> 2020/07/31 20:52、Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>のメール:
>
> On Fri, Jul 31, 2020 at 01:44:19PM +0900, Yoshiki Komachi wrote:
>> This patch adds a new bpf helper to access FDB in the kernel tables
>> from XDP programs. The helper enables us to find the destination port
>> of master bridge in XDP layer with high speed. If an entry in the
>> tables is successfully found, egress device index will be returned.
>>
>> In cases of failure, packets will be dropped or forwarded to upper
>> networking stack in the kernel by XDP programs. Multicast and broadcast
>> packets are currently not supported. Thus, these will need to be
>> passed to upper layer on the basis of XDP_PASS action.
>>
>> The API uses destination MAC and VLAN ID as keys, so XDP programs
>> need to extract these from forwarded packets.
>>
>> Signed-off-by: Yoshiki Komachi <komachi.yoshiki@xxxxxxxxx>
>> ---
>> include/uapi/linux/bpf.h | 28 +++++++++++++++++++++
>> net/core/filter.c | 45 ++++++++++++++++++++++++++++++++++
>> scripts/bpf_helpers_doc.py | 1 +
>> tools/include/uapi/linux/bpf.h | 28 +++++++++++++++++++++
>> 4 files changed, 102 insertions(+)
>>
>
> [...]
>
>> diff --git a/net/core/filter.c b/net/core/filter.c
>> index 654c346b7d91..68800d1b8cd5 100644
>> --- a/net/core/filter.c
>> +++ b/net/core/filter.c
>> @@ -45,6 +45,7 @@
>> #include <linux/filter.h>
>> #include <linux/ratelimit.h>
>> #include <linux/seccomp.h>
>> +#include <linux/if_bridge.h>
>> #include <linux/if_vlan.h>
>> #include <linux/bpf.h>
>> #include <linux/btf.h>
>> @@ -5084,6 +5085,46 @@ static const struct bpf_func_proto bpf_skb_fib_lookup_proto = {
>> .arg4_type = ARG_ANYTHING,
>> };
>>
>> +#if IS_ENABLED(CONFIG_BRIDGE)
>> +BPF_CALL_4(bpf_xdp_fdb_lookup, struct xdp_buff *, ctx,
>> + struct bpf_fdb_lookup *, params, int, plen, u32, flags)
>> +{
>> + struct net_device *src, *dst;
>> + struct net *net;
>> +
>> + if (plen < sizeof(*params))
>> + return -EINVAL;
>> +
>> + net = dev_net(ctx->rxq->dev);
>> +
>> + if (is_multicast_ether_addr(params->addr) ||
>> + is_broadcast_ether_addr(params->addr))
>> + return BPF_FDB_LKUP_RET_NOENT;
>
> small nit: you could move that validation before dev_net() call.
Thanks for your quick response.
I will try to fix it in the next version.
Best regards,
>> +
>> + src = dev_get_by_index_rcu(net, params->ifindex);
>> + if (unlikely(!src))
>> + return -ENODEV;
>> +
>> + dst = br_fdb_find_port_xdp(src, params->addr, params->vlan_id);
>> + if (dst) {
>> + params->ifindex = dst->ifindex;
>> + return BPF_FDB_LKUP_RET_SUCCESS;
>> + }
>> +
>> + return BPF_FDB_LKUP_RET_NOENT;
>> +}
—
Yoshiki Komachi
komachi.yoshiki@xxxxxxxxx
