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- /*
- * Handle firewalling
- * Linux ethernet bridge
- *
- * Authors:
- * Lennert Buytenhek <buytenh@gnu.org>
- * Bart De Schuymer (maintainer) <bdschuym@pandora.be>
- *
- * Changes:
- * Apr 29 2003: physdev module support (bdschuym)
- * Jun 19 2003: let arptables see bridged ARP traffic (bdschuym)
- * Oct 06 2003: filter encapsulated IP/ARP VLAN traffic on untagged bridge
- * (bdschuym)
- * Sep 01 2004: add IPv6 filtering (bdschuym)
- *
- * 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.
- *
- * Lennert dedicates this file to Kerstin Wurdinger.
- */
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/ip.h>
- #include <linux/netdevice.h>
- #include <linux/skbuff.h>
- #include <linux/if_arp.h>
- #include <linux/if_ether.h>
- #include <linux/if_vlan.h>
- #include <linux/netfilter_bridge.h>
- #include <linux/netfilter_ipv4.h>
- #include <linux/netfilter_ipv6.h>
- #include <linux/netfilter_arp.h>
- #include <linux/in_route.h>
- #include <linux/inetdevice.h>
- #include <net/ip.h>
- #include <net/ipv6.h>
- #include <net/route.h>
- #include <asm/uaccess.h>
- #include "br_private.h"
- #ifdef CONFIG_SYSCTL
- #include <linux/sysctl.h>
- #endif
- #define skb_origaddr(skb) (((struct bridge_skb_cb *) \
- (skb->nf_bridge->data))->daddr.ipv4)
- #define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
- #define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
- #ifdef CONFIG_SYSCTL
- static struct ctl_table_header *brnf_sysctl_header;
- static int brnf_call_iptables __read_mostly = 1;
- static int brnf_call_ip6tables __read_mostly = 1;
- static int brnf_call_arptables __read_mostly = 1;
- static int brnf_filter_vlan_tagged __read_mostly = 1;
- #else
- #define brnf_filter_vlan_tagged 1
- #endif
- static inline __be16 vlan_proto(const struct sk_buff *skb)
- {
- return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
- }
- #define IS_VLAN_IP(skb) \
- (skb->protocol == htons(ETH_P_8021Q) && \
- vlan_proto(skb) == htons(ETH_P_IP) && \
- brnf_filter_vlan_tagged)
- #define IS_VLAN_IPV6(skb) \
- (skb->protocol == htons(ETH_P_8021Q) && \
- vlan_proto(skb) == htons(ETH_P_IPV6) &&\
- brnf_filter_vlan_tagged)
- #define IS_VLAN_ARP(skb) \
- (skb->protocol == htons(ETH_P_8021Q) && \
- vlan_proto(skb) == htons(ETH_P_ARP) && \
- brnf_filter_vlan_tagged)
- /* We need these fake structures to make netfilter happy --
- * lots of places assume that skb->dst != NULL, which isn't
- * all that unreasonable.
- *
- * Currently, we fill in the PMTU entry because netfilter
- * refragmentation needs it, and the rt_flags entry because
- * ipt_REJECT needs it. Future netfilter modules might
- * require us to fill additional fields. */
- static struct net_device __fake_net_device = {
- .hard_header_len = ETH_HLEN
- };
- static struct rtable __fake_rtable = {
- .u = {
- .dst = {
- .__refcnt = ATOMIC_INIT(1),
- .dev = &__fake_net_device,
- .path = &__fake_rtable.u.dst,
- .metrics = {[RTAX_MTU - 1] = 1500},
- .flags = DST_NOXFRM,
- }
- },
- .rt_flags = 0,
- };
- static inline struct net_device *bridge_parent(const struct net_device *dev)
- {
- struct net_bridge_port *port = rcu_dereference(dev->br_port);
- return port ? port->br->dev : NULL;
- }
- static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
- {
- skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
- if (likely(skb->nf_bridge))
- atomic_set(&(skb->nf_bridge->use), 1);
- return skb->nf_bridge;
- }
- static inline void nf_bridge_save_header(struct sk_buff *skb)
- {
- int header_size = ETH_HLEN;
- if (skb->protocol == htons(ETH_P_8021Q))
- header_size += VLAN_HLEN;
- memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
- }
- /*
- * When forwarding bridge frames, we save a copy of the original
- * header before processing.
