->match_type == DGRAM_PACKET &&
 172              match_mailslot_name(p, state->match_name))) {
 173                 state->matched_packet = p;
 174                 return -1;
 175         }
 176
 177         free_packet(p);
 178
 179         return 0;
 180 }
 181
 182 /****************************************************************************
 183  Check for a particular packet in the unexpected packet queue.
 184 **************************************************************************/
 185
 186 struct packet_struct *receive_unexpected(enum packet_type packet_type, int id,
 187                                          const char *mailslot_name)
 188 {
 189         struct tdb_wrap *tdb2;
 190         struct receive_unexpected_state state;
 191
 192         tdb2 = tdb_wrap_open(talloc_autofree_context(),
 193                              lock_path("unexpected.tdb"), 0, 0, O_RDONLY, 0);
 194         if (!tdb2) return NULL;
 195
 196         state.matched_packet = NULL;
 197         state.match_id = id;
 198         state.match_type = packet_type;
 199         state.match_name = mailslot_name;
 200
 201         tdb_traverse(tdb2->tdb, traverse_match, &state);
 202
 203         TALLOC_FREE(tdb2);
 204
 205         return state.matched_packet;
 206 }