| /* |
| * Handle incoming frames |
| * 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/slab.h> |
| #include <linux/kernel.h> |
| #include <linux/netdevice.h> |
| #include <linux/etherdevice.h> |
| #include <linux/netfilter_bridge.h> |
| #include <linux/export.h> |
| #include <linux/rculist.h> |
| #include "br_private.h" |
| |
| /* Hook for brouter */ |
| br_should_route_hook_t __rcu *br_should_route_hook __read_mostly; |
| EXPORT_SYMBOL(br_should_route_hook); |
| |
| static int br_pass_frame_up(struct sk_buff *skb) |
| { |
| struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; |
| struct net_bridge *br = netdev_priv(brdev); |
| struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats); |
| |
| u64_stats_update_begin(&brstats->syncp); |
| brstats->rx_packets++; |
| brstats->rx_bytes += skb->len; |
| u64_stats_update_end(&brstats->syncp); |
| |
| /* Bridge is just like any other port. Make sure the |
| * packet is allowed except in promisc modue when someone |
| * may be running packet capture. |
| */ |
| if (!(brdev->flags & IFF_PROMISC) && |
| !br_allowed_egress(br, br_get_vlan_info(br), skb)) { |
| kfree_skb(skb); |
| return NET_RX_DROP; |
| } |
| |
| skb = br_handle_vlan(br, br_get_vlan_info(br), skb); |
| if (!skb) |
| return NET_RX_DROP; |
| |
| indev = skb->dev; |
| skb->dev = brdev; |
| |
| return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
| netif_receive_skb); |
| } |
| |
| /* note: already called with rcu_read_lock */ |
| int br_handle_frame_finish(struct sk_buff *skb) |
| { |
| const unsigned char *dest = eth_hdr(skb)->h_dest; |
| struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
| struct net_bridge *br; |
| struct net_bridge_fdb_entry *dst; |
| struct net_bridge_mdb_entry *mdst; |
| struct sk_buff *skb2; |
| u16 vid = 0; |
| |
| if (!p || p->state == BR_STATE_DISABLED) |
| goto drop; |
| |
| if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid)) |
| goto out; |
| |
| /* insert into forwarding database after filtering to avoid spoofing */ |
| br = p->br; |
| br_fdb_update(br, p, eth_hdr(skb)->h_source, vid); |
| |
| if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) && |
| br_multicast_rcv(br, p, skb)) |
| goto drop; |
| |
| if (p->state == BR_STATE_LEARNING) |
| goto drop; |
| |
| BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
| |
| /* The packet skb2 goes to the local host (NULL to skip). */ |
| skb2 = NULL; |
| |
| if (br->dev->flags & IFF_PROMISC) |
| skb2 = skb; |
| |
| dst = NULL; |
| |
| if (is_broadcast_ether_addr(dest)) |
| skb2 = skb; |
| else if (is_multicast_ether_addr(dest)) { |
| mdst = br_mdb_get(br, skb, vid); |
| if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { |
| if ((mdst && mdst->mglist) || |
| br_multicast_is_router(br)) |
| skb2 = skb; |
| br_multicast_forward(mdst, skb, skb2); |
| skb = NULL; |
| if (!skb2) |
| goto out; |
| } else |
| skb2 = skb; |
| |
| br->dev->stats.multicast++; |
| } else if ((dst = __br_fdb_get(br, dest, vid)) && |
| dst->is_local) { |
| skb2 = skb; |
| /* Do not forward the packet since it's local. */ |
| skb = NULL; |
| } |
| |
| if (skb) { |
| if (dst) { |
| dst->used = jiffies; |
| br_forward(dst->dst, skb, skb2); |
| } else |
| br_flood_forward(br, skb, skb2); |
| } |
| |
| if (skb2) |
| return br_pass_frame_up(skb2); |
| |
| out: |
| return 0; |
| drop: |
| kfree_skb(skb); |
| goto out; |
| } |
| |
| /* note: already called with rcu_read_lock */ |
| static int br_handle_local_finish(struct sk_buff *skb) |
| { |
| struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
| u16 vid = 0; |
| |
| br_vlan_get_tag(skb, &vid); |
| br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid); |
| return 0; /* process further */ |
| } |
| |
| /* |
| * Return NULL if skb is handled |
| * note: already called with rcu_read_lock |
| */ |
| rx_handler_result_t br_handle_frame(struct sk_buff **pskb) |
| { |
| struct net_bridge_port *p; |
| struct sk_buff *skb = *pskb; |
| const unsigned char *dest = eth_hdr(skb)->h_dest; |
| br_should_route_hook_t *rhook; |
| |
| if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) |
| return RX_HANDLER_PASS; |
| |
| if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
| goto drop; |
| |
| skb = skb_share_check(skb, GFP_ATOMIC); |
| if (!skb) |
| return RX_HANDLER_CONSUMED; |
| |
| p = br_port_get_rcu(skb->dev); |
| |
| if (unlikely(is_link_local_ether_addr(dest))) { |
| /* |
| * See IEEE 802.1D Table 7-10 Reserved addresses |
| * |
| * Assignment Value |
| * Bridge Group Address 01-80-C2-00-00-00 |
| * (MAC Control) 802.3 01-80-C2-00-00-01 |
| * (Link Aggregation) 802.3 01-80-C2-00-00-02 |
| * 802.1X PAE address 01-80-C2-00-00-03 |
| * |
| * 802.1AB LLDP 01-80-C2-00-00-0E |
| * |
| * Others reserved for future standardization |
| */ |
| switch (dest[5]) { |
| case 0x00: /* Bridge Group Address */ |
| /* If STP is turned off, |
| then must forward to keep loop detection */ |
| if (p->br->stp_enabled == BR_NO_STP) |
| goto forward; |
| break; |
| |
| case 0x01: /* IEEE MAC (Pause) */ |
| goto drop; |
| |
| default: |
| /* Allow selective forwarding for most other protocols */ |
| if (p->br->group_fwd_mask & (1u << dest[5])) |
| goto forward; |
| } |
| |
| /* Deliver packet to local host only */ |
| if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
| NULL, br_handle_local_finish)) { |
| return RX_HANDLER_CONSUMED; /* consumed by filter */ |
| } else { |
| *pskb = skb; |
| return RX_HANDLER_PASS; /* continue processing */ |
| } |
| } |
| |
| forward: |
| switch (p->state) { |
| case BR_STATE_FORWARDING: |
| rhook = rcu_dereference(br_should_route_hook); |
| if (rhook) { |
| if ((*rhook)(skb)) { |
| *pskb = skb; |
| return RX_HANDLER_PASS; |
| } |
| dest = eth_hdr(skb)->h_dest; |
| } |
| /* fall through */ |
| case BR_STATE_LEARNING: |
| if (ether_addr_equal(p->br->dev->dev_addr, dest)) |
| skb->pkt_type = PACKET_HOST; |
| |
| NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
| br_handle_frame_finish); |
| break; |
| default: |
| drop: |
| kfree_skb(skb); |
| } |
| return RX_HANDLER_CONSUMED; |
| } |