X-Git-Url: http://git.meshlink.io/?p=meshlink;a=blobdiff_plain;f=src%2Fconf.c;h=65ff2272ef68e50e293ad23cda5d4045315b3d7e;hp=dc5d2dc21f705b4d4e1e745523e495db9b75fb0e;hb=a5a8005b2d89712e124ab7295165a3e229abdad5;hpb=8c3105283ac53f8cc9cc4dde25957ec1cf6b53a0

diff --git a/src/conf.c b/src/conf.c
index dc5d2dc2..65ff2272 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -1,9 +1,6 @@
 /*
-    conf.c -- configuration code
-    Copyright (C) 1998 Robert van der Meulen
-                  1998-2005 Ivo Timmermans
-                  2000-2009 Guus Sliepen <guus@tinc-vpn.org>
-		  2000 Cris van Pelt
+    econf.c -- configuration code
+    Copyright (C) 2018 Guus Sliepen <guus@meshlink.io>
 
     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
@@ -21,434 +18,945 @@
 */
 
 #include "system.h"
+#include <assert.h>
+#include <sys/types.h>
+#include <utime.h>
 
-#include "avl_tree.h"
 #include "conf.h"
+#include "crypto.h"
 #include "logger.h"
-#include "netutl.h"				/* for str2address */
-#include "protocol.h"
-#include "utils.h"				/* for cp */
+#include "meshlink_internal.h"
 #include "xalloc.h"
+#include "packmsg.h"
 
-avl_tree_t *config_tree;
-
-int pinginterval = 0;			/* seconds between pings */
-int pingtimeout = 0;			/* seconds to wait for response */
-char *confbase = NULL;			/* directory in which all config files are */
-char *netname = NULL;			/* name of the vpn network */
-list_t *cmdline_conf = NULL;	/* global/host configuration values given at the command line */
+/// Generate a path to the main configuration file.
+static void make_main_path(meshlink_handle_t *mesh, const char *conf_subdir, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(path);
+	assert(len);
 
+	snprintf(path, len, "%s" SLASH "%s" SLASH "meshlink.conf", mesh->confbase, conf_subdir);
+}
 
-static int config_compare(const config_t *a, const config_t *b) {
-	int result;
+/// Generate a path to a host configuration file.
+static void make_host_path(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(name);
+	assert(path);
+	assert(len);
 
-	result = strcasecmp(a->variable, b->variable);
+	snprintf(path, len, "%s" SLASH "%s" SLASH "hosts" SLASH "%s", mesh->confbase, conf_subdir, name);
+}
 
-	if(result)
-		return result;
+/// Generate a path to an unused invitation file.
+static void make_invitation_path(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(name);
+	assert(path);
+	assert(len);
 
-	/* give priority to command line options */
-	result = !b->file - !a->file;
-	if (result)
-		return result;
+	snprintf(path, len, "%s" SLASH "%s" SLASH "invitations" SLASH "%s", mesh->confbase, conf_subdir, name);
+}
 
-	result = a->line - b->line;
+/// Generate a path to a used invitation file.
+static void make_used_invitation_path(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, char *path, size_t len) {
+	assert(conf_subdir);
+	assert(name);
+	assert(path);
+	assert(len);
 
-	if(result)
-		return result;
-	else
-		return a->file ? strcmp(a->file, b->file) : 0;
+	snprintf(path, len, "%s" SLASH "%s" SLASH "invitations" SLASH "%s.used", mesh->confbase, conf_subdir, name);
 }
 
-void init_configuration(avl_tree_t ** config_tree) {
-	*config_tree = avl_alloc_tree((avl_compare_t) config_compare, (avl_action_t) free_config);
-}
+/// Remove a directory recursively
+static void deltree(const char *dirname) {
+	assert(dirname);
 
-void exit_configuration(avl_tree_t ** config_tree) {
-	avl_delete_tree(*config_tree);
-	*config_tree = NULL;
-}
+	DIR *d = opendir(dirname);
+
+	if(d) {
+		struct dirent *ent;
+
+		while((ent = readdir(d))) {
+			if(ent->d_name[0] == '.') {
+				continue;
+			}
+
+			char filename[PATH_MAX];
+			snprintf(filename, sizeof(filename), "%s" SLASH "%s", dirname, ent->d_name);
 
-config_t *new_config(void) {
-	return xmalloc_and_zero(sizeof(config_t));
+			if(unlink(filename)) {
+				deltree(filename);
+			}
+		}
+
+		closedir(d);
+	}
+
+	rmdir(dirname);
 }
 
