553 lines
18 KiB
C
553 lines
18 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <netinet/tcp.h>
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#include "missing.h"
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#include "strv.h"
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#include "socket-util.h"
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#include "af-list.h"
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#include "resolved-dns-domain.h"
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#include "resolved-dns-scope.h"
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int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) {
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DnsScope *s;
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assert(m);
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assert(ret);
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s = new0(DnsScope, 1);
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if (!s)
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return -ENOMEM;
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s->manager = m;
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s->link = l;
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s->protocol = protocol;
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s->family = family;
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LIST_PREPEND(scopes, m->dns_scopes, s);
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dns_scope_llmnr_membership(s, true);
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log_debug("New scope on link %s, protocol %s, family %s", l ? l->name : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family));
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*ret = s;
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return 0;
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}
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DnsScope* dns_scope_free(DnsScope *s) {
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DnsTransaction *t;
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if (!s)
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return NULL;
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log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->name : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family));
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dns_scope_llmnr_membership(s, false);
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while ((t = s->transactions)) {
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/* Abort the transaction, but make sure it is not
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* freed while we still look at it */
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t->block_gc++;
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dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
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t->block_gc--;
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dns_transaction_free(t);
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}
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dns_cache_flush(&s->cache);
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dns_zone_flush(&s->zone);
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LIST_REMOVE(scopes, s->manager->dns_scopes, s);
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strv_free(s->domains);
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free(s);
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return NULL;
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}
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DnsServer *dns_scope_get_dns_server(DnsScope *s) {
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assert(s);
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if (s->protocol != DNS_PROTOCOL_DNS)
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return NULL;
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if (s->link)
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return link_get_dns_server(s->link);
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else
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return manager_get_dns_server(s->manager);
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}
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void dns_scope_next_dns_server(DnsScope *s) {
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assert(s);
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if (s->protocol != DNS_PROTOCOL_DNS)
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return;
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if (s->link)
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link_next_dns_server(s->link);
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else
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manager_next_dns_server(s->manager);
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}
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int dns_scope_send(DnsScope *s, DnsPacket *p) {
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union in_addr_union addr;
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int ifindex = 0, r;
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int family;
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uint16_t port;
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uint32_t mtu;
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int fd;
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assert(s);
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assert(p);
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assert(p->protocol == s->protocol);
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if (s->link) {
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mtu = s->link->mtu;
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ifindex = s->link->ifindex;
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} else
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mtu = manager_find_mtu(s->manager);
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if (s->protocol == DNS_PROTOCOL_DNS) {
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DnsServer *srv;
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if (DNS_PACKET_QDCOUNT(p) > 1)
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return -ENOTSUP;
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srv = dns_scope_get_dns_server(s);
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if (!srv)
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return -ESRCH;
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family = srv->family;
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addr = srv->address;
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port = 53;
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if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
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return -EMSGSIZE;
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if (p->size > mtu)
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return -EMSGSIZE;
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if (family == AF_INET)
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fd = manager_dns_ipv4_fd(s->manager);
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else if (family == AF_INET6)
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fd = manager_dns_ipv6_fd(s->manager);
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else
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return -EAFNOSUPPORT;
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if (fd < 0)
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return fd;
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} else if (s->protocol == DNS_PROTOCOL_LLMNR) {
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if (DNS_PACKET_QDCOUNT(p) > 1)
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return -ENOTSUP;
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family = s->family;
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port = 5355;
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if (family == AF_INET) {
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addr.in = LLMNR_MULTICAST_IPV4_ADDRESS;
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fd = manager_llmnr_ipv4_udp_fd(s->manager);
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} else if (family == AF_INET6) {
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addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS;
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fd = manager_llmnr_ipv6_udp_fd(s->manager);
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} else
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return -EAFNOSUPPORT;
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if (fd < 0)
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return fd;
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} else
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return -EAFNOSUPPORT;
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r = manager_send(s->manager, fd, ifindex, family, &addr, port, p);
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if (r < 0)
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return r;
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return 1;
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}
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int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port) {
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_cleanup_close_ int fd = -1;
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union sockaddr_union sa = {};
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socklen_t salen;
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static const int one = 1;
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int ret, r;
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assert(s);
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assert((family == AF_UNSPEC) == !address);
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if (family == AF_UNSPEC) {
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DnsServer *srv;
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srv = dns_scope_get_dns_server(s);
