Merge remote-tracking branch 'remotes/kraxel/tags/input-20200921-pull-request' into...
[qemu.git] / net / filter-rewriter.c
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/error-report.h"
18 #include "qom/object.h"
19 #include "qemu/main-loop.h"
20 #include "qemu/iov.h"
21 #include "net/checksum.h"
22 #include "net/colo.h"
23 #include "migration/colo.h"
24 #include "util.h"
25
26 #define TYPE_FILTER_REWRITER "filter-rewriter"
27 OBJECT_DECLARE_SIMPLE_TYPE(RewriterState, FILTER_REWRITER)
28
29 #define FAILOVER_MODE_ON true
30 #define FAILOVER_MODE_OFF false
31
32 struct RewriterState {
33 NetFilterState parent_obj;
34 NetQueue *incoming_queue;
35 /* hashtable to save connection */
36 GHashTable *connection_track_table;
37 bool vnet_hdr;
38 bool failover_mode;
39 };
40
41 static void filter_rewriter_failover_mode(RewriterState *s)
42 {
43 s->failover_mode = FAILOVER_MODE_ON;
44 }
45
46 static void filter_rewriter_flush(NetFilterState *nf)
47 {
48 RewriterState *s = FILTER_REWRITER(nf);
49
50 if (!qemu_net_queue_flush(s->incoming_queue)) {
51 /* Unable to empty the queue, purge remaining packets */
52 qemu_net_queue_purge(s->incoming_queue, nf->netdev);
53 }
54 }
55
56 /*
57 * Return 1 on success, if return 0 means the pkt
58 * is not TCP packet
59 */
60 static int is_tcp_packet(Packet *pkt)
61 {
62 if (!parse_packet_early(pkt) &&
63 pkt->ip->ip_p == IPPROTO_TCP) {
64 return 1;
65 } else {
66 return 0;
67 }
68 }
69
70 /* handle tcp packet from primary guest */
71 static int handle_primary_tcp_pkt(RewriterState *rf,
72 Connection *conn,
73 Packet *pkt, ConnectionKey *key)
74 {
75 struct tcp_hdr *tcp_pkt;
76
77 tcp_pkt = (struct tcp_hdr *)pkt->transport_header;
78 if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_PKT_INFO)) {
79 trace_colo_filter_rewriter_pkt_info(__func__,
80 inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
81 ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
82 tcp_pkt->th_flags);
83 }
84 if (trace_event_get_state_backends(
85 TRACE_COLO_FILTER_REWRITER_CONN_OFFSET)) {
86 trace_colo_filter_rewriter_conn_offset(conn->offset);
87 }
88
89 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN)) &&
90 conn->tcp_state == TCPS_SYN_SENT) {
91 conn->tcp_state = TCPS_ESTABLISHED;
92 }
93
94 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) {
95 /*
96 * we use this flag update offset func
97 * run once in independent tcp connection
98 */
99 conn->tcp_state = TCPS_SYN_RECEIVED;
100 }
101
102 if (((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK)) {
103 if (conn->tcp_state == TCPS_SYN_RECEIVED) {
104 /*
105 * offset = secondary_seq - primary seq
106 * ack packet sent by guest from primary node,
107 * so we use th_ack - 1 get primary_seq
108 */
109 conn->offset -= (ntohl(tcp_pkt->th_ack) - 1);
110 conn->tcp_state = TCPS_ESTABLISHED;
111 }
112 if (conn->offset) {
113 /* handle packets to the secondary from the primary */
114 tcp_pkt->th_ack = htonl(ntohl(tcp_pkt->th_ack) + conn->offset);
115
116 net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
117 pkt->size - pkt->vnet_hdr_len);
118 }
119
120 /*
121 * Passive close step 3
122 */
123 if ((conn->tcp_state == TCPS_LAST_ACK) &&
124 (ntohl(tcp_pkt->th_ack) == (conn->fin_ack_seq + 1))) {
125 conn->tcp_state = TCPS_CLOSED;
126 g_hash_table_remove(rf->connection_track_table, key);
127 }
128 }
129
130 if ((tcp_pkt->th_flags & TH_FIN) == TH_FIN) {
131 /*
132 * Passive close.
133 * Step 1:
134 * The *server* side of this connect is VM, *client* tries to close
135 * the connection. We will into CLOSE_WAIT status.
136 *
137 * Step 2:
138 * In this step we will into LAST_ACK status.
139 *
140 * We got 'fin=1, ack=1' packet from server side, we need to
141 * record the seq of 'fin=1, ack=1' packet.
142 *
143 * Step 3:
144 * We got 'ack=1' packets from client side, it acks 'fin=1, ack=1'
145 * packet from server side. From this point, we can ensure that there
146 * will be no packets in the connection, except that, some errors
147 * happen between the path of 'filter object' and vNIC, if this rare
148 * case really happen, we can still create a new connection,
149 * So it is safe to remove the connection from connection_track_table.
