Add some files

portscanner.c

@@ -0,0 +1,89 @@
+/*
+    Port scanner code in c
+*/
+#include "stdio.h"
+#include "sys/socket.h"
+#include "errno.h"
+#include "netdb.h"
+#include "string.h"
+#include "stdlib.h"
+ 
+int main(int argc , char **argv)
+{
+    struct hostent *host;
+    int err, i , sock ,start , end;
+    char hostname[100];
+    struct sockaddr_in sa;
+     
+    //Get the hostname to scan
+    printf("Enter hostname or IP : ");
+    gets(hostname);
+     
+    //Get start port number
+    printf("\nEnter start port number : ");
+    scanf("%d" , &start);
+     
+    //Get end port number
+    printf("Enter end port number : ");
+    scanf("%d" , &end);
+ 
+    //Initialise the sockaddr_in structure
+    strncpy((char*)&sa , "" , sizeof sa);
+    sa.sin_family = AF_INET;
+     
+    //direct ip address, use it
+    if(isdigit(hostname[0]))
+    {
+        printf("Doing inet_addr...");
+        sa.sin_addr.s_addr = inet_addr(hostname);
+        printf("Done\n");
+    }
+    //Resolve hostname to ip address
+    else if( (host = gethostbyname(hostname)) != 0)
+    {
+        printf("Doing gethostbyname...");
+        strncpy((char*)&sa.sin_addr , (char*)host->h_addr , sizeof sa.sin_addr);
+        printf("Done\n");
+    }
+    else
+    {
+        herror(hostname);
+        exit(2);
+    }
+     
+    //Start the port scan loop
+    printf("Starting the portscan loop : \n");
+    for( i = start ; i <= end ; i++) 
+    {
+        //Fill in the port number
+        sa.sin_port = htons(i);
+        //Create a socket of type internet
+        sock = socket(AF_INET , SOCK_STREAM , 0);
+         
+        //Check whether socket created fine or not
+        if(sock < 0) 
+        {
+            perror("\nSocket");
+            exit(1);
+        }
+        //Connect using that socket and sockaddr structure
+        err = connect(sock , (struct sockaddr*)&sa , sizeof sa);
+         
+        //not connected
+        if( err < 0 )
+        {
+            //printf("%s %-5d %s\r" , hostname , i, strerror(errno));
+            fflush(stdout);
+        }
+        //connected
+        else
+        {
+            printf("%-5d open\n",  i);
+        }
+        close(sock);
+    }
+     
+    printf("\r");
+    fflush(stdout);
+    return(0);
+} 

test.c

@@ -0,0 +1,11 @@
+#include "stdio.h"
+
+void main(){
+	
+	int a;
+	printf("Enter a: ");
+	scanf("%d",a);
+	printf(a);
+
+	
+}