Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 25 Oct 2002 01:53:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 25 Oct 2002 01:53:06 -0400 Received: from horkos.telenet-ops.be ([195.130.132.45]:6596 "EHLO horkos.telenet-ops.be") by vger.kernel.org with ESMTP id convert rfc822-to-8bit; Fri, 25 Oct 2002 01:52:47 -0400 Content-Type: text/plain; charset=US-ASCII From: Bart De Schuymer To: "David S. Miller" Subject: [PATCH][RFC] bridge-nf -- map IPv4 hooks onto bridge hooks - try 3, vs 2.5.44 Date: Fri, 25 Oct 2002 08:01:16 +0200 X-Mailer: KMail [version 1.4] Cc: linux-kernel@vger.kernel.org, Lennert Buytenhek , coreteam@netfilter.org References: <20020911223252.GA12517@erik.ca> <200210210020.37097.bart.de.schuymer@pandora.be> <200210230140.27470.bart.de.schuymer@pandora.be> In-Reply-To: <200210230140.27470.bart.de.schuymer@pandora.be> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <200210250801.16278.bart.de.schuymer@pandora.be> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 33311 Lines: 1092 Hello David, Harald, others, The following patch deals with the problems you still had with the earlier one. Changes: 1. add #if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) everywhere 2. don't touch ip_tables.c 3. no ipt_physdev.c file yet. I'll try to make it this weekend. As this ipt_physdev.c module is not essential I propose to already apply this patch. Harald, should I make this module for patch-o-magic or can I post it directly to David? The patch is also here: http://users.pandora.be/bart.de.schuymer/ebtables/br-nf/bridge-nf-0.0.10-dev-pre3-against-2.5.44.diff An incremental patch vs the previous one is here: http://users.pandora.be/bart.de.schuymer/ebtables/br-nf/bridge-nf-0.0.10-dev-pre3.001-against-2.5.44.diff cheers, Bart --- linux-2.5.44/include/linux/netfilter.h Sat Oct 19 06:01:54 2002 +++ linux-2.5.44-brnfpre3/include/linux/netfilter.h Thu Oct 24 18:32:34 2002 @@ -117,17 +117,23 @@ /* This is gross, but inline doesn't cut it for avoiding the function call in fast path: gcc doesn't inline (needs value tracking?). --RR */ #ifdef CONFIG_NETFILTER_DEBUG -#define NF_HOOK nf_hook_slow +#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ + nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn), INT_MIN) +#define NF_HOOK_THRESH nf_hook_slow #else #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ (list_empty(&nf_hooks[(pf)][(hook)]) \ ? (okfn)(skb) \ - : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn))) + : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn), INT_MIN)) +#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ +(list_empty(&nf_hooks[(pf)][(hook)]) \ + ? (okfn)(skb) \ + : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn), (thresh))) #endif int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, struct net_device *indev, struct net_device *outdev, - int (*okfn)(struct sk_buff *)); + int (*okfn)(struct sk_buff *), int thresh); /* Call setsockopt() */ int nf_setsockopt(struct sock *sk, int pf, int optval, char *opt, --- linux-2.5.44/include/linux/netfilter_ipv4.h Sat Oct 19 06:02:28 2002 +++ linux-2.5.44-brnfpre3/include/linux/netfilter_ipv4.h Thu Oct 24 18:32:34 2002 @@ -52,8 +52,10 @@ enum nf_ip_hook_priorities { NF_IP_PRI_FIRST = INT_MIN, NF_IP_PRI_CONNTRACK = -200, + NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD = -175, NF_IP_PRI_MANGLE = -150, NF_IP_PRI_NAT_DST = -100, + NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT = -50, NF_IP_PRI_FILTER = 0, NF_IP_PRI_NAT_SRC = 100, NF_IP_PRI_LAST = INT_MAX, --- linux-2.5.44/include/linux/netfilter_bridge.h Sat Oct 19 06:01:57 2002 +++ linux-2.5.44-brnfpre3/include/linux/netfilter_bridge.h Thu Oct 24 18:32:34 2002 @@ -6,6 +6,7 @@ #include #include +#include /* Bridge Hooks */ /* After promisc drops, checksum checks. */ @@ -22,14 +23,39 @@ #define NF_BR_BROUTING 5 #define NF_BR_NUMHOOKS 6 +#define BRNF_PKT_TYPE 0x01 +#define BRNF_BRIDGED_DNAT 0x02 +#define BRNF_DONT_TAKE_PARENT 0x04 + enum nf_br_hook_priorities { NF_BR_PRI_FIRST = INT_MIN, - NF_BR_PRI_FILTER_BRIDGED = -200, - NF_BR_PRI_FILTER_OTHER = 200, NF_BR_PRI_NAT_DST_BRIDGED = -300, + NF_BR_PRI_FILTER_BRIDGED = -200, + NF_BR_PRI_BRNF = 0, NF_BR_PRI_NAT_DST_OTHER = 100, + NF_BR_PRI_FILTER_OTHER = 200, NF_BR_PRI_NAT_SRC = 300, NF_BR_PRI_LAST = INT_MAX, +}; + +static inline +struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb) +{ + struct nf_bridge_info **nf_bridge = &(skb->nf_bridge); + + if ((*nf_bridge = kmalloc(sizeof(**nf_bridge), GFP_ATOMIC)) != NULL) { + atomic_set(&(*nf_bridge)->use, 1); + (*nf_bridge)->mask = 0; + (*nf_bridge)->physindev = (*nf_bridge)->physoutdev = NULL; + } + + return *nf_bridge; +} + +struct bridge_skb_cb { + union { + __u32 ipv4; + } daddr; }; #endif --- linux-2.5.44/include/linux/skbuff.h Sat Oct 19 06:01:58 2002 +++ linux-2.5.44-brnfpre3/include/linux/skbuff.h Thu Oct 24 18:32:34 2002 @@ -96,6 +96,17 @@ struct nf_ct_info { struct nf_conntrack *master; }; + +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) +struct nf_bridge_info { + atomic_t use; + struct net_device *physindev; + struct net_device *physoutdev; + unsigned int mask; + unsigned long hh[16 / sizeof(unsigned long)]; +}; +#endif + #endif struct sk_buff_head { @@ -166,6 +177,7 @@ * @nfcache: Cache info * @nfct: Associated connection, if any * @nf_debug: Netfilter debugging + * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c * @tc_index: Traffic control index */ @@ -236,6 +248,9 @@ #ifdef CONFIG_NETFILTER_DEBUG unsigned int nf_debug; #endif +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + struct nf_bridge_info *nf_bridge; +#endif #endif /* CONFIG_NETFILTER */ #if defined(CONFIG_HIPPI) union { @@ -1146,6 +1161,20 @@ if (nfct) atomic_inc(&nfct->master->use); } + +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) +static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge) +{ + if (nf_bridge && atomic_dec_and_test(&nf_bridge->use)) + kfree(nf_bridge); +} +static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge) +{ + if (nf_bridge) + atomic_inc(&nf_bridge->use); +} +#endif + #endif #endif /* __KERNEL__ */ --- linux-2.5.44/net/bridge/br.c Sat Oct 19 06:01:15 2002 +++ linux-2.5.44-brnfpre3/net/bridge/br.c Thu Oct 24 18:32:34 2002 @@ -45,6 +45,10 @@ { printk(KERN_INFO "NET4: Ethernet Bridge 008 for NET4.0\n"); +#ifdef CONFIG_NETFILTER + if (br_netfilter_init()) + return 1; +#endif br_handle_frame_hook = br_handle_frame; br_ioctl_hook = br_ioctl_deviceless_stub; #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE) @@ -63,6 +67,9 @@ static void __exit br_deinit(void) { +#ifdef CONFIG_NETFILTER + br_netfilter_fini(); +#endif unregister_netdevice_notifier(&br_device_notifier); br_call_ioctl_atomic(__br_clear_ioctl_hook); --- linux-2.5.44/net/bridge/br_forward.c Sat Oct 19 06:01:20 2002 +++ linux-2.5.44-brnfpre3/net/bridge/br_forward.c Thu Oct 24 18:32:34 