If controller received bad frames make sure to update newly added

RFA. Also drop frames that have either CRC error or alignment
error. Normally bad frames are not received at all. But controllers
running in promiscuous mode will receive bad frames. 82557 will
also receive bad frames to receive VLAN oversized frames.

While I'm here mark RNR condition if driver happen to see RNR in
RFA status and restart RU to receive frames again. Because driver
checks all received frames in RX loop, RNR condition could be set
in the middle of RX processing. Just relying on RNR interrupt was
not enough.

This change fixes "Memory modified after free" issue when fxp(4)
is running as a member of if_bridge(4).

Tested by:	Larry Baird <lab <> gta dot com>
MFC after:	5 days

1 files changed, 7 insertions, 2 deletions

diff --git a/sys/dev/fxp/if_fxp.c b/sys/dev/fxp/if_fxp.c
index 006ec526b59a..079ecc1e82d9 100644
--- a/sys/dev/fxp/if_fxp.c
+++ b/sys/dev/fxp/if_fxp.c
@@ -1916,6 +1916,8 @@ fxp_intr_body(struct fxp_softc *sc, struct ifnet *ifp, uint8_t statack,
 		if ((status & FXP_RFA_STATUS_C) == 0)
 			break;
 
+		if ((status & FXP_RFA_STATUS_RNR) != 0)
+			rnr++;
 		/*
 		 * Advance head forward.
 		 */
@@ -1942,9 +1944,12 @@ fxp_intr_body(struct fxp_softc *sc, struct ifnet *ifp, uint8_t statack,
 				total_len -= 2;
 			}
 			if (total_len < sizeof(struct ether_header) ||
-			    total_len > MCLBYTES - RFA_ALIGNMENT_FUDGE -
-				sc->rfa_size || status & FXP_RFA_STATUS_CRC) {
+			    total_len > (MCLBYTES - RFA_ALIGNMENT_FUDGE -
+			    sc->rfa_size) ||
+			    status & (FXP_RFA_STATUS_CRC |
+			    FXP_RFA_STATUS_ALIGN)) {
 				m_freem(m);
+				fxp_add_rfabuf(sc, rxp);
 				continue;
 			}