net/net: Record usage status of mac address

Currently QEMU dynamically generates mac address for the NIC which
doesn't specify the mac address. But when we hotplug a NIC without
specifying mac address, the mac address will increase for the same NIC
along with hotplug and hot-unplug, and at last it will overflow. And if
we codeplug one NIC with mac address e.g. "52:54:00:12:34:56", then
hotplug one NIC without specifying mac address and the mac address of
the hotplugged NIC is duplicate of "52:54:00:12:34:56".

This patch add a mac_table to record the usage status and free the mac
address when the NIC is unrealized.

Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Shannon Zhao 2015-05-21 17:44:48 +08:00 committed by Stefan Hajnoczi
parent a308817743
commit 2bc22a58e1
1 changed files with 55 additions and 4 deletions

View File

@ -167,19 +167,68 @@ void qemu_format_nic_info_str(NetClientState *nc, uint8_t macaddr[6])
macaddr[3], macaddr[4], macaddr[5]);
}
static int mac_table[256] = {0};
static void qemu_macaddr_set_used(MACAddr *macaddr)
{
int index;
for (index = 0x56; index < 0xFF; index++) {
if (macaddr->a[5] == index) {
mac_table[index]++;
}
}
}
static void qemu_macaddr_set_free(MACAddr *macaddr)
{
int index;
static const MACAddr base = { .a = { 0x52, 0x54, 0x00, 0x12, 0x34, 0 } };
if (memcmp(macaddr->a, &base.a, (sizeof(base.a) - 1)) != 0) {
return;
}
for (index = 0x56; index < 0xFF; index++) {
if (macaddr->a[5] == index) {
mac_table[index]--;
}
}
}
static int qemu_macaddr_get_free(void)
{
int index;
for (index = 0x56; index < 0xFF; index++) {
if (mac_table[index] == 0) {
return index;
}
}
return -1;
}
void qemu_macaddr_default_if_unset(MACAddr *macaddr)
{
static int index = 0;
static const MACAddr zero = { .a = { 0,0,0,0,0,0 } };
static const MACAddr base = { .a = { 0x52, 0x54, 0x00, 0x12, 0x34, 0 } };
if (memcmp(macaddr, &zero, sizeof(zero)) != 0) {
if (memcmp(macaddr->a, &base.a, (sizeof(base.a) - 1)) != 0) {
return;
} else {
qemu_macaddr_set_used(macaddr);
return;
}
}
if (memcmp(macaddr, &zero, sizeof(zero)) != 0)
return;
macaddr->a[0] = 0x52;
macaddr->a[1] = 0x54;
macaddr->a[2] = 0x00;
macaddr->a[3] = 0x12;
macaddr->a[4] = 0x34;
macaddr->a[5] = 0x56 + index++;
macaddr->a[5] = qemu_macaddr_get_free();
qemu_macaddr_set_used(macaddr);
}
/**
@ -374,6 +423,8 @@ void qemu_del_nic(NICState *nic)
{
int i, queues = MAX(nic->conf->peers.queues, 1);
qemu_macaddr_set_free(&nic->conf->macaddr);
/* If this is a peer NIC and peer has already been deleted, free it now. */
if (nic->peer_deleted) {
for (i = 0; i < queues; i++) {