-void free_config(config_t *cfg) {
-	if(cfg->variable)
-		free(cfg->variable);
+static bool sync_path(const char *pathname) {
+	assert(pathname);
+
+	int fd = open(pathname, O_RDONLY);
 
-	if(cfg->value)
-		free(cfg->value);
+	if(fd < 0) {
+		logger(NULL, MESHLINK_ERROR, "Failed to open %s: %s\n", pathname, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(fsync(fd)) {
+		logger(NULL, MESHLINK_ERROR, "Failed to sync %s: %s\n", pathname, strerror(errno));
+		close(fd);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-	if(cfg->file)
-		free(cfg->file);
+	if(close(fd)) {
+		logger(NULL, MESHLINK_ERROR, "Failed to close %s: %s\n", pathname, strerror(errno));
+		close(fd);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-	free(cfg);
+	return true;
 }
 
-void config_add(avl_tree_t *config_tree, config_t *cfg) {
-	avl_insert(config_tree, cfg);
+/// Try decrypting the main configuration file from the given sub-directory.
+static bool main_config_decrypt(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(mesh->config_key);
+	assert(mesh->confbase);
+	assert(conf_subdir);
+
+	config_t config;
+
+	if(!main_config_read(mesh, conf_subdir, &config, mesh->config_key)) {
+		logger(mesh, MESHLINK_ERROR, "Could not read main configuration file");
+		return false;
+	}
+
+	packmsg_input_t in = {config.buf, config.len};
+
+	uint32_t version = packmsg_get_uint32(&in);
+	config_free(&config);
+
+	return version == MESHLINK_CONFIG_VERSION;
 }
 
-config_t *lookup_config(avl_tree_t *config_tree, char *variable) {
-	config_t cfg, *found;
+/// Create a fresh configuration directory
+bool config_init(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
 
-	cfg.variable = variable;
-	cfg.file = NULL;
-	cfg.line = 0;
+	if(!mesh->confbase) {
+		return true;
+	}
 
-	found = avl_search_closest_greater(config_tree, &cfg);
+	if(mkdir(mesh->confbase, 0700) && errno != EEXIST) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", mesh->confbase, strerror(errno));
+		return false;
+	}
+
+	char path[PATH_MAX];
 
-	if(!found)
-		return NULL;
+	// Create "current" sub-directory in the confbase
+	snprintf(path, sizeof(path), "%s" SLASH "%s", mesh->confbase, conf_subdir);
+	deltree(path);
 
-	if(strcasecmp(found->variable, variable))
-		return NULL;
+	if(mkdir(path, 0700)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
 
-	return found;
+	make_host_path(mesh, conf_subdir, "", path, sizeof(path));
+
+	if(mkdir(path, 0700)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
+
+	make_invitation_path(mesh, conf_subdir, "", path, sizeof(path));
+
+	if(mkdir(path, 0700)) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", path, strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-config_t *lookup_config_next(avl_tree_t *config_tree, const config_t *cfg) {
-	avl_node_t *node;
-	config_t *found;
+/// Wipe an existing configuration directory
+bool config_destroy(const char *confbase, const char *conf_subdir) {
+	assert(conf_subdir);
 
-	node = avl_search_node(config_tree, cfg);
+	if(!confbase) {
+		return false;
+	}
+
+	struct stat st;
 
-	if(node) {
-		if(node->next) {
-			found = node->next->data;
+	char path[PATH_MAX];
 
-			if(!strcasecmp(found->variable, cfg->variable))
-				return found;
+	// Check the presence of configuration base sub directory.
+	snprintf(path, sizeof(path), "%s" SLASH "%s", confbase, conf_subdir);
+
+	if(stat(path, &st)) {
+		if(errno == ENOENT) {
+			return true;
+		} else {
+			logger(NULL, MESHLINK_ERROR, "Cannot stat %s: %s\n", path, strerror(errno));
+			meshlink_errno = MESHLINK_ESTORAGE;
+			return false;
 		}
 	}
 
-	return NULL;
+	// Remove meshlink.conf
+	snprintf(path, sizeof(path), "%s" SLASH "%s" SLASH "meshlink.conf", confbase, conf_subdir);
+
+	if(unlink(path)) {
+		if(errno != ENOENT) {
+			logger(NULL, MESHLINK_ERROR, "Cannot delete %s: %s\n", path, strerror(errno));
+			meshlink_errno = MESHLINK_ESTORAGE;
+			return false;
+		}
+	}
+
+	snprintf(path, sizeof(path), "%s" SLASH "%s", confbase, conf_subdir);
+	deltree(path);
+	return true;
 }
 
