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Systemd/src/resolve/resolved-manager.c

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/*-*- 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 <sys/ioctl.h>
#include <sys/poll.h>
#include <netinet/in.h>
#include "rtnl-util.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"
#include "socket-util.h"
#include "resolved.h"
#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) {
Manager *m = userdata;
uint16_t type;
Link *l;
int ifindex, r;
assert(rtnl);
assert(m);
assert(mm);
r = sd_rtnl_message_get_type(mm, &type);
if (r < 0)
goto fail;
r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
if (r < 0)
goto fail;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
switch (type) {
case RTM_NEWLINK:
if (!l) {
log_debug("Found link %i", ifindex);
r = link_new(m, &l, ifindex);
if (r < 0)
goto fail;
}
r = link_update_rtnl(l, mm);
if (r < 0)
goto fail;
break;
case RTM_DELLINK:
if (l) {
log_debug("Removing link %i", l->ifindex);
link_free(l);
}
break;
}
return 0;
fail:
log_warning("Failed to process RTNL link message: %s", strerror(-r));
return 0;
}
static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) {
Manager *m = userdata;
union in_addr_union address;
unsigned char family;
uint16_t type;
int r, ifindex;
LinkAddress *a;
Link *l;
assert(rtnl);
assert(mm);
assert(m);
r = sd_rtnl_message_get_type(mm, &type);
if (r < 0)
goto fail;
r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
if (r < 0)
goto fail;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (!l)
return 0;
r = sd_rtnl_message_addr_get_family(mm, &family);
if (r < 0)
goto fail;
switch (family) {
case AF_INET:
r = sd_rtnl_message_read_in_addr(mm, IFA_LOCAL, &address.in);
if (r < 0) {
r = sd_rtnl_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
if (r < 0)
goto fail;
}
break;
case AF_INET6:
r = sd_rtnl_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
if (r < 0) {
r = sd_rtnl_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
if (r < 0)
goto fail;
}
break;
default:
return 0;
}
a = link_find_address(l, family, &address);
switch (type) {
case RTM_NEWADDR:
if (!a) {
r = link_address_new(l, &a, family, &address);
if (r < 0)
return r;
}
r = link_address_update_rtnl(a, mm);
if (r < 0)
return r;
break;
case RTM_DELADDR:
if (a)
link_address_free(a);
break;
}
return 0;
fail:
log_warning("Failed to process RTNL address message: %s", strerror(-r));
return 0;
}
static int manager_rtnl_listen(Manager *m) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL;
sd_rtnl_message *i;
int r;
assert(m);
/* First, subscibe to interfaces coming and going */
r = sd_rtnl_open(&m->rtnl, 3, RTNLGRP_LINK, RTNLGRP_IPV4_IFADDR, RTNLGRP_IPV6_IFADDR);
if (r < 0)
return r;
r = sd_rtnl_attach_event(m->rtnl, m->event, 0);
if (r < 0)
return r;
r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m);
if (r < 0)
return r;
r = sd_rtnl_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m);
if (r < 0)
return r;
r = sd_rtnl_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m);
if (r < 0)
return r;
r = sd_rtnl_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m);
if (r < 0)
return r;
/* Then, enumerate all links */
r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
if (r < 0)
return r;
r = sd_rtnl_message_request_dump(req, true);
if (r < 0)
return r;
r = sd_rtnl_call(m->rtnl, req, 0, &reply);
if (r < 0)
return r;
for (i = reply; i; i = sd_rtnl_message_next(i)) {
r = manager_process_link(m->rtnl, i, m);
if (r < 0)
return r;
}
req = sd_rtnl_message_unref(req);
reply = sd_rtnl_message_unref(reply);
/* Finally, enumerate all addresses, too */
r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
if (r < 0)
return r;
r = sd_rtnl_message_request_dump(req, true);
if (r < 0)
return r;
r = sd_rtnl_call(m->rtnl, req, 0, &reply);
if (r < 0)
return r;
for (i = reply; i; i = sd_rtnl_message_next(i)) {
r = manager_process_address(m->rtnl, i, m);
if (r < 0)
return r;
}
return r;
}
static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
Iterator i;
Link *l;
int r;
assert(m);
sd_network_monitor_flush(m->network_monitor);
HASHMAP_FOREACH(l, m->links, i) {
r = link_update_monitor(l);
if (r < 0)
log_warning("Failed to update monitor information for %i: %s", l->ifindex, strerror(-r));
}
r = manager_write_resolv_conf(m);
if (r < 0)
log_warning("Could not update resolv.conf: %s", strerror(-r));
return 0;
}
static int manager_network_monitor_listen(Manager *m) {
int r, fd, events;
assert(m);
r = sd_network_monitor_new(NULL, &m->network_monitor);
if (r < 0)
return r;
fd = sd_network_monitor_get_fd(m->network_monitor);
if (fd < 0)
return fd;
events = sd_network_monitor_get_events(m->network_monitor);
