Fix TSO large receive offloading in ix(4).

Without this diff it might happen that content of different
TCP connection get mixed up, when reading coalesced buffers
from the receive ring.

Thanks, for a lot of testing effort to mbuhl.

OK mbuhl@

diff --git a/sys/dev/pci/if_ix.c b/sys/dev/pci/if_ix.c
index 550fdfd..b59ec28 100644 (file)
--- a/sys/dev/pci/if_ix.c
+++ b/sys/dev/pci/if_ix.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_ix.c,v 1.188 2022/08/30 19:52:58 benno Exp $       */
+/*     $OpenBSD: if_ix.c,v 1.189 2022/09/02 14:08:09 jan Exp $ */
 
 /******************************************************************************
 
@@ -3110,7 +3110,7 @@ ixgbe_rxeof(struct rx_ring *rxr)
        struct ixgbe_rx_buf     *rxbuf, *nxbuf;
        union ixgbe_adv_rx_desc *rxdesc;
        size_t                   dsize = sizeof(union ixgbe_adv_rx_desc);
-       int                      i, nextp;
+       int                      i, nextp, rsccnt;
 
        if (!ISSET(ifp->if_flags, IFF_RUNNING))
                return FALSE;
@@ -3149,6 +3149,9 @@ ixgbe_rxeof(struct rx_ring *rxr)
                hashtype =
                    lemtoh16(&rxdesc->wb.lower.lo_dword.hs_rss.pkt_info) &
                    IXGBE_RXDADV_RSSTYPE_MASK;
+               rsccnt = lemtoh32(&rxdesc->wb.lower.lo_dword.data) &
+                   IXGBE_RXDADV_RSCCNT_MASK;
+               rsccnt >>= IXGBE_RXDADV_RSCCNT_SHIFT;
 
                if (staterr & IXGBE_RXDADV_ERR_FRAME_ERR_MASK) {
                        if (rxbuf->fmp) {
@@ -3168,12 +3171,16 @@ ixgbe_rxeof(struct rx_ring *rxr)
                            rxr->last_desc_filled);
                }
 
-               /* Currently no HW RSC support of 82599 */
                if (!eop) {
                        /*
                         * Figure out the next descriptor of this frame.
                         */
-                       nextp = i + 1;
+                       if (rsccnt) {
+                               nextp = staterr & IXGBE_RXDADV_NEXTP_MASK;
+                               nextp >>= IXGBE_RXDADV_NEXTP_SHIFT;
+                       } else {
+                               nextp = i + 1;
+                       }
                        if (nextp == sc->num_rx_desc)
                                nextp = 0;
                        nxbuf = &rxr->rx_buffers[nextp];