+++ /dev/null
-/*
- * Handle firewalling
- * Linux ethernet bridge
- *
- * Authors:
- * Lennert Buytenhek <buytenh@gnu.org>
- * Bart De Schuymer <bdschuym@pandora.be>
- *
- * 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/slab.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/if_pppox.h>
-#include <linux/ppp_defs.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/addrconf.h>
-#include <net/route.h>
-#include <net/netfilter/br_netfilter.h>
-
-#include <asm/uaccess.h>
-#include "br_private.h"
-#ifdef CONFIG_SYSCTL
-#include <linux/sysctl.h>
-#endif
-
-#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 = 0;
-static int brnf_filter_pppoe_tagged __read_mostly = 0;
-static int brnf_pass_vlan_indev __read_mostly = 0;
-#else
-#define brnf_call_iptables 1
-#define brnf_call_ip6tables 1
-#define brnf_call_arptables 1
-#define brnf_filter_vlan_tagged 0
-#define brnf_filter_pppoe_tagged 0
-#define brnf_pass_vlan_indev 0
-#endif
-
-#define IS_IP(skb) \
- (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
-
-#define IS_IPV6(skb) \
- (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
-
-#define IS_ARP(skb) \
- (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
-
-static inline __be16 vlan_proto(const struct sk_buff *skb)
-{
- if (skb_vlan_tag_present(skb))
- return skb->protocol;
- else if (skb->protocol == htons(ETH_P_8021Q))
- return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
- else
- return 0;
-}
-
-#define IS_VLAN_IP(skb) \
- (vlan_proto(skb) == htons(ETH_P_IP) && \
- brnf_filter_vlan_tagged)
-
-#define IS_VLAN_IPV6(skb) \
- (vlan_proto(skb) == htons(ETH_P_IPV6) && \
- brnf_filter_vlan_tagged)
-
-#define IS_VLAN_ARP(skb) \
- (vlan_proto(skb) == htons(ETH_P_ARP) && \
- brnf_filter_vlan_tagged)
-
-static inline __be16 pppoe_proto(const struct sk_buff *skb)
-{
- return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
- sizeof(struct pppoe_hdr)));
-}
-
-#define IS_PPPOE_IP(skb) \
- (skb->protocol == htons(ETH_P_PPP_SES) && \
- pppoe_proto(skb) == htons(PPP_IP) && \
- brnf_filter_pppoe_tagged)
-
-#define IS_PPPOE_IPV6(skb) \
- (skb->protocol == htons(ETH_P_PPP_SES) && \
- pppoe_proto(skb) == htons(PPP_IPV6) && \
- brnf_filter_pppoe_tagged)
-
-/* largest possible L2 header, see br_nf_dev_queue_xmit() */
-#define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
-
-#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
-struct brnf_frag_data {
- char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH];
- u8 encap_size;
- u8 size;
- u16 vlan_tci;
- __be16 vlan_proto;
-};
-
-static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage);
-#endif
-
-static struct nf_bridge_info *nf_bridge_info_get(const struct sk_buff *skb)
-{
- return skb->nf_bridge;
-}
-
-static void nf_bridge_info_free(struct sk_buff *skb)
-{
- if (skb->nf_bridge) {
- nf_bridge_put(skb->nf_bridge);
- skb->nf_bridge = NULL;
- }
-}
-
-static inline struct rtable *bridge_parent_rtable(const struct net_device *dev)
-{
- struct net_bridge_port *port;
-
- port = br_port_get_rcu(dev);
- return port ? &port->br->fake_rtable : NULL;
-}
-
-static inline struct net_device *bridge_parent(const struct net_device *dev)
-{
- struct net_bridge_port *port;
-
- port = br_port_get_rcu(dev);
- 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 struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
-{
- struct nf_bridge_info *nf_bridge = skb->nf_bridge;
-
- if (atomic_read(&nf_bridge->use) > 1) {
- struct nf_bridge_info *tmp = nf_bridge_alloc(skb);
-
- if (tmp) {
- memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info));
- atomic_set(&tmp->use, 1);
- }
- nf_bridge_put(nf_bridge);
- nf_bridge = tmp;
- }
- return nf_bridge;
-}
-
-static unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
-{
- switch (skb->protocol) {
- case __cpu_to_be16(ETH_P_8021Q):
- return VLAN_HLEN;
- case __cpu_to_be16(ETH_P_PPP_SES):
- return PPPOE_SES_HLEN;
- default:
- return 0;
- }
-}
-
-static inline void nf_bridge_push_encap_header(struct sk_buff *skb)
-{
