[Bridge] SPT functions

[Gustavo Martin]

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Hello,

     First, sorry for my english. I have to get better it.
     I am trying to develop a new protocol for the linux kernel 2.6.26
similar to RSTP by my free time. Because of it I am searching the bridging
code. I began from the function netif_receive_skb (I don't need to know
anything about the hardware or the interruptions) looking for the first
functions connected with the spanning tree protocol implementation.
     I found this:

1- The function netif_receive_skb calls to:  skb = handle_bridge(skb,
&pt_prev, &ret, orig_dev)
2- In handle_bridge(skb, &pt_prev, &ret, orig_dev) I found: return
br_handle_frame_hook(port, skb)
3- In br_handle_frame I found:  if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb,
skb->dev, NULL, br_handle_local_finish))
4- In br_handle_local_finish I didn't find anything.

     I have been reading the book "Understanding Linux Network Internals
(2005)" but this book (I think) is for the kernel 2.6.16. In this book the
author speaks about the function br_stp_handle_bpdu. With the kernel 2.6.26
in spite of that function you can find br_handle_local_finish.

     I continued searching in netif_receive_skb. In this function after the
call to handle_bridge I found this code:

2016       skb = handle_bridge(skb, &pt_prev, &ret, orig_dev);
2107        if (!skb)
2108                goto out;
2109        skb = handle_macvlan(skb, &pt_prev, &ret, orig_dev);
2110        if (!skb)
2111                goto out;
2112
2113        type = skb->protocol;
2114        list_for_each_entry_rcu(ptype,
2115                        &ptype_base[ntohs(type) &
PTYPE_HASH_MASK], list) {
2116                if (ptype->type == type &&
2117                    (!ptype->dev || ptype->dev == skb->dev)) {
2118                        if (pt_prev)
2119                                ret = deliver_skb(skb, pt_prev,
orig_dev);
2120                        pt_prev = ptype;
2121                }
2122        }
2123
2124        if (pt_prev) {
2125                ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
2126        } else {
2127                kfree_skb(skb);
2128                /* Jamal, now you will not able to escape explaining
2129                 * me how you were going to use this. :-)
2130                 */
2131                ret = NET_RX_DROP;
2132        }


     My question (probably stupid question, sorry but this is my first time
with the linux kernel) is:  Where connect the SPANING TREE PROTOCOL
functions with the bridging code?


     Thanks in advance.

- --
Gustavo Martín Morcuende
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