![Rami Rosen](/assets/img/avatar_default.png)
This patch fixes the following warning due to incompatible pointer
assignment:
net/bridge/br_netfilter.c: In function 'br_netfilter_rtable_init':
net/bridge/br_netfilter.c:116: warning: assignment from incompatible
pointer type
This warning is due to commit 4adf0af681
from July 30 (send correct MTU value in PMTU (revised)).
Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1008 lines
27 KiB
C
1008 lines
27 KiB
C
/*
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* Handle firewalling
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* Linux ethernet bridge
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*
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* Authors:
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* Lennert Buytenhek <buytenh@gnu.org>
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* Bart De Schuymer (maintainer) <bdschuym@pandora.be>
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*
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* Changes:
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* Apr 29 2003: physdev module support (bdschuym)
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* Jun 19 2003: let arptables see bridged ARP traffic (bdschuym)
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* Oct 06 2003: filter encapsulated IP/ARP VLAN traffic on untagged bridge
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* (bdschuym)
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* Sep 01 2004: add IPv6 filtering (bdschuym)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Lennert dedicates this file to Kerstin Wurdinger.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/ip.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/if_arp.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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#include <linux/ppp_defs.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_ipv6.h>
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#include <linux/netfilter_arp.h>
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#include <linux/in_route.h>
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#include <linux/inetdevice.h>
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#include <net/ip.h>
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#include <net/ipv6.h>
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#include <net/route.h>
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#include <asm/uaccess.h>
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#include "br_private.h"
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#ifdef CONFIG_SYSCTL
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#include <linux/sysctl.h>
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#endif
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#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
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(skb->nf_bridge->data))->daddr.ipv4)
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#define store_orig_dstaddr(skb) (skb_origaddr(skb) = ip_hdr(skb)->daddr)
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#define dnat_took_place(skb) (skb_origaddr(skb) != ip_hdr(skb)->daddr)
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#ifdef CONFIG_SYSCTL
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static struct ctl_table_header *brnf_sysctl_header;
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static int brnf_call_iptables __read_mostly = 1;
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static int brnf_call_ip6tables __read_mostly = 1;
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static int brnf_call_arptables __read_mostly = 1;
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static int brnf_filter_vlan_tagged __read_mostly = 1;
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static int brnf_filter_pppoe_tagged __read_mostly = 1;
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#else
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#define brnf_filter_vlan_tagged 1
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#define brnf_filter_pppoe_tagged 1
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#endif
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static inline __be16 vlan_proto(const struct sk_buff *skb)
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{
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return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
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}
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#define IS_VLAN_IP(skb) \
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(skb->protocol == htons(ETH_P_8021Q) && \
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vlan_proto(skb) == htons(ETH_P_IP) && \
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brnf_filter_vlan_tagged)
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#define IS_VLAN_IPV6(skb) \
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(skb->protocol == htons(ETH_P_8021Q) && \
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vlan_proto(skb) == htons(ETH_P_IPV6) &&\
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brnf_filter_vlan_tagged)
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#define IS_VLAN_ARP(skb) \
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(skb->protocol == htons(ETH_P_8021Q) && \
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vlan_proto(skb) == htons(ETH_P_ARP) && \
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brnf_filter_vlan_tagged)
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static inline __be16 pppoe_proto(const struct sk_buff *skb)
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{
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return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
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sizeof(struct pppoe_hdr)));
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}
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#define IS_PPPOE_IP(skb) \
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(skb->protocol == htons(ETH_P_PPP_SES) && \
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pppoe_proto(skb) == htons(PPP_IP) && \
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brnf_filter_pppoe_tagged)
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#define IS_PPPOE_IPV6(skb) \
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(skb->protocol == htons(ETH_P_PPP_SES) && \
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pppoe_proto(skb) == htons(PPP_IPV6) && \
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brnf_filter_pppoe_tagged)
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/*
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* Initialize bogus route table used to keep netfilter happy.
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* Currently, we fill in the PMTU entry because netfilter
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* refragmentation needs it, and the rt_flags entry because
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* ipt_REJECT needs it. Future netfilter modules might
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* require us to fill additional fields.