- unsigned int len = nf_bridge_encap_header_len(skb);
-
- skb_push(skb, len);
- skb->network_header -= len;
-}
-
-static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
-{
- unsigned int len = nf_bridge_encap_header_len(skb);
-
- skb_pull(skb, len);
- skb->network_header += len;
-}
-
-static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
-{
- unsigned int len = nf_bridge_encap_header_len(skb);
-
- skb_pull_rcsum(skb, len);
- skb->network_header += len;
-}
-
-/* When handing a packet over to the IP layer
- * check whether we have a skb that is in the
- * expected format
- */
-
-static int br_validate_ipv4(struct sk_buff *skb)
-{
- const struct iphdr *iph;
- struct net_device *dev = skb->dev;
- u32 len;
-
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
- goto inhdr_error;
-
- iph = ip_hdr(skb);
-
- /* Basic sanity checks */
- if (iph->ihl < 5 || iph->version != 4)
- goto inhdr_error;
-
- if (!pskb_may_pull(skb, iph->ihl*4))
- goto inhdr_error;
-
- iph = ip_hdr(skb);
- if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
- goto inhdr_error;
-
- len = ntohs(iph->tot_len);
- if (skb->len < len) {
- IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INTRUNCATEDPKTS);
- goto drop;
- } else if (len < (iph->ihl*4))
- goto inhdr_error;
-
- if (pskb_trim_rcsum(skb, len)) {
- IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
- goto drop;
- }
-
- memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
- /* We should really parse IP options here but until
- * somebody who actually uses IP options complains to
- * us we'll just silently ignore the options because
- * we're lazy!
- */
- return 0;
-
-inhdr_error:
- IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
-drop:
- return -1;
-}
-
-/* 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 *)(ipv6_hdr(skb) + 1);
- u32 pkt_len;
- const unsigned char *nh = skb_network_header(skb);
- int off = raw - nh;
- 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 = nh[off + 1] + 2;
-
- switch (nh[off]) {
- case IPV6_TLV_PAD1:
- optlen = 1;
- break;
-
- case IPV6_TLV_PADN:
- break;
-
- case IPV6_TLV_JUMBO:
- if (nh[off + 1] != 4 || (off & 3) != 2)
- goto bad;
- pkt_len = ntohl(*(__be32 *)(nh + off + 2));
- if (pkt_len <= IPV6_MAXPLEN ||
- ipv6_hdr(skb)->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;
- 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;
-}
-
-/* Equivalent to br_validate_ipv4 for IPv6 */
-static int br_validate_ipv6(struct sk_buff *skb)
-{
- const struct ipv6hdr *hdr;
- struct net_device *dev = skb->dev;
- struct inet6_dev *idev = in6_dev_get(skb->dev);
- u32 pkt_len;
- u8 ip6h_len = sizeof(struct ipv6hdr);
-
- if (!pskb_may_pull(skb, ip6h_len))
- goto inhdr_error;
-
- if (skb->len < ip6h_len)
- goto drop;
-
- 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 + ip6h_len > skb->len) {
- IP6_INC_STATS_BH(dev_net(dev), idev,
- IPSTATS_MIB_INTRUNCATEDPKTS);
- goto drop;
- }
- if (pskb_trim_rcsum(skb, pkt_len + ip6h_len)) {
- IP6_INC_STATS_BH(dev_net(dev), idev,
- IPSTATS_MIB_INDISCARDS);
- goto drop;
- }
- }
- if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
- goto drop;
-
- memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
- /* No IP options in IPv6 header; however it should be
- * checked if some next headers need special treatment
- */
- return 0;
-
-inhdr_error:
- IP6_INC_STATS_BH(dev_net(dev), idev, IPSTATS_MIB_INHDRERRORS);
-drop:
- return -1;
-}
-
-static void nf_bridge_update_protocol(struct sk_buff *skb)
-{
- switch (skb->nf_bridge->orig_proto) {
- case BRNF_PROTO_8021Q:
- skb->protocol = htons(ETH_P_8021Q);
- break;
- case BRNF_PROTO_PPPOE:
- skb->protocol = htons(ETH_P_PPP_SES);
- break;
- case BRNF_PROTO_UNCHANGED:
- break;
- }
-}
-
-/* Obtain the correct destination MAC address, while preserving the original
- * source MAC address. If we already know this address, we just copy it. If we
- * don't, we use the neighbour framework to find out. In both cases, we make
- * sure that br_handle_frame_finish() is called afterwards.
