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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 <net/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 "network-internal.h"
#include "conf-parser.h"
#include "socket-util.h"
#include "af-list.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:{
bool is_new = !l;
if (!l) {
r = link_new(m, &l, ifindex);
if (r < 0)
goto fail;
}
r = link_update_rtnl(l, mm);
if (r < 0)
goto fail;
if (is_new)
log_debug("Found new link %i/%s", ifindex, l->name);
break;
}
case RTM_DELLINK:
if (l) {
log_debug("Removing link %i/%s", l->ifindex, l->name);
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;
uint16_t type;
int r, ifindex, family;
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(&m->network_monitor, NULL);
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) {
const char *word, *state;
size_t length;
int r;
assert(m);
assert(string);
FOREACH_WORD_QUOTED(word, length, string, state) {
char buffer[length+1];
int 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, NULL, family, &addr);
if (r < 0)
return r;
}
/* do not warn about state here, since probably systemd already did */
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) {
assert(m);
return config_parse(NULL, "/etc/systemd/resolved.conf", NULL,
"Resolve\0",
config_item_perf_lookup, resolved_gperf_lookup,
false, false, true, m);
}
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;
m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1;
m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1;
m->use_llmnr = true;
r = parse_dns_server_string(m, DNS_SERVERS);
if (r < 0)
return r;
m->hostname = gethostname_malloc();
if (!m->hostname)
return -ENOMEM;
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, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
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;
r = manager_llmnr_ipv4_udp_fd(m);
if (r < 0)
return r;
r = manager_llmnr_ipv6_udp_fd(m);
if (r < 0)
return r;
r = manager_llmnr_ipv4_tcp_fd(m);
if (r < 0)
return r;
r = manager_llmnr_ipv6_tcp_fd(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_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->llmnr_ipv4_udp_event_source);
sd_event_source_unref(m->llmnr_ipv6_udp_event_source);
safe_close(m->llmnr_ipv4_udp_fd);
safe_close(m->llmnr_ipv6_udp_fd);
sd_event_source_unref(m->llmnr_ipv4_tcp_event_source);
sd_event_source_unref(m->llmnr_ipv6_tcp_event_source);
safe_close(m->llmnr_ipv4_tcp_fd);
safe_close(m->llmnr_ipv6_tcp_fd);
sd_event_source_unref(m->bus_retry_event_source);
sd_bus_unref(m->bus);
sd_event_unref(m->event);
dns_resource_key_unref(m->host_ipv4_key);
dns_resource_key_unref(m->host_ipv6_key);
free(m->hostname);
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->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_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
union {
struct cmsghdr header; /* For alignment */
uint8_t buffer[CMSG_SPACE(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+ CMSG_SPACE(int) /* ttl/hoplimit */
+ EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */];
} control;
union sockaddr_union sa;
struct msghdr mh = {};
struct cmsghdr *cmsg;
struct iovec iov;
int ms = 0, r;
ssize_t l;
assert(m);
assert(fd >= 0);
assert(ret);
r = ioctl(fd, FIONREAD, &ms);
if (r < 0)
return -errno;
if (ms < 0)
return -EIO;
r = dns_packet_new(&p, protocol, ms);
if (r < 0)
return r;
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->allocated;
mh.msg_name = &sa.sa;
mh.msg_namelen = sizeof(sa);
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
l = recvmsg(fd, &mh, 0);
if (l < 0) {
if (errno == EAGAIN || errno == EINTR)
return 0;
return -errno;
}
if (l <= 0)
return -EIO;
assert(!(mh.msg_flags & MSG_CTRUNC));
assert(!(mh.msg_flags & MSG_TRUNC));
p->size = (size_t) l;
p->family = sa.sa.sa_family;
p->ipproto = IPPROTO_UDP;
if (p->family == AF_INET) {
p->sender.in = sa.in.sin_addr;
p->sender_port = be16toh(sa.in.sin_port);
} else if (p->family == AF_INET6) {
p->sender.in6 = sa.in6.sin6_addr;
p->sender_port = be16toh(sa.in6.sin6_port);
p->ifindex = sa.in6.sin6_scope_id;
} else
return -EAFNOSUPPORT;
for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IPV6) {
assert(p->family == AF_INET6);
switch (cmsg->cmsg_type) {
case IPV6_PKTINFO: {
struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
if (p->ifindex <= 0)
p->ifindex = i->ipi6_ifindex;
p->destination.in6 = i->ipi6_addr;
break;
}
case IPV6_HOPLIMIT:
p->ttl = *(int *) CMSG_DATA(cmsg);
break;
}
} else if (cmsg->cmsg_level == IPPROTO_IP) {
assert(p->family == AF_INET);
switch (cmsg->cmsg_type) {
case IP_PKTINFO: {
struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
if (p->ifindex <= 0)
p->ifindex = i->ipi_ifindex;
p->destination.in = i->ipi_addr;
break;
}
case IP_TTL:
p->ttl = *(int *) CMSG_DATA(cmsg);
break;
}
}
}
/* The Linux kernel sets the interface index to the loopback
* device if the packet came from the local host since it
* avoids the routing table in such a case. Let's unset the
* interface index in such a case. */
