1 /* SPDX-License-Identifier: LGPL-2.1+ */
5 #include <linux/veth.h>
10 #include "sd-netlink.h"
12 #include "alloc-util.h"
13 #include "ether-addr-util.h"
14 #include "lockfile-util.h"
15 #include "missing_network.h"
16 #include "netif-naming-scheme.h"
17 #include "netlink-util.h"
18 #include "nspawn-network.h"
19 #include "parse-util.h"
20 #include "siphash24.h"
21 #include "socket-util.h"
22 #include "stat-util.h"
23 #include "string-util.h"
25 #include "udev-util.h"
28 #define HOST_HASH_KEY SD_ID128_MAKE(1a,37,6f,c7,46,ec,45,0b,ad,a3,d5,31,06,60,5d,b1)
29 #define CONTAINER_HASH_KEY SD_ID128_MAKE(c3,c4,f9,19,b5,57,b2,1c,e6,cf,14,27,03,9c,ee,a2)
30 #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)
31 #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)
32 #define MACVLAN_HASH_KEY SD_ID128_MAKE(00,13,6d,bc,66,83,44,81,bb,0c,f9,51,1f,24,a6,6f)
33 #define SHORTEN_IFNAME_HASH_KEY SD_ID128_MAKE(e1,90,a4,04,a8,ef,4b,51,8c,cc,c3,3a,9f,11,fc,a2)
35 static int remove_one_link(sd_netlink
*rtnl
, const char *name
) {
36 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
42 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_DELLINK
, 0);
44 return log_error_errno(r
, "Failed to allocate netlink message: %m");
46 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, name
);
48 return log_error_errno(r
, "Failed to add netlink interface name: %m");
50 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
51 if (r
== -ENODEV
) /* Already gone */
54 return log_error_errno(r
, "Failed to remove interface %s: %m", name
);
59 static int generate_mac(
60 const char *machine_name
,
61 struct ether_addr
*mac
,
70 l
= strlen(machine_name
);
71 sz
= sizeof(sd_id128_t
) + l
;
75 v
= newa(uint8_t, sz
);
77 /* fetch some persistent data unique to the host */
78 r
= sd_id128_get_machine((sd_id128_t
*) v
);
82 /* combine with some data unique (on this host) to this
83 * container instance */
84 i
= mempcpy(v
+ sizeof(sd_id128_t
), machine_name
, l
);
87 memcpy(i
, &idx
, sizeof(idx
));
90 /* Let's hash the host machine ID plus the container name. We
91 * use a fixed, but originally randomly created hash key here. */
92 result
= htole64(siphash24(v
, sz
, hash_key
.bytes
));
94 assert_cc(ETH_ALEN
<= sizeof(result
));
95 memcpy(mac
->ether_addr_octet
, &result
, ETH_ALEN
);
97 /* see eth_random_addr in the kernel */
98 mac
->ether_addr_octet
[0] &= 0xfe; /* clear multicast bit */
99 mac
->ether_addr_octet
[0] |= 0x02; /* set local assignment bit (IEEE802) */
104 static int set_alternative_ifname(sd_netlink
*rtnl
, const char *ifname
, const char *altifname
) {
113 if (strlen(altifname
) >= ALTIFNAMSIZ
)
114 return log_warning_errno(SYNTHETIC_ERRNO(ERANGE
),
115 "Alternative interface name '%s' for '%s' is too long, ignoring",
118 r
= rtnl_set_link_alternative_names_by_ifname(&rtnl
, ifname
, STRV_MAKE(altifname
));
120 return log_warning_errno(r
,
121 "Failed to set alternative interface name '%s' to '%s', ignoring: %m",
130 const char *ifname_host
,
131 const char *altifname_host
,
132 const struct ether_addr
*mac_host
,
133 const char *ifname_container
,
134 const struct ether_addr
*mac_container
) {
136 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
142 assert(ifname_container
);
143 assert(mac_container
);
145 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_NEWLINK
, 0);
147 return log_error_errno(r
, "Failed to allocate netlink message: %m");
149 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, ifname_host
);
151 return log_error_errno(r
, "Failed to add netlink interface name: %m");
153 r
= sd_netlink_message_append_ether_addr(m
, IFLA_ADDRESS
, mac_host
);
155 return log_error_errno(r
, "Failed to add netlink MAC address: %m");
157 r
= sd_netlink_message_open_container(m
, IFLA_LINKINFO
);
