summaryrefslogtreecommitdiff
path: root/source/n/bind/bind-v9.16.0-tcp_quota_fix.patch
blob: bad95dddc19206cfd37317d14a76850eb0087c83 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index ae83f943d3..c85065f39d 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -356,7 +356,16 @@ struct isc_nmsocket {
 	 */
 	isc_quota_t *quota;
 	isc_quota_t *pquota;
-	bool	     overquota;
+
+	/*%
+	 * How many connections we have not accepted due to quota?
+	 * When we close a connection we need to accept a new one.
+	 */
+	int overquota;
+	/*%
+	 * How many active connections we have?
+	 */
+	int conns;
 
 	/*%
 	 * Socket statistics
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index f4361575cc..26728c1ba6 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -727,6 +727,11 @@ nmsocket_cleanup(isc_nmsocket_t *sock, bool dofree)
 		for (int i = 0; i < sock->nchildren; i++) {
 			if (!atomic_load(&sock->children[i].destroying)) {
 				nmsocket_cleanup(&sock->children[i], false);
+				if (sock->statsindex != NULL) {
+					isc__nm_decstats(
+						sock->mgr,
+						sock->statsindex[STATID_ACTIVE]);
+				}
 			}
 		}
 
@@ -738,6 +743,9 @@ nmsocket_cleanup(isc_nmsocket_t *sock, bool dofree)
 		sock->children = NULL;
 		sock->nchildren = 0;
 	}
+	if (sock->statsindex != NULL) {
+		isc__nm_decstats(sock->mgr, sock->statsindex[STATID_ACTIVE]);
+	}
 
 	if (sock->tcphandle != NULL) {
 		isc_nmhandle_unref(sock->tcphandle);
@@ -854,8 +862,6 @@ isc__nmsocket_prep_destroy(isc_nmsocket_t *sock)
 	if (sock->children != NULL) {
 		for (int i = 0; i < sock->nchildren; i++) {
 			atomic_store(&sock->children[i].active, false);
-			isc__nm_decstats(sock->mgr,
-					 sock->statsindex[STATID_ACTIVE]);
 		}
 	}
 
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index a83fede0d2..58ffd3c404 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -26,12 +26,28 @@
 #include <isc/region.h>
 #include <isc/result.h>
 #include <isc/sockaddr.h>
+#include <isc/stdtime.h>
 #include <isc/thread.h>
 #include <isc/util.h>
 
 #include "netmgr-int.h"
 #include "uv-compat.h"
 
+static atomic_uint_fast32_t last_tcpquota_log = ATOMIC_VAR_INIT(0);
+
+static bool
+can_log_tcp_quota() {
+	isc_stdtime_t now, last;
+
+	isc_stdtime_get(&now);
+	last = atomic_exchange_relaxed(&last_tcpquota_log, now);
+	if (now != last) {
+		return (true);
+	}
+
+	return (false);
+}
+
 static int
 tcp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req);
 
@@ -668,9 +684,6 @@ read_cb(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf)
 	}
 
 	isc__nm_free_uvbuf(sock, buf);
-	if (sock->quota) {
-		isc_quota_detach(&sock->quota);
-	}
 
 	/*
 	 * This might happen if the inner socket is closing.  It means that
@@ -699,6 +712,7 @@ accept_connection(isc_nmsocket_t *ssock)
 	struct sockaddr_storage ss;
 	isc_sockaddr_t		local;
 	int			r;
+	bool overquota = false;
 
 	REQUIRE(VALID_NMSOCK(ssock));
 	REQUIRE(ssock->tid == isc_nm_tid());
@@ -711,10 +725,25 @@ accept_connection(isc_nmsocket_t *ssock)
 
 	if (ssock->pquota != NULL) {
 		result = isc_quota_attach(ssock->pquota, &quota);
+
+		/*
+		 * We share the quota between all TCP sockets. Others
+		 * may have used up all the quota slots, in which case
+		 * this socket could starve. So we only fail here if we
+		 * already had at least one active connection on this
+		 * socket. This guarantees that we'll maintain some level
+		 * of service while over quota, and will resume normal
+		 * service when the quota comes back down.
+		 */
 		if (result != ISC_R_SUCCESS) {
-			isc__nm_incstats(ssock->mgr,
-					 ssock->statsindex[STATID_ACCEPTFAIL]);
-			return (result);
+			ssock->overquota++;
+			overquota = true;
+			if (ssock->conns > 0) {
+				isc__nm_incstats(
+					ssock->mgr,
+					ssock->statsindex[STATID_ACCEPTFAIL]);
+				return (result);
+			}
 		}
 	}
 
