moved net module to runtime

after careful analysis, I concluded that it is OK to
place the current net.c/.h code under LGPL. Individual
contributor agreement is given and no sysklogd code
remains (see net.c for details).

1 files changed, 1149 insertions, 0 deletions

diff --git a/runtime/net.c b/runtime/net.c
new file mode 100644
index 00000000..84c286d2
--- /dev/null
+++ b/runtime/net.c
@@ -0,0 +1,1149 @@
+/* net.c
+ * Implementation of network-related stuff.
+ *
+ * File begun on 2007-07-20 by RGerhards (extracted from syslogd.c)
+ * This file is under development and has not yet arrived at being fully
+ * self-contained and a real object. So far, it is mostly an excerpt
+ * of the "old" message code without any modifications. However, it
+ * helps to have things at the right place one we go to the meat of it.
+ *
+ * Starting 2007-12-24, I have begun to shuffle more network-related code
+ * from syslogd.c to over here. I am not sure if it will stay here in the
+ * long term, but it is good to have it out of syslogd.c. Maybe this here is
+ * an interim location ;)
+ *
+ * Copyright 2007, 2008 Rainer Gerhards and Adiscon GmbH.
+ *
+ * rgerhards, 2008-04-16: I changed this code to LGPL today. I carefully analyzed
+ * that it does not borrow code from the original sysklogd and that I have 
+ * permission to do so from all other contributors. My analysis found that all
+ * code from sysklogd has been superseeded by our own functionality, so it 
+ * is OK to move this file to LGPL. Some variable sysklogd variable names
+ * remain, but even this will change as the net object evolves.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * The rsyslog runtime library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The rsyslog runtime library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the rsyslog runtime library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
+ */
+#include "config.h"
+
+#include "rsyslog.h"
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <signal.h>
+#include <ctype.h>
+#include <netdb.h>
+#include <fnmatch.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "syslogd.h"
+#include "syslogd-types.h"
+#include "module-template.h"
+#include "parse.h"
+#include "srUtils.h"
+#include "obj.h"
+#include "errmsg.h"
+#include "net.h"
+
+MODULE_TYPE_LIB
+
+/* static data */
+DEFobjStaticHelpers
+DEFobjCurrIf(errmsg)
+
+/* support for defining allowed TCP and UDP senders. We use the same
+ * structure to implement this (a linked list), but we define two different
+ * list roots, one for UDP and one for TCP.
+ * rgerhards, 2005-09-26
+ */
+/* All of the five below are read-only after startup */
+struct AllowedSenders *pAllowedSenders_UDP = NULL; /* the roots of the allowed sender */
+struct AllowedSenders *pAllowedSenders_TCP = NULL; /* lists. If NULL, all senders are ok! */
+static struct AllowedSenders *pLastAllowedSenders_UDP = NULL; /* and now the pointers to the last */
+static struct AllowedSenders *pLastAllowedSenders_TCP = NULL; /* element in the respective list */
+#ifdef USE_GSSAPI
+struct AllowedSenders *pAllowedSenders_GSS = NULL;
+static struct AllowedSenders *pLastAllowedSenders_GSS = NULL;
+#endif
+
+int     ACLAddHostnameOnFail = 0; /* add hostname to acl when DNS resolving has failed */
+int     ACLDontResolve = 0;       /* add hostname to acl instead of resolving it to IP(s) */
+
+/* Code for handling allowed/disallowed senders
+ */
+static inline void MaskIP6 (struct in6_addr *addr, uint8_t bits) {
+	register uint8_t i;
+	
+	assert (addr != NULL);
+	assert (bits <= 128);
+	
+	i = bits/32;
+	if (bits%32)
+		addr->s6_addr32[i++] &= htonl(0xffffffff << (32 - (bits % 32)));
+	for (; i < (sizeof addr->s6_addr32)/4; i++)
+		addr->s6_addr32[i] = 0;
+}
+
+static inline void MaskIP4 (struct in_addr  *addr, uint8_t bits) {
+	
+	assert (addr != NULL);
+	assert (bits <=32 );
+	
+	addr->s_addr &= htonl(0xffffffff << (32 - bits));
+}
+
+#define SIN(sa)  ((struct sockaddr_in  *)(sa))
+#define SIN6(sa) ((struct sockaddr_in6 *)(sa))
+
+/* This function adds an allowed sender entry to the ACL linked list.
+ * In any case, a single entry is added. If an error occurs, the
+ * function does its error reporting itself. All validity checks
+ * must already have been done by the caller.
+ * This is a helper to AddAllowedSender().
+ * rgerhards, 2007-07-17
+ */
+static rsRetVal AddAllowedSenderEntry(struct AllowedSenders **ppRoot, struct AllowedSenders **ppLast,
+		     		      struct NetAddr *iAllow, uint8_t iSignificantBits)
+{
+	struct AllowedSenders *pEntry = NULL;
+
+	assert(ppRoot != NULL);
+	assert(ppLast != NULL);
+	assert(iAllow != NULL);
+
+	if((pEntry = (struct AllowedSenders*) calloc(1, sizeof(struct AllowedSenders))) == NULL) {
+		glblHadMemShortage = 1;
+		return RS_RET_OUT_OF_MEMORY; /* no options left :( */
+	}
+	
+	memcpy(&(pEntry->allowedSender), iAllow, sizeof (struct NetAddr));
+	pEntry->pNext = NULL;
+	pEntry->SignificantBits = iSignificantBits;
+	
+	/* enqueue */
+	if(*ppRoot == NULL) {
+		*ppRoot = pEntry;
+	} else {
+		(*ppLast)->pNext = pEntry;
+	}
+	*ppLast = pEntry;
+	
+	return RS_RET_OK;
+}
+
+/* function to clear the allowed sender structure in cases where
+ * it must be freed (occurs most often when HUPed.
