Merge pull request #2 from 0x1eef/iscidraddr

Add support for CIDR notation (iscidraddr).

.gitignore

@@ -1 +1,2 @@
-test/runner
+test/isinetaddr
+test/iscidraddr

Makefile

@@ -7,7 +7,11 @@ CC = cc
 CFLAGS = -fstack-protector-all -I$(INCDIR) -Wall -Wextra -pedantic
 
 test:
-	$(CC) $(CFLAGS) $(SRCDIR)/isinetaddr.c $(TESTDIR)/isinetaddr_test.c -o $(TESTBIN)
-	$(TESTBIN)
+	@$(CC) $(CFLAGS) $(SRCDIR)/isinetaddr.c $(TESTDIR)/isinetaddr_test.c -o $(TESTDIR)/isinetaddr
+	@echo -n test/isinetaddr: ''
+	@$(TESTDIR)/isinetaddr
+	@$(CC) $(CFLAGS) $(SRCDIR)/isinetaddr.c $(TESTDIR)/iscidraddr_test.c -o $(TESTDIR)/iscidraddr
+	@echo -n test/iscidraddr: ''
+	@$(TESTDIR)/isinetaddr
 
 .PHONY: test

README.md

@@ -1,8 +1,9 @@
 ## About
 
 isinetaddr is a simple C library that provides an interface that can
-be used to validate one or more IPv4 addresses. The library is guided
-by easy to extend [testcases](test/) that help verify safety and correctness.
+be used to validate one or more IPv4 addresses (with optional support
+for CIDR notation as well). The library is guided by easy to extend
+[testcases](test/) that help verify safety and correctness.
 
