| /* |
| * Handle firewalling |
| * Linux ethernet bridge |
| * |
| * Authors: |
| * Lennert Buytenhek <buytenh@gnu.org> |
| * Bart De Schuymer (maintainer) <bdschuym@pandora.be> |
| * |
| * Changes: |
| * Apr 29 2003: physdev module support (bdschuym) |
| * Jun 19 2003: let arptables see bridged ARP traffic (bdschuym) |
| * Oct 06 2003: filter encapsulated IP/ARP VLAN traffic on untagged bridge |
| * (bdschuym) |
| * Sep 01 2004: add IPv6 filtering (bdschuym) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Lennert dedicates this file to Kerstin Wurdinger. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/ip.h> |
| #include <linux/netdevice.h> |
| #include <linux/skbuff.h> |
| #include <linux/if_arp.h> |
| #include <linux/if_ether.h> |
| #include <linux/if_vlan.h> |
| #include <linux/netfilter_bridge.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/netfilter_ipv6.h> |
| #include <linux/netfilter_arp.h> |
| #include <linux/in_route.h> |
| |
| #include <net/ip.h> |
| #include <net/ipv6.h> |
| #include <net/route.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/checksum.h> |
| #include "br_private.h" |
| #ifdef CONFIG_SYSCTL |
| #include <linux/sysctl.h> |
| #endif |
| |
| #define skb_origaddr(skb) (((struct bridge_skb_cb *) \ |
| (skb->nf_bridge->data))->daddr.ipv4) |
| #define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr) |
| #define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr) |
| |
| #define has_bridge_parent(device) ((device)->br_port != NULL) |
| #define bridge_parent(device) ((device)->br_port->br->dev) |
| |
| #ifdef CONFIG_SYSCTL |
| static struct ctl_table_header *brnf_sysctl_header; |
| static int brnf_call_iptables = 1; |
| static int brnf_call_ip6tables = 1; |
| static int brnf_call_arptables = 1; |
| static int brnf_filter_vlan_tagged = 1; |
| #else |
| #define brnf_filter_vlan_tagged 1 |
| #endif |
| |
| #define IS_VLAN_IP (skb->protocol == __constant_htons(ETH_P_8021Q) && \ |
| hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IP) && \ |
| brnf_filter_vlan_tagged) |
| #define IS_VLAN_IPV6 (skb->protocol == __constant_htons(ETH_P_8021Q) && \ |
| hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IPV6) && \ |
| brnf_filter_vlan_tagged) |
| #define IS_VLAN_ARP (skb->protocol == __constant_htons(ETH_P_8021Q) && \ |
| hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_ARP) && \ |
| brnf_filter_vlan_tagged) |
| |
| /* We need these fake structures to make netfilter happy -- |
| * lots of places assume that skb->dst != NULL, which isn't |
| * all that unreasonable. |
| * |
| * Currently, we fill in the PMTU entry because netfilter |
| * refragmentation needs it, and the rt_flags entry because |
| * ipt_REJECT needs it. Future netfilter modules might |
| * require us to fill additional fields. */ |
| static struct net_device __fake_net_device = { |
| .hard_header_len = ETH_HLEN |
| }; |
| |
| static struct rtable __fake_rtable = { |
| .u = { |
| .dst = { |
| .__refcnt = ATOMIC_INIT(1), |
| .dev = &__fake_net_device, |
| .path = &__fake_rtable.u.dst, |
| .metrics = {[RTAX_MTU - 1] = 1500}, |
| } |
| }, |
| .rt_flags = 0, |
| }; |
| |
| |
| /* PF_BRIDGE/PRE_ROUTING *********************************************/ |
| /* Undo the changes made for ip6tables PREROUTING and continue the |
| * bridge PRE_ROUTING hook. */ |
| static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb) |
| { |
| struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
| |
| if (nf_bridge->mask & BRNF_PKT_TYPE) { |
| skb->pkt_type = PACKET_OTHERHOST; |
| nf_bridge->mask ^= BRNF_PKT_TYPE; |
| } |
| nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING; |
| |
| skb->dst = (struct dst_entry *)&__fake_rtable; |
| dst_hold(skb->dst); |
| |
| skb->dev = nf_bridge->physindev; |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_push(skb, VLAN_HLEN); |
| skb->nh.raw -= VLAN_HLEN; |