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*/
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void br_netfilter_rtable_init(struct net_bridge *br)
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{
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struct rtable *rt = &br->fake_rtable;
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atomic_set(&rt->u.dst.__refcnt, 1);
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rt->u.dst.dev = br->dev;
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rt->u.dst.path = &rt->u.dst;
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rt->u.dst.metrics[RTAX_MTU - 1] = 1500;
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rt->u.dst.flags = DST_NOXFRM;
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}
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static inline struct rtable *bridge_parent_rtable(const struct net_device *dev)
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{
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struct net_bridge_port *port = rcu_dereference(dev->br_port);
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return port ? &port->br->fake_rtable : NULL;
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}
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static inline struct net_device *bridge_parent(const struct net_device *dev)
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{
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struct net_bridge_port *port = rcu_dereference(dev->br_port);
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return port ? port->br->dev : NULL;
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}
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static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
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{
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skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
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if (likely(skb->nf_bridge))
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atomic_set(&(skb->nf_bridge->use), 1);
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return skb->nf_bridge;
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}
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static inline struct nf_bridge_info *nf_bridge_unshare(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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if (atomic_read(&nf_bridge->use) > 1) {
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struct nf_bridge_info *tmp = nf_bridge_alloc(skb);
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if (tmp) {
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memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info));
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atomic_set(&tmp->use, 1);
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nf_bridge_put(nf_bridge);
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}
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nf_bridge = tmp;
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}
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return nf_bridge;
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}
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static inline void nf_bridge_push_encap_header(struct sk_buff *skb)
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{
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unsigned int len = nf_bridge_encap_header_len(skb);
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skb_push(skb, len);
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skb->network_header -= len;
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}
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static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
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{
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unsigned int len = nf_bridge_encap_header_len(skb);
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skb_pull(skb, len);
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skb->network_header += len;
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}
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static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
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{
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unsigned int len = nf_bridge_encap_header_len(skb);
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skb_pull_rcsum(skb, len);
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skb->network_header += len;
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}
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static inline void nf_bridge_save_header(struct sk_buff *skb)
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{
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int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
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skb_copy_from_linear_data_offset(skb, -header_size,
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skb->nf_bridge->data, header_size);
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}
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/*
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* When forwarding bridge frames, we save a copy of the original
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* header before processing.
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*/
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int nf_bridge_copy_header(struct sk_buff *skb)
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{
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int err;
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int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
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err = skb_cow_head(skb, header_size);
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if (err)
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return err;
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skb_copy_to_linear_data_offset(skb, -header_size,
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skb->nf_bridge->data, header_size);
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__skb_push(skb, nf_bridge_encap_header_len(skb));
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return 0;
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}
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/* PF_BRIDGE/PRE_ROUTING *********************************************/
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/* Undo the changes made for ip6tables PREROUTING and continue the
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* bridge PRE_ROUTING hook. */
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static int br_nf_pre_routing_finish_ipv6(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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if (nf_bridge->mask & BRNF_PKT_TYPE) {
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skb->pkt_type = PACKET_OTHERHOST;
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nf_bridge->mask ^= BRNF_PKT_TYPE;
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}
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nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
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skb->rtable = bridge_parent_rtable(nf_bridge->physindev);
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if (!skb->rtable) {
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kfree_skb(skb);
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return 0;
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}
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dst_hold(&skb->rtable->u.dst);
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skb->dev = nf_bridge->physindev;
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nf_bridge_push_encap_header(skb);
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NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
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br_handle_frame_finish, 1);
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return 0;
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}
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static void __br_dnat_complain(void)
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{
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static unsigned long last_complaint;
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if (jiffies - last_complaint >= 5 * HZ) {
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printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
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"forwarding to be enabled\n");
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last_complaint = jiffies;
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}
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}
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/* This requires some explaining. If DNAT has taken place,
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* we will need to fix up the destination Ethernet address,
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* and this is a tricky process.
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*
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* There are two cases to consider:
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* 1. The packet was DNAT'ed to a device in the same bridge
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* port group as it was received on. We can still bridge
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* the packet.
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* 2. The packet was DNAT'ed to a different device, either
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* a non-bridged device or another bridge port group.
