Re: [PATCH net] bridge: Fix incorrect re-injection of STP packets
From: Shmulik Ladkani <hidden>
Date: 2016-06-04 06:41:56
Also in:
bridge
Hi, On Fri, 3 Jun 2016 12:39:45 +0300 Ido Schimmel [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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). 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. Regards, Shmulik