1 #ifdef HAVE_CONFIG_H
2 # include <config.h>
3 #endif
4
5 #include <stdio.h>
6
7 #include "ntp_assert.h"
8 #include "ntp_syslog.h"
9 #include "ntp_stdlib.h"
10 #include "ntp_lists.h"
11 #include "recvbuff.h"
12 #include "iosignal.h"
13
14 #if (RECV_INC & (RECV_INC-1))
15 # error RECV_INC not a power of 2!
16 #endif
17 #if (RECV_BATCH & (RECV_BATCH - 1))
18 #error RECV_BATCH not a power of 2!
19 #endif
20 #if (RECV_BATCH < RECV_INC)
21 #error RECV_BATCH must be >= RECV_INC!
22 #endif
23
24 /*
25 * Memory allocation
26 */
27 static u_long volatile full_recvbufs; /* recvbufs on full_recv_fifo */
28 static u_long volatile free_recvbufs; /* recvbufs on free_recv_list */
29 static u_long volatile total_recvbufs; /* total recvbufs currently in use */
30 static u_long volatile lowater_adds; /* number of times we have added memory */
31 static u_long volatile buffer_shortfall;/* number of missed free receive buffers
32 between replenishments */
33 static u_long limit_recvbufs; /* maximum total of receive buffers */
34 static u_long emerg_recvbufs; /* emergency/urgent buffers to keep */
35
36 static DECL_FIFO_ANCHOR(recvbuf_t) full_recv_fifo;
37 static recvbuf_t * free_recv_list;
38
39 #if defined(SYS_WINNT)
40
41 /*
42 * For Windows we need to set up a lock to manipulate the
43 * recv buffers to prevent corruption. We keep it lock for as
44 * short a time as possible
45 */
46 static CRITICAL_SECTION RecvLock;
47 static CRITICAL_SECTION FreeLock;
48 # define LOCK_R() EnterCriticalSection(&RecvLock)
49 # define UNLOCK_R() LeaveCriticalSection(&RecvLock)
50 # define LOCK_F() EnterCriticalSection(&FreeLock)
51 # define UNLOCK_F() LeaveCriticalSection(&FreeLock)
52 #else
53 # define LOCK_R() do {} while (FALSE)
54 # define UNLOCK_R() do {} while (FALSE)
55 # define LOCK_F() do {} while (FALSE)
56 # define UNLOCK_F() do {} while (FALSE)
57 #endif
58
59 #ifdef DEBUG
60 static void uninit_recvbuff(void);
61 #endif
62
63
64 u_long
free_recvbuffs(void)65 free_recvbuffs (void)
66 {
67 return free_recvbufs;
68 }
69
70 u_long
full_recvbuffs(void)71 full_recvbuffs (void)
72 {
73 return full_recvbufs;
74 }
75
76 u_long
total_recvbuffs(void)77 total_recvbuffs (void)
78 {
79 return total_recvbufs;
80 }
81
82 u_long
lowater_additions(void)83 lowater_additions(void)
84 {
85 return lowater_adds;
86 }
87
88 static inline void
initialise_buffer(recvbuf_t * buff)89 initialise_buffer(recvbuf_t *buff)
90 {
91 ZERO(*buff);
92 }
93
94 static void
create_buffers(size_t nbufs)95 create_buffers(
96 size_t nbufs)
97 {
98 # ifndef DEBUG
99 static const u_int chunk = RECV_INC;
100 # else
101 /* Allocate each buffer individually so they can be free()d
102 * during ntpd shutdown on DEBUG builds to keep them out of heap
103 * leak reports.