+ * TODO: reconsider recursive implementation
+ * I think there is also a memory leak, because only the last entry
+ * is acutally deleted... -- rgerhards, 2007-12-25
+ */
+void clearAllowedSenders (struct AllowedSenders *pAllow)
+{
+	if (pAllow != NULL) {
+		if (pAllow->pNext != NULL)
+			clearAllowedSenders (pAllow->pNext);
+		else {
+			if (F_ISSET(pAllow->allowedSender.flags, ADDR_NAME))
+				free (pAllow->allowedSender.addr.HostWildcard);
+			else
+				free (pAllow->allowedSender.addr.NetAddr);
+			
+			free (pAllow);
+		}
+	}
+}
+
+/* function to add an allowed sender to the allowed sender list. The
+ * root of the list is caller-provided, so it can be used for all
+ * supported lists. The caller must provide a pointer to the root,
+ * as it eventually needs to be updated. Also, a pointer to the
+ * pointer to the last element must be provided (to speed up adding
+ * list elements).
+ * rgerhards, 2005-09-26
+ * If a hostname is given there are possible multiple entries
+ * added (all addresses from that host).
+ */
+static rsRetVal AddAllowedSender(struct AllowedSenders **ppRoot, struct AllowedSenders **ppLast,
+		     		 struct NetAddr *iAllow, uint8_t iSignificantBits)
+{
+	DEFiRet;
+
+	assert(ppRoot != NULL);
+	assert(ppLast != NULL);
+	assert(iAllow != NULL);
+
+	if (!F_ISSET(iAllow->flags, ADDR_NAME)) {
+		if(iSignificantBits == 0)
+			/* we handle this seperatly just to provide a better
+			 * error message.
+			 */
+			errmsg.LogError(NO_ERRCODE, "You can not specify 0 bits of the netmask, this would "
+				 "match ALL systems. If you really intend to do that, "
+				 "remove all $AllowedSender directives.");
+		
+		switch (iAllow->addr.NetAddr->sa_family) {
+		case AF_INET:
+			if((iSignificantBits < 1) || (iSignificantBits > 32)) {
+				errmsg.LogError(NO_ERRCODE, "Invalid number of bits (%d) in IPv4 address - adjusted to 32",
+					    (int)iSignificantBits);
+				iSignificantBits = 32;
+			}
+			
+			MaskIP4 (&(SIN(iAllow->addr.NetAddr)->sin_addr), iSignificantBits);
+			break;
+		case AF_INET6:
+			if((iSignificantBits < 1) || (iSignificantBits > 128)) {
+				errmsg.LogError(NO_ERRCODE, "Invalid number of bits (%d) in IPv6 address - adjusted to 128",
+					    iSignificantBits);
+				iSignificantBits = 128;
+			}
+
+			MaskIP6 (&(SIN6(iAllow->addr.NetAddr)->sin6_addr), iSignificantBits);
+			break;
+		default:
+			/* rgerhards, 2007-07-16: We have an internal program error in this
+			 * case. However, there is not much we can do against it right now. Of
+			 * course, we could abort, but that would probably cause more harm
+			 * than good. So we continue to run. We simply do not add this line - the
+			 * worst thing that happens is that one host will not be allowed to
+			 * log.
+			 */
+			errmsg.LogError(NO_ERRCODE, "Internal error caused AllowedSender to be ignored, AF = %d",
+				    iAllow->addr.NetAddr->sa_family);
+			ABORT_FINALIZE(RS_RET_ERR);
+		}
+		/* OK, entry constructed, now lets add it to the ACL list */
+		iRet = AddAllowedSenderEntry(ppRoot, ppLast, iAllow, iSignificantBits);
+	} else {
+		/* we need to process a hostname ACL */
+		if (DisableDNS) {
+			errmsg.LogError(NO_ERRCODE, "Ignoring hostname based ACLs because DNS is disabled.");
+			ABORT_FINALIZE(RS_RET_OK);
+		}
+		
+		if (!strchr (iAllow->addr.HostWildcard, '*') &&
+		    !strchr (iAllow->addr.HostWildcard, '?') &&
+		    ACLDontResolve == 0) {
+			/* single host - in this case, we pull its IP addresses from DNS
+			* and add IP-based ACLs.