@@ -761,6 +790,7 @@ accept_connection(isc_nmsocket_t *ssock)
 	}
 
 	isc_nmsocket_attach(ssock, &csock->server);
+	ssock->conns++;
 
 	handle = isc__nmhandle_get(csock, NULL, &local);
 
@@ -779,6 +809,9 @@ error:
 	if (csock->quota != NULL) {
 		isc_quota_detach(&csock->quota);
 	}
+	if (overquota) {
+		ssock->overquota--;
+	}
 	/* We need to detach it properly to make sure uv_close is called. */
 	isc_nmsocket_detach(&csock);
 	return (result);
@@ -793,14 +826,14 @@ tcp_connection_cb(uv_stream_t *server, int status)
 	UNUSED(status);
 
 	result = accept_connection(ssock);
-	if (result != ISC_R_SUCCESS) {
-		if (result == ISC_R_QUOTA || result == ISC_R_SOFTQUOTA) {
-			ssock->overquota = true;
+	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
+		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
+		    can_log_tcp_quota()) {
+			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
+				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
+				      "TCP connection failed: %s",
+				      isc_result_totext(result));
 		}
-		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-			      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-			      "TCP connection failed: %s",
-			      isc_result_totext(result));
 	}
 }
 
@@ -936,17 +969,27 @@ tcp_close_direct(isc_nmsocket_t *sock)
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(sock->tid == isc_nm_tid());
 	REQUIRE(sock->type == isc_nm_tcpsocket);
+	isc_nmsocket_t *ssock = sock->server;
 
 	if (sock->quota != NULL) {
-		isc_nmsocket_t *ssock = sock->server;
-
 		isc_quota_detach(&sock->quota);
-
-		if (ssock->overquota) {
+	}
+	if (ssock != NULL) {
+		ssock->conns--;
+		while (ssock->conns == 0 && ssock->overquota > 0) {
+			ssock->overquota--;
 			isc_result_t result = accept_connection(ssock);
-			if (result != ISC_R_QUOTA &&
-			    result != ISC_R_SOFTQUOTA) {
-				ssock->overquota = false;
+			if (result == ISC_R_SUCCESS || result == ISC_R_NOCONN) {
+				continue;
+			}
+			if ((result != ISC_R_QUOTA &&
+			     result != ISC_R_SOFTQUOTA) ||
+			    can_log_tcp_quota()) {
+				isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
+					      ISC_LOGMODULE_NETMGR,
+					      ISC_LOG_ERROR,
+					      "TCP connection failed: %s",
+					      isc_result_totext(result));
 			}
 		}
 	}
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index e384b73be9..f89eb359af 100644
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -43,6 +43,9 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_region_t *region, void *arg);
 static void
 resume_processing(void *arg);
 
+static void
+tcpdns_close_direct(isc_nmsocket_t *sock);
+
 static inline size_t
 dnslen(unsigned char *base)
 {
@@ -82,7 +85,6 @@ timer_close_cb(uv_handle_t *handle)
 {
 	isc_nmsocket_t *sock = (isc_nmsocket_t *)uv_handle_get_data(handle);
 	INSIST(VALID_NMSOCK(sock));
-	atomic_store(&sock->closed, true);
 	isc_nmsocket_detach(&sock);
 }
 
@@ -94,9 +96,7 @@ dnstcp_readtimeout(uv_timer_t *timer)
 
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(sock->tid == isc_nm_tid());
-
-	isc_nmsocket_detach(&sock->outer);
-	uv_close((uv_handle_t *)&sock->timer, timer_close_cb);
+	tcpdns_close_direct(sock);
 }
 
