Changeset 14695 in vbox for trunk/src/VBox/Devices/Network

Timestamp:

Nov 27, 2008 10:34:30 AM (16 years ago)

Author:

vboxsync

Message:

IntNet: Quick hack to force broadcast flag in DHCP requests on shared MAC.

File:

• trunk/src/VBox/Devices/Network/SrvIntNetR0.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/Network/SrvIntNetR0.cpp

@@ -1957 +1957 @@
 
 /**
+ * Detects and edits an DHCP packet arriving from the internal net.
+ *
+ * @param   pNetwork        The network the frame is being sent to.
+ * @param   pSG             Pointer to the gather list for the frame.
+ *                          The flags and data content may be updated.
+ * @param   pEthHdr         Pointer to the ethernet header. This may also be
+ *                          updated if it's a unicast...
+ */
+static void intnetR0NetworkEditDhcpFromIntNet(PINTNETNETWORK pNetwork, PINTNETSG pSG, PRTNETETHERHDR pEthHdr)
+{
+    /*
+     * Check the minimum size and get a linear copy of the thing to work on,
+     * using the temporary buffer if necessary.
+     */
+    if (RT_UNLIKELY(pSG->cbTotal < sizeof(RTNETETHERHDR) + RTNETIPV4_MIN_LEN + RTNETUDP_MIN_LEN + RTNETBOOTP_DHCP_MIN_LEN))
+        return;
+    /*
+     * Get a pointer to a linear copy of the full packet, using the
+     * temporary buffer if necessary.
+     */
+    PCRTNETIPV4 pIpHdr = (PCRTNETIPV4)((PCRTNETETHERHDR)pSG->aSegs[0].pv + 1);
+    size_t cbPacket = pSG->cbTotal - sizeof(RTNETETHERHDR);
+    if (pSG->cSegsUsed > 1)
+    {
+        cbPacket = RT_MIN(cbPacket, INTNETNETWORK_TMP_SIZE);
+        Log6(("intnetR0NetworkEditDhcpFromIntNet: Copying IPv4/UDP/DHCP pkt %u\n", cbPacket));
+        if (!intnetR0SgReadPart(pSG, sizeof(RTNETETHERHDR), cbPacket, pNetwork->pbTmp))
+            return;
+        //pSG->fFlags |= INTNETSG_FLAGS_PKT_CP_IN_TMP;
+        pIpHdr = (PCRTNETIPV4)pNetwork->pbTmp;
+    }
+
+    /*
+     * Validate the IP header and find the UDP packet.
+     */
+    if (!RTNetIPv4IsHdrValid(pIpHdr, cbPacket, pSG->cbTotal - sizeof(RTNETETHERHDR)))
+    {
+        Log6(("intnetR0NetworkEditDhcpFromIntNet: bad ip header\n"));
+        return;
+    }
+    size_t cbIpHdr = pIpHdr->ip_hl * 4;
+    if (    pIpHdr->ip_p != RTNETIPV4_PROT_UDP                               /* DHCP is UDP. */
+        ||  cbPacket < cbIpHdr + RTNETUDP_MIN_LEN + RTNETBOOTP_DHCP_MIN_LEN) /* Min DHCP packet len */
+        return;
+ 
+    size_t cbUdpPkt = cbPacket - cbIpHdr;
+    PCRTNETUDP pUdpHdr = (PCRTNETUDP)((uintptr_t)pIpHdr + cbIpHdr);
+    /* We are only interested in DHCP packets coming from client to server. */
+    if (    RT_BE2H_U16(pUdpHdr->uh_dport) != RTNETIPV4_PORT_BOOTPS
+         || RT_BE2H_U16(pUdpHdr->uh_sport) != RTNETIPV4_PORT_BOOTPC)
+        return;
+
+    /*
+     * Check if the DHCP message is valid and get the type.
+     */
+    if (!RTNetIPv4IsUDPValid(pIpHdr, pUdpHdr, pUdpHdr + 1, cbUdpPkt))
+    {
+        Log6(("intnetR0NetworkEditDhcpFromIntNet: Bad UDP packet\n"));
+        return;
+    }
+    PCRTNETBOOTP pDhcp = (PCRTNETBOOTP)(pUdpHdr + 1);
+    uint8_t MsgType;
+    if (!RTNetIPv4IsDHCPValid(pUdpHdr, pDhcp, cbUdpPkt - sizeof(*pUdpHdr), &MsgType))
+    {
+        Log6(("intnetR0NetworkEditDhcpFromIntNet: Bad DHCP packet\n"));
+        return;
+    }
+
+    switch (MsgType)
+    {
+        case RTNET_DHCP_MT_DISCOVER:
+        case RTNET_DHCP_MT_REQUEST:
+            Log6(("intnetR0NetworkEditDhcpFromIntNet: Setting broadcast flag in DHCP %#x, previously %x\n", MsgType, pDhcp->bp_flags));
+            if (!(pDhcp->bp_flags & RT_H2BE_U16_C(RTNET_DHCP_FLAG_BROADCAST)))
+            {
+                /* Patch flags */
+                uint16_t uFlags = pDhcp->bp_flags | RT_H2BE_U16_C(RTNET_DHCP_FLAG_BROADCAST);
+                intnetR0SgWritePart(pSG, (uint8_t*)&pDhcp->bp_flags - (uint8_t*)pIpHdr + sizeof(RTNETETHERHDR), sizeof(uFlags), &uFlags);
+                /* Patch UDP checksum */
+                uint32_t uChecksum = (uint32_t)~pUdpHdr->uh_sum + RT_H2BE_U16_C(RTNET_DHCP_FLAG_BROADCAST);
+                while (uChecksum >> 16)
+                    uChecksum = (uChecksum >> 16) + (uChecksum & 0xFFFF);
+                uChecksum = ~uChecksum;
+                intnetR0SgWritePart(pSG, (uint8_t*)&pUdpHdr->uh_sum - (uint8_t*)pIpHdr + sizeof(RTNETETHERHDR), sizeof(pUdpHdr->uh_sum), &uChecksum);
+            }
+            break;
+    }
+}
+
+
+/**
  * Sends a broadcast frame.
  *
@@ -1981 +2072 @@
         &&  RT_BE2H_U16(pEthHdr->EtherType) == RTNET_ETHERTYPE_ARP)
         intnetR0NetworkEditArpFromWire(pNetwork, pSG, pEthHdr);
+
+     /*
+     * Check for DHCP packets from the internal net since we'll have to set
+     * broadcast flag in DHCP requests if we're sharing the MAC address with
+     * the host.
+     */
+    if (    (pNetwork->fFlags & INTNET_OPEN_FLAGS_SHARED_MAC_ON_WIRE)
+        &&  !fSrc
+        &&  RT_BE2H_U16(pEthHdr->EtherType) == RTNET_ETHERTYPE_IPV4)
+        intnetR0NetworkEditDhcpFromIntNet(pNetwork, pSG, pEthHdr);
 
     /*