sys/net/ipv4: add ipv4_addr_from_buf function

This allows to parse IPv4 address from strings that not end with '\0'.

sys/include/net/ipv4/addr.h

@@ -22,6 +22,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <stddef.h>
 
 #include "byteorder.h"
 
@@ -74,8 +75,8 @@ char *ipv4_addr_to_str(char *result, const ipv4_addr_t *addr, uint8_t result_len
  * @brief   Converts an IPv4 address string representation to a byte-represented
  *          IPv4 address
  *
- * @param[in] result    The resulting byte representation
+ * @param[out] result    The resulting byte representation
- * @param[in] addr      An IPv4 address string representation
+ * @param[in] addr       An IPv4 address string representation
  *
  * @return  @p result, on success
  * @return  NULL, if @p addr was malformed
@@ -83,6 +84,23 @@ char *ipv4_addr_to_str(char *result, const ipv4_addr_t *addr, uint8_t result_len
  */
 ipv4_addr_t *ipv4_addr_from_str(ipv4_addr_t *result, const char *addr);
 
+/**
+ * @brief   Converts an IPv4 address from a buffer of characters to a
+ *          byte-represented IPv4 address
+ *
+ * @note    @p addr_len should be between 0 and IPV4_ADDR_MAX_STR_LEN
+ *
+ * @param[out] result    The resulting byte representation
+ * @param[in] addr       An IPv4 address string representation
+ * @param[in] addr_len   The amount of characters to parse
+ *
+ * @return  @p result, on success
+ * @return  NULL, if @p addr was malformed
+ * @return  NULL, if @p result or @p addr was NULL
+ */
+ipv4_addr_t *ipv4_addr_from_buf(ipv4_addr_t *result, const char *addr,
+                                size_t addr_len);
+
 #ifdef __cplusplus
 }
 #endif

sys/net/network_layer/ipv4/addr/ipv4_addr_from_str.c

@@ -13,6 +13,7 @@
  */
 
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 
 #include "net/ipv4/addr.h"
@@ -20,12 +21,15 @@
 #define DEC     "0123456789"
 
 /* based on inet_pton4() by Paul Vixie */
-ipv4_addr_t *ipv4_addr_from_str(ipv4_addr_t *result, const char *addr)
+ipv4_addr_t *ipv4_addr_from_buf(ipv4_addr_t *result, const char *addr,
+                                size_t addr_len)
 {
-    uint8_t saw_digit, octets, ch;
+    uint8_t saw_digit, octets;
     uint8_t tmp[sizeof(ipv4_addr_t)], *tp;
+    const char *start = addr;
 
-    if ((result == NULL) || (addr == NULL)) {
+    if ((result == NULL) || (addr == NULL) || (addr_len == 0) ||
+        (addr_len > IPV4_ADDR_MAX_STR_LEN)) {
         return NULL;
     }
 
@@ -33,7 +37,8 @@ ipv4_addr_t *ipv4_addr_from_str(ipv4_addr_t *result, const char *addr)
     octets = 0;
     *(tp = tmp) = 0;
 
-    while ((ch = *addr++) != '\0') {
+    while ((size_t)(addr - start) < addr_len) {
+        uint8_t ch = *addr++;
         const char *pch;
 
         if ((pch = strchr(DEC, ch)) != NULL) {
@@ -74,5 +79,14 @@ ipv4_addr_t *ipv4_addr_from_str(ipv4_addr_t *result, const char *addr)
     return result;
 }
 
+ipv4_addr_t *ipv4_addr_from_str(ipv4_addr_t *result, const char *addr)
+{
+    if ((result == NULL) || (addr == NULL)) {
+        return NULL;
+    }
+
+    return ipv4_addr_from_buf(result, addr, strlen(addr));
+}
+
 
 /** @} */

tests/unittests/tests-ipv4_addr/tests-ipv4_addr.c

@@ -132,6 +132,34 @@ static void test_ipv4_addr_from_str__success2(void)
     TEST_ASSERT(ipv4_addr_equal(&a, &result));
 }
 
+static void test_ipv4_addr_from_buf__success(void)
+{
+    ipv4_addr_t a = { { 1, 1, 1, 1 } };
+    ipv4_addr_t result;
+
+    TEST_ASSERT_NOT_NULL(ipv4_addr_from_buf(&result, "1.1.1.1%tap0", 7));
+    TEST_ASSERT(ipv4_addr_equal(&a, &result));
+}
+
+static void test_ipv4_addr_from_buf__result_NULL(void)
+{
+    TEST_ASSERT_NULL(ipv4_addr_from_buf(NULL, "::", 2));
+}
+
+static void test_ipv4_addr_from_buf__illegal_chars(void)
+{
+    ipv4_addr_t result;
+
+    TEST_ASSERT_NULL(ipv4_addr_from_buf(&result, "1.1.1.1%tap0", 13));
+}
+
+static void test_ipv4_addr_from_buf__too_long_len(void)
+{
+    ipv4_addr_t result;
+
+    TEST_ASSERT_NULL(ipv4_addr_from_buf(&result, "1.1.1.1", IPV4_ADDR_MAX_STR_LEN + 1));
+}
+
 Test *tests_ipv4_addr_tests(void)
 {
     EMB_UNIT_TESTFIXTURES(fixtures) {
@@ -150,6 +178,10 @@ Test *tests_ipv4_addr_tests(void)
         new_TestFixture(test_ipv4_addr_from_str__result_NULL),
         new_TestFixture(test_ipv4_addr_from_str__success),
         new_TestFixture(test_ipv4_addr_from_str__success2),
+        new_TestFixture(test_ipv4_addr_from_buf__success),
+        new_TestFixture(test_ipv4_addr_from_buf__result_NULL),
+        new_TestFixture(test_ipv4_addr_from_buf__illegal_chars),
+        new_TestFixture(test_ipv4_addr_from_buf__too_long_len),
     };
 
     EMB_UNIT_TESTCALLER(ipv4_addr_tests, NULL, NULL, fixtures);