X-Git-Url: https://code.citadel.org/?a=blobdiff_plain;f=citadel%2Fdomain.c;h=3c4f1455c375d03693a93b349db36b4bb32c9ec3;hb=ea55c1f82ea74c3837ad694c238f40744044aed7;hp=0f61f4a4488ae5e4ead29d8e25148a3e84bc9049;hpb=a0e8c30d9f915c864be900f2a539940070a5e920;p=citadel.git

diff --git a/citadel/domain.c b/citadel/domain.c
index 0f61f4a44..3c4f1455c 100644
--- a/citadel/domain.c
+++ b/citadel/domain.c
@@ -1,43 +1,91 @@
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <netinet/in.h>
+/*
+ * DNS lookup for SMTP sender
+ *
+ * Copyright (c) 1987-2021 by the citadel.org team
+ *
+ * This program is open source software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 3.
+ *
+ * This program 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 General Public License for more details.
+ */
+
+#include "sysdep.h"
+#include <stdio.h>
+#include <syslog.h>
+#ifdef HAVE_RESOLV_H
 #include <arpa/nameser.h>
+#ifdef HAVE_ARPA_NAMESER_COMPAT_H
+#include <arpa/nameser_compat.h>
+#endif
 #include <resolv.h>
+#endif
+#include <libcitadel.h>
 #include "sysdep_decls.h"
 #include "citadel.h"
 #include "domain.h"
-#include "server.h"
+#include "internet_addressing.h"
 
-#define SMART_HOST	"gatekeeper.wdcs.com"
 
 /*
- * sort_mxrecs()
- *
- * Sort a pile of MX records (struct mx, definted in domain.h) by preference
- *
+ * get_hosts() checks the Internet configuration for various types of
+ * entries and returns them in the same format as getmx() does -- fill the
+ * buffer with a delimited list of hosts and return the number of hosts.
+ * 
+ * This is used to fetch MX smarthosts, SpamAssassin hosts, etc.
  */
-void sort_mxrecs(struct mx *mxrecs, int num_mxrecs) {
-	int a, b;
-	struct mx hold1, hold2;
-
-	if (num_mxrecs < 2) return;
+int get_hosts(char *mxbuf, char *rectype) {
+	int config_lines;
+	int i;
+	char buf[256];
+	char host[256], type[256];
+	int total_smarthosts = 0;
+
+	if (inetcfg == NULL) return(0);
+	strcpy(mxbuf, "");
 
-	/* do the sort */
-	for (a = num_mxrecs - 2; a >= 0; --a) {
-		for (b = 0; b <= a; ++b) {
-			if (mxrecs[b].pref > mxrecs[b+1].pref) {
+	config_lines = num_tokens(inetcfg, '\n');
+	for (i=0; i<config_lines; ++i) {
+		extract_token(buf, inetcfg, i, '\n', sizeof buf);
+		extract_token(host, buf, 0, '|', sizeof host);
+		extract_token(type, buf, 1, '|', sizeof type);
 
-				memcpy(&hold1, &mxrecs[b], sizeof(struct mx));
-				memcpy(&hold2, &mxrecs[b+1], sizeof(struct mx));
-				memcpy(&mxrecs[b], &hold2, sizeof(struct mx));
-				memcpy(&mxrecs[b+1], &hold1, sizeof(struct mx));
-			}
+		if (!strcasecmp(type, rectype)) {
+			strcat(mxbuf, host);
+			strcat(mxbuf, "|");
+			++total_smarthosts;
 		}
 	}
+
+	return(total_smarthosts);
 }
 
 
+/*
+ * Compare the preference of two MX records.  First check by the actual
+ * number listed in the MX record.  If they're identical, randomize the
+ * result.
+ */
+int mx_compare_pref(const void *mx1, const void *mx2) {
+	int pref1;
+	int pref2;
+
+	pref1 = ((const struct mx *)mx1)->pref;
+	pref2 = ((const struct mx *)mx2)->pref;
+
+	if (pref1 > pref2) {
+		return(1);
+	}
+	else if (pref1 < pref2) {
+		return(0);
+	}
+	else {
+		return(rand() % 2);
+	}
+}
+
 
 /* 
  * getmx()
@@ -50,13 +98,19 @@ void sort_mxrecs(struct mx *mxrecs, int num_mxrecs) {
  *
  */
 int getmx(char *mxbuf, char *dest) {
-	char answer[1024];
+
+#ifdef HAVE_RESOLV_H
+	union {
+			u_char bytes[1024];
+			HEADER header;
+    } answer;
+#endif
+
 	int ret;
 	unsigned char *startptr, *endptr, *ptr;
 	char expanded_buf[1024];
 	unsigned short pref, type;
-	int n;
-	HEADER *hp;
+	int n = 0;
 	int qdcount;
 
 	struct mx *mxrecs = NULL;
@@ -65,88 +119,93 @@ int getmx(char *mxbuf, char *dest) {
 	/* If we're configured to send all mail to a smart-host, then our
 	 * job here is really easy.
 	 */
-	if (0) {	/* FIX */
-		strcpy(mxbuf, SMART_HOST);
-		return(1);
+	n = get_hosts(mxbuf, "smarthost");
+	if (n > 0) {
+		return(n);
 	}
 
