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Message-ID: <20160604081534.GA22055@colbert.idosch.org> Date: Sat, 4 Jun 2016 11:15:34 +0300 From: Ido Schimmel <idosch@...lanox.com> To: Shmulik Ladkani <shmulik.ladkani@...il.com> CC: <stephen@...workplumber.org>, <davem@...emloft.net>, <bridge@...ts.linux-foundation.org>, <netdev@...r.kernel.org>, <eladr@...lanox.com>, <ogerlitz@...lanox.com>, <jiri@...lanox.com>, <yotamg@...lanox.com>, <nogahf@...lanox.com>, Florian Westphal <fw@...len.de> Subject: Re: [PATCH net] bridge: Fix incorrect re-injection of STP packets Sat, Jun 04, 2016 at 09:41:41AM IDT, shmulik.ladkani@...il.com wrote: >Hi, > >On Fri, 3 Jun 2016 12:39:45 +0300 Ido Schimmel <idosch@...lanox.com> wrote: >> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c >> index 1607977..c73ed44 100644 >> --- a/net/bridge/br_input.c >> +++ b/net/bridge/br_input.c >> @@ -223,9 +223,7 @@ static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_bu >> if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid)) >> br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false); >> >> - BR_INPUT_SKB_CB(skb)->brdev = p->br->dev; >> - br_pass_frame_up(skb); >> - return 0; >> + return RX_HANDLER_PASS; >> } >> >> /* >> @@ -238,6 +236,7 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb) >> struct sk_buff *skb = *pskb; >> const unsigned char *dest = eth_hdr(skb)->h_dest; >> br_should_route_hook_t *rhook; >> + int err; >> >> if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) >> return RX_HANDLER_PASS; >> @@ -287,8 +286,11 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb) >> } >> >> /* Deliver packet to local host only */ >> - NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev), >> - NULL, skb, skb->dev, NULL, br_handle_local_finish); >> + err = NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev), >> + NULL, skb, skb->dev, NULL, >> + br_handle_local_finish); >> + if (err == RX_HANDLER_PASS) >> + return RX_HANDLER_PASS; >> return RX_HANDLER_CONSUMED; > >Seems '*pskb = skb' is needed prior returning RX_HANDLER_PASS - there's >a 'skb = skb_share_check()' at beginning of br_handle_frame. > >(The *pskb = skb was present prior 8626c56c8279, but gone since there >was no longer an RX_HANDLER_PASS return). Right! Will fix that in v2. > >One nit to consider: > >The fix relies on the fact that RX_HANDLER_PASS != 0 (otherwise we end up >not knowing whether skb was STOLEN or br_handle_local_finish has >executed, which was the original problem 8626c56c8279 tried to address). > >No reason to use the RX_HANDLER_xxx enumeration space as the ret code >of an 'okfn' (br_handle_local_finish in this case). >Some positive value locally defined in br_input.c (and documented in >br_handle_local_finish) would do. Yes, I agree it would be clearer to state that explicitly. Will add that in v2. Thanks for reviewing!
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