| } |
| NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
| br_handle_frame_finish, 1); |
| |
| return 0; |
| } |
| |
| static void __br_dnat_complain(void) |
| { |
| static unsigned long last_complaint; |
| |
| if (jiffies - last_complaint >= 5 * HZ) { |
| printk(KERN_WARNING "Performing cross-bridge DNAT requires IP " |
| "forwarding to be enabled\n"); |
| last_complaint = jiffies; |
| } |
| } |
| |
| /* This requires some explaining. If DNAT has taken place, |
| * we will need to fix up the destination Ethernet address, |
| * and this is a tricky process. |
| * |
| * There are two cases to consider: |
| * 1. The packet was DNAT'ed to a device in the same bridge |
| * port group as it was received on. We can still bridge |
| * the packet. |
| * 2. The packet was DNAT'ed to a different device, either |
| * a non-bridged device or another bridge port group. |
| * The packet will need to be routed. |
| * |
| * The correct way of distinguishing between these two cases is to |
| * call ip_route_input() and to look at skb->dst->dev, which is |
| * changed to the destination device if ip_route_input() succeeds. |
| * |
| * Let us first consider the case that ip_route_input() succeeds: |
| * |
| * If skb->dst->dev equals the logical bridge device the packet |
| * came in on, we can consider this bridging. We then call |
| * skb->dst->output() which will make the packet enter br_nf_local_out() |
| * not much later. In that function it is assured that the iptables |
| * FORWARD chain is traversed for the packet. |
| * |
| * Otherwise, the packet is considered to be routed and we just |
| * change the destination MAC address so that the packet will |
| * later be passed up to the IP stack to be routed. |
| * |
| * Let us now consider the case that ip_route_input() fails: |
| * |
| * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input() |
| * will fail, while __ip_route_output_key() will return success. The source |
| * address for __ip_route_output_key() is set to zero, so __ip_route_output_key |
| * thinks we're handling a locally generated packet and won't care |
| * if IP forwarding is allowed. We send a warning message to the users's |
| * log telling her to put IP forwarding on. |
| * |
| * ip_route_input() will also fail if there is no route available. |
| * In that case we just drop the packet. |
| * |
| * --Lennert, 20020411 |
| * --Bart, 20020416 (updated) |
| * --Bart, 20021007 (updated) */ |
| static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb) |
| { |
| if (skb->pkt_type == PACKET_OTHERHOST) { |
| skb->pkt_type = PACKET_HOST; |
| skb->nf_bridge->mask |= BRNF_PKT_TYPE; |
| } |
| skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING; |
| |
| skb->dev = bridge_parent(skb->dev); |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_pull(skb, VLAN_HLEN); |
| skb->nh.raw += VLAN_HLEN; |
| } |
| skb->dst->output(skb); |
| return 0; |
| } |
| |
| static int br_nf_pre_routing_finish(struct sk_buff *skb) |
| { |
| struct net_device *dev = skb->dev; |
| struct iphdr *iph = skb->nh.iph; |
| struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
| |
| 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 (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, |
| dev)) { |
| struct rtable *rt; |
| struct flowi fl = { .nl_u = |
| { .ip4_u = { .daddr = iph->daddr, .saddr = 0 , |
| .tos = RT_TOS(iph->tos)} }, .proto = 0}; |
| |
| if (!ip_route_output_key(&rt, &fl)) { |
| /* - Bridged-and-DNAT'ed traffic doesn't |
| * require ip_forwarding. |
| * - Deal with redirected traffic. */ |
| if (((struct dst_entry *)rt)->dev == dev || |
| rt->rt_type == RTN_LOCAL) { |
| skb->dst = (struct dst_entry *)rt; |
| goto bridged_dnat; |
| } |
| __br_dnat_complain(); |
| dst_release((struct dst_entry *)rt); |
| } |
| kfree_skb(skb); |
| return 0; |
| } else { |
| if (skb->dst->dev == dev) { |