- */
-static int br_nf_pre_routing_finish_bridge(struct sock *sk, struct sk_buff *skb)
-{
- struct neighbour *neigh;
- struct dst_entry *dst;
-
- skb->dev = bridge_parent(skb->dev);
- if (!skb->dev)
- goto free_skb;
- dst = skb_dst(skb);
- neigh = dst_neigh_lookup_skb(dst, skb);
- if (neigh) {
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
- int ret;
-
- if (neigh->hh.hh_len) {
- neigh_hh_bridge(&neigh->hh, skb);
- skb->dev = nf_bridge->physindev;
- ret = br_handle_frame_finish(sk, skb);
- } else {
- /* the neighbour function below overwrites the complete
- * MAC header, so we save the Ethernet source address and
- * protocol number.
- */
- skb_copy_from_linear_data_offset(skb,
- -(ETH_HLEN-ETH_ALEN),
- nf_bridge->neigh_header,
- ETH_HLEN-ETH_ALEN);
- /* tell br_dev_xmit to continue with forwarding */
- nf_bridge->mask |= BRNF_BRIDGED_DNAT;
- /* FIXME Need to refragment */
- ret = neigh->output(neigh, skb);
- }
- neigh_release(neigh);
- return ret;
- }
-free_skb:
- kfree_skb(skb);
- return 0;
-}
-
-static bool daddr_was_changed(const struct sk_buff *skb,
- const struct nf_bridge_info *nf_bridge)
-{
- switch (skb->protocol) {
- case htons(ETH_P_IP):
- return ip_hdr(skb)->daddr != nf_bridge->ipv4_daddr;
- case htons(ETH_P_IPV6):
- return memcmp(&nf_bridge->ipv6_daddr, &ipv6_hdr(skb)->daddr,
- sizeof(ipv6_hdr(skb)->daddr)) != 0;
- default:
- return false;
- }
-}
-
-/* PF_BRIDGE/PRE_ROUTING: Undo the changes made for ip6tables
- * PREROUTING and continue the bridge PRE_ROUTING hook. See comment
- * for br_nf_pre_routing_finish(), same logic is used here but
- * equivalent IPv6 function ip6_route_input() called indirectly.
