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Message-ID: <20251126205611.1284486-2-pablo@netfilter.org>
Date: Wed, 26 Nov 2025 20:55:56 +0000
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net,
netdev@...r.kernel.org,
kuba@...nel.org,
pabeni@...hat.com,
edumazet@...gle.com,
fw@...len.de,
horms@...nel.org
Subject: [PATCH net-next 01/16] netfilter: flowtable: move path discovery infrastructure to its own file
This file contains the path discovery that is run from the forward chain
for the packet offloading the flow into the flowtable. This consists
of a series of calls to dev_fill_forward_path() for each device stack.
More topologies may be supported in the future, so move this code to its
own file to separate it from the nftables flow_offload expression.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/nf_flow_table.h | 6 +
net/netfilter/Makefile | 1 +
net/netfilter/nf_flow_table_path.c | 267 ++++++++++++++++++++++++++
net/netfilter/nft_flow_offload.c | 252 ------------------------
4 files changed, 274 insertions(+), 252 deletions(-)
create mode 100644 net/netfilter/nf_flow_table_path.c
diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h
index c003cd194fa2..e9f72d2558e9 100644
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -222,6 +222,12 @@ struct nf_flow_route {
struct flow_offload *flow_offload_alloc(struct nf_conn *ct);
void flow_offload_free(struct flow_offload *flow);
+struct nft_flowtable;
+struct nft_pktinfo;
+int nft_flow_route(const struct nft_pktinfo *pkt, const struct nf_conn *ct,
+ struct nf_flow_route *route, enum ip_conntrack_dir dir,
+ struct nft_flowtable *ft);
+
static inline int
nf_flow_table_offload_add_cb(struct nf_flowtable *flow_table,
flow_setup_cb_t *cb, void *cb_priv)
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index e43e20f529f8..6bfc250e474f 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -141,6 +141,7 @@ obj-$(CONFIG_NFT_FWD_NETDEV) += nft_fwd_netdev.o
# flow table infrastructure
obj-$(CONFIG_NF_FLOW_TABLE) += nf_flow_table.o
nf_flow_table-objs := nf_flow_table_core.o nf_flow_table_ip.o \
+ nf_flow_table_path.o \
nf_flow_table_offload.o nf_flow_table_xdp.o
nf_flow_table-$(CONFIG_NF_FLOW_TABLE_PROCFS) += nf_flow_table_procfs.o
ifeq ($(CONFIG_NF_FLOW_TABLE),m)
diff --git a/net/netfilter/nf_flow_table_path.c b/net/netfilter/nf_flow_table_path.c
new file mode 100644
index 000000000000..159aa5c8da60
--- /dev/null
+++ b/net/netfilter/nf_flow_table_path.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/spinlock.h>
+#include <linux/netfilter/nf_conntrack_common.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/ip.h>
+#include <net/inet_dscp.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_flow_table.h>
+
+static enum flow_offload_xmit_type nft_xmit_type(struct dst_entry *dst)
+{
+ if (dst_xfrm(dst))
+ return FLOW_OFFLOAD_XMIT_XFRM;
+
+ return FLOW_OFFLOAD_XMIT_NEIGH;
+}
+
+static void nft_default_forward_path(struct nf_flow_route *route,
+ struct dst_entry *dst_cache,
+ enum ip_conntrack_dir dir)
+{
+ route->tuple[!dir].in.ifindex = dst_cache->dev->ifindex;
+ route->tuple[dir].dst = dst_cache;
+ route->tuple[dir].xmit_type = nft_xmit_type(dst_cache);
+}
+
+static bool nft_is_valid_ether_device(const struct net_device *dev)
+{
+ if (!dev || (dev->flags & IFF_LOOPBACK) || dev->type != ARPHRD_ETHER ||
+ dev->addr_len != ETH_ALEN || !is_valid_ether_addr(dev->dev_addr))
+ return false;
+
+ return true;
+}
+
+static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
+ const struct dst_entry *dst_cache,
+ const struct nf_conn *ct,
+ enum ip_conntrack_dir dir, u8 *ha,
+ struct net_device_path_stack *stack)
+{
+ const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
+ struct net_device *dev = dst_cache->dev;
+ struct neighbour *n;
+ u8 nud_state;
+
+ if (!nft_is_valid_ether_device(dev))
+ goto out;
+
+ n = dst_neigh_lookup(dst_cache, daddr);
+ if (!n)
+ return -1;
+
+ read_lock_bh(&n->lock);
+ nud_state = n->nud_state;
+ ether_addr_copy(ha, n->ha);
+ read_unlock_bh(&n->lock);
+ neigh_release(n);
+
+ if (!(nud_state & NUD_VALID))
+ return -1;
+
+out:
+ return dev_fill_forward_path(dev, ha, stack);
+}
+
+struct nft_forward_info {
+ const struct net_device *indev;
+ const struct net_device *outdev;
+ const struct net_device *hw_outdev;
+ struct id {
+ __u16 id;
+ __be16 proto;
+ } encap[NF_FLOW_TABLE_ENCAP_MAX];
+ u8 num_encaps;
+ u8 ingress_vlans;
+ u8 h_source[ETH_ALEN];
+ u8 h_dest[ETH_ALEN];
+ enum flow_offload_xmit_type xmit_type;
+};
+
+static void nft_dev_path_info(const struct net_device_path_stack *stack,
+ struct nft_forward_info *info,
+ unsigned char *ha, struct nf_flowtable *flowtable)
+{
+ const struct net_device_path *path;
+ int i;
+
+ memcpy(info->h_dest, ha, ETH_ALEN);
+
+ for (i = 0; i < stack->num_paths; i++) {
+ path = &stack->path[i];
+ switch (path->type) {
+ case DEV_PATH_ETHERNET:
+ case DEV_PATH_DSA:
+ case DEV_PATH_VLAN:
+ case DEV_PATH_PPPOE:
+ info->indev = path->dev;
+ if (is_zero_ether_addr(info->h_source))
+ memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
+
+ if (path->type == DEV_PATH_ETHERNET)
+ break;
+ if (path->type == DEV_PATH_DSA) {
+ i = stack->num_paths;
+ break;
+ }
+
+ /* DEV_PATH_VLAN and DEV_PATH_PPPOE */
+ if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {
+ info->indev = NULL;