From 1194eac60016bd35054b94135d5309376a84d64c Mon Sep 17 00:00:00 2001
From: "Jean-Marc Pigeon (Delson)" <jmp@safe.ca>
Date: Fri, 16 Aug 2024 07:52:47 -0400
Subject: [PATCH] Working on checkmx

---
 lib/subrou.c |  2 +-
 lib/unidns.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/unidns.h | 10 ++++++
 3 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/lib/subrou.c b/lib/subrou.c
index 6286fee..2682e3a 100644
--- a/lib/subrou.c
+++ b/lib/subrou.c
@@ -21,7 +21,7 @@
 
 //version definition 
 #define VERSION "0.4.2"
-#define RELEASE "14"
+#define RELEASE "15"
 
 //Public variables
 PUBLIC  int debug=0;            //debug level
diff --git a/lib/unidns.c b/lib/unidns.c
index 394abab..3e99255 100644
--- a/lib/unidns.c
+++ b/lib/unidns.c
@@ -66,6 +66,25 @@ if (debug>-dbg) {
 */
 /********************************************************/
 /*                                                      */
+/*	Procedure to compare 2 MX and return	        */
+/*	a value according preference value	        */
+/*                                                      */
+/********************************************************/
+static int cmpmx(const void *p1,const void *p2)
+
+{
+MXTYP *m1;
+MXTYP *m2;
+
+m1=((MXTYP **)p1)[0];
+m2=((MXTYP **)p2)[0];
+return m1->preference-m2->preference;
+}
+/*
+
+*/
+/********************************************************/
+/*                                                      */
 /*	Procedure to parse mechanisme string            */
 /*                                                      */
 /********************************************************/
@@ -690,6 +709,84 @@ switch  (spf) {
   }
 return ascii;
 
+#undef  OPEP
+}
+/*
+^L
+*/
+/********************************************************/
+/*                                                      */
+/*	Procedure to extract a domain MX.       	*/
+/*	If the domain doesn't exist or domain   	*/
+/*	do not have a MX, a void pointer is	        */
+/*	returned.				        */
+/*	Retuned list is ordered according 	        */
+/*	MX preference (low preference first)	        */
+/*                                                      */
+/********************************************************/
+PUBLIC MXTYP **dns_getmx(char *domain)
+
+{
+#define OPEP    "unidns.c:dns_getmx"
+
+MXTYP **mxlist;
+char **list;
+int answer;
+RSPTYP rsp;
+int phase;
+_Bool proceed;
+
+mxlist=(MXTYP **)0;
+list=(char **)0;
+answer=0;
+(void) memset(&rsp,'\000',sizeof(rsp)); 
+phase=0;
+proceed=true;
+while (proceed==true) {
+  switch (phase) {
+    case 0      :       //Are the parameters available
+      if ((domain==(char *)0)||(strlen(domain)==0)) {
+        (void) rou_alert(0,"%s missing domainame",OPEP);
+        phase=999;      //trouble trouble
+        }
+      break;
+    case 1      :       //Requesting MX for domain
+      answer=myquery(domain,C_IN,T_MX,rsp.buf,sizeof(rsp.buf));
+      if (answer<=0) 
+        phase=999;      //Trouble trouble to get MX
+      break;
+    case 2      :       //extracting result
+      if (answer>=sizeof(rsp.buf))
+        answer=sizeof(rsp.buf)-1;
+      list=extracting(&rsp,answer,domain,"MX");
+      if (list==(char **)0)
+        phase=999;      //list empty?
+      break;
+    case 3      :       //ordering list
+      answer=0;
+      for (int i=0;list[i]!=(char *)0;i+=2) {
+	if ((list[i+1]!=(char *)0)&&(strlen(list[i+1])>0)) {
+	  MXTYP *mx;
+
+	  mx=(MXTYP *)calloc(1,sizeof(MXTYP));
+	  mx->preference=atoi(list[i]);
+	  mx->mxname=strdup(list[i+1]);
+	  mxlist=(MXTYP **)rou_addlist((void **)mxlist,(void *)mx);
+          answer++;
+	  }
+        }
+      if (answer>0)
+        (void) qsort((void *)mxlist,answer,sizeof(MXTYP *),cmpmx);
+      list=(char **)rou_freelist((void **)list,(freehandler_t)rou_freestr);
+      break;
+    default     :       //SAFE guard
+      proceed=false;
+      break;
+    }
+  phase++;
+  }
+return mxlist;
+
 #undef  OPEP
 }
 /*
diff --git a/lib/unidns.h b/lib/unidns.h
index 4c8342a..c83fcdc 100644
--- a/lib/unidns.h
+++ b/lib/unidns.h
@@ -21,9 +21,19 @@ typedef	enum	{
 	spf_unknown	//Unknown SPF directive
 	}SPFENU;
 
+//defining an MX structure
+typedef	struct	{
+	int preference;	/*MX preference		*/
+	char *mxname;	/*MX hostname		*/
+	}MXTYP;
+
 //procedure to return spf status as an ASCII string
 extern const char *dns_spfASCII(SPFENU spf);
 
+//procedure to get a list of MX IP releated to a specific
+//domain.
+extern MXTYP **dns_getmx(char *domain);
+
 //get the SPF status for a specific domain and a remote peer IP
 extern SPFENU dns_get_spf_status(int *try,char *domain,AFNTYP *afnnum);
 
-- 
2.47.3