- */
-static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb)
-{
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
- struct rtable *rt;
- struct net_device *dev = skb->dev;
- const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
-
- nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
-
- if (nf_bridge->pkt_otherhost) {
- skb->pkt_type = PACKET_OTHERHOST;
- nf_bridge->pkt_otherhost = false;
- }
- nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING;
- if (daddr_was_changed(skb, nf_bridge)) {
- skb_dst_drop(skb);
- v6ops->route_input(skb);
-
- if (skb_dst(skb)->error) {
- kfree_skb(skb);
- return 0;
- }
-
- if (skb_dst(skb)->dev == dev) {
- skb->dev = nf_bridge->physindev;
- nf_bridge_update_protocol(skb);
- nf_bridge_push_encap_header(skb);
- NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
- sk, skb, skb->dev, NULL,
- br_nf_pre_routing_finish_bridge,
- 1);
- return 0;
- }
- ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
- skb->pkt_type = PACKET_HOST;
- } else {
- rt = bridge_parent_rtable(nf_bridge->physindev);
- if (!rt) {
- kfree_skb(skb);
- return 0;
- }
- skb_dst_set_noref(skb, &rt->dst);
- }
-
- skb->dev = nf_bridge->physindev;
- nf_bridge_update_protocol(skb);
- nf_bridge_push_encap_header(skb);
- NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb,
- skb->dev, NULL,
- br_handle_frame_finish, 1);
-
- return 0;
-}
-
-/* This requires some explaining. If DNAT has taken place,
- * we will need to fix up the destination Ethernet address.
- * This is also true when SNAT takes place (for the reply direction).
- *
- * 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's first consider the case that ip_route_input() succeeds:
- *
- * If the output device equals the logical bridge device the packet
- * came in on, we can consider this bridging. The corresponding MAC
- * address will be obtained in br_nf_pre_routing_finish_bridge.
- * 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's 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.
- * If IP forwarding is disabled, ip_route_input() will fail, while
- * ip_route_output_key() can 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 enabled. If the output device equals the logical bridge
- * device, we proceed as if ip_route_input() succeeded. If it differs from the
- * logical bridge port or if ip_route_output_key() fails we drop the packet.
- */
-static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
-{
- struct net_device *dev = skb->dev;
- struct iphdr *iph = ip_hdr(skb);
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
- struct rtable *rt;
- int err;
-
- nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
-
- if (nf_bridge->pkt_otherhost) {
- skb->pkt_type = PACKET_OTHERHOST;
- nf_bridge->pkt_otherhost = false;
- }
- nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING;
- if (daddr_was_changed(skb, nf_bridge)) {
- if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
- struct in_device *in_dev = __in_dev_get_rcu(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;
-
- rt = ip_route_output(dev_net(dev), iph->daddr, 0,
- RT_TOS(iph->tos), 0);
- if (!IS_ERR(rt)) {
- /* - Bridged-and-DNAT'ed traffic doesn't
- * require ip_forwarding. */
- if (rt->dst.dev == dev) {
- skb_dst_set(skb, &rt->dst);
- goto bridged_dnat;
- }
- ip_rt_put(rt);
- }
-free_skb:
- kfree_skb(skb);
- return 0;
- } else {
- if (skb_dst(skb)->dev == dev) {
-bridged_dnat:
- skb->dev = nf_bridge->physindev;
- nf_bridge_update_protocol(skb);
- nf_bridge_push_encap_header(skb);
- NF_HOOK_THRESH(NFPROTO_BRIDGE,
- NF_BR_PRE_ROUTING,
- sk, skb, skb->dev, NULL,
- br_nf_pre_routing_finish_bridge,
- 1);
- return 0;
- }
- ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
- skb->pkt_type = PACKET_HOST;
- }
- } else {
- rt = bridge_parent_rtable(nf_bridge->physindev);
- if (!rt) {
- kfree_skb(skb);
- return 0;
- }
- skb_dst_set_noref(skb, &rt->dst);
- }
-
- skb->dev = nf_bridge->physindev;
- nf_bridge_update_protocol(skb);
- nf_bridge_push_encap_header(skb);
- NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb,
- skb->dev, NULL,
- br_handle_frame_finish, 1);
-
- return 0;
-}
-
-static struct net_device *brnf_get_logical_dev(struct sk_buff *skb, const struct net_device *dev)
-{
- struct net_device *vlan, *br;
-
- br = bridge_parent(dev);
- if (brnf_pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
- return br;
-
- vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
- skb_vlan_tag_get(skb) & VLAN_VID_MASK);
-
- return vlan ? vlan : br;
-}
-
-/* Some common code for IPv4/IPv6 */
-static struct net_device *setup_pre_routing(struct sk_buff *skb)
-{
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
-
- if (skb->pkt_type == PACKET_OTHERHOST) {
- skb->pkt_type = PACKET_HOST;
- nf_bridge->pkt_otherhost = true;
- }
-
- nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
- nf_bridge->physindev = skb->dev;
- skb->dev = brnf_get_logical_dev(skb, skb->dev);
-
- if (skb->protocol == htons(ETH_P_8021Q))
- nf_bridge->orig_proto = BRNF_PROTO_8021Q;
- else if (skb->protocol == htons(ETH_P_PPP_SES))
- nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
-
- /* Must drop socket now because of tproxy. */
- skb_orphan(skb);
- return skb->dev;
-}
-
-/* Replicate the checks that IPv6 does on packet reception and pass the packet
- * to ip6tables.