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* The packet will need to be routed.
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*
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* The correct way of distinguishing between these two cases is to
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* call ip_route_input() and to look at skb->dst->dev, which is
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* changed to the destination device if ip_route_input() succeeds.
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*
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* Let us first consider the case that ip_route_input() succeeds:
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*
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* If skb->dst->dev equals the logical bridge device the packet
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* came in on, we can consider this bridging. The packet is passed
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* through the neighbour output function to build a new destination
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* MAC address, which will make the packet enter br_nf_local_out()
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* not much later. In that function it is assured that the iptables
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* FORWARD chain is traversed for the packet.
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*
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* Otherwise, the packet is considered to be routed and we just
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* change the destination MAC address so that the packet will
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* later be passed up to the IP stack to be routed. For a redirected
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* packet, ip_route_input() will give back the localhost as output device,
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* which differs from the bridge device.
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*
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* Let us now consider the case that ip_route_input() fails:
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*
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* This can be because the destination address is martian, in which case
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* the packet will be dropped.
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* After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
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* will fail, while __ip_route_output_key() will return success. The source
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* address for __ip_route_output_key() is set to zero, so __ip_route_output_key
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* thinks we're handling a locally generated packet and won't care
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* if IP forwarding is allowed. We send a warning message to the users's
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* log telling her to put IP forwarding on.
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*
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* ip_route_input() will also fail if there is no route available.
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* In that case we just drop the packet.
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*
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* --Lennert, 20020411
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* --Bart, 20020416 (updated)
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* --Bart, 20021007 (updated)
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* --Bart, 20062711 (updated) */
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static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
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{
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if (skb->pkt_type == PACKET_OTHERHOST) {
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skb->pkt_type = PACKET_HOST;
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skb->nf_bridge->mask |= BRNF_PKT_TYPE;
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}
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skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
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skb->dev = bridge_parent(skb->dev);
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if (skb->dev) {
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struct dst_entry *dst = skb->dst;
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nf_bridge_pull_encap_header(skb);
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if (dst->hh)
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return neigh_hh_output(dst->hh, skb);
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else if (dst->neighbour)
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return dst->neighbour->output(skb);
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}
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kfree_skb(skb);
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return 0;
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}
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static int br_nf_pre_routing_finish(struct sk_buff *skb)
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{
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struct net_device *dev = skb->dev;
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struct iphdr *iph = ip_hdr(skb);
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struct nf_bridge_info *nf_bridge = skb->nf_bridge;
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int err;
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if (nf_bridge->mask & BRNF_PKT_TYPE) {
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skb->pkt_type = PACKET_OTHERHOST;
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nf_bridge->mask ^= BRNF_PKT_TYPE;
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}
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nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
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if (dnat_took_place(skb)) {
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if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
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struct rtable *rt;
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struct flowi fl = {
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.nl_u = {
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.ip4_u = {
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.daddr = iph->daddr,
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.saddr = 0,
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.tos = RT_TOS(iph->tos) },
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},
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.proto = 0,
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};
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struct in_device *in_dev = in_dev_get(dev);
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/* If err equals -EHOSTUNREACH the error is due to a
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* martian destination or due to the fact that
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* forwarding is disabled. For most martian packets,
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* ip_route_output_key() will fail. It won't fail for 2 types of
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* martian destinations: loopback destinations and destination
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* 0.0.0.0. In both cases the packet will be dropped because the
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* destination is the loopback device and not the bridge. */
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if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
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goto free_skb;
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if (!ip_route_output_key(&init_net, &rt, &fl)) {
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/* - Bridged-and-DNAT'ed traffic doesn't
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* require ip_forwarding. */