+			*/
+			struct addrinfo hints, *res, *restmp;
+			struct NetAddr allowIP;
+			
+			memset (&hints, 0, sizeof (struct addrinfo));
+			hints.ai_family = AF_UNSPEC;
+			hints.ai_socktype = SOCK_DGRAM;
+#			ifdef AI_ADDRCONFIG /* seems not to be present on all systems */
+				hints.ai_flags  = AI_ADDRCONFIG;
+#			endif
+
+			if (getaddrinfo (iAllow->addr.HostWildcard, NULL, &hints, &res) != 0) {
+			        errmsg.LogError(NO_ERRCODE, "DNS error: Can't resolve \"%s\"", iAllow->addr.HostWildcard);
+				
+				if (ACLAddHostnameOnFail) {
+				        errmsg.LogError(NO_ERRCODE, "Adding hostname \"%s\" to ACL as a wildcard entry.", iAllow->addr.HostWildcard);
+				        iRet = AddAllowedSenderEntry(ppRoot, ppLast, iAllow, iSignificantBits);
+					FINALIZE;
+				} else {
+				        errmsg.LogError(NO_ERRCODE, "Hostname \"%s\" WON\'T be added to ACL.", iAllow->addr.HostWildcard);
+				        ABORT_FINALIZE(RS_RET_NOENTRY);
+				}
+			}
+			
+			for (restmp = res ; res != NULL ; res = res->ai_next) {
+				switch (res->ai_family) {
+				case AF_INET: /* add IPv4 */
+					iSignificantBits = 32;
+					allowIP.flags = 0;
+					if((allowIP.addr.NetAddr = malloc(res->ai_addrlen)) == NULL) {
+						glblHadMemShortage = 1;
+						ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
+					}
+					memcpy(allowIP.addr.NetAddr, res->ai_addr, res->ai_addrlen);
+					
+					if((iRet = AddAllowedSenderEntry(ppRoot, ppLast, &allowIP, iSignificantBits))
+						!= RS_RET_OK)
+						FINALIZE;
+					break;
+				case AF_INET6: /* IPv6 - but need to check if it is a v6-mapped IPv4 */
+					if(IN6_IS_ADDR_V4MAPPED (&SIN6(res->ai_addr)->sin6_addr)) {
+						/* extract & add IPv4 */
+						
+						iSignificantBits = 32;
+						allowIP.flags = 0;
+						if((allowIP.addr.NetAddr = malloc(sizeof(struct sockaddr_in)))
+						    == NULL) {
+							glblHadMemShortage = 1;
+							ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
+						}
+						SIN(allowIP.addr.NetAddr)->sin_family = AF_INET;
+#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN    
+                                                SIN(allowIP.addr.NetAddr)->sin_len    = sizeof (struct sockaddr_in);
+#endif
+						SIN(allowIP.addr.NetAddr)->sin_port   = 0;
+						memcpy(&(SIN(allowIP.addr.NetAddr)->sin_addr.s_addr),
+							&(SIN6(res->ai_addr)->sin6_addr.s6_addr32[3]),
+							sizeof (struct sockaddr_in));
+
+						if((iRet = AddAllowedSenderEntry(ppRoot, ppLast, &allowIP,
+								iSignificantBits))
+							!= RS_RET_OK)
+							FINALIZE;
+					} else {
+						/* finally add IPv6 */
+						
+						iSignificantBits = 128;
+						allowIP.flags = 0;
+						if((allowIP.addr.NetAddr = malloc(res->ai_addrlen)) == NULL) {
+							glblHadMemShortage = 1;
+							ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
+						}
+						memcpy(allowIP.addr.NetAddr, res->ai_addr, res->ai_addrlen);
+						
+						if((iRet = AddAllowedSenderEntry(ppRoot, ppLast, &allowIP,
+								iSignificantBits))
+							!= RS_RET_OK)
+							FINALIZE;
+					}
+					break;
+				}
+			}
+			freeaddrinfo (restmp);
+		} else {
+			/* wildcards in hostname - we need to add a text-based ACL.
+			 * For this, we already have everything ready and just need
+			 * to pass it along...
+			 */
+			iRet =  AddAllowedSenderEntry(ppRoot, ppLast, iAllow, iSignificantBits);
+		}
+	}
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* Print an allowed sender list. The caller must tell us which one.
+ * iListToPrint = 1 means UDP, 2 means TCP
+ * rgerhards, 2005-09-27
+ */
+void PrintAllowedSenders(int iListToPrint)
+{
+	struct AllowedSenders *pSender;
+	uchar szIP[64];
+	
+	assert((iListToPrint == 1) || (iListToPrint == 2)
+#ifdef USE_GSSAPI
+	       || (iListToPrint == 3)
+#endif
+	       );
+
+	dbgprintf("Allowed %s Senders:\n",
+	       (iListToPrint == 1) ? "UDP" :
+#ifdef USE_GSSAPI
+	       (iListToPrint == 3) ? "GSS" :
+#endif
+	       "TCP");
+
+	pSender = (iListToPrint == 1) ? pAllowedSenders_UDP :
+#ifdef USE_GSSAPI
+		(iListToPrint == 3) ? pAllowedSenders_GSS :
+#endif
+		pAllowedSenders_TCP;
+	if(pSender == NULL) {
+		dbgprintf("\tNo restrictions set.\n");
+	} else {
+		while(pSender != NULL) {
+			if (F_ISSET(pSender->allowedSender.flags, ADDR_NAME))
+				dbgprintf ("\t%s\n", pSender->allowedSender.addr.HostWildcard);
+			else {
+				if(getnameinfo (pSender->allowedSender.addr.NetAddr,
+						     SALEN(pSender->allowedSender.addr.NetAddr),
+						     (char*)szIP, 64, NULL, 0, NI_NUMERICHOST) == 0) {
+					dbgprintf ("\t%s/%u\n", szIP, pSender->SignificantBits);
+				} else {
+					/* getnameinfo() failed - but as this is only a
+					 * debug function, we simply spit out an error and do
+					 * not care much about it.
+					 */
+					dbgprintf("\tERROR in getnameinfo() - something may be wrong "
+						"- ignored for now\n");
+				}
+			}
+			pSender = pSender->pNext;
+		}
+	}
+}
+
+
+/* parse an allowed sender config line and add the allowed senders
+ * (if the line is correct).
+ * rgerhards, 2005-09-27
+ */
+rsRetVal addAllowedSenderLine(char* pName, uchar** ppRestOfConfLine)
+{
+	struct AllowedSenders **ppRoot;
+	struct AllowedSenders **ppLast;
+	rsParsObj *pPars;
+	rsRetVal iRet;
+	struct NetAddr *uIP = NULL;
+	int iBits;
+
+	assert(pName != NULL);
+	assert(ppRestOfConfLine != NULL);
+	assert(*ppRestOfConfLine != NULL);
+
+	if(!strcasecmp(pName, "udp")) {
+		ppRoot = &pAllowedSenders_UDP;
+		ppLast = &pLastAllowedSenders_UDP;
+	} else if(!strcasecmp(pName, "tcp")) {
+		ppRoot = &pAllowedSenders_TCP;
+		ppLast = &pLastAllowedSenders_TCP;
+#ifdef USE_GSSAPI
+	} else if(!strcasecmp(pName, "gss")) {
+		ppRoot = &pAllowedSenders_GSS;
+		ppLast = &pLastAllowedSenders_GSS;
+#endif
+	} else {
+		errmsg.LogError(NO_ERRCODE, "Invalid protocol '%s' in allowed sender "
+		           "list, line ignored", pName);
+		return RS_RET_ERR;
+	}
+
+	/* OK, we now know the protocol and have valid list pointers.
