From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: daniel@iogearbox.net, netdev@vger.kernel.org,
bpf@vger.kernel.org, sdf@google.com
Subject: Re: [PATCH bpf-next v5 1/2] bpf: setup socket family and addresses in bpf_prog_test_run_skb
Date: Sun, 2 Aug 2020 15:48:50 -0700 [thread overview]
Message-ID: <20200802224850.ezn6tmcz4657ia4z@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200802213631.78937-2-zeil@yandex-team.ru>
On Mon, Aug 03, 2020 at 12:36:30AM +0300, Dmitry Yakunin wrote:
> Now it's impossible to test all branches of cgroup_skb bpf program which
> accesses skb->family and skb->{local,remote}_ip{4,6} fields because they
> are zeroed during socket allocation. This commit fills socket family and
> addresses from related fields in constructed skb.
>
> v2:
> - fix build without CONFIG_IPV6 (kernel test robot <lkp@intel.com>)
>
> v3:
> - check skb length before access to inet headers (Eric Dumazet)
>
> Signed-off-by: Dmitry Yakunin <zeil@yandex-team.ru>
> ---
> net/bpf/test_run.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index b03c469..8d69295 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -449,6 +449,27 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
> skb->protocol = eth_type_trans(skb, current->nsproxy->net_ns->loopback_dev);
> skb_reset_network_header(skb);
>
> + switch (skb->protocol) {
> + case htons(ETH_P_IP):
> + sk->sk_family = AF_INET;
> + if (pskb_may_pull(skb, sizeof(struct iphdr))) {
skb was just inited with __skb_put(skb, size);
Looking at pskb_may_pull() messes with my brain too much,
since it should never go into __pskb_pull_tail path.
Can you open code the skb->len check instead?
if (sizeof(struct iphdr) <= skb_headlen(skb)) {
> + sk->sk_rcv_saddr = ip_hdr(skb)->saddr;
> + sk->sk_daddr = ip_hdr(skb)->daddr;
> + }
> + break;
> +#if IS_ENABLED(CONFIG_IPV6)
> + case htons(ETH_P_IPV6):
> + sk->sk_family = AF_INET6;
> + if (pskb_may_pull(skb, sizeof(struct ipv6hdr))) {
> + sk->sk_v6_rcv_saddr = ipv6_hdr(skb)->saddr;
> + sk->sk_v6_daddr = ipv6_hdr(skb)->daddr;
> + }
> + break;
> +#endif
> + default:
> + break;
> + }
> +
> if (is_l2)
> __skb_push(skb, hh_len);
> if (is_direct_pkt_access)
> --
> 2.7.4
>
next prev parent reply other threads:[~2020-08-02 22:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-02 21:36 [PATCH bpf-next v5 0/2] bpf: cgroup skb improvements for bpf_prog_test_run Dmitry Yakunin
2020-08-02 21:36 ` [PATCH bpf-next v5 1/2] bpf: setup socket family and addresses in bpf_prog_test_run_skb Dmitry Yakunin
2020-08-02 22:48 ` Alexei Starovoitov [this message]
2020-08-02 21:36 ` [PATCH bpf-next v5 2/2] bpf: allow to specify ifindex for skb " Dmitry Yakunin
-- strict thread matches above, loose matches on Subject: below --
2020-08-02 21:30 [PATCH bpf-next v4 0/2] bpf: cgroup skb improvements for bpf_prog_test_run Dmitry Yakunin
2020-08-02 21:30 ` [PATCH bpf-next v5 1/2] bpf: setup socket family and addresses in bpf_prog_test_run_skb Dmitry Yakunin
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