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Systemd/src/nspawn/nspawn-network.c
Lennart Poettering 4afd3348c7 tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy 
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.

With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.

The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).

This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.

Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:

       #define _cleanup_(function) __attribute__((cleanup(function)))

Or similar, to make the gcc feature easier to use.

Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.

See #2008.
2015-11-27 19:19:36 +01:00

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/*-*- 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 <linux/veth.h>
#include <net/if.h>
#include "libudev.h"
#include "sd-id128.h"
#include "sd-netlink.h"
#include "alloc-util.h"
#include "ether-addr-util.h"
#include "netlink-util.h"
#include "nspawn-network.h"
#include "siphash24.h"
#include "string-util.h"
#include "udev-util.h"
#include "util.h"
#define HOST_HASH_KEY SD_ID128_MAKE(1a,37,6f,c7,46,ec,45,0b,ad,a3,d5,31,06,60,5d,b1)
#define CONTAINER_HASH_KEY SD_ID128_MAKE(c3,c4,f9,19,b5,57,b2,1c,e6,cf,14,27,03,9c,ee,a2)
#define VETH_EXTRA_HOST_HASH_KEY SD_ID128_MAKE(48,c7,f6,b7,ea,9d,4c,9e,b7,28,d4,de,91,d5,bf,66)
#define VETH_EXTRA_CONTAINER_HASH_KEY SD_ID128_MAKE(af,50,17,61,ce,f9,4d,35,84,0d,2b,20,54,be,ce,59)
#define MACVLAN_HASH_KEY SD_ID128_MAKE(00,13,6d,bc,66,83,44,81,bb,0c,f9,51,1f,24,a6,6f)
static int generate_mac(
const char *machine_name,
struct ether_addr *mac,
sd_id128_t hash_key,
uint64_t idx) {
uint64_t result;
size_t l, sz;
uint8_t *v, *i;
int r;
l = strlen(machine_name);
sz = sizeof(sd_id128_t) + l;
if (idx > 0)
sz += sizeof(idx);
v = alloca(sz);
/* fetch some persistent data unique to the host */
r = sd_id128_get_machine((sd_id128_t*) v);
if (r < 0)
return r;
/* combine with some data unique (on this host) to this
* container instance */
i = mempcpy(v + sizeof(sd_id128_t), machine_name, l);
if (idx > 0) {
idx = htole64(idx);
memcpy(i, &idx, sizeof(idx));
}
/* Let's hash the host machine ID plus the container name. We
* use a fixed, but originally randomly created hash key here. */
result = htole64(siphash24(v, sz, hash_key.bytes));
assert_cc(ETH_ALEN <= sizeof(result));
memcpy(mac->ether_addr_octet, &result, ETH_ALEN);
/* see eth_random_addr in the kernel */
mac->ether_addr_octet[0] &= 0xfe; /* clear multicast bit */
mac->ether_addr_octet[0] |= 0x02; /* set local assignment bit (IEEE802) */
return 0;
}
static int add_veth(
sd_netlink *rtnl,
pid_t pid,
const char *ifname_host,
const struct ether_addr *mac_host,
const char *ifname_container,
const struct ether_addr *mac_container) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
int r;
assert(rtnl);
assert(ifname_host);
assert(mac_host);
assert(ifname_container);
assert(mac_container);
r = sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINK, 0);
if (r < 0)
return log_error_errno(r, "Failed to allocate netlink message: %m");
r = sd_netlink_message_append_string(m, IFLA_IFNAME, ifname_host);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface name: %m");
r = sd_netlink_message_append_ether_addr(m, IFLA_ADDRESS, mac_host);
if (r < 0)
return log_error_errno(r, "Failed to add netlink MAC address: %m");
r = sd_netlink_message_open_container(m, IFLA_LINKINFO);
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_open_container_union(m, IFLA_INFO_DATA, "veth");
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_open_container(m, VETH_INFO_PEER);
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_append_string(m, IFLA_IFNAME, ifname_container);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface name: %m");
r = sd_netlink_message_append_ether_addr(m, IFLA_ADDRESS, mac_container);
if (r < 0)
return log_error_errno(r, "Failed to add netlink MAC address: %m");
r = sd_netlink_message_append_u32(m, IFLA_NET_NS_PID, pid);
if (r < 0)
return log_error_errno(r, "Failed to add netlink namespace field: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_call(rtnl, m, 0, NULL);
if (r < 0)
return log_error_errno(r, "Failed to add new veth interfaces (%s:%s): %m", ifname_host, ifname_container);
return 0;
}
int setup_veth(const char *machine_name,
pid_t pid,
char iface_name[IFNAMSIZ],
bool bridge) {
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
struct ether_addr mac_host, mac_container;