+	 * So let's process the entries. We are using the parse class
+	 * for this.
+	 */
+	/* create parser object starting with line string without leading colon */
+	if((iRet = rsParsConstructFromSz(&pPars, (uchar*) *ppRestOfConfLine) != RS_RET_OK)) {
+		errmsg.LogError(NO_ERRCODE, "Error %d constructing parser object - ignoring allowed sender list", iRet);
+		return(iRet);
+	}
+
+	while(!parsIsAtEndOfParseString(pPars)) {
+		if(parsPeekAtCharAtParsPtr(pPars) == '#')
+			break; /* a comment-sign stops processing of line */
+		/* now parse a single IP address */
+		if((iRet = parsAddrWithBits(pPars, &uIP, &iBits)) != RS_RET_OK) {
+			errmsg.LogError(NO_ERRCODE, "Error %d parsing address in allowed sender"
+				    "list - ignoring.", iRet);
+			rsParsDestruct(pPars);
+			return(iRet);
+		}
+		if((iRet = AddAllowedSender(ppRoot, ppLast, uIP, iBits))
+			!= RS_RET_OK) {
+		        if (iRet == RS_RET_NOENTRY) {
+			        errmsg.LogError(NO_ERRCODE, "Error %d adding allowed sender entry "
+					    "- ignoring.", iRet);
+		        } else {
+			        errmsg.LogError(NO_ERRCODE, "Error %d adding allowed sender entry "
+					    "- terminating, nothing more will be added.", iRet);
+				rsParsDestruct(pPars);
+				return(iRet);
+		        }
+		}
+		free (uIP); /* copy stored in AllowedSenders list */ 
+	}
+
+	/* cleanup */
+	*ppRestOfConfLine += parsGetCurrentPosition(pPars);
+	return rsParsDestruct(pPars);
+}
+
+
+
+/* compares a host to an allowed sender list entry. Handles all subleties
+ * including IPv4/v6 as well as domain name wildcards.
+ * This is a helper to isAllowedSender. As it is only called once, it is
+ * declared inline.
+ * Returns 0 if they do not match, something else otherwise.
+ * contributed 1007-07-16 by mildew@gmail.com
+ */
+static inline int MaskCmp(struct NetAddr *pAllow, uint8_t bits, struct sockaddr *pFrom, const char *pszFromHost)
+{
+	assert(pAllow != NULL);
+	assert(pFrom != NULL);
+
+	if(F_ISSET(pAllow->flags, ADDR_NAME)) {
+		dbgprintf("MaskCmp: host=\"%s\"; pattern=\"%s\"\n", pszFromHost, pAllow->addr.HostWildcard);
+		
+#		if !defined(FNM_CASEFOLD)
+			/* TODO: I don't know if that then works, seen on HP UX, what I have not in lab... ;) */
+			return(fnmatch(pAllow->addr.HostWildcard, pszFromHost, FNM_NOESCAPE) == 0);
+#		else
+			return(fnmatch(pAllow->addr.HostWildcard, pszFromHost, FNM_NOESCAPE|FNM_CASEFOLD) == 0);
+#		endif
+	} else {/* We need to compare an IP address */
+		switch (pFrom->sa_family) {
+		case AF_INET:
+			if (AF_INET == pAllow->addr.NetAddr->sa_family)
+				return(( SIN(pFrom)->sin_addr.s_addr & htonl(0xffffffff << (32 - bits)) )
+				       == SIN(pAllow->addr.NetAddr)->sin_addr.s_addr);
+			else
+				return 0;
+			break;
+		case AF_INET6:
+			switch (pAllow->addr.NetAddr->sa_family) {
+			case AF_INET6: {
+				struct in6_addr ip, net;
+				register uint8_t i;
+				
+				memcpy (&ip,  &(SIN6(pFrom))->sin6_addr, sizeof (struct in6_addr));
+				memcpy (&net, &(SIN6(pAllow->addr.NetAddr))->sin6_addr, sizeof (struct in6_addr));
+				
+				i = bits/32;
+				if (bits % 32)
+					ip.s6_addr32[i++] &= htonl(0xffffffff << (32 - (bits % 32)));
+				for (; i < (sizeof ip.s6_addr32)/4; i++)
+					ip.s6_addr32[i] = 0;
+				
+				return (memcmp (ip.s6_addr, net.s6_addr, sizeof ip.s6_addr) == 0 &&
+					(SIN6(pAllow->addr.NetAddr)->sin6_scope_id != 0 ?
+					 SIN6(pFrom)->sin6_scope_id == SIN6(pAllow->addr.NetAddr)->sin6_scope_id : 1));
+			}
+			case AF_INET: {
+				struct in6_addr *ip6 = &(SIN6(pFrom))->sin6_addr;
+				struct in_addr  *net = &(SIN(pAllow->addr.NetAddr))->sin_addr;
+				
+				if ((ip6->s6_addr32[3] & (u_int32_t) htonl((0xffffffff << (32 - bits)))) == net->s_addr &&
+#if BYTE_ORDER == LITTLE_ENDIAN
+				    (ip6->s6_addr32[2] == (u_int32_t)0xffff0000) &&
+#else
+				    (ip6->s6_addr32[2] == (u_int32_t)0x0000ffff) &&
+#endif
+				    (ip6->s6_addr32[1] == 0) && (ip6->s6_addr32[0] == 0))
+					return 1;
+				else
+					return 0;
+			}
+			default:
+				/* Unsupported AF */
+				return 0;
+			}
+		default:
+			/* Unsupported AF */
+			return 0;
+		}
+	}
+}
+
+
+/* check if a sender is allowed. The root of the the allowed sender.
