1 /* 2 * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD. 3 * Copyright (c) 2016 FUJITSU LIMITED 4 * Copyright (c) 2016 Intel Corporation 5 * 6 * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com> 7 * 8 * This work is licensed under the terms of the GNU GPL, version 2 or 9 * later. See the COPYING file in the top-level directory. 10 */ 11 12 #include "qemu/osdep.h" 13 #include "trace.h" 14 #include "colo.h" 15 #include "net/filter.h" 16 #include "net/net.h" 17 #include "qemu-common.h" 18 #include "qemu/error-report.h" 19 #include "qom/object.h" 20 #include "qemu/main-loop.h" 21 #include "qemu/iov.h" 22 #include "net/checksum.h" 23 #include "net/colo.h" 24 #include "migration/colo.h" 25 26 #define FILTER_COLO_REWRITER(obj) \ 27 OBJECT_CHECK(RewriterState, (obj), TYPE_FILTER_REWRITER) 28 29 #define TYPE_FILTER_REWRITER "filter-rewriter" 30 #define FAILOVER_MODE_ON true 31 #define FAILOVER_MODE_OFF false 32 33 typedef struct RewriterState { 34 NetFilterState parent_obj; 35 NetQueue *incoming_queue; 36 /* hashtable to save connection */ 37 GHashTable *connection_track_table; 38 bool vnet_hdr; 39 bool failover_mode; 40 } RewriterState; 41 42 static void filter_rewriter_failover_mode(RewriterState *s) 43 { 44 s->failover_mode = FAILOVER_MODE_ON; 45 } 46 47 static void filter_rewriter_flush(NetFilterState *nf) 48 { 49 RewriterState *s = FILTER_COLO_REWRITER(nf); 50 51 if (!qemu_net_queue_flush(s->incoming_queue)) { 52 /* Unable to empty the queue, purge remaining packets */ 53 qemu_net_queue_purge(s->incoming_queue, nf->netdev); 54 } 55 } 56 57 /* 58 * Return 1 on success, if return 0 means the pkt 59 * is not TCP packet 60 */ 61 static int is_tcp_packet(Packet *pkt) 62 { 63 if (!parse_packet_early(pkt) && 64 pkt->ip->ip_p == IPPROTO_TCP) { 65 return 1; 66 } else { 67 return 0; 68 } 69 } 70 71 /* handle tcp packet from primary guest */ 72 static int handle_primary_tcp_pkt(RewriterState *rf, 73 Connection *conn, 74 Packet *pkt, ConnectionKey *key) 75 { 76 struct tcphdr *tcp_pkt; 77 78 tcp_pkt = (struct tcphdr *)pkt->transport_header; 79 if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_DEBUG)) { 80 trace_colo_filter_rewriter_pkt_info(__func__, 81 inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst), 82 ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack), 83 tcp_pkt->th_flags); 84 trace_colo_filter_rewriter_conn_offset(conn->offset); 85 } 86 87 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN)) && 88 conn->tcp_state == TCPS_SYN_SENT) { 89 conn->tcp_state = TCPS_ESTABLISHED; 90 } 91 92 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) { 93 /* 94 * we use this flag update offset func 95 * run once in independent tcp connection 96 */ 97 conn->tcp_state = TCPS_SYN_RECEIVED; 98 } 99 100 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK)) { 101 if (conn->tcp_state == TCPS_SYN_RECEIVED) { 102 /* 103 * offset = secondary_seq - primary seq 104 * ack packet sent by guest from primary node, 105 * so we use th_ack - 1 get primary_seq 106 */ 107 conn->offset -= (ntohl(tcp_pkt->th_ack) - 1); 108 conn->tcp_state = TCPS_ESTABLISHED; 109 } 110 if (conn->offset) { 111 /* handle packets to the secondary from the primary */ 112 tcp_pkt->th_ack = htonl(ntohl(tcp_pkt->th_ack) + conn->offset); 113 114 net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len, 115 pkt->size - pkt->vnet_hdr_len); 116 } 117 118 /* 119 * Passive close step 3 120 */ 121 if ((conn->tcp_state == TCPS_LAST_ACK) && 122 (ntohl(tcp_pkt->th_ack) == (conn->fin_ack_seq + 1))) { 123 conn->tcp_state = TCPS_CLOSED; 124 g_hash_table_remove(rf->connection_track_table, key); 125 } 126 } 127 128 if ((tcp_pkt->th_flags & TH_FIN) == TH_FIN) { 129 /* 130 * Passive close. 131 * Step 1: 132 * The *server* side of this connect is VM, *client* tries to close 133 * the connection. We will into CLOSE_WAIT status. 134 * 135 * Step 2: 136 * In this step we will into LAST_ACK status. 137 * 138 * We got 'fin=1, ack=1' packet from server side, we need to 139 * record the seq of 'fin=1, ack=1' packet. 