[lwip-devel] [bug #47270] [lwip-1.4.1 + ptp1588] - Multicast addresses for ptp domains

[Evripidis Karseras]

URL:
  <http://savannah.nongnu.org/bugs/?47270>

                 Summary: [lwip-1.4.1 + ptp1588] - Multicast addresses for ptp
domains
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: evripidis
            Submitted on: Fri 26 Feb 2016 01:06:38 GMT
                Category: IPv4
                Severity: 3 - Normal
              Item Group: Faulty Behaviour
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: 
            lwIP version: 1.4.1

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Details:

There is an issue in the following file:

lwip-1.4.1\src\core\ipv4\ip.c file (line 412)

        if (           ip_addr_cmp(&current_iphdr_dest, &(netif->ip_addr))
                ||     ip_addr_isbroadcast(&current_iphdr_dest, netif)
           )

There is no provision for multicast addresses needed for PTP1588. There is
another if statement before the above to account for IGMP and that is where
the multicast check is done. But PTP does not used IGMP flags so even by
enabling IGMP, the PTP packets never get through. 

This has been tested on a port for a T.I device and after the following
modification PTPD would work fine:

        if (           ip_addr_cmp(&current_iphdr_dest, &(netif->ip_addr))
                ||     ip_addr_isbroadcast(&current_iphdr_dest, netif)
#if    LWIP_PTPD
                ||     ip_addr_ismulticast(&current_iphdr_dest)
#endif /* LWIP_PTPD */
           )

Basically there is a clause added to make sure multicast is handled in case
PTPD is enabled.


Evripidis Karseras






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