ctdb/tools/ctdb_killtcp.c

   1 /*
   2    CTDB TCP connection killing utility
   3
   4    Copyright (C) Martin Schwenke <martin@meltin.net> 2016
   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 #include "replace.h"
  21 #include "system/network.h"
  22
  23 #include <talloc.h>
  24 #include <tevent.h>
  25
  26 #include "lib/util/debug.h"
  27 #include "lib/util/tevent_unix.h"
  28
  29 #include "protocol/protocol.h"
  30 #include "protocol/protocol_util.h"
  31
  32 #include "common/db_hash.h"
  33 #include "common/system_socket.h"
  34 #include "common/logging.h"
  35
  36
  37 struct reset_connections_state {
  38         struct tevent_context *ev;
  39         int capture_fd;
  40         struct tevent_fd *fde;
  41         struct db_hash_context *connections;
  42         void *private_data;
  43         unsigned int attempts;
  44         unsigned int max_attempts;
  45         struct timeval retry_interval;
  46         unsigned int batch_count;
  47         unsigned int batch_size;
  48 };
  49
  50
  51 static void reset_connections_capture_tcp_handler(struct tevent_context *ev,
  52                                                   struct tevent_fd *fde,
  53                                                   uint16_t flags,
  54                                                   void *private_data);
  55 static void reset_connections_batch(struct tevent_req *subreq);
  56 static int reset_connections_tickle_connection(
  57                                         uint8_t *keybuf, size_t keylen,
  58                                         uint8_t *databuf, size_t datalen,
  59                                         void *private_data);
  60
  61 static struct tevent_req *reset_connections_send(
  62                               TALLOC_CTX *mem_ctx,
  63                               struct tevent_context *ev,
  64                               const char *iface,
  65                               struct ctdb_connection_list *conn_list)
  66 {
  67         struct tevent_req *req, *subreq;
  68         struct reset_connections_state *state;
  69         unsigned int i;
  70         int ret;
  71
  72         req = tevent_req_create(mem_ctx, &state,
  73                                 struct reset_connections_state);
  74         if (req == NULL) {
  75                 return NULL;
  76         }
  77
  78         state->ev = ev;
  79
  80         if (conn_list->num == 0) {
  81                 /* No connections, done! */
  82                 tevent_req_done(req);
  83                 return tevent_req_post(req, ev);
  84         }
  85
  86         ret = db_hash_init(state, "connections", 2048, DB_HASH_SIMPLE,
  87                            &state->connections);
  88         if (ret != 0) {
  89                 D_ERR("Failed to initialise connection hash (%s)\n",
  90                       strerror(ret));
  91                 tevent_req_error(req, ret);
  92                 return tevent_req_post(req, ev);
  93         }
  94
  95         DBG_DEBUG("Adding %u connections to hash\n", conn_list->num);
  96         for (i = 0; i < conn_list->num; i++) {
  97                 struct ctdb_connection *c = &conn_list->conn[i];
  98
  99                 DBG_DEBUG("Adding connection to hash: %s\n",
 100                           ctdb_connection_to_string(conn_list, c, true));
 101
 102                 /* Connection is stored as a key in the connections hash */
 103                 ret = db_hash_add(state->connections,
 104                                   (uint8_t *)discard_const(c), sizeof(*c),
 105                                   NULL, 0);
 106                 if (ret != 0) {
 107                         D_ERR("Error adding connection to hash (%s)\n",
 108                               strerror(ret));
 109                         tevent_req_error(req, ret);
 110                         return tevent_req_post(req, ev);
 111                 }
 112         }
 113
 114         state->attempts = 0;
 115         state->max_attempts = 50;
 116
 117         state->retry_interval.tv_sec = 0;
 118         state->retry_interval.tv_usec = 100 * 1000;
 119
 120         state->batch_count = 0;
 121         state->batch_size = 300;
 122
 123         state->capture_fd =
 124                 ctdb_sys_open_capture_socket(iface, &state->private_data);
 125         if (state->capture_fd == -1) {
 126                 D_ERR("Failed to open capture socket on iface '%s' (%s)\n",
 127                       iface, strerror(errno));
 128                         tevent_req_error(req, EIO);
 129                         return tevent_req_post(req, ev);
 130         }
 131
 132         state->fde = tevent_add_fd(ev, state, state->capture_fd,
 133                                    TEVENT_FD_READ,
 134                                    reset_connections_capture_tcp_handler,
 135                                    state);
 136         if (tevent_req_nomem(state->fde, req)) {
 137                 return tevent_req_post(req, ev);
 138         }
 139         tevent_fd_set_auto_close(state->fde);
 140
 141         subreq = tevent_wakeup_send(state, ev, tevent_timeval_current_ofs(0,0));
 142         if (tevent_req_nomem(subreq, req)) {
 143                 return tevent_req_post(req, ev);
