On Mon, Dec 4, 2017 at 6:39 AM, Anmol Panda <anmol07.visitor@xxxxxxxxxxxxxx> wrote: > Hello All, > We are trying to implement L2 forwarding in xdp and we need to convert > the mac-address to a hash value. Thus far, we have tried using crc32 > functions from <linux/crc32.h> for kernel space but it can't be used in user > space. We need a common crc hash function for both kernel and user space. > > The kernel crc function causes the following error: > > invalid relo for insn[24].code 0x85 > bpf_load_program() err=22 > 0: (61) r2 = *(u32 *)(r1 +4) > 1: (61) r1 = *(u32 *)(r1 +0) > . > . > . > 23: (b7) r3 = 6 > 24: (85) call unknown#-1 > BPF_CALL uses reserved fields The kernel crc function eventually calls crc32_le_shift or other variants in lib/crc32.c. BPF program is able to resolve the reference to crc32_le_shift at verification time, hence you will see the failure above. You may need to implement one or re-structure an existing implementation (e.g. the one from linux) into separate header files, so you can include in both bpf program and your user space application. > > > Can you please point to some examples or references? > We would be highly grateful. > > Thanks, > Sincerely, >
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