int r, i;
assert(machine_name);
assert(pid > 0);
assert(iface_name);
/* Use two different interface name prefixes depending whether
* we are in bridge mode or not. */
snprintf(iface_name, IFNAMSIZ - 1, "%s-%s",
bridge ? "vb" : "ve", machine_name);
r = generate_mac(machine_name, &mac_container, CONTAINER_HASH_KEY, 0);
if (r < 0)
return log_error_errno(r, "Failed to generate predictable MAC address for container side: %m");
r = generate_mac(machine_name, &mac_host, HOST_HASH_KEY, 0);
if (r < 0)
return log_error_errno(r, "Failed to generate predictable MAC address for host side: %m");
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to connect to netlink: %m");
r = add_veth(rtnl, pid, iface_name, &mac_host, "host0", &mac_container);
if (r < 0)
return r;
i = (int) if_nametoindex(iface_name);
if (i <= 0)
return log_error_errno(errno, "Failed to resolve interface %s: %m", iface_name);
return i;
}
int setup_veth_extra(
const char *machine_name,
pid_t pid,
char **pairs) {
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
uint64_t idx = 0;
char **a, **b;
int r;
assert(machine_name);
assert(pid > 0);
if (strv_isempty(pairs))
return 0;
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to connect to netlink: %m");
STRV_FOREACH_PAIR(a, b, pairs) {
struct ether_addr mac_host, mac_container;
r = generate_mac(machine_name, &mac_container, VETH_EXTRA_CONTAINER_HASH_KEY, idx);
if (r < 0)
return log_error_errno(r, "Failed to generate predictable MAC address for container side of extra veth link: %m");
r = generate_mac(machine_name, &mac_host, VETH_EXTRA_HOST_HASH_KEY, idx);
if (r < 0)
return log_error_errno(r, "Failed to generate predictable MAC address for container side of extra veth link: %m");
r = add_veth(rtnl, pid, *a, &mac_host, *b, &mac_container);
if (r < 0)
return r;
idx ++;
}
return 0;
}
int setup_bridge(const char *veth_name, const char *bridge_name) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
int r, bridge_ifi;
assert(veth_name);
assert(bridge_name);
bridge_ifi = (int) if_nametoindex(bridge_name);
if (bridge_ifi <= 0)
return log_error_errno(errno, "Failed to resolve interface %s: %m", bridge_name);
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to connect to netlink: %m");
r = sd_rtnl_message_new_link(rtnl, &m, RTM_SETLINK, 0);
if (r < 0)
return log_error_errno(r, "Failed to allocate netlink message: %m");
r = sd_rtnl_message_link_set_flags(m, IFF_UP, IFF_UP);
if (r < 0)
return log_error_errno(r, "Failed to set IFF_UP flag: %m");
r = sd_netlink_message_append_string(m, IFLA_IFNAME, veth_name);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface name field: %m");
r = sd_netlink_message_append_u32(m, IFLA_MASTER, bridge_ifi);
if (r < 0)
return log_error_errno(r, "Failed to add netlink master field: %m");
r = sd_netlink_call(rtnl, m, 0, NULL);
if (r < 0)
return log_error_errno(r, "Failed to add veth interface to bridge: %m");
return bridge_ifi;
}
static int parse_interface(struct udev *udev, const char *name) {
_cleanup_udev_device_unref_ struct udev_device *d = NULL;
char ifi_str[2 + DECIMAL_STR_MAX(int)];
int ifi;
ifi = (int) if_nametoindex(name);
if (ifi <= 0)
return log_error_errno(errno, "Failed to resolve interface %s: %m", name);
sprintf(ifi_str, "n%i", ifi);
d = udev_device_new_from_device_id(udev, ifi_str);
if (!d)
return log_error_errno(errno, "Failed to get udev device for interface %s: %m", name);
if (udev_device_get_is_initialized(d) <= 0) {
log_error("Network interface %s is not initialized yet.", name);
return -EBUSY;
}
return ifi;
}
int move_network_interfaces(pid_t pid, char **ifaces) {
_cleanup_udev_unref_ struct udev *udev = NULL;
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
char **i;
int r;
if (strv_isempty(ifaces))
return 0;
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to connect to netlink: %m");
udev = udev_new();
if (!udev) {
log_error("Failed to connect to udev.");
return -ENOMEM;
}
STRV_FOREACH(i, ifaces) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
int ifi;
ifi = parse_interface(udev, *i);
if (ifi < 0)
return ifi;
r = sd_rtnl_message_new_link(rtnl, &m, RTM_SETLINK, ifi);
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);
if (r < 0)
return log_error_errno(r, "Failed to append namespace PID to netlink message: %m");
r = sd_netlink_call(rtnl, m, 0, NULL);
if (r < 0)
return log_error_errno(r, "Failed to move interface %s to namespace: %m", *i);
}
return 0;
}
