DNS_Validator_API

Contains functions for validating and comparing DNS names

Whats here:

• include-> DNS_Validator.h (This is the header file used for function definitions)
• src-> DNS_Validator.c (Contains source code for API functions) DNS_Validator_Tests.c (Testing for functions. See here for example uses) Makefile (Used for comiling files) obj-> (Contains the object files)

Setup:

To start clone this repo.

git clone https://github.com/SeanFitz1997/DNS_Validator_API.git

Then go to src and compile the files

cd src
make

To run the tests

./DNS_Tests

Expected output:

***     Testing checkDNSValid   ***
SUCCESS: www.tcd.ie is a valid DNS and passed.
SUCCESS: www.tcd.ie. is a valid DNS and passed.
SUCCESS: . is a valid DNS and passed.
SUCCESS: www.tcd.xn--5 is a valid DNS and passed.
SUCCESS: www.tcd.xn--- is a valid DNS and passed.
SUCCESS: www.xn--_ is a valid DNS and passed.
SUCCESS: . is a valid DNS and passed.
SUCCESS: www.tcd.xn--5. is a valid DNS and passed.
SUCCESS: www.tcd.ie is a invalid DNS and failed.
SUCCESS: www.tcd.ie. is a invalid DNS and failed.
SUCCESS: . is a invalid DNS and failed.
SUCCESS: www.tcd.xn--5 is a invalid DNS and failed.
SUCCESS: www.tcd.xn--- is a invalid DNS and failed.
SUCCESS: www.xn--_ is a invalid DNS and failed.
SUCCESS: . is a invalid DNS and failed.
SUCCESS: www.tcd.xn--5. is a invalid DNS and failed.
SUCCESS: NULL DNS is invalid failed.
***     Testing compareDNSNames ***
SUCCESS: www.tcd.ie and www.tcd.ie are the same DNS and passed.
SUCCESS: www.tcd.ie and www.tcd.ie. are the same DNS and passed.
SUCCESS: www.tcd.ie and www.tcd.ief. are different DNS and failed.
SUCCESS: www.tcd.ie and www.tcf.ie are different DNS and failed.

API Functions:

int checkDNSValid(char *str);

Determines if a given DNS name is valid. Takes a null-terminated string and returns 1: If valid/true, 0: If invalid/false A DNS name is valid if it meets the following:

• Consists of a sequence of labels separated by the dot ".".
• Labels must be between 1 and 63 charcaters long.
• The overall name including dot characters must be less than 255 characters.
• May have a trailing dot (e.g. "www.tcd.ie." is valid).
• A name consisting of only a dot "." is valid (This is the root of the DNS nameing tree). No other names beging with a dot are valid.
• Valid label characters are digits(0-9), letters(A-Z) upper or lower, or a dash "-" or underscore "_" character.
• The last lable in the name (ignoring the trailing dot) may not contain a dash (“-”), underscore (“_”) or any digits, unless it starts with the string "xn--" (for internationalised top-level domain names).

int compareDNSNames(char *str1, char *str2);

Determines if two given DNS names are the same. Takes DNS names as null-terminated string and returns 1: If same/true, 0: If different/false

• If either DNS name is an invalid DNS name, it will return false.
• If either DNS name has a trailing dot, it will be ignored. eg: “www.tcd.ie” and “WwW.TcD.IE.” are the same.