| /* |
| * 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/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) = ip_hdr(skb)->daddr) |
| #define dnat_took_place(skb) (skb_origaddr(skb) != ip_hdr(skb)->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 = 0; |
| static int brnf_filter_pppoe_tagged __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 |
| #endif |
| |
| #define IS_IP(skb) \ |
| (!vlan_tx_tag_present(skb) && skb->protocol == htons(ETH_P_IP)) |
| |
| #define IS_IPV6(skb) \ |
| (!vlan_tx_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6)) |
| |
| #define IS_ARP(skb) \ |
| (!vlan_tx_tag_present(skb) && skb->protocol == htons(ETH_P_ARP)) |
| |
| static inline __be16 vlan_proto(const struct sk_buff *skb) |
| { |
| if (vlan_tx_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) |
| |
| static void fake_update_pmtu(struct dst_entry *dst, u32 mtu) |
| { |
| } |
| |
| static u32 *fake_cow_metrics(struct dst_entry *dst, unsigned long old) |
| { |
| return NULL; |
| } |
| |
| static struct neighbour *fake_neigh_lookup(const struct dst_entry *dst, const void *daddr) |
| { |
| return NULL; |
| } |
| |
| static unsigned int fake_mtu(const struct dst_entry *dst) |
| { |
| return dst->dev->mtu; |
| } |
| |
| static struct dst_ops fake_dst_ops = { |
| .family = AF_INET, |
| .protocol = cpu_to_be16(ETH_P_IP), |
| .update_pmtu = fake_update_pmtu, |
| .cow_metrics = fake_cow_metrics, |
| .neigh_lookup = fake_neigh_lookup, |
| .mtu = fake_mtu, |
| }; |
| |
| /* |
| * Initialize bogus route table used to keep netfilter happy. |
| * 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 const u32 br_dst_default_metrics[RTAX_MAX] = { |
| [RTAX_MTU - 1] = 1500, |
| }; |
| |
| void br_netfilter_rtable_init(struct net_bridge *br) |
| { |
| struct rtable *rt = &br->fake_rtable; |
| |
| atomic_set(&rt->dst.__refcnt, 1); |
| rt->dst.dev = br->dev; |
| rt->dst.path = &rt->dst; |
| dst_init_metrics(&rt->dst, br_dst_default_metrics, true); |
| rt->dst.flags = DST_NOXFRM | DST_NOPEER | DST_FAKE_RTABLE; |
| rt->dst.ops = &fake_dst_ops; |
| } |
| |
| 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 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; |
| } |
| |
| static inline void nf_bridge_save_header(struct sk_buff *skb) |
| { |
| int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb); |
| |
| skb_copy_from_linear_data_offset(skb, -header_size, |
| skb->nf_bridge->data, header_size); |
| } |
| |
| static inline void nf_bridge_update_protocol(struct sk_buff *skb) |
| { |
| if (skb->nf_bridge->mask & BRNF_8021Q) |
| skb->protocol = htons(ETH_P_8021Q); |
| else if (skb->nf_bridge->mask & BRNF_PPPoE) |
| skb->protocol = htons(ETH_P_PPP_SES); |
| } |
| |
| /* When handing a packet over to the IP layer |
| * check whether we have a skb that is in the |
| * expected format |
| */ |
| |
| static int br_parse_ip_options(struct sk_buff *skb) |
| { |
| struct ip_options *opt; |
| 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); |
| opt = &(IPCB(skb)->opt); |
| |
| /* 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)); |
| if (iph->ihl == 5) |
| return 0; |
| |
| opt->optlen = iph->ihl*4 - sizeof(struct iphdr); |
| if (ip_options_compile(dev_net(dev), opt, skb)) |
| goto inhdr_error; |
| |
| /* Check correct handling of SRR option */ |
| if (unlikely(opt->srr)) { |
| struct in_device *in_dev = __in_dev_get_rcu(dev); |
| if (in_dev && !IN_DEV_SOURCE_ROUTE(in_dev)) |
| goto drop; |
| |
| if (ip_options_rcv_srr(skb)) |
| goto drop; |
| } |
| |
| return 0; |
| |
| inhdr_error: |
| IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS); |
| drop: |
| return -1; |
| } |
| |
| /* Fill in the header for fragmented IP packets handled by |
| * the IPv4 connection tracking code. |
| */ |
| int nf_bridge_copy_header(struct sk_buff *skb) |
| { |
| int err; |
| unsigned int header_size; |
| |
| nf_bridge_update_protocol(skb); |
| header_size = ETH_HLEN + nf_bridge_encap_header_len(skb); |
| err = skb_cow_head(skb, header_size); |
| if (err) |
| return err; |
| |
| skb_copy_to_linear_data_offset(skb, -header_size, |
| skb->nf_bridge->data, header_size); |
| __skb_push(skb, nf_bridge_encap_header_len(skb)); |
| 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; |
| struct rtable *rt; |
| |
| 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; |
| |
| 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, skb, skb->dev, NULL, |