| bridged_dnat: |
| /* Tell br_nf_local_out this is a |
| * bridged frame */ |
| nf_bridge->mask |= BRNF_BRIDGED_DNAT; |
| skb->dev = nf_bridge->physindev; |
| if (skb->protocol == |
| __constant_htons(ETH_P_8021Q)) { |
| skb_push(skb, VLAN_HLEN); |
| skb->nh.raw -= VLAN_HLEN; |
| } |
| NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, |
| skb, skb->dev, NULL, |
| br_nf_pre_routing_finish_bridge, |
| 1); |
| return 0; |
| } |
| memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, |
| ETH_ALEN); |
| skb->pkt_type = PACKET_HOST; |
| } |
| } else { |
| skb->dst = (struct dst_entry *)&__fake_rtable; |
| dst_hold(skb->dst); |
| } |
| |
| skb->dev = nf_bridge->physindev; |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_push(skb, VLAN_HLEN); |
| skb->nh.raw -= VLAN_HLEN; |
| } |
| NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
| br_handle_frame_finish, 1); |
| |
| return 0; |
| } |
| |
| /* Some common code for IPv4/IPv6 */ |
| static void 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); |
| } |
| |
| /* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */ |
| static int check_hbh_len(struct sk_buff *skb) |
| { |
| unsigned char *raw = (u8*)(skb->nh.ipv6h+1); |
| u32 pkt_len; |
| int off = raw - skb->nh.raw; |
| int len = (raw[1]+1)<<3; |
| |
| if ((raw + len) - skb->data > skb_headlen(skb)) |
| goto bad; |
| |
| off += 2; |
| len -= 2; |
| |
| while (len > 0) { |
| int optlen = skb->nh.raw[off+1]+2; |
| |
| switch (skb->nh.raw[off]) { |
| case IPV6_TLV_PAD0: |
| optlen = 1; |
| break; |
| |
| case IPV6_TLV_PADN: |
| break; |
| |
| case IPV6_TLV_JUMBO: |
| if (skb->nh.raw[off+1] != 4 || (off&3) != 2) |
| goto bad; |
| pkt_len = ntohl(*(u32*)(skb->nh.raw+off+2)); |
| if (pkt_len <= IPV6_MAXPLEN || |
| skb->nh.ipv6h->payload_len) |
| goto bad; |
| if (pkt_len > skb->len - sizeof(struct ipv6hdr)) |
| goto bad; |
| if (pskb_trim_rcsum(skb, |
| pkt_len+sizeof(struct ipv6hdr))) |
| goto bad; |
| break; |
| default: |
| if (optlen > len) |
| goto bad; |
| break; |
| } |
| off += optlen; |
| len -= optlen; |
| } |
| if (len == 0) |
| return 0; |
| bad: |
| return -1; |
| |
| } |
| |
| /* Replicate the checks that IPv6 does on packet reception and pass the packet |
| * to ip6tables, which doesn't support NAT, so things are fairly simple. */ |
| static unsigned int br_nf_pre_routing_ipv6(unsigned int hook, |
| struct sk_buff *skb, const struct net_device *in, |
| const struct net_device *out, int (*okfn)(struct sk_buff *)) |
| { |
| struct ipv6hdr *hdr; |
| u32 pkt_len; |
| struct nf_bridge_info *nf_bridge; |
| |
| if (skb->len < sizeof(struct ipv6hdr)) |
| goto inhdr_error; |
| |
| if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) |
| goto inhdr_error; |
| |
| hdr = skb->nh.ipv6h; |
| |
| if (hdr->version != 6) |
| goto inhdr_error; |
| |
| pkt_len = ntohs(hdr->payload_len); |
| |
| if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { |
| if (pkt_len + sizeof(struct ipv6hdr) > skb->len) |
| goto inhdr_error; |
| if (pkt_len + sizeof(struct ipv6hdr) < skb->len) { |
| if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr))) |
| goto inhdr_error; |
| if (skb->ip_summed == CHECKSUM_HW) |
| skb->ip_summed = CHECKSUM_NONE; |
| } |
| } |
| if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb)) |
| goto inhdr_error; |
| |
| nf_bridge_put(skb->nf_bridge); |
| if ((nf_bridge = nf_bridge_alloc(skb)) == NULL) |
| return NF_DROP; |
| setup_pre_routing(skb); |
| |
| NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL, |
| br_nf_pre_routing_finish_ipv6); |
| |
| return NF_STOLEN; |
| |
| inhdr_error: |
| return NF_DROP; |
| } |
| |
| /* Direct IPv6 traffic to br_nf_pre_routing_ipv6. |
| * Replicate the checks that IPv4 does on packet reception. |
| * Set skb->dev to the bridge device (i.e. parent of the |
| * receiving device) to make netfilter happy, the REDIRECT |
