Changeset 55922 in vbox

Timestamp:

May 19, 2015 3:04:59 AM (10 years ago)

Author:

vboxsync

Message:

DevPCNet: ASTRP_RCV bit is only for 802.3 frames, not Ethernet frames.
Data sheet mentions it elsewhere, but not in the documentation for the
bit itself. The code has always been incorrect, but r77259 broke it
further. The casualty was OpenStep, which now gets its network back.

File:

• trunk/src/VBox/Devices/Network/DevPCNet.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/Network/DevPCNet.cpp

@@ -1839 +1839 @@
         else
         {
+            PCRTNETETHERHDR pEth = (PCRTNETETHERHDR)buf;
+            bool fStrip = false;
+            size_t len_802_3;
             uint8_t   *src = &pThis->abRecvBuf[8];
             RTGCPHYS32 crda = CSR_CRDA(pThis);
@@ -1844 +1847 @@
             RMD        rmd, next_rmd;
 
+            /*
+             * Ethernet framing considers these two octets to be
+             * payload type; 802.3 framing considers them to be
+             * payload length.  IEEE 802.3x-1997 restricts Ethernet
+             * type to be greater than or equal to 1536 (0x0600), so
+             * that both framings can coexist on the wire.
+             *
+             * NB: CSR_ASTRP_RCV bit affects only 802.3 frames!
+             */
+            len_802_3 = RT_BE2H_U16(pEth->EtherType);
+            if (len_802_3 < 46 && CSR_ASTRP_RCV(pThis))
+            {
+                cbToRecv = RT_MIN(sizeof(RTNETETHERHDR) + len_802_3, cbToRecv);
+                fStrip = true;
+                fAddFCS = false;
+            }
+
             memcpy(src, buf, cbToRecv);
-            if (!CSR_ASTRP_RCV(pThis))
-            {
-                uint32_t fcs = ~0;
-                uint8_t *p = src;
-
+
+            if (!fStrip) {
                 while (cbToRecv < 60)
                     src[cbToRecv++] = 0;
+
                 if (fAddFCS)
                 {
+                    uint32_t fcs = ~0;
+                    uint8_t *p = src;
+
                     while (p != &src[cbToRecv])
                         CRC(fcs, *p++);
+
+                    /* FCS at the end of the packet */
                     ((uint32_t *)&src[cbToRecv])[0] = htonl(fcs);
-                    /* FCS at end of packet */
                     cbToRecv += 4;
                 }
             }
+
             cbPacket = (int)cbToRecv;                           Assert((size_t)cbPacket == cbToRecv);