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+/*
+ * Copyright (c) 2003 Sendmail, Inc. and its suppliers.
+ * All rights reserved.
+ *
+ * By using this file, you agree to the terms and conditions set
+ * forth in the LICENSE file which can be found at the top level of
+ * the sendmail distribution.
+ *
+ * Contributed by Jose Marcio Martins da Cruz - Ecole des Mines de Paris
+ * Jose-Marcio.Martins@ensmp.fr
+ */
+
+/* a part of this code is based on inetd.c for which this copyright applies: */
+/*
+ * Copyright (c) 1983, 1991, 1993, 1994
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sendmail.h>
+SM_RCSID("@(#)$Id: ratectrl.c,v 8.13 2009/05/05 23:19:34 ca Exp $")
+
+/*
+** stuff included - given some warnings (inet_ntoa)
+** - surely not everything is needed
+*/
+
+#if NETINET || NETINET6
+# include <arpa/inet.h>
+#endif /* NETINET || NETINET6 */
+
+#include <sm/time.h>
+
+#ifndef HASH_ALG
+# define HASH_ALG 2
+#endif /* HASH_ALG */
+
+#ifndef RATECTL_DEBUG
+# define RATECTL_DEBUG 0
+#endif /* RATECTL_DEBUG */
+
+/* forward declarations */
+static int client_rate __P((time_t, SOCKADDR *, bool));
+static int total_rate __P((time_t, bool));
+
+/*
+** CONNECTION_RATE_CHECK - updates connection history data
+** and computes connection rate for the given host
+**
+** Parameters:
+** hostaddr -- ip address of smtp client
+** e -- envelope
+**
+** Returns:
+** true (always)
+**
+** Side Effects:
+** updates connection history
+**
+** Warnings:
+** For each connection, this call shall be
+** done only once with the value true for the
+** update parameter.
+** Typically, this call is done with the value
+** true by the father, and once again with
+** the value false by the children.
+**
+*/
+
+bool
+connection_rate_check(hostaddr, e)
+ SOCKADDR *hostaddr;
+ ENVELOPE *e;
+{
+ time_t now;
+ int totalrate, clientrate;
+ static int clientconn = 0;
+
+ now = time(NULL);
+#if RATECTL_DEBUG
+ sm_syslog(LOG_INFO, NOQID, "connection_rate_check entering...");
+#endif /* RATECTL_DEBUG */
+
+ /* update server connection rate */
+ totalrate = total_rate(now, e == NULL);
+#if RATECTL_DEBUG
+ sm_syslog(LOG_INFO, NOQID, "global connection rate: %d", totalrate);
+#endif /* RATECTL_DEBUG */
+
+ /* update client connection rate */
+ clientrate = client_rate(now, hostaddr, e == NULL);
+
+ if (e == NULL)
+ clientconn = count_open_connections(hostaddr);
+
+ if (e != NULL)
+ {
+ char s[16];
+
+ sm_snprintf(s, sizeof(s), "%d", clientrate);
+ macdefine(&e->e_macro, A_TEMP, macid("{client_rate}"), s);
+ sm_snprintf(s, sizeof(s), "%d", totalrate);
+ macdefine(&e->e_macro, A_TEMP, macid("{total_rate}"), s);
+ sm_snprintf(s, sizeof(s), "%d", clientconn);
+ macdefine(&e->e_macro, A_TEMP, macid("{client_connections}"),
+ s);
+ }
+ return true;
+}
+
+/*
+** Data declarations needed to evaluate connection rate
+*/
+
+static int CollTime = 60;
+
+/* this should be a power of 2, otherwise CPMHMASK doesn't work well */
+#ifndef CPMHSIZE
+# define CPMHSIZE 1024
+#endif /* CPMHSIZE */
+
+#define CPMHMASK (CPMHSIZE-1)
+
+#ifndef MAX_CT_STEPS
+# define MAX_CT_STEPS 10
+#endif /* MAX_CT_STEPS */
+
+/*
+** time granularity: 10s (that's one "tick")
+** will be initialised to ConnectionRateWindowSize/CHTSIZE
+** before being used the first time
+*/
+
+static int ChtGran = -1;
+
+#define CHTSIZE 6
+
+/* Number of connections for a certain "tick" */
+typedef struct CTime
+{
+ unsigned long ct_Ticks;