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if (((struct dst_entry *)rt)->dev == dev) {
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skb->dst = (struct dst_entry *)rt;
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goto bridged_dnat;
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}
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/* we are sure that forwarding is disabled, so printing
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* this message is no problem. Note that the packet could
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* still have a martian destination address, in which case
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* the packet could be dropped even if forwarding were enabled */
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__br_dnat_complain();
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dst_release((struct dst_entry *)rt);
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}
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free_skb:
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kfree_skb(skb);
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return 0;
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} else {
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if (skb->dst->dev == dev) {
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bridged_dnat:
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/* Tell br_nf_local_out this is a
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* bridged frame */
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nf_bridge->mask |= BRNF_BRIDGED_DNAT;
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skb->dev = nf_bridge->physindev;
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nf_bridge_push_encap_header(skb);
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NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
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skb, skb->dev, NULL,
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br_nf_pre_routing_finish_bridge,
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1);
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return 0;
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}
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memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
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skb->pkt_type = PACKET_HOST;
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}
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} else {
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skb->rtable = bridge_parent_rtable(nf_bridge->physindev);
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if (!skb->rtable) {
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kfree_skb(skb);
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return 0;
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}
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dst_hold(&skb->rtable->u.dst);
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}
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skb->dev = nf_bridge->physindev;
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nf_bridge_push_encap_header(skb);
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NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
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br_handle_frame_finish, 1);
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return 0;
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}
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/* Some common code for IPv4/IPv6 */
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static struct net_device *setup_pre_routing(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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if (skb->pkt_type == PACKET_OTHERHOST) {
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skb->pkt_type = PACKET_HOST;
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nf_bridge->mask |= BRNF_PKT_TYPE;
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}
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nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
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nf_bridge->physindev = skb->dev;
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skb->dev = bridge_parent(skb->dev);
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return skb->dev;
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}
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/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
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static int check_hbh_len(struct sk_buff *skb)
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{
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unsigned char *raw = (u8 *)(ipv6_hdr(skb) + 1);
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u32 pkt_len;
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const unsigned char *nh = skb_network_header(skb);
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int off = raw - nh;
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int len = (raw[1] + 1) << 3;
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if ((raw + len) - skb->data > skb_headlen(skb))
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goto bad;
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off += 2;
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len -= 2;
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while (len > 0) {
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int optlen = nh[off + 1] + 2;
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switch (nh[off]) {
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case IPV6_TLV_PAD0:
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optlen = 1;
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break;
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case IPV6_TLV_PADN:
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break;
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case IPV6_TLV_JUMBO:
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if (nh[off + 1] != 4 || (off & 3) != 2)
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goto bad;
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pkt_len = ntohl(*(__be32 *) (nh + off + 2));
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if (pkt_len <= IPV6_MAXPLEN ||
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ipv6_hdr(skb)->payload_len)
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goto bad;
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if (pkt_len > skb->len - sizeof(struct ipv6hdr))
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goto bad;
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if (pskb_trim_rcsum(skb,
|
|
pkt_len + sizeof(struct ipv6hdr)))
|
|
goto bad;
|
|
nh = skb_network_header(skb);
|
|
break;
|
|
default:
|
|
if (optlen > len)
|
|
goto bad;
|
|
break;
|
|
}
|
|
off += optlen;
|
|
len -= optlen;
|
|
}
|
|
if (len == 0)
|
|
return 0;
|
|
bad:
|
|
return -1;
|
|
|
|
}
|
|
|
|
/* Replicate the checks that IPv6 does on packet reception and pass the packet
|
|
* to ip6tables, which doesn't support NAT, so things are fairly simple. */
|
|
static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
|
|
struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct ipv6hdr *hdr;
|
|
u32 pkt_len;
|
|
|
|
if (skb->len < sizeof(struct ipv6hdr))
|
|
goto inhdr_error;
|
|
|
|
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
|
|
goto inhdr_error;
|
|
|
|
hdr = ipv6_hdr(skb);
|
|
|
|
if (hdr->version != 6)
|
|
goto inhdr_error;
|
|
|
|
pkt_len = ntohs(hdr->payload_len);
|
|
|
|
if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
|
|
if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
|
|
goto inhdr_error;
|
|
if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
|
|
goto inhdr_error;
|
|
}
|
|
if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
|
|
goto inhdr_error;
|
|
|
|
nf_bridge_put(skb->nf_bridge);
|
|
if (!nf_bridge_alloc(skb))
|
|
return NF_DROP;
|
|
if (!setup_pre_routing(skb))
|
|
return NF_DROP;
|
|
|
|
NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
|
|
br_nf_pre_routing_finish_ipv6);
|
|
|
|
return NF_STOLEN;
|
|
|
|
inhdr_error:
|
|
return NF_DROP;
|
|
}
|
|
|
|
/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
|
|
* Replicate the checks that IPv4 does on packet reception.
