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nspawn: add new option "--port=" for exposing container ports on the local host

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This exposes an IP port on the container as local port using DNAT.
This commit is contained in:
Lennart Poettering
2015-01-13 13:55:15 +01:00
parent 5a8bcb674f
commit 6d0b55c272
5 changed files with 435 additions and 70 deletions
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src/nspawn/nspawn.c
+364 -58
View File
@@ -93,11 +93,22 @@
#include "cap-list.h"
#include "btrfs-util.h"
#include "machine-image.h"
#include "list.h"
#include "in-addr-util.h"
#include "fw-util.h"
#include "local-addresses.h"
#ifdef HAVE_SECCOMP
#include "seccomp-util.h"
#endif
typedef struct ExposePort {
int protocol;
uint16_t host_port;
uint16_t container_port;
LIST_FIELDS(struct ExposePort, ports);
} ExposePort;
typedef enum ContainerStatus {
CONTAINER_TERMINATED,
CONTAINER_REBOOTED
@@ -172,6 +183,7 @@ static const char *arg_network_bridge = NULL;
static unsigned long arg_personality = 0xffffffffLU;
static char *arg_image = NULL;
static Volatile arg_volatile = VOLATILE_NO;
static ExposePort *arg_expose_ports = NULL;
static void help(void) {
printf("%s [OPTIONS...] [PATH] [ARGUMENTS...]\n\n"
@@ -203,6 +215,8 @@ static void help(void) {
" Add a virtual ethernet connection between host\n"
" and container and add it to an existing bridge on\n"
" the host\n"
" -p --port=[PROTOCOL:]HOSTPORT[:CONTAINERPORT]\n"
" Expose a container IP port ont the host\n"
" -Z --selinux-context=SECLABEL\n"
" Set the SELinux security context to be used by\n"
" processes in the container\n"
@@ -225,8 +239,8 @@ static void help(void) {
" --register=BOOLEAN Register container as machine\n"
" --keep-unit Do not register a scope for the machine, reuse\n"
" the service unit nspawn is running in\n"
" --volatile[=MODE] Run the system in volatile mode\n",
program_invocation_short_name);
" --volatile[=MODE] Run the system in volatile mode\n"
, program_invocation_short_name);
}
static int set_sanitized_path(char **b, const char *path) {
@@ -309,6 +323,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "personality", required_argument, NULL, ARG_PERSONALITY },
{ "image", required_argument, NULL, 'i' },
{ "volatile", optional_argument, NULL, ARG_VOLATILE },
{ "port", required_argument, NULL, 'p' },
{}
};
@@ -318,7 +333,7 @@ static int parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "+hD:u:bL:M:jS:Z:qi:x", options, NULL)) >= 0)
while ((c = getopt_long(argc, argv, "+hD:u:bL:M:jS:Z:qi:xp:", options, NULL)) >= 0)
switch (c) {
@@ -643,6 +658,65 @@ static int parse_argv(int argc, char *argv[]) {
break;
case 'p': {
const char *split, *e;
uint16_t container_port, host_port;
int protocol;
ExposePort *p;
if ((e = startswith(optarg, "tcp:")))
protocol = IPPROTO_TCP;
else if ((e = startswith(optarg, "udp:")))
protocol = IPPROTO_UDP;
else {
e = optarg;
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) {
log_error("Failed to parse host port: %s", optarg);
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) {
log_error("Failed to parse host port: %s", optarg);
return -EINVAL;
}
LIST_FOREACH(ports, p, arg_expose_ports) {
if (p->protocol == protocol && p->host_port == host_port) {
log_error("Duplicate port specification: %s", optarg);
return -EINVAL;
}
}
p = new(ExposePort, 1);
if (!p)
return log_oom();
p->protocol = protocol;
p->host_port = host_port;
p->container_port = container_port;
LIST_PREPEND(ports, arg_expose_ports, p);
break;
}
case '?':
return -EINVAL;
@@ -698,6 +772,11 @@ static int parse_argv(int argc, char *argv[]) {
return -EINVAL;
}
if (arg_expose_ports && !arg_private_network) {
log_error("Cannot use --port= without private networking.");
return -EINVAL;
}
arg_retain = (arg_retain | plus | (arg_private_network ? 1ULL << CAP_NET_ADMIN : 0)) & ~minus;
return 1;
@@ -1349,8 +1428,8 @@ static int setup_dev_console(const char *dest, const char *console) {
static int setup_kmsg(const char *dest, int kmsg_socket) {
_cleanup_free_ char *from = NULL, *to = NULL;
int r, fd, k;
_cleanup_umask_ mode_t u;
int r, fd, k;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int))];
@@ -1401,7 +1480,7 @@ static int setup_kmsg(const char *dest, int kmsg_socket) {