 144         }
 145         tevent_req_set_callback(subreq, reset_connections_batch, req);
 146
 147         return req;
 148 }
 149
 150 /*
 151   called when we get a read event on the raw socket
 152  */
 153 static void reset_connections_capture_tcp_handler(struct tevent_context *ev,
 154                                                   struct tevent_fd *fde,
 155                                                   uint16_t flags,
 156                                                   void *private_data)
 157 {
 158         struct reset_connections_state *state = talloc_get_type_abort(
 159                 private_data, struct reset_connections_state);
 160         /* 0 the parts that don't get set by ctdb_sys_read_tcp_packet */
 161         struct ctdb_connection conn;
 162         uint32_t ack_seq, seq;
 163         int rst;
 164         uint16_t window;
 165         int ret;
 166
 167         ret = ctdb_sys_read_tcp_packet(state->capture_fd,
 168                                        state->private_data,
 169                                        &conn.server, &conn.client,
 170                                        &ack_seq, &seq, &rst, &window);
 171         if (ret != 0) {
 172                 /* Not a TCP-ACK?  Unexpected protocol? */
 173                 DBG_DEBUG("Failed to parse packet, errno=%d\n", ret);
 174                 return;
 175         }
 176
 177         if (window == htons(1234) && (rst || seq == 0)) {
 178                 /* Ignore packets that we sent! */
 179                 DBG_DEBUG("Ignoring sent packet: %s, "
 180                           "seq=%"PRIu32", ack_seq=%"PRIu32", "
 181                           "rst=%d, window=%"PRIu16"\n",
 182                           ctdb_connection_to_string(state, &conn, false),
 183                           seq, ack_seq, rst, ntohs(window));
 184                 return;
 185         }
 186
 187         /* Check if this connection is one being reset, if found then delete */
 188         ret = db_hash_delete(state->connections,
 189                              (uint8_t*)&conn, sizeof(conn));
 190         if (ret == ENOENT) {
 191                 /* Packet for some other connection, ignore */
 192                 DBG_DEBUG("Ignoring packet for unknown connection: %s\n",
 193                           ctdb_connection_to_string(state, &conn, true));
 194                 return;
 195         }
 196         if (ret != 0) {
 197                 DBG_WARNING("Internal error (%s)\n", strerror(ret));
 198                 return;
 199         }
 200
 201         D_INFO("Sending a TCP RST to for connection %s\n",
 202                ctdb_connection_to_string(state, &conn, true));
 203
 204         ret = ctdb_sys_send_tcp(&conn.server, &conn.client, ack_seq, seq, 1);
 205         if (ret != 0) {
 206                 DBG_ERR("Error sending TCP RST for connection\n");
 207         }
 208 }
 209
 210 /*
 211  * Called periodically until all sentenced connections have been reset
 212  * or enough attempts have been made
 213  */
 214 static void reset_connections_batch(struct tevent_req *subreq)
 215 {
 216         struct tevent_req *req = tevent_req_callback_data(
 217                 subreq, struct tevent_req);
 218         struct reset_connections_state *state = tevent_req_data(
 219                 req, struct reset_connections_state);
 220         bool status;
 221         int count, ret;
 222
 223         status = tevent_wakeup_recv(subreq);
 224         TALLOC_FREE(subreq);
 225
 226         if (! status) {
 227                 DBG_WARNING("Unexpected error on timer expiry\n");
 228                 /* Keep going... */
 229         }
 230
 231         /* loop over up to batch_size connections sending tickle ACKs */
 232         state->batch_count = 0;
 233         ret = db_hash_traverse(state->connections,
 234                                reset_connections_tickle_connection,
 235                                state, NULL);
 236         if (ret != 0) {
 237                 DBG_WARNING("Unexpected error traversing connections (%s)\n",
 238                             strerror(ret));
 239         }
 240
 241         state->attempts++;
 242
 243         /*
 244          * If there are no more connections to kill or we have tried
 245          * too many times we're finished
 246          */
 247         ret = db_hash_traverse(state->connections, NULL, NULL, &count);
 248         if (ret != 0) {
 249                 /* What now?  Try again until max_attempts reached */
 250                 DBG_WARNING("Unexpected error traversing connections (%s)\n",
 251                             strerror(ret));
 252                 count = 1;
 253         }
 254         if (count == 0 ||
 255             state->attempts >= state->max_attempts) {
 256                 tevent_req_done(req);
 257                 return;
 258         }
 259
 260         /* Schedule next attempt */
 261         subreq = tevent_wakeup_send(state, state->ev,
 262                                     tevent_timeval_current_ofs(
 263                                             state->retry_interval.tv_sec,
 264                                             state->retry_interval.tv_usec));
 265         if (tevent_req_nomem(subreq, req)) {