+ * list must be proveded by the caller. As such, this function can be
+ * used to check both UDP and TCP allowed sender lists.
+ * returns 1, if the sender is allowed, 0 otherwise.
+ * rgerhards, 2005-09-26
+ */
+static int isAllowedSender(struct AllowedSenders *pAllowRoot, struct sockaddr *pFrom, const char *pszFromHost)
+{
+	struct AllowedSenders *pAllow;
+	
+	assert(pFrom != NULL);
+
+	if(pAllowRoot == NULL)
+		return 1; /* checking disabled, everything is valid! */
+	
+	/* now we loop through the list of allowed senders. As soon as
+	 * we find a match, we return back (indicating allowed). We loop
+	 * until we are out of allowed senders. If so, we fall through the
+	 * loop and the function's terminal return statement will indicate
+	 * that the sender is disallowed.
+	 */
+	for(pAllow = pAllowRoot ; pAllow != NULL ; pAllow = pAllow->pNext) {
+		if (MaskCmp (&(pAllow->allowedSender), pAllow->SignificantBits, pFrom, pszFromHost))
+			return 1;
+	}
+	return 0;
+}
+
+
+/* The following #ifdef sequence is a small compatibility 
+ * layer. It tries to work around the different availality
+ * levels of SO_BSDCOMPAT on linuxes...
+ * I borrowed this code from
+ *    http://www.erlang.org/ml-archive/erlang-questions/200307/msg00037.html
+ * It still needs to be a bit better adapted to rsyslog.
+ * rgerhards 2005-09-19
+ */
+#include <sys/utsname.h>
+static int
+should_use_so_bsdcompat(void)
+{
+#ifndef OS_BSD
+    static int init_done;
+    static int so_bsdcompat_is_obsolete;
+
+    if (!init_done) {
+	struct utsname myutsname;
+	unsigned int version, patchlevel;
+
+	init_done = 1;
+	if (uname(&myutsname) < 0) {
+		char errStr[1024];
+		dbgprintf("uname: %s\r\n", rs_strerror_r(errno, errStr, sizeof(errStr)));
+		return 1;
+	}
+	/* Format is <version>.<patchlevel>.<sublevel><extraversion>
+	   where the first three are unsigned integers and the last
+	   is an arbitrary string. We only care about the first two. */
+	if (sscanf(myutsname.release, "%u.%u", &version, &patchlevel) != 2) {
+	    dbgprintf("uname: unexpected release '%s'\r\n",
+		    myutsname.release);
+	    return 1;
+	}
+	/* SO_BSCOMPAT is deprecated and triggers warnings in 2.5
+	   kernels. It is a no-op in 2.4 but not in 2.2 kernels. */
+	if (version > 2 || (version == 2 && patchlevel >= 5))
+	    so_bsdcompat_is_obsolete = 1;
+    }
+    return !so_bsdcompat_is_obsolete;
+#else	/* #ifndef OS_BSD */
+    return 1;
+#endif	/* #ifndef OS_BSD */
+}
+#ifndef SO_BSDCOMPAT
+/* this shall prevent compiler errors due to undfined name */
+#define SO_BSDCOMPAT 0
+#endif
+
+
+/* get the hostname of the message source. This was originally in cvthname()
+ * but has been moved out of it because of clarity and fuctional separation.
+ * It must be provided by the socket we received the message on as well as
+ * a NI_MAXHOST size large character buffer for the FQDN.
+ *
+ * Please see http://www.hmug.org/man/3/getnameinfo.php (under Caveats)
+ * for some explanation of the code found below. We do by default not
+ * discard message where we detected malicouos DNS PTR records. However,
+ * there is a user-configurabel option that will tell us if
+ * we should abort. For this, the return value tells the caller if the
+ * message should be processed (1) or discarded (0).
+ */
+static rsRetVal
+gethname(struct sockaddr_storage *f, uchar *pszHostFQDN)
+{
+	DEFiRet;
+	int error;
+	sigset_t omask, nmask;
+	char ip[NI_MAXHOST];
+	struct addrinfo hints, *res;
+	
+	assert(f != NULL);
+	assert(pszHostFQDN != NULL);
+
+        error = getnameinfo((struct sockaddr *)f, SALEN((struct sockaddr *)f),
+			    ip, sizeof ip, NULL, 0, NI_NUMERICHOST);
+
+        if (error) {
+                dbgprintf("Malformed from address %s\n", gai_strerror(error));
+		strcpy((char*) pszHostFQDN, "???");
+		ABORT_FINALIZE(RS_RET_INVALID_SOURCE);
+	}
+
+	if (!DisableDNS) {
+		sigemptyset(&nmask);
+		sigaddset(&nmask, SIGHUP);
+		pthread_sigmask(SIG_BLOCK, &nmask, &omask);
+
+		error = getnameinfo((struct sockaddr *)f, SALEN((struct sockaddr *) f),
+				    (char*)pszHostFQDN, NI_MAXHOST, NULL, 0, NI_NAMEREQD);
+		
+		if (error == 0) {
+			memset (&hints, 0, sizeof (struct addrinfo));
+			hints.ai_flags = AI_NUMERICHOST;
+			hints.ai_socktype = SOCK_DGRAM;
+
+			/* we now do a lookup once again. This one should fail,
+			 * because we should not have obtained a non-numeric address. If
+			 * we got a numeric one, someone messed with DNS!
+			 */
+			if (getaddrinfo ((char*)pszHostFQDN, NULL, &hints, &res) == 0) {
+				uchar szErrMsg[1024];
+				freeaddrinfo (res);
+				/* OK, we know we have evil. The question now is what to do about
+				 * it. One the one hand, the message might probably be intended
+				 * to harm us. On the other hand, losing the message may also harm us.
+				 * Thus, the behaviour is controlled by the $DropMsgsWithMaliciousDnsPTRRecords
+				 * option. If it tells us we should discard, we do so, else we proceed,
+				 * but log an error message together with it.