/* Store away the fd in the socket, so that it stays open as
* long as we run the child */
k = sendmsg(kmsg_socket, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
k = sendmsg(kmsg_socket, &mh, MSG_NOSIGNAL);
safe_close(fd);
if (k < 0)
@@ -1412,6 +1491,198 @@ static int setup_kmsg(const char *dest, int kmsg_socket) {
return 0;
}
static int 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);
if (!arg_expose_ports)
return 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;
}
static int flush_ports(union in_addr_union *exposed) {
ExposePort *p;
int r, af = AF_INET;
assert(exposed);
if (!arg_expose_ports)
return 0;
if (in_addr_is_null(af, exposed))
return 0;
log_debug("Lost IP address.");
LIST_FOREACH(ports, p, arg_expose_ports) {
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;
}
static int expose_ports(sd_rtnl *rtnl, 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 (!arg_expose_ports)
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 flush_ports(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, arg_expose_ports) {
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;
}
static int on_address_change(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
union in_addr_union *exposed = userdata;
assert(rtnl);
assert(m);
assert(exposed);
expose_ports(rtnl, exposed);
return 0;
}
static int watch_rtnl(sd_event *event, int recv_fd, union in_addr_union *exposed, sd_rtnl **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_rtnl_unref_ sd_rtnl *rtnl = NULL;
int fd, r;
ssize_t k;
assert(event);
assert(recv_fd >= 0);
assert(ret);
if (!arg_expose_ports)
return 0;
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_rtnl_open_fd(&rtnl, fd, 1, RTNLGRP_IPV4_IFADDR);
if (r < 0) {
safe_close(fd);
return log_error_errno(r, "Failed to create rtnl object: %m");
}
r = sd_rtnl_add_match(rtnl, RTM_NEWADDR, on_address_change, exposed);
if (r < 0)
return log_error_errno(r, "Failed to subscribe to RTM_NEWADDR messages: %m");
r = sd_rtnl_add_match(rtnl, RTM_DELADDR, on_address_change, exposed);
if (r < 0)
return log_error_errno(r, "Failed to subscribe to RTM_DELADDR messages: %m");
r = sd_rtnl_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;
}
static int setup_hostname(void) {
if (arg_share_system)
@@ -3059,7 +3330,6 @@ int main(int argc, char *argv[]) {
_cleanup_free_ char *device_path = NULL, *root_device = NULL, *home_device = NULL, *srv_device = NULL, *console = NULL;
bool root_device_rw = true, home_device_rw = true, srv_device_rw = true;
_cleanup_close_ int master = -1, image_fd = -1;
_cleanup_close_pair_ int kmsg_socket_pair[2] = { -1, -1 };
_cleanup_fdset_free_ FDSet *fds = NULL;
int r, n_fd_passed, loop_nr = -1;
char veth_name[IFNAMSIZ];
@@ -3067,6 +3337,7 @@ int main(int argc, char *argv[]) {
sigset_t mask, mask_chld;
pid_t pid = 0;
int ret = EXIT_SUCCESS;
union in_addr_union exposed = {};
log_parse_environment();
log_open();
@@ -3233,11 +3504,6 @@ int main(int argc, char *argv[]) {
goto finish;
}
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, kmsg_socket_pair) < 0) {
r = log_error_errno(errno, "Failed to create kmsg socket pair: %m");
goto finish;
}
assert_se(sigemptyset(&mask) == 0);
sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
@@ -3246,6 +3512,7 @@ int main(int argc, char *argv[]) {
assert_se(sigaddset(&mask_chld, SIGCHLD) == 0);
for (;;) {
_cleanup_close_pair_ int kmsg_socket_pair[2] = { -1, -1 }, rtnl_socket_pair[2] = { -1, -1 };
ContainerStatus container_status;
_cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL;
struct sigaction sa = {
@@ -3259,6 +3526,16 @@ int main(int argc, char *argv[]) {
goto finish;
}
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, kmsg_socket_pair) < 0) {
r = log_error_errno(errno, "Failed to create kmsg socket pair: %m");
goto finish;
}
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, rtnl_socket_pair) < 0) {
r = log_error_errno(errno, "Failed to create rtnl socket pair: %m");
goto finish;
}
/* Child can be killed before execv(), so handle SIGCHLD
* in order to interrupt parent's blocking calls and
* give it a chance to call wait() and terminate. */
@@ -3317,6 +3594,7 @@ int main(int argc, char *argv[]) {
close_nointr(STDERR_FILENO);
kmsg_socket_pair[0] = safe_close(kmsg_socket_pair[0]);
rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
reset_all_signal_handlers();
reset_signal_mask();
@@ -3412,9 +3690,12 @@ int main(int argc, char *argv[]) {
if (setup_kmsg(arg_directory, kmsg_socket_pair[1]) < 0)
_exit(EXIT_FAILURE);
kmsg_socket_pair[1] = safe_close(kmsg_socket_pair[1]);
if (send_rtnl(rtnl_socket_pair[1]) < 0)
_exit(EXIT_FAILURE);
rtnl_socket_pair[1] = safe_close(rtnl_socket_pair[1]);
/* Tell the parent that we are ready, and that
* it can cgroupify us to that we lack access
* to certain devices and resources. */
@@ -3585,13 +3866,13 @@ int main(int argc, char *argv[]) {
fdset_free(fds);
fds = NULL;
kmsg_socket_pair[1] = safe_close(kmsg_socket_pair[1]);
rtnl_socket_pair[1] = safe_close(rtnl_socket_pair[1]);
/* Wait for the most basic Child-setup to be done,
* before we add hardware to it, and place it in a
* cgroup. */
if (barrier_sync_next(&barrier)) {
_cleanup_event_unref_ sd_event *event = NULL;
_cleanup_(pty_forward_freep) PTYForward *forward = NULL;
char last_char = 0;
int ifi = 0;
r = move_network_interfaces(pid);
@@ -3631,52 +3912,67 @@ int main(int argc, char *argv[]) {
(void) barrier_place(&barrier);
/* And wait that the child is completely ready now. */
(void) barrier_place_and_sync(&barrier);
if (barrier_place_and_sync(&barrier)) {
_cleanup_event_unref_ sd_event *event = NULL;
_cleanup_(pty_forward_freep) PTYForward *forward = NULL;
_cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
char last_char = 0;
sd_notify(false,
"READY=1\n"
"STATUS=Container running.");
sd_notify(false,
"READY=1\n"
"STATUS=Container running.");
r = sd_event_new(&event);
if (r < 0) {
log_error_errno(r, "Failed to get default event source: %m");
goto finish;
r = sd_event_new(&event);
if (r < 0) {
log_error_errno(r, "Failed to get default event source: %m");
goto finish;
}
if (arg_boot) {
/* Try to kill the init system on SIGINT or SIGTERM */
sd_event_add_signal(event, NULL, SIGINT, on_orderly_shutdown, UINT32_TO_PTR(pid));
sd_event_add_signal(event, NULL, SIGTERM, on_orderly_shutdown, UINT32_TO_PTR(pid));
} else {
/* Immediately exit */
sd_event_add_signal(event, NULL, SIGINT, NULL, NULL);
sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
}
/* simply exit on sigchld */
sd_event_add_signal(event, NULL, SIGCHLD, NULL, NULL);
if (arg_expose_ports) {
r = watch_rtnl(event, rtnl_socket_pair[0], &exposed, &rtnl);
if (r < 0)
goto finish;
(void) expose_ports(rtnl, &exposed);
}
rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
r = pty_forward_new(event, master, true, &forward);
if (r < 0) {
log_error_errno(r, "Failed to create PTY forwarder: %m");
goto finish;
}
r = sd_event_loop(event);
if (r < 0) {
log_error_errno(r, "Failed to run event loop: %m");
goto finish;
}
pty_forward_get_last_char(forward, &last_char);
forward = pty_forward_free(forward);
if (!arg_quiet && last_char != '\n')
putc('\n', stdout);
/* Kill if it is not dead yet anyway */
terminate_machine(pid);
}
if (arg_boot) {
/* Try to kill the init system on SIGINT or SIGTERM */
sd_event_add_signal(event, NULL, SIGINT, on_orderly_shutdown, UINT32_TO_PTR(pid));
sd_event_add_signal(event, NULL, SIGTERM, on_orderly_shutdown, UINT32_TO_PTR(pid));
} else {
/* Immediately exit */
sd_event_add_signal(event, NULL, SIGINT, NULL, NULL);
sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
}
/* simply exit on sigchld */
sd_event_add_signal(event, NULL, SIGCHLD, NULL, NULL);
r = pty_forward_new(event, master, true, &forward);
if (r < 0) {
log_error_errno(r, "Failed to create PTY forwarder: %m");
goto finish;
}
r = sd_event_loop(event);
if (r < 0) {
log_error_errno(r, "Failed to run event loop: %m");
goto finish;
}
pty_forward_get_last_char(forward, &last_char);
forward = pty_forward_free(forward);
if (!arg_quiet && last_char != '\n')
putc('\n', stdout);
/* Kill if it is not dead yet anyway */
terminate_machine(pid);
}
/* Normally redundant, but better safe than sorry */
@@ -3714,6 +4010,8 @@ int main(int argc, char *argv[]) {
r = 0;
break;
}
flush_ports(&exposed);
}
finish:
@@ -3753,5 +4051,13 @@ finish:
strv_free(arg_bind_ro);
strv_free(arg_tmpfs);
flush_ports(&exposed);
while (arg_expose_ports) {
ExposePort *p = arg_expose_ports;
LIST_REMOVE(ports, arg_expose_ports, p);
free(p);
}
return r < 0 ? EXIT_FAILURE : ret;
}