| br_handle_frame_finish, 1); |
| |
| return 0; |
| } |
| |
| /* 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 sk_buff *skb) |
| { |
| struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
| 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_get_neighbour_noref(dst); |
| if (neigh->hh.hh_len) { |
| neigh_hh_bridge(&neigh->hh, skb); |
| skb->dev = nf_bridge->physindev; |
| return br_handle_frame_finish(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), skb->nf_bridge->data, ETH_HLEN-ETH_ALEN); |
| /* tell br_dev_xmit to continue with forwarding */ |
| nf_bridge->mask |= BRNF_BRIDGED_DNAT; |
| return neigh->output(neigh, skb); |
| } |
| free_skb: |
| kfree_skb(skb); |
| return 0; |
| } |
| |
| /* This requires some explaining. If DNAT has taken place, |
| * we will need to fix up the destination Ethernet address. |
| * |
| * 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 sk_buff *skb) |
| { |
| struct net_device *dev = skb->dev; |
| struct iphdr *iph = ip_hdr(skb); |
| struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
| struct rtable *rt; |
| 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 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, |
| 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 { |
| 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, 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); |
| if (skb->protocol == htons(ETH_P_8021Q)) |
| nf_bridge->mask |= BRNF_8021Q; |
| else if (skb->protocol == htons(ETH_P_PPP_SES)) |
| nf_bridge->mask |= BRNF_PPPoE; |
| |
| 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 *)(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_PAD0: |
| 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; |
| |
| } |
| |
| /* 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 *)) |
| { |
| const struct ipv6hdr *hdr; |
| u32 pkt_len; |
| |
| if (skb->len < sizeof(struct ipv6hdr)) |
| return NF_DROP; |
| |
| if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) |
| return NF_DROP; |
| |
| hdr = ipv6_hdr(skb); |
| |
| if (hdr->version != 6) |
| return NF_DROP; |
| |
| pkt_len = ntohs(hdr->payload_len); |
| |
| if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { |
| if (pkt_len + sizeof(struct ipv6hdr) > skb->len) |
| return NF_DROP; |
| if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) |
| return NF_DROP; |
| } |
| if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(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; |
| |
| skb->protocol = htons(ETH_P_IPV6); |
| NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, 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(unsigned int hook, struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| 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(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(hook, skb, in, out, okfn); |
| } |
| |
| 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_parse_ip_options(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; |
| store_orig_dstaddr(skb); |
| skb->protocol = htons(ETH_P_IP); |
| |
| NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, 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(unsigned int hook, struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| br_drop_fake_rtable(skb); |
| 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 (!IS_ARP(skb) && !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; |
| } |
| 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, skb, in, |
| skb->dev, br_forward_finish, 1); |
| return 0; |
| } |
| |
| |
| /* This is the 'purely bridged' case. For IP, we pass the packet to |
| * netfilter with indev and outdev set to the bridge device, |
| * but we are still able to filter on the 'real' indev/outdev |
| * because of the physdev module. For ARP, indev and outdev are the |
| * bridge ports. */ |
| static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct nf_bridge_info *nf_bridge; |
| struct net_device *parent; |
| 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; |
| |
| parent = bridge_parent(out); |
| if (!parent) |
| return NF_DROP; |
| |
| if (IS_IP(skb) || IS_VLAN_IP(skb) || IS_PPPOE_IP(skb)) |
| pf = PF_INET; |
| else if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb)) |
| pf = PF_INET6; |
| else |
| return NF_ACCEPT; |
| |
| nf_bridge_pull_encap_header(skb); |
| |
