shaba/systemd
1
0
Fork 0
mirror of https://github.com/systemd/systemd.git synced 2025-01-12 13:18:14 +03:00
Code

nspawn: make host0's MAC address persistent

Browse Source 
We still need to make sure that no two MAC addresses are the same, so we use
a logic similar to what is used in udev to generate MAC addresses, and base
it on a hash of the host's machine ID and thecontainer's name.
This commit is contained in:
Tom Gundersen 2014-03-13 17:47:30 +01:00
parent fc6c7fe9be
commit 01dde0611b
1 changed files with 50 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
src/nspawn/nspawn.c
View File

@ -86,6 +86,7 @@
#include "udev-util.h"
#include "blkid-util.h"
#include "gpt.h"
#include "siphash24.h"
#ifdef HAVE_SECCOMP
#include "seccomp-util.h"
@ -1399,9 +1400,46 @@ static int reset_audit_loginuid(void) {
return 0;
}
#define HASH_KEY SD_ID128_MAKE(c3,c4,f9,19,b5,57,b2,1c,e6,cf,14,27,03,9c,ee,a2)
static int get_mac(struct ether_addr *mac) {
int r;
uint8_t result[8];
size_t l, sz;
uint8_t *v;
l = strlen(arg_machine);
sz = sizeof(sd_id128_t) + l;
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 */
memcpy(v + sizeof(sd_id128_t), arg_machine, l);
/* Let's hash the host machine ID plus the container name. We
* use a fixed, but originally randomly created hash key here. */
siphash24(result, 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 setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
_cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
struct ether_addr mac;
int r;
if (!arg_private_network)
@ -1416,9 +1454,14 @@ static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) {
memcpy(iface_name, "vb-", 3);
else
memcpy(iface_name, "ve-", 3);
strncpy(iface_name+3, arg_machine, IFNAMSIZ - 3);
r = get_mac(&mac);
if (r < 0) {
log_error("Failed to generate predictable MAC address for host0");
return r;
}
r = sd_rtnl_open(&rtnl, 0);
if (r < 0) {
log_error("Failed to connect to netlink: %s", strerror(-r));
@ -1467,6 +1510,12 @@ static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) {
return r;
}
r = sd_rtnl_message_append_ether_addr(m, IFLA_ADDRESS, &mac);
if (r < 0) {
log_error("Failed to add netlink MAC address: %s", strerror(-r));
return r;
}
r = sd_rtnl_message_append_u32(m, IFLA_NET_NS_PID, pid);
if (r < 0) {
log_error("Failed to add netlink namespace field: %s", strerror(-r));