- */
-static unsigned int br_nf_pre_routing_ipv6(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- struct nf_bridge_info *nf_bridge;
-
- if (br_validate_ipv6(skb))
- return NF_DROP;
-
- nf_bridge_put(skb->nf_bridge);
- if (!nf_bridge_alloc(skb))
- return NF_DROP;
- if (!setup_pre_routing(skb))
- return NF_DROP;
-
- nf_bridge = nf_bridge_info_get(skb);
- nf_bridge->ipv6_daddr = ipv6_hdr(skb)->daddr;
-
- skb->protocol = htons(ETH_P_IPV6);
- NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->sk, skb,
- skb->dev, NULL,
- br_nf_pre_routing_finish_ipv6);
-
- return NF_STOLEN;
-}
-
-/* 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(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- struct nf_bridge_info *nf_bridge;
- struct net_bridge_port *p;
- struct net_bridge *br;
- __u32 len = nf_bridge_encap_header_len(skb);
-
- if (unlikely(!pskb_may_pull(skb, len)))
- return NF_DROP;
-
- p = br_port_get_rcu(state->in);
- if (p == NULL)
- return NF_DROP;
- br = p->br;
-
- if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb)) {
- if (!brnf_call_ip6tables && !br->nf_call_ip6tables)
- return NF_ACCEPT;
-
- nf_bridge_pull_encap_header_rcsum(skb);
- return br_nf_pre_routing_ipv6(ops, skb, state);
- }
-
- if (!brnf_call_iptables && !br->nf_call_iptables)
- return NF_ACCEPT;
-
- if (!IS_IP(skb) && !IS_VLAN_IP(skb) && !IS_PPPOE_IP(skb))
- return NF_ACCEPT;
-
- nf_bridge_pull_encap_header_rcsum(skb);
-
- if (br_validate_ipv4(skb))
- return NF_DROP;
-
- nf_bridge_put(skb->nf_bridge);
- if (!nf_bridge_alloc(skb))
- return NF_DROP;
- if (!setup_pre_routing(skb))
- return NF_DROP;
-
- nf_bridge = nf_bridge_info_get(skb);
- nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
-
- skb->protocol = htons(ETH_P_IP);
-
- NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->sk, skb,
- skb->dev, NULL,
- br_nf_pre_routing_finish);
-
- return NF_STOLEN;
-}
-
-
-/* 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(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- br_drop_fake_rtable(skb);
- return NF_ACCEPT;
-}
-
-/* PF_BRIDGE/FORWARD *************************************************/
-static int br_nf_forward_finish(struct sock *sk, struct sk_buff *skb)
-{
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
- struct net_device *in;
-
- if (!IS_ARP(skb) && !IS_VLAN_ARP(skb)) {
-
- if (skb->protocol == htons(ETH_P_IP))
- nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
-
- if (skb->protocol == htons(ETH_P_IPV6))
- nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
-
- in = nf_bridge->physindev;
- if (nf_bridge->pkt_otherhost) {
- skb->pkt_type = PACKET_OTHERHOST;
- nf_bridge->pkt_otherhost = false;
- }
- nf_bridge_update_protocol(skb);
- } else {
- in = *((struct net_device **)(skb->cb));
- }
- nf_bridge_push_encap_header(skb);
-
- NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_FORWARD, sk, 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(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- struct nf_bridge_info *nf_bridge;
- struct net_device *parent;
- u_int8_t 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;
-
- nf_bridge = nf_bridge_info_get(skb);
- if (!nf_bridge)
- return NF_DROP;
-
- parent = bridge_parent(state->out);
- if (!parent)
- return NF_DROP;
-
- if (IS_IP(skb) || IS_VLAN_IP(skb) || IS_PPPOE_IP(skb))
- pf = NFPROTO_IPV4;