| nf_bridge = skb->nf_bridge; |
| if (skb->pkt_type == PACKET_OTHERHOST) { |
| skb->pkt_type = PACKET_HOST; |
| nf_bridge->mask |= BRNF_PKT_TYPE; |
| } |
| |
| if (pf == PF_INET && br_parse_ip_options(skb)) |
| return NF_DROP; |
| |
| /* The physdev module checks on this */ |
| nf_bridge->mask |= BRNF_BRIDGED; |
| nf_bridge->physoutdev = skb->dev; |
| if (pf == PF_INET) |
| skb->protocol = htons(ETH_P_IP); |
| else |
| skb->protocol = htons(ETH_P_IPV6); |
| |
| NF_HOOK(pf, NF_INET_FORWARD, skb, bridge_parent(in), parent, |
| br_nf_forward_finish); |
| |
| return NF_STOLEN; |
| } |
| |
| static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct net_bridge_port *p; |
| struct net_bridge *br; |
| struct net_device **d = (struct net_device **)(skb->cb); |
| |
| p = br_port_get_rcu(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 = (struct net_device *)in; |
| NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in, |
| (struct net_device *)out, br_nf_forward_finish); |
| |
| return NF_STOLEN; |
| } |
| |
| #if IS_ENABLED(CONFIG_NF_CONNTRACK_IPV4) |
| static int br_nf_dev_queue_xmit(struct sk_buff *skb) |
| { |
| int ret; |
| |
| if (skb->nfct != NULL && skb->protocol == htons(ETH_P_IP) && |
| skb->len + nf_bridge_mtu_reduction(skb) > skb->dev->mtu && |
| !skb_is_gso(skb)) { |
| if (br_parse_ip_options(skb)) |
| /* Drop invalid packet */ |
| return NF_DROP; |
| ret = ip_fragment(skb, br_dev_queue_push_xmit); |
| } else |
| ret = br_dev_queue_push_xmit(skb); |
| |
| return ret; |
| } |
| #else |
| static int br_nf_dev_queue_xmit(struct sk_buff *skb) |
| { |
| return br_dev_queue_push_xmit(skb); |
| } |
| #endif |
| |
| /* PF_BRIDGE/POST_ROUTING ********************************************/ |
| static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
| struct net_device *realoutdev = bridge_parent(skb->dev); |
| u_int8_t pf; |
| |
| if (!nf_bridge || !(nf_bridge->mask & BRNF_BRIDGED)) |
| return NF_ACCEPT; |
| |
| if (!realoutdev) |
| return NF_DROP; |
| |
| if (IS_IP(skb) || IS_VLAN_IP(skb) || IS_PPPOE_IP(skb)) |
| pf = PF_INET; |
| else if (IS_IPV6(skb) || IS_VLAN_IPV6(skb) || IS_PPPOE_IPV6(skb)) |
| pf = PF_INET6; |
| 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->mask |= BRNF_PKT_TYPE; |
| } |
| |
| nf_bridge_pull_encap_header(skb); |
| nf_bridge_save_header(skb); |
| if (pf == PF_INET) |
| skb->protocol = htons(ETH_P_IP); |
| else |
| skb->protocol = htons(ETH_P_IPV6); |
| |
| NF_HOOK(pf, NF_INET_POST_ROUTING, 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(unsigned int hook, struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| if (skb->nf_bridge && |
| !(skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) { |
| return NF_STOP; |
| } |
| |
| return NF_ACCEPT; |
| } |
| |
| /* For br_nf_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 = 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_post_routing, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_POST_ROUTING, |
| .priority = NF_BR_PRI_LAST, |
| }, |
| { |
| .hook = ip_sabotage_in, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_INET_PRE_ROUTING, |
| .priority = NF_IP_PRI_FIRST, |
| }, |
| { |
| .hook = ip_sabotage_in, |
| .owner = THIS_MODULE, |
| .pf = PF_INET6, |
| .hooknum = NF_INET_PRE_ROUTING, |
| .priority = NF_IP6_PRI_FIRST, |
| }, |
| }; |
| |
| #ifdef CONFIG_SYSCTL |
| static |
| int brnf_sysctl_call_tables(ctl_table * ctl, int write, |
| 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 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, |
| }, |
| { } |
| }; |
| |
| static struct ctl_path brnf_path[] = { |
| { .procname = "net", }, |
| { .procname = "bridge", }, |
| { } |
| }; |
| #endif |
| |
| int __init br_netfilter_init(void) |
| { |
| int ret; |
| |
| ret = dst_entries_init(&fake_dst_ops); |
| if (ret < 0) |
| return ret; |
| |
| ret = nf_register_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops)); |
| if (ret < 0) { |
| dst_entries_destroy(&fake_dst_ops); |
| return ret; |
| } |
| #ifdef CONFIG_SYSCTL |
| brnf_sysctl_header = register_sysctl_paths(brnf_path, brnf_table); |
| if (brnf_sysctl_header == NULL) { |
| printk(KERN_WARNING |
| "br_netfilter: can't register to sysctl.\n"); |
| nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops)); |
| dst_entries_destroy(&fake_dst_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 |
| dst_entries_destroy(&fake_dst_ops); |
| } |