On 10/30/20 10:50 AM, Jesper Dangaard Brouer wrote: > The BPF-helpers for FIB lookup (bpf_xdp_fib_lookup and bpf_skb_fib_lookup) > can perform MTU check and return BPF_FIB_LKUP_RET_FRAG_NEEDED. The BPF-prog > don't know the MTU value that caused this rejection. > > If the BPF-prog wants to implement PMTU (Path MTU Discovery) (rfc1191) it > need to know this MTU value for the ICMP packet. > > Patch change lookup and result struct bpf_fib_lookup, to contain this MTU > value as output via a union with 'tot_len' as this is the value used for > the MTU lookup. > > V5: > - Fixed uninit value spotted by Dan Carpenter. > - Name struct output member mtu_result > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> > --- > include/uapi/linux/bpf.h | 11 +++++++++-- > net/core/filter.c | 22 +++++++++++++++------- > tools/include/uapi/linux/bpf.h | 11 +++++++++-- > 3 files changed, 33 insertions(+), 11 deletions(-) > Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
