int manager_llmnr_ipv4_udp_fd(Manager *m) {
union sockaddr_union sa = {
.in.sin_family = AF_INET,
.in.sin_port = htobe16(LLMNR_PORT),
};
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(LLMNR_PORT),
};
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) {
DnsScope *scope;
assert(s);
scope = manager_find_scope(s->manager, s->read_packet);
if (!scope) {
log_warning("Got LLMNR TCP packet on unknown scope. Ignroing.");
return 0;
}
if (dns_packet_validate_query(s->read_packet) > 0) {
log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet));
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;
} else
log_debug("Invalid LLMNR TCP packet.");
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;
}
static int dns_transaction_open_tcp(DnsTransaction *t) {
DnsServer *server = NULL;
_cleanup_close_ int fd = -1;
int r;
assert(t);
if (t->stream)
return 0;
switch (t->scope->protocol) {
case DNS_PROTOCOL_DNS:
fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53, &server);
break;
case DNS_PROTOCOL_LLMNR:
/* When we already received a reply to this (but it was truncated), send to its sender address */
if (t->received)
fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port, NULL);
else {
union in_addr_union address;
int family = AF_UNSPEC;
/* Otherwise, try to talk to the owner of a
* the IP address, in case this is a reverse
* PTR lookup */
r = dns_name_address(DNS_RESOURCE_KEY_NAME(t->key), &family, &address);
if (r < 0)
return r;
if (r == 0)
return -EINVAL;
if (family != t->scope->family)
return -ESRCH;
fd = dns_scope_tcp_socket(t->scope, family, &address, LLMNR_PORT, NULL);
}
break;
default:
return -EAFNOSUPPORT;
}
if (fd < 0)
return fd;
r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd);
if (r < 0)
return r;
fd = -1;
r = dns_stream_write_packet(t->stream, t->sent);
if (r < 0) {
t->stream = dns_stream_free(t->stream);
return r;
}
dns_server_unref(t->server);
t->server = dns_server_ref(server);
t->received = dns_packet_unref(t->received);
t->stream->complete = on_stream_complete;
t->stream->transaction = t;
/* The interface index is difficult to determine if we are
* connecting to the local host, hence fill this in right away
* instead of determining it from the socket */
if (t->scope->link)
t->stream->ifindex = t->scope->link->ifindex;
return 0;
}