if (events < 0)
return events;
r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
if (r < 0)
return r;
return 0;
}
static int parse_dns_server_string(Manager *m, const char *string) {
char *word, *state;
size_t length;
int r;
assert(m);
assert(string);
FOREACH_WORD_QUOTED(word, length, string, state) {
char buffer[length+1];
unsigned family;
union in_addr_union addr;
memcpy(buffer, word, length);
buffer[length] = 0;
r = in_addr_from_string_auto(buffer, &family, &addr);
if (r < 0) {
log_warning("Ignoring invalid DNS address '%s'", buffer);
continue;
}
/* filter out duplicates */
if (manager_find_dns_server(m, family, &addr))
continue;
r = dns_server_new(m, NULL, DNS_SERVER_SYSTEM, NULL, family, &addr);
if (r < 0)
return r;
}
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;
int r;
assert(filename);
assert(lvalue);
assert(rvalue);
assert(m);
/* Empty assignment means clear the list */
if (isempty(rvalue)) {
while (m->dns_servers)
dns_server_free(m->dns_servers);
return 0;
}
r = parse_dns_server_string(m, rvalue);
if (r < 0) {
log_error("Failed to parse DNS server string");
return r;
}
return 0;
}
int manager_parse_config_file(Manager *m) {
int r;
assert(m);
r = config_parse(NULL, "/etc/systemd/resolved.conf", NULL,
"Resolve\0",
config_item_perf_lookup, resolved_gperf_lookup,
false, false, m);
if (r < 0)
log_warning("Failed to parse configuration file: %s", strerror(-r));
return 0;
}
int manager_new(Manager **ret) {
_cleanup_(manager_freep) Manager *m = NULL;
int r;
assert(ret);
m = new0(Manager, 1);
if (!m)
return -ENOMEM;
m->dns_ipv4_fd = m->dns_ipv6_fd = -1;
r = parse_dns_server_string(m, /* "172.31.0.125 2001:4860:4860::8888 2001:4860:4860::8889" */ DNS_SERVERS);
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);
r = dns_scope_new(m, &m->unicast_scope, DNS_SCOPE_DNS);
if (r < 0)
return r;
r = manager_network_monitor_listen(m);
if (r < 0)
return r;
r = manager_rtnl_listen(m);
if (r < 0)
return r;
r = manager_connect_bus(m);
if (r < 0)
return r;
*ret = m;
m = NULL;
return 0;
}
Manager *manager_free(Manager *m) {
Link *l;
if (!m)
return NULL;
while (m->dns_queries)
dns_query_free(m->dns_queries);
hashmap_free(m->dns_query_transactions);
while ((l = hashmap_first(m->links)))
link_free(l);
hashmap_free(m->links);
dns_scope_free(m->unicast_scope);
while (m->dns_servers)
dns_server_free(m->dns_servers);
sd_event_source_unref(m->network_event_source);
sd_network_monitor_unref(m->network_monitor);
sd_event_source_unref(m->dns_ipv4_event_source);
sd_event_source_unref(m->dns_ipv6_event_source);
safe_close(m->dns_ipv4_fd);
safe_close(m->dns_ipv6_fd);
sd_event_source_unref(m->bus_retry_event_source);
sd_bus_unref(m->bus);
sd_event_unref(m->event);
free(m);
return NULL;
}
static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) {
_cleanup_free_ char *t = NULL;
int r;
assert(s);
assert(f);
assert(count);
r = in_addr_to_string(s->family, &s->address, &t);
if (r < 0) {
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", t);
(*count) ++;
}
int manager_write_resolv_conf(Manager *m) {
const char *path = "/run/systemd/resolve/resolv.conf";
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
unsigned count = 0;
DnsServer *s;
Iterator i;
Link *l;
int r;
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);
HASHMAP_FOREACH(l, m->links, i) {
LIST_FOREACH(servers, s, l->link_dns_servers)
write_resolve_conf_server(s, f, &count);
LIST_FOREACH(servers, s, l->dhcp_dns_servers)
write_resolve_conf_server(s, f, &count);
}
LIST_FOREACH(servers, s, m->dns_servers)
write_resolve_conf_server(s, f, &count);
r = fflush_and_check(f);
if (r < 0)
goto fail;
if (rename(temp_path, path) < 0) {
r = -errno;
goto fail;
}
return 0;
fail:
unlink(path);
unlink(temp_path);
return r;
}
int manager_dns_ipv4_recv(Manager *m, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
struct msghdr mh = {};
int fd, ms = 0, r;
struct iovec iov;
ssize_t l;
assert(m);
assert(ret);
fd = manager_dns_ipv4_fd(m);
if (fd < 0)
return fd;
r = ioctl(fd, FIONREAD, &ms);
if (r < 0)
return -errno;
if (ms < 0)
return -EIO;
r = dns_packet_new(&p, ms);
if (r < 0)
return r;
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->allocated;
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
l = recvmsg(fd, &mh, 0);
if (l < 0) {
if (errno == EAGAIN)
return 0;
return -errno;
}
if (l <= 0)
return -EIO;
p->size = (size_t) l;
*ret = p;
p = NULL;
return 1;
}
int manager_dns_ipv6_recv(Manager *m, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
struct msghdr mh = {};
struct iovec iov;
int fd, ms = 0, r;
ssize_t l;
assert(m);
assert(ret);
fd = manager_dns_ipv6_fd(m);
if (fd < 0)
return fd;
r = ioctl(fd, FIONREAD, &ms);
if (r < 0)
