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nspawn: Move --network-interface interfaces back to the host.

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This commit is contained in:
Daan De Meyer 2019-12-19 21:17:57 +01:00 committed by Daan De Meyer
parent b390f17892
commit 5b4855ab73
3 changed files with 48 additions and 10 deletions
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6
src/nspawn/nspawn-network.c
View File

@ -438,7 +438,7 @@ int test_network_interface_initialized(const char *name) {
return 0;
}
int move_network_interfaces(pid_t pid, char **ifaces) {
int move_network_interfaces(int netns_fd, char **ifaces) {
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
char **i;
int r;
@ -462,9 +462,9 @@ int move_network_interfaces(pid_t pid, char **ifaces) {
if (r < 0)
return log_error_errno(r, "Failed to allocate netlink message: %m");
r = sd_netlink_message_append_u32(m, IFLA_NET_NS_PID, pid);
r = sd_netlink_message_append_u32(m, IFLA_NET_NS_FD, netns_fd);
if (r < 0)
return log_error_errno(r, "Failed to append namespace PID to netlink message: %m");
return log_error_errno(r, "Failed to append namespace fd to netlink message: %m");
r = sd_netlink_call(rtnl, m, 0, NULL);
if (r < 0)

2
src/nspawn/nspawn-network.h
View File

@ -16,7 +16,7 @@ int remove_bridge(const char *bridge_name);
int setup_macvlan(const char *machine_name, pid_t pid, char **ifaces);
int setup_ipvlan(const char *machine_name, pid_t pid, char **ifaces);
int move_network_interfaces(pid_t pid, char **ifaces);
int move_network_interfaces(int netns_fd, char **ifaces);
int veth_extra_parse(char ***l, const char *p);

50
src/nspawn/nspawn.c
View File

@ -4211,7 +4211,7 @@ static int run_container(
int ifi = 0, r;
ssize_t l;
sigset_t mask_chld;
_cleanup_close_ int netns_fd = -1;
_cleanup_close_ int child_netns_fd = -1;
assert_se(sigemptyset(&mask_chld) == 0);
assert_se(sigaddset(&mask_chld, SIGCHLD) == 0);
@ -4270,11 +4270,11 @@ static int run_container(
return log_error_errno(errno, "Failed to install SIGCHLD handler: %m");
if (arg_network_namespace_path) {
netns_fd = open(arg_network_namespace_path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (netns_fd < 0)
child_netns_fd = open(arg_network_namespace_path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (child_netns_fd < 0)
return log_error_errno(errno, "Cannot open file %s: %m", arg_network_namespace_path);
r = fd_is_network_ns(netns_fd);
r = fd_is_network_ns(child_netns_fd);
if (r == -EUCLEAN)
log_debug_errno(r, "Cannot determine if passed network namespace path '%s' really refers to a network namespace, assuming it does.", arg_network_namespace_path);
else if (r < 0)
@ -4319,7 +4319,7 @@ static int run_container(
master_pty_socket_pair[1],
unified_cgroup_hierarchy_socket_pair[1],
fds,
netns_fd);
child_netns_fd);
if (r < 0)
_exit(EXIT_FAILURE);
@ -4421,7 +4421,15 @@ static int run_container(
return log_error_errno(SYNTHETIC_ERRNO(ESRCH), "Child died too early");
}
r = move_network_interfaces(*pid, arg_network_interfaces);
if (child_netns_fd < 0) {
/* Make sure we have an open file descriptor to the child's network
* namespace so it stays alive even if the child exits. */
r = namespace_open(*pid, NULL, NULL, &child_netns_fd, NULL, NULL);
if (r < 0)
return log_error_errno(r, "Failed to open child network namespace: %m");
}
r = move_network_interfaces(child_netns_fd, arg_network_interfaces);
if (r < 0)
return r;
@ -4667,6 +4675,36 @@ static int run_container(
/* Normally redundant, but better safe than sorry */
(void) kill(*pid, SIGKILL);
if (arg_private_network) {
/* Move network interfaces back to the parent network namespace. We use `safe_fork`
* to avoid having to move the parent to the child network namespace. */
r = safe_fork(NULL, FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_WAIT|FORK_LOG, NULL);
if (r < 0)
return r;
if (r == 0) {
_cleanup_close_ int parent_netns_fd = -1;
r = namespace_open(getpid(), NULL, NULL, &parent_netns_fd, NULL, NULL);
if (r < 0) {
log_error_errno(r, "Failed to open parent network namespace: %m");
_exit(EXIT_FAILURE);
}
r = namespace_enter(-1, -1, child_netns_fd, -1, -1);
if (r < 0) {
log_error_errno(r, "Failed to enter child network namespace: %m");
_exit(EXIT_FAILURE);
}
r = move_network_interfaces(parent_netns_fd, arg_network_interfaces);
if (r < 0)
log_error_errno(r, "Failed to move network interfaces back to parent network namespace: %m");
_exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
}
}
r = wait_for_container(*pid, &container_status);
*pid = 0;