140 * 141 * Step 3: 142 * We got 'ack=1' packets from client side, it acks 'fin=1, ack=1' 143 * packet from server side. From this point, we can ensure that there 144 * will be no packets in the connection, except that, some errors 145 * happen between the path of 'filter object' and vNIC, if this rare 146 * case really happen, we can still create a new connection, 147 * So it is safe to remove the connection from connection_track_table. 148 * 149 */ 150 if (conn->tcp_state == TCPS_ESTABLISHED) { 151 conn->tcp_state = TCPS_CLOSE_WAIT; 152 } 153 154 /* 155 * Active close step 2. 156 */ 157 if (conn->tcp_state == TCPS_FIN_WAIT_1) { 158 conn->tcp_state = TCPS_TIME_WAIT; 159 /* 160 * For simplify implementation, we needn't wait 2MSL time 161 * in filter rewriter. Because guest kernel will track the 162 * TCP status and wait 2MSL time, if client resend the FIN 163 * packet, guest will apply the last ACK too. 164 */ 165 conn->tcp_state = TCPS_CLOSED; 166 g_hash_table_remove(rf->connection_track_table, key); 167 } 168 } 169 170 return 0; 171 } 172 173 /* handle tcp packet from secondary guest */ 174 static int handle_secondary_tcp_pkt(RewriterState *rf, 175 Connection *conn, 176 Packet *pkt, ConnectionKey *key) 177 { 178 struct tcphdr *tcp_pkt; 179 180 tcp_pkt = (struct tcphdr *)pkt->transport_header; 181 182 if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_DEBUG)) { 183 trace_colo_filter_rewriter_pkt_info(__func__, 184 inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst), 185 ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack), 186 tcp_pkt->th_flags); 187 trace_colo_filter_rewriter_conn_offset(conn->offset); 188 } 189 190 if (conn->tcp_state == TCPS_SYN_RECEIVED && 191 ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) { 192 /* 193 * save offset = secondary_seq and then 194 * in handle_primary_tcp_pkt make offset 195 * = secondary_seq - primary_seq 196 */ 197 conn->offset = ntohl(tcp_pkt->th_seq); 198 } 199 200 /* VM active connect */ 201 if (conn->tcp_state == TCPS_CLOSED && 202 ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) { 203 conn->tcp_state = TCPS_SYN_SENT; 204 } 205 206 if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK) { 207 /* Only need to adjust seq while offset is Non-zero */ 208 if (conn->offset) { 209 /* handle packets to the primary from the secondary*/ 210 tcp_pkt->th_seq = htonl(ntohl(tcp_pkt->th_seq) - conn->offset); 211 212 net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len, 213 pkt->size - pkt->vnet_hdr_len); 214 } 215 } 216 217 /* 218 * Passive close step 2: 219 */ 220 if (conn->tcp_state == TCPS_CLOSE_WAIT && 221 (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == (TH_ACK | TH_FIN)) { 222 conn->fin_ack_seq = ntohl(tcp_pkt->th_seq); 223 conn->tcp_state = TCPS_LAST_ACK; 224 } 225 226 /* 227 * Active close 228 * 229 * Step 1: 230 * The *server* side of this connect is VM, *server* tries to close 231 * the connection. 232 * 233 * Step 2: 234 * We will into CLOSE_WAIT status. 235 * We simplify the TCPS_FIN_WAIT_2, TCPS_TIME_WAIT and 236 * CLOSING status. 237 */ 238 if (conn->tcp_state == TCPS_ESTABLISHED && 239 (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == TH_FIN) { 240 conn->tcp_state = TCPS_FIN_WAIT_1; 241 } 242 243 return 0; 244 } 245 246 static ssize_t colo_rewriter_receive_iov(NetFilterState *nf, 247 NetClientState *sender, 248 unsigned flags, 249 const struct iovec *iov, 250 int iovcnt, 251 NetPacketSent *sent_cb) 252 { 253 RewriterState *s = FILTER_COLO_REWRITER(nf); 254 Connection *conn; 255 ConnectionKey key; 256 Packet *pkt; 257 ssize_t size = iov_size(iov, iovcnt); 258 ssize_t vnet_hdr_len = 0; 259 char *buf = g_malloc0(size); 260 261 iov_to_buf(iov, iovcnt, 0, buf, size); 262 263 if (s->vnet_hdr) { 264 vnet_hdr_len = nf->netdev->vnet_hdr_len; 265 } 266 267 pkt = packet_new(buf, size, vnet_hdr_len); 268 g_free(buf); 269 270 /* 271 * if we get tcp packet 272 * we will rewrite it to make secondary guest's 273 * connection established successfully 274 */ 275 if (pkt && is_tcp_packet(pkt)) { 276 277 fill_connection_key(pkt, &key); 278 279 if (sender == nf->netdev) { 280 /* 281 * We need make tcp TX and RX packet 282 * into one connection. 