- */
- int nf_bridge_copy_header(struct sk_buff *skb)
- {
- int err;
- int header_size = ETH_HLEN;
- if (skb->protocol == htons(ETH_P_8021Q))
- header_size += VLAN_HLEN;
- err = skb_cow(skb, header_size);
- if (err)
- return err;
- memcpy(skb->data - header_size, skb->nf_bridge->data, header_size);
- if (skb->protocol == htons(ETH_P_8021Q))
- __skb_push(skb, VLAN_HLEN);
- return 0;
- }
- /* PF_BRIDGE/PRE_ROUTING *********************************************/
- /* Undo the changes made for ip6tables PREROUTING and continue the
- * bridge PRE_ROUTING hook. */
- static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
- {
- struct nf_bridge_info *nf_bridge = skb->nf_bridge;
- if (nf_bridge->mask & BRNF_PKT_TYPE) {
- skb->pkt_type = PACKET_OTHERHOST;
- nf_bridge->mask ^= BRNF_PKT_TYPE;
- }
- nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
- skb->dst = (struct dst_entry *)&__fake_rtable;
- dst_hold(skb->dst);
- skb->dev = nf_bridge->physindev;
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_push(skb, VLAN_HLEN);
- skb->nh.raw -= VLAN_HLEN;
- }
- NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
- br_handle_frame_finish, 1);
- return 0;
- }
- static void __br_dnat_complain(void)
- {
- static unsigned long last_complaint;
- if (jiffies - last_complaint >= 5 * HZ) {
- printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
- "forwarding to be enabled\n");
- last_complaint = jiffies;
- }
- }
- /* This requires some explaining. If DNAT has taken place,
- * we will need to fix up the destination Ethernet address,
- * and this is a tricky process.
- *
- * There are two cases to consider:
- * 1. The packet was DNAT'ed to a device in the same bridge
- * port group as it was received on. We can still bridge
- * the packet.
- * 2. The packet was DNAT'ed to a different device, either
- * a non-bridged device or another bridge port group.
- * The packet will need to be routed.
- *
- * The correct way of distinguishing between these two cases is to
- * call ip_route_input() and to look at skb->dst->dev, which is
- * changed to the destination device if ip_route_input() succeeds.
- *
- * Let us first consider the case that ip_route_input() succeeds:
- *
- * If skb->dst->dev equals the logical bridge device the packet
- * came in on, we can consider this bridging. We then call
- * skb->dst->output() which will make the packet enter br_nf_local_out()
- * not much later. In that function it is assured that the iptables
- * FORWARD chain is traversed for the packet.
- *
- * Otherwise, the packet is considered to be routed and we just
- * change the destination MAC address so that the packet will
- * later be passed up to the IP stack to be routed. For a redirected
- * packet, ip_route_input() will give back the localhost as output device,
- * which differs from the bridge device.
- *
- * Let us now consider the case that ip_route_input() fails:
- *
- * This can be because the destination address is martian, in which case
- * the packet will be dropped.
- * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input()
- * will fail, while __ip_route_output_key() will return success. The source
- * address for __ip_route_output_key() is set to zero, so __ip_route_output_key
- * thinks we're handling a locally generated packet and won't care
- * if IP forwarding is allowed. We send a warning message to the users's
- * log telling her to put IP forwarding on.
- *
- * ip_route_input() will also fail if there is no route available.
- * In that case we just drop the packet.