 /*
@@ -252,7 +252,9 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_region_t *region, void *arg)
 		 * We have a packet: stop timeout timers
 		 */
 		atomic_store(&dnssock->outer->processing, true);
-		uv_timer_stop(&dnssock->timer);
+		if (dnssock->timer_initialized) {
+			uv_timer_stop(&dnssock->timer);
+		}
 
 		if (atomic_load(&dnssock->sequential)) {
 			/*
@@ -399,8 +401,10 @@ resume_processing(void *arg)
 	if (atomic_load(&sock->ah) == 0) {
 		/* Nothing is active; sockets can timeout now */
 		atomic_store(&sock->outer->processing, false);
-		uv_timer_start(&sock->timer, dnstcp_readtimeout,
-			       sock->read_timeout, 0);
+		if (sock->timer_initialized) {
+			uv_timer_start(&sock->timer, dnstcp_readtimeout,
+				       sock->read_timeout, 0);
+		}
 	}
 
 	/*
@@ -413,7 +417,9 @@ resume_processing(void *arg)
 		result = processbuffer(sock, &handle);
 		if (result == ISC_R_SUCCESS) {
 			atomic_store(&sock->outer->processing, true);
-			uv_timer_stop(&sock->timer);
+			if (sock->timer_initialized) {
+				uv_timer_stop(&sock->timer);
+			}
 			isc_nmhandle_unref(handle);
 		} else if (sock->outer != NULL) {
 			isc_nm_resumeread(sock->outer);
@@ -441,7 +447,9 @@ resume_processing(void *arg)
 			break;
 		}
 
-		uv_timer_stop(&sock->timer);
+		if (sock->timer_initialized) {
+			uv_timer_stop(&sock->timer);
+		}
 		atomic_store(&sock->outer->processing, true);
 		isc_nmhandle_unref(dnshandle);
 	} while (atomic_load(&sock->ah) < TCPDNS_CLIENTS_PER_CONN);
@@ -507,18 +515,29 @@ static void
 tcpdns_close_direct(isc_nmsocket_t *sock)
 {
 	REQUIRE(sock->tid == isc_nm_tid());
-	if (sock->outer != NULL) {
-		sock->outer->rcb.recv = NULL;
-		isc_nmsocket_detach(&sock->outer);
-	}
-	if (sock->listener != NULL) {
-		isc_nmsocket_detach(&sock->listener);
-	}
 	/* We don't need atomics here, it's all in single network thread */
 	if (sock->timer_initialized) {
+		/*
+		 * We need to fire the timer callback to clean it up,
+		 * it will then call us again (via detach) so that we
+		 * can finally close the socket.
+		 */
 		sock->timer_initialized = false;
 		uv_timer_stop(&sock->timer);
 		uv_close((uv_handle_t *)&sock->timer, timer_close_cb);
+	} else {
+		/*
+		 * At this point we're certain that there are no external
+		 * references, we can close everything.
+		 */
+		if (sock->outer != NULL) {
+			sock->outer->rcb.recv = NULL;
+			isc_nmsocket_detach(&sock->outer);
+		}
+		if (sock->listener != NULL) {
+			isc_nmsocket_detach(&sock->listener);
+		}
+		atomic_store(&sock->closed, true);
 	}
 }
 
diff --git a/lib/isc/netmgr/uverr2result.c b/lib/isc/netmgr/uverr2result.c
index b6a8065e3e..9781454ca6 100644
--- a/lib/isc/netmgr/uverr2result.c
+++ b/lib/isc/netmgr/uverr2result.c
@@ -38,6 +38,8 @@ isc___nm_uverr2result(int uverr, bool dolog, const char *file,
 		return (ISC_R_INVALIDFILE);
 	case UV_ENOENT:
 		return (ISC_R_FILENOTFOUND);
+	case UV_EAGAIN:
+		return (ISC_R_NOCONN);
 	case UV_EACCES:
 	case UV_EPERM:
 		return (ISC_R_NOPERM);