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![Bart De Schuymer](/assets/img/avatar_default.png)
The MTU for IP traffic encapsulated inside PPPoE traffic is smaller than the MTU of the Ethernet device (1500). Connection tracking gathers all IP packets and sometimes will refragment them in ip_fragment(). We then need to subtract the length of the encapsulating header from the mtu used in ip_fragment(). The check in br_nf_dev_queue_xmit() which determines if ip_fragment() has to be called is also updated for the PPPoE-encapsulated packets. nf_bridge_copy_header() is also updated to make sure the PPPoE data length field has the correct value. Signed-off-by: Bart De Schuymer <bdschuym@pandora.be> Signed-off-by: Patrick McHardy <kaber@trash.net>
113 lines
2.8 KiB
C
113 lines
2.8 KiB
C
#ifndef __LINUX_BRIDGE_NETFILTER_H
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#define __LINUX_BRIDGE_NETFILTER_H
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/* bridge-specific defines for netfilter.
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*/
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#include <linux/netfilter.h>
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#include <linux/if_ether.h>
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#include <linux/if_vlan.h>
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#include <linux/if_pppox.h>
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/* Bridge Hooks */
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/* After promisc drops, checksum checks. */
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#define NF_BR_PRE_ROUTING 0
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/* If the packet is destined for this box. */
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#define NF_BR_LOCAL_IN 1
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/* If the packet is destined for another interface. */
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#define NF_BR_FORWARD 2
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/* Packets coming from a local process. */
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#define NF_BR_LOCAL_OUT 3
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/* Packets about to hit the wire. */
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#define NF_BR_POST_ROUTING 4
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/* Not really a hook, but used for the ebtables broute table */
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#define NF_BR_BROUTING 5
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#define NF_BR_NUMHOOKS 6
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#ifdef __KERNEL__
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enum nf_br_hook_priorities {
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NF_BR_PRI_FIRST = INT_MIN,
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NF_BR_PRI_NAT_DST_BRIDGED = -300,
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NF_BR_PRI_FILTER_BRIDGED = -200,
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NF_BR_PRI_BRNF = 0,
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NF_BR_PRI_NAT_DST_OTHER = 100,
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NF_BR_PRI_FILTER_OTHER = 200,
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NF_BR_PRI_NAT_SRC = 300,
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NF_BR_PRI_LAST = INT_MAX,
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};
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#ifdef CONFIG_BRIDGE_NETFILTER
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#define BRNF_PKT_TYPE 0x01
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#define BRNF_BRIDGED_DNAT 0x02
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#define BRNF_BRIDGED 0x04
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#define BRNF_NF_BRIDGE_PREROUTING 0x08
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#define BRNF_8021Q 0x10
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#define BRNF_PPPoE 0x20
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/* Only used in br_forward.c */
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extern int nf_bridge_copy_header(struct sk_buff *skb);
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static inline int nf_bridge_maybe_copy_header(struct sk_buff *skb)
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{
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if (skb->nf_bridge &&
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skb->nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT))
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return nf_bridge_copy_header(skb);
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return 0;
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}
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static inline unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
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{
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switch (skb->protocol) {
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case __cpu_to_be16(ETH_P_8021Q):
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return VLAN_HLEN;
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case __cpu_to_be16(ETH_P_PPP_SES):
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return PPPOE_SES_HLEN;
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default:
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return 0;
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}
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}
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static inline unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
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{
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if (unlikely(skb->nf_bridge->mask & BRNF_PPPoE))
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return PPPOE_SES_HLEN;
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return 0;
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}
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extern int br_handle_frame_finish(struct sk_buff *skb);
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/* Only used in br_device.c */
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static inline int br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
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{
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struct nf_bridge_info *nf_bridge = skb->nf_bridge;
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skb_pull(skb, ETH_HLEN);
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nf_bridge->mask ^= BRNF_BRIDGED_DNAT;
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skb_copy_to_linear_data_offset(skb, -(ETH_HLEN-ETH_ALEN),
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skb->nf_bridge->data, ETH_HLEN-ETH_ALEN);
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skb->dev = nf_bridge->physindev;
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return br_handle_frame_finish(skb);
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}
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/* This is called by the IP fragmenting code and it ensures there is
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* enough room for the encapsulating header (if there is one). */
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static inline unsigned int nf_bridge_pad(const struct sk_buff *skb)
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{
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if (skb->nf_bridge)
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return nf_bridge_encap_header_len(skb);
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return 0;
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}
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struct bridge_skb_cb {
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union {
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__be32 ipv4;
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} daddr;
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};
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#else
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#define nf_bridge_maybe_copy_header(skb) (0)
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#define nf_bridge_pad(skb) (0)
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#endif /* CONFIG_BRIDGE_NETFILTER */
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#endif /* __KERNEL__ */
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#endif
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