netdev - Re: [RFC bpf-next 7/7] selftests/bpf: extend xdp_hw

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 13 Jun 2023 12:00:38 -0700
From: Stanislav Fomichev <sdf@...gle.com>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc: bpf@...r.kernel.org, ast@...nel.org, daniel@...earbox.net, 
	andrii@...nel.org, martin.lau@...ux.dev, song@...nel.org, yhs@...com, 
	john.fastabend@...il.com, kpsingh@...nel.org, haoluo@...gle.com, 
	jolsa@...nel.org, netdev@...r.kernel.org
Subject: Re: [RFC bpf-next 7/7] selftests/bpf: extend xdp_hw_metadata with
 devtx kfuncs

On Tue, Jun 13, 2023 at 8:03 AM Willem de Bruijn
<willemdebruijn.kernel@...il.com> wrote:
>
> On Mon, Jun 12, 2023 at 7:26 PM Stanislav Fomichev <sdf@...gle.com> wrote:
> >
> > When we get packets on port 9091, we swap src/dst and send it out.
> > At this point, we also request the timestamp and plumb it back
> > to the userspace. The userspace simply prints the timestamp.
> >
> > Haven't really tested, still working on mlx5 patches...
> >
> > Cc: netdev@...r.kernel.org
> > Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
>
>
> > +++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> > @@ -10,7 +10,8 @@
> >   *   - rx_hash
> >   *
> >   * TX:
> > - * - TBD
> > + * - UDP 9091 packets trigger TX reply
>
> This branch on port is missing?

That's the ping_pong part. Evey packet arriving on 9091 port gets
received by af_xdp and is sent back.

> > +static void ping_pong(struct xsk *xsk, void *rx_packet)
> > +{
> > +       struct ipv6hdr *ip6h = NULL;
> > +       struct iphdr *iph = NULL;
> > +       struct xdp_desc *tx_desc;
> > +       struct udphdr *udph;
> > +       struct ethhdr *eth;
> > +       void *data;
> > +       __u32 idx;
> > +       int ret;
> > +       int len;
> > +
> > +       ret = xsk_ring_prod__reserve(&xsk->tx, 1, &idx);
> > +       if (ret != 1) {
> > +               printf("%p: failed to reserve tx slot\n", xsk);
> > +               return;
> > +       }
> > +
> > +       tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx);
> > +       tx_desc->addr = idx % (UMEM_NUM / 2) * UMEM_FRAME_SIZE;
> > +       data = xsk_umem__get_data(xsk->umem_area, tx_desc->addr);
> > +
> > +       eth = data;
> > +
> > +       if (eth->h_proto == htons(ETH_P_IP)) {
> > +               iph = (void *)(eth + 1);
> > +               udph = (void *)(iph + 1);
> > +       } else if (eth->h_proto == htons(ETH_P_IPV6)) {
> > +               ip6h = (void *)(eth + 1);
> > +               udph = (void *)(ip6h + 1);
> > +       } else {
> > +               xsk_ring_prod__cancel(&xsk->tx, 1);
> > +               return;
> > +       }
> > +
> > +       len = ETH_HLEN;
> > +       if (ip6h)
> > +               len += ntohs(ip6h->payload_len);
>
> sizeof(*ip6h) + ntohs(ip6h->payload_len) ?

Ooop, thanks, that's clearly not tested :-)

> > +       if (iph)
> > +               len += ntohs(iph->tot_len);
> > +
> > +       memcpy(data, rx_packet, len);
> > +       swap(eth->h_dest, eth->h_source, ETH_ALEN);
> > +       if (iph)
> > +               swap(&iph->saddr, &iph->daddr, 4);
>
> need to recompute ipv4 checksum?

Discussed offline: swapping the aligned-u16 chunks preserves the checksum.