2002 @@ -30,18 +30,23 @@ return 1; } -static int __dev_queue_push_xmit(struct sk_buff *skb) +int br_dev_queue_push_xmit(struct sk_buff *skb) { +#ifdef CONFIG_NETFILTER + if (skb->nf_bridge) + memcpy(skb->data - 16, skb->nf_bridge->hh, 16); +#endif skb_push(skb, ETH_HLEN); + dev_queue_xmit(skb); return 0; } -static int __br_forward_finish(struct sk_buff *skb) +int br_forward_finish(struct sk_buff *skb) { NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev, - __dev_queue_push_xmit); + br_dev_queue_push_xmit); return 0; } @@ -53,7 +58,7 @@ skb->nf_debug = 0; #endif NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, - __br_forward_finish); + br_forward_finish); } static void __br_forward(struct net_bridge_port *to, struct sk_buff *skb) @@ -64,7 +69,7 @@ skb->dev = to->dev; NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev, - __br_forward_finish); + br_forward_finish); } /* called under bridge lock */ --- linux-2.5.44/net/bridge/br_input.c Sat Oct 19 06:01:18 2002 +++ linux-2.5.44-brnfpre3/net/bridge/br_input.c Thu Oct 24 18:32:34 2002 @@ -49,7 +49,7 @@ br_pass_frame_up_finish); } -static int br_handle_frame_finish(struct sk_buff *skb) +int br_handle_frame_finish(struct sk_buff *skb) { struct net_bridge *br; unsigned char *dest; --- linux-2.5.44/net/bridge/br_private.h Sat Oct 19 06:01:18 2002 +++ linux-2.5.44-brnfpre3/net/bridge/br_private.h Thu Oct 24 18:32:34 2002 @@ -144,8 +144,10 @@ /* br_forward.c */ extern void br_deliver(struct net_bridge_port *to, struct sk_buff *skb); +extern int br_dev_queue_push_xmit(struct sk_buff *skb); extern void br_forward(struct net_bridge_port *to, struct sk_buff *skb); +extern int br_forward_finish(struct sk_buff *skb); extern void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone); @@ -166,6 +168,7 @@ int *ifindices); /* br_input.c */ +extern int br_handle_frame_finish(struct sk_buff *skb); extern int br_handle_frame(struct sk_buff *skb); /* br_ioctl.c */ @@ -176,6 +179,10 @@ unsigned long arg1, unsigned long arg2); extern int br_ioctl_deviceless_stub(unsigned long arg); + +/* br_netfilter.c */ +extern int br_netfilter_init(void); +extern void br_netfilter_fini(void); /* br_stp.c */ extern int br_is_root_bridge(struct net_bridge *br); --- linux-2.5.44/net/bridge/Makefile Sat Oct 19 06:02:32 2002 +++ linux-2.5.44-brnfpre3/net/bridge/Makefile Thu Oct 24 18:32:34 2002 @@ -9,6 +9,11 @@ bridge-objs := br.o br_device.o br_fdb.o br_forward.o br_if.o br_input.o \ br_ioctl.o br_notify.o br_stp.o br_stp_bpdu.o \ br_stp_if.o br_stp_timer.o + +ifeq ($(CONFIG_NETFILTER),y) +bridge-objs += br_netfilter.o +endif + obj-$(CONFIG_BRIDGE_NF_EBTABLES) += netfilter/ include $(TOPDIR)/Rules.make --- linux-2.5.44/net/core/netfilter.c Sat Oct 19 06:01:53 2002 +++ linux-2.5.44-brnfpre3/net/core/netfilter.c Thu Oct 24 18:32:34 2002 @@ -342,10 +342,15 @@ const struct net_device *indev, const struct net_device *outdev, struct list_head **i, - int (*okfn)(struct sk_buff *)) + int (*okfn)(struct sk_buff *), + int hook_thresh) { for (*i = (*i)->next; *i != head; *i = (*i)->next) { struct nf_hook_ops *elem = (struct nf_hook_ops *)*i; + + if (hook_thresh > elem->priority) + continue; + switch (elem->hook(hook, skb, indev, outdev, okfn)) { case NF_QUEUE: return NF_QUEUE; @@ -413,6 +418,10 @@ { int status; struct nf_info *info; +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + struct net_device *physindev = NULL; + struct net_device *physoutdev = NULL; +#endif if (!queue_handler[pf].outfn) { kfree_skb(skb); @@ -435,11 +444,24 @@ if (indev) dev_hold(indev); if (outdev) dev_hold(outdev); +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + if (skb->nf_bridge) { + physindev = skb->nf_bridge->physindev; + if (physindev) dev_hold(physindev); + physoutdev = skb->nf_bridge->physoutdev; + if (physoutdev) dev_hold(physoutdev); + } +#endif + status = queue_handler[pf].outfn(skb, info, queue_handler[pf].data); if (status < 0) { /* James M doesn't say fuck enough. */ if (indev) dev_put(indev); if (outdev) dev_put(outdev); +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + if (physindev) dev_put(physindev); + if (physoutdev) dev_put(physoutdev); +#endif kfree(info); kfree_skb(skb); return; @@ -449,7 +471,8 @@ int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, struct net_device *indev, struct net_device *outdev, - int (*okfn)(struct sk_buff *)) + int (*okfn)(struct sk_buff *), + int hook_thresh) { struct list_head *elem; unsigned int verdict; @@ -481,7 +504,7 @@ elem = &nf_hooks[pf][hook]; verdict = nf_iterate(&nf_hooks[pf][hook], &skb, hook, indev, - outdev, &elem, okfn); + outdev, &elem, okfn, hook_thresh); if (verdict == NF_QUEUE) { NFDEBUG("nf_hook: Verdict = QUEUE.\n"); nf_queue(skb, elem, pf, hook, indev, outdev, okfn); @@ -530,7 +553,7 @@ verdict = nf_iterate(&nf_hooks[info->pf][info->hook], &skb, info->hook, info->indev, info->outdev, &elem, - info->okfn); + info->okfn, INT_MIN); } switch (verdict) { --- linux-2.5.44/net/core/skbuff.c Sat Oct 19 06:01:17 2002 +++ linux-2.5.44-brnfpre3/net/core/skbuff.c Thu Oct 24 18:32:34 2002 @@ -248,6 +248,9 @@ #ifdef CONFIG_NETFILTER_DEBUG skb->nf_debug = 0; #endif +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + skb->nf_bridge = NULL; +#endif #endif #ifdef CONFIG_NET_SCHED skb->tc_index = 0; @@ -327,6 +330,9 @@ } #ifdef CONFIG_NETFILTER nf_conntrack_put(skb->nfct); +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + nf_bridge_put(skb->nf_bridge); +#endif #endif skb_headerinit(skb, NULL, 0); /* clean state */ kfree_skbmem(skb); @@ -392,6 +398,9 @@ #ifdef CONFIG_NETFILTER_DEBUG C(nf_debug); #endif +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + C(nf_bridge); +#endif #endif /*CONFIG_NETFILTER*/ #if defined(CONFIG_HIPPI) C(private); @@ -404,6 +413,9 @@ skb->cloned = 1; #ifdef CONFIG_NETFILTER nf_conntrack_get(skb->nfct); +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + nf_bridge_get(skb->nf_bridge); +#endif #endif return n; } @@ -437,6 +449,10 @@ nf_conntrack_get(new->nfct); #ifdef CONFIG_NETFILTER_DEBUG new->nf_debug = old->nf_debug; +#endif +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + new->nf_bridge = old->nf_bridge; + nf_bridge_get(new->nf_bridge); #endif #endif #ifdef CONFIG_NET_SCHED --- linux-2.5.44/net/ipv4/ip_output.c Sat Oct 19 06:02:34 2002 +++ linux-2.5.44-brnfpre3/net/ipv4/ip_output.c Thu Oct 24 18:32:34 2002 @@ -396,6 +396,10 @@ /* Connection association is same as pre-frag packet */ to->nfct = from->nfct; nf_conntrack_get(to->nfct); +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + to->nf_bridge = from->nf_bridge; + nf_bridge_get(to->nf_bridge); +#endif #ifdef CONFIG_NETFILTER_DEBUG to->nf_debug = from->nf_debug; #endif --- linux-2.5.44/net/ipv4/netfilter/ipt_LOG.c Sat Oct 19 06:01:21 2002 +++ linux-2.5.44-brnfpre3/net/ipv4/netfilter/ipt_LOG.c Thu Oct 24 18:58:08 2002 @@ -289,6 +289,18 @@ loginfo->prefix, in ? in->name : "", out ? out->name : ""); +#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) + if ((*pskb)->nf_bridge) { + struct net_device *physindev = (*pskb)->nf_bridge->physindev; + struct net_device *physoutdev = (*pskb)->nf_bridge->physoutdev; + + if (physindev && in != physindev) + printk("PHYSIN=%s ", physindev->name); + if (physoutdev && out != physoutdev) + printk("PHYSOUT=%s ", physoutdev->name); + } +#endif + if (in && !out) { /* MAC logging for input chain only. */ printk("MAC="); --- /dev/null Thu Aug 24 11:00:32 2000 +++ linux-2.5.44-brnfpre3/net/bridge/br_netfilter.c Thu Oct 24 18:32:34 2002 @@ -0,0 +1,614 @@ +/* + * Handle firewalling + * Linux ethernet bridge + * + * Authors: + * Lennert Buytenhek + * Bart De Schuymer + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "br_private.h" + + +#define skb_origaddr(skb) (((struct bridge_skb_cb *) \ + (skb->cb))->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 clear_cb(skb) (memset(&skb_origaddr(skb), 0, \ + sizeof(struct bridge_skb_cb))) + +#define has_bridge_parent(device) ((device)->br_port != NULL) +#define bridge_parent(device) (&((device)->br_port->br->dev)) + +/* 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, + pmtu: 1500 + } + }, + + rt_flags: 0 +}; + + +/* PF_BRIDGE/PRE_ROUTING *********************************************/ +static void __br_dnat_complain(void) +{ + static unsigned long last_complaint = 0; + + 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() will return success. The source + * address for ip_route_output() is set to zero, so ip_route_output() + * 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) +{ +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug |= (1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_FORWARD); +#endif + + if (skb->pkt_type == PACKET_OTHERHOST) { + skb->pkt_type = PACKET_HOST; + skb->nf_bridge->mask |= BRNF_PKT_TYPE; + } + + skb->dev = bridge_parent(skb->dev); + 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; + +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug ^= (1 << NF_BR_PRE_ROUTING); +#endif + + if (nf_bridge->mask & BRNF_PKT_TYPE) { + skb->pkt_type = PACKET_OTHERHOST; + nf_bridge->mask ^= BRNF_PKT_TYPE; + } + + if (dnat_took_place(skb)) { + if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, + dev)) { + struct rtable *rt; + + if (!ip_route_output(&rt, iph->daddr, 0, iph->tos, 0)) { + /* Bridged-and-DNAT'ed traffic doesn't + * require ip_forwarding. + */ + if (((struct dst_entry *)rt)->dev == dev) { + skb->dst = (struct dst_entry *)rt; + goto bridged_dnat; + } + __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; + clear_cb(skb); + NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, + skb, skb->dev, NULL, + br_nf_pre_routing_finish_bridge, + 1); + return 0; + } + memcpy(skb->mac.ethernet->h_dest, dev->dev_addr, + ETH_ALEN); + } + } else { + skb->dst = (struct dst_entry *)&__fake_rtable; + dst_hold(skb->dst); + } + + clear_cb(skb); + skb->dev = nf_bridge->physindev; + NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, + br_handle_frame_finish, 1); + + return 0; +} + +/* 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; + struct nf_bridge_info *nf_bridge; + + if ((*pskb)->protocol != __constant_htons(ETH_P_IP)) + return NF_ACCEPT; + + if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL) + goto out; + + 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; + } + +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug ^= (1 << NF_IP_PRE_ROUTING); +#endif + if ((nf_bridge = nf_bridge_alloc(skb)) == NULL) + return NF_DROP; + + if (skb->pkt_type == PACKET_OTHERHOST) { + skb->pkt_type = PACKET_HOST; + nf_bridge->mask |= BRNF_PKT_TYPE; + } + + nf_bridge->physindev = skb->dev; + skb->dev = bridge_parent(skb->dev); + 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->protocol != __constant_htons(ETH_P_IP)) + return NF_ACCEPT; + + 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; + +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug ^= (1 << NF_BR_FORWARD); +#endif + + if (nf_bridge->mask & BRNF_PKT_TYPE) { + skb->pkt_type = PACKET_OTHERHOST; + nf_bridge->mask ^= BRNF_PKT_TYPE; + } + + NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, nf_bridge->physindev, + skb->dev, br_forward_finish, 1); + + return 0; +} + +/* This is the 'purely bridged' case. 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 another bit of the bridge-nf patch overloads the + * '-i' and '-o' iptables interface checks to take + * skb->phys{in,out}dev into account as well (so both the real + * device and the bridge device will match). + */ +static unsigned int br_nf_forward(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; + + if (skb->protocol != __constant_htons(ETH_P_IP)) + return NF_ACCEPT; + +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug ^= (1 << NF_BR_FORWARD); +#endif + + nf_bridge = skb->nf_bridge; + if (skb->pkt_type == PACKET_OTHERHOST) { + skb->pkt_type = PACKET_HOST; + nf_bridge->mask |= BRNF_PKT_TYPE; + } + + nf_bridge->physoutdev = skb->dev; + + NF_HOOK(PF_INET, NF_IP_FORWARD, skb, bridge_parent(nf_bridge->physindev), + bridge_parent(skb->dev), br_nf_forward_finish); + + return NF_STOLEN; +} + + +/* PF_BRIDGE/LOCAL_OUT ***********************************************/ +static int br_nf_local_out_finish(struct sk_buff *skb) +{ +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug &= ~(1 << NF_BR_LOCAL_OUT); +#endif + + 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. + * For the sake of interface transparency (i.e. properly + * overloading the '-o' option), 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. ipv4_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 *)) +{ + int (*okfn)(struct sk_buff *skb); + struct net_device *realindev; + struct sk_buff *skb = *pskb; + struct nf_bridge_info *nf_bridge; + + if (skb->protocol != __constant_htons(ETH_P_IP)) + return NF_ACCEPT; + + /* Sometimes we get packets with NULL ->dst here (for example, + * running a dhcp client daemon triggers this). + */ + if (skb->dst == NULL) + return NF_ACCEPT; + + 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) { + okfn = br_forward_finish; + + if (nf_bridge->mask & BRNF_PKT_TYPE) { + skb->pkt_type = PACKET_OTHERHOST; + nf_bridge->mask ^= BRNF_PKT_TYPE; + } + + NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev, + skb->dev, okfn); + } else { + okfn = br_nf_local_out_finish; + /* IP forwarded traffic has a physindev, locally + * generated traffic hasn't. + */ + if (realindev != NULL) { + if (((nf_bridge->mask & BRNF_DONT_TAKE_PARENT) == 0) && + has_bridge_parent(realindev)) + realindev = bridge_parent(realindev); + + NF_HOOK_THRESH(PF_INET, NF_IP_FORWARD, skb, realindev, + bridge_parent(skb->dev), okfn, + NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1); + } else { +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug ^= (1 << NF_IP_LOCAL_OUT); +#endif + + NF_HOOK_THRESH(PF_INET, NF_IP_LOCAL_OUT, skb, realindev, + bridge_parent(skb->dev), okfn, + NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1); + } + } + + 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; + + /* Be very paranoid. */ + 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."); + if (skb->dev != NULL) { + printk("[%s]", skb->dev->name); + if (has_bridge_parent(skb->dev)) + printk("[%s]", bridge_parent(skb->dev)->name); + } + printk("\n"); + return NF_ACCEPT; + } + + if (skb->protocol != __constant_htons(ETH_P_IP)) + return NF_ACCEPT; + + /* Sometimes we get packets with NULL ->dst here (for example, + * running a dhcp client daemon triggers this). + */ + if (skb->dst == NULL) + return NF_ACCEPT; + +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug ^= (1 << NF_IP_POST_ROUTING); +#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; + } + + memcpy(nf_bridge->hh, skb->data - 16, 16); + + NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, + bridge_parent(skb->dev), br_dev_queue_push_xmit); + + return NF_STOLEN; +} + + +/* IPv4/SABOTAGE *****************************************************/ + +/* Don't hand locally destined packets to PF_INET/PRE_ROUTING + * for the second time. + */ +static unsigned int ipv4_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 (in->hard_start_xmit == br_dev_xmit && + okfn != br_nf_pre_routing_finish) { + okfn(*pskb); + return NF_STOLEN; + } + + return NF_ACCEPT; +} + +/* Postpone execution of PF_INET/FORWARD, PF_INET/LOCAL_OUT + * and PF_INET/POST_ROUTING until we have done the forwarding + * decision in the bridge code and have determined skb->physoutdev. + */ +static unsigned int ipv4_sabotage_out(unsigned int hook, struct sk_buff **pskb, + const struct net_device *in, const struct net_device *out, + int (*okfn)(struct sk_buff *)) +{ + 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) { + struct sk_buff *skb = *pskb; + struct nf_bridge_info *nf_bridge; + + if (!skb->nf_bridge && !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; + } + okfn(skb); + return NF_STOLEN; + } + + 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[] = { + { { NULL, NULL }, br_nf_pre_routing, PF_BRIDGE, NF_BR_PRE_ROUTING, NF_BR_PRI_BRNF }, + { { NULL, NULL }, br_nf_local_in, PF_BRIDGE, NF_BR_LOCAL_IN, NF_BR_PRI_BRNF }, + { { NULL, NULL }, br_nf_forward, PF_BRIDGE, NF_BR_FORWARD, NF_BR_PRI_BRNF }, + { { NULL, NULL }, br_nf_local_out, PF_BRIDGE, NF_BR_LOCAL_OUT, NF_BR_PRI_FIRST }, + { { NULL, NULL }, br_nf_post_routing, PF_BRIDGE, NF_BR_POST_ROUTING, NF_BR_PRI_LAST }, + { { NULL, NULL }, ipv4_sabotage_in, PF_INET, NF_IP_PRE_ROUTING, NF_IP_PRI_FIRST }, + { { NULL, NULL }, ipv4_sabotage_out, PF_INET, NF_IP_FORWARD, NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD }, + { { NULL, NULL }, ipv4_sabotage_out, PF_INET, NF_IP_LOCAL_OUT, NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT }, + { { NULL, NULL }, ipv4_sabotage_out, PF_INET, NF_IP_POST_ROUTING, NF_IP_PRI_FIRST } +}; + +#define NUMHOOKS (sizeof(br_nf_ops)/sizeof(br_nf_ops[0])) + +int br_netfilter_init(void) +{ + int i; + + for (i = 0; i < NUMHOOKS; 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; + } + + printk(KERN_NOTICE "Bridge firewalling registered\n"); + + return 0; +} + +void br_netfilter_fini(void) +{ + int i; + + for (i = NUMHOOKS - 1; i >= 0; i--) + nf_unregister_hook(&br_nf_ops[i]); +} - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/