| * target in particular. Save the original destination IP |
| * address to be able to detect DNAT afterwards. */ |
| static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct iphdr *iph; |
| __u32 len; |
| struct sk_buff *skb = *pskb; |
| struct nf_bridge_info *nf_bridge; |
| struct vlan_ethhdr *hdr = vlan_eth_hdr(*pskb); |
| |
| if (skb->protocol == __constant_htons(ETH_P_IPV6) || IS_VLAN_IPV6) { |
| #ifdef CONFIG_SYSCTL |
| if (!brnf_call_ip6tables) |
| return NF_ACCEPT; |
| #endif |
| if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL) |
| goto out; |
| |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| u8 *vhdr = skb->data; |
| skb_pull(skb, VLAN_HLEN); |
| skb_postpull_rcsum(skb, vhdr, VLAN_HLEN); |
| skb->nh.raw += VLAN_HLEN; |
| } |
| return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn); |
| } |
| #ifdef CONFIG_SYSCTL |
| if (!brnf_call_iptables) |
| return NF_ACCEPT; |
| #endif |
| |
| if (skb->protocol != __constant_htons(ETH_P_IP) && !IS_VLAN_IP) |
| return NF_ACCEPT; |
| |
| if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL) |
| goto out; |
| |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| u8 *vhdr = skb->data; |
| skb_pull(skb, VLAN_HLEN); |
| skb_postpull_rcsum(skb, vhdr, VLAN_HLEN); |
| skb->nh.raw += VLAN_HLEN; |
| } |
| |
| if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
| goto inhdr_error; |
| |
| iph = skb->nh.iph; |
| if (iph->ihl < 5 || iph->version != 4) |
| goto inhdr_error; |
| |
| if (!pskb_may_pull(skb, 4*iph->ihl)) |
| goto inhdr_error; |
| |
| iph = skb->nh.iph; |
| if (ip_fast_csum((__u8 *)iph, iph->ihl) != 0) |
| goto inhdr_error; |
| |
| len = ntohs(iph->tot_len); |
| if (skb->len < len || len < 4*iph->ihl) |
| goto inhdr_error; |
| |
| if (skb->len > len) { |
| __pskb_trim(skb, len); |
| if (skb->ip_summed == CHECKSUM_HW) |
| skb->ip_summed = CHECKSUM_NONE; |
| } |
| |
| nf_bridge_put(skb->nf_bridge); |
| if ((nf_bridge = nf_bridge_alloc(skb)) == NULL) |
| return NF_DROP; |
| setup_pre_routing(skb); |
| store_orig_dstaddr(skb); |
| |
| NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL, |
| br_nf_pre_routing_finish); |
| |
| return NF_STOLEN; |
| |
| inhdr_error: |
| // IP_INC_STATS_BH(IpInHdrErrors); |
| out: |
| return NF_DROP; |
| } |
| |
| |
| /* PF_BRIDGE/LOCAL_IN ************************************************/ |
| /* The packet is locally destined, which requires a real |
| * dst_entry, so detach the fake one. On the way up, the |
| * packet would pass through PRE_ROUTING again (which already |
| * took place when the packet entered the bridge), but we |
| * register an IPv4 PRE_ROUTING 'sabotage' hook that will |
| * prevent this from happening. */ |
| static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct sk_buff *skb = *pskb; |
| |
| if (skb->dst == (struct dst_entry *)&__fake_rtable) { |
| dst_release(skb->dst); |
| skb->dst = NULL; |
| } |
| |
| return NF_ACCEPT; |
| } |
| |
| |
| /* PF_BRIDGE/FORWARD *************************************************/ |
| static int br_nf_forward_finish(struct sk_buff *skb) |
| { |
| struct nf_bridge_info *nf_bridge = skb->nf_bridge; |
| struct net_device *in; |
| struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); |
| |
| if (skb->protocol != __constant_htons(ETH_P_ARP) && !IS_VLAN_ARP) { |
| in = nf_bridge->physindev; |
| if (nf_bridge->mask & BRNF_PKT_TYPE) { |
| skb->pkt_type = PACKET_OTHERHOST; |
| nf_bridge->mask ^= BRNF_PKT_TYPE; |
| } |
| } else { |
| in = *((struct net_device **)(skb->cb)); |
| } |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_push(skb, VLAN_HLEN); |
| skb->nh.raw -= VLAN_HLEN; |
| } |
| NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in, |
| skb->dev, br_forward_finish, 1); |
| return 0; |
| } |
| |
| /* This is the 'purely bridged' case. For IP, we pass the packet to |
| * netfilter with indev and outdev set to the bridge device, |
