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authorJesse Brandeburg <jesse.brandeburg@intel.com>2008-02-21 15:11:02 -0800
committerJeff Garzik <jeff@garzik.org>2008-02-24 00:07:49 -0500
commitde92d84ec2305c490aa1db33f6e40680f8c236a8 (patch)
tree78298ae28581b04642313f1d78c968d1e53573e5 /drivers/net/e1000e/lib.c
parent4a5694e66428607585c9f4dd14bcf4158d2de191 (diff)
e1000e: fix flow control denial of service possibility
this patch avoids a denial of service from an evildoer sending a continuous stream of flow control at our adapter that is plugged into a non-flow control enabled switch. Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers/net/e1000e/lib.c')
-rw-r--r--drivers/net/e1000e/lib.c31
1 files changed, 5 insertions, 26 deletions
diff --git a/drivers/net/e1000e/lib.c b/drivers/net/e1000e/lib.c
index 0860b5fb347..341d74e81fb 100644
--- a/drivers/net/e1000e/lib.c
+++ b/drivers/net/e1000e/lib.c
@@ -1104,34 +1104,13 @@ s32 e1000e_config_fc_after_link_up(struct e1000_hw *hw)
(mii_nway_lp_ability_reg & NWAY_LPAR_ASM_DIR)) {
mac->fc = e1000_fc_rx_pause;
hw_dbg(hw, "Flow Control = RX PAUSE frames only.\r\n");
- }
- /* Per the IEEE spec, at this point flow control should be
- * disabled. However, we want to consider that we could
- * be connected to a legacy switch that doesn't advertise
- * desired flow control, but can be forced on the link
- * partner. So if we advertised no flow control, that is
- * what we will resolve to. If we advertised some kind of
- * receive capability (Rx Pause Only or Full Flow Control)
- * and the link partner advertised none, we will configure
- * ourselves to enable Rx Flow Control only. We can do
- * this safely for two reasons: If the link partner really
- * didn't want flow control enabled, and we enable Rx, no
- * harm done since we won't be receiving any PAUSE frames
- * anyway. If the intent on the link partner was to have
- * flow control enabled, then by us enabling RX only, we
- * can at least receive pause frames and process them.
- * This is a good idea because in most cases, since we are
- * predominantly a server NIC, more times than not we will
- * be asked to delay transmission of packets than asking
- * our link partner to pause transmission of frames.
- */
- else if ((mac->original_fc == e1000_fc_none) ||
- (mac->original_fc == e1000_fc_tx_pause)) {
+ } else {
+ /*
+ * Per the IEEE spec, at this point flow control
+ * should be disabled.
+ */
mac->fc = e1000_fc_none;
hw_dbg(hw, "Flow Control = NONE.\r\n");
- } else {
- mac->fc = e1000_fc_rx_pause;
- hw_dbg(hw, "Flow Control = RX PAUSE frames only.\r\n");
}
/* Now we need to do one last check... If we auto-