From: Jakub Kicinski <kuba@kernel.org>
To: Taehee Yoo <ap420073@gmail.com>
Cc: davem@davemloft.net, pabeni@redhat.com, edumazet@google.com,
netdev@vger.kernel.org
Subject: Re: [PATCH net v2 2/2] amt: do not skip remaining handling of advertisement message
Date: Tue, 17 May 2022 15:24:09 -0700 [thread overview]
Message-ID: <20220517152409.5545f6e8@kernel.org> (raw)
In-Reply-To: <20220517070527.10591-3-ap420073@gmail.com>
On Tue, 17 May 2022 07:05:27 +0000 Taehee Yoo wrote:
> When a gateway receives an advertisement message, it extracts relay
> information and then it should be deleted.
> But the advertisement handler doesn't do that.
> So, after amt_advertisement_handler(), that message should not be skipped
> remaining handling.
>
> Fixes: cbc21dc1cfe9 ("amt: add data plane of amt interface")
> Signed-off-by: Taehee Yoo <ap420073@gmail.com>
> diff --git a/drivers/net/amt.c b/drivers/net/amt.c
> index 2b4ce3869f08..6ce2ecd07640 100644
> --- a/drivers/net/amt.c
> +++ b/drivers/net/amt.c
> @@ -2698,9 +2698,10 @@ static int amt_rcv(struct sock *sk, struct sk_buff *skb)
> err = true;
> goto drop;
> }
> - if (amt_advertisement_handler(amt, skb))
> + err = amt_advertisement_handler(amt, skb);
> + if (err)
> amt->dev->stats.rx_dropped++;
> - goto out;
> + break;
> case AMT_MSG_MULTICAST_DATA:
> if (iph->saddr != amt->remote_ip) {
> netdev_dbg(amt->dev, "Invalid Relay IP\n");
I guess I'll have to spell it out for you more cause either you didn't
understand me or I don't understand your reply on v1. Here's the full
function:
2669 static int amt_rcv(struct sock *sk, struct sk_buff *skb)
2670 {
2671 struct amt_dev *amt;
2672 struct iphdr *iph;
2673 int type;
2674 bool err;
2675
2676 rcu_read_lock_bh();
2677 amt = rcu_dereference_sk_user_data(sk);
2678 if (!amt) {
2679 err = true;
2680 goto out;
2681 }
2682
2683 skb->dev = amt->dev;
2684 iph = ip_hdr(skb);
2685 type = amt_parse_type(skb);
2686 if (type == -1) {
2687 err = true;
2688 goto drop;
2689 }
2690
2691 if (amt->mode == AMT_MODE_GATEWAY) {
2692 switch (type) {
2693 case AMT_MSG_ADVERTISEMENT:
2694 if (iph->saddr != amt->discovery_ip) {
2695 netdev_dbg(amt->dev, "Invalid Relay IP\n");
2696 err = true;
2697 goto drop;
2698 }
2699 if (amt_advertisement_handler(amt, skb))
2700 amt->dev->stats.rx_dropped++;
2701 goto out;
2702 case AMT_MSG_MULTICAST_DATA:
2703 if (iph->saddr != amt->remote_ip) {
2704 netdev_dbg(amt->dev, "Invalid Relay IP\n");
2705 err = true;
2706 goto drop;
2707 }
2708 err = amt_multicast_data_handler(amt, skb);
2709 if (err)
2710 goto drop;
2711 else
2712 goto out;
2713 case AMT_MSG_MEMBERSHIP_QUERY:
2714 if (iph->saddr != amt->remote_ip) {
2715 netdev_dbg(amt->dev, "Invalid Relay IP\n");
2716 err = true;
2717 goto drop;
2718 }
2719 err = amt_membership_query_handler(amt, skb);
2720 if (err)
2721 goto drop;
2722 else
2723 goto out;
2724 default:
2725 err = true;
2726 netdev_dbg(amt->dev, "Invalid type of Gateway\n");
2727 break;
2728 }
2729 } else {
2730 switch (type) {
2731 case AMT_MSG_DISCOVERY:
2732 err = amt_discovery_handler(amt, skb);
2733 break;
2734 case AMT_MSG_REQUEST:
2735 err = amt_request_handler(amt, skb);
2736 break;
2737 case AMT_MSG_MEMBERSHIP_UPDATE:
2738 err = amt_update_handler(amt, skb);
2739 if (err)
2740 goto drop;
2741 else
2742 goto out;
2743 default:
2744 err = true;
2745 netdev_dbg(amt->dev, "Invalid type of relay\n");
2746 break;
2747 }
2748 }
2749 drop:
2750 if (err) {
2751 amt->dev->stats.rx_dropped++;
2752 kfree_skb(skb);
2753 } else {
2754 consume_skb(skb);
2755 }
2756 out:
2757 rcu_read_unlock_bh();
2758 return 0;
2759 }
You're changing line 2699, we used to bump the rx_dropped on line 2700
and then the goto on line 2701 takes us to line 2756 - unlock, return.
Now since you have replaced the goto on line 2701 with a "break" the
code will go from line 2701 to line 2749/2750. If err is set we'll
increase rx_dropped again on line 2751.
In other words rx_dropped will be increased both on line 2700 and
line 2751.
What am I missing?
Also I don't quite understand your commit message. The only thing we
used to skip is the freeing of the skb. Or do you mean we need to
return an error from amt_rcv() ?
next prev parent reply other threads:[~2022-05-17 22:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-17 7:05 [PATCH net v2 0/2] amt: fix several bugs in gateway mode Taehee Yoo
2022-05-17 7:05 ` [PATCH net v2 1/2] amt: fix gateway mode stuck Taehee Yoo
2022-05-17 7:05 ` [PATCH net v2 2/2] amt: do not skip remaining handling of advertisement message Taehee Yoo
2022-05-17 22:24 ` Jakub Kicinski [this message]
2022-05-18 0:21 ` Taehee Yoo
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