|
|
* Set skb->dev to the bridge device (i.e. parent of the
|
|
* receiving device) to make netfilter happy, the REDIRECT
|
|
* target in particular. Save the original destination IP
|
|
* address to be able to detect DNAT afterwards. */
|
|
static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct iphdr *iph;
|
|
__u32 len = nf_bridge_encap_header_len(skb);
|
|
|
|
if (unlikely(!pskb_may_pull(skb, len)))
|
|
goto out;
|
|
|
|
if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb) ||
|
|
IS_PPPOE_IPV6(skb)) {
|
|
#ifdef CONFIG_SYSCTL
|
|
if (!brnf_call_ip6tables)
|
|
return NF_ACCEPT;
|
|
#endif
|
|
nf_bridge_pull_encap_header_rcsum(skb);
|
|
return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
|
|
}
|
|
#ifdef CONFIG_SYSCTL
|
|
if (!brnf_call_iptables)
|
|
return NF_ACCEPT;
|
|
#endif
|
|
|
|
if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb) &&
|
|
!IS_PPPOE_IP(skb))
|
|
return NF_ACCEPT;
|
|
|
|
nf_bridge_pull_encap_header_rcsum(skb);
|
|
|
|
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
|
|
goto inhdr_error;
|
|
|
|
iph = ip_hdr(skb);
|
|
if (iph->ihl < 5 || iph->version != 4)
|
|
goto inhdr_error;
|
|
|
|
if (!pskb_may_pull(skb, 4 * iph->ihl))
|
|
goto inhdr_error;
|
|
|
|
iph = ip_hdr(skb);
|
|
if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
|
|
goto inhdr_error;
|
|
|
|
len = ntohs(iph->tot_len);
|
|
if (skb->len < len || len < 4 * iph->ihl)
|
|
goto inhdr_error;
|
|
|
|
pskb_trim_rcsum(skb, len);
|
|
|
|
nf_bridge_put(skb->nf_bridge);
|
|
if (!nf_bridge_alloc(skb))
|
|
return NF_DROP;
|
|
if (!setup_pre_routing(skb))
|
|
return NF_DROP;
|
|
store_orig_dstaddr(skb);
|
|
|
|
NF_HOOK(PF_INET, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
|
|
br_nf_pre_routing_finish);
|
|
|
|
return NF_STOLEN;
|
|
|
|
inhdr_error:
|
|
// IP_INC_STATS_BH(IpInHdrErrors);
|
|
out:
|
|
return NF_DROP;
|
|
}
|
|
|
|
|
|
/* PF_BRIDGE/LOCAL_IN ************************************************/
|
|
/* The packet is locally destined, which requires a real
|
|
* dst_entry, so detach the fake one. On the way up, the
|
|
* packet would pass through PRE_ROUTING again (which already
|
|
* took place when the packet entered the bridge), but we
|
|
* register an IPv4 PRE_ROUTING 'sabotage' hook that will
|
|
* prevent this from happening. */
|
|
static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
if (skb->rtable && skb->rtable == bridge_parent_rtable(in)) {
|
|
dst_release(&skb->rtable->u.dst);
|
|
skb->rtable = NULL;
|
|
}
|
|
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
/* PF_BRIDGE/FORWARD *************************************************/
|
|
static int br_nf_forward_finish(struct sk_buff *skb)
|
|
{
|
|
struct nf_bridge_info *nf_bridge = skb->nf_bridge;
|
|
struct net_device *in;
|
|
|
|
if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
|
|
in = nf_bridge->physindev;
|
|
if (nf_bridge->mask & BRNF_PKT_TYPE) {
|
|
skb->pkt_type = PACKET_OTHERHOST;
|
|
nf_bridge->mask ^= BRNF_PKT_TYPE;
|
|
}
|
|
} else {
|
|
in = *((struct net_device **)(skb->cb));
|
|
}
|
|
nf_bridge_push_encap_header(skb);
|
|
NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