159 return log_error_errno(r
, "Failed to open netlink container: %m");
161 r
= sd_netlink_message_open_container_union(m
, IFLA_INFO_DATA
, "veth");
163 return log_error_errno(r
, "Failed to open netlink container: %m");
165 r
= sd_netlink_message_open_container(m
, VETH_INFO_PEER
);
167 return log_error_errno(r
, "Failed to open netlink container: %m");
169 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, ifname_container
);
171 return log_error_errno(r
, "Failed to add netlink interface name: %m");
173 r
= sd_netlink_message_append_ether_addr(m
, IFLA_ADDRESS
, mac_container
);
175 return log_error_errno(r
, "Failed to add netlink MAC address: %m");
177 r
= sd_netlink_message_append_u32(m
, IFLA_NET_NS_PID
, pid
);
179 return log_error_errno(r
, "Failed to add netlink namespace field: %m");
181 r
= sd_netlink_message_close_container(m
);
183 return log_error_errno(r
, "Failed to close netlink container: %m");
185 r
= sd_netlink_message_close_container(m
);
187 return log_error_errno(r
, "Failed to close netlink container: %m");
189 r
= sd_netlink_message_close_container(m
);
191 return log_error_errno(r
, "Failed to close netlink container: %m");
193 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
195 return log_error_errno(r
, "Failed to add new veth interfaces (%s:%s): %m", ifname_host
, ifname_container
);
197 (void) set_alternative_ifname(rtnl
, ifname_host
, altifname_host
);
202 /* This is almost base64char(), but not entirely, as it uses the "url and filename safe" alphabet, since we
203 * don't want "/" appear in interface names (since interfaces appear in sysfs as filenames). See section #5
205 static char urlsafe_base64char(int x
) {
206 static const char table
[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
207 "abcdefghijklmnopqrstuvwxyz"
209 return table
[x
& 63];
212 static int shorten_ifname(char *ifname
) {
213 char new_ifname
[IFNAMSIZ
];
217 if (strlen(ifname
) < IFNAMSIZ
) /* Name is short enough */
220 if (naming_scheme_has(NAMING_NSPAWN_LONG_HASH
)) {
223 /* Calculate 64bit hash value */
224 h
= siphash24(ifname
, strlen(ifname
), SHORTEN_IFNAME_HASH_KEY
.bytes
);
226 /* Set the final four bytes (i.e. 32bit) to the lower 24bit of the hash, encoded in url-safe base64 */
227 memcpy(new_ifname
, ifname
, IFNAMSIZ
- 5);
228 new_ifname
[IFNAMSIZ
- 5] = urlsafe_base64char(h
>> 18);
229 new_ifname
[IFNAMSIZ
- 4] = urlsafe_base64char(h
>> 12);
230 new_ifname
[IFNAMSIZ
- 3] = urlsafe_base64char(h
>> 6);
231 new_ifname
[IFNAMSIZ
- 2] = urlsafe_base64char(h
);
233 /* On old nspawn versions we just truncated the name, provide compatibility */
234 memcpy(new_ifname
, ifname
, IFNAMSIZ
-1);
236 new_ifname
[IFNAMSIZ
- 1] = 0;
238 /* Log the incident to make it more discoverable */
239 log_warning("Network interface name '%s' has been changed to '%s' to fit length constraints.", ifname
, new_ifname
);
241 strcpy(ifname
, new_ifname
);
245 int setup_veth(const char *machine_name
,
247 char iface_name
[IFNAMSIZ
],
250 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
251 struct ether_addr mac_host
, mac_container
;
256 assert(machine_name
);
260 /* Use two different interface name prefixes depending whether
261 * we are in bridge mode or not. */
262 n
= strjoina(bridge
? "vb-" : "ve-", machine_name
);
263 r
= shorten_ifname(n
);
265 a
= strjoina(bridge
? "vb-" : "ve-", machine_name
);
267 r
= generate_mac(machine_name
, &mac_container
, CONTAINER_HASH_KEY
, 0);
269 return log_error_errno(r
, "Failed to generate predictable MAC address for container side: %m");
271 r
= generate_mac(machine_name
, &mac_host
, HOST_HASH_KEY
, 0);
273 return log_error_errno(r
, "Failed to generate predictable MAC address for host side: %m");
275 r
= sd_netlink_open(&rtnl
);
277 return log_error_errno(r