150 *
151 */
152 if (conn->tcp_state == TCPS_ESTABLISHED) {
153 conn->tcp_state = TCPS_CLOSE_WAIT;
154 }
155
156 /*
157 * Active close step 2.
158 */
159 if (conn->tcp_state == TCPS_FIN_WAIT_1) {
160 /*
161 * For simplify implementation, we needn't wait 2MSL time
162 * in filter rewriter. Because guest kernel will track the
163 * TCP status and wait 2MSL time, if client resend the FIN
164 * packet, guest will apply the last ACK too.
165 * So, we skip the TCPS_TIME_WAIT state here and go straight
166 * to TCPS_CLOSED state.
167 */
168 conn->tcp_state = TCPS_CLOSED;
169 g_hash_table_remove(rf->connection_track_table, key);
170 }
171 }
172
173 return 0;
174 }
175
176 /* handle tcp packet from secondary guest */
177 static int handle_secondary_tcp_pkt(RewriterState *rf,
178 Connection *conn,
179 Packet *pkt, ConnectionKey *key)
180 {
181 struct tcp_hdr *tcp_pkt;
182
183 tcp_pkt = (struct tcp_hdr *)pkt->transport_header;
184
185 if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_PKT_INFO)) {
186 trace_colo_filter_rewriter_pkt_info(__func__,
187 inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
188 ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
189 tcp_pkt->th_flags);
190 }
191 if (trace_event_get_state_backends(
192 TRACE_COLO_FILTER_REWRITER_CONN_OFFSET)) {
193 trace_colo_filter_rewriter_conn_offset(conn->offset);
194 }
195
196 if (conn->tcp_state == TCPS_SYN_RECEIVED &&
197 ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == (TH_ACK | TH_SYN))) {
198 /*
199 * save offset = secondary_seq and then
200 * in handle_primary_tcp_pkt make offset
201 * = secondary_seq - primary_seq
202 */
203 conn->offset = ntohl(tcp_pkt->th_seq);
204 }
205
206 /* VM active connect */
207 if (conn->tcp_state == TCPS_CLOSED &&
208 ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_SYN)) {
209 conn->tcp_state = TCPS_SYN_SENT;
210 }
211
212 if ((tcp_pkt->th_flags & (TH_ACK | TH_SYN)) == TH_ACK) {
213 /* Only need to adjust seq while offset is Non-zero */
214 if (conn->offset) {
215 /* handle packets to the primary from the secondary*/
216 tcp_pkt->th_seq = htonl(ntohl(tcp_pkt->th_seq) - conn->offset);
217
218 net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
219 pkt->size - pkt->vnet_hdr_len);
220 }
221 }
222
223 /*
224 * Passive close step 2:
225 */
226 if (conn->tcp_state == TCPS_CLOSE_WAIT &&
227 (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == (TH_ACK | TH_FIN)) {
228 conn->fin_ack_seq = ntohl(tcp_pkt->th_seq);
229 conn->tcp_state = TCPS_LAST_ACK;
230 }
231
232 /*
233 * Active close
234 *
235 * Step 1:
236 * The *server* side of this connect is VM, *server* tries to close
237 * the connection.
238 *
239 * Step 2:
240 * We will into CLOSE_WAIT status.
241 * We simplify the TCPS_FIN_WAIT_2, TCPS_TIME_WAIT and
242 * CLOSING status.
243 */
244 if (conn->tcp_state == TCPS_ESTABLISHED &&
245 (tcp_pkt->th_flags & (TH_ACK | TH_FIN)) == TH_FIN) {
246 conn->tcp_state = TCPS_FIN_WAIT_1;
247 }
248
249 return 0;
250 }
251
252 static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
253 NetClientState *sender,
254 unsigned flags,
255 const struct iovec *iov,
256 int iovcnt,
257 NetPacketSent *sent_cb)
258 {
259 RewriterState *s = FILTER_REWRITER(nf);
260 Connection *conn;
261 ConnectionKey key;
262 Packet *pkt;
263 ssize_t size = iov_size(iov, iovcnt);
264 ssize_t vnet_hdr_len = 0;
265 char *buf = g_malloc0(size);
266
267 iov_to_buf(iov, iovcnt, 0, buf, size);
268
269 if (s->vnet_hdr) {
270 vnet_hdr_len = nf->netdev->vnet_hdr_len;
271 }
272
273 pkt = packet_new(buf, size, vnet_hdr_len);
274 g_free(buf);
275
276 /*
277 * if we get tcp packet
278 * we will rewrite it to make secondary guest's
279 * connection established successfully
280 */
281 if (pkt && is_tcp_packet(pkt)) {
282
283 fill_connection_key(pkt, &key);
284
285 if (sender == nf->netdev) {
286 /*
287 * We need make tcp TX and RX packet
288 * into one connection.
