1 /* 2 * Copyright (c) 2003 Proofpoint, 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> 48 SM_RCSID("@(#)$Id: ratectrl.c,v 8.14 2013-11-22 20:51:56 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 */ 70 static int client_rate __P((time_t, SOCKADDR *, bool)); 71 static int total_rate __P((time_t, bool)); 72 73 /* 74 ** CONNECTION_RATE_CHECK - updates connection history data 75 ** and computes connection rate for the given host 76 ** 77 ** Parameters: 78 ** hostaddr -- ip address of smtp client 79 ** e -- envelope 80 ** 81 ** Returns: 82 ** true (always) 83 ** 84 ** Side Effects: 85 ** updates connection history 86 ** 87 ** Warnings: 88 ** For each connection, this call shall be 89 ** done only once with the value true for the 90 ** update parameter. 91 ** Typically, this call is done with the value 92 ** true by the father, and once again with 93 ** the value false by the children. 94 ** 95 */ 96 97 bool 98 connection_rate_check(hostaddr, e) 99 SOCKADDR *hostaddr; 100 ENVELOPE *e; 101 { 102 time_t now; 103 int totalrate, clientrate; 104 static int clientconn = 0; 105 106 now = time(NULL); 107 #if RATECTL_DEBUG 108 sm_syslog(LOG_INFO, NOQID, "connection_rate_check entering..."); 109 #endif /* RATECTL_DEBUG */ 110 111 /* update server connection rate */ 112 totalrate = total_rate(now, e == NULL); 113 #if RATECTL_DEBUG 114 sm_syslog(LOG_INFO, NOQID, "global connection rate: %d", totalrate); 115 #endif /* RATECTL_DEBUG */ 116 117 /* update client connection rate */ 118 clientrate = client_rate(now, hostaddr, e == NULL); 119 120 if (e == NULL) 121 clientconn = count_open_connections(hostaddr); 122 123 if (e != NULL) 124 { 125 char s[16]; 126 127 sm_snprintf(s, sizeof(s), "%d", clientrate); 128 macdefine(&e->e_macro, A_TEMP, macid("{client_rate}"), s); 129 sm_snprintf(s, sizeof(s), "%d", totalrate); 130 macdefine(&e->e_macro, A_TEMP, macid("{total_rate}"), s); 131 sm_snprintf(s, sizeof(s), "%d", clientconn); 132 macdefine(&e->e_macro, A_TEMP, macid("{client_connections}"), 133 s); 134 } 135 return true; 136 } 137 138 /* 139 ** Data declarations needed to evaluate connection rate 140 */ 141 142 static int CollTime = 60; 143 144 /* this should be a power of 2, otherwise CPMHMASK doesn't work well */ 145 #ifndef CPMHSIZE 146 # define CPMHSIZE 1024 147 #endif /* CPMHSIZE */ 148 149 #define CPMHMASK (CPMHSIZE-1) 150 151 #ifndef MAX_CT_STEPS 152 # define MAX_CT_STEPS 10 153 #endif /* MAX_CT_STEPS */ 154 155 /* 156 ** time granularity: 10s (that's one "tick") 157 ** will be initialised to ConnectionRateWindowSize/CHTSIZE 158 ** before being used the first time 159 */ 160 161 static int ChtGran = -1; 162 163 #define CHTSIZE 6 164 165 /* Number of connections for a certain "tick" */ 166 typedef struct CTime 167 { 168 unsigned long ct_Ticks; 169 int ct_Count; 170 } 171 CTime_T; 172 173 typedef struct CHash 174 { 175 #if NETINET6 && NETINET 176 union 177 { 178 struct in_addr c4_Addr; 179 struct in6_addr c6_Addr; 180 } cu_Addr; 181 # define ch_Addr4 cu_Addr.c4_Addr 182 # define ch_Addr6 cu_Addr.c6_Addr 183 #else /* NETINET6 && NETINET */ 184 # if NETINET6 185 struct in6_addr ch_Addr; 186 # define ch_Addr6 ch_Addr 187 # else /* NETINET6 */ 188 struct in_addr ch_Addr; 189 # define