1 files changed, 73 insertions, 0 deletions
diff --git a/checkalias.c b/checkalias.c
new file mode 100644
index 00000000..413b4047
--- /dev/null
+++ b/checkalias.c
@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include "fetchmail.h"
+
+ 
+int is_ip_alias(const char *name1,const char *name2)
+/* Given two hostnames as arguments, returns TRUE if they
+ * have at least one IP address in common.
+ * It is meant to be called by the is_host_alias() function in driver.c
+ * No check is done on errors returned by gethostbyname,
+ * the calling function does them.
+ */
+     {
+
+	typedef unsigned char address_t[sizeof (struct in_addr)]; 
+	typedef struct _address_e { struct _address_e *next;
+			address_t address;
+			} address_e;
+
+	address_e *host_a_addr, *host_b_addr,*dummy_addr;
+	
+	int i;
+
+        struct hostent *hp;
+
+        char **p;
+ 
+         hp = gethostbyname(name1);
+ 
+	 dummy_addr = (address_e *)NULL;
+
+         for (i=0,p = hp->h_addr_list; *p != 0; i++,p++) {
+	        struct in_addr in;
+		(void) memcpy(&in.s_addr, *p, sizeof (in.s_addr));
+		host_a_addr = (address_e *)xmalloc(sizeof( address_e));
+		memset (host_a_addr,0, sizeof (address_e));
+		host_a_addr->next = dummy_addr;
+		(void) memcpy(&host_a_addr->address, *p, sizeof (in.s_addr));
+		dummy_addr = host_a_addr;
+         }
+
+
+         hp = gethostbyname(name2);
+
+	 dummy_addr = (address_e *)NULL;
+
+         for (i=0,p = hp->h_addr_list; *p != 0; i++,p++) {
+		struct in_addr in;
+		(void) memcpy(&in.s_addr, *p, sizeof (in.s_addr));
+		host_b_addr = (address_e *)xmalloc(sizeof( address_e));
+		memset (host_b_addr,0, sizeof (address_e));
+		host_b_addr->next = dummy_addr;
+		(void) memcpy(&host_b_addr->address, *p, sizeof (in.s_addr));
+		dummy_addr = host_b_addr;
+         }
+
+	while (host_a_addr) {
+				while (host_b_addr) {
+
+                                if (!memcmp(host_b_addr->address,host_a_addr->address, sizeof (address_t))) return (TRUE);
+
+				host_b_addr = host_b_addr->next;
+				}
+				host_a_addr = host_a_addr->next;
+	}
+return (FALSE);
+}
+