/* * Forwarding decision * Linux ethernet bridge * * Authors: * Lennert Buytenhek <buytenh@gnu.org> * * $Id: br_forward.c,v 1.4 2001/08/14 22:05:57 davem Exp $ * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/kernel.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <linux/if_vlan.h> #include <linux/netfilter_bridge.h> #include "br_private.h" /* Don't forward packets to originating port or forwarding diasabled */ static inline int should_deliver(const struct net_bridge_port *p, const struct sk_buff *skb) { return (skb->dev != p->dev && p->state == BR_STATE_FORWARDING); } static inline unsigned packet_length(const struct sk_buff *skb) { return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0); } int br_dev_queue_push_xmit(struct sk_buff *skb) { /* drop mtu oversized packets except gso */ if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb)) kfree_skb(skb); else { /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */ if (nf_bridge_maybe_copy_header(skb)) kfree_skb(skb); else { skb_push(skb, ETH_HLEN); dev_queue_xmit(skb); } } return 0; } int br_forward_finish(struct sk_buff *skb) { return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev, br_dev_queue_push_xmit); } static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) { skb->dev = to->dev; NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, br_forward_finish); } static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb) { struct net_device *indev; indev = skb->dev; skb->dev = to->dev; skb_forward_csum(skb); NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev, br_forward_finish); } /* called with rcu_read_lock */ void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) { if (should_deliver(to, skb)) { __br_deliver(to, skb); return; } kfree_skb(skb); } /* called with rcu_read_lock */ void br_forward(const struct net_bridge_port *to, struct sk_buff *skb) { if (should_deliver(to, skb)) { __br_forward(to, skb); return; } kfree_skb(skb); } /* called under bridge lock */ static void br_flood(struct net_bridge *br, struct sk_buff *skb, void (*__packet_hook)(const struct net_bridge_port *p, struct sk_buff *skb)) { struct net_bridge_port *p; struct net_bridge_port *prev; prev = NULL; list_for_each_entry_rcu(p, &br->port_list, list) { if (should_deliver(p, skb)) { if (prev != NULL) { struct sk_buff *skb2; if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) { br->statistics.tx_dropped++; kfree_skb(skb); return; } __packet_hook(prev, skb2); } prev = p; } } if (prev != NULL) { __packet_hook(prev, skb); return; } kfree_skb(skb); } /* called with rcu_read_lock */ void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb) { br_flood(br, skb, __br_deliver); } /* called under bridge lock */ void br_flood_forward(struct net_bridge *br, struct sk_buff *skb) { br_flood(br, skb, __br_forward); }