, "Failed to connect to netlink: %m");
279 r
= add_veth(rtnl
, pid
, n
, a
, &mac_host
, "host0", &mac_container
);
283 u
= if_nametoindex(n
);
285 return log_error_errno(errno
, "Failed to resolve interface %s: %m", n
);
287 strcpy(iface_name
, n
);
291 int setup_veth_extra(
292 const char *machine_name
,
296 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
301 assert(machine_name
);
304 if (strv_isempty(pairs
))
307 r
= sd_netlink_open(&rtnl
);
309 return log_error_errno(r
, "Failed to connect to netlink: %m");
311 STRV_FOREACH_PAIR(a
, b
, pairs
) {
312 struct ether_addr mac_host
, mac_container
;
314 r
= generate_mac(machine_name
, &mac_container
, VETH_EXTRA_CONTAINER_HASH_KEY
, idx
);
316 return log_error_errno(r
, "Failed to generate predictable MAC address for container side of extra veth link: %m");
318 r
= generate_mac(machine_name
, &mac_host
, VETH_EXTRA_HOST_HASH_KEY
, idx
);
320 return log_error_errno(r
, "Failed to generate predictable MAC address for host side of extra veth link: %m");
322 r
= add_veth(rtnl
, pid
, *a
, NULL
, &mac_host
, *b
, &mac_container
);
332 static int join_bridge(sd_netlink
*rtnl
, const char *veth_name
, const char *bridge_name
) {
333 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
340 r
= parse_ifindex_or_ifname(bridge_name
, &bridge_ifi
);
344 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_SETLINK
, 0);
348 r
= sd_rtnl_message_link_set_flags(m
, IFF_UP
, IFF_UP
);
352 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, veth_name
);
356 r
= sd_netlink_message_append_u32(m
, IFLA_MASTER
, bridge_ifi
);
360 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
367 static int create_bridge(sd_netlink
*rtnl
, const char *bridge_name
) {
368 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
371 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_NEWLINK
, 0);
375 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, bridge_name
);
379 r
= sd_netlink_message_open_container(m
, IFLA_LINKINFO
);
383 r
= sd_netlink_message_open_container_union(m
, IFLA_INFO_DATA
, "bridge");
387 r
= sd_netlink_message_close_container(m
);
391 r
= sd_netlink_message_close_container(m
);
395 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
402 int setup_bridge(const char *veth_name
, const char *bridge_name
, bool create
) {
403 _cleanup_(release_lock_file
) LockFile bridge_lock
= LOCK_FILE_INIT
;
404 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
411 r
= sd_netlink_open(&rtnl
);
413 return log_error_errno(r
, "Failed to connect to netlink: %m");
416 /* We take a system-wide lock here, so that we can safely check whether there's still a member in the
417 * bridge before removing it, without risking interference from other nspawn instances. */
419 r
= make_lock_file("/run/systemd/nspawn-network-zone", LOCK_EX
, &bridge_lock
);
421 return log_error_errno(r
, "Failed to take network zone lock: %m");
425 bridge_ifi
= join_bridge(rtnl
, veth_name
, bridge_name
);
428 if (bridge_ifi
!= -ENODEV
|| !create
|| n
> 10)
429 return log_error_errno(bridge_ifi
, "Failed to add interface %s to bridge %s: %m", veth_name
, bridge_name
);
431 /* Count attempts, so that we don't enter an endless loop here. */
434 /* The bridge doesn't exist yet. Let's create it */
435 r
= create_bridge(rtnl
, bridge_name
);
437 return log_error_errno(r
, "Failed to create bridge interface %s: %m", bridge_name
);
439 /* Try again, now that the bridge exists */
443 int remove_bridge(const char *bridge_name
) {
444 _cleanup_(release_lock_file
) LockFile bridge_lock
= LOCK_FILE_INIT
;
445 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
449 /* Removes the specified bridge, but only if it is currently empty */
451 if (isempty(bridge_name
))
454 r
= make_lock_file("/run/systemd/nspawn-network-zone", LOCK_EX
