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[Qemu-devel] [RFC PATCH] net/net: Record usage status of mac address
From: |
Shannon Zhao |
Subject: |
[Qemu-devel] [RFC PATCH] net/net: Record usage status of mac address |
Date: |
Thu, 21 May 2015 17:44:48 +0800 |
From: Shannon Zhao <address@hidden>
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 <address@hidden>
Signed-off-by: Shannon Zhao <address@hidden>
---
net/net.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 55 insertions(+), 4 deletions(-)
diff --git a/net/net.c b/net/net.c
index 0be084d..7f0646e 100644
--- a/net/net.c
+++ b/net/net.c
@@ -160,19 +160,68 @@ 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);
}
/**
@@ -367,6 +416,8 @@ 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++) {
--
2.0.4
- [Qemu-devel] [RFC PATCH] net/net: Record usage status of mac address,
Shannon Zhao <=