104 */
105 static const u_int chunk = 1;
106 # endif
107
108 register recvbuf_t *bufp;
109 u_int i;
110 size_t abuf;
111
112 if (limit_recvbufs <= total_recvbufs)
113 return;
114
115 abuf = nbufs + buffer_shortfall;
116 buffer_shortfall = 0;
117
118 if (abuf < nbufs || abuf > RECV_BATCH)
119 abuf = RECV_BATCH; /* clamp on overflow */
120 else
121 abuf += (~abuf + 1) & (RECV_INC - 1); /* round up */
122
123 if (abuf > (limit_recvbufs - total_recvbufs))
124 abuf = limit_recvbufs - total_recvbufs;
125 abuf += (~abuf + 1) & (chunk - 1); /* round up */
126
127 while (abuf) {
128 bufp = calloc(chunk, sizeof(*bufp));
129 if (!bufp) {
130 limit_recvbufs = total_recvbufs;
131 break;
132 }
133 for (i = chunk; i; --i,++bufp) {
134 LINK_SLIST(free_recv_list, bufp, link);
135 }
136 free_recvbufs += chunk;
137 total_recvbufs += chunk;
138 abuf -= chunk;
139 }
140 ++lowater_adds;
141 }
142
143 void
init_recvbuff(int nbufs)144 init_recvbuff(int nbufs)
145 {
146
147 /*
148 * Init buffer free list and stat counters
149 */
150 free_recvbufs = total_recvbufs = 0;
151 full_recvbufs = lowater_adds = 0;
152
153 limit_recvbufs = RECV_TOOMANY;
154 emerg_recvbufs = RECV_CLOCK;
155
156 create_buffers(nbufs);
157
158 # if defined(SYS_WINNT)
159 InitializeCriticalSection(&RecvLock);
160 InitializeCriticalSection(&FreeLock);
161 # endif
162
163 # ifdef DEBUG
164 atexit(&uninit_recvbuff);
165 # endif
166 }
167
168
169 #ifdef DEBUG
170 static void
uninit_recvbuff(void)171 uninit_recvbuff(void)
172 {
173 recvbuf_t *rbunlinked;
174
175 for (;;) {
176 UNLINK_FIFO(rbunlinked, full_recv_fifo, link);
177 if (rbunlinked == NULL)
178 break;
179 free(rbunlinked);
180 }
181
182 for (;;) {
183 UNLINK_HEAD_SLIST(rbunlinked, free_recv_list, link);
184 if (rbunlinked == NULL)
185 break;
186 free(rbunlinked);
187 }
188 # if defined(SYS_WINNT)
189 DeleteCriticalSection(&FreeLock);
190 DeleteCriticalSection(&RecvLock);
191 # endif
192 }
193 #endif /* DEBUG */
194
195
196 /*
197 * freerecvbuf - make a single recvbuf available for reuse
198 */
199 void
freerecvbuf(recvbuf_t * rb)200 freerecvbuf(recvbuf_t *rb)
201 {
202 if (rb) {
203 if (--rb->used != 0) {
204 msyslog(LOG_ERR, "******** freerecvbuff non-zero usage: %d *******", rb->used);
205 rb->used = 0;
206 }
207 LOCK_F();
208 LINK_SLIST(free_recv_list, rb, link);
209 ++free_recvbufs;
210 UNLOCK_F();
211 }
212 }
213
214
215 void
add_full_recv_buffer(recvbuf_t * rb)216 add_full_recv_buffer(recvbuf_t *rb)
217 {
218 if (rb == NULL) {
219 msyslog(LOG_ERR, "add_full_recv_buffer received NULL buffer");
220 return;
221 }
222 LOCK_R();
223 LINK_FIFO(full_recv_fifo, rb, link);
224 ++full_recvbufs;
225 UNLOCK_R();
226 }
227
228
229 recvbuf_t *
get_free_recv_buffer(int urgent)230 get_free_recv_buffer(
231 int /*BOOL*/ urgent
232 )
233 {
234 recvbuf_t *buffer = NULL;
235
236 LOCK_F();
237 if (free_recvbufs > (urgent ? emerg_recvbufs : 0)) {
238 UNLINK_HEAD_SLIST(buffer, free_recv_list, link);
239 }
240
241 if (buffer != NULL) {
242 if (free_recvbufs)
243 --free_recvbufs;
244 initialise_buffer(buffer);
245 ++buffer->used;
246 } else {
247 ++buffer_shortfall;
248 }
249 UNLOCK_F();
250
251 return buffer;
252 }
253
254
255 #ifdef HAVE_IO_COMPLETION_PORT
256 recvbuf_t *
get_free_recv_buffer_alloc(int urgent)257 get_free_recv_buffer_alloc(
258 int /*BOOL*/ urgent
259 )
260 {
261 LOCK_F();
262 if (free_recvbufs <= emerg_recvbufs || buffer_shortfall > 0)
263 create_buffers(RECV_INC);
264 UNLOCK_F();
265 return get_free_recv_buffer(urgent);
266 }
267 #endif
268
269
270 recvbuf_t *
get_full_recv_buffer(void)271 get_full_recv_buffer(void)
272 {
273 recvbuf_t * rbuf;
274
275 /*
276 * make sure there are free buffers when we wander off to do
277 * lengthy packet processing with any buffer we grab from the
278 * full list.