, &bridge_lock
);
456 return log_error_errno(r
, "Failed to take network zone lock: %m");
458 path
= strjoina("/sys/class/net/", bridge_name
, "/brif");
460 r
= dir_is_empty(path
);
461 if (r
== -ENOENT
) /* Already gone? */
464 return log_error_errno(r
, "Can't detect if bridge %s is empty: %m", bridge_name
);
465 if (r
== 0) /* Still populated, leave it around */
468 r
= sd_netlink_open(&rtnl
);
470 return log_error_errno(r
, "Failed to connect to netlink: %m");
472 return remove_one_link(rtnl
, bridge_name
);
475 static int parse_interface(const char *name
) {
478 r
= parse_ifindex_or_ifname(name
, &ifi
);
480 return log_error_errno(r
, "Failed to resolve interface %s: %m", name
);
485 int test_network_interface_initialized(const char *name
) {
486 _cleanup_(sd_device_unrefp
) sd_device
*d
= NULL
;
488 char ifi_str
[2 + DECIMAL_STR_MAX(int)];
490 if (path_is_read_only_fs("/sys"))
493 /* udev should be around. */
495 ifi
= parse_interface(name
);
499 sprintf(ifi_str
, "n%i", ifi
);
500 r
= sd_device_new_from_device_id(&d
, ifi_str
);
502 return log_error_errno(r
, "Failed to get device %s: %m", name
);
504 r
= sd_device_get_is_initialized(d
);
506 return log_error_errno(r
, "Failed to determine whether interface %s is initialized: %m", name
);
508 return log_error_errno(SYNTHETIC_ERRNO(EBUSY
), "Network interface %s is not initialized yet.", name
);
510 r
= device_is_renaming(d
);
512 return log_error_errno(r
, "Failed to determine the interface %s is being renamed: %m", name
);
514 return log_error_errno(SYNTHETIC_ERRNO(EBUSY
), "Interface %s is being renamed.", name
);
519 int move_network_interfaces(int netns_fd
, char **ifaces
) {
520 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
524 if (strv_isempty(ifaces
))
527 r
= sd_netlink_open(&rtnl
);
529 return log_error_errno(r
, "Failed to connect to netlink: %m");
531 STRV_FOREACH(i
, ifaces
) {
532 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
535 ifi
= parse_interface(*i
);
539 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_SETLINK
, ifi
);
541 return log_error_errno(r
, "Failed to allocate netlink message: %m");
543 r
= sd_netlink_message_append_u32(m
, IFLA_NET_NS_FD
, netns_fd
);
545 return log_error_errno(r
, "Failed to append namespace fd to netlink message: %m");
547 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
549 return log_error_errno(r
, "Failed to move interface %s to namespace: %m", *i
);
555 int setup_macvlan(const char *machine_name
, pid_t pid
, char **ifaces
) {
556 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
561 if (strv_isempty(ifaces
))
564 r
= sd_netlink_open(&rtnl
);
566 return log_error_errno(r
, "Failed to connect to netlink: %m");
568 STRV_FOREACH(i
, ifaces
) {
569 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
570 _cleanup_free_
char *n
= NULL
, *a
= NULL
;
571 struct ether_addr mac
;
574 ifi
= parse_interface(*i
);
578 r
= generate_mac(machine_name
, &mac
, MACVLAN_HASH_KEY
, idx
++);
580 return log_error_errno(r
, "Failed to create MACVLAN MAC address: %m");
582 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_NEWLINK
, 0);
584 return log_error_errno(r
, "Failed to allocate netlink message: %m");
586 r
= sd_netlink_message_append_u32(m
, IFLA_LINK
, ifi
);
588 return log_error_errno(r
, "Failed to add netlink interface index: %m");
590 n
= strjoin("mv-", *i
);
594 r
= shorten_ifname(n
);
596 a
= strjoin("mv-", *i
);
601 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, n
);
603 return log_error_errno(r
, "Failed to add netlink interface name: %m");
605 r
= sd_netlink_message_append_ether_addr(m
, IFLA_ADDRESS
, &mac
);
607 return log_error_errno(r
, "Failed to add netlink MAC address: %m");
609 r
= sd_netlink_message_append_u32(m
, IFLA_NET_NS_PID
, pid
);
611 return log_error_errno(r