289 */
290 reverse_connection_key(&key);
291 }
292
293 /* After failover we needn't change new TCP packet */
294 if (s->failover_mode &&
295 !connection_has_tracked(s->connection_track_table, &key)) {
296 goto out;
297 }
298
299 conn = connection_get(s->connection_track_table,
300 &key,
301 NULL);
302
303 if (sender == nf->netdev) {
304 /* NET_FILTER_DIRECTION_TX */
305 if (!handle_primary_tcp_pkt(s, conn, pkt, &key)) {
306 qemu_net_queue_send(s->incoming_queue, sender, 0,
307 (const uint8_t *)pkt->data, pkt->size, NULL);
308 packet_destroy(pkt, NULL);
309 pkt = NULL;
310 /*
311 * We block the packet here,after rewrite pkt
312 * and will send it
313 */
314 return 1;
315 }
316 } else {
317 /* NET_FILTER_DIRECTION_RX */
318 if (!handle_secondary_tcp_pkt(s, conn, pkt, &key)) {
319 qemu_net_queue_send(s->incoming_queue, sender, 0,
320 (const uint8_t *)pkt->data, pkt->size, NULL);
321 packet_destroy(pkt, NULL);
322 pkt = NULL;
323 /*
324 * We block the packet here,after rewrite pkt
325 * and will send it
326 */
327 return 1;
328 }
329 }
330 }
331
332 out:
333 packet_destroy(pkt, NULL);
334 pkt = NULL;
335 return 0;
336 }
337
338 static void reset_seq_offset(gpointer key, gpointer value, gpointer user_data)
339 {
340 Connection *conn = (Connection *)value;
341
342 conn->offset = 0;
343 }
344
345 static gboolean offset_is_nonzero(gpointer key,
346 gpointer value,
347 gpointer user_data)
348 {
349 Connection *conn = (Connection *)value;
350
351 return conn->offset ? true : false;
352 }
353
354 static void colo_rewriter_handle_event(NetFilterState *nf, int event,
355 Error **errp)
356 {
357 RewriterState *rs = FILTER_REWRITER(nf);
358
359 switch (event) {
360 case COLO_EVENT_CHECKPOINT:
361 g_hash_table_foreach(rs->connection_track_table,
362 reset_seq_offset, NULL);
363 break;
364 case COLO_EVENT_FAILOVER:
365 if (!g_hash_table_find(rs->connection_track_table,
366 offset_is_nonzero, NULL)) {
367 filter_rewriter_failover_mode(rs);
368 }
369 break;
370 default:
371 break;
372 }
373 }
374
375 static void colo_rewriter_cleanup(NetFilterState *nf)
376 {
377 RewriterState *s = FILTER_REWRITER(nf);
378
379 /* flush packets */
380 if (s->incoming_queue) {
381 filter_rewriter_flush(nf);
382 g_free(s->incoming_queue);
383 }
384 }
385
386 static void colo_rewriter_setup(NetFilterState *nf, Error **errp)
387 {
388 RewriterState *s = FILTER_REWRITER(nf);
389
390 s->connection_track_table = g_hash_table_new_full(connection_key_hash,
391 connection_key_equal,
392 g_free,
393 connection_destroy);
394 s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
395 }
396
397 static bool filter_rewriter_get_vnet_hdr(Object *obj, Error **errp)
398 {
399 RewriterState *s = FILTER_REWRITER(obj);
400
401 return s->vnet_hdr;
402 }
403
404 static void filter_rewriter_set_vnet_hdr(Object *obj,
405 bool value,
406 Error **errp)
407 {
408 RewriterState *s = FILTER_REWRITER(obj);
409
410 s->vnet_hdr = value;
411 }
412
413 static void filter_rewriter_init(Object *obj)
414 {
415 RewriterState *s = FILTER_REWRITER(obj);
416
417 s->vnet_hdr = false;
418 s->failover_mode = FAILOVER_MODE_OFF;
419 object_property_add_bool(obj, "vnet_hdr_support",
420 filter_rewriter_get_vnet_hdr,
421 filter_rewriter_set_vnet_hdr);
422 }
423
424 static void colo_rewriter_class_init(ObjectClass *oc, void *data)
425 {
426 NetFilterClass *nfc = NETFILTER_CLASS(oc);
427
428 nfc->setup = colo_rewriter_setup;
429 nfc->cleanup = colo_rewriter_cleanup;
430 nfc->receive_iov = colo_rewriter_receive_iov;
431 nfc->handle_event = colo_rewriter_handle_event;
432 }
433
434 static const TypeInfo colo_rewriter_info = {
435 .name = TYPE_FILTER_REWRITER,
436 .parent = TYPE_NETFILTER,
437 .class_init = colo_rewriter_class_init,
438 .instance_init = filter_rewriter_init,
439 .instance_size = sizeof(RewriterState),
440 };
441
442 static void register_types(void)
443 {
444 type_register_static(&colo_rewriter_info);
445 }
446
447 type_init(register_types);