-bool get_config_bool(const config_t *cfg, bool *result) {
-	if(!cfg)
+static bool copytree(const char *src_dir_name, const void *src_key, const char *dst_dir_name, const void *dst_key) {
+	assert(src_dir_name);
+	assert(dst_dir_name);
+
+	char src_filename[PATH_MAX];
+	char dst_filename[PATH_MAX];
+	struct dirent *ent;
+
+	DIR *src_dir = opendir(src_dir_name);
+
+	if(!src_dir) {
+		logger(NULL, MESHLINK_ERROR, "Could not open directory file %s\n", src_dir_name);
 		return false;
+	}
 
-	if(!strcasecmp(cfg->value, "yes")) {
-		*result = true;
-		return true;
-	} else if(!strcasecmp(cfg->value, "no")) {
-		*result = false;
-		return true;
+	// Delete if already exists and create a new destination directory
+	deltree(dst_dir_name);
+
+	if(mkdir(dst_dir_name, 0700)) {
+		logger(NULL, MESHLINK_ERROR, "Could not create directory %s\n", dst_filename);
+		return false;
 	}
 
-	logger(LOG_ERR, "\"yes\" or \"no\" expected for configuration variable %s in %s line %d",
-		   cfg->variable, cfg->file, cfg->line);
+	while((ent = readdir(src_dir))) {
+		if(ent->d_name[0] == '.') {
+			continue;
+		}
+
+		snprintf(dst_filename, sizeof(dst_filename), "%s" SLASH "%s", dst_dir_name, ent->d_name);
+		snprintf(src_filename, sizeof(src_filename), "%s" SLASH "%s", src_dir_name, ent->d_name);
+
+		if(ent->d_type == DT_DIR) {
+			if(!copytree(src_filename, src_key, dst_filename, dst_key)) {
+				logger(NULL, MESHLINK_ERROR, "Copying %s to %s failed\n", src_filename, dst_filename);
+				return false;
+			}
+
+			if(!sync_path(dst_filename)) {
+				return false;
+			}
+		} else if(ent->d_type == DT_REG) {
+			struct stat st;
+			config_t config;
+
+			if(stat(src_filename, &st)) {
+				logger(NULL, MESHLINK_ERROR, "Could not stat file `%s': %s\n", src_filename, strerror(errno));
+				return false;
+			}
+
+			FILE *f = fopen(src_filename, "r");
+
+			if(!f) {
+				logger(NULL, MESHLINK_ERROR, "Failed to open `%s': %s\n", src_filename, strerror(errno));
+				return false;
+			}
+
+			if(!config_read_file(NULL, f, &config, src_key)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to read `%s': %s\n", src_filename, strerror(errno));
+				fclose(f);
+				return false;
+			}
+
+			if(fclose(f)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to close `%s': %s\n", src_filename, strerror(errno));
+				config_free(&config);
+				return false;
+			}
+
+			f = fopen(dst_filename, "w");
+
+			if(!f) {
+				logger(NULL, MESHLINK_ERROR, "Failed to open `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				return false;
+			}
+
+			if(!config_write_file(NULL, f, &config, dst_key)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to write `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				fclose(f);
+				return false;
+			}
+
+			if(fclose(f)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to close `%s': %s", dst_filename, strerror(errno));
+				config_free(&config);
+				return false;
+			}
+
+			config_free(&config);
+
+			struct utimbuf times;
+			times.modtime = st.st_mtime;
+			times.actime = st.st_atime;
+
+			if(utime(dst_filename, &times)) {
+				logger(NULL, MESHLINK_ERROR, "Failed to utime `%s': %s", dst_filename, strerror(errno));
+				return false;
+			}
+		}
+	}
+
+	closedir(src_dir);
+	return true;
+}
+
+bool config_copy(meshlink_handle_t *mesh, const char *src_dir_name, const void *src_key, const char *dst_dir_name, const void *dst_key) {
+	assert(src_dir_name);
+	assert(dst_dir_name);
 
-	return false;
+	char src_filename[PATH_MAX];
+	char dst_filename[PATH_MAX];
+
+	snprintf(dst_filename, sizeof(dst_filename), "%s" SLASH "%s", mesh->confbase, dst_dir_name);
+	snprintf(src_filename, sizeof(src_filename), "%s" SLASH "%s", mesh->confbase, src_dir_name);
+
+	return copytree(src_filename, src_key, dst_filename, dst_key);
 }
 
-bool get_config_int(const config_t *cfg, int *result) {
-	if(!cfg)
+/// Check the presence of the main configuration file.
+bool main_config_exists(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
 		return false;
+	}
 
