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networkd: netdev - set predictable mac address when creating netdev

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This commit is contained in:
Tom Gundersen 2014-04-18 00:50:40 +02:00
parent 505f8da732
commit cdc85c875b
1 changed files with 55 additions and 0 deletions
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55
src/network/networkd-netdev.c
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@ -25,6 +25,7 @@
#include "conf-files.h"
#include "conf-parser.h"
#include "list.h"
#include "siphash24.h"
#define VLANID_MAX 4094
@ -180,8 +181,48 @@ static int netdev_create_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userda
return 1;
}
#define HASH_KEY SD_ID128_MAKE(52,e1,45,bd,00,6f,29,96,21,c6,30,6d,83,71,04,48)
static int netdev_get_mac(NetDev *netdev, struct ether_addr *mac) {
uint8_t result[8];
size_t l, sz;
uint8_t *v;
int r;
assert(netdev);
assert(netdev->name);
assert(mac);
l = strlen(netdev->name);
sz = sizeof(sd_id128_t) + l;
v = alloca(sz);
/* fetch some persistent data unique to the machine */
r = sd_id128_get_machine((sd_id128_t*) v);
if (r < 0)
return r;
/* combine with some data unique (on this machine) to this
* netdev */
memcpy(v + sizeof(sd_id128_t), netdev->name, 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 netdev_create(NetDev *netdev, Link *link, sd_rtnl_message_handler_t callback) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
struct ether_addr mac;
const char *kind;
int r;
@ -192,6 +233,12 @@ static int netdev_create(NetDev *netdev, Link *link, sd_rtnl_message_handler_t c
assert(netdev->manager);
assert(netdev->manager->rtnl);
r = netdev_get_mac(netdev, &mac);
if (r < 0) {
log_error("Failed to generate predictable MAC address for %s", netdev->name);
return r;
}
r = sd_rtnl_message_new_link(netdev->manager->rtnl, &req, RTM_NEWLINK, 0);
if (r < 0) {
log_error_netdev(netdev,
@ -218,6 +265,14 @@ static int netdev_create(NetDev *netdev, Link *link, sd_rtnl_message_handler_t c
return r;
}
r = sd_rtnl_message_append_ether_addr(req, IFLA_ADDRESS, &mac);
if (r < 0) {
log_error_netdev(netdev,
"Colud not append IFLA_ADDRESS attribute: %s",
strerror(-r));
return r;
}
r = sd_rtnl_message_open_container(req, IFLA_LINKINFO);
if (r < 0) {
log_error_netdev(netdev,