+ int ct_Count;
+}
+CTime_T;
+
+typedef struct CHash
+{
+#if NETINET6 && NETINET
+ union
+ {
+ struct in_addr c4_Addr;
+ struct in6_addr c6_Addr;
+ } cu_Addr;
+# define ch_Addr4 cu_Addr.c4_Addr
+# define ch_Addr6 cu_Addr.c6_Addr
+#else /* NETINET6 && NETINET */
+# if NETINET6
+ struct in6_addr ch_Addr;
+# define ch_Addr6 ch_Addr
+# else /* NETINET6 */
+ struct in_addr ch_Addr;
+# define ch_Addr4 ch_Addr
+# endif /* NETINET6 */
+#endif /* NETINET6 && NETINET */
+
+ int ch_Family;
+ time_t ch_LTime;
+ unsigned long ch_colls;
+
+ /* 6 buckets for ticks: 60s */
+ CTime_T ch_Times[CHTSIZE];
+}
+CHash_T;
+
+static CHash_T CHashAry[CPMHSIZE];
+static bool CHashAryOK = false;
+
+/*
+** CLIENT_RATE - Evaluate connection rate per smtp client
+**
+** Parameters:
+** now - current time in secs
+** saddr - client address
+** update - update data / check only
+**
+** Returns:
+** connection rate (connections / ConnectionRateWindowSize)
+**
+** Side effects:
+** update static global data
+**
+*/
+
+static int
+client_rate(now, saddr, update)
+ time_t now;
+ SOCKADDR *saddr;
+ bool update;
+{
+ unsigned int hv;
+ int i;
+ int cnt;
+ bool coll;
+ CHash_T *chBest = NULL;
+ unsigned int ticks;
+
+ cnt = 0;
+ hv = 0xABC3D20F;
+ if (ChtGran < 0)
+ ChtGran = ConnectionRateWindowSize / CHTSIZE;
+ if (ChtGran <= 0)
+ ChtGran = 10;
+
+ ticks = now / ChtGran;
+
+ if (!CHashAryOK)
+ {
+ memset(CHashAry, 0, sizeof(CHashAry));
+ CHashAryOK = true;
+ }
+
+ {
+ char *p;
+ int addrlen;
+#if HASH_ALG != 1
+ int c, d;
+#endif /* HASH_ALG != 1 */
+
+ switch (saddr->sa.sa_family)
+ {
+#if NETINET
+ case AF_INET:
+ p = (char *)&saddr->sin.sin_addr;
+ addrlen = sizeof(struct in_addr);
+ break;
+#endif /* NETINET */
+#if NETINET6
+ case AF_INET6:
+ p = (char *)&saddr->sin6.sin6_addr;
+ addrlen = sizeof(struct in6_addr);
+ break;
+#endif /* NETINET6 */
+ default:
+ /* should not happen */
+ return -1;
+ }
+
+ /* compute hash value */
+ for (i = 0; i < addrlen; ++i, ++p)
+#if HASH_ALG == 1
+ hv = (hv << 5) ^ (hv >> 23) ^ *p;
+ hv = (hv ^ (hv >> 16));
+#elif HASH_ALG == 2
+ {
+ d = *p;
+ c = d;
+ c ^= c<<6;
+ hv += (c<<11) ^ (c>>1);
+ hv ^= (d<<14) + (d<<7) + (d<<4) + d;
+ }
+#elif HASH_ALG == 3
+ {
+ hv = (hv << 4) + *p;
+ d = hv & 0xf0000000;
+ if (d != 0)
+ {
+ hv ^= (d >> 24);
+ hv ^= d;
+ }
+ }
+#else /* HASH_ALG == 1 */
+ hv = ((hv << 1) ^ (*p & 0377)) % cctx->cc_size;
+#endif /* HASH_ALG == 1 */
+ }
+
+ coll = true;
+ for (i = 0; i < MAX_CT_STEPS; ++i)
+ {
+ CHash_T *ch = &CHashAry[(hv + i) & CPMHMASK];
+
+#if NETINET
+ if (saddr->sa.sa_family == AF_INET &&
+ ch->ch_Family == AF_INET &&
+ (saddr->sin.sin_addr.s_addr == ch->ch_Addr4.s_addr ||
+ ch->ch_Addr4.s_addr == 0))
+ {
+ chBest = ch;
+ coll = false;
+ break;
+ }
+#endif /* NETINET */
+#if NETINET6
+ if (saddr->sa.sa_family == AF_INET6 &&
+ ch->ch_Family == AF_INET6 &&
+ (IN6_ARE_ADDR_EQUAL(&saddr->sin6.sin6_addr,
+ &ch->ch_Addr6) != 0 ||
+ IN6_IS_ADDR_UNSPECIFIED(&ch->ch_Addr6)))
+ {
+ chBest = ch;
+ coll = false;
+ break;
+ }
+#endif /* NETINET6 */
+ if (chBest == NULL || ch->ch_LTime == 0 ||
+ ch->ch_LTime < chBest->ch_LTime)
+ chBest = ch;
+ }
+
+ /* Let's update data... */
+ if (update)
+ {
+ if (coll && (now - chBest->ch_LTime < CollTime))
+ {
+ /*
+ ** increment the number of collisions last
+ ** CollTime for this client
+ */
+
+ chBest->ch_colls++;
+
+ /*
+ ** Maybe shall log if collision rate is too high...