- *
- * --Lennert, 20020411
- * --Bart, 20020416 (updated)
- * --Bart, 20021007 (updated)
- * --Bart, 20062711 (updated) */
- static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
- {
- if (skb->pkt_type == PACKET_OTHERHOST) {
- skb->pkt_type = PACKET_HOST;
- skb->nf_bridge->mask |= BRNF_PKT_TYPE;
- }
- skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
- skb->dev = bridge_parent(skb->dev);
- if (!skb->dev)
- kfree_skb(skb);
- else {
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_pull(skb, VLAN_HLEN);
- skb->nh.raw += VLAN_HLEN;
- }
- skb->dst->output(skb);
- }
- return 0;
- }
- static int br_nf_pre_routing_finish(struct sk_buff *skb)
- {
- struct net_device *dev = skb->dev;
- struct iphdr *iph = skb->nh.iph;
- struct nf_bridge_info *nf_bridge = skb->nf_bridge;
- int err;
- if (nf_bridge->mask & BRNF_PKT_TYPE) {
- skb->pkt_type = PACKET_OTHERHOST;
- nf_bridge->mask ^= BRNF_PKT_TYPE;
- }
- nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
- if (dnat_took_place(skb)) {
- if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
- struct rtable *rt;
- struct flowi fl = {
- .nl_u = {
- .ip4_u = {
- .daddr = iph->daddr,
- .saddr = 0,
- .tos = RT_TOS(iph->tos) },
- },
- .proto = 0,
- };
- struct in_device *in_dev = in_dev_get(dev);
- /* If err equals -EHOSTUNREACH the error is due to a
- * martian destination or due to the fact that
- * forwarding is disabled. For most martian packets,
- * ip_route_output_key() will fail. It won't fail for 2 types of
- * martian destinations: loopback destinations and destination
- * 0.0.0.0. In both cases the packet will be dropped because the
- * destination is the loopback device and not the bridge. */
- if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
- goto free_skb;
- if (!ip_route_output_key(&rt, &fl)) {
- /* - Bridged-and-DNAT'ed traffic doesn't
- * require ip_forwarding. */
- if (((struct dst_entry *)rt)->dev == dev) {
- skb->dst = (struct dst_entry *)rt;
- goto bridged_dnat;
- }
- /* we are sure that forwarding is disabled, so printing
- * this message is no problem. Note that the packet could
- * still have a martian destination address, in which case
- * the packet could be dropped even if forwarding were enabled */
- __br_dnat_complain();
- dst_release((struct dst_entry *)rt);
- }
- free_skb:
- kfree_skb(skb);
- return 0;
- } else {
- if (skb->dst->dev == dev) {
- bridged_dnat:
- /* Tell br_nf_local_out this is a
- * bridged frame */
- nf_bridge->mask |= BRNF_BRIDGED_DNAT;
- skb->dev = nf_bridge->physindev;
- if (skb->protocol ==
- htons(ETH_P_8021Q)) {
- skb_push(skb, VLAN_HLEN);
- skb->nh.raw -= VLAN_HLEN;
- }
- NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
- skb, skb->dev, NULL,
- br_nf_pre_routing_finish_bridge,
- 1);
- return 0;
- }
- memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
- skb->pkt_type = PACKET_HOST;
- }
- } else {
- skb->dst = (struct dst_entry *)&__fake_rtable;
- dst_hold(skb->dst);
- }
- skb->dev = nf_bridge->physindev;
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_push(skb, VLAN_HLEN);
- skb->nh.raw -= VLAN_HLEN;
- }
- NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
- br_handle_frame_finish, 1);
- return 0;
- }
- /* Some common code for IPv4/IPv6 */
- static struct net_device *setup_pre_routing(struct sk_buff *skb)
- {
- struct nf_bridge_info *nf_bridge = skb->nf_bridge;
- if (skb->pkt_type == PACKET_OTHERHOST) {
- skb->pkt_type = PACKET_HOST;
- nf_bridge->mask |= BRNF_PKT_TYPE;
- }
- nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
- nf_bridge->physindev = skb->dev;
- skb->dev = bridge_parent(skb->dev);
- return skb->dev;
- }
- /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
- static int check_hbh_len(struct sk_buff *skb)
- {
- unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
- u32 pkt_len;
- int off = raw - skb->nh.raw;
- int len = (raw[1] + 1) << 3;
- if ((raw + len) - skb->data > skb_headlen(skb))
- goto bad;
- off += 2;
- len -= 2;
- while (len > 0) {
- int optlen = skb->nh.raw[off + 1] + 2;
- switch (skb->nh.raw[off]) {
- case IPV6_TLV_PAD0:
- optlen = 1;
- break;
- case IPV6_TLV_PADN:
- break;
- case IPV6_TLV_JUMBO:
- if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
- goto bad;
- pkt_len = ntohl(*(__be32 *) (skb->nh.raw + off + 2));
- if (pkt_len <= IPV6_MAXPLEN ||
- skb->nh.ipv6h->payload_len)
- goto bad;
- if (pkt_len > skb->len - sizeof(struct ipv6hdr))
- goto bad;
- if (pskb_trim_rcsum(skb,
- pkt_len + sizeof(struct ipv6hdr)))
- goto bad;
- 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 = skb->nh.ipv6h;
- 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_IP6_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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- struct iphdr *iph;
- __u32 len;
- struct sk_buff *skb = *pskb;
- if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
- #ifdef CONFIG_SYSCTL
- if (!brnf_call_ip6tables)
- return NF_ACCEPT;
- #endif
- if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
- goto out;
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_pull_rcsum(skb, VLAN_HLEN);
