Re: [RFC PATCH bpf-next 2/3] bpf: Add helper to do forwarding lookups in kernel FDB table
From: David Ahern <hidden>
Date: 2020-07-31 17:15:25
Also in:
bpf, bridge
On 7/30/20 10:44 PM, Yoshiki Komachi wrote:
quoted hunk ↗ jump to hunk
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@@ -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;
I need to look at the details more closely, but on first reading 2 things caught me eye: 1. you need to make sure flags is 0 since there are no supported flags at the moment, and
+ + 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; + + 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);
2. this needs to be done via netdev ops to avoid referencing bridge code which can be compiled as a module. I suspect the build robots will id this part soon.