- else if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb))
- pf = NFPROTO_IPV6;
- else
- return NF_ACCEPT;
-
- nf_bridge_pull_encap_header(skb);
-
- if (skb->pkt_type == PACKET_OTHERHOST) {
- skb->pkt_type = PACKET_HOST;
- nf_bridge->pkt_otherhost = true;
- }
-
- if (pf == NFPROTO_IPV4) {
- if (br_validate_ipv4(skb))
- return NF_DROP;
- IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
- }
-
- if (pf == NFPROTO_IPV6) {
- if (br_validate_ipv6(skb))
- return NF_DROP;
- IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
- }
-
- nf_bridge->physoutdev = skb->dev;
- if (pf == NFPROTO_IPV4)
- skb->protocol = htons(ETH_P_IP);
- else
- skb->protocol = htons(ETH_P_IPV6);
-
- NF_HOOK(pf, NF_INET_FORWARD, NULL, skb,
- brnf_get_logical_dev(skb, state->in),
- parent, br_nf_forward_finish);
-
- return NF_STOLEN;
-}
-
-static unsigned int br_nf_forward_arp(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- struct net_bridge_port *p;
- struct net_bridge *br;
- struct net_device **d = (struct net_device **)(skb->cb);
-
- p = br_port_get_rcu(state->out);
- if (p == NULL)
- return NF_ACCEPT;
- br = p->br;
-
- if (!brnf_call_arptables && !br->nf_call_arptables)
- return NF_ACCEPT;
-
- if (!IS_ARP(skb)) {
- 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 = state->in;
- NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->sk, skb,
- state->in, state->out, br_nf_forward_finish);
-
- return NF_STOLEN;
-}
-
-#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) || IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
-static int br_nf_push_frag_xmit(struct sock *sk, struct sk_buff *skb)
-{
- struct brnf_frag_data *data;
- int err;
-
- data = this_cpu_ptr(&brnf_frag_data_storage);
- err = skb_cow_head(skb, data->size);
-
- if (err) {
- kfree_skb(skb);
- return 0;
- }
-
- if (data->vlan_tci) {
- skb->vlan_tci = data->vlan_tci;
- skb->vlan_proto = data->vlan_proto;
- }
-
- skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
- __skb_push(skb, data->encap_size);
-
- nf_bridge_info_free(skb);
- return br_dev_queue_push_xmit(sk, skb);
-}
-#endif
-
-static int br_nf_ip_fragment(struct sock *sk, struct sk_buff *skb,
- int (*output)(struct sock *, struct sk_buff *))
-{
- unsigned int mtu = ip_skb_dst_mtu(skb);
- struct iphdr *iph = ip_hdr(skb);
- struct rtable *rt = skb_rtable(skb);
- struct net_device *dev = rt->dst.dev;
-
- if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
- (IPCB(skb)->frag_max_size &&
- IPCB(skb)->frag_max_size > mtu))) {
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
- kfree_skb(skb);
- return -EMSGSIZE;
- }
-
- return ip_do_fragment(sk, skb, output);
-}
-
-static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
-{
- if (skb->nf_bridge->orig_proto == BRNF_PROTO_PPPOE)
- return PPPOE_SES_HLEN;
- return 0;
-}
-
-static int br_nf_dev_queue_xmit(struct sock *sk, struct sk_buff *skb)
-{
- struct nf_bridge_info *nf_bridge;
- unsigned int mtu_reserved;
-
- mtu_reserved = nf_bridge_mtu_reduction(skb);
-
- if (skb_is_gso(skb) || skb->len + mtu_reserved <= skb->dev->mtu) {
- nf_bridge_info_free(skb);
- return br_dev_queue_push_xmit(sk, skb);
- }
-
- nf_bridge = nf_bridge_info_get(skb);
-
-#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
- /* This is wrong! We should preserve the original fragment
- * boundaries by preserving frag_list rather than refragmenting.
