[undi] Allow underlying PXE stack to construct link-layer header

Some PXE stacks (observed with a QLogic 8242) will always try to
prepend a link-layer header, even if the caller uses P_UNKNOWN to
indicate that the link-layer header has already been filled in.  This
results in an invalid packet being transmitted.

Work around these faulty PXE stacks where possible by stripping the
existing link-layer header and allowing the PXE stack to (re)construct
the link-layer header itself.

Originally-fixed-by: Buck Huppmann <buckh@pobox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/arch/i386/drivers/net/undinet.c b/src/arch/i386/drivers/net/undinet.c
index 63b373898e7745c2f8e20f16a8ce498e5d1aea35..190144156c42ea6646df9c229a9d0fc50d912cb0 100644 (file)
--- a/src/arch/i386/drivers/net/undinet.c
+++ b/src/arch/i386/drivers/net/undinet.c
@@ -20,6 +20,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <string.h>
 #include <unistd.h>
+#include <byteswap.h>
 #include <pxe.h>
 #include <realmode.h>
 #include <pic8259.h>
@@ -166,6 +167,10 @@ static int undinet_isr_triggered ( void ) {
 static struct s_PXENV_UNDI_TBD __data16 ( undinet_tbd );
 #define undinet_tbd __use_data16 ( undinet_tbd )
 
+/** UNDI transmit destination address */
+static uint8_t __data16_array ( undinet_destaddr, [ETH_ALEN] );
+#define undinet_destaddr __use_data16 ( undinet_destaddr )
+
 /**
  * Transmit packet
  *
@@ -175,8 +180,14 @@ static struct s_PXENV_UNDI_TBD __data16 ( undinet_tbd );
  */
 static int undinet_transmit ( struct net_device *netdev,
                              struct io_buffer *iobuf ) {
+       struct undi_nic *undinic = netdev->priv;
        struct s_PXENV_UNDI_TRANSMIT undi_transmit;
-       size_t len = iob_len ( iobuf );
+       const void *ll_dest;
+       const void *ll_source;
+       uint16_t net_proto;
+       unsigned int flags;
+       uint8_t protocol;
+       size_t len;
        int rc;
 
        /* Technically, we ought to make sure that the previous
@@ -189,15 +200,49 @@ static int undinet_transmit ( struct net_device *netdev,
         * transmit the next packet.
         */
 
+       /* Some PXE stacks are unable to cope with P_UNKNOWN, and will
+        * always try to prepend a link-layer header.  Work around
+        * these stacks by stripping the existing link-layer header
+        * and allowing the PXE stack to (re)construct the link-layer
+        * header itself.
+        */
+       if ( ( rc = eth_pull ( netdev, iobuf, &ll_dest, &ll_source,
+                              &net_proto, &flags ) ) != 0 ) {
+               DBGC ( undinic, "UNDINIC %p could not strip Ethernet header: "
+                      "%s\n", undinic, strerror ( rc ) );
+               return rc;
+       }
+       memcpy ( undinet_destaddr, ll_dest, sizeof ( undinet_destaddr ) );
+       switch ( net_proto ) {
+       case htons ( ETH_P_IP ) :
+               protocol = P_IP;
+               break;
+       case htons ( ETH_P_ARP ) :
+               protocol = P_ARP;
+               break;
+       case htons ( ETH_P_RARP ) :
+               protocol = P_RARP;
+               break;
+       default:
+               /* Unknown protocol; restore the original link-layer header */
+               iob_push ( iobuf, sizeof ( struct ethhdr ) );
+               protocol = P_UNKNOWN;
+               break;
+       }
+
        /* Copy packet to UNDI I/O buffer */
+       len = iob_len ( iobuf );
        if ( len > sizeof ( basemem_packet ) )
                len = sizeof ( basemem_packet );
        memcpy ( &basemem_packet, iobuf->data, len );
 
        /* Create PXENV_UNDI_TRANSMIT data structure */
        memset ( &undi_transmit, 0, sizeof ( undi_transmit ) );
+       undi_transmit.Protocol = protocol;
+       undi_transmit.XmitFlag = ( ( flags & LL_BROADCAST ) ?
+                                  XMT_BROADCAST : XMT_DESTADDR );
        undi_transmit.DestAddr.segment = rm_ds;
-       undi_transmit.DestAddr.offset = __from_data16 ( &undinet_tbd );
+       undi_transmit.DestAddr.offset = __from_data16 ( &undinet_destaddr );
        undi_transmit.TBD.segment = rm_ds;
        undi_transmit.TBD.offset = __from_data16 ( &undinet_tbd );
 

diff --git a/src/include/ipxe/ethernet.h b/src/include/ipxe/ethernet.h
index 7e49655a33d1dbd650795ad9897809e74bf70b27..3d2d462ef99fcd506e0e4c09c4c04459e940cb3c 100644 (file)
--- a/src/include/ipxe/ethernet.h
+++ b/src/include/ipxe/ethernet.h
@@ -10,6 +10,8 @@
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <stdint.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/iobuf.h>
 
 /**
  * Check if Ethernet address is all zeroes
@@ -77,6 +79,12 @@ static inline int is_valid_ether_addr ( const void *addr ) {
                 ( ! is_zero_ether_addr ( addr ) ) );
 }
 
+extern int eth_push ( struct net_device *netdev, struct io_buffer *iobuf,
+                     const void *ll_dest, const void *ll_source,
+                     uint16_t net_proto );
+extern int eth_pull ( struct net_device *netdev, struct io_buffer *iobuf,
+                     const void **ll_dest, const void **ll_source,
+                     uint16_t *net_proto, unsigned int *flags );
 extern void eth_init_addr ( const void *hw_addr, void *ll_addr );
 extern const char * eth_ntoa ( const void *ll_addr );
 extern int eth_mc_hash ( unsigned int af, const void *net_addr,

diff --git a/src/net/ethernet.c b/src/net/ethernet.c
index c63fd9bc341c7839fcd4f9ff1869aa847a29acd7..a842bc117dd70646f79a39d3b7c20ff2bab7526d 100644 (file)
--- a/src/net/ethernet.c
+++ b/src/net/ethernet.c
@@ -50,9 +50,9 @@ static uint8_t eth_broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  * @v net_proto                Network-layer protocol, in network-byte order
  * @ret rc             Return status code
  */
-static int eth_push ( struct net_device *netdev __unused,
-                     struct io_buffer *iobuf, const void *ll_dest,
-                     const void *ll_source, uint16_t net_proto ) {
+int eth_push ( struct net_device *netdev __unused, struct io_buffer *iobuf,
+              const void *ll_dest, const void *ll_source,
+              uint16_t net_proto ) {
        struct ethhdr *ethhdr = iob_push ( iobuf, sizeof ( *ethhdr ) );
 
        /* Build Ethernet header */
@@ -74,10 +74,9 @@ static int eth_push ( struct net_device *netdev __unused,
  * @ret flags          Packet flags
  * @ret rc             Return status code
  */
-static int eth_pull ( struct net_device *netdev __unused, 
-                     struct io_buffer *iobuf, const void **ll_dest,
-                     const void **ll_source, uint16_t *net_proto,
-                     unsigned int *flags ) {
+int eth_pull ( struct net_device *netdev __unused, struct io_buffer *iobuf,
+              const void **ll_dest, const void **ll_source,
+              uint16_t *net_proto, unsigned int *flags ) {
        struct ethhdr *ethhdr = iobuf->data;
 
        /* Sanity check */