-	if(sscanf(cfg->value, "%d", result) == 1)
-		return true;
+	char path[PATH_MAX];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
+	return access(path, F_OK) == 0;
+}
+
+bool config_rename(meshlink_handle_t *mesh, const char *old_conf_subdir, const char *new_conf_subdir) {
+	assert(old_conf_subdir);
+	assert(new_conf_subdir);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char old_path[PATH_MAX];
+	char new_path[PATH_MAX];
 
-	logger(LOG_ERR, "Integer expected for configuration variable %s in %s line %d",
-		   cfg->variable, cfg->file, cfg->line);
+	snprintf(old_path, sizeof(old_path), "%s" SLASH "%s", mesh->confbase, old_conf_subdir);
+	snprintf(new_path, sizeof(new_path), "%s" SLASH "%s", mesh->confbase, new_conf_subdir);
 
-	return false;
+	return rename(old_path, new_path) == 0;
 }
 
-bool get_config_string(const config_t *cfg, char **result) {
-	if(!cfg)
+bool config_sync(meshlink_handle_t *mesh, const char *conf_subdir) {
+	assert(conf_subdir);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	snprintf(path, sizeof(path), "%s" SLASH "%s" SLASH "hosts", mesh->confbase, conf_subdir);
+
+	if(!sync_path(path)) {
 		return false;
+	}
+
+	snprintf(path, sizeof(path), "%s" SLASH "%s", mesh->confbase, conf_subdir);
 
-	*result = xstrdup(cfg->value);
+	if(!sync_path(path)) {
+		return false;
+	}
 
 	return true;
 }
 
-bool get_config_address(const config_t *cfg, struct addrinfo **result) {
-	struct addrinfo *ai;
-
-	if(!cfg)
+bool meshlink_confbase_exists(meshlink_handle_t *mesh) {
+	if(!mesh->confbase) {
 		return false;
+	}
 
-	ai = str2addrinfo(cfg->value, NULL, 0);
+	bool confbase_exists = false;
+	bool confbase_decryptable = false;
 
-	if(ai) {
-		*result = ai;
-		return true;
+	if(main_config_exists(mesh, "current")) {
+		confbase_exists = true;
+
+		if(mesh->config_key && main_config_decrypt(mesh, "current")) {
+			confbase_decryptable = true;
+		}
+	}
+
+	if(mesh->config_key && !confbase_decryptable && main_config_exists(mesh, "new")) {
+		confbase_exists = true;
+
+		if(main_config_decrypt(mesh, "new")) {
+			if(!config_destroy(mesh->confbase, "current")) {
+				return false;
+			}
+
+			if(!config_rename(mesh, "new", "current")) {
+				return false;
+			}
+
+			confbase_decryptable = true;
+		}
 	}
 
-	logger(LOG_ERR, "Hostname or IP address expected for configuration variable %s in %s line %d",
-		   cfg->variable, cfg->file, cfg->line);
+	if(mesh->config_key && !confbase_decryptable && main_config_exists(mesh, "old")) {
+		confbase_exists = true;
+
+		if(main_config_decrypt(mesh, "old")) {
+			if(!config_destroy(mesh->confbase, "current")) {
+				return false;
+			}
+
+			if(!config_rename(mesh, "old", "current")) {
+				return false;
+			}
+
+			confbase_decryptable = true;
+		}
+	}
 
-	return false;
+	// Cleanup if current is existing with old and new
+	if(confbase_exists && confbase_decryptable) {
+		config_destroy(mesh->confbase, "old");
+		config_destroy(mesh->confbase, "new");
+	}
+
+	return confbase_exists;
 }
 
-bool get_config_subnet(const config_t *cfg, subnet_t ** result) {
-	subnet_t subnet = {0};
+/// Lock the main configuration file.
+bool main_config_lock(meshlink_handle_t *mesh) {
+	if(!mesh->confbase) {
+		return true;
+	}
 
-	if(!cfg)
-		return false;
+	char path[PATH_MAX];
+	make_main_path(mesh, "current", path, sizeof(path));
 
-	if(!str2net(&subnet, cfg->value)) {
-		logger(LOG_ERR, "Subnet expected for configuration variable %s in %s line %d",
-			   cfg->variable, cfg->file, cfg->line);
+	mesh->conffile = fopen(path, "r");
+
+	if(!mesh->conffile) {
+		logger(NULL, MESHLINK_ERROR, "Cannot not open %s: %s\n", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
 		return false;
 	}
 
