diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2015-06-16 13:38:26 +0200 |
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committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2015-06-18 13:05:53 +0200 |
commit | c4e70a87d975d1f561a00abfe2d3cefa2a486c95 (patch) | |
tree | 83b5129df118c623b6d9f3e2511c7347648ee4bc /net/bridge/br_netfilter.c | |
parent | a1a56aaa0735c7821e85c37268a7c12e132415cb (diff) | |
download | op-kernel-dev-c4e70a87d975d1f561a00abfe2d3cefa2a486c95.zip op-kernel-dev-c4e70a87d975d1f561a00abfe2d3cefa2a486c95.tar.gz |
netfilter: bridge: rename br_netfilter.c to br_netfilter_hooks.c
To prepare separation of the IPv6 code into different file.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/bridge/br_netfilter.c')
-rw-r--r-- | net/bridge/br_netfilter.c | 1282 |
1 files changed, 0 insertions, 1282 deletions
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c deleted file mode 100644 index e4e5f2f..0000000 --- a/net/bridge/br_netfilter.c +++ /dev/null @@ -1,1282 +0,0 @@ -/* - * 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"); |