if (p->ifindex > 0 && manager_ifindex_is_loopback(m, p->ifindex) != 0)
p->ifindex = 0;
/* If we don't know the interface index still, we look for the
* first local interface with a matching address. Yuck! */
if (p->ifindex <= 0)
p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
*ret = p;
p = NULL;
return 1;
}
static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsTransaction *t = NULL;
Manager *m = userdata;
int r;
r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p);
if (r <= 0)
return r;
if (dns_packet_validate_reply(p) > 0) {
t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
if (!t)
return 0;
dns_transaction_process_reply(t, p);
} else
log_debug("Invalid DNS packet.");
return 0;
}
int manager_dns_ipv4_fd(Manager *m) {
const int one = 1;
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 = setsockopt(m->dns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_packet, m);
if (r < 0)
goto fail;
return m->dns_ipv4_fd;
fail:
m->dns_ipv4_fd = safe_close(m->dns_ipv4_fd);
return r;
}
int manager_dns_ipv6_fd(Manager *m) {
const int one = 1;
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 = setsockopt(m->dns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_packet, m);
if (r < 0)
goto fail;
return m->dns_ipv6_fd;
fail:
m->dns_ipv6_fd = safe_close(m->dns_ipv6_fd);
return r;
}
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;
}
}
static int manager_ipv4_send(Manager *m, int fd, int ifindex, const struct in_addr *addr, uint16_t port, DnsPacket *p) {
union sockaddr_union sa = {
.in.sin_family = AF_INET,
};
union {
struct cmsghdr header; /* For alignment */
uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))];
} control;
struct msghdr mh = {};
struct iovec iov;
assert(m);
assert(fd >= 0);
assert(addr);
assert(port > 0);
assert(p);
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->size;
sa.in.sin_addr = *addr;
sa.in.sin_port = htobe16(port),
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);
}
static int manager_ipv6_send(Manager *m, int fd, int ifindex, const struct in6_addr *addr, uint16_t port, DnsPacket *p) {
union sockaddr_union sa = {
.in6.sin6_family = AF_INET6,
};
union {
struct cmsghdr header; /* For alignment */
uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))];
} control;
struct msghdr mh = {};
struct iovec iov;
assert(m);
assert(fd >= 0);
assert(addr);
assert(port > 0);
assert(p);
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->size;
sa.in6.sin6_addr = *addr;
sa.in6.sin6_port = htobe16(port),
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);
}
int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *addr, uint16_t port, DnsPacket *p) {
assert(m);
assert(fd >= 0);
assert(addr);
assert(port > 0);
assert(p);
log_debug("Sending %s packet with id %u on interface %i/%s", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family));
if (family == AF_INET)
return manager_ipv4_send(m, fd, ifindex, &addr->in, port, p);
else if (family == AF_INET6)
return manager_ipv6_send(m, fd, ifindex, &addr->in6, port, p);
return -EAFNOSUPPORT;
}
DnsServer* manager_find_dns_server(Manager *m, int family, const 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;
}
uint32_t manager_find_mtu(Manager *m) {
uint32_t mtu = 0;
Link *l;
Iterator i;
/* If we don't know on which link a DNS packet would be
* delivered, let's find the largest MTU that works on all
* interfaces we know of */
HASHMAP_FOREACH(l, m->links, i) {
if (l->mtu <= 0)
continue;
if (mtu <= 0 || l->mtu < mtu)
mtu = l->mtu;
}
return mtu;
}
static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsTransaction *t = NULL;
Manager *m = userdata;
int r;
r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p);
if (r <= 0)
return r;
if (dns_packet_validate_reply(p) > 0) {
log_debug("Got reply packet for id %u", DNS_PACKET_ID(p));
t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
if (!t)
return 0;
dns_transaction_process_reply(t, p);
} else if (dns_packet_validate_query(p) > 0) {
Link *l;
l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
if (l) {
DnsScope *scope = NULL;
if (p->family == AF_INET)
scope = l->llmnr_ipv4_scope;
else if (p->family == AF_INET6)
scope = l->llmnr_ipv6_scope;
if (scope)
dns_scope_process_query(scope, NULL, p);
}
} else
log_debug("Invalid LLMNR packet.");
return 0;
}
int manager_llmnr_ipv4_udp_fd(Manager *m) {
union sockaddr_union sa = {
.in.sin_family = AF_INET,
.in.sin_port = htobe16(5355),
};
static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255;
int r;
assert(m);
if (m->llmnr_ipv4_udp_fd >= 0)
return m->llmnr_ipv4_udp_fd;
m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->llmnr_ipv4_udp_fd < 0)
return -errno;
/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
/* Disable Don't-Fragment bit in the IP header */
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
if (r < 0) {
r = -errno;
goto fail;
}
r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in));
if (r < 0) {
r = -errno;
goto fail;
}
r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m);
if (r < 0)
goto fail;
return m->llmnr_ipv4_udp_fd;
fail:
