All of lore.kernel.org
 help / color / mirror / Atom feed
From: David Ahern <dsahern@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: netdev@vger.kernel.org, borkmann@iogearbox.net, ast@kernel.org,
	davem@davemloft.net, shm@cumulusnetworks.com,
	roopa@cumulusnetworks.com, toke@toke.dk,
	john.fastabend@gmail.com, Tariq Toukan <tariqt@mellanox.com>
Subject: Re: [RFC v2 bpf-next 9/9] samples/bpf: Add examples of ipv4 and ipv6 forwarding in XDP
Date: Wed, 2 May 2018 09:40:08 -0600	[thread overview]
Message-ID: <73d3a185-2ac2-6f40-1708-f9dd6f0be4e8@gmail.com> (raw)
In-Reply-To: <20180502131306.07c3acee@redhat.com>

On 5/2/18 5:13 AM, Jesper Dangaard Brouer wrote:
> 
> On Sun, 29 Apr 2018 11:07:52 -0700 David Ahern <dsahern@gmail.com> wrote:
> 
>> +	/* verify egress index has xdp support */
>> +	// TO-DO bpf_map_lookup_elem(&tx_port, &key) fails with
>> +	//       cannot pass map_type 14 into func bpf_map_lookup_elem#1:
> 
> I just want to point out that I/we are aware of this "usability"
> problem with the sample program, but I don't want to block the FIB
> helper going upstream, we can fix this problem later.
> 
> The problem is that if you load this bpf/xdp prog, then all incoming
> traffic (on that interface), will be forward using XDP, regardless
> whether the egress ifindex support XDP or not.  And if not supported,
> then packets are dropped hard (only detectable via tracepoints).
> 
> If the bpf prog could tell/know that the egress ifindex doesn't
> support XDP xmit, then it could simply return XDP_PASS to fallback to
> the normal network stack.
> 

That's what the above lookup is intending but DEVMAP type does not
handle lookups from xdp programs. Any chance of fixing that?

  reply	other threads:[~2018-05-02 15:40 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-29 18:07 [RFC v2 bpf-next 0/9] bpf: Add helper to do FIB lookups David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 1/9] net/ipv6: Rename fib6_lookup to fib6_node_lookup David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 2/9] net/ipv6: Rename rt6_multipath_select David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 3/9] net/ipv6: Extract table lookup from ip6_pol_route David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 4/9] net/ipv6: Refactor fib6_rule_action David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 5/9] net/ipv6: Add fib6_lookup David Ahern
2018-05-01 18:15   ` Vincent Bernat
2018-05-01 18:25     ` David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 6/9] net/ipv6: Update fib6 tracepoint to take fib6_info David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 7/9] net/ipv6: Add fib lookup stubs for use in bpf helper David Ahern
2018-04-29 18:07 ` [RFC v2 bpf-next 8/9] bpf: Provide helper to do lookups in kernel FIB table David Ahern
2018-04-29 23:36   ` Alexei Starovoitov
2018-04-30  1:13     ` David Ahern
2018-05-15  3:46       ` David Ahern
2018-05-02 11:27   ` Jesper Dangaard Brouer
2018-05-02 15:37     ` David Ahern
2018-05-02 17:00       ` David Miller
2018-04-29 18:07 ` [RFC v2 bpf-next 9/9] samples/bpf: Add examples of ipv4 and ipv6 forwarding in XDP David Ahern
2018-05-02 11:13   ` Jesper Dangaard Brouer
2018-05-02 15:40     ` David Ahern [this message]
2018-05-01 14:20 ` [RFC v2 bpf-next 0/9] bpf: Add helper to do FIB lookups David Miller

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=73d3a185-2ac2-6f40-1708-f9dd6f0be4e8@gmail.com \
    --to=dsahern@gmail.com \
    --cc=ast@kernel.org \
    --cc=borkmann@iogearbox.net \
    --cc=brouer@redhat.com \
    --cc=davem@davemloft.net \
    --cc=john.fastabend@gmail.com \
    --cc=netdev@vger.kernel.org \
    --cc=roopa@cumulusnetworks.com \
    --cc=shm@cumulusnetworks.com \
    --cc=tariqt@mellanox.com \
    --cc=toke@toke.dk \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.