, "Failed to add netlink namespace field: %m");
613 r
= sd_netlink_message_open_container(m
, IFLA_LINKINFO
);
615 return log_error_errno(r
, "Failed to open netlink container: %m");
617 r
= sd_netlink_message_open_container_union(m
, IFLA_INFO_DATA
, "macvlan");
619 return log_error_errno(r
, "Failed to open netlink container: %m");
621 r
= sd_netlink_message_append_u32(m
, IFLA_MACVLAN_MODE
, MACVLAN_MODE_BRIDGE
);
623 return log_error_errno(r
, "Failed to append macvlan mode: %m");
625 r
= sd_netlink_message_close_container(m
);
627 return log_error_errno(r
, "Failed to close netlink container: %m");
629 r
= sd_netlink_message_close_container(m
);
631 return log_error_errno(r
, "Failed to close netlink container: %m");
633 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
635 return log_error_errno(r
, "Failed to add new macvlan interfaces: %m");
637 (void) set_alternative_ifname(rtnl
, n
, a
);
643 int setup_ipvlan(const char *machine_name
, pid_t pid
, char **ifaces
) {
644 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
648 if (strv_isempty(ifaces
))
651 r
= sd_netlink_open(&rtnl
);
653 return log_error_errno(r
, "Failed to connect to netlink: %m");
655 STRV_FOREACH(i
, ifaces
) {
656 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*m
= NULL
;
657 _cleanup_free_
char *n
= NULL
, *a
= NULL
;
660 ifi
= parse_interface(*i
);
664 r
= sd_rtnl_message_new_link(rtnl
, &m
, RTM_NEWLINK
, 0);
666 return log_error_errno(r
, "Failed to allocate netlink message: %m");
668 r
= sd_netlink_message_append_u32(m
, IFLA_LINK
, ifi
);
670 return log_error_errno(r
, "Failed to add netlink interface index: %m");
672 n
= strjoin("iv-", *i
);
676 r
= shorten_ifname(n
);
678 a
= strjoin("iv-", *i
);
683 r
= sd_netlink_message_append_string(m
, IFLA_IFNAME
, n
);
685 return log_error_errno(r
, "Failed to add netlink interface name: %m");
687 r
= sd_netlink_message_append_u32(m
, IFLA_NET_NS_PID
, pid
);
689 return log_error_errno(r
, "Failed to add netlink namespace field: %m");
691 r
= sd_netlink_message_open_container(m
, IFLA_LINKINFO
);
693 return log_error_errno(r
, "Failed to open netlink container: %m");
695 r
= sd_netlink_message_open_container_union(m
, IFLA_INFO_DATA
, "ipvlan");
697 return log_error_errno(r
, "Failed to open netlink container: %m");
699 r
= sd_netlink_message_append_u16(m
, IFLA_IPVLAN_MODE
, IPVLAN_MODE_L2
);
701 return log_error_errno(r
, "Failed to add ipvlan mode: %m");
703 r
= sd_netlink_message_close_container(m
);
705 return log_error_errno(r
, "Failed to close netlink container: %m");
707 r
= sd_netlink_message_close_container(m
);
709 return log_error_errno(r
, "Failed to close netlink container: %m");
711 r
= sd_netlink_call(rtnl
, m
, 0, NULL
);
713 return log_error_errno(r
, "Failed to add new ipvlan interfaces: %m");
715 (void) set_alternative_ifname(rtnl
, n
, a
);
721 int veth_extra_parse(char ***l
, const char *p
) {
722 _cleanup_free_
char *a
= NULL
, *b
= NULL
;
725 r
= extract_first_word(&p
, &a
, ":", EXTRACT_DONT_COALESCE_SEPARATORS
);
728 if (r
== 0 || !ifname_valid(a
))
731 r
= extract_first_word(&p
, &b
, ":", EXTRACT_DONT_COALESCE_SEPARATORS
);
734 if (r
== 0 || !ifname_valid(b
)) {
744 r
= strv_push_pair(l
, a
, b
);
752 int remove_veth_links(const char *primary
, char **pairs
) {
753 _cleanup_(sd_netlink_unrefp
) sd_netlink
*rtnl
= NULL
;
757 /* In some cases the kernel might pin the veth links between host and container even after the namespace
758 * died. Hence, let's better remove them explicitly too. */
760 if (isempty(primary
) && strv_isempty(pairs
))
763 r
= sd_netlink_open(&rtnl
);
765 return log_error_errno(r
, "Failed to connect to netlink: %m");
767 remove_one_link(rtnl
, primary
);
769 STRV_FOREACH_PAIR(a
, b
, pairs
)
770 remove_one_link(rtnl
, *a
);