279 *
280 * fixes malloc() interrupted by SIGIO risk (Bug 889)
281 */
282 LOCK_F();
283 if (free_recvbufs <= emerg_recvbufs || buffer_shortfall > 0)
284 create_buffers(RECV_INC);
285 UNLOCK_F();
286
287 /*
288 * try to grab a full buffer
289 */
290 LOCK_R();
291 UNLINK_FIFO(rbuf, full_recv_fifo, link);
292 if (rbuf != NULL && full_recvbufs)
293 --full_recvbufs;
294 UNLOCK_R();
295
296 return rbuf;
297 }
298
299
300 /*
301 * purge_recv_buffers_for_fd() - purges any previously-received input
302 * from a given file descriptor.
303 */
304 void
purge_recv_buffers_for_fd(int fd)305 purge_recv_buffers_for_fd(
306 int fd
307 )
308 {
309 recvbuf_t *rbufp;
310 recvbuf_t *next;
311 recvbuf_t *punlinked;
312 recvbuf_t *freelist = NULL;
313
314 /* We want to hold only one lock at a time. So we do a scan on
315 * the full buffer queue, collecting items as we go, and when
316 * done we spool the the collected items to 'freerecvbuf()'.
317 */
318 LOCK_R();
319
320 for (rbufp = HEAD_FIFO(full_recv_fifo);
321 rbufp != NULL;
322 rbufp = next)
323 {
324 next = rbufp->link;
325 # ifdef HAVE_IO_COMPLETION_PORT
326 if (rbufp->dstadr == NULL && rbufp->fd == fd)
327 # else
328 if (rbufp->fd == fd)
329 # endif
330 {
331 UNLINK_MID_FIFO(punlinked, full_recv_fifo,
332 rbufp, link, recvbuf_t);
333 INSIST(punlinked == rbufp);
334 if (full_recvbufs)
335 --full_recvbufs;
336 rbufp->link = freelist;
337 freelist = rbufp;
338 }
339 }
340
341 UNLOCK_R();
342
343 while (freelist) {
344 next = freelist->link;
345 freerecvbuf(freelist);
346 freelist = next;
347 }
348 }
349
350
351 /*
352 * Checks to see if there are buffers to process
353 */
has_full_recv_buffer(void)354 isc_boolean_t has_full_recv_buffer(void)
355 {
356 if (HEAD_FIFO(full_recv_fifo) != NULL)
357 return (ISC_TRUE);
358 else
359 return (ISC_FALSE);
360 }
361
362
363 #ifdef NTP_DEBUG_LISTS_H
364 void
check_gen_fifo_consistency(void * fifo)365 check_gen_fifo_consistency(void *fifo)
366 {
367 gen_fifo *pf;
368 gen_node *pthis;
369 gen_node **pptail;
370
371 pf = fifo;
372 REQUIRE((NULL == pf->phead && NULL == pf->pptail) ||
373 (NULL != pf->phead && NULL != pf->pptail));
374
375 pptail = &pf->phead;
376 for (pthis = pf->phead;
377 pthis != NULL;
378 pthis = pthis->link)
379 if (NULL != pthis->link)
380 pptail = &pthis->link;
381
382 REQUIRE(NULL == pf->pptail || pptail == pf->pptail);
383 }
384 #endif /* NTP_DEBUG_LISTS_H */
385