- skb->nh.raw += VLAN_HLEN;
- }
- 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))
- return NF_ACCEPT;
- if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
- goto out;
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_pull_rcsum(skb, VLAN_HLEN);
- skb->nh.raw += VLAN_HLEN;
- }
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
- goto inhdr_error;
- iph = skb->nh.iph;
- if (iph->ihl < 5 || iph->version != 4)
- goto inhdr_error;
- if (!pskb_may_pull(skb, 4 * iph->ihl))
- goto inhdr_error;
- iph = skb->nh.iph;
- 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_IP_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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- struct sk_buff *skb = *pskb;
- if (skb->dst == (struct dst_entry *)&__fake_rtable) {
- dst_release(skb->dst);
- skb->dst = 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));
- }
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_push(skb, VLAN_HLEN);
- skb->nh.raw -= VLAN_HLEN;
- }
- 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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- struct sk_buff *skb = *pskb;
- struct nf_bridge_info *nf_bridge;
- struct net_device *parent;
- int pf;
- if (!skb->nf_bridge)
- return NF_ACCEPT;
- parent = bridge_parent(out);
- if (!parent)
- return NF_DROP;
- if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
- pf = PF_INET;
- else
- pf = PF_INET6;
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_pull(*pskb, VLAN_HLEN);
- (*pskb)->nh.raw += VLAN_HLEN;
- }
- 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_IP_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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- struct sk_buff *skb = *pskb;
- 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;
- skb_pull(*pskb, VLAN_HLEN);
- (*pskb)->nh.raw += VLAN_HLEN;
- }
- if (skb->nh.arph->ar_pln != 4) {
- if (IS_VLAN_ARP(skb)) {
- skb_push(*pskb, VLAN_HLEN);
- (*pskb)->nh.raw -= VLAN_HLEN;
- }
- 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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- struct net_device *realindev;
- struct sk_buff *skb = *pskb;
- struct nf_bridge_info *nf_bridge;
- if (!skb->nf_bridge)
- return NF_ACCEPT;
- 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;
- }
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_push(skb, VLAN_HLEN);
- skb->nh.raw -= VLAN_HLEN;
- }
- 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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- struct sk_buff *skb = *pskb;
- struct nf_bridge_info *nf_bridge = (*pskb)->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.raw < skb->head || skb->mac.raw + 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 (!realoutdev)
- return NF_DROP;
- if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_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;
- }
- if (skb->protocol == htons(ETH_P_8021Q)) {
- skb_pull(skb, VLAN_HLEN);
- skb->nh.raw += VLAN_HLEN;
- }
- nf_bridge_save_header(skb);
- #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
- if (nf_bridge->netoutdev)
- realoutdev = nf_bridge->netoutdev;
- #endif
- NF_HOOK(pf, NF_IP_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.raw,
- 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 **pskb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- if ((*pskb)->nf_bridge &&
- !((*pskb)->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[] = {
- { .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_IP_PRE_ROUTING,
- .priority = NF_IP_PRI_FIRST, },
- { .hook = ip_sabotage_in,
- .owner = THIS_MODULE,
- .pf = PF_INET6,
- .hooknum = NF_IP6_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[] = {
- {
- .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
- .procname = "bridge-nf-call-arptables",
- .data = &brnf_call_arptables,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &brnf_sysctl_call_tables,
- },
- {
- .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
- .procname = "bridge-nf-call-iptables",
- .data = &brnf_call_iptables,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &brnf_sysctl_call_tables,
- },
- {
- .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
- .procname = "bridge-nf-call-ip6tables",
- .data = &brnf_call_ip6tables,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &brnf_sysctl_call_tables,
- },
- {
- .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
- .procname = "bridge-nf-filter-vlan-tagged",
- .data = &brnf_filter_vlan_tagged,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &brnf_sysctl_call_tables,
- },
- { .ctl_name = 0 }
- };
- static ctl_table brnf_bridge_table[] = {
- {
- .ctl_name = NET_BRIDGE,
- .procname = "bridge",
- .mode = 0555,
- .child = brnf_table,
- },
- { .ctl_name = 0 }
- };
- static ctl_table brnf_net_table[] = {
- {
- .ctl_name = CTL_NET,
- .procname = "net",
- .mode = 0555,
- .child = brnf_bridge_table,
- },
- { .ctl_name = 0 }
- };
- #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_table(brnf_net_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
- }
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