283 */ 284 reverse_connection_key(&key); 285 } 286 287 /* After failover we needn't change new TCP packet */ 288 if (s->failover_mode && 289 !connection_has_tracked(s->connection_track_table, &key)) { 290 goto out; 291 } 292 293 conn = connection_get(s->connection_track_table, 294 &key, 295 NULL); 296 297 if (sender == nf->netdev) { 298 /* NET_FILTER_DIRECTION_TX */ 299 if (!handle_primary_tcp_pkt(s, conn, pkt, &key)) { 300 qemu_net_queue_send(s->incoming_queue, sender, 0, 301 (const uint8_t *)pkt->data, pkt->size, NULL); 302 packet_destroy(pkt, NULL); 303 pkt = NULL; 304 /* 305 * We block the packet here,after rewrite pkt 306 * and will send it 307 */ 308 return 1; 309 } 310 } else { 311 /* NET_FILTER_DIRECTION_RX */ 312 if (!handle_secondary_tcp_pkt(s, conn, pkt, &key)) { 313 qemu_net_queue_send(s->incoming_queue, sender, 0, 314 (const uint8_t *)pkt->data, pkt->size, NULL); 315 packet_destroy(pkt, NULL); 316 pkt = NULL; 317 /* 318 * We block the packet here,after rewrite pkt 319 * and will send it 320 */ 321 return 1; 322 } 323 } 324 } 325 326 out: 327 packet_destroy(pkt, NULL); 328 pkt = NULL; 329 return 0; 330 } 331 332 static void reset_seq_offset(gpointer key, gpointer value, gpointer user_data) 333 { 334 Connection *conn = (Connection *)value; 335 336 conn->offset = 0; 337 } 338 339 static gboolean offset_is_nonzero(gpointer key, 340 gpointer value, 341 gpointer user_data) 342 { 343 Connection *conn = (Connection *)value; 344 345 return conn->offset ? true : false; 346 } 347 348 static void colo_rewriter_handle_event(NetFilterState *nf, int event, 349 Error **errp) 350 { 351 RewriterState *rs = FILTER_COLO_REWRITER(nf); 352 353 switch (event) { 354 case COLO_EVENT_CHECKPOINT: 355 g_hash_table_foreach(rs->connection_track_table, 356 reset_seq_offset, NULL); 357 break; 358 case COLO_EVENT_FAILOVER: 359 if (!g_hash_table_find(rs->connection_track_table, 360 offset_is_nonzero, NULL)) { 361 filter_rewriter_failover_mode(rs); 362 } 363 break; 364 default: 365 break; 366 } 367 } 368 369 static void colo_rewriter_cleanup(NetFilterState *nf) 370 { 371 RewriterState *s = FILTER_COLO_REWRITER(nf); 372 373 /* flush packets */ 374 if (s->incoming_queue) { 375 filter_rewriter_flush(nf); 376 g_free(s->incoming_queue); 377 } 378 } 379 380 static void colo_rewriter_setup(NetFilterState *nf, Error **errp) 381 { 382 RewriterState *s = FILTER_COLO_REWRITER(nf); 383 384 s->connection_track_table = g_hash_table_new_full(connection_key_hash, 385 connection_key_equal, 386 g_free, 387 connection_destroy); 388 s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf); 389 } 390 391 static bool filter_rewriter_get_vnet_hdr(Object *obj, Error **errp) 392 { 393 RewriterState *s = FILTER_COLO_REWRITER(obj); 394 395 return s->vnet_hdr; 396 } 397 398 static void filter_rewriter_set_vnet_hdr(Object *obj, 399 bool value, 400 Error **errp) 401 { 402 RewriterState *s = FILTER_COLO_REWRITER(obj); 403 404 s->vnet_hdr = value; 405 } 406 407 static void filter_rewriter_init(Object *obj) 408 { 409 RewriterState *s = FILTER_COLO_REWRITER(obj); 410 411 s->vnet_hdr = false; 412 s->failover_mode = FAILOVER_MODE_OFF; 413 object_property_add_bool(obj, "vnet_hdr_support", 414 filter_rewriter_get_vnet_hdr, 415 filter_rewriter_set_vnet_hdr, NULL); 416 } 417 418 static void colo_rewriter_class_init(ObjectClass *oc, void *data) 419 { 420 NetFilterClass *nfc = NETFILTER_CLASS(oc); 421 422 nfc->setup = colo_rewriter_setup; 423 nfc->cleanup = colo_rewriter_cleanup; 424 nfc->receive_iov = colo_rewriter_receive_iov; 425 nfc->handle_event = colo_rewriter_handle_event; 426 } 427 428 static const TypeInfo colo_rewriter_info = { 429 .name = TYPE_FILTER_REWRITER, 430 .parent = TYPE_NETFILTER, 431 .class_init = colo_rewriter_class_init, 432 .instance_init = filter_rewriter_init, 433 .instance_size = sizeof(RewriterState), 434 }; 435 436 static void register_types(void) 437 { 438 type_register_static(&colo_rewriter_info); 439 } 440 441 type_init(register_types); 442