 ## Examples
 
@@ -58,6 +59,69 @@ foobar is an invalid IPv4 address
 0.0.0.0.0 is an invalid IPv4 address
 ```
 
+### CIDR notation (IPv4)
+
+The `iscidraddr` function supports the same feature set as `isinetaddr`, and
+in addition supports
+[CIDR notation](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#CIDR_notation).
+The following example builds on the previous example:
+
+```C
+#include <isinetaddr.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+const char *strings[] = {
+  /* valid */
+  "127.0.0.1",
+  "1.1.1.1",
+  "0.0.0.0",
+  "127.0.0.1/8",
+  "127.0.0.1/16",
+  "127.0.0.1/32",
+
+  /* invalid */
+  "foobar",
+  "0.0.0.0.0",
+  "127.0.0.1/33",
+  "127.0.0.1/64"
+};
+
+int
+main(void)
+{
+    const char *str;
+    const int i = sizeof(strings) / sizeof(strings[0]);
+    for (int j = 0; j < i; j++) {
+        str = strings[j];
+        if (iscidraddr(str)) {
+            printf("%s is a valid IPv4 address\n", str);
+        } else {
+            printf("%s is an invalid IPv4 address\n", str);
+        }
+    }
+    return EXIT_SUCCESS;
+}
+```
+
+When the above source code is compiled and run the output is
+expected to be as follows:
+
+```
+$ cc -Iinclude src/isinetaddr.c share/isinetaddr/examples/iscidraddr.c -o example
+$ ./example
+127.0.0.1 is a valid IPv4 address
+1.1.1.1 is a valid IPv4 address
+0.0.0.0 is a valid IPv4 address
+127.0.0.1/8 is a valid IPv4 address
+127.0.0.1/16 is a valid IPv4 address
+127.0.0.1/32 is a valid IPv4 address
+foobar is an invalid IPv4 address
+0.0.0.0.0 is an invalid IPv4 address
+127.0.0.1/33 is an invalid IPv4 address
+127.0.0.1/64 is an invalid IPv4 address
+```
+
 ## Sources
 
 * [Source code (GitHub)](https://github.com/0x1eef/isinetaddr#readme)

include/isinetaddr.h

@@ -1,2 +1,3 @@
 #pragma once
 int isinetaddr(const char *str);
+int iscidraddr(const char *str);

share/isinetaddr/examples/iscidraddr.c

@@ -0,0 +1,34 @@
+#include <isinetaddr.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+const char *strings[] = {
+  /* valid */
+  "127.0.0.1",
+  "1.1.1.1",
+  "0.0.0.0",
+  "127.0.0.1/8",
+  "127.0.0.1/16",
+  "127.0.0.1/32",
+
+  /* invalid */
+  "foobar",
+  "0.0.0.0.0",
+  "127.0.0.1/33",
+};
+
+int
+main(void)
+{
+    const char *str;
+    const int i = sizeof(strings) / sizeof(strings[0]);
+    for (int j = 0; j < i; j++) {
+        str = strings[j];
+        if (iscidraddr(str)) {
+            printf("%s is a valid IPv4 address\n", str);
+        } else {
+            printf("%s is an invalid IPv4 address\n", str);
+        }
+    }
+    return EXIT_SUCCESS;
+}

src/isinetaddr.c

@@ -4,7 +4,7 @@
 #include <isinetaddr.h>
 #include <errno.h>
 
-static int in_range(char buf[4], int buflen);
+static int in_range(char buf[4], int min, int max);
 static void register_octet(int *octets, char *buf, int *buflen);
 static void register_digit(char digit, int *digits, char *buf, int *buflen);
 
@@ -19,7 +19,7 @@ isinetaddr(const char *str)
     if (str[l] == '.') {
       if (buflen == 0) {
         return 0;
-      } else if (!in_range(buf, buflen)) {
+      } else if (!in_range(buf, 0, 255)) {
         return 0;
       } else {
         register_octet(&octets, buf, &buflen);
@@ -35,24 +35,43 @@ isinetaddr(const char *str)
     }
   }
   if (octets == 4) {
-    return digits <= 12 && in_range(buf, buflen) && buflen > 0;
+    return buflen > 0 && digits <= 12 && in_range(buf, 0, 255);
   } else {
     return 0;
   }
 }
 
+int
+iscidraddr(const char *str)
+{
+  size_t offset = 0;
+  size_t len = (str == NULL ? 0 : strnlen(str, 20));
+
+  for(size_t i = 0; i < len; i++) {
+    if(str[i] == '/') {
+      offset = i;
+    }
+  }
+  if (offset == 0) {
+    return isinetaddr(str);
+  } else {
+    char addr[offset], cidr[3];
+    char *c = (char*)&str[offset + 1];
+    memcpy(addr, str, offset);
+    memcpy(cidr, c, 2);
+    addr[offset] = '\0';
+    return isinetaddr(addr) && in_range(cidr, 0, 32);
+  }
+}
+
 static int
-in_range(char buf[4], int buflen)
+in_range(char buf[4], int min, int max)
 {
   char *err;
   long r;
-  if (buflen < 3) {
-    return 1;
-  } else {
-    errno = 0;
-    r = strtol(buf, &err, 10);
-    return *err == '\0' && errno == 0 && (r >= 0 && r <= 255);
-  }
+  errno = 0;
+  r = strtol(buf, &err, 10);
+  return *err == '\0' && errno == 0 && (r >= min && r <= max);
 }
 
 static void

test/iscidraddr_test.c

@@ -0,0 +1,62 @@
+#include <isinetaddr.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+const char *valid[] = {
+  "192.168.1.1",
+  "0.0.0.0",
+  "255.255.255.255",
+  "123.45.67.89",
+  "123.45.67.255",
+  "10.0.0.1/32"
+};
+
+const char *invalid[] = {
+  "123.45.67.891",
+  "192.168.500.1",
+  ".192.168.1.1",
+  "192..168.1.1",
+  "192.168.1.1.",
+  "192.168.1.1..",
+  "192.168.1.1a",
+  "555555555555555555555555555555555555",
+  "",
+  ".",
+  ".......",
+  "192.2.2.",
+  "...4",
+  "4...4",
+  "10.0.0.1/33",
+  "127.0.0.1/64",
+  "127.0.0.1/",
+  "127.0.0.1/a",
+  "/",
+  "/123.",
+  "127/2",
+  NULL
+};
+
+int
+main(void) {
+  size_t len;
+  /* IPv4: valid */
+  len = sizeof(valid) / sizeof(valid[0]);
+  for (size_t i = 0; i < len; i++) {
+    if (iscidraddr(valid[i]) != 1) {
+      fprintf(stderr, "assertion failed: '%s' should be valid\n", valid[i]);
+      abort();
+    }
+  }
+  /* IPv4: invalid */
+  len = sizeof(invalid) / sizeof(invalid[0]);
+  for (size_t i = 0; i < len; i++) {
+    if (iscidraddr(invalid[i]) != 0) {
+      fprintf(stderr, "assertion failed: '%s' should NOT be valid\n", invalid[i]);
+      abort();
+    }
+  }
+  /* Done */
+  printf("OK\n");
+  return EXIT_SUCCESS;
+}

test/isinetaddr_test.c

@@ -8,7 +8,7 @@ const char *valid[] = {
   "0.0.0.0",
   "255.255.255.255",
   "123.45.67.89",
-  "123.45.67.255",
+  "123.45.67.255"
 };
 
 const char *invalid[] = {