[43/43] e1000: Discard packets that are too long if !SBP and !LPE

Submitted by Michael Roth on Dec. 3, 2012, 10:44 p.m.

Details

Message ID 1354574681-28954-11-git-send-email-mdroth@linux.vnet.ibm.com
State New
Headers show

Commit Message

Michael Roth Dec. 3, 2012, 10:44 p.m.
From: Michael Contreras <michael@inetric.com>

The e1000_receive function for the e1000 needs to discard packets longer than
1522 bytes if the SBP and LPE flags are disabled. The linux driver assumes
this behavior and allocates memory based on this assumption.

Signed-off-by: Michael Contreras <michael@inetric.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
(cherry picked from commit b0d9ffcd0251161c7c92f94804dcf599dfa3edeb)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/e1000.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

Patch hide | download patch | download mbox

diff --git a/hw/e1000.c b/hw/e1000.c
index 4d4ac32..b1d8508 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -59,6 +59,9 @@  static int debugflags = DBGBIT(TXERR) | DBGBIT(GENERAL);
 #define PNPMMIO_SIZE      0x20000
 #define MIN_BUF_SIZE      60 /* Min. octets in an ethernet frame sans FCS */
 
+/* this is the size past which hardware will drop packets when setting LPE=0 */
+#define MAXIMUM_ETHERNET_VLAN_SIZE 1522
+
 /*
  * HW models:
  *  E1000_DEV_ID_82540EM works with Windows and Linux
@@ -795,6 +798,13 @@  e1000_receive(NetClientState *nc, const uint8_t *buf, size_t size)
         size = sizeof(min_buf);
     }
 
+    /* Discard oversized packets if !LPE and !SBP. */
+    if (size > MAXIMUM_ETHERNET_VLAN_SIZE
+        && !(s->mac_reg[RCTL] & E1000_RCTL_LPE)
+        && !(s->mac_reg[RCTL] & E1000_RCTL_SBP)) {
+        return size;
+    }
+
     if (!receive_filter(s, buf, size))
         return size;