int setup_macvlan(const char *machine_name, pid_t pid, char **ifaces) {
_cleanup_udev_unref_ struct udev *udev = NULL;
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
unsigned idx = 0;
char **i;
int r;
if (strv_isempty(ifaces))
return 0;
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to connect to netlink: %m");
udev = udev_new();
if (!udev) {
log_error("Failed to connect to udev.");
return -ENOMEM;
}
STRV_FOREACH(i, ifaces) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
_cleanup_free_ char *n = NULL;
struct ether_addr mac;
int ifi;
ifi = parse_interface(udev, *i);
if (ifi < 0)
return ifi;
r = generate_mac(machine_name, &mac, MACVLAN_HASH_KEY, idx++);
if (r < 0)
return log_error_errno(r, "Failed to create MACVLAN MAC address: %m");
r = sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINK, 0);
if (r < 0)
return log_error_errno(r, "Failed to allocate netlink message: %m");
r = sd_netlink_message_append_u32(m, IFLA_LINK, ifi);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface index: %m");
n = strappend("mv-", *i);
if (!n)
return log_oom();
strshorten(n, IFNAMSIZ-1);
r = sd_netlink_message_append_string(m, IFLA_IFNAME, n);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface name: %m");
r = sd_netlink_message_append_ether_addr(m, IFLA_ADDRESS, &mac);
if (r < 0)
return log_error_errno(r, "Failed to add netlink MAC address: %m");
r = sd_netlink_message_append_u32(m, IFLA_NET_NS_PID, pid);
if (r < 0)
return log_error_errno(r, "Failed to add netlink namespace field: %m");
r = sd_netlink_message_open_container(m, IFLA_LINKINFO);
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_open_container_union(m, IFLA_INFO_DATA, "macvlan");
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_append_u32(m, IFLA_MACVLAN_MODE, MACVLAN_MODE_BRIDGE);
if (r < 0)
return log_error_errno(r, "Failed to append macvlan mode: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_call(rtnl, m, 0, NULL);
if (r < 0)
return log_error_errno(r, "Failed to add new macvlan interfaces: %m");
}
return 0;
}
int setup_ipvlan(const char *machine_name, pid_t pid, char **ifaces) {
_cleanup_udev_unref_ struct udev *udev = NULL;
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
char **i;
int r;
if (strv_isempty(ifaces))
return 0;
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to connect to netlink: %m");
udev = udev_new();
if (!udev) {
log_error("Failed to connect to udev.");
return -ENOMEM;
}
STRV_FOREACH(i, ifaces) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
_cleanup_free_ char *n = NULL;
int ifi;
ifi = parse_interface(udev, *i);
if (ifi < 0)
return ifi;
r = sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINK, 0);
if (r < 0)
return log_error_errno(r, "Failed to allocate netlink message: %m");
r = sd_netlink_message_append_u32(m, IFLA_LINK, ifi);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface index: %m");
n = strappend("iv-", *i);
if (!n)
return log_oom();
strshorten(n, IFNAMSIZ-1);
r = sd_netlink_message_append_string(m, IFLA_IFNAME, n);
if (r < 0)
return log_error_errno(r, "Failed to add netlink interface name: %m");
r = sd_netlink_message_append_u32(m, IFLA_NET_NS_PID, pid);
if (r < 0)
return log_error_errno(r, "Failed to add netlink namespace field: %m");
r = sd_netlink_message_open_container(m, IFLA_LINKINFO);
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_open_container_union(m, IFLA_INFO_DATA, "ipvlan");
if (r < 0)
return log_error_errno(r, "Failed to open netlink container: %m");
r = sd_netlink_message_append_u16(m, IFLA_IPVLAN_MODE, IPVLAN_MODE_L2);
if (r < 0)
return log_error_errno(r, "Failed to add ipvlan mode: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_message_close_container(m);
if (r < 0)
return log_error_errno(r, "Failed to close netlink container: %m");
r = sd_netlink_call(rtnl, m, 0, NULL);
if (r < 0)
return log_error_errno(r, "Failed to add new ipvlan interfaces: %m");
}
return 0;
}
int veth_extra_parse(char ***l, const char *p) {
_cleanup_free_ char *a = NULL, *b = NULL;
int r;
r = extract_first_word(&p, &a, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
if (r < 0)
return r;
if (r == 0 || isempty(a))
return -EINVAL;
r = extract_first_word(&p, &b, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
if (r < 0)
return r;
if (r == 0 || isempty(b)) {
free(b);
b = strdup(a);
if (!b)
return -ENOMEM;
}
if (p)
return -EINVAL;
r = strv_push_pair(l, a, b);
if (r < 0)
return -ENOMEM;
a = b = NULL;
return 0;
}
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