From: Daniel Borkmann <daniel@iogearbox.net>
To: Yoshiki Komachi <komachi.yoshiki@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Kicinski <kuba@kernel.org>, Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
Andrii Nakryiko <andriin@fb.com>, KP Singh <kpsingh@chromium.org>,
Roopa Prabhu <roopa@cumulusnetworks.com>,
Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
David Ahern <dsahern@kernel.org>
Cc: netdev@vger.kernel.org, bridge@lists.linux-foundation.org,
bpf@vger.kernel.org
Subject: Re: [RFC PATCH bpf-next 2/3] bpf: Add helper to do forwarding lookups in kernel FDB table
Date: Fri, 31 Jul 2020 23:12:27 +0200 [thread overview]
Message-ID: <9420fbc2-3139-f23e-fb6b-e3d28b9bee5f@iogearbox.net> (raw)
In-Reply-To: <1596170660-5582-3-git-send-email-komachi.yoshiki@gmail.com>
On 7/31/20 6:44 AM, 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@gmail.com>
Few initial comments below:
> ---
> 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/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 54d0c886e3ba..f2e729dd1721 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -2149,6 +2149,22 @@ union bpf_attr {
> * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
> * packet is not forwarded or needs assist from full stack
> *
> + * long bpf_fdb_lookup(void *ctx, struct bpf_fdb_lookup *params, int plen, u32 flags)
> + * Description
> + * Do FDB lookup in kernel tables using parameters in *params*.
> + * If lookup is successful (ie., FDB lookup finds a destination entry),
> + * ifindex is set to the egress device index from the FDB lookup.
> + * Both multicast and broadcast packets are currently unsupported
> + * in XDP layer.
> + *
> + * *plen* argument is the size of the passed **struct bpf_fdb_lookup**.
> + * *ctx* is only **struct xdp_md** for XDP programs.
> + *
> + * Return
> + * * < 0 if any input argument is invalid
> + * * 0 on success (destination port is found)
> + * * > 0 on failure (there is no entry)
> + *
> * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
> * Description
> * Add an entry to, or update a sockhash *map* referencing sockets.
> @@ -3449,6 +3465,7 @@ union bpf_attr {
> FN(get_stack), \
> FN(skb_load_bytes_relative), \
> FN(fib_lookup), \
> + FN(fdb_lookup), \
This breaks UAPI. Needs to be added to the very end of the list.
> FN(sock_hash_update), \
> FN(msg_redirect_hash), \
> FN(sk_redirect_hash), \
> @@ -4328,6 +4345,17 @@ struct bpf_fib_lookup {
> __u8 dmac[6]; /* ETH_ALEN */
> };
>
> +enum {
> + BPF_FDB_LKUP_RET_SUCCESS, /* lookup successful */
> + BPF_FDB_LKUP_RET_NOENT, /* entry is not found */
> +};
> +
> +struct bpf_fdb_lookup {
> + unsigned char addr[6]; /* ETH_ALEN */
> + __u16 vlan_id;
> + __u32 ifindex;
> +};
> +
> enum bpf_task_fd_type {
> BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
> BPF_FD_TYPE_TRACEPOINT, /* tp name */
> 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;
Given flags are not used, this needs to reject anything invalid otherwise
you're not able to extend it in future.
> + 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);
> + if (dst) {
> + params->ifindex = dst->ifindex;
> + return BPF_FDB_LKUP_RET_SUCCESS;
> + }
Currently the helper description says nothing that this is /only/ limited to
bridges. I think it would be better to also name the helper bpf_br_fdb_lookup()
as well if so to avoid any confusion.
> + return BPF_FDB_LKUP_RET_NOENT;
> +}
> +
> +static const struct bpf_func_proto bpf_xdp_fdb_lookup_proto = {
> + .func = bpf_xdp_fdb_lookup,
> + .gpl_only = true,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_CTX,
> + .arg2_type = ARG_PTR_TO_MEM,
> + .arg3_type = ARG_CONST_SIZE,
> + .arg4_type = ARG_ANYTHING,
> +};
> +#endif
This should also have a tc pendant (similar as done in routing lookup helper)
in case native XDP is not available. This will be useful for those that have
the same code compilable for both tc/XDP.
> #if IS_ENABLED(CONFIG_IPV6_SEG6_BPF)
> static int bpf_push_seg6_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
> {
> @@ -6477,6 +6518,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_xdp_adjust_tail_proto;
> case BPF_FUNC_fib_lookup:
> return &bpf_xdp_fib_lookup_proto;
> +#if IS_ENABLED(CONFIG_BRIDGE)
> + case BPF_FUNC_fdb_lookup:
> + return &bpf_xdp_fdb_lookup_proto;
> +#endif
> #ifdef CONFIG_INET
> case BPF_FUNC_sk_lookup_udp:
> return &bpf_xdp_sk_lookup_udp_proto;
next prev parent reply other threads:[~2020-07-31 21:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 4:44 [RFC PATCH bpf-next 0/3] Add a new bpf helper for FDB lookup Yoshiki Komachi
2020-07-31 4:44 ` [RFC PATCH bpf-next 1/3] net/bridge: Add new function to access FDB from XDP programs Yoshiki Komachi
2020-07-31 4:44 ` [RFC PATCH bpf-next 2/3] bpf: Add helper to do forwarding lookups in kernel FDB table Yoshiki Komachi
2020-07-31 11:52 ` Maciej Fijalkowski
2020-08-04 8:44 ` Yoshiki Komachi
2020-07-31 17:15 ` David Ahern
2020-08-04 11:27 ` Yoshiki Komachi
2020-08-05 16:38 ` David Ahern
2020-08-07 8:06 ` Yoshiki Komachi
2020-07-31 21:12 ` Daniel Borkmann [this message]
2020-08-05 4:45 ` Yoshiki Komachi
2020-07-31 4:44 ` [RFC PATCH bpf-next 3/3] samples/bpf: Add a simple bridge example accelerated with XDP Yoshiki Komachi
2020-07-31 14:15 ` Jesper Dangaard Brouer
2020-08-04 10:08 ` Yoshiki Komachi
2020-07-31 17:48 ` Andrii Nakryiko
2020-08-04 10:35 ` Yoshiki Komachi
2020-07-31 21:52 ` [RFC PATCH bpf-next 0/3] Add a new bpf helper for FDB lookup John Fastabend
2020-08-05 10:26 ` Yoshiki Komachi
2020-08-05 16:36 ` David Ahern
2020-08-07 8:30 ` Yoshiki Komachi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9420fbc2-3139-f23e-fb6b-e3d28b9bee5f@iogearbox.net \
--to=daniel@iogearbox.net \
--cc=andriin@fb.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=bridge@lists.linux-foundation.org \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=hawk@kernel.org \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=komachi.yoshiki@gmail.com \
--cc=kpsingh@chromium.org \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=nikolay@cumulusnetworks.com \
--cc=roopa@cumulusnetworks.com \
--cc=songliubraving@fb.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).