|
|
skb->dev, br_forward_finish, 1);
|
|
return 0;
|
|
}
|
|
|
|
/* This is the 'purely bridged' case. For IP, we pass the packet to
|
|
* netfilter with indev and outdev set to the bridge device,
|
|
* but we are still able to filter on the 'real' indev/outdev
|
|
* because of the physdev module. For ARP, indev and outdev are the
|
|
* bridge ports. */
|
|
static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct nf_bridge_info *nf_bridge;
|
|
struct net_device *parent;
|
|
int pf;
|
|
|
|
if (!skb->nf_bridge)
|
|
return NF_ACCEPT;
|
|
|
|
/* Need exclusive nf_bridge_info since we might have multiple
|
|
* different physoutdevs. */
|
|
if (!nf_bridge_unshare(skb))
|
|
return NF_DROP;
|
|
|
|
parent = bridge_parent(out);
|
|
if (!parent)
|
|
return NF_DROP;
|
|
|
|
if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb) ||
|
|
IS_PPPOE_IP(skb))
|
|
pf = PF_INET;
|
|
else
|
|
pf = PF_INET6;
|
|
|
|
nf_bridge_pull_encap_header(skb);
|
|
|
|
nf_bridge = skb->nf_bridge;
|
|
if (skb->pkt_type == PACKET_OTHERHOST) {
|
|
skb->pkt_type = PACKET_HOST;
|
|
nf_bridge->mask |= BRNF_PKT_TYPE;
|
|
}
|
|
|
|
/* The physdev module checks on this */
|
|
nf_bridge->mask |= BRNF_BRIDGED;
|
|
nf_bridge->physoutdev = skb->dev;
|
|
|
|
NF_HOOK(pf, NF_INET_FORWARD, skb, bridge_parent(in), parent,
|
|
br_nf_forward_finish);
|
|
|
|
return NF_STOLEN;
|
|
}
|
|
|
|
static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct net_device **d = (struct net_device **)(skb->cb);
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
if (!brnf_call_arptables)
|
|
return NF_ACCEPT;
|
|
#endif
|
|
|
|
if (skb->protocol != htons(ETH_P_ARP)) {
|
|
if (!IS_VLAN_ARP(skb))
|
|
return NF_ACCEPT;
|
|
nf_bridge_pull_encap_header(skb);
|
|
}
|
|
|
|
if (arp_hdr(skb)->ar_pln != 4) {
|
|
if (IS_VLAN_ARP(skb))
|
|
nf_bridge_push_encap_header(skb);
|
|
return NF_ACCEPT;
|
|
}
|
|
*d = (struct net_device *)in;
|
|
NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
|
|
(struct net_device *)out, br_nf_forward_finish);
|
|
|
|
return NF_STOLEN;
|
|
}
|
|
|
|
/* PF_BRIDGE/LOCAL_OUT ***********************************************
|
|
*
|
|
* This function sees both locally originated IP packets and forwarded
|
|
* IP packets (in both cases the destination device is a bridge
|
|
* device). It also sees bridged-and-DNAT'ed packets.
|
|
*
|
|
* If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
|
|
* and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
|
|
* will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
|
|
* NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
|
|
* will be executed.
|
|
*/
|
|
static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct net_device *realindev;
|
|
struct nf_bridge_info *nf_bridge;
|
|
|
|
if (!skb->nf_bridge)
|
|
return NF_ACCEPT;
|
|
|
|
/* Need exclusive nf_bridge_info since we might have multiple
|
|
* different physoutdevs. */
|
|
if (!nf_bridge_unshare(skb))
|
|
return NF_DROP;
|
|
|
|
nf_bridge = skb->nf_bridge;
|
|
if (!(nf_bridge->mask & BRNF_BRIDGED_DNAT))
|
|
return NF_ACCEPT;
|
|
|
|
/* Bridged, take PF_BRIDGE/FORWARD.