+				 * time being, we simply drop the name we obtained and use the IP - that one
+				 * is OK in any way. We do also log the error message. rgerhards, 2007-07-16
+		 		 */
+		 		if(bDropMalPTRMsgs == 1) {
+					snprintf((char*)szErrMsg, sizeof(szErrMsg) / sizeof(uchar),
+						 "Malicious PTR record, message dropped "
+						 "IP = \"%s\" HOST = \"%s\"",
+						 ip, pszHostFQDN);
+					errmsg.LogError(NO_ERRCODE, "%s", szErrMsg);
+					pthread_sigmask(SIG_SETMASK, &omask, NULL);
+					ABORT_FINALIZE(RS_RET_MALICIOUS_ENTITY);
+				}
+
+				/* Please note: we deal with a malicous entry. Thus, we have crafted
+				 * the snprintf() below so that all text is in front of the entry - maybe
+				 * it contains characters that make the message unreadable
+				 * (OK, I admit this is more or less impossible, but I am paranoid...)
+				 * rgerhards, 2007-07-16
+				 */
+				snprintf((char*)szErrMsg, sizeof(szErrMsg) / sizeof(uchar),
+					 "Malicious PTR record (message accepted, but used IP "
+					 "instead of PTR name: IP = \"%s\" HOST = \"%s\"",
+					 ip, pszHostFQDN);
+				errmsg.LogError(NO_ERRCODE, "%s", szErrMsg);
+
+				error = 1; /* that will trigger using IP address below. */
+			}
+		}		
+		pthread_sigmask(SIG_SETMASK, &omask, NULL);
+	}
+
+        if (error || DisableDNS) {
+                dbgprintf("Host name for your address (%s) unknown\n", ip);
+		strcpy((char*) pszHostFQDN, ip);
+		ABORT_FINALIZE(RS_RET_ADDRESS_UNKNOWN);
+        }
+
+finalize_it:
+	RETiRet;
+}
+
+
+
+/* print out which socket we are listening on. This is only
+ * a debug aid. rgerhards, 2007-07-02
+ */
+void debugListenInfo(int fd, char *type)
+{
+	char *szFamily;
+	int port;
+	struct sockaddr sa;
+	struct sockaddr_in *ipv4;
+	struct sockaddr_in6 *ipv6;
+	socklen_t saLen = sizeof(sa);
+
+	if(getsockname(fd, &sa, &saLen) == 0) {
+		switch(sa.sa_family) {
+		case PF_INET:
+			szFamily = "IPv4";
+			ipv4 = (struct sockaddr_in*) &sa;
+			port = ntohs(ipv4->sin_port);
+			break;
+		case PF_INET6:
+			szFamily = "IPv6";
+			ipv6 = (struct sockaddr_in6*) &sa;
+			port = ntohs(ipv6->sin6_port);
+			break;
+		default:
+			szFamily = "other";
+			port = -1;
+			break;
+		}
+		dbgprintf("Listening on %s syslogd socket %d (%s/port %d).\n",
+			type, fd, szFamily, port);
+		return;
+	}
+
+	/* we can not obtain peer info. We are just providing
+	 * debug info, so this is no reason to break the program
+	 * or do any serious error reporting.
+	 */
+	dbgprintf("Listening on syslogd socket %d - could not obtain peer info.\n", fd);
+}
+
+
+/* Return a printable representation of a host address.
+ * Now (2007-07-16) also returns the full host name (if it could be obtained)
+ * in the second param [thanks to mildew@gmail.com for the patch].
+ * The caller must provide buffer space for pszHost and pszHostFQDN. These
+ * buffers must be of size NI_MAXHOST. This is not checked here, because
+ * there is no way to check it. We use this way of doing things because it
+ * frees us from using dynamic memory allocation where it really does not
+ * pay.
+ */
+rsRetVal cvthname(struct sockaddr_storage *f, uchar *pszHost, uchar *pszHostFQDN)
+{
+	DEFiRet;
+	register uchar *p;
+	int count;
+	
+	assert(f != NULL);
+	assert(pszHost != NULL);
+	assert(pszHostFQDN != NULL);
+
+	iRet = gethname(f, pszHostFQDN);
+
+	if(iRet == RS_RET_INVALID_SOURCE || iRet == RS_RET_ADDRESS_UNKNOWN) {
+		strcpy((char*) pszHost, (char*) pszHostFQDN); /* we use whatever was provided as replacement */
+		ABORT_FINALIZE(RS_RET_OK); /* this is handled, we are happy with it */
+	} else if(iRet != RS_RET_OK) {
+		FINALIZE; /* we return whatever error state we have - can not handle it */
+	}
+
+	/* if we reach this point, we obtained a non-numeric hostname and can now process it */
+
+	/* Convert to lower case */
+	for(p = pszHostFQDN ; *p ; p++)
+		if (isupper((int) *p))
+			*p = tolower(*p);
+	
+	/* OK, the fqdn is now known. Now it is time to extract only the hostname
+	 * part if we were instructed to do so.
+	 */
+	/* TODO: quick and dirty right now: we need to optimize that. We simply
+	 * copy over the buffer and then use the old code. In the long term, that should
+	 * be placed in its own function and probably outside of the net module (at least
+	 * if should no longer reley on syslogd.c's global config-setting variables).
+	 * Note that the old code always removes the local domain. We may want to
+	 * make this in option in the long term. (rgerhards, 2007-09-11)
+	 */
+	strcpy((char*)pszHost, (char*)pszHostFQDN);
+	if ((p = (uchar*) strchr((char*)pszHost, '.'))) { /* find start of domain name "machine.example.com" */
+		if(strcmp((char*) (p + 1), LocalDomain) == 0) {
+			*p = '\0'; /* simply terminate the string */
+		} else {
+			/* now check if we belong to any of the domain names that were specified
+			 * in the -s command line option. If so, remove and we are done.
