Hello Luigi,
I am a Software Engineer at Freescale semiconductor and I am currently working
on porting netmap to Freescale's integrated network controller ETSEC. I came
across the segmentation problem while testing my port with pkt-gen application
provided as an example. This segmentation fault is due to the buffer pointer
return to user space which is beyond the address space of the application. The
reason for this I believe is line number 1351 in file netmap_mem2.c
*(uint16_t *)(uintptr_t)&ring->nr_buf_size =
netmap_mem_bufsize(na->nm_mem);
where nr_buf_size is a 32 bit integer but we are storing the buffer size while
casting this variable to a 16 bit integer pointer. When userspace application
requests the buffer address we read this variable as a 32 bit integer and apply
that as the offset.
Though this works on little endian systems because how they store the value in
memory, it breaks in big endian systems. The cast can be changed to 32 bit
integer pointer to make netmap more stable across different platforms.
Thank you,
Sumith Dev Vojini
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