/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <arpa/inet.h>
#include <resolv.h>
#include <linux/if.h>
#include "resolved.h"
#include "event-util.h"
#include "network-util.h"
#include "sd-dhcp-lease.h"
#include "dhcp-lease-internal.h"
#include "network-internal.h"
#include "conf-parser.h"
static int set_fallback_dns(Manager *m, const char *string) {
char *word, *state;
size_t length;
int r;
assert(m);
assert(string);
FOREACH_WORD_QUOTED(word, length, string, state) {
_cleanup_free_ Address *address = NULL;
Address *tail;
_cleanup_free_ char *addrstr = NULL;
address = new0(Address, 1);
if (!address)
return -ENOMEM;
addrstr = strndup(word, length);
if (!addrstr)
return -ENOMEM;
r = net_parse_inaddr(addrstr, &address->family, &address->in_addr);
if (r < 0) {
log_debug("Ignoring invalid DNS address '%s'", addrstr);
continue;
}
LIST_FIND_TAIL(addresses, m->fallback_dns, tail);
LIST_INSERT_AFTER(addresses, m->fallback_dns, tail, address);
address = NULL;
}
return 0;
}
int config_parse_dnsv(
const char *unit,
const char *filename,
unsigned line,
const char *section,
unsigned section_line,
const char *lvalue,
int ltype,
const char *rvalue,
void *data,
void *userdata) {
Manager *m = userdata;
Address *address;
assert(filename);
assert(lvalue);
assert(rvalue);
assert(m);
while ((address = m->fallback_dns)) {
LIST_REMOVE(addresses, m->fallback_dns, address);
free(address);
}
set_fallback_dns(m, rvalue);
return 0;
}
static int manager_parse_config_file(Manager *m) {
static const char fn[] = "/etc/systemd/resolved.conf";
_cleanup_fclose_ FILE *f = NULL;
int r;
assert(m);
f = fopen(fn, "re");
if (!f) {
if (errno == ENOENT)
return 0;
log_warning("Failed to open configuration file %s: %m", fn);
return -errno;
}
r = config_parse(NULL, fn, f, "Resolve\0", config_item_perf_lookup,
(void*) resolved_gperf_lookup, false, false, m);
if (r < 0)
log_warning("Failed to parse configuration file: %s", strerror(-r));
return r;
}
int manager_new(Manager **ret) {
_cleanup_manager_free_ Manager *m = NULL;
int r;
m = new0(Manager, 1);
if (!m)
return -ENOMEM;
r = set_fallback_dns(m, DNS_SERVERS);
if (r < 0)
return r;
r = manager_parse_config_file(m);
if (r < 0)
return r;
r = sd_event_default(&m->event);
if (r < 0)
return r;
sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
sd_event_set_watchdog(m->event, true);
*ret = m;
m = NULL;
return 0;
}
void manager_free(Manager *m) {
Address *address;
if (!m)
return;
sd_event_unref(m->event);
while ((address = m->fallback_dns)) {
LIST_REMOVE(addresses, m->fallback_dns, address);
free(address);
}
free(m);
}
static void append_dns(FILE *f, void *dns, unsigned char family, unsigned *count) {
char buf[INET6_ADDRSTRLEN];
const char *address;
assert(f);
assert(dns);
assert(count);
address = inet_ntop(family, dns, buf, INET6_ADDRSTRLEN);
if (!address) {
log_warning("Invalid DNS address. Ignoring.");
return;
}
if (*count == MAXNS)
fputs("# Too many DNS servers configured, the following entries "
"may be ignored\n", f);
fprintf(f, "nameserver %s\n", address);
(*count) ++;
}
int manager_update_resolv_conf(Manager *m) {
const char *path = "/run/systemd/resolve/resolv.conf";
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ unsigned *indices = NULL;
Address *address;
unsigned count = 0;
int n, r, i;
assert(m);
r = fopen_temporary(path, &f, &temp_path);
if (r < 0)
return r;
fchmod(fileno(f), 0644);
fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n"
"# Third party programs must not access this file directly, but\n"
"# only through the symlink at /etc/resolv.conf. To manage\n"
"# resolv.conf(5) in a different way, replace the symlink by a\n"
"# static file or a different symlink.\n\n", f);
n = sd_network_get_ifindices(&indices);
if (n < 0)
n = 0;
for (i = 0; i < n; i++) {
_cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
struct in_addr *nameservers;
struct in6_addr *nameservers6;
size_t nameservers_size;
r = sd_network_dhcp_use_dns(indices[i]);
if (r > 0) {
r = sd_network_get_dhcp_lease(indices[i], &lease);
if (r >= 0) {
r = sd_dhcp_lease_get_dns(lease, &nameservers, &nameservers_size);
if (r >= 0) {
unsigned j;
for (j = 0; j < nameservers_size; j++)
append_dns(f, &nameservers[j], AF_INET, &count);
}
}
}
r = sd_network_get_dns(indices[i], &nameservers, &nameservers_size);
if (r >= 0) {
unsigned j;
for (j = 0; j < nameservers_size; j++)
append_dns(f, &nameservers[j], AF_INET, &count);
free(nameservers);
}
r = sd_network_get_dns6(indices[i], &nameservers6, &nameservers_size);
if (r >= 0) {
unsigned j;
for (j = 0; j < nameservers_size; j++)
append_dns(f, &nameservers6[j], AF_INET6, &count);
free(nameservers6);
}
}
LIST_FOREACH(addresses, address, m->fallback_dns)
append_dns(f, &address->in_addr, address->family, &count);
fflush(f);
if (ferror(f) || rename(temp_path, path) < 0) {
r = -errno;
unlink(path);
unlink(temp_path);
return r;
}
return 0;
}
static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents,
void *userdata) {
Manager *m = userdata;
int r;
assert(m);
r = manager_update_resolv_conf(m);
if (r < 0)
log_warning("Could not update resolv.conf: %s", strerror(-r));
sd_network_monitor_flush(m->network_monitor);
return 0;
}
int manager_network_monitor_listen(Manager *m) {
_cleanup_event_source_unref_ sd_event_source *event_source = NULL;
_cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL;
int r, fd, events;
r = sd_network_monitor_new(NULL, &monitor);
if (r < 0)
return r;
fd = sd_network_monitor_get_fd(monitor);
if (fd < 0)
return fd;
events = sd_network_monitor_get_events(monitor);
if (events < 0)
return events;
r = sd_event_add_io(m->event, &event_source, fd, events,
&manager_network_event_handler, m);
if (r < 0)
return r;
m->network_monitor = monitor;
m->network_event_source = event_source;
monitor = NULL;
event_source = NULL;
return 0;
}