 266                 return;
 267         }
 268         tevent_req_set_callback(subreq, reset_connections_batch, req);
 269 }
 270
 271 static int reset_connections_tickle_connection(
 272                                         uint8_t *keybuf, size_t keylen,
 273                                         uint8_t *databuf, size_t datalen,
 274                                         void *private_data)
 275 {
 276         struct reset_connections_state *state = talloc_get_type_abort(
 277                 private_data, struct reset_connections_state);
 278         struct ctdb_connection *conn;
 279         int ret;
 280
 281         if (keylen != sizeof(*conn)) {
 282                 DBG_WARNING("Unexpected data in connection hash\n");
 283                 return 0;
 284         }
 285
 286         conn = (struct ctdb_connection *)keybuf;
 287
 288         state->batch_count++;
 289         if (state->batch_count > state->batch_size) {
 290                 /* Terminate the traverse */
 291                 return 1;
 292         }
 293
 294         DBG_DEBUG("Sending tickle ACK for connection '%s'\n",
 295                   ctdb_connection_to_string(state, conn, true));
 296         ret = ctdb_sys_send_tcp(&conn->server, &conn->client, 0, 0, 0);
 297         if (ret != 0) {
 298                 DBG_ERR("Error sending tickle ACK\n");
 299                 /* continue */
 300         }
 301
 302         return 0;
 303 }
 304
 305 static bool reset_connections_recv(struct tevent_req *req, int *perr)
 306 {
 307         int err;
 308
 309         if (tevent_req_is_unix_error(req, &err)) {
 310                 if (perr != NULL) {
 311                         *perr = err;
 312                 }
 313                 return false;
 314         }
 315
 316         return true;
 317 }
 318
 319 static void usage(const char *prog)
 320 {
 321         printf("usage: %s <interface> [ <srcip:port> <dstip:port> ]\n", prog);
 322         exit(1);
 323 }
 324
 325 int main(int argc, char **argv)
 326 {
 327         struct ctdb_connection conn;
 328         struct tevent_context *ev = NULL;
 329         TALLOC_CTX *mem_ctx = NULL;
 330         struct ctdb_connection_list *conn_list = NULL;
 331         const char *t;
 332         struct tevent_req *req;
 333         int debug_level;
 334         bool status;
 335         bool ok;
 336         int ret;
 337
 338         /* Set the debug level */
 339         t = getenv("CTDB_DEBUGLEVEL");
 340         if (t != NULL) {
 341                 ok = debug_level_parse(t, &debug_level);
 342                 if (!ok) {
 343                         debug_level = DEBUG_ERR;
 344                 }
 345                 debuglevel_set(debug_level);
 346         }
 347
 348         if (argc != 2 && argc != 4) {
 349                 usage(argv[0]);
 350         }
 351
 352         if (argc == 4) {
 353                 ret = ctdb_sock_addr_from_string(argv[2], &conn.client, true);
 354                 if (ret != 0) {
 355                         D_ERR("Bad IP:port '%s'\n", argv[2]);
 356                         goto fail;
 357                 }
 358
 359                 ret = ctdb_sock_addr_from_string(argv[3], &conn.server, true);
 360                 if (ret != 0) {
 361                         D_ERR("Bad IP:port '%s'\n", argv[3]);
 362                         goto fail;
 363                 }
 364
 365
 366                 conn_list = talloc_zero(mem_ctx, struct ctdb_connection_list);
 367                 if (conn_list == NULL) {
 368                         ret = ENOMEM;
 369                         DBG_ERR("Internal error (%s)\n", strerror(ret));
 370                         goto fail;
 371                 }
 372                 ret = ctdb_connection_list_add(conn_list, &conn);
 373                 if (ret != 0) {
 374                         DBG_ERR("Internal error (%s)\n", strerror(ret));
 375                         goto fail;
 376                 }
 377         } else {
 378                 ret = ctdb_connection_list_read(mem_ctx, 0, true, &conn_list);
 379                 if (ret != 0) {
 380                         D_ERR("Unable to parse connections (%s)\n",
 381                               strerror(ret));
 382                         goto fail;
 383                 }
 384         }
 385
 386         mem_ctx = talloc_new(NULL);
 387         if (mem_ctx == NULL) {
 388                 DEBUG(DEBUG_ERR, (__location__ " out of memory\n"));
 389                 goto fail;
 390         }
 391
 392         ev = tevent_context_init(mem_ctx);
 393         if (ev == NULL) {
 394                 DEBUG(DEBUG_ERR, ("Failed to initialise tevent\n"));
 395                 goto fail;
 396         }
 397
 398         req = reset_connections_send(mem_ctx, ev, argv[1], conn_list);
 399         if (req == NULL) {
 400                 goto fail;
 401         }
 402
 403         tevent_req_poll(req, ev);
 404
 405         status = reset_connections_recv(req, &ret);
 406         if (! status) {
 407                 D_ERR("Failed to kill connections (%s)\n", strerror(ret));
 408                 goto fail;
 409         }
 410
 411         talloc_free(mem_ctx);
 412
 413         return 0;
 414
 415 fail:
 416         TALLOC_FREE(mem_ctx);
 417         return -1;
 418 }