| * but we are still able to filter on the 'real' indev/outdev |
| * because of the physdev module. For ARP, indev and outdev are the |
| * bridge ports. */ |
| static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct sk_buff *skb = *pskb; |
| struct nf_bridge_info *nf_bridge; |
| struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); |
| int pf; |
| |
| if (!skb->nf_bridge) |
| return NF_ACCEPT; |
| |
| if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP) |
| pf = PF_INET; |
| else |
| pf = PF_INET6; |
| |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_pull(*pskb, VLAN_HLEN); |
| (*pskb)->nh.raw += VLAN_HLEN; |
| } |
| |
| nf_bridge = skb->nf_bridge; |
| if (skb->pkt_type == PACKET_OTHERHOST) { |
| skb->pkt_type = PACKET_HOST; |
| nf_bridge->mask |= BRNF_PKT_TYPE; |
| } |
| |
| /* The physdev module checks on this */ |
| nf_bridge->mask |= BRNF_BRIDGED; |
| nf_bridge->physoutdev = skb->dev; |
| |
| NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), |
| bridge_parent(out), br_nf_forward_finish); |
| |
| return NF_STOLEN; |
| } |
| |
| static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct sk_buff *skb = *pskb; |
| struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); |
| struct net_device **d = (struct net_device **)(skb->cb); |
| |
| #ifdef CONFIG_SYSCTL |
| if (!brnf_call_arptables) |
| return NF_ACCEPT; |
| #endif |
| |
| if (skb->protocol != __constant_htons(ETH_P_ARP)) { |
| if (!IS_VLAN_ARP) |
| return NF_ACCEPT; |
| skb_pull(*pskb, VLAN_HLEN); |
| (*pskb)->nh.raw += VLAN_HLEN; |
| } |
| |
| if (skb->nh.arph->ar_pln != 4) { |
| if (IS_VLAN_ARP) { |
| skb_push(*pskb, VLAN_HLEN); |
| (*pskb)->nh.raw -= VLAN_HLEN; |
| } |
| return NF_ACCEPT; |
| } |
| *d = (struct net_device *)in; |
| NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in, |
| (struct net_device *)out, br_nf_forward_finish); |
| |
| return NF_STOLEN; |
| } |
| |
| |
| /* PF_BRIDGE/LOCAL_OUT ***********************************************/ |
| static int br_nf_local_out_finish(struct sk_buff *skb) |
| { |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_push(skb, VLAN_HLEN); |
| skb->nh.raw -= VLAN_HLEN; |
| } |
| |
| NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, |
| br_forward_finish, NF_BR_PRI_FIRST + 1); |
| |
| return 0; |
| } |
| |
| /* This function sees both locally originated IP packets and forwarded |
| * IP packets (in both cases the destination device is a bridge |
| * device). It also sees bridged-and-DNAT'ed packets. |
| * To be able to filter on the physical bridge devices (with the physdev |
| * module), we steal packets destined to a bridge device away from the |
| * PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later, |
| * when we have determined the real output device. This is done in here. |
| * |
| * If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged |
| * and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward() |
| * will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority |
| * NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor |
| * will be executed. |
| * Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched |
| * this packet before, and so the packet was locally originated. We fake |
| * the PF_INET/LOCAL_OUT hook. |
| * Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed, |
| * so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure |
| * even routed packets that didn't arrive on a bridge interface have their |
| * nf_bridge->physindev set. */ |
| static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct net_device *realindev, *realoutdev; |
| struct sk_buff *skb = *pskb; |
| struct nf_bridge_info *nf_bridge; |
| struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); |
| int pf; |
| |
| if (!skb->nf_bridge) |
| return NF_ACCEPT; |
| |
| if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP) |
