diff options
Diffstat (limited to 'net/bridge/br_forward.c')
| -rw-r--r-- | net/bridge/br_forward.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c new file mode 100644 index 00000000..a2098e3d --- /dev/null +++ b/net/bridge/br_forward.c @@ -0,0 +1,272 @@ +/* + * Forwarding decision + * Linux ethernet bridge + * + * Authors: + * Lennert Buytenhek <buytenh@gnu.org> + * + * 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/err.h> +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/netdevice.h> +#include <linux/netpoll.h> +#include <linux/skbuff.h> +#include <linux/if_vlan.h> +#include <linux/netfilter_bridge.h> +#include "br_private.h" + +static int deliver_clone(const struct net_bridge_port *prev, + struct sk_buff *skb, + void (*__packet_hook)(const struct net_bridge_port *p, + struct sk_buff *skb)); + +/* 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 (((p->flags & BR_HAIRPIN_MODE) || 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) +{ + /* ip_fragment doesn't copy the MAC header */ + if (nf_bridge_maybe_copy_header(skb) || + (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) { + kfree_skb(skb); + } else { + skb_push(skb, ETH_HLEN); + br_drop_fake_rtable(skb); + dev_queue_xmit(skb); + } + + return 0; +} + +int br_forward_finish(struct sk_buff *skb) +{ + return NF_HOOK(NFPROTO_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; + + if (unlikely(netpoll_tx_running(to->dev))) { + if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb)) + kfree_skb(skb); + else { + skb_push(skb, ETH_HLEN); + br_netpoll_send_skb(to, skb); + } + return; + } + + NF_HOOK(NFPROTO_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; + + if (skb_warn_if_lro(skb)) { + kfree_skb(skb); + return; + } + + indev = skb->dev; + skb->dev = to->dev; + skb_forward_csum(skb); + + NF_HOOK(NFPROTO_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 (to && 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, struct sk_buff *skb0) +{ + if (should_deliver(to, skb)) { + if (skb0) + deliver_clone(to, skb, __br_forward); + else + __br_forward(to, skb); + return; + } + + if (!skb0) + kfree_skb(skb); +} + +static int deliver_clone(const struct net_bridge_port *prev, + struct sk_buff *skb, + void (*__packet_hook)(const struct net_bridge_port *p, + struct sk_buff *skb)) +{ + struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; + + skb = skb_clone(skb, GFP_ATOMIC); + if (!skb) { + dev->stats.tx_dropped++; + return -ENOMEM; + } + + __packet_hook(prev, skb); + return 0; +} + +static struct net_bridge_port *maybe_deliver( + struct net_bridge_port *prev, struct net_bridge_port *p, + struct sk_buff *skb, + void (*__packet_hook)(const struct net_bridge_port *p, + struct sk_buff *skb)) +{ + int err; + + if (!should_deliver(p, skb)) + return prev; + + if (!prev) + goto out; + + err = deliver_clone(prev, skb, __packet_hook); + if (err) + return ERR_PTR(err); + +out: + return p; +} + +/* called under bridge lock */ +static void br_flood(struct net_bridge *br, struct sk_buff *skb, + struct sk_buff *skb0, + 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) { + prev = maybe_deliver(prev, p, skb, __packet_hook); + if (IS_ERR(prev)) + goto out; + } + + if (!prev) + goto out; + + if (skb0) + deliver_clone(prev, skb, __packet_hook); + else + __packet_hook(prev, skb); + return; + +out: + if (!skb0) + kfree_skb(skb); +} + + +/* called with rcu_read_lock */ +void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb) +{ + br_flood(br, skb, NULL, __br_deliver); +} + +/* called under bridge lock */ +void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, + struct sk_buff *skb2) +{ + br_flood(br, skb, skb2, __br_forward); +} + +#ifdef CONFIG_BRIDGE_IGMP_SNOOPING +/* called with rcu_read_lock */ +static void br_multicast_flood(struct net_bridge_mdb_entry *mdst, + struct sk_buff *skb, struct sk_buff *skb0, + void (*__packet_hook)( + const struct net_bridge_port *p, + struct sk_buff *skb)) +{ + struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; + struct net_bridge *br = netdev_priv(dev); + struct net_bridge_port *prev = NULL; + struct net_bridge_port_group *p; + struct hlist_node *rp; + + rp = rcu_dereference(hlist_first_rcu(&br->router_list)); + p = mdst ? rcu_dereference(mdst->ports) : NULL; + while (p || rp) { + struct net_bridge_port *port, *lport, *rport; + + lport = p ? p->port : NULL; + rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) : + NULL; + + port = (unsigned long)lport > (unsigned long)rport ? + lport : rport; + + prev = maybe_deliver(prev, port, skb, __packet_hook); + if (IS_ERR(prev)) + goto out; + + if ((unsigned long)lport >= (unsigned long)port) + p = rcu_dereference(p->next); + if ((unsigned long)rport >= (unsigned long)port) + rp = rcu_dereference(hlist_next_rcu(rp)); + } + + if (!prev) + goto out; + + if (skb0) + deliver_clone(prev, skb, __packet_hook); + else + __packet_hook(prev, skb); + return; + +out: + if (!skb0) + kfree_skb(skb); +} + +/* called with rcu_read_lock */ +void br_multicast_deliver(struct net_bridge_mdb_entry *mdst, + struct sk_buff *skb) +{ + br_multicast_flood(mdst, skb, NULL, __br_deliver); +} + +/* called with rcu_read_lock */ +void br_multicast_forward(struct net_bridge_mdb_entry *mdst, + struct sk_buff *skb, struct sk_buff *skb2) +{ + br_multicast_flood(mdst, skb, skb2, __br_forward); +} +#endif |