|
|
* (see big note in front of br_nf_pre_routing_finish) */
|
|
nf_bridge->physoutdev = skb->dev;
|
|
realindev = nf_bridge->physindev;
|
|
|
|
if (nf_bridge->mask & BRNF_PKT_TYPE) {
|
|
skb->pkt_type = PACKET_OTHERHOST;
|
|
nf_bridge->mask ^= BRNF_PKT_TYPE;
|
|
}
|
|
nf_bridge_push_encap_header(skb);
|
|
|
|
NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev, skb->dev,
|
|
br_forward_finish);
|
|
return NF_STOLEN;
|
|
}
|
|
|
|
static int br_nf_dev_queue_xmit(struct sk_buff *skb)
|
|
{
|
|
if (skb->protocol == htons(ETH_P_IP) &&
|
|
skb->len > skb->dev->mtu &&
|
|
!skb_is_gso(skb))
|
|
return ip_fragment(skb, br_dev_queue_push_xmit);
|
|
else
|
|
return br_dev_queue_push_xmit(skb);
|
|
}
|
|
|
|
/* PF_BRIDGE/POST_ROUTING ********************************************/
|
|
static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct nf_bridge_info *nf_bridge = skb->nf_bridge;
|
|
struct net_device *realoutdev = bridge_parent(skb->dev);
|
|
int pf;
|
|
|
|
#ifdef CONFIG_NETFILTER_DEBUG
|
|
/* Be very paranoid. This probably won't happen anymore, but let's
|
|
* keep the check just to be sure... */
|
|
if (skb_mac_header(skb) < skb->head ||
|
|
skb_mac_header(skb) + ETH_HLEN > skb->data) {
|
|
printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
|
|
"bad mac.raw pointer.\n");
|
|
goto print_error;
|
|
}
|
|
#endif
|
|
|
|
if (!nf_bridge)
|
|
return NF_ACCEPT;
|
|
|
|
if (!(nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT)))
|
|
return NF_ACCEPT;
|
|
|
|
if (!realoutdev)
|
|
return NF_DROP;
|
|
|
|
if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb) ||
|
|
IS_PPPOE_IP(skb))
|
|
pf = PF_INET;
|
|
else
|
|
pf = PF_INET6;
|
|
|
|
#ifdef CONFIG_NETFILTER_DEBUG
|
|
if (skb->dst == NULL) {
|
|
printk(KERN_INFO "br_netfilter post_routing: skb->dst == NULL\n");
|
|
goto print_error;
|
|
}
|
|
#endif
|
|
|
|
/* We assume any code from br_dev_queue_push_xmit onwards doesn't care
|
|
* about the value of skb->pkt_type. */
|
|
if (skb->pkt_type == PACKET_OTHERHOST) {
|
|
skb->pkt_type = PACKET_HOST;
|
|
nf_bridge->mask |= BRNF_PKT_TYPE;
|
|
}
|
|
|
|
nf_bridge_pull_encap_header(skb);
|
|
nf_bridge_save_header(skb);
|
|
|
|
NF_HOOK(pf, NF_INET_POST_ROUTING, skb, NULL, realoutdev,
|
|
br_nf_dev_queue_xmit);
|
|
|
|
return NF_STOLEN;
|
|
|
|
#ifdef CONFIG_NETFILTER_DEBUG
|
|
print_error:
|
|
if (skb->dev != NULL) {
|
|
printk("[%s]", skb->dev->name);
|
|
if (realoutdev)
|
|
printk("[%s]", realoutdev->name);
|
|
}
|
|
printk(" head:%p, raw:%p, data:%p\n", skb->head, skb_mac_header(skb),
|
|
skb->data);
|
|
dump_stack();
|
|
return NF_ACCEPT;
|
|
#endif
|
|
}
|
|
|
|
/* IP/SABOTAGE *****************************************************/
|
|
/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
|
|
* for the second time. */
|
|
static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
if (skb->nf_bridge &&
|
|
!(skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
|
|
return NF_STOP;
|
|
}
|
|
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
/* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
|
|
* PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
|
|
* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
|
|
* ip_refrag() can return NF_STOLEN. */
|
|
static struct nf_hook_ops br_nf_ops[] __read_mostly = {
|
|
{ .hook = br_nf_pre_routing,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_BRIDGE,
|
|
.hooknum = NF_BR_PRE_ROUTING,
