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synced 2024-11-01 17:51:22 +03:00
resolved: simplify error handling in manager_dns_stub_{udp,tcp}_fd()
Make sure an error is always printed… When systemd-resolved is started in a user namespace without private network, it would fail on setsockopt, but the error wouldn't be particularly informative: "Failed to start manager: permission denied."
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
parent
084f580557
commit
424e490b94
@ -25,6 +25,9 @@
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* IP and UDP header sizes */
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#define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U)
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static int manager_dns_stub_udp_fd(Manager *m);
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static int manager_dns_stub_tcp_fd(Manager *m);
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static int dns_stub_make_reply_packet(
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uint16_t id,
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int rcode,
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@ -354,66 +357,48 @@ static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void
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return 0;
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}
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int manager_dns_stub_udp_fd(Manager *m) {
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static int manager_dns_stub_udp_fd(Manager *m) {
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static const int one = 1;
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union sockaddr_union sa = {
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.in.sin_family = AF_INET,
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.in.sin_port = htobe16(53),
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.in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB),
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};
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_cleanup_close_ int fd = -1;
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int r;
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if (m->dns_stub_udp_fd >= 0)
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return m->dns_stub_udp_fd;
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m->dns_stub_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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if (m->dns_stub_udp_fd < 0)
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fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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if (fd < 0)
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return -errno;
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r = setsockopt(m->dns_stub_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one) < 0)
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return -errno;
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r = setsockopt(m->dns_stub_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof one) < 0)
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return -errno;
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r = setsockopt(m->dns_stub_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof one) < 0)
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return -errno;
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/* Make sure no traffic from outside the local host can leak to onto this socket */
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r = setsockopt(m->dns_stub_udp_fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3);
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3) < 0)
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return -errno;
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r = bind(m->dns_stub_udp_fd, &sa.sa, sizeof(sa.in));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (bind(fd, &sa.sa, sizeof(sa.in)) < 0)
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return -errno;
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r = sd_event_add_io(m->event, &m->dns_stub_udp_event_source, m->dns_stub_udp_fd, EPOLLIN, on_dns_stub_packet, m);
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r = sd_event_add_io(m->event, &m->dns_stub_udp_event_source, fd, EPOLLIN, on_dns_stub_packet, m);
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if (r < 0)
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goto fail;
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return r;
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(void) sd_event_source_set_description(m->dns_stub_udp_event_source, "dns-stub-udp");
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m->dns_stub_udp_fd = fd;
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fd = -1;
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return m->dns_stub_udp_fd;
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fail:
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m->dns_stub_udp_fd = safe_close(m->dns_stub_udp_fd);
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return r;
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}
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static int on_dns_stub_stream_packet(DnsStream *s) {
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@ -461,106 +446,77 @@ static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void
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return 0;
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}
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int manager_dns_stub_tcp_fd(Manager *m) {
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static int manager_dns_stub_tcp_fd(Manager *m) {
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static const int one = 1;
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union sockaddr_union sa = {
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.in.sin_family = AF_INET,
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.in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB),
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.in.sin_port = htobe16(53),
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};
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_cleanup_close_ int fd = -1;
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int r;
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if (m->dns_stub_tcp_fd >= 0)
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return m->dns_stub_tcp_fd;
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m->dns_stub_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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if (m->dns_stub_tcp_fd < 0)
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fd = socket(AF_INET, 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(m->dns_stub_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof one) < 0)
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return -errno;
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r = setsockopt(m->dns_stub_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one) < 0)
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return -errno;
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r = setsockopt(m->dns_stub_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof one) < 0)
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return -errno;
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r = setsockopt(m->dns_stub_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof one) < 0)
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return -errno;
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/* Make sure no traffic from outside the local host can leak to onto this socket */
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r = setsockopt(m->dns_stub_tcp_fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3);
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3) < 0)
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return -errno;
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r = bind(m->dns_stub_tcp_fd, &sa.sa, sizeof(sa.in));
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (bind(fd, &sa.sa, sizeof(sa.in)) < 0)
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return -errno;
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r = listen(m->dns_stub_tcp_fd, SOMAXCONN);
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if (r < 0) {
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r = -errno;
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goto fail;
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}
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if (listen(fd, SOMAXCONN) < 0)
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return -errno;
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r = sd_event_add_io(m->event, &m->dns_stub_tcp_event_source, m->dns_stub_tcp_fd, EPOLLIN, on_dns_stub_stream, m);
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r = sd_event_add_io(m->event, &m->dns_stub_tcp_event_source, fd, EPOLLIN, on_dns_stub_stream, m);
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if (r < 0)
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goto fail;
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return r;
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(void) sd_event_source_set_description(m->dns_stub_tcp_event_source, "dns-stub-tcp");
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m->dns_stub_tcp_fd = fd;
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fd = -1;
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return m->dns_stub_tcp_fd;
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fail:
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m->dns_stub_tcp_fd = safe_close(m->dns_stub_tcp_fd);
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return r;
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}
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int manager_dns_stub_start(Manager *m) {
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const char *t = "UDP";
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int r;
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assert(m);
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if (IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_UDP)) {
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if (IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_UDP))
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r = manager_dns_stub_udp_fd(m);
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if (r == -EADDRINUSE)
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goto eaddrinuse;
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if (r < 0)
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return r;
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}
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if (IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_TCP)) {
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if (r >= 0 &&
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IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_TCP)) {
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t = "TCP";
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r = manager_dns_stub_tcp_fd(m);
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if (r == -EADDRINUSE)
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goto eaddrinuse;
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if (r < 0)
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return r;
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}
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return 0;
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eaddrinuse:
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log_warning("Another process is already listening on 127.0.0.53:53. Turning off local DNS stub support.");
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if (r == -EADDRINUSE) {
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log_warning("Another process is already listening on %s socket 127.0.0.53:53.\n"
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"Turning off local DNS stub support.", t);
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manager_dns_stub_stop(m);
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} else if (r < 0)
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return log_error_errno(r, "Failed to listen on %s socket 127.0.0.53:53: %m", t);
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return 0;
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}
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@ -24,8 +24,5 @@
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/* 127.0.0.53 in native endian */
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#define INADDR_DNS_STUB ((in_addr_t) 0x7f000035U)
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int manager_dns_stub_udp_fd(Manager *m);
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int manager_dns_stub_tcp_fd(Manager *m);
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void manager_dns_stub_stop(Manager *m);
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int manager_dns_stub_start(Manager *m);
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