-	/* Teach newbies what subnets are... */
+#ifdef FD_CLOEXEC
+	fcntl(fileno(mesh->conffile), F_SETFD, FD_CLOEXEC);
+#endif
+
+#ifdef HAVE_MINGW
+	// TODO: use _locking()?
+#else
 
-	if(((subnet.type == SUBNET_IPV4)
-		&& !maskcheck(&subnet.net.ipv4.address, subnet.net.ipv4.prefixlength, sizeof(ipv4_t)))
-		|| ((subnet.type == SUBNET_IPV6)
-		&& !maskcheck(&subnet.net.ipv6.address, subnet.net.ipv6.prefixlength, sizeof(ipv6_t)))) {
-		logger(LOG_ERR, "Network address and prefix length do not match for configuration variable %s in %s line %d",
-			   cfg->variable, cfg->file, cfg->line);
+	if(flock(fileno(mesh->conffile), LOCK_EX | LOCK_NB) != 0) {
+		logger(NULL, MESHLINK_ERROR, "Cannot lock %s: %s\n", path, strerror(errno));
+		fclose(mesh->conffile);
+		mesh->conffile = NULL;
+		meshlink_errno = MESHLINK_EBUSY;
 		return false;
 	}
 
-	*(*result = new_subnet()) = subnet;
+#endif
 
 	return true;
 }
 
-/*
-  Read exactly one line and strip the trailing newline if any.
-*/
-static char *readline(FILE * fp, char *buf, size_t buflen) {
-	char *newline = NULL;
-	char *p;
+/// Unlock the main configuration file.
+void main_config_unlock(meshlink_handle_t *mesh) {
+	if(mesh->conffile) {
+		fclose(mesh->conffile);
+		mesh->conffile = NULL;
+	}
+}
 
-	if(feof(fp))
-		return NULL;
+/// Read a configuration file from a FILE handle.
+bool config_read_file(meshlink_handle_t *mesh, FILE *f, config_t *config, const void *key) {
+	assert(f);
 
-	p = fgets(buf, buflen, fp);
+	long len;
 
-	if(!p)
-		return NULL;
+	if(fseek(f, 0, SEEK_END) || !(len = ftell(f)) || fseek(f, 0, SEEK_SET)) {
+		logger(mesh, MESHLINK_ERROR, "Cannot get config file size: %s\n", strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-	newline = strchr(p, '\n');
+	uint8_t *buf = xmalloc(len);
 
-	if(!newline)
-		return buf;
+	if(fread(buf, len, 1, f) != 1) {
+		logger(mesh, MESHLINK_ERROR, "Cannot read config file: %s\n", strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-	*newline = '\0';	/* kill newline */
-	if(newline > p && newline[-1] == '\r')	/* and carriage return if necessary */
-		newline[-1] = '\0';
+	if(key) {
+		uint8_t *decrypted = xmalloc(len);
+		size_t decrypted_len = len;
+		chacha_poly1305_ctx_t *ctx = chacha_poly1305_init();
+		chacha_poly1305_set_key(ctx, key);
+
+		if(len > 12 && chacha_poly1305_decrypt_iv96(ctx, buf, buf + 12, len - 12, decrypted, &decrypted_len)) {
+			chacha_poly1305_exit(ctx);
+			free(buf);
+			config->buf = decrypted;
+			config->len = decrypted_len;
+			return true;
+		} else {
+			logger(mesh, MESHLINK_ERROR, "Cannot decrypt config file\n");
+			meshlink_errno = MESHLINK_ESTORAGE;
+			chacha_poly1305_exit(ctx);
+			free(decrypted);
+			free(buf);
+			return false;
+		}
+	}
 