|
|
.priority = NF_BR_PRI_BRNF, },
|
|
{ .hook = br_nf_local_in,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_BRIDGE,
|
|
.hooknum = NF_BR_LOCAL_IN,
|
|
.priority = NF_BR_PRI_BRNF, },
|
|
{ .hook = br_nf_forward_ip,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_BRIDGE,
|
|
.hooknum = NF_BR_FORWARD,
|
|
.priority = NF_BR_PRI_BRNF - 1, },
|
|
{ .hook = br_nf_forward_arp,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_BRIDGE,
|
|
.hooknum = NF_BR_FORWARD,
|
|
.priority = NF_BR_PRI_BRNF, },
|
|
{ .hook = br_nf_local_out,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_BRIDGE,
|
|
.hooknum = NF_BR_LOCAL_OUT,
|
|
.priority = NF_BR_PRI_FIRST, },
|
|
{ .hook = br_nf_post_routing,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_BRIDGE,
|
|
.hooknum = NF_BR_POST_ROUTING,
|
|
.priority = NF_BR_PRI_LAST, },
|
|
{ .hook = ip_sabotage_in,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET,
|
|
.hooknum = NF_INET_PRE_ROUTING,
|
|
.priority = NF_IP_PRI_FIRST, },
|
|
{ .hook = ip_sabotage_in,
|
|
.owner = THIS_MODULE,
|
|
.pf = PF_INET6,
|
|
.hooknum = NF_INET_PRE_ROUTING,
|
|
.priority = NF_IP6_PRI_FIRST, },
|
|
};
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
static
|
|
int brnf_sysctl_call_tables(ctl_table * ctl, int write, struct file *filp,
|
|
void __user * buffer, size_t * lenp, loff_t * ppos)
|
|
{
|
|
int ret;
|
|
|
|
ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
|
|
|
|
if (write && *(int *)(ctl->data))
|
|
*(int *)(ctl->data) = 1;
|
|
return ret;
|
|
}
|
|
|
|
static ctl_table brnf_table[] = {
|
|
{
|
|
.procname = "bridge-nf-call-arptables",
|
|
.data = &brnf_call_arptables,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &brnf_sysctl_call_tables,
|
|
},
|
|
{
|
|
.procname = "bridge-nf-call-iptables",
|
|
.data = &brnf_call_iptables,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &brnf_sysctl_call_tables,
|
|
},
|
|
{
|
|
.procname = "bridge-nf-call-ip6tables",
|
|
.data = &brnf_call_ip6tables,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &brnf_sysctl_call_tables,
|
|
},
|
|
{
|
|
.procname = "bridge-nf-filter-vlan-tagged",
|
|
.data = &brnf_filter_vlan_tagged,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &brnf_sysctl_call_tables,
|
|
},
|
|
{
|
|
.procname = "bridge-nf-filter-pppoe-tagged",
|
|
.data = &brnf_filter_pppoe_tagged,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &brnf_sysctl_call_tables,
|
|
},
|
|
{ .ctl_name = 0 }
|
|
};
|
|
|
|
static struct ctl_path brnf_path[] = {
|
|
{ .procname = "net", .ctl_name = CTL_NET, },
|
|
{ .procname = "bridge", .ctl_name = NET_BRIDGE, },
|
|
{ }
|
|
};
|
|
#endif
|
|
|
|
int __init br_netfilter_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = nf_register_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
|
|
if (ret < 0)
|
|
return ret;
|
|
#ifdef CONFIG_SYSCTL
|
|
brnf_sysctl_header = register_sysctl_paths(brnf_path, brnf_table);
|
|
if (brnf_sysctl_header == NULL) {
|
|
printk(KERN_WARNING
|
|
"br_netfilter: can't register to sysctl.\n");
|
|
nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
|
|
return -ENOMEM;
|
|
}
|
|
#endif
|
|
printk(KERN_NOTICE "Bridge firewalling registered\n");
|
|
return 0;
|
|
}
|
|
|
|
void br_netfilter_fini(void)
|
|
{
|
|
nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
|
|
#ifdef CONFIG_SYSCTL
|
|
unregister_sysctl_table(brnf_sysctl_header);
|
|
#endif
|
|
}
|