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| 1 | /* |
| 2 | * Handle incoming frames |
| 3 | * Linux ethernet bridge |
| 4 | * |
| 5 | * Authors: |
| 6 | * Lennert Buytenhek <buytenh@gnu.org> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License |
| 10 | * as published by the Free Software Foundation; either version |
| 11 | * 2 of the License, or (at your option) any later version. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/netdevice.h> |
| 17 | #include <linux/etherdevice.h> |
| 18 | #include <linux/netfilter_bridge.h> |
| 19 | #include "br_private.h" |
| 20 | |
| 21 | /* Bridge group multicast address 802.1d (pg 51). */ |
| 22 | const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; |
| 23 | |
| 24 | /* Hook for brouter */ |
| 25 | br_should_route_hook_t __rcu *br_should_route_hook __read_mostly; |
| 26 | EXPORT_SYMBOL(br_should_route_hook); |
| 27 | |
| 28 | static int br_pass_frame_up(struct sk_buff *skb) |
| 29 | { |
| 30 | struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; |
| 31 | struct net_bridge *br = netdev_priv(brdev); |
| 32 | struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats); |
| 33 | |
| 34 | u64_stats_update_begin(&brstats->syncp); |
| 35 | brstats->rx_packets++; |
| 36 | brstats->rx_bytes += skb->len; |
| 37 | u64_stats_update_end(&brstats->syncp); |
| 38 | |
| 39 | indev = skb->dev; |
| 40 | skb->dev = brdev; |
| 41 | |
| 42 | return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
| 43 | netif_receive_skb); |
| 44 | } |
| 45 | |
| 46 | /* note: already called with rcu_read_lock */ |
| 47 | int br_handle_frame_finish(struct sk_buff *skb) |
| 48 | { |
| 49 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
| 50 | struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
| 51 | struct net_bridge *br; |
| 52 | struct net_bridge_fdb_entry *dst; |
| 53 | struct net_bridge_mdb_entry *mdst; |
| 54 | struct sk_buff *skb2; |
| 55 | |
| 56 | if (!p || p->state == BR_STATE_DISABLED) |
| 57 | goto drop; |
| 58 | |
| 59 | /* insert into forwarding database after filtering to avoid spoofing */ |
| 60 | br = p->br; |
| 61 | br_fdb_update(br, p, eth_hdr(skb)->h_source); |
| 62 | |
| 63 | if (is_multicast_ether_addr(dest) && |
| 64 | br_multicast_rcv(br, p, skb)) |
| 65 | goto drop; |
| 66 | |
| 67 | if (p->state == BR_STATE_LEARNING) |
| 68 | goto drop; |
| 69 | |
| 70 | BR_INPUT_SKB_CB(skb)->brdev = br->dev; |
| 71 | |
| 72 | /* The packet skb2 goes to the local host (NULL to skip). */ |
| 73 | skb2 = NULL; |
| 74 | |
| 75 | if (br->dev->flags & IFF_PROMISC) |
| 76 | skb2 = skb; |
| 77 | |
| 78 | dst = NULL; |
| 79 | |
| 80 | if (is_multicast_ether_addr(dest)) { |
| 81 | mdst = br_mdb_get(br, skb); |
| 82 | if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { |
| 83 | if ((mdst && mdst->mglist) || |
| 84 | br_multicast_is_router(br)) |
| 85 | skb2 = skb; |
| 86 | br_multicast_forward(mdst, skb, skb2); |
| 87 | skb = NULL; |
| 88 | if (!skb2) |
| 89 | goto out; |
| 90 | } else |
| 91 | skb2 = skb; |
| 92 | |
| 93 | br->dev->stats.multicast++; |
| 94 | } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) { |
| 95 | skb2 = skb; |
| 96 | /* Do not forward the packet since it's local. */ |
| 97 | skb = NULL; |
| 98 | } |
| 99 | |
| 100 | if (skb) { |
| 101 | if (dst) |
