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-rw-r--r--src/nspawn/nspawn-expose-ports.c277
1 files changed, 277 insertions, 0 deletions
diff --git a/src/nspawn/nspawn-expose-ports.c b/src/nspawn/nspawn-expose-ports.c
new file mode 100644
index 0000000000..38250b6e02
--- /dev/null
+++ b/src/nspawn/nspawn-expose-ports.c
@@ -0,0 +1,277 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2015 Lennart Poettering
+
+ 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 "sd-netlink.h"
+
+#include "util.h"
+#include "in-addr-util.h"
+#include "firewall-util.h"
+#include "local-addresses.h"
+#include "netlink-util.h"
+
+#include "nspawn-expose-ports.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 = safe_atou16(v, &host_port);
+ if (r < 0 || host_port <= 0)
+ return -EINVAL;
+
+ r = safe_atou16(split + 1, &container_port);
+ } else {
+ r = safe_atou16(e, &container_port);
+ host_port = container_port;
+ }
+
+ if (r < 0 || container_port <= 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) {
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int))];
+ } control = {};
+ struct msghdr mh = {
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ struct cmsghdr *cmsg;
+ _cleanup_close_ int fd = -1;
+ ssize_t k;
+
+ 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");
+
+ cmsg = CMSG_FIRSTHDR(&mh);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
+
+ mh.msg_controllen = cmsg->cmsg_len;
+
+ /* Store away the fd in the socket, so that it stays open as
+ * long as we run the child */
+ k = sendmsg(send_fd, &mh, MSG_NOSIGNAL);
+ if (k < 0)
+ return log_error_errno(errno, "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) {
+
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int))];
+ } control = {};
+ struct msghdr mh = {
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ struct cmsghdr *cmsg;
+ _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+ int fd, r;
+ ssize_t k;
+
+ assert(event);
+ assert(recv_fd >= 0);
+ assert(ret);
+
+ k = recvmsg(recv_fd, &mh, MSG_NOSIGNAL);
+ if (k < 0)
+ return log_error_errno(errno, "Failed to recv netlink fd: %m");
+
+ cmsg = CMSG_FIRSTHDR(&mh);
+ assert(cmsg->cmsg_level == SOL_SOCKET);
+ assert(cmsg->cmsg_type == SCM_RIGHTS);
+ assert(cmsg->cmsg_len == CMSG_LEN(sizeof(int)));
+ memcpy(&fd, CMSG_DATA(cmsg), sizeof(int));
+
+ 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, RTM_NEWADDR, handler, exposed);
+ if (r < 0)
+ return log_error_errno(r, "Failed to subscribe to RTM_NEWADDR messages: %m");
+
+ r = sd_netlink_add_match(rtnl, RTM_DELADDR, handler, exposed);
+ 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 = rtnl;
+ rtnl = NULL;
+
+ return 0;
+}
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