ratectrl.c revision 168515
1/* 2 * Copyright (c) 2003 Sendmail, Inc. and its suppliers. 3 * All rights reserved. 4 * 5 * By using this file, you agree to the terms and conditions set 6 * forth in the LICENSE file which can be found at the top level of 7 * the sendmail distribution. 8 * 9 * Contributed by Jose Marcio Martins da Cruz - Ecole des Mines de Paris 10 * Jose-Marcio.Martins@ensmp.fr 11 */ 12 13/* a part of this code is based on inetd.c for which this copyright applies: */ 14/* 15 * Copyright (c) 1983, 1991, 1993, 1994 16 * The Regents of the University of California. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. All advertising materials mentioning features or use of this software 27 * must display the following acknowledgement: 28 * This product includes software developed by the University of 29 * California, Berkeley and its contributors. 30 * 4. Neither the name of the University nor the names of its contributors 31 * may be used to endorse or promote products derived from this software 32 * without specific prior written permission. 33 * 34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 44 * SUCH DAMAGE. 45 */ 46 47#include <sendmail.h> 48SM_RCSID("@(#)$Id: ratectrl.c,v 8.11 2006/08/15 23:24:57 ca Exp $") 49 50/* 51** stuff included - given some warnings (inet_ntoa) 52** - surely not everything is needed 53*/ 54 55#if NETINET || NETINET6 56# include <arpa/inet.h> 57#endif /* NETINET || NETINET6 */ 58 59#include <sm/time.h> 60 61#ifndef HASH_ALG 62# define HASH_ALG 2 63#endif /* HASH_ALG */ 64 65#ifndef RATECTL_DEBUG 66# define RATECTL_DEBUG 0 67#endif /* RATECTL_DEBUG */ 68 69/* forward declarations */ 70static int client_rate __P((time_t, SOCKADDR *, bool)); 71static int total_rate __P((time_t, bool)); 72#if 0 73static int sockaddrcmp __P((SOCKADDR *, SOCKADDR *)); 74#endif /* 0 */ 75 76/* 77** CONNECTION_RATE_CHECK - updates connection history data 78** and computes connection rate for the given host 79** 80** Parameters: 81** hostaddr -- ip address of smtp client 82** e -- envelope 83** 84** Returns: 85** true (always) 86** 87** Side Effects: 88** updates connection history 89** 90** Warnings: 91** For each connection, this call shall be 92** done only once with the value true for the 93** update parameter. 94** Typically, this call is done with the value 95** true by the father, and once again with 96** the value false by the children. 97** 98*/ 99 100bool 101connection_rate_check(hostaddr, e) 102 SOCKADDR *hostaddr; 103 ENVELOPE *e; 104{ 105 time_t now; 106 int totalrate, clientrate; 107 static int clientconn = 0; 108 109 now = time(NULL); 110#if RATECTL_DEBUG 111 sm_syslog(LOG_INFO, NOQID, "connection_rate_check entering..."); 112#endif /* RATECTL_DEBUG */ 113 114 /* update server connection rate */ 115 totalrate = total_rate(now, e == NULL); 116#if RATECTL_DEBUG 117 sm_syslog(LOG_INFO, NOQID, "global connection rate: %d", globalRate); 118#endif /* RATECTL_DEBUG */ 119 120 /* update client connection rate */ 121 clientrate = client_rate(now, hostaddr, e == NULL); 122 123 if (e == NULL) 124 clientconn = count_open_connections(hostaddr); 125 126 if (e != NULL) 127 { 128 char s[16]; 129 130 sm_snprintf(s, sizeof(s), "%d", clientrate); 131 macdefine(&e->e_macro, A_TEMP, macid("{client_rate}"), s); 132 sm_snprintf(s, sizeof(s), "%d", totalrate); 133 macdefine(&e->e_macro, A_TEMP, macid("{total_rate}"), s); 134 sm_snprintf(s, sizeof(s), "%d", clientconn); 135 macdefine(&e->e_macro, A_TEMP, macid("{client_connections}"), 136 s); 137 } 138 return true; 139} 140 141/* 142** Data declarations needed to evaluate connection rate 143*/ 144 145static int CollTime = 60; 146 147/* this should be a power of 2, otherwise CPMHMASK doesn't work well */ 148#ifndef CPMHSIZE 149# define CPMHSIZE 1024 150#endif /* CPMHSIZE */ 151 152#define CPMHMASK (CPMHSIZE-1) 153 154#ifndef MAX_CT_STEPS 155# define MAX_CT_STEPS 10 156#endif /* MAX_CT_STEPS */ 157 158/* 159** time granularity: 10s (that's one "tick") 160** will be initialised to ConnectionRateWindowSize/CHTSIZE 161** before being used the first time 162*/ 163 164static int ChtGran = -1; 165 166#define CHTSIZE 6 167 168/* Number of connections for a certain "tick" */ 169typedef struct CTime 170{ 171 unsigned long ct_Ticks; 172 int ct_Count; 173} 174CTime_T; 175 176typedef struct CHash 177{ 178#if NETINET6 && NETINET 179 union 180 { 181 struct in_addr c4_Addr; 182 struct in6_addr c6_Addr; 183 } cu_Addr; 184# define ch_Addr4 cu_Addr.c4_Addr 185# define ch_Addr6 cu_Addr.c6_Addr 186#else /* NETINET6 && NETINET */ 187# if NETINET6 188 struct in6_addr ch_Addr; 189# define ch_Addr6 ch_Addr 190# else /* NETINET6 */ 191 struct in_addr ch_Addr; 192# define ch_Addr4 ch_Addr 193# endif /* NETINET6 */ 194#endif /* NETINET6 && NETINET */ 195 196 int ch_Family; 197 time_t ch_LTime; 198 unsigned long ch_colls; 199 200 /* 6 buckets for ticks: 60s */ 201 CTime_T ch_Times[CHTSIZE]; 202} 203CHash_T; 204 205static CHash_T CHashAry[CPMHSIZE]; 206static bool CHashAryOK = false; 207 208/* 209** CLIENT_RATE - Evaluate connection rate per smtp client 210** 211** Parameters: 212** now - current time in secs 213** saddr - client address 214** update - update data / check only 215** 216** Returns: 217** connection rate (connections / ConnectionRateWindowSize) 218** 219** Side effects: 220** update static global data 221** 222*/ 223 224static int 225client_rate(now, saddr, update) 226 time_t now; 227 SOCKADDR *saddr; 228 bool update; 229{ 230 unsigned int hv; 231 int i; 232 int cnt; 233 bool coll; 234 CHash_T *chBest = NULL; 235 unsigned int ticks; 236 237 cnt = 0; 238 hv = 0xABC3D20F; 239 if (ChtGran < 0) 240 ChtGran = ConnectionRateWindowSize / CHTSIZE; 241 if (ChtGran <= 0) 242 ChtGran = 10; 243 244 ticks = now / ChtGran; 245 246 if (!CHashAryOK) 247 { 248 memset(CHashAry, 0, sizeof(CHashAry)); 249 CHashAryOK = true; 250 } 251 252 { 253 char *p; 254 int addrlen; 255#if HASH_ALG != 1 256 int c, d; 257#endif /* HASH_ALG != 1 */ 258 259 switch (saddr->sa.sa_family) 260 { 261#if NETINET 262 