ch_Addr4 ch_Addr 190 # endif /* NETINET6 */ 191 #endif /* NETINET6 && NETINET */ 192 193 int ch_Family; 194 time_t ch_LTime; 195 unsigned long ch_colls; 196 197 /* 6 buckets for ticks: 60s */ 198 CTime_T ch_Times[CHTSIZE]; 199 } 200 CHash_T; 201 202 static CHash_T CHashAry[CPMHSIZE]; 203 static bool CHashAryOK = false; 204 205 /* 206 ** CLIENT_RATE - Evaluate connection rate per smtp client 207 ** 208 ** Parameters: 209 ** now - current time in secs 210 ** saddr - client address 211 ** update - update data / check only 212 ** 213 ** Returns: 214 ** connection rate (connections / ConnectionRateWindowSize) 215 ** 216 ** Side effects: 217 ** update static global data 218 ** 219 */ 220 221 static int 222 client_rate(now, saddr, update) 223 time_t now; 224 SOCKADDR *saddr; 225 bool update; 226 { 227 unsigned int hv; 228 int i; 229 int cnt; 230 bool coll; 231 CHash_T *chBest = NULL; 232 unsigned int ticks; 233 234 cnt = 0; 235 hv = 0xABC3D20F; 236 if (ChtGran < 0) 237 ChtGran = ConnectionRateWindowSize / CHTSIZE; 238 if (ChtGran <= 0) 239 ChtGran = 10; 240 241 ticks = now / ChtGran; 242 243 if (!CHashAryOK) 244 { 245 memset(CHashAry, 0, sizeof(CHashAry)); 246 CHashAryOK = true; 247 } 248 249 { 250 char *p; 251 int addrlen; 252 #if HASH_ALG != 1 253 int c, d; 254 #endif /* HASH_ALG != 1 */ 255 256 switch (saddr->sa.sa_family) 257 { 258 #if NETINET 259 case AF_INET: 260 p = (char *)&saddr->sin.sin_addr; 261 addrlen = sizeof(struct in_addr); 262 break; 263 #endif /* NETINET */ 264 #if NETINET6 265 case AF_INET6: 266 p = (char *)&saddr->sin6.sin6_addr; 267 addrlen = sizeof(struct in6_addr); 268 break; 269 #endif /* NETINET6 */ 270 default: 271 /* should not happen */ 272 return -1; 273 } 274 275 /* compute hash value */ 276 for (i = 0; i < addrlen; ++i, ++p) 277 #if HASH_ALG == 1 278 hv = (hv << 5) ^ (hv >> 23) ^ *p; 279 hv = (hv ^ (hv >> 16)); 280 #elif HASH_ALG == 2 281 { 282 d = *p; 283 c = d; 284 c ^= c<<6; 285 hv += (c<<11) ^ (c>>1); 286 hv ^= (d<<14) + (d<<7) + (d<<4) + d; 287 } 288 #elif HASH_ALG == 3 289 { 290 hv = (hv << 4) + *p; 291 d = hv & 0xf0000000; 292 if (d != 0) 293 { 294 hv ^= (d >> 24); 295 hv ^= d; 296 } 297 } 298 #else /* HASH_ALG == 1 */ 299 hv = ((hv << 1) ^ (*p & 0377)) % cctx->cc_size; 300 #endif /* HASH_ALG == 1 */ 301 } 302 303 coll = true; 304 for (i = 0; i < MAX_CT_STEPS; ++i) 305 { 306 CHash_T *ch = &CHashAry[(hv + i) & CPMHMASK]; 307 308 #if NETINET 309 if (saddr->sa.sa_family == AF_INET && 310 ch->ch_Family == AF_INET && 311 (saddr->sin.sin_addr.s_addr == ch->ch_Addr4.s_addr || 312 ch->ch_Addr4.s_addr == 0)) 313 { 314 chBest = ch; 315 coll = false; 316 break; 317 } 318 #endif /* NETINET */ 319 #if NETINET6 320 if (saddr->sa.sa_family == AF_INET6 && 321 ch->ch_Family == AF_INET6 && 322 (IN6_ARE_ADDR_EQUAL(&saddr->sin6.sin6_addr, 323 &ch->ch_Addr6) != 0 || 324 IN6_IS_ADDR_UNSPECIFIED(&ch->ch_Addr6))) 325 { 326 chBest = ch; 327 coll = false; 328 break; 329 } 330 #endif /* NETINET6 */ 331 if (chBest == NULL || ch->ch_LTime == 0 || 332 ch->ch_LTime < chBest->ch_LTime) 333 chBest = ch; 334 } 335 336 /* Let's update data... */ 337 if (update) 338 { 339 if (coll && (now - chBest->ch_LTime < CollTime)) 340 { 341 /* 342 ** increment the number of collisions last 