On Wed, Aug 31, 2022 at 5:12 AM Fotis Panagiotopoulos <f.j.pa...@gmail.com> wrote: > I enabled all network prints. > > I can see some ARP packets being sent and received, but nothing else. > I get a bunch of warnings like the following: > > netdriver_recv_work: WARNING: Unsupported Ethernet type 3465 > > (where the Ethernet type number is a different number every time)
This warning is printed from netdriver_recv_work() in arch/sim/src/sim/up_netdriver.c. The call to netdev_read() fills dev->d_buf, which is typecast to eth; then, eth->type is a 2-byte code located in bytes 12 and 13 of dev->d_buf. (See struct eth_hdr_s in include/nuttx/net/ethernet.h.) Since you're saying that the WARNING is printing a different number every time, I wonder whether the read in tapdev_read() is filling the buffer with random garbage. (Note: netdev_read() is a macro that translates to tapdev_read() under your Kconfig settings.) Following this line of thought... There is a symbol that isn't defined anywhere: TAPDEV_DEBUG. If this symbol is defined, then a function dump_ethhdr() will be called in tapdev_read(). (If not defined, which is the case now, then dump_ethhdr() is an empty macro.) It may be a good idea to define this symbol to help track down this problem by logging the received headers. The easiest way may be to temporarily add -DTAPDEV_DEBUG to CFLAGS in the board's Make.defs, but it might be better to rename this symbol to CONFIG_SIM_NETDEV_TAP_DEBUG and add it to arch/sim/Kconfig, so that other developers can turn it on and off easily. Now, in continuing to analyze where the data is coming from, I don't understand the implementation of tun_read() in drivers/net/tun.c. It looks like it will read data from the write buffer, or from the read buffer, whichever it finds first. Isn't that a little bit strange? Perhaps someone can explain how this implementation works. Without a setup to single-step through this logic, it's hard to continue analyzing by reading code. Perhaps you could share more details about your setup (and the defconfig produced by 'make savedefconfig')? Cheers, Nathan