| pf = PF_INET; |
| else |
| pf = PF_INET6; |
| |
| #ifdef CONFIG_NETFILTER_DEBUG |
| /* Sometimes we get packets with NULL ->dst here (for example, |
| * running a dhcp client daemon triggers this). This should now |
| * be fixed, but let's keep the check around. */ |
| if (skb->dst == NULL) { |
| printk(KERN_CRIT "br_netfilter: skb->dst == NULL."); |
| return NF_ACCEPT; |
| } |
| #endif |
| |
| nf_bridge = skb->nf_bridge; |
| nf_bridge->physoutdev = skb->dev; |
| realindev = nf_bridge->physindev; |
| |
| /* Bridged, take PF_BRIDGE/FORWARD. |
| * (see big note in front of br_nf_pre_routing_finish) */ |
| if (nf_bridge->mask & BRNF_BRIDGED_DNAT) { |
| if (nf_bridge->mask & BRNF_PKT_TYPE) { |
| skb->pkt_type = PACKET_OTHERHOST; |
| nf_bridge->mask ^= BRNF_PKT_TYPE; |
| } |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_push(skb, VLAN_HLEN); |
| skb->nh.raw -= VLAN_HLEN; |
| } |
| |
| NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev, |
| skb->dev, br_forward_finish); |
| goto out; |
| } |
| realoutdev = bridge_parent(skb->dev); |
| |
| #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE) |
| /* iptables should match -o br0.x */ |
| if (nf_bridge->netoutdev) |
| realoutdev = nf_bridge->netoutdev; |
| #endif |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_pull(skb, VLAN_HLEN); |
| (*pskb)->nh.raw += VLAN_HLEN; |
| } |
| /* IP forwarded traffic has a physindev, locally |
| * generated traffic hasn't. */ |
| if (realindev != NULL) { |
| if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT) && |
| has_bridge_parent(realindev)) |
| realindev = bridge_parent(realindev); |
| |
| NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev, |
| realoutdev, br_nf_local_out_finish, |
| NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1); |
| } else { |
| NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev, |
| realoutdev, br_nf_local_out_finish, |
| NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1); |
| } |
| |
| out: |
| return NF_STOLEN; |
| } |
| |
| |
| /* PF_BRIDGE/POST_ROUTING ********************************************/ |
| static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct sk_buff *skb = *pskb; |
| struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge; |
| struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); |
| struct net_device *realoutdev = bridge_parent(skb->dev); |
| int pf; |
| |
| #ifdef CONFIG_NETFILTER_DEBUG |
| /* Be very paranoid. This probably won't happen anymore, but let's |
| * keep the check just to be sure... */ |
| if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) { |
| printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: " |
| "bad mac.raw pointer."); |
| goto print_error; |
| } |
| #endif |
| |
| if (!nf_bridge) |
| return NF_ACCEPT; |
| |
| if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP) |
| pf = PF_INET; |
| else |
| pf = PF_INET6; |
| |
| #ifdef CONFIG_NETFILTER_DEBUG |
| if (skb->dst == NULL) { |
| printk(KERN_CRIT "br_netfilter: skb->dst == NULL."); |
| goto print_error; |
| } |
| #endif |
| |
| /* We assume any code from br_dev_queue_push_xmit onwards doesn't care |
| * about the value of skb->pkt_type. */ |
| if (skb->pkt_type == PACKET_OTHERHOST) { |
| skb->pkt_type = PACKET_HOST; |
| nf_bridge->mask |= BRNF_PKT_TYPE; |
| } |
| |
| if (skb->protocol == __constant_htons(ETH_P_8021Q)) { |
| skb_pull(skb, VLAN_HLEN); |
| skb->nh.raw += VLAN_HLEN; |
| } |
| |
| nf_bridge_save_header(skb); |
| |
| #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE) |
| if (nf_bridge->netoutdev) |
| realoutdev = nf_bridge->netoutdev; |
| #endif |
| NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev, |
| br_dev_queue_push_xmit); |
| |
| return NF_STOLEN; |
| |
| #ifdef CONFIG_NETFILTER_DEBUG |
| print_error: |
| if (skb->dev != NULL) { |
| printk("[%s]", skb->dev->name); |
