--- /dev/null
+/*
+ * Copyright (c) 2018, JANET(UK)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of JANET(UK) nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <tr_inet_util.h>
+
+/**
+ * Determine whether a string is a valid address of a given family
+ *
+ * @param s string to check
+ * @param af address family (probably AF_INET or AF_INET6)
+ * @return 1 if string is a valid address in the given family, 0 if not, -1 on error (errno set)
+ */
+static int is_valid_address(int af, const char *s)
+{
+ unsigned char buf[sizeof(struct in6_addr)];
+
+ if (s == NULL)
+ return 0;
+ return inet_pton(af, s, buf);
+}
+
+/**
+ * Determine whether a string is a valid IPv4 address
+ * @param s string to validate
+ * @return 1 if a valid reference, 0 otherwise
+ */
+int is_valid_ipv4_address(const char *s)
+{
+ return is_valid_address(AF_INET, s);
+}
+
+/**
+ * Determine whether a string is a valid IPv6 address reference
+ *
+ * I.e., an IPv6 address in brackets
+ *
+ * @param s string to validate
+ * @return 1 if a valid reference, 0 otherwise
+ */
+int is_valid_ipv6_reference(const char *s)
+{
+ char *cpy;
+ size_t len;
+ int valid_ipv6;
+
+ /* check that it starts with an open bracket */
+ if (*s != '[')
+ return 0;
+
+ /* check that it ends with a close bracket */
+ len = strlen(s);
+ if (*(s+len-1) != ']')
+ return 0;
+
+ /* make a null-terminated copy of the string omitting the brackets */
+ cpy = strndup(s+1, len-2);
+ if (cpy == NULL)
+ return -1;
+
+ valid_ipv6 = is_valid_address(AF_INET6, cpy);
+ free(cpy);
+
+ return valid_ipv6;
+}
+
+static int is_valid_dns_char(char c)
+{
+ /* digits ok */
+ if ( ('0' <= c) && ('9' >= c))
+ return 1;
+
+ /* letters ok */
+ if ( (('a' <= c) && ('z' >= c))
+ || (('A' <= c) && ('Z' >= c)) )
+ return 1;
+
+ /* '-' ok */
+ if ('-' == c)
+ return 1;
+
+ /* everything else illegal */
+ return 0;
+}
+
+/**
+ * Helper to validate a DNS label
+ *
+ * Checks whether the string starting at s[start] and ending at s[end-1]
+ * is a valid DNS label.
+ *
+ * Does not check the length of the label.
+ *
+ * @param s
+ * @param start
+ * @param end
+ * @return
+ */
+static int is_valid_dns_label(const char *s, size_t start, size_t end)
+{
+ size_t ii;
+
+ /* Check that there is at least one character.
+ * Be careful - size_t is unsigned */
+ if (start >= end)
+ return 0;
+
+ /* must neither start nor end with '-' */
+ if ((s[start] == '-')
+ || s[end-1] == '-')
+ return 0;
+
+ /* make sure all characters are valid */
+ for (ii=start; ii<end; ii++) {
+ if (! is_valid_dns_char(s[ii]))
+ return 0;
+ }
+
+ return 1;
+}
+
+/**
+ * Determine whether a string is a valid DNS name
+ *
+ * Does not check the length of the name or of the indivdiual
+ * labels in it.
+ *
+ * @param s string to validate
+ * @return 1 if a valid DNS name, 0 otherwise
+ */
+int is_valid_dns_name(const char *s)
+{
+ size_t label_start;
+ size_t label_end;
+
+ /* reject some trivial cases */
+ if ((s == NULL)
+ || (*s == '\0'))
+ return 0;
+
+ /* Walk along with the end counter until we encounter a '.'. When that
+ * happens, we have a complete DNS label. Validate that, then set the start
+ * counter to one character past the end pointer, which will either be the
+ * next character in the DNS name or the null terminator. Since we stop as
+ * soon as the end counter reaches a null character, this will never refer
+ * to an invalid address. */
+ for (label_start = 0, label_end = 0;
+ s[label_end] != '\0';
+ label_end++) {
+ if (s[label_end] == '.') {
+ if (! is_valid_dns_label(s, label_start, label_end))
+ return 0;
+
+ label_start = label_end+1;
+ }
+ }
+
+ if (s[label_start] == '\0')
+ return 1; /* we must have ended on a '.' */
+
+ /* There was one more label to validate */
+ return is_valid_dns_label(s, label_start, label_end);
+}
+
+/**
+ * Validate a host string
+ *
+ * Valid formats:
+ * IPv4 address (dotted quad)
+ * IPv6 address in brackets (e.g., [::1])
+ * DNS hostname (labels made of alphanumerics or "-", separated by dots)
+ *
+ * @param s string to validate
+ * @return 1 if a valid host specification, 0 otherwise
+ */
+int is_valid_host(const char *s)
+{
+ if (is_valid_ipv4_address(s))
+ return 1;
+
+ if (is_valid_ipv6_reference(s))
+ return 1;
+
+ if (is_valid_dns_name(s))
+ return 1;
+
+ return 0;
+}
projects / trust_router.git / blobdiff