-	return buf;
+	config->buf = buf;
+	config->len = len;
+
+	return true;
 }
 
-config_t *parse_config_line(char *line, const char *fname, int lineno) {
-	config_t *cfg;
-	int len;
-	char *variable, *value, *eol;
-	variable = value = line;
-
-	eol = line + strlen(line);
-	while(strchr("\t ", *--eol))
-		*eol = '\0';
-
-	len = strcspn(value, "\t =");
-	value += len;
-	value += strspn(value, "\t ");
-	if(*value == '=') {
-		value++;
-		value += strspn(value, "\t ");
-	}
-	variable[len] = '\0';
-
-	if(!*value) {
-		const char err[] = "No value for variable";
-		if (fname)
-			logger(LOG_ERR, "%s `%s' on line %d while reading config file %s",
-				err, variable, lineno, fname);
-		else
-			logger(LOG_ERR, "%s `%s' in command line option %d",
-				err, variable, lineno);
-		return NULL;
-	}
-
-	cfg = new_config();
-	cfg->variable = xstrdup(variable);
-	cfg->value = xstrdup(value);
-	cfg->file = fname ? xstrdup(fname) : NULL;
-	cfg->line = lineno;
-
-	return cfg;
+/// Write a configuration file to a FILE handle.
+bool config_write_file(meshlink_handle_t *mesh, FILE *f, const config_t *config, const void *key) {
+	assert(f);
+
+	if(key) {
+		uint8_t buf[config->len + 16];
+		size_t len = sizeof(buf);
+		uint8_t seqbuf[12];
+		randomize(&seqbuf, sizeof(seqbuf));
+		chacha_poly1305_ctx_t *ctx = chacha_poly1305_init();
+		chacha_poly1305_set_key(ctx, key);
+		bool success = false;
+
+		if(chacha_poly1305_encrypt_iv96(ctx, seqbuf, config->buf, config->len, buf, &len)) {
+			success = fwrite(seqbuf, sizeof(seqbuf), 1, f) == 1 && fwrite(buf, len, 1, f) == 1;
+		} else {
+			logger(mesh, MESHLINK_ERROR, "Cannot encrypt config file\n");
+			meshlink_errno = MESHLINK_ESTORAGE;
+		}
+
+		chacha_poly1305_exit(ctx);
+		return success;
+	}
+
+	if(fwrite(config->buf, config->len, 1, f) != 1) {
+		logger(mesh, MESHLINK_ERROR, "Cannot write config file: %s", strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
+
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync file: %s\n", strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-/*
-  Parse a configuration file and put the results in the configuration tree
-  starting at *base.
-*/
-bool read_config_file(avl_tree_t *config_tree, const char *fname) {
-	FILE *fp;
-	char buffer[MAX_STRING_SIZE];
-	char *line;
-	int lineno = 0;
-	bool ignore = false;
-	config_t *cfg;
-	bool result = false;
+/// Free resources of a loaded configuration file.
+void config_free(config_t *config) {
+	assert(!config->len || config->buf);
+
+	free((uint8_t *)config->buf);
+	config->buf = NULL;
+	config->len = 0;
+}
 
-	fp = fopen(fname, "r");
+/// Check the presence of a host configuration file.
+bool config_exists(meshlink_handle_t *mesh, const char *conf_subdir, const char *name) {
+	assert(conf_subdir);
 
-	if(!fp) {
-		logger(LOG_ERR, "Cannot open config file %s: %s", fname, strerror(errno));
+	if(!mesh->confbase) {
 		return false;
 	}
 
-	for(;;) {
-		line = readline(fp, buffer, sizeof buffer);
+	char path[PATH_MAX];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
 
-		if(!line) {
-			if(feof(fp))
-				result = true;
-			break;
-		}
+	return access(path, F_OK) == 0;
+}
 
-		lineno++;
+/// Read a host configuration file.
+bool config_read(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, config_t *config, void *key) {
+	assert(conf_subdir);
 
-		if(!*line || *line == '#')
-			continue;
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
+
+	FILE *f = fopen(path, "r");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	if(!config_read_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to read `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	fclose(f);
+
+	return true;
+}
+
+bool config_scan_all(meshlink_handle_t *mesh, const char *conf_subdir, const char *conf_type, config_scan_action_t action, void *arg) {
+	assert(conf_subdir);
+	assert(conf_type);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	DIR *dir;
+	struct dirent *ent;
+	char dname[PATH_MAX];
+	snprintf(dname, sizeof(dname), "%s" SLASH "%s" SLASH "%s", mesh->confbase, conf_subdir, conf_type);
+
+	dir = opendir(dname);
+
+	if(!dir) {
+		logger(mesh, MESHLINK_ERROR, "Could not open %s: %s", dname, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-		if(ignore) {
-			if(!strncmp(line, "-----END", 8))
-				ignore = false;
+	while((ent = readdir(dir))) {
+		if(ent->d_name[0] == '.') {
 			continue;
 		}
-		
-		if(!strncmp(line, "-----BEGIN", 10)) {
-			ignore = true;
-			continue;
+
+		if(!action(mesh, ent->d_name, arg)) {
+			closedir(dir);
+			return false;
 		}
+	}
+
+	closedir(dir);
+	return true;
+}
+
+/// Write a host configuration file.
+bool config_write(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, const config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(name);
+	assert(config);
 