+ ** and take measures to resize tables
+ ** if this is the case
+ */
+ }
+
+ /*
+ ** If it's not a match, then replace the data.
+ ** Note: this purges the history of a colliding entry,
+ ** which may cause "overruns", i.e., if two entries are
+ ** "cancelling" each other out, then they may exceed
+ ** the limits that are set. This might be mitigated a bit
+ ** by the above "best of 5" function however.
+ **
+ ** Alternative approach: just use the old data, which may
+ ** cause false positives however.
+ ** To activate this, change deactivate following memset call.
+ */
+
+ if (coll)
+ {
+#if NETINET
+ if (saddr->sa.sa_family == AF_INET)
+ {
+ chBest->ch_Family = AF_INET;
+ chBest->ch_Addr4 = saddr->sin.sin_addr;
+ }
+#endif /* NETINET */
+#if NETINET6
+ if (saddr->sa.sa_family == AF_INET6)
+ {
+ chBest->ch_Family = AF_INET6;
+ chBest->ch_Addr6 = saddr->sin6.sin6_addr;
+ }
+#endif /* NETINET6 */
+#if 1
+ memset(chBest->ch_Times, '\0',
+ sizeof(chBest->ch_Times));
+#endif /* 1 */
+ }
+
+ chBest->ch_LTime = now;
+ {
+ CTime_T *ct = &chBest->ch_Times[ticks % CHTSIZE];
+
+ if (ct->ct_Ticks != ticks)
+ {
+ ct->ct_Ticks = ticks;
+ ct->ct_Count = 0;
+ }
+ ++ct->ct_Count;
+ }
+ }
+
+ /* Now let's count connections on the window */
+ for (i = 0; i < CHTSIZE; ++i)
+ {
+ CTime_T *ct = &chBest->ch_Times[i];
+
+ if (ct->ct_Ticks <= ticks && ct->ct_Ticks >= ticks - CHTSIZE)
+ cnt += ct->ct_Count;
+ }
+
+#if RATECTL_DEBUG
+ sm_syslog(LOG_WARNING, NOQID,
+ "cln: cnt=(%d), CHTSIZE=(%d), ChtGran=(%d)",
+ cnt, CHTSIZE, ChtGran);
+#endif /* RATECTL_DEBUG */
+ return cnt;
+}
+
+/*
+** TOTAL_RATE - Evaluate global connection rate
+**
+** Parameters:
+** now - current time in secs
+** update - update data / check only
+**
+** Returns:
+** connection rate (connections / ConnectionRateWindowSize)
+*/
+
+static CTime_T srv_Times[CHTSIZE];
+static bool srv_Times_OK = false;
+
+static int
+total_rate(now, update)
+ time_t now;
+ bool update;
+{
+ int i;
+ int cnt = 0;
+ CTime_T *ct;
+ unsigned int ticks;
+
+ if (ChtGran < 0)
+ ChtGran = ConnectionRateWindowSize / CHTSIZE;
+ if (ChtGran == 0)
+ ChtGran = 10;
+ ticks = now / ChtGran;
+ if (!srv_Times_OK)
+ {
+ memset(srv_Times, 0, sizeof(srv_Times));
+ srv_Times_OK = true;
+ }
+
+ /* Let's update data */
+ if (update)
+ {
+ ct = &srv_Times[ticks % CHTSIZE];
+
+ if (ct->ct_Ticks != ticks)
+ {
+ ct->ct_Ticks = ticks;
+ ct->ct_Count = 0;
+ }
+ ++ct->ct_Count;
+ }
+
+ /* Let's count connections on the window */
+ for (i = 0; i < CHTSIZE; ++i)
+ {
+ ct = &srv_Times[i];
+
+ if (ct->ct_Ticks <= ticks && ct->ct_Ticks >= ticks - CHTSIZE)
+ cnt += ct->ct_Count;
+ }
+
+#if RATECTL_DEBUG
+ sm_syslog(LOG_WARNING, NOQID,
+ "srv: cnt=(%d), CHTSIZE=(%d), ChtGran=(%d)",
+ cnt, CHTSIZE, ChtGran);
+#endif /* RATECTL_DEBUG */
+
+ return cnt;
+}
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