New upstream version 1.3.0~rc3upstream/1.3.0_rc3

1 files changed, 193 insertions, 0 deletions

diff --git a/src/utils/common/resolv.c b/src/utils/common/resolv.c
new file mode 100644
index 0000000..864a2a9
--- /dev/null
+++ b/src/utils/common/resolv.c
@@ -0,0 +1,193 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+#include "utils/common/resolv.h"
+
+#include <stdio.h>			// fopen
+#include <stdlib.h>			// free
+
+#include "common/lists.h"		// list
+#include "common/errcode.h"		// KNOT_ENOENT
+#include "utils/common/msg.h"		// DBG_NULL
+#include "utils/common/params.h"	// DEFAULT_IPV6_NAME
+
+#define RESOLV_FILE	"/etc/resolv.conf"
+
+server_t* parse_nameserver(const char *nameserver, const char *def_port)
+{
+	if (nameserver == NULL || def_port == NULL) {
+		DBG_NULL;
+		return NULL;
+	}
+
+	// OpenBSD notation: nameserver [address]:port
+	if (nameserver[0] == '[') {
+		char *addr, *port;
+
+		char   *start = (char *)nameserver + 1;
+		char   *end = index(nameserver, ']');
+		size_t addr_len = end - start;
+
+		// Missing closing bracket -> stop processing.
+		if (end == NULL) {
+			return NULL;
+		}
+
+		// Fill enclosed address.
+		addr = strndup(start, addr_len);
+
+		// Find possible port.
+		start += addr_len + 1;
+		if (strlen(start) > 0) {
+			// Check for colon separation.
+			if (*start != ':') {
+				free(addr);
+				return NULL;
+			}
+
+			size_t port_len = strlen(++start);
+
+			// Check port string length.
+			if (port_len == 0 || port_len >= sizeof(port)) {
+				free(addr);
+				return NULL;
+			}
+
+			// Fill port part.
+			port = strdup(start);
+		} else {
+			port = strdup(def_port);
+		}
+
+		// Create server structure.
+		server_t *server = server_create(addr, port);
+
+		free(addr);
+		free(port);
+
+		return server;
+	} else {
+		return server_create(nameserver, def_port);
+	}
+}
+
+static int get_resolv_nameservers(list *servers, const char *def_port)
+{
+	char	line[512];
+
+	// Open config file.
+	FILE *f = fopen(RESOLV_FILE, "r");
+
+	// Check correct open.
+	if (f == NULL) {
+		return KNOT_ENOENT;
+	}
+
+	// Read lines from config file.
+	while (fgets(line, sizeof(line), f) != NULL) {
+		size_t len;
+		char   *pos = line;
+		char   *option, *value;
+
+		// Find leading white characters.
+		len = strspn(pos, SEP_CHARS);
+		pos += len;
+
+		// Start of the first token.
+		option = pos;
+
+		// Find length of the token.
+		len = strcspn(pos, SEP_CHARS);
+		pos += len;
+
+		// Check if the token is not empty.
+		if (len <= 0) {
+			continue;
+		}
+
+		// Find separating white characters.
+		len = strspn(pos, SEP_CHARS);
+		pos += len;
+
+		// Check if there is a separation between tokens.
+		if (len <= 0) {
+			continue;
+		}
+
+		// Copy of the second token.
+		value = strndup(pos, strcspn(pos, SEP_CHARS));
+
+		// Process value with respect to option name.
+		if (strncmp(option, "nameserver", strlen("nameserver")) == 0) {
+			server_t *server;
+
+			server = parse_nameserver(value, def_port);
+
+			// If value is correct, add nameserver to the list.
+			if (server != NULL) {
+				add_tail(servers, (node *)server);
+			}
+		}
+
+		// Drop value string.
+		free(value);
+	}
+
+	// Close config file.
+	fclose(f);
+
+	// Return number of servers.
+	return list_size(servers);
+}
+
+int get_nameservers(list *servers, const char *def_port)
+{
+	if (servers == NULL || def_port == NULL) {
+		DBG_NULL;
+		return KNOT_EINVAL;
+	}
+
+	// Initialize list of servers.
+	init_list(servers);
+
+	// Read nameservers from resolv file.
+	int ret = get_resolv_nameservers(servers, def_port);
+
+	// If found nameservers or error.
+	if (ret != 0) {
+		return ret;
+	// If no nameservers.
+	} else {
+		server_t *server;
+
+		// Add default ipv6 nameservers.
+		server = server_create(DEFAULT_IPV6_NAME, def_port);
+
+		if (server != NULL) {
+			add_tail(servers, (node *)server);
+		}
+
+		// Add default ipv4 nameservers.
+		server = server_create(DEFAULT_IPV4_NAME, def_port);
+
+		if (server != NULL) {
+			add_tail(servers, (node *)server);
+		}
+
+		return list_size(servers);
+	}
+}