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if (!srv)
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return -ESRCH;
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sa.sa.sa_family = srv->family;
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if (srv->family == AF_INET) {
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sa.in.sin_port = htobe16(port);
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sa.in.sin_addr = srv->address.in;
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salen = sizeof(sa.in);
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} else if (srv->family == AF_INET6) {
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sa.in6.sin6_port = htobe16(port);
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sa.in6.sin6_addr = srv->address.in6;
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sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
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salen = sizeof(sa.in6);
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} else
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return -EAFNOSUPPORT;
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} else {
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sa.sa.sa_family = family;
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if (family == AF_INET) {
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sa.in.sin_port = htobe16(port);
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sa.in.sin_addr = address->in;
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salen = sizeof(sa.in);
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} else if (family == AF_INET6) {
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sa.in6.sin6_port = htobe16(port);
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sa.in6.sin6_addr = address->in6;
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sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
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salen = sizeof(sa.in6);
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} else
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return -EAFNOSUPPORT;
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}
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fd = socket(sa.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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if (fd < 0)
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return -errno;
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r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
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if (r < 0)
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return -errno;
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if (s->link) {
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uint32_t ifindex = htobe32(s->link->ifindex);
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if (sa.sa.sa_family == AF_INET) {
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r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex));
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if (r < 0)
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return -errno;
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} else if (sa.sa.sa_family == AF_INET6) {
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r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex));
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if (r < 0)
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return -errno;
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}
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}
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if (s->protocol == DNS_PROTOCOL_LLMNR) {
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/* RFC 4795, section 2.5 requires the TTL to be set to 1 */
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if (sa.sa.sa_family == AF_INET) {
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r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
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if (r < 0)
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return -errno;
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} else if (sa.sa.sa_family == AF_INET6) {
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r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
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if (r < 0)
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return -errno;
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}
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}
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r = connect(fd, &sa.sa, salen);
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if (r < 0 && errno != EINPROGRESS)
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return -errno;
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ret = fd;
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fd = -1;
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return ret;
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}
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DnsScopeMatch dns_scope_good_domain(DnsScope *s, const char *domain) {
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char **i;
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assert(s);
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assert(domain);
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STRV_FOREACH(i, s->domains)
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if (dns_name_endswith(domain, *i) > 0)
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return DNS_SCOPE_YES;
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if (dns_name_root(domain) != 0)
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return DNS_SCOPE_NO;
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if (is_localhost(domain))
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return DNS_SCOPE_NO;
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if (s->protocol == DNS_PROTOCOL_DNS) {
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if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
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dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0 &&
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dns_name_single_label(domain) == 0)
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return DNS_SCOPE_MAYBE;
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return DNS_SCOPE_NO;
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}
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if (s->protocol == DNS_PROTOCOL_MDNS) {
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if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0 ||
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dns_name_endswith(domain, "0.8.e.f.ip6.arpa") > 0 ||
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(dns_name_endswith(domain, "local") > 0 && dns_name_equal(domain, "local") == 0))
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return DNS_SCOPE_MAYBE;
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return DNS_SCOPE_NO;
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}
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if (s->protocol == DNS_PROTOCOL_LLMNR) {
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if (dns_name_endswith(domain, "in-addr.arpa") > 0 ||
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dns_name_endswith(domain, "ip6.arpa") > 0 ||
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dns_name_single_label(domain) > 0)
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return DNS_SCOPE_MAYBE;
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return DNS_SCOPE_NO;
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}
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assert_not_reached("Unknown scope protocol");
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}
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int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) {
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assert(s);
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assert(key);
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if (s->protocol == DNS_PROTOCOL_DNS)
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return true;
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/* On mDNS and LLMNR, send A and AAAA queries only on the
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* respective scopes */
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if (s->family == AF_INET && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_AAAA)
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return false;
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if (s->family == AF_INET6 && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_A)
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return false;
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return true;
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}
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int dns_scope_llmnr_membership(DnsScope *s, bool b) {
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int fd;
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if (s->family == AF_INET) {
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struct ip_mreqn mreqn = {
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.imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS,
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.imr_ifindex = s->link->ifindex,
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};
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fd = manager_llmnr_ipv4_udp_fd(s->manager);
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if (fd < 0)
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return fd;
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if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0)
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return -errno;
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} else if (s->family == AF_INET6) {
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struct ipv6_mreq mreq = {
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.ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS,