| 102 | br_forward(dst->dst, skb, skb2); |
| 103 | else |
| 104 | br_flood_forward(br, skb, skb2); |
| 105 | } |
| 106 | |
| 107 | if (skb2) |
| 108 | return br_pass_frame_up(skb2); |
| 109 | |
| 110 | out: |
| 111 | return 0; |
| 112 | drop: |
| 113 | kfree_skb(skb); |
| 114 | goto out; |
| 115 | } |
| 116 | |
| 117 | /* note: already called with rcu_read_lock */ |
| 118 | static int br_handle_local_finish(struct sk_buff *skb) |
| 119 | { |
| 120 | struct net_bridge_port *p = br_port_get_rcu(skb->dev); |
| 121 | |
| 122 | br_fdb_update(p->br, p, eth_hdr(skb)->h_source); |
| 123 | return 0; /* process further */ |
| 124 | } |
| 125 | |
| 126 | /* Does address match the link local multicast address. |
| 127 | * 01:80:c2:00:00:0X |
| 128 | */ |
| 129 | static inline int is_link_local(const unsigned char *dest) |
| 130 | { |
| 131 | __be16 *a = (__be16 *)dest; |
| 132 | static const __be16 *b = (const __be16 *)br_group_address; |
| 133 | static const __be16 m = cpu_to_be16(0xfff0); |
| 134 | |
| 135 | return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * Return NULL if skb is handled |
| 140 | * note: already called with rcu_read_lock |
| 141 | */ |
| 142 | rx_handler_result_t br_handle_frame(struct sk_buff **pskb) |
| 143 | { |
| 144 | struct net_bridge_port *p; |
| 145 | struct sk_buff *skb = *pskb; |
| 146 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
| 147 | br_should_route_hook_t *rhook; |
| 148 | |
| 149 | if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) |
| 150 | return RX_HANDLER_PASS; |
| 151 | |
| 152 | if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
| 153 | goto drop; |
| 154 | |
| 155 | skb = skb_share_check(skb, GFP_ATOMIC); |
| 156 | if (!skb) |
| 157 | return RX_HANDLER_CONSUMED; |
| 158 | |
| 159 | p = br_port_get_rcu(skb->dev); |
| 160 | |
| 161 | if (unlikely(is_link_local(dest))) { |
| 162 | /* Pause frames shouldn't be passed up by driver anyway */ |
| 163 | if (skb->protocol == htons(ETH_P_PAUSE)) |
| 164 | goto drop; |
| 165 | |
| 166 | /* If STP is turned off, then forward */ |
| 167 | if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0) |
| 168 | goto forward; |
| 169 | |
| 170 | if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
| 171 | NULL, br_handle_local_finish)) { |
| 172 | return RX_HANDLER_CONSUMED; /* consumed by filter */ |
| 173 | } else { |
| 174 | *pskb = skb; |
| 175 | return RX_HANDLER_PASS; /* continue processing */ |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | forward: |
| 180 | switch (p->state) { |
| 181 | case BR_STATE_FORWARDING: |
| 182 | rhook = rcu_dereference(br_should_route_hook); |
| 183 | if (rhook) { |
| 184 | if ((*rhook)(skb)) { |
| 185 | *pskb = skb; |
| 186 | return RX_HANDLER_PASS; |
| 187 | } |
| 188 | dest = eth_hdr(skb)->h_dest; |
| 189 | } |
| 190 | /* fall through */ |
| 191 | case BR_STATE_LEARNING: |
| 192 | if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
| 193 | skb->pkt_type = PACKET_HOST; |
| 194 | |
| 195 | NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
| 196 | br_handle_frame_finish); |
| 197 | break; |
| 198 | default: |
| 199 | drop: |
| 200 | kfree_skb(skb); |
| 201 | } |
| 202 | return RX_HANDLER_CONSUMED; |
| 203 | } |
| 204 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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