Re: [ECOS] IPv6 on synth over TAP interface

[Andrew Lunn <andrew dot lunn at ascom dot ch>]

> IPv6 requires multicast support, i.e. it needs additional
> functionality from the ethernet device driver.
> 
....

> Not all real
> ethernet cards will support multicasts, so during initialization there
> is a message from rawether to the eCos ecosynth driver containing a
> multicast_supported flag (plus other info like the MAC address). The
> eCos driver then uses that information when processing the SET_MC_ALL
> ioctl(). IIRC the tap device should always support multicasts.

I found part of the problem...

//
// This function supports "I/O control" operations on an interface.
//
static int  
eth_drv_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
...

    case SIOCDELMULTI:
    {
        struct ifmultiaddr *ifma;
        struct eth_drv_mc_list mc_list;
        int mode = (ifp->if_flags & IFF_ALLMULTI) ? ETH_DRV_SET_MC_ALL :
                                                    ETH_DRV_SET_MC_LIST;

So the eth_drv layer decided to either use *MC_ALL or *MC_LIST
depending on the interface flags. The synth driver only supports
*MC_ALL, so needs to set IFF_ALLMULTI in the flags. Without this, the
eth_drv uses the *MC_LIST option which the synth driver returns with
an error.

   Andrew

Index: devs/eth/synth//ecosynth/current/ChangeLog
===================================================================
RCS file: /cvs/ecos/ecos/packages/devs/eth/synth/ecosynth/current/ChangeLog,v
retrieving revision 1.8
diff -u -r1.8 ChangeLog
--- devs/eth/synth//ecosynth/current/ChangeLog  25 Feb 2003 16:46:23 -0000     1.8
+++ devs/eth/synth//ecosynth/current/ChangeLog  1 Apr 2003 07:44:43 -0000
@@ -1,3 +1,9 @@
+2003-04-01  Andrew Lunn  <andrew dot lunn at ascom dot ch>
+
+       * src/syntheth.c (synth_eth_init): Set the flag IFF_ALLMULTI so
+       eth_drv correctly sets mutlicast filtering.
+       * cdl/syntheth.cdl: This driver implements multicast.
+
 2003-02-25  Jonathan Larmour  <jifl at eCosCentric dot com>
 
        * doc/syntheth.sgml: Declare as <part> not <reference> to get
Index: devs/eth/synth//ecosynth/current/cdl/syntheth.cdl
===================================================================
RCS file: /cvs/ecos/ecos/packages/devs/eth/synth/ecosynth/current/cdl/syntheth.cdl,v
retrieving revision 1.4
diff -u -r1.4 syntheth.cdl
--- devs/eth/synth//ecosynth/current/cdl/syntheth.cdl   24 Feb 2003 14:09:19 -0000      1.4
+++ devs/eth/synth//ecosynth/current/cdl/syntheth.cdl   1 Apr 2003 07:44:44 -0000
@@ -64,6 +64,7 @@
     parent      CYGPKG_IO_ETH_DRIVERS
     active_if   CYGPKG_IO_ETH_DRIVERS
     active_if   CYGPKG_HAL_SYNTH
+    implements  CYGINT_IO_ETH_MULTICAST
 
     cdl_option CYGVAR_DEVS_ETH_ECOSYNTH_ETH0 {
        display         "Provide eth0 device"
Index: devs/eth/synth/ecosynth/current/src/syntheth.c
===================================================================
RCS file: /cvs/ecos/ecos/packages/devs/eth/synth/ecosynth/current/src/syntheth.c,v
retrieving revision 1.2
diff -u -r1.2 syntheth.c
--- devs/eth/synth/ecosynth/current/src/syntheth.c      13 Feb 2003 22:25:16 -0000      1.2
+++ devs/eth/synth/ecosynth/current/src/syntheth.c      1 Apr 2003 07:48:48 -0000
@@ -451,5 +451,9 @@
         }
     }
     (*sc->funs->eth_drv->init)(sc, eth->MAC);
+
+#ifdef CYGPKG_NET
+    sc->arpcom->ac_if |= IFF_ALLMULTI;
+#endif    
     return result;
 }