return -errno;
if (ms < 0)
return -EIO;
r = dns_packet_new(&p, ms);
if (r < 0)
return r;
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->allocated;
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
l = recvmsg(fd, &mh, 0);
if (l < 0) {
if (errno == EAGAIN)
return 0;
return -errno;
}
if (l <= 0)
return -EIO;
p->size = (size_t) l;
*ret = p;
p = NULL;
return 1;
}
static int on_dns_ipv4_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsQueryTransaction *t = NULL;
Manager *m = userdata;
int r;
r = manager_dns_ipv4_recv(m, &p);
if (r <= 0)
return r;
t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_HEADER(p)->id));
if (!t)
return 0;
return dns_query_transaction_reply(t, p);
}
static int on_dns_ipv6_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsQueryTransaction *t = NULL;
Manager *m = userdata;
int r;
r = manager_dns_ipv6_recv(m, &p);
if (r <= 0)
return r;
t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_HEADER(p)->id));
if (!t)
return 0;
return dns_query_transaction_reply(t, p);
}
int manager_dns_ipv4_fd(Manager *m) {
int r;
assert(m);
if (m->dns_ipv4_fd >= 0)
return m->dns_ipv4_fd;
m->dns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->dns_ipv4_fd < 0)
return -errno;
r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_ipv4_packet, m);
if (r < 0)
return r;
return m->dns_ipv4_fd;
}
int manager_dns_ipv6_fd(Manager *m) {
int r;
assert(m);
if (m->dns_ipv6_fd >= 0)
return m->dns_ipv6_fd;
m->dns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->dns_ipv6_fd < 0)
return -errno;
r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_ipv6_packet, m);
if (r < 0)
return r;
return m->dns_ipv6_fd;
}
static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
int r;
assert(fd >= 0);
assert(mh);
for (;;) {
if (sendmsg(fd, mh, flags) >= 0)
return 0;
if (errno == EINTR)
continue;
if (errno != EAGAIN)
return -errno;
r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
if (r < 0)
return r;
if (r == 0)
return -ETIMEDOUT;
}
}
int manager_dns_ipv4_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) {
union sockaddr_union sa = {
.in.sin_family = AF_INET,
.in.sin_port = htobe16(53),
};
struct msghdr mh = {};
struct iovec iov;
uint8_t control[CMSG_SPACE(sizeof(struct in_pktinfo))];
int fd;
assert(m);
assert(srv);
assert(p);
fd = manager_dns_ipv4_fd(m);
if (fd < 0)
return fd;
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->size;
sa.in.sin_addr = srv->address.in;
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_name = &sa.sa;
mh.msg_namelen = sizeof(sa.in);
if (ifindex > 0) {
struct cmsghdr *cmsg;
struct in_pktinfo *pi;
zero(control);
mh.msg_control = control;
mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_len = mh.msg_controllen;
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_PKTINFO;
pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
pi->ipi_ifindex = ifindex;
}
return sendmsg_loop(fd, &mh, 0);
}
int manager_dns_ipv6_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) {
union sockaddr_union sa = {
.in6.sin6_family = AF_INET6,
.in6.sin6_port = htobe16(53),
};
struct msghdr mh = {};
struct iovec iov;
uint8_t control[CMSG_SPACE(sizeof(struct in6_pktinfo))];
int fd;
assert(m);
assert(srv);
assert(p);
fd = manager_dns_ipv6_fd(m);
if (fd < 0)
return fd;
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->size;
sa.in6.sin6_addr = srv->address.in6;
sa.in6.sin6_scope_id = ifindex;
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_name = &sa.sa;
mh.msg_namelen = sizeof(sa.in6);
if (ifindex > 0) {
struct cmsghdr *cmsg;
struct in6_pktinfo *pi;
zero(control);
mh.msg_control = control;
mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo));
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_len = mh.msg_controllen;
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
pi->ipi6_ifindex = ifindex;
}
return sendmsg_loop(fd, &mh, 0);
}
DnsServer* manager_find_dns_server(Manager *m, unsigned char family, union in_addr_union *in_addr) {
DnsServer *s;
assert(m);
assert(in_addr);
LIST_FOREACH(servers, s, m->dns_servers) {
if (s->family == family &&
in_addr_equal(family, &s->address, in_addr))
return s;
}
return NULL;
}
DnsServer *manager_get_dns_server(Manager *m) {
assert(m);
if (!m->current_dns_server)
m->current_dns_server = m->dns_servers;
return m->current_dns_server;
}
void manager_next_dns_server(Manager *m) {
assert(m);
if (!m->current_dns_server) {
m->current_dns_server = m->dns_servers;
return;
}
if (!m->current_dns_server)
return;
if (m->current_dns_server->servers_next) {
m->current_dns_server = m->current_dns_server->servers_next;
return;
}
m->current_dns_server = m->dns_servers;
}
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