-		cfg = parse_config_line(line, fname, lineno);
-		if (!cfg)
-			break;
-		config_add(config_tree, cfg);
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	char tmp_path[PATH_MAX + 4];
+	make_host_path(mesh, conf_subdir, name, path, sizeof(path));
+	snprintf(tmp_path, sizeof(tmp_path), "%s.tmp", path);
+
+	FILE *f = fopen(tmp_path, "w");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	if(!config_write_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to write `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
 	}
 
-	fclose(fp);
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
 
-	return result;
+	if(rename(tmp_path, path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to rename `%s' to `%s': %s", tmp_path, path, strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-bool read_server_config() {
-	list_node_t *node, *next;
-	char *fname;
-	bool x;
-
-	for(node = cmdline_conf->tail; node; node = next) {
-		config_t *cfg = (config_t *)node->data;
-		next = node->prev;
-		if (!strchr(cfg->variable, '.')) {
-			config_add(config_tree, cfg);
-			node->data = NULL;
-			list_unlink_node(cmdline_conf, node);
-		}
+/// Read the main configuration file.
+bool main_config_read(meshlink_handle_t *mesh, const char *conf_subdir, config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return false;
 	}
 
-	xasprintf(&fname, "%s/tinc.conf", confbase);
-	x = read_config_file(config_tree, fname);
+	char path[PATH_MAX];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
 
-	if(!x) {				/* System error: complain */
-		logger(LOG_ERR, "Failed to read `%s': %s", fname, strerror(errno));
+	FILE *f = fopen(path, "r");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
 	}
 
-	free(fname);
+	if(!config_read_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to read `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
 
-	return x;
+	fclose(f);
+
+	return true;
 }
 
-FILE *ask_and_open(const char *filename, const char *what) {
-	FILE *r;
-	char *directory;
-	char line[PATH_MAX];
-	const char *fn;
-
-	/* Check stdin and stdout */
-	if(!isatty(0) || !isatty(1)) {
-		/* Argh, they are running us from a script or something.  Write
-		   the files to the current directory and let them burn in hell
-		   for ever. */
-		fn = filename;
-	} else {
-		/* Ask for a file and/or directory name. */
-		fprintf(stdout, "Please enter a file to save %s to [%s]: ",
-				what, filename);
-		fflush(stdout);
-
-		fn = readline(stdin, line, sizeof line);
-
-		if(!fn) {
-			fprintf(stderr, "Error while reading stdin: %s\n",
-					strerror(errno));
-			return NULL;
+/// Write the main configuration file.
+bool main_config_write(meshlink_handle_t *mesh, const char *conf_subdir, const config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	char tmp_path[PATH_MAX + 4];
+	make_main_path(mesh, conf_subdir, path, sizeof(path));
+	snprintf(tmp_path, sizeof(tmp_path), "%s.tmp", path);
+
+	FILE *f = fopen(tmp_path, "w");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	if(!config_write_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to write `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", tmp_path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(rename(tmp_path, path)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to rename `%s' to `%s': %s", tmp_path, path, strerror(errno));
+		fclose(f);
+		return false;
+	}
+
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", tmp_path, strerror(errno));
+		return false;
+	}
+
+	return true;
+}
+
+/// Read an invitation file from the confbase sub-directory, and immediately delete it.
+bool invitation_read(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(name);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return false;
+	}
+
+	char path[PATH_MAX];
+	char used_path[PATH_MAX];
+	make_invitation_path(mesh, conf_subdir, name, path, sizeof(path));
+	make_used_invitation_path(mesh, conf_subdir, name, used_path, sizeof(used_path));
+
+	// Atomically rename the invitation file
+	if(rename(path, used_path)) {
+		if(errno == ENOENT) {
+			logger(mesh, MESHLINK_ERROR, "Peer tried to use non-existing invitation %s\n", name);
+		} else {
+			logger(mesh, MESHLINK_ERROR, "Error trying to rename invitation %s\n", name);
 		}
 
-		if(!strlen(fn))
-			/* User just pressed enter. */
-			fn = filename;
+		return false;
 	}
 
-#ifdef HAVE_MINGW
-	if(fn[0] != '\\' && fn[0] != '/' && !strchr(fn, ':')) {
-#else
-	if(fn[0] != '/') {
-#endif
-		/* The directory is a relative path or a filename. */
-		char *p;
+	FILE *f = fopen(used_path, "r");
+
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	// Check the timestamp
+	struct stat st;
+
+	if(fstat(fileno(f), &st)) {
+		logger(mesh, MESHLINK_ERROR, "Could not stat invitation file %s\n", name);
+		fclose(f);
+		unlink(used_path);
+		return false;
+	}
+
+	if(mesh->loop.now.tv_sec > st.st_mtime + mesh->invitation_timeout) {
+		logger(mesh, MESHLINK_ERROR, "Peer tried to use an outdated invitation file %s\n", name);
+		fclose(f);
+		unlink(used_path);
+		return false;
+	}
+
+	if(!config_read_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to read `%s': %s", path, strerror(errno));
+		fclose(f);
+		unlink(used_path);
+		return false;
+	}
+
+	fclose(f);
 