m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd);
return r;
}
int manager_llmnr_ipv6_udp_fd(Manager *m) {
union sockaddr_union sa = {
.in6.sin6_family = AF_INET6,
.in6.sin6_port = htobe16(5355),
};
static const int one = 1, ttl = 255;
int r;
assert(m);
if (m->llmnr_ipv6_udp_fd >= 0)
return m->llmnr_ipv6_udp_fd;
m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->llmnr_ipv6_udp_fd < 0)
return -errno;
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
}
/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6));
if (r < 0) {
r = -errno;
goto fail;
}
r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m);
if (r < 0) {
r = -errno;
goto fail;
}
return m->llmnr_ipv6_udp_fd;
fail:
m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd);
return r;
}
static int on_llmnr_stream_packet(DnsStream *s) {
assert(s);
if (dns_packet_validate_query(s->read_packet) > 0) {
Link *l;
l = hashmap_get(s->manager->links, INT_TO_PTR(s->read_packet->ifindex));
if (l) {
DnsScope *scope = NULL;
if (s->read_packet->family == AF_INET)
scope = l->llmnr_ipv4_scope;
else if (s->read_packet->family == AF_INET6)
scope = l->llmnr_ipv6_scope;
if (scope) {
dns_scope_process_query(scope, s, s->read_packet);
/* If no reply packet was set, we free the stream */
if (s->write_packet)
return 0;
}
}
}
dns_stream_free(s);
return 0;
}
static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
DnsStream *stream;
Manager *m = userdata;
int cfd, r;
cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
if (cfd < 0) {
if (errno == EAGAIN || errno == EINTR)
return 0;
return -errno;
}
r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd);
if (r < 0) {
safe_close(cfd);
return r;
}
stream->on_packet = on_llmnr_stream_packet;
return 0;
}
int manager_llmnr_ipv4_tcp_fd(Manager *m) {
union sockaddr_union sa = {
.in.sin_family = AF_INET,
.in.sin_port = htobe16(5355),
};
static const int one = 1, pmtu = IP_PMTUDISC_DONT;
int r;
assert(m);
if (m->llmnr_ipv4_tcp_fd >= 0)
return m->llmnr_ipv4_tcp_fd;
m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->llmnr_ipv4_tcp_fd < 0)
return -errno;
/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
/* Disable Don't-Fragment bit in the IP header */
r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu));
if (r < 0) {
r = -errno;
goto fail;
}
r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in));
if (r < 0) {
r = -errno;
goto fail;
}
r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN);
if (r < 0) {
r = -errno;
goto fail;
}
r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m);
if (r < 0)
goto fail;
return m->llmnr_ipv4_tcp_fd;
fail:
m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd);
return r;
}
int manager_llmnr_ipv6_tcp_fd(Manager *m) {
union sockaddr_union sa = {
.in6.sin6_family = AF_INET6,
.in6.sin6_port = htobe16(5355),
};
static const int one = 1;
int r;
assert(m);
if (m->llmnr_ipv6_tcp_fd >= 0)
return m->llmnr_ipv6_tcp_fd;
m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (m->llmnr_ipv6_tcp_fd < 0)
return -errno;
/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one));
if (r < 0) {
r = -errno;
goto fail;
}
r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6));
if (r < 0) {
r = -errno;
goto fail;
}
r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN);
if (r < 0) {
r = -errno;
goto fail;
}
r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m);
if (r < 0) {
r = -errno;
goto fail;
}
return m->llmnr_ipv6_tcp_fd;
fail:
m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd);
return r;
}
int manager_ifindex_is_loopback(Manager *m, int ifindex) {
Link *l;
assert(m);
if (ifindex <= 0)
return -EINVAL;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (l->flags & IFF_LOOPBACK)
return 1;
return 0;
}
int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
LinkAddress *a;
assert(m);
a = manager_find_address(m, family, in_addr);
if (a)
return a->link->ifindex;
return 0;
}
int manager_next_hostname(Manager *m) {
const char *p;
Iterator i;
uint64_t u;
char *h;
Link *l;
assert(m);
p = strchr(m->hostname, 0);
assert(p);
while (p > m->hostname) {
if (!strchr("0123456789", p[-1]))
break;
p--;
}
if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
u = 1;
u++;
if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->hostname), m->hostname, u) < 0)
return -ENOMEM;
log_info("Hostname conflict, changing local hostname from '%s' to '%s'.", m->hostname, h);
free(m->hostname);
m->hostname = h;
m->host_ipv4_key = dns_resource_key_unref(m->host_ipv4_key);
m->host_ipv6_key = dns_resource_key_unref(m->host_ipv6_key);
HASHMAP_FOREACH(l, m->links, i) {
link_add_rrs(l, true);
link_add_rrs(l, false);
}
return 0;
}
LinkAddress* manager_find_address(Manager *m, int family, const union in_addr_union *in_addr) {
Iterator i;
Link *l;
assert(m);
HASHMAP_FOREACH(l, m->links, i) {
LinkAddress *a;
a = link_find_address(l, family, in_addr);
if (a)
return a;
}
return NULL;
}
int manager_our_packet(Manager *m, DnsPacket *p) {
assert(m);
assert(p);
return !!manager_find_address(m, p->family, &p->sender);
}
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