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authorTom Gundersen <teg@jklm.no>2014-06-14 15:48:16 +0200
committerTom Gundersen <teg@jklm.no>2014-06-14 15:48:16 +0200
commit5c8f858d207992469bd65356e3e44d37fcefa4b0 (patch)
treee518b08d99b0e48d83f4efe99342a8b4c84bbeb7
parent96c907429e3224289fd360b8d9c8fdc573f4363b (diff)
Revert "Revert "networkd: netdev - set predictable mac address when creating netdev""
This reverts (and rewrites) commit 7d95c772cba1836545459760273b13f2e01dd2a8. The issue blocking this feature has now been fixed in the kernel, and backported to the various stable kernels. Our netdevs will now have stable MAC addresses, even if one is not specified.
-rw-r--r--src/network/networkd-netdev.c74
1 files changed, 73 insertions, 1 deletions
diff --git a/src/network/networkd-netdev.c b/src/network/networkd-netdev.c
index 0d08e564e5..5f8a82cbd2 100644
--- a/src/network/networkd-netdev.c
+++ b/src/network/networkd-netdev.c
@@ -27,6 +27,7 @@
#include "conf-files.h"
#include "conf-parser.h"
#include "list.h"
+#include "siphash24.h"
#define VLANID_MAX 4094
@@ -528,6 +529,52 @@ int netdev_set_ifindex(NetDev *netdev, sd_rtnl_message *message) {
return 0;
}
+#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(const char *ifname, struct ether_addr **ret) {
+ _cleanup_free_ struct ether_addr *mac = NULL;
+ uint8_t result[8];
+ size_t l, sz;
+ uint8_t *v;
+ int r;
+
+ assert(ifname);
+ assert(ret);
+
+ mac = new0(struct ether_addr, 1);
+ if (!mac)
+ return -ENOMEM;
+
+ l = strlen(ifname);
+ 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), ifname, 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) */
+
+ *ret = mac;
+ mac = NULL;
+
+ return 0;
+}
+
static int netdev_load_one(Manager *manager, const char *filename) {
_cleanup_netdev_unref_ NetDev *netdev = NULL;
_cleanup_fclose_ FILE *file = NULL;
@@ -607,14 +654,39 @@ static int netdev_load_one(Manager *manager, const char *filename) {
NULL, NULL, NULL, NULL, NULL, NULL) <= 0)
return 0;
+ if (!netdev->mac) {
+ r = netdev_get_mac(netdev->ifname, &netdev->mac);
+ if (r < 0) {
+ log_error("Failed to generate predictable MAC address for %s",
+ netdev->ifname);
+ return r;
+ }
+ }
+
r = hashmap_put(netdev->manager->netdevs, netdev->ifname, netdev);
if (r < 0)
return r;
LIST_HEAD_INIT(netdev->callbacks);
- if(netdev->kind == NETDEV_KIND_VETH)
+ if(netdev->kind == NETDEV_KIND_VETH) {
+ if (netdev->ifname_peer) {
+ log_warning("Veth NetDev without Peer Name configured "
+ "in %s. Ignoring", filename);
+ return 0;
+ }
+
+ if (!netdev->mac) {
+ r = netdev_get_mac(netdev->ifname_peer, &netdev->mac_peer);
+ if (r < 0) {
+ log_error("Failed to generate predictable MAC address for %s",
+ netdev->ifname_peer);
+ return r;
+ }
+ }
+
return netdev_create_veth(netdev, netdev_create_handler);
+ }
if (netdev->kind != NETDEV_KIND_VLAN &&
netdev->kind != NETDEV_KIND_MACVLAN &&