-		directory = get_current_dir_name();
-		xasprintf(&p, "%s/%s", directory, fn);
-		free(directory);
-		fn = p;
+	unlink(used_path);
+	return true;
+}
+
+/// Write an invitation file.
+bool invitation_write(meshlink_handle_t *mesh, const char *conf_subdir, const char *name, const config_t *config, void *key) {
+	assert(conf_subdir);
+	assert(name);
+	assert(config);
+
+	if(!mesh->confbase) {
+		return false;
 	}
 
-	umask(0077);				/* Disallow everything for group and other */
+	char path[PATH_MAX];
+	make_invitation_path(mesh, conf_subdir, name, path, sizeof(path));
+
+	FILE *f = fopen(path, "w");
 
-	/* Open it first to keep the inode busy */
+	if(!f) {
+		logger(mesh, MESHLINK_ERROR, "Failed to open `%s': %s", path, strerror(errno));
+		return false;
+	}
 
-	r = fopen(fn, "r+") ?: fopen(fn, "w+");
+	if(!config_write_file(mesh, f, config, key)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to write `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
+	}
 
-	if(!r) {
-		fprintf(stderr, "Error opening file `%s': %s\n",
-				fn, strerror(errno));
-		return NULL;
+	if(fsync(fileno(f))) {
+		logger(mesh, MESHLINK_ERROR, "Failed to sync `%s': %s", path, strerror(errno));
+		fclose(f);
+		return false;
 	}
 
-	return r;
+	if(fclose(f)) {
+		logger(mesh, MESHLINK_ERROR, "Failed to close `%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	return true;
 }
 
-bool disable_old_keys(FILE *f) {
-	char buf[100];
-	long pos;
-	bool disabled = false;
-
-	rewind(f);
-	pos = ftell(f);
-
-	while(fgets(buf, sizeof buf, f)) {
-		if(!strncmp(buf, "-----BEGIN RSA", 14)) {	
-			buf[11] = 'O';
-			buf[12] = 'L';
-			buf[13] = 'D';
-			fseek(f, pos, SEEK_SET);
-			fputs(buf, f);
-			disabled = true;
+/// Purge old invitation files
+size_t invitation_purge_old(meshlink_handle_t *mesh, time_t deadline) {
+	if(!mesh->confbase) {
+		return true;
+	}
+
+	char path[PATH_MAX];
+	make_invitation_path(mesh, "current", "", path, sizeof(path));
+
+	DIR *dir = opendir(path);
+
+	if(!dir) {
+		logger(mesh, MESHLINK_DEBUG, "Could not read directory %s: %s\n", path, strerror(errno));
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return 0;
+	}
+
+	errno = 0;
+	size_t count = 0;
+	struct dirent *ent;
+
+	while((ent = readdir(dir))) {
+		if(strlen(ent->d_name) != 24) {
+			continue;
 		}
-		else if(!strncmp(buf, "-----END RSA", 12)) {	
-			buf[ 9] = 'O';
-			buf[10] = 'L';
-			buf[11] = 'D';
-			fseek(f, pos, SEEK_SET);
-			fputs(buf, f);
-			disabled = true;
+
+		char invname[PATH_MAX];
+		struct stat st;
+
+		if(snprintf(invname, sizeof(invname), "%s" SLASH "%s", path, ent->d_name) >= PATH_MAX) {
+			logger(mesh, MESHLINK_DEBUG, "Filename too long: %s" SLASH "%s", path, ent->d_name);
+			continue;
+		}
+
+		if(!stat(invname, &st)) {
+			if(mesh->invitation_key && deadline < st.st_mtime) {
+				count++;
+			} else {
+				unlink(invname);
+			}
+		} else {
+			logger(mesh, MESHLINK_DEBUG, "Could not stat %s: %s\n", invname, strerror(errno));
+			errno = 0;
 		}
-		pos = ftell(f);
 	}
 
-	return disabled;
+	if(errno) {
+		logger(mesh, MESHLINK_DEBUG, "Error while reading directory %s: %s\n", path, strerror(errno));
+		closedir(dir);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return 0;
+	}
+
+	closedir(dir);
+
+	return count;
 }