-	/* No smart-host?  Look up the best MX for a site.
+	/*
+	 * No smart-host?  Look up the best MX for a site.
+	 * Make a call to the resolver library.
 	 */
-	ret = res_query(
-		dest,
-		C_IN, T_MX, (unsigned char *)answer, sizeof(answer)  );
+
+	ret = res_query(dest, C_IN, T_MX, (unsigned char *)answer.bytes, sizeof(answer));
 
 	if (ret < 0) {
-		lprintf(5, "No MX found\n");
-		return(0);
+		mxrecs = malloc(sizeof(struct mx));
+		mxrecs[0].pref = 0;
+		strcpy(mxrecs[0].host, dest);
+		num_mxrecs = 1;
 	}
-
-	/* If we had to truncate, shrink the number to avoid fireworks */
-	if (ret > sizeof(answer))
-		ret = sizeof(answer);
-
-	hp = (HEADER *)&answer[0];
-	startptr = &answer[0];		/* start and end of buffer */
-	endptr = &answer[ret];
-	ptr = startptr + HFIXEDSZ;	/* advance past header */
-
-	for (qdcount = ntohs(hp->qdcount); qdcount--; ptr += ret + QFIXEDSZ) {
-		if ((ret = dn_skipname(ptr, endptr)) < 0) {
-			lprintf(9, "dn_skipname error\n");
-			return(0);
+	else {
+		/* If we had to truncate, shrink the number to avoid fireworks */
+		if (ret > sizeof(answer)) {
+			ret = sizeof(answer);
 		}
-	}
-
-	while(1) {
-		memset(expanded_buf, 0, sizeof(expanded_buf));
-		ret = dn_expand(startptr,
-				endptr,
-				ptr,
-				expanded_buf,
-				sizeof(expanded_buf)
-				);
-		if (ret < 0) break;
-		ptr += ret;
-
-		GETSHORT(type, ptr);
-		ptr += INT16SZ + INT32SZ;
-		GETSHORT(n, ptr);
-
-		if (type != T_MX) {
-			ptr += n;
+	
+		startptr = &answer.bytes[0];		// start and end of buffer
+		endptr = &answer.bytes[ret];
+		ptr = startptr + HFIXEDSZ;		// advance past header
+	
+		for (qdcount = ntohs(answer.header.qdcount); qdcount--; ptr += ret + QFIXEDSZ) {
+			if ((ret = dn_skipname(ptr, endptr)) < 0) {
+				syslog(LOG_DEBUG, "domain: dn_skipname error");
+				return(0);
+			}
 		}
-
-		else {
-			GETSHORT(pref, ptr);
-			ret = dn_expand(startptr,
-					endptr,
-					ptr,
-					expanded_buf,
-					sizeof(expanded_buf)
-					);
+	
+		while(1) {
+			memset(expanded_buf, 0, sizeof(expanded_buf));
+			ret = dn_expand(startptr, endptr, ptr, expanded_buf, sizeof(expanded_buf));
+			if (ret < 0) break;
 			ptr += ret;
-
-			++num_mxrecs;
-			if (mxrecs == NULL) {
-				mxrecs = mallok(sizeof(struct mx));
+	
+			GETSHORT(type, ptr);
+			ptr += INT16SZ + INT32SZ;
+			GETSHORT(n, ptr);
+	
+			if (type != T_MX) {
+				ptr += n;
 			}
+	
 			else {
-				mxrecs = reallok(mxrecs,
-					(sizeof(struct mx) * num_mxrecs) );
+				GETSHORT(pref, ptr);
+				ret = dn_expand(startptr, endptr, ptr, expanded_buf, sizeof(expanded_buf));
+				ptr += ret;
+	
+				// If there are no MX records for the domain, resolv will give us a single one with zero length.
+				// Make sure we only record actual MX records and not the blank.
+				if (strlen(expanded_buf) > 0) {
+					++num_mxrecs;
+					if (mxrecs == NULL) {
+						mxrecs = malloc(sizeof(struct mx));
+					}
+					else {
+						mxrecs = realloc(mxrecs, (sizeof(struct mx) * num_mxrecs) );
+					}
+	
+					mxrecs[num_mxrecs - 1].pref = pref;
+					strcpy(mxrecs[num_mxrecs - 1].host, expanded_buf);
+				}
 			}
-
-			mxrecs[num_mxrecs - 1].pref = pref;
-			strcpy(mxrecs[num_mxrecs - 1].host, expanded_buf);
 		}
 	}
 
-	sort_mxrecs(mxrecs, num_mxrecs);
+	/* Sort the MX records by preference */
+	if (num_mxrecs > 1) {
+		qsort(mxrecs, num_mxrecs, sizeof(struct mx), mx_compare_pref);
+	}
 
 	strcpy(mxbuf, "");
 	for (n=0; n<num_mxrecs; ++n) {
 		strcat(mxbuf, mxrecs[n].host);
 		strcat(mxbuf, "|");
 	}
-	phree(mxrecs);
+	free(mxrecs);
+
+	/*
+	 * Append any fallback smart hosts we have configured.
+	 */
+	num_mxrecs += get_hosts(&mxbuf[strlen(mxbuf)], "fallbackhost");
 	return(num_mxrecs);
 }