- */
- if (skb->protocol == htons(ETH_P_IP)) {
- struct brnf_frag_data *data;
-
- if (br_validate_ipv4(skb))
- return NF_DROP;
-
- IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
-
- nf_bridge_update_protocol(skb);
-
- data = this_cpu_ptr(&brnf_frag_data_storage);
-
- data->vlan_tci = skb->vlan_tci;
- data->vlan_proto = skb->vlan_proto;
- data->encap_size = nf_bridge_encap_header_len(skb);
- data->size = ETH_HLEN + data->encap_size;
-
- skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
- data->size);
-
- return br_nf_ip_fragment(sk, skb, br_nf_push_frag_xmit);
- }
-#endif
-#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
- if (skb->protocol == htons(ETH_P_IPV6)) {
- const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
- struct brnf_frag_data *data;
-
- if (br_validate_ipv6(skb))
- return NF_DROP;
-
- IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
-
- nf_bridge_update_protocol(skb);
-
- data = this_cpu_ptr(&brnf_frag_data_storage);
- data->encap_size = nf_bridge_encap_header_len(skb);
- data->size = ETH_HLEN + data->encap_size;
-
- skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
- data->size);
-
- if (v6ops)
- return v6ops->fragment(sk, skb, br_nf_push_frag_xmit);
- else
- return -EMSGSIZE;
- }
-#endif
- nf_bridge_info_free(skb);
- return br_dev_queue_push_xmit(sk, skb);
-}
-
-/* PF_BRIDGE/POST_ROUTING ********************************************/
-static unsigned int br_nf_post_routing(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
- struct net_device *realoutdev = bridge_parent(skb->dev);
- u_int8_t pf;
-
- /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
- * on a bridge, but was delivered locally and is now being routed:
- *
- * POST_ROUTING was already invoked from the ip stack.
- */
- if (!nf_bridge || !nf_bridge->physoutdev)
- return NF_ACCEPT;
-
- if (!realoutdev)
- return NF_DROP;
-
- if (IS_IP(skb) || IS_VLAN_IP(skb) || IS_PPPOE_IP(skb))
- pf = NFPROTO_IPV4;
- else if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb))
- pf = NFPROTO_IPV6;
- else
- return NF_ACCEPT;
-
- /* 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->pkt_otherhost = true;
- }
-
- nf_bridge_pull_encap_header(skb);
- if (pf == NFPROTO_IPV4)
- skb->protocol = htons(ETH_P_IP);
- else
- skb->protocol = htons(ETH_P_IPV6);
-
- NF_HOOK(pf, NF_INET_POST_ROUTING, state->sk, skb,
- NULL, realoutdev,
- br_nf_dev_queue_xmit);
-
- return NF_STOLEN;
-}
-
-/* IP/SABOTAGE *****************************************************/
-/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
- * for the second time. */
-static unsigned int ip_sabotage_in(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- if (skb->nf_bridge &&
- !(skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
- return NF_STOP;
- }
-
- return NF_ACCEPT;
-}
-
-/* This is called when br_netfilter has called into iptables/netfilter,
- * and DNAT has taken place on a bridge-forwarded packet.
- *
- * neigh->output has created a new MAC header, with local br0 MAC
- * as saddr.
- *
- * This restores the original MAC saddr of the bridged packet
- * before invoking bridge forward logic to transmit the packet.