+			 * TODO: this must go away! -- rgerhards, 2008-04-16
+			 * For proper modularization, this must be done different, e.g. via a
+			 * "to be stripped" property of *this* object itself.
+			 */
+			if (StripDomains) {
+				count=0;
+				while (StripDomains[count]) {
+					if (strcmp((char*)(p + 1), StripDomains[count]) == 0) {
+						*p = '\0';
+						FINALIZE; /* we are done */
+					}
+					count++;
+				}
+			}
+			/* if we reach this point, we have not found any domain we should strip. Now
+			 * we try and see if the host itself is listed in the -l command line option
+			 * and so should be stripped also. If so, we do it and return. Please note that
+			 * -l list FQDNs, not just the hostname part. If it did just list the hostname, the
+			 * door would be wide-open for all kinds of mixing up of hosts. Because of this,
+			 * you'll see comparison against the full string (pszHost) below. The termination
+			 * still occurs at *p, which points at the first dot after the hostname.
+			 * TODO: this must also go away - see comment above -- rgerhards, 2008-04-16
+			 */
+			if (LocalHosts) {
+				count=0;
+				while (LocalHosts[count]) {
+					if (!strcmp((char*)pszHost, LocalHosts[count])) {
+						*p = '\0';
+						break; /* we are done */
+					}
+					count++;
+				}
+			}
+		}
+	}
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* get the name of the local host. A pointer to a character pointer is passed
+ * in, which on exit points to the local hostname. This buffer is dynamically
+ * allocated and must be free()ed by the caller. If the functions returns an
+ * error, the pointer is NULL. This function is based on GNU/Hurd's localhostname
+ * function.
+ * rgerhards, 20080-04-10
+ */
+static rsRetVal
+getLocalHostname(uchar **ppName)
+{
+	DEFiRet;
+	uchar *buf = NULL;
+	size_t buf_len = 0;
+
+	assert(ppName != NULL);
+
+	do {
+		if(buf == NULL) {
+			buf_len = 128;        /* Initial guess */
+			CHKmalloc(buf = malloc(buf_len));
+		} else {
+			buf_len += buf_len;
+			CHKmalloc(buf = realloc (buf, buf_len));
+		}
+	} while((gethostname((char*)buf, buf_len) == 0 && !memchr (buf, '\0', buf_len)) || errno == ENAMETOOLONG);
+
+	*ppName = buf;
+	buf = NULL;
+
+finalize_it:
+	if(iRet != RS_RET_OK) {
+		if(buf != NULL)
+			free(buf);
+	}
+	RETiRet;
+}
+
+
+/* closes the UDP listen sockets (if they exist) and frees
+ * all dynamically assigned memory. 
+ */
+void closeUDPListenSockets(int *pSockArr)
+{
+	register int i;
+
+	assert(pSockArr != NULL);
+        if(pSockArr != NULL) {
+	        for (i = 0; i < *pSockArr; i++)
+	                close(pSockArr[i+1]);
+		free(pSockArr);
+	}
+}
+
+
+/* creates the UDP listen sockets
+ * hostname and/or pszPort may be NULL, but not both!
+ * bIsServer indicates if a server socket should be created
+ * 1 - server, 0 - client
+ */
+int *create_udp_socket(uchar *hostname, uchar *pszPort, int bIsServer)
+{
+        struct addrinfo hints, *res, *r;
+        int error, maxs, *s, *socks, on = 1;
+	int sockflags;
+
+	assert(!((pszPort == NULL) && (hostname == NULL)));
+        memset(&hints, 0, sizeof(hints));
+	if(bIsServer)
+		hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV;
+	else
+		hints.ai_flags = AI_NUMERICSERV;
+        hints.ai_family = family;
+        hints.ai_socktype = SOCK_DGRAM;
+        error = getaddrinfo((char*) hostname, (char*) pszPort, &hints, &res);
+        if(error) {
+               errmsg.LogError(NO_ERRCODE, "%s",  gai_strerror(error));
+	       errmsg.LogError(NO_ERRCODE, "UDP message reception disabled due to error logged in last message.\n");
+	       return NULL;
+	}
+
+        /* Count max number of sockets we may open */
+        for (maxs = 0, r = res; r != NULL ; r = r->ai_next, maxs++)
+		/* EMPTY */;
+        socks = malloc((maxs+1) * sizeof(int));
+        if (socks == NULL) {
+               errmsg.LogError(NO_ERRCODE, "couldn't allocate memory for UDP sockets, suspending UDP message reception");
+               freeaddrinfo(res);
+               return NULL;
+        }
+
+        *socks = 0;   /* num of sockets counter at start of array */
+        s = socks + 1;
+	for (r = res; r != NULL ; r = r->ai_next) {
+               *s = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
+        	if (*s < 0) {
+			if(!(r->ai_family == PF_INET6 && errno == EAFNOSUPPORT))
+				errmsg.LogError(NO_ERRCODE, "create_udp_socket(), socket");
+				/* it is debateble if PF_INET with EAFNOSUPPORT should
+				 * also be ignored...
+				 */
+                        continue;
+                }
+
+#		ifdef IPV6_V6ONLY
+                if (r->ai_family == AF_INET6) {
+                	int ion = 1;
+			if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY,
+			      (char *)&ion, sizeof (ion)) < 0) {
+			errmsg.LogError(NO_ERRCODE, "setsockopt");
+			close(*s);
+			*s = -1;
+			continue;
+                	}
+                }
+#		endif
+
+		/* if we have an error, we "just" suspend that socket. Eventually
+		 * other sockets will work. At the end of this function, we check
+		 * if we managed to open at least one socket. If not, we'll write
+		 * a "inet suspended" message and declare failure. Else we use
+		 * what we could obtain.