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.ipv6mr_interface = s->link->ifindex,
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};
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fd = manager_llmnr_ipv6_udp_fd(s->manager);
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if (fd < 0)
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return fd;
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if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
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return -errno;
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} else
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return -EAFNOSUPPORT;
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return 0;
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}
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int dns_scope_good_dns_server(DnsScope *s, int family, const union in_addr_union *address) {
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assert(s);
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assert(address);
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if (s->protocol != DNS_PROTOCOL_DNS)
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return 1;
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if (s->link)
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return !!link_find_dns_server(s->link, family, address);
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else
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return !!manager_find_dns_server(s->manager, family, address);
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}
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static int dns_scope_make_reply_packet(
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DnsScope *s,
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uint16_t id,
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int rcode,
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DnsQuestion *q,
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DnsAnswer *answer,
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DnsAnswer *soa,
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bool tentative,
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DnsPacket **ret) {
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_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
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unsigned i;
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int r;
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assert(s);
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if (q->n_keys <= 0 && answer->n_rrs <= 0 && soa->n_rrs <= 0)
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return -EINVAL;
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r = dns_packet_new(&p, s->protocol, 0);
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if (r < 0)
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return r;
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DNS_PACKET_HEADER(p)->id = id;
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DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
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1 /* qr */,
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0 /* opcode */,
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0 /* c */,
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0 /* tc */,
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tentative,
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0 /* (ra) */,
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0 /* (ad) */,
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0 /* (cd) */,
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rcode));
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if (q) {
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for (i = 0; i < q->n_keys; i++) {
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r = dns_packet_append_key(p, q->keys[i], NULL);
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if (r < 0)
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return r;
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}
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DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys);
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}
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if (answer) {
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for (i = 0; i < answer->n_rrs; i++) {
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r = dns_packet_append_rr(p, answer->rrs[i], NULL);
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if (r < 0)
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return r;
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}
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DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs);
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}
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if (soa) {
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for (i = 0; i < soa->n_rrs; i++) {
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r = dns_packet_append_rr(p, soa->rrs[i], NULL);
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if (r < 0)
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return r;
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}
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DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs);
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}
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*ret = p;
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p = NULL;
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return 0;
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}
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void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
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_cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
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_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
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bool tentative = false;
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int r, fd;
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assert(s);
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assert(p);
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if (p->protocol != DNS_PROTOCOL_LLMNR)
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return;
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if (p->ipproto == IPPROTO_UDP) {
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/* Don't accept UDP queries directed to anything but
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* the LLMNR multicast addresses. See RFC 4795,
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* section 2.5.*/
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if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
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return;
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if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
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return;
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}
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r = dns_packet_extract(p);
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if (r < 0) {
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log_debug("Failed to extract resources from incoming packet: %s", strerror(-r));
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return;
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}
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if (DNS_PACKET_C(p)) {
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/* FIXME: Somebody notified us about a likely conflict */
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return;
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}
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r = dns_zone_lookup(&s->zone, p->question, &answer, &soa, &tentative);
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if (r < 0) {
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log_debug("Failed to lookup key: %s", strerror(-r));
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return;
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}
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if (r == 0)
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return;
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if (answer)
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dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0);
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r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply);
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if (r < 0) {
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log_debug("Failed to build reply packet: %s", strerror(-r));
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return;
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}
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if (stream)
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r = dns_stream_write_packet(stream, reply);
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else {
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if (p->family == AF_INET)
|
|
fd = manager_llmnr_ipv4_udp_fd(s->manager);
|
|
else if (p->family == AF_INET6)
|
|
fd = manager_llmnr_ipv6_udp_fd(s->manager);
|
|
else {
|
|
log_debug("Unknown protocol");
|
|
return;
|
|
}
|
|
if (fd < 0) {
|
|
log_debug("Failed to get reply socket: %s", strerror(-fd));
|
|
return;
|
|
}
|
|
|
|
r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply);
|
|
}
|
|
|
|
if (r < 0) {
|
|
log_debug("Failed to send reply packet: %s", strerror(-r));
|
|
return;
|
|
}
|
|
}
|
|
|
|
DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsQuestion *question) {
|
|
DnsTransaction *t;
|
|
|
|
assert(scope);
|
|
assert(question);
|
|
|
|
/* Try to find an ongoing transaction that is a equal or a
|
|
* superset of the specified question */
|
|
|
|
LIST_FOREACH(transactions_by_scope, t, scope->transactions)
|
|
if (dns_question_is_superset(t->question, question) > 0)
|
|
return t;
|
|
|
|
return NULL;
|
|
}
|