| if (has_bridge_parent(skb->dev)) |
| printk("[%s]", bridge_parent(skb->dev)->name); |
| } |
| printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw, |
| skb->data); |
| return NF_ACCEPT; |
| #endif |
| } |
| |
| |
| /* IP/SABOTAGE *****************************************************/ |
| /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING |
| * for the second time. */ |
| static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| if ((*pskb)->nf_bridge && |
| !((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) { |
| return NF_STOP; |
| } |
| |
| return NF_ACCEPT; |
| } |
| |
| /* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT |
| * and PF_INET(6)/POST_ROUTING until we have done the forwarding |
| * decision in the bridge code and have determined nf_bridge->physoutdev. */ |
| static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb, |
| const struct net_device *in, const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct sk_buff *skb = *pskb; |
| |
| if ((out->hard_start_xmit == br_dev_xmit && |
| okfn != br_nf_forward_finish && |
| okfn != br_nf_local_out_finish && |
| okfn != br_dev_queue_push_xmit) |
| #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE) |
| || ((out->priv_flags & IFF_802_1Q_VLAN) && |
| VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit) |
| #endif |
| ) { |
| struct nf_bridge_info *nf_bridge; |
| |
| if (!skb->nf_bridge) { |
| #ifdef CONFIG_SYSCTL |
| /* This code is executed while in the IP(v6) stack, |
| the version should be 4 or 6. We can't use |
| skb->protocol because that isn't set on |
| PF_INET(6)/LOCAL_OUT. */ |
| struct iphdr *ip = skb->nh.iph; |
| |
| if (ip->version == 4 && !brnf_call_iptables) |
| return NF_ACCEPT; |
| else if (ip->version == 6 && !brnf_call_ip6tables) |
| return NF_ACCEPT; |
| #endif |
| if (hook == NF_IP_POST_ROUTING) |
| return NF_ACCEPT; |
| if (!nf_bridge_alloc(skb)) |
| return NF_DROP; |
| } |
| |
| nf_bridge = skb->nf_bridge; |
| |
| /* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we |
| * will need the indev then. For a brouter, the real indev |
| * can be a bridge port, so we make sure br_nf_local_out() |
| * doesn't use the bridge parent of the indev by using |
| * the BRNF_DONT_TAKE_PARENT mask. */ |
| if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) { |
| nf_bridge->mask |= BRNF_DONT_TAKE_PARENT; |
| nf_bridge->physindev = (struct net_device *)in; |
| } |
| #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE) |
| /* the iptables outdev is br0.x, not br0 */ |
| if (out->priv_flags & IFF_802_1Q_VLAN) |
| nf_bridge->netoutdev = (struct net_device *)out; |
| #endif |
| return NF_STOP; |
| } |
| |
| return NF_ACCEPT; |
| } |
| |
| /* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent |
| * PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input. |
| * For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because |
| * ip_refrag() can return NF_STOLEN. */ |
| static struct nf_hook_ops br_nf_ops[] = { |
| { .hook = br_nf_pre_routing, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_PRE_ROUTING, |
| .priority = NF_BR_PRI_BRNF, }, |
| { .hook = br_nf_local_in, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_LOCAL_IN, |
| .priority = NF_BR_PRI_BRNF, }, |
| { .hook = br_nf_forward_ip, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_FORWARD, |
| .priority = NF_BR_PRI_BRNF - 1, }, |
| { .hook = br_nf_forward_arp, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_FORWARD, |
| .priority = NF_BR_PRI_BRNF, }, |
| { .hook = br_nf_local_out, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_LOCAL_OUT, |
| .priority = NF_BR_PRI_FIRST, }, |
| { .hook = br_nf_post_routing, |
| .owner = THIS_MODULE, |
| .pf = PF_BRIDGE, |
| .hooknum = NF_BR_POST_ROUTING, |
| .priority = NF_BR_PRI_LAST, }, |
| { .hook = ip_sabotage_in, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_PRE_ROUTING, |
