X-Git-Url: https://code.citadel.org/?a=blobdiff_plain;f=citadel%2Fdomain.c;h=3c4f1455c375d03693a93b349db36b4bb32c9ec3;hb=ea55c1f82ea74c3837ad694c238f40744044aed7;hp=d7bd402de868f2352e71b8ba91331c43c868da91;hpb=119f5ee3d14919e18afc159074295c51e5f911ba;p=citadel.git

diff --git a/citadel/domain.c b/citadel/domain.c
index d7bd402de..3c4f1455c 100644
--- a/citadel/domain.c
+++ b/citadel/domain.c
@@ -1,17 +1,20 @@
 /*
- * $Id$
- *
  * 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 <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <netinet/in.h>
 #include <stdio.h>
-
+#include <syslog.h>
 #ifdef HAVE_RESOLV_H
 #include <arpa/nameser.h>
 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
@@ -19,12 +22,10 @@
 #endif
 #include <resolv.h>
 #endif
-
+#include <libcitadel.h>
 #include "sysdep_decls.h"
 #include "citadel.h"
 #include "domain.h"
-#include "server.h"
-#include "tools.h"
 #include "internet_addressing.h"
 
 
@@ -103,9 +104,6 @@ int getmx(char *mxbuf, char *dest) {
 			u_char bytes[1024];
 			HEADER header;
     } answer;
-#else
-	char buf[SIZ];
-	FILE *fp;
 #endif
 
 	int ret;
@@ -117,38 +115,21 @@ int getmx(char *mxbuf, char *dest) {
 
 	struct mx *mxrecs = NULL;
 	int num_mxrecs = 0;
-	
+
 	/* If we're configured to send all mail to a smart-host, then our
 	 * job here is really easy.
 	 */
 	n = get_hosts(mxbuf, "smarthost");
-	if (n > 0) return(n);
+	if (n > 0) {
+		return(n);
+	}
 
 	/*
 	 * No smart-host?  Look up the best MX for a site.
+	 * Make a call to the resolver library.
 	 */
 
-#ifndef HAVE_RESOLV_H
-
-	/*
-	 * On systems with b0rken or non-standard resolver libraries, learn
-	 * the MX records by calling "nslookup" from the command line.
-	 *
-	 * Someday.
-	 *
-	 */
-
-	return(0);
-
-#else /* HAVE_RESOLV_H */
-
-	/*
-	 * Make a call to the standard resolver library.
-	 */
-
-	ret = res_query(
-		dest,
-		C_IN, T_MX, (unsigned char *)answer.bytes, sizeof(answer)  );
+	ret = res_query(dest, C_IN, T_MX, (unsigned char *)answer.bytes, sizeof(answer));
 
 	if (ret < 0) {
 		mxrecs = malloc(sizeof(struct mx));
@@ -157,30 +138,25 @@ int getmx(char *mxbuf, char *dest) {
 		num_mxrecs = 1;
 	}
 	else {
-
 		/* If we had to truncate, shrink the number to avoid fireworks */
-		if (ret > sizeof(answer))
+		if (ret > sizeof(answer)) {
 			ret = sizeof(answer);
+		}
 	
-		startptr = &answer.bytes[0];		/* start and end of buffer */
+		startptr = &answer.bytes[0];		// start and end of buffer
 		endptr = &answer.bytes[ret];
-		ptr = startptr + HFIXEDSZ;	/* advance past header */
+		ptr = startptr + HFIXEDSZ;		// advance past header
 	
 		for (qdcount = ntohs(answer.header.qdcount); qdcount--; ptr += ret + QFIXEDSZ) {
 			if ((ret = dn_skipname(ptr, endptr)) < 0) {
-				lprintf(CTDL_DEBUG, "dn_skipname error\n");
+				syslog(LOG_DEBUG, "domain: dn_skipname error");
 				return(0);
 			}
 		}
 	
 		while(1) {
 			memset(expanded_buf, 0, sizeof(expanded_buf));
-			ret = dn_expand(startptr,
-					endptr,
-					ptr,
-					expanded_buf,
-					sizeof(expanded_buf)
-					);
+			ret = dn_expand(startptr, endptr, ptr, expanded_buf, sizeof(expanded_buf));
 			if (ret < 0) break;
 			ptr += ret;
 	
@@ -194,30 +170,26 @@ int getmx(char *mxbuf, char *dest) {
 	
 			else {
 				GETSHORT(pref, ptr);
-				ret = dn_expand(startptr,
-						endptr,
-						ptr,
-						expanded_buf,
-						sizeof(expanded_buf)
-						);
+				ret = dn_expand(startptr, endptr, ptr, expanded_buf, sizeof(expanded_buf));
 				ptr += ret;
 	
-				++num_mxrecs;
-				if (mxrecs == NULL) {
-					mxrecs = malloc(sizeof(struct mx));
-				}
-				else {
-					mxrecs = realloc(mxrecs,
-					    (sizeof(struct mx) * num_mxrecs) );
-				}
+				// 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);
+				}
 			}
 		}
 	}
-#endif /* HAVE_RESOLV_H */
 
 	/* Sort the MX records by preference */
 	if (num_mxrecs > 1) {
@@ -230,5 +202,10 @@ int getmx(char *mxbuf, char *dest) {
 		strcat(mxbuf, "|");
 	}
 	free(mxrecs);
+
+	/*
+	 * Append any fallback smart hosts we have configured.
+	 */
+	num_mxrecs += get_hosts(&mxbuf[strlen(mxbuf)], "fallbackhost");
 	return(num_mxrecs);
 }