343 ** CollTime for this client 344 */ 345 346 chBest->ch_colls++; 347 348 /* 349 ** Maybe shall log if collision rate is too high... 350 ** and take measures to resize tables 351 ** if this is the case 352 */ 353 } 354 355 /* 356 ** If it's not a match, then replace the data. 357 ** Note: this purges the history of a colliding entry, 358 ** which may cause "overruns", i.e., if two entries are 359 ** "cancelling" each other out, then they may exceed 360 ** the limits that are set. This might be mitigated a bit 361 ** by the above "best of 5" function however. 362 ** 363 ** Alternative approach: just use the old data, which may 364 ** cause false positives however. 365 ** To activate this, change deactivate following memset call. 366 */ 367 368 if (coll) 369 { 370 #if NETINET 371 if (saddr->sa.sa_family == AF_INET) 372 { 373 chBest->ch_Family = AF_INET; 374 chBest->ch_Addr4 = saddr->sin.sin_addr; 375 } 376 #endif /* NETINET */ 377 #if NETINET6 378 if (saddr->sa.sa_family == AF_INET6) 379 { 380 chBest->ch_Family = AF_INET6; 381 chBest->ch_Addr6 = saddr->sin6.sin6_addr; 382 } 383 #endif /* NETINET6 */ 384 #if 1 385 memset(chBest->ch_Times, '\0', 386 sizeof(chBest->ch_Times)); 387 #endif /* 1 */ 388 } 389 390 chBest->ch_LTime = now; 391 { 392 CTime_T *ct = &chBest->ch_Times[ticks % CHTSIZE]; 393 394 if (ct->ct_Ticks != ticks) 395 { 396 ct->ct_Ticks = ticks; 397 ct->ct_Count = 0; 398 } 399 ++ct->ct_Count; 400 } 401 } 402 403 /* Now let's count connections on the window */ 404 for (i = 0; i < CHTSIZE; ++i) 405 { 406 CTime_T *ct = &chBest->ch_Times[i]; 407 408 if (ct->ct_Ticks <= ticks && ct->ct_Ticks >= ticks - CHTSIZE) 409 cnt += ct->ct_Count; 410 } 411 412 #if RATECTL_DEBUG 413 sm_syslog(LOG_WARNING, NOQID, 414 "cln: cnt=(%d), CHTSIZE=(%d), ChtGran=(%d)", 415 cnt, CHTSIZE, ChtGran); 416 #endif /* RATECTL_DEBUG */ 417 return cnt; 418 } 419 420 /* 421 ** TOTAL_RATE - Evaluate global connection rate 422 ** 423 ** Parameters: 424 ** now - current time in secs 425 ** update - update data / check only 426 ** 427 ** Returns: 428 ** connection rate (connections / ConnectionRateWindowSize) 429 */ 430 431 static CTime_T srv_Times[CHTSIZE]; 432 static bool srv_Times_OK = false; 433 434 static int 435 total_rate(now, update) 436 time_t now; 437 bool update; 438 { 439 int i; 440 int cnt = 0; 441 CTime_T *ct; 442 unsigned int ticks; 443 444 if (ChtGran < 0) 445 ChtGran = ConnectionRateWindowSize / CHTSIZE; 446 if (ChtGran == 0) 447 ChtGran = 10; 448 ticks = now / ChtGran; 449 if (!srv_Times_OK) 450 { 451 memset(srv_Times, 0, sizeof(srv_Times)); 452 srv_Times_OK = true; 453 } 454 455 /* Let's update data */ 456 if (update) 457 { 458 ct = &srv_Times[ticks % CHTSIZE]; 459 460 if (ct->ct_Ticks != ticks) 461 { 462 ct->ct_Ticks = ticks; 463 ct->ct_Count = 0; 464 } 465 ++ct->ct_Count; 466 } 467 468 /* Let's count connections on the window */ 469 for (i = 0; i < CHTSIZE; ++i) 470 { 471 ct = &srv_Times[i]; 472 473 if (ct->ct_Ticks <= ticks && ct->ct_Ticks >= ticks - CHTSIZE) 474 cnt += ct->ct_Count; 475 } 476 477 #if RATECTL_DEBUG 478 sm_syslog(LOG_WARNING, NOQID, 479 "srv: cnt=(%d), CHTSIZE=(%d), ChtGran=(%d)", 480 cnt, CHTSIZE, ChtGran); 481 #endif /* RATECTL_DEBUG */ 482 483 return cnt; 484 } 485