| .priority = NF_IP_PRI_FIRST, }, |
| { .hook = ip_sabotage_in, |
| .owner = THIS_MODULE, |
| .pf = PF_INET6, |
| .hooknum = NF_IP6_PRE_ROUTING, |
| .priority = NF_IP6_PRI_FIRST, }, |
| { .hook = ip_sabotage_out, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_FORWARD, |
| .priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, }, |
| { .hook = ip_sabotage_out, |
| .owner = THIS_MODULE, |
| .pf = PF_INET6, |
| .hooknum = NF_IP6_FORWARD, |
| .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, }, |
| { .hook = ip_sabotage_out, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_LOCAL_OUT, |
| .priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, }, |
| { .hook = ip_sabotage_out, |
| .owner = THIS_MODULE, |
| .pf = PF_INET6, |
| .hooknum = NF_IP6_LOCAL_OUT, |
| .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, }, |
| { .hook = ip_sabotage_out, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_POST_ROUTING, |
| .priority = NF_IP_PRI_FIRST, }, |
| { .hook = ip_sabotage_out, |
| .owner = THIS_MODULE, |
| .pf = PF_INET6, |
| .hooknum = NF_IP6_POST_ROUTING, |
| .priority = NF_IP6_PRI_FIRST, }, |
| }; |
| |
| #ifdef CONFIG_SYSCTL |
| static |
| int brnf_sysctl_call_tables(ctl_table *ctl, int write, struct file * filp, |
| void __user *buffer, size_t *lenp, loff_t *ppos) |
| { |
| int ret; |
| |
| ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos); |
| |
| if (write && *(int *)(ctl->data)) |
| *(int *)(ctl->data) = 1; |
| return ret; |
| } |
| |
| static ctl_table brnf_table[] = { |
| { |
| .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES, |
| .procname = "bridge-nf-call-arptables", |
| .data = &brnf_call_arptables, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = &brnf_sysctl_call_tables, |
| }, |
| { |
| .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES, |
| .procname = "bridge-nf-call-iptables", |
| .data = &brnf_call_iptables, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = &brnf_sysctl_call_tables, |
| }, |
| { |
| .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES, |
| .procname = "bridge-nf-call-ip6tables", |
| .data = &brnf_call_ip6tables, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = &brnf_sysctl_call_tables, |
| }, |
| { |
| .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED, |
| .procname = "bridge-nf-filter-vlan-tagged", |
| .data = &brnf_filter_vlan_tagged, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = &brnf_sysctl_call_tables, |
| }, |
| { .ctl_name = 0 } |
| }; |
| |
| static ctl_table brnf_bridge_table[] = { |
| { |
| .ctl_name = NET_BRIDGE, |
| .procname = "bridge", |
| .mode = 0555, |
| .child = brnf_table, |
| }, |
| { .ctl_name = 0 } |
| }; |
| |
| static ctl_table brnf_net_table[] = { |
| { |
| .ctl_name = CTL_NET, |
| .procname = "net", |
| .mode = 0555, |
| .child = brnf_bridge_table, |
| }, |
| { .ctl_name = 0 } |
| }; |
| #endif |
| |
| int br_netfilter_init(void) |
| { |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) { |
| int ret; |
| |
| if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0) |
| continue; |
| |
| while (i--) |
| nf_unregister_hook(&br_nf_ops[i]); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_SYSCTL |
| brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0); |
| if (brnf_sysctl_header == NULL) { |
| printk(KERN_WARNING "br_netfilter: can't register to sysctl.\n"); |
| for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) |
| nf_unregister_hook(&br_nf_ops[i]); |
| return -EFAULT; |
| } |
| #endif |
| |
| printk(KERN_NOTICE "Bridge firewalling registered\n"); |
| |
| return 0; |
| } |
| |
| void br_netfilter_fini(void) |
| { |
| int i; |
| |
| for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--) |
| nf_unregister_hook(&br_nf_ops[i]); |
| #ifdef CONFIG_SYSCTL |
| unregister_sysctl_table(brnf_sysctl_header); |
| #endif |
| } |