+		 * rgerhards, 2007-06-22
+		 */
+       		if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR,
+			       (char *) &on, sizeof(on)) < 0 ) {
+			errmsg.LogError(NO_ERRCODE, "setsockopt(REUSEADDR)");
+                        close(*s);
+			*s = -1;
+			continue;
+		}
+
+		/* We need to enable BSD compatibility. Otherwise an attacker
+		 * could flood our log files by sending us tons of ICMP errors.
+		 */
+#if !defined(OS_BSD) && !defined(__hpux)
+		if (should_use_so_bsdcompat()) {
+			if (setsockopt(*s, SOL_SOCKET, SO_BSDCOMPAT,
+					(char *) &on, sizeof(on)) < 0) {
+				errmsg.LogError(NO_ERRCODE, "setsockopt(BSDCOMPAT)");
+                                close(*s);
+				*s = -1;
+				continue;
+			}
+		}
+#endif
+		/* We must not block on the network socket, in case a packet
+		 * gets lost between select and recv, otherwise the process
+		 * will stall until the timeout, and other processes trying to
+		 * log will also stall.
+		 * Patch vom Colin Phipps <cph@cph.demon.co.uk> to the original
+		 * sysklogd source. Applied to rsyslogd on 2005-10-19.
+		 */
+		if ((sockflags = fcntl(*s, F_GETFL)) != -1) {
+			sockflags |= O_NONBLOCK;
+			/* SETFL could fail too, so get it caught by the subsequent
+			 * error check.
+			 */
+			sockflags = fcntl(*s, F_SETFL, sockflags);
+		}
+		if (sockflags == -1) {
+			errmsg.LogError(NO_ERRCODE, "fcntl(O_NONBLOCK)");
+                        close(*s);
+			*s = -1;
+			continue;
+		}
+
+		if(bIsServer) {
+			/* rgerhards, 2007-06-22: if we run on a kernel that does not support
+			 * the IPV6_V6ONLY socket option, we need to use a work-around. On such
+			 * systems the IPv6 socket does also accept IPv4 sockets. So an IPv4
+			 * socket can not listen on the same port as an IPv6 socket. The only
+			 * workaround is to ignore the "socket in use" error. This is what we
+			 * do if we have to.
+			 */
+			if(     (bind(*s, r->ai_addr, r->ai_addrlen) < 0)
+	#		ifndef IPV6_V6ONLY
+			     && (errno != EADDRINUSE)
+	#		endif
+			   ) {
+				errmsg.LogError(NO_ERRCODE, "bind");
+				close(*s);
+				*s = -1;
+				continue;
+			}
+		}
+
+                (*socks)++;
+                s++;
+	}
+
+        if(res != NULL)
+               freeaddrinfo(res);
+
+	if(Debug && *socks != maxs)
+		dbgprintf("We could initialize %d UDP listen sockets out of %d we received "
+		 	"- this may or may not be an error indication.\n", *socks, maxs);
+
+        if(*socks == 0) {
+		errmsg.LogError(NO_ERRCODE, "No UDP listen socket could successfully be initialized, "
+			 "message reception via UDP disabled.\n");
+		/* we do NOT need to free any sockets, because there were none... */
+        	free(socks);
+		return(NULL);
+	}
+
+	return(socks);
+}
+
+
+/* queryInterface function
+ * rgerhards, 2008-03-05
+ */
+BEGINobjQueryInterface(net)
+CODESTARTobjQueryInterface(net)
+	if(pIf->ifVersion != netCURR_IF_VERSION) { /* check for current version, increment on each change */
+		ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED);
+	}
+
+	/* ok, we have the right interface, so let's fill it
+	 * Please note that we may also do some backwards-compatibility
+	 * work here (if we can support an older interface version - that,
+	 * of course, also affects the "if" above).
+	 */
+	pIf->cvthname = cvthname;
+	/* things to go away after proper modularization */
+	pIf->addAllowedSenderLine = addAllowedSenderLine;
+	pIf->PrintAllowedSenders = PrintAllowedSenders;
+	pIf->clearAllowedSenders = clearAllowedSenders;
+	pIf->debugListenInfo = debugListenInfo;
+	pIf->create_udp_socket = create_udp_socket;
+	pIf->closeUDPListenSockets = closeUDPListenSockets;
+	pIf->isAllowedSender = isAllowedSender;
+	pIf->should_use_so_bsdcompat = should_use_so_bsdcompat;
+	pIf->getLocalHostname = getLocalHostname;
+finalize_it:
+ENDobjQueryInterface(net)
+
+
+/* exit our class
+ * rgerhards, 2008-03-10
+ */
+BEGINObjClassExit(net, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */
+CODESTARTObjClassExit(net)
+	/* release objects we no longer need */
+	objRelease(errmsg, CORE_COMPONENT);
+ENDObjClassExit(net)
+
+
+/* Initialize the net class. Must be called as the very first method
+ * before anything else is called inside this class.
+ * rgerhards, 2008-02-19
+ */
+BEGINAbstractObjClassInit(net, 1, OBJ_IS_CORE_MODULE) /* class, version */
+	/* request objects we use */
+	CHKiRet(objUse(errmsg, CORE_COMPONENT));
+
+	/* set our own handlers */
+ENDObjClassInit(net)
+
+
+/* --------------- here now comes the plumbing that makes as a library module --------------- */
+
+
+BEGINmodExit
+CODESTARTmodExit
+	netClassExit();
+ENDmodExit
+
+
+BEGINqueryEtryPt
+CODESTARTqueryEtryPt
+CODEqueryEtryPt_STD_LIB_QUERIES
+ENDqueryEtryPt
+
+
+BEGINmodInit()
+CODESTARTmodInit
+	*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
+
+	/* Initialize all classes that are in our module - this includes ourselfs */
+	CHKiRet(netClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
+ENDmodInit
+/* vi:set ai:
+ */