- */
-static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
-{
- struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
-
- skb_pull(skb, ETH_HLEN);
- nf_bridge->mask &= ~BRNF_BRIDGED_DNAT;
-
- BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
-
- skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
- nf_bridge->neigh_header,
- ETH_HLEN - ETH_ALEN);
- skb->dev = nf_bridge->physindev;
-
- nf_bridge->physoutdev = NULL;
- br_handle_frame_finish(NULL, skb);
-}
-
-static int br_nf_dev_xmit(struct sk_buff *skb)
-{
- if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
- br_nf_pre_routing_finish_bridge_slow(skb);
- return 1;
- }
- return 0;
-}
-
-static const struct nf_br_ops br_ops = {
- .br_dev_xmit_hook = br_nf_dev_xmit,
-};
-
-void br_netfilter_enable(void)
-{
-}
-EXPORT_SYMBOL_GPL(br_netfilter_enable);
-
-/* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
- * br_dev_queue_push_xmit is called afterwards */
-static struct nf_hook_ops br_nf_ops[] __read_mostly = {
- {
- .hook = br_nf_pre_routing,
- .owner = THIS_MODULE,
- .pf = NFPROTO_BRIDGE,
- .hooknum = NF_BR_PRE_ROUTING,
- .priority = NF_BR_PRI_BRNF,
- },
- {
- .hook = br_nf_local_in,
- .owner = THIS_MODULE,
- .pf = NFPROTO_BRIDGE,
- .hooknum = NF_BR_LOCAL_IN,
- .priority = NF_BR_PRI_BRNF,
- },
- {
- .hook = br_nf_forward_ip,
- .owner = THIS_MODULE,
- .pf = NFPROTO_BRIDGE,
- .hooknum = NF_BR_FORWARD,
- .priority = NF_BR_PRI_BRNF - 1,
- },
- {
- .hook = br_nf_forward_arp,
- .owner = THIS_MODULE,
- .pf = NFPROTO_BRIDGE,
- .hooknum = NF_BR_FORWARD,
- .priority = NF_BR_PRI_BRNF,
- },
- {
- .hook = br_nf_post_routing,
- .owner = THIS_MODULE,
- .pf = NFPROTO_BRIDGE,
- .hooknum = NF_BR_POST_ROUTING,
- .priority = NF_BR_PRI_LAST,
- },
- {
- .hook = ip_sabotage_in,
- .owner = THIS_MODULE,
- .pf = NFPROTO_IPV4,
- .hooknum = NF_INET_PRE_ROUTING,
- .priority = NF_IP_PRI_FIRST,
- },
- {
- .hook = ip_sabotage_in,
- .owner = THIS_MODULE,
- .pf = NFPROTO_IPV6,
- .hooknum = NF_INET_PRE_ROUTING,
- .priority = NF_IP6_PRI_FIRST,
- },
-};
-
-#ifdef CONFIG_SYSCTL
-static
-int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
-{
- int ret;
-
- ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
-
- if (write && *(int *)(ctl->data))
- *(int *)(ctl->data) = 1;
- return ret;
-}
-
-static struct 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,
- },
- {
- .procname = "bridge-nf-pass-vlan-input-dev",
- .data = &brnf_pass_vlan_indev,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = brnf_sysctl_call_tables,
- },
- { }
-};
-#endif
-
-static 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_net_sysctl(&init_net, "net/bridge", 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
- RCU_INIT_POINTER(nf_br_ops, &br_ops);
- printk(KERN_NOTICE "Bridge firewalling registered\n");
- return 0;
-}
-
-static void __exit br_netfilter_fini(void)
-{
- RCU_INIT_POINTER(nf_br_ops, NULL);
- nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
-#ifdef CONFIG_SYSCTL
- unregister_net_sysctl_table(brnf_sysctl_header);
-#endif
-}
-
-module_init(br_netfilter_init);
-module_exit(br_netfilter_fini);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
-MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
-MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");
git.samba.org / sfrench / cifs-2.6.git / blobdiff