Adding upstream version 3.3.4.upstream/3.3.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 211 insertions, 0 deletions

diff --git a/src/utils/common/resolv.c b/src/utils/common/resolv.c
new file mode 100644
index 0000000..674a760
--- /dev/null
+++ b/src/utils/common/resolv.c
@@ -0,0 +1,211 @@
+/*  Copyright (C) 2023 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "utils/common/resolv.h"
+#include "utils/common/msg.h"
+#include "utils/common/params.h"
+#include "libknot/libknot.h"
+#include "contrib/ucw/lists.h"
+
+#define RESOLV_FILE	"/etc/resolv.conf"
+
+srv_info_t* parse_nameserver(const char *str, const char *def_port)
+{
+	char *host = NULL, *port = NULL;
+	const char *addr = NULL, *sep = NULL;
+	size_t addr_len = 0;
+	char separator = ':';
+
+	if (str == NULL || def_port == NULL) {
+		DBG_NULL;
+		return NULL;
+	}
+
+	const size_t str_len = strlen(str);
+	const char *str_end = str + str_len;
+
+	// UNIX socket path.
+	if (*str == '/') {
+		return srv_info_create(str, "UNIX");
+	// [address]:port notation.
+	} else if (*str == '[') {
+		addr = str + 1;
+		const char *addr_end = strchr(addr, ']');
+		// Missing closing bracket -> stop processing.
+		if (addr_end == NULL) {
+			return NULL;
+		}
+		addr_len = addr_end - addr;
+		str += 1 + addr_len + 1;
+	// Address@port notation.
+	} else if ((sep = strchr(str, '@')) != NULL) {
+		addr = str;
+		addr_len = sep - addr;
+		str += addr_len;
+		separator = '@';
+	// Address#port notation.
+	} else if ((sep = strchr(str, '#')) != NULL) {
+		addr = str;
+		addr_len = sep - addr;
+		str += addr_len;
+		separator = '#';
+	// IPv4:port notation.
+	} else if ((sep = strchr(str, ':')) != NULL) {
+		addr = str;
+		// Not IPv4 address -> no port.
+		if (strchr(sep + 1, ':') != NULL) {
+			addr_len = str_len;
+			str = str_end;
+		} else {
+			addr_len = sep - addr;
+			str += addr_len;
+		}
+	// No port specified.
+	} else {
+		addr = str;
+		addr_len = str_len;
+		str = str_end;
+	}
+
+	// Process port.
+	if (str < str_end) {
+		// Check port separator.
+		if (*str != separator) {
+			return NULL;
+		}
+		str++;
+
+		// Check for missing port.
+		if (str >= str_end) {
+			return NULL;
+		}
+
+		port = strdup(str);
+	} else {
+		port = strdup(def_port);
+	}
+
+	host = strndup(addr, addr_len);
+
+	// Create server structure.
+	srv_info_t *server = srv_info_create(host, port);
+
+	free(host);
+	free(port);
+
+	return server;
+}
+
+static size_t get_resolv_nameservers(list_t *servers, const char *def_port)
+{
+	char	line[512];
+
+	// Open config file.
+	FILE *f = fopen(RESOLV_FILE, "r");
+	if (f == NULL) {
+		return 0;
+	}
+
+	// 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) {
+			srv_info_t *server;
+
+			server = parse_nameserver(value, def_port);
+
+			// If value is correct, add nameserver to the list.
+			if (server != NULL) {
+				add_tail(servers, (node_t *)server);
+			}
+		}
+
+		// Drop value string.
+		free(value);
+	}
+
+	// Close config file.
+	fclose(f);
+
+	// Return number of servers.
+	return list_size(servers);
+}
+
+void get_nameservers(list_t *servers, const char *def_port)
+{
+	if (servers == NULL || def_port == NULL) {
+		DBG_NULL;
+		return;
+	}
+
+	// Initialize list of servers.
+	init_list(servers);
+
+	// Read nameservers from resolv file or use the default ones.
+	if (get_resolv_nameservers(servers, def_port) == 0) {
+		srv_info_t *server;
+
+		// Add default ipv6 nameservers.
+		server = srv_info_create(DEFAULT_IPV6_NAME, def_port);
+
+		if (server != NULL) {
+			add_tail(servers, (node_t *)server);
+		}
+
+		// Add default ipv4 nameservers.
+		server = srv_info_create(DEFAULT_IPV4_NAME, def_port);
+
+		if (server != NULL) {
+			add_tail(servers, (node_t *)server);
+		}
+	}
+}