case AF_INET: 263 p = (char *)&saddr->sin.sin_addr; 264 addrlen = sizeof(struct in_addr); 265 break; 266#endif /* NETINET */ 267#if NETINET6 268 case AF_INET6: 269 p = (char *)&saddr->sin6.sin6_addr; 270 addrlen = sizeof(struct in6_addr); 271 break; 272#endif /* NETINET6 */ 273 default: 274 /* should not happen */ 275 return -1; 276 } 277 278 /* compute hash value */ 279 for (i = 0; i < addrlen; ++i, ++p) 280#if HASH_ALG == 1 281 hv = (hv << 5) ^ (hv >> 23) ^ *p; 282 hv = (hv ^ (hv >> 16)); 283#elif HASH_ALG == 2 284 { 285 d = *p; 286 c = d; 287 c ^= c<<6; 288 hv += (c<<11) ^ (c>>1); 289 hv ^= (d<<14) + (d<<7) + (d<<4) + d; 290 } 291#elif HASH_ALG == 3 292 { 293 hv = (hv << 4) + *p; 294 d = hv & 0xf0000000; 295 if (d != 0) 296 { 297 hv ^= (d >> 24); 298 hv ^= d; 299 } 300 } 301#else /* HASH_ALG == 1 */ 302 hv = ((hv << 1) ^ (*p & 0377)) % cctx->cc_size; 303#endif /* HASH_ALG == 1 */ 304 } 305 306 coll = true; 307 for (i = 0; i < MAX_CT_STEPS; ++i) 308 { 309 CHash_T *ch = &CHashAry[(hv + i) & CPMHMASK]; 310 311#if NETINET 312 if (saddr->sa.sa_family == AF_INET && 313 ch->ch_Family == AF_INET && 314 (saddr->sin.sin_addr.s_addr == ch->ch_Addr4.s_addr || 315 ch->ch_Addr4.s_addr == 0)) 316 { 317 chBest = ch; 318 coll = false; 319 break; 320 } 321#endif /* NETINET */ 322#if NETINET6 323 if (saddr->sa.sa_family == AF_INET6 && 324 ch->ch_Family == AF_INET6 && 325 (IN6_ARE_ADDR_EQUAL(&saddr->sin6.sin6_addr, 326 &ch->ch_Addr6) != 0 || 327 IN6_IS_ADDR_UNSPECIFIED(&ch->ch_Addr6))) 328 { 329 chBest = ch; 330 coll = false; 331 break; 332 } 333#endif /* NETINET6 */ 334 if (chBest == NULL || ch->ch_LTime == 0 || 335 ch->ch_LTime < chBest->ch_LTime) 336 chBest = ch; 337 } 338 339 /* Let's update data... */ 340 if (update) 341 { 342 if (coll && (now - chBest->ch_LTime < CollTime)) 343 { 344 /* 345 ** increment the number of collisions last 346 ** CollTime for this client 347 */ 348 349 chBest->ch_colls++; 350 351 /* 352 ** Maybe shall log if collision rate is too high... 353 ** and take measures to resize tables 354 ** if this is the case 355 */ 356 } 357 358 /* 359 ** If it's not a match, then replace the data. 360 ** Note: this purges the history of a colliding entry, 361 ** which may cause "overruns", i.e., if two entries are 362 ** "cancelling" each other out, then they may exceed 363 ** the limits that are set. This might be mitigated a bit 364 ** by the above "best of 5" function however. 365 ** 366 ** Alternative approach: just use the old data, which may 367 ** cause false positives however. 368 ** To activate this, change deactivate following memset call. 369 */ 370 371 if (coll) 372 { 373#if NETINET 374 if (saddr->sa.sa_family == AF_INET) 375 { 376 chBest->ch_Family = AF_INET; 377 chBest->ch_Addr4 = saddr->sin.sin_addr; 378 } 379#endif /* NETINET */ 380#if NETINET6 381 if (saddr->sa.sa_family == AF_INET6) 382 { 383 chBest->ch_Family = AF_INET6; 384 chBest->ch_Addr6 = saddr->sin6.sin6_addr; 385 } 386#endif /* NETINET6 */ 387#if 1 388 memset(chBest->ch_Times, '\0', 389 