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-rw-r--r--src/nspawn/nspawn-expose-ports.c227
1 files changed, 227 insertions, 0 deletions
diff --git a/src/nspawn/nspawn-expose-ports.c b/src/nspawn/nspawn-expose-ports.c
new file mode 100644
index 0000000..13ce849
--- /dev/null
+++ b/src/nspawn/nspawn-expose-ports.c
@@ -0,0 +1,227 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "firewall-util.h"
+#include "in-addr-util.h"
+#include "local-addresses.h"
+#include "netlink-util.h"
+#include "nspawn-expose-ports.h"
+#include "parse-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "util.h"
+
+int expose_port_parse(ExposePort **l, const char *s) {
+
+ const char *split, *e;
+ uint16_t container_port, host_port;
+ int protocol;
+ ExposePort *p;
+ int r;
+
+ assert(l);
+ assert(s);
+
+ if ((e = startswith(s, "tcp:")))
+ protocol = IPPROTO_TCP;
+ else if ((e = startswith(s, "udp:")))
+ protocol = IPPROTO_UDP;
+ else {
+ e = s;
+ protocol = IPPROTO_TCP;
+ }
+
+ split = strchr(e, ':');
+ if (split) {
+ char v[split - e + 1];
+
+ memcpy(v, e, split - e);
+ v[split - e] = 0;
+
+ r = parse_ip_port(v, &host_port);
+ if (r < 0)
+ return -EINVAL;
+
+ r = parse_ip_port(split + 1, &container_port);
+ } else {
+ r = parse_ip_port(e, &container_port);
+ host_port = container_port;
+ }
+
+ if (r < 0)
+ return -EINVAL;
+
+ LIST_FOREACH(ports, p, *l)
+ if (p->protocol == protocol && p->host_port == host_port)
+ return -EEXIST;
+
+ p = new(ExposePort, 1);
+ if (!p)
+ return -ENOMEM;
+
+ p->protocol = protocol;
+ p->host_port = host_port;
+ p->container_port = container_port;
+
+ LIST_PREPEND(ports, *l, p);
+
+ return 0;
+}
+
+void expose_port_free_all(ExposePort *p) {
+
+ while (p) {
+ ExposePort *q = p;
+ LIST_REMOVE(ports, p, q);
+ free(q);
+ }
+}
+
+int expose_port_flush(ExposePort* l, union in_addr_union *exposed) {
+ ExposePort *p;
+ int r, af = AF_INET;
+
+ assert(exposed);
+
+ if (!l)
+ return 0;
+
+ if (in_addr_is_null(af, exposed))
+ return 0;
+
+ log_debug("Lost IP address.");
+
+ LIST_FOREACH(ports, p, l) {
+ r = fw_add_local_dnat(false,
+ af,
+ p->protocol,
+ NULL,
+ NULL, 0,
+ NULL, 0,
+ p->host_port,
+ exposed,
+ p->container_port,
+ NULL);
+ if (r < 0)
+ log_warning_errno(r, "Failed to modify firewall: %m");
+ }
+
+ *exposed = IN_ADDR_NULL;
+ return 0;
+}
+
+int expose_port_execute(sd_netlink *rtnl, ExposePort *l, union in_addr_union *exposed) {
+ _cleanup_free_ struct local_address *addresses = NULL;
+ _cleanup_free_ char *pretty = NULL;
+ union in_addr_union new_exposed;
+ ExposePort *p;
+ bool add;
+ int af = AF_INET, r;
+
+ assert(exposed);
+
+ /* Invoked each time an address is added or removed inside the
+ * container */
+
+ if (!l)
+ return 0;
+
+ r = local_addresses(rtnl, 0, af, &addresses);
+ if (r < 0)
+ return log_error_errno(r, "Failed to enumerate local addresses: %m");
+
+ add = r > 0 &&
+ addresses[0].family == af &&
+ addresses[0].scope < RT_SCOPE_LINK;
+
+ if (!add)
+ return expose_port_flush(l, exposed);
+
+ new_exposed = addresses[0].address;
+ if (in_addr_equal(af, exposed, &new_exposed))
+ return 0;
+
+ in_addr_to_string(af, &new_exposed, &pretty);
+ log_debug("New container IP is %s.", strna(pretty));
+
+ LIST_FOREACH(ports, p, l) {
+
+ r = fw_add_local_dnat(true,
+ af,
+ p->protocol,
+ NULL,
+ NULL, 0,
+ NULL, 0,
+ p->host_port,
+ &new_exposed,
+ p->container_port,
+ in_addr_is_null(af, exposed) ? NULL : exposed);
+ if (r < 0)
+ log_warning_errno(r, "Failed to modify firewall: %m");
+ }
+
+ *exposed = new_exposed;
+ return 0;
+}
+
+int expose_port_send_rtnl(int send_fd) {
+ _cleanup_close_ int fd = -1;
+ int r;
+
+ assert(send_fd >= 0);
+
+ fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_ROUTE);
+ if (fd < 0)
+ return log_error_errno(errno, "Failed to allocate container netlink: %m");
+
+ /* Store away the fd in the socket, so that it stays open as
+ * long as we run the child */
+ r = send_one_fd(send_fd, fd, 0);
+ if (r < 0)
+ return log_error_errno(r, "Failed to send netlink fd: %m");
+
+ return 0;
+}
+
+int expose_port_watch_rtnl(
+ sd_event *event,
+ int recv_fd,
+ sd_netlink_message_handler_t handler,
+ union in_addr_union *exposed,
+ sd_netlink **ret) {
+ _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+ int fd, r;
+
+ assert(event);
+ assert(recv_fd >= 0);
+ assert(ret);
+
+ fd = receive_one_fd(recv_fd, 0);
+ if (fd < 0)
+ return log_error_errno(fd, "Failed to recv netlink fd: %m");
+
+ r = sd_netlink_open_fd(&rtnl, fd);
+ if (r < 0) {
+ safe_close(fd);
+ return log_error_errno(r, "Failed to create rtnl object: %m");
+ }
+
+ r = sd_netlink_add_match(rtnl, NULL, RTM_NEWADDR, handler, NULL, exposed, "nspawn-NEWADDR");
+ if (r < 0)
+ return log_error_errno(r, "Failed to subscribe to RTM_NEWADDR messages: %m");
+
+ r = sd_netlink_add_match(rtnl, NULL, RTM_DELADDR, handler, NULL, exposed, "nspawn-DELADDR");
+ if (r < 0)
+ return log_error_errno(r, "Failed to subscribe to RTM_DELADDR messages: %m");
+
+ r = sd_netlink_attach_event(rtnl, event, 0);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add to even loop: %m");
+
+ *ret = TAKE_PTR(rtnl);
+
+ return 0;
+}