sizeof(chBest->ch_Times)); 390#endif /* 1 */ 391 } 392 393 chBest->ch_LTime = now; 394 { 395 CTime_T *ct = &chBest->ch_Times[ticks % CHTSIZE]; 396 397 if (ct->ct_Ticks != ticks) 398 { 399 ct->ct_Ticks = ticks; 400 ct->ct_Count = 0; 401 } 402 ++ct->ct_Count; 403 } 404 } 405 406 /* Now let's count connections on the window */ 407 for (i = 0; i < CHTSIZE; ++i) 408 { 409 CTime_T *ct = &chBest->ch_Times[i]; 410 411 if (ct->ct_Ticks <= ticks && ct->ct_Ticks >= ticks - CHTSIZE) 412 cnt += ct->ct_Count; 413 } 414 415#if RATECTL_DEBUG 416 sm_syslog(LOG_WARNING, NOQID, 417 "cln: cnt=(%d), CHTSIZE=(%d), ChtGran=(%d)", 418 cnt, CHTSIZE, ChtGran); 419#endif /* RATECTL_DEBUG */ 420 return cnt; 421} 422 423/* 424** TOTAL_RATE - Evaluate global connection rate 425** 426** Parameters: 427** now - current time in secs 428** update - update data / check only 429** 430** Returns: 431** connection rate (connections / ConnectionRateWindowSize) 432*/ 433 434static CTime_T srv_Times[CHTSIZE]; 435static bool srv_Times_OK = false; 436 437static int 438total_rate(now, update) 439 time_t now; 440 bool update; 441{ 442 int i; 443 int cnt = 0; 444 CTime_T *ct; 445 unsigned int ticks; 446 447 if (ChtGran < 0) 448 ChtGran = ConnectionRateWindowSize / CHTSIZE; 449 if (ChtGran == 0) 450 ChtGran = 10; 451 ticks = now / ChtGran; 452 if (!srv_Times_OK) 453 { 454 memset(srv_Times, 0, sizeof(srv_Times)); 455 srv_Times_OK = true; 456 } 457 458 /* Let's update data */ 459 if (update) 460 { 461 ct = &srv_Times[ticks % CHTSIZE]; 462 463 if (ct->ct_Ticks != ticks) 464 { 465 ct->ct_Ticks = ticks; 466 ct->ct_Count = 0; 467 } 468 ++ct->ct_Count; 469 } 470 471 /* Let's count connections on the window */ 472 for (i = 0; i < CHTSIZE; ++i) 473 { 474 ct = &srv_Times[i]; 475 476 if (ct->ct_Ticks <= ticks && ct->ct_Ticks >= ticks - CHTSIZE) 477 cnt += ct->ct_Count; 478 } 479 480#if RATECTL_DEBUG 481 sm_syslog(LOG_WARNING, NOQID, 482 "srv: cnt=(%d), CHTSIZE=(%d), ChtGran=(%d)", 483 cnt, CHTSIZE, ChtGran); 484#endif /* RATECTL_DEBUG */ 485 486 return cnt; 487} 488 489#if 0 490/* 491** SOCKADDRCMP - compare two SOCKADDR structures 492** this function may be used to compare SOCKADDR 493** structures when using bsearch and qsort functions 494** in the same way we do with strcmp 495** 496** Parameters: 497** a, b - addresses 498** 499** Returns: 500** 1 if a > b 501** -1 if a < b 502** 0 if a = b 503** 504** OBS: This call isn't used at the moment, it will 505** be used when code will be extended to work with IPV6 506*/ 507 508static int 509sockaddrcmp(a, b) 510 SOCKADDR *a; 511 SOCKADDR *b; 512{ 513 if (a->sa.sa_family > b->sa.sa_family) 514 return 1; 515 if (a->sa.sa_family < b->sa.sa_family) 516 return -1; 517 518 switch (a->sa.sa_family) 519 { 520 case AF_INET: 521 if (a->sin.sin_addr.s_addr > b->sin.sin_addr.s_addr) 522 return 1; 523 if (a->sin.sin_addr.s_addr < b->sin.sin_addr.s_addr) 524 return -1; 525 return 0; 526 break; 527 528 case AF_INET6: 529 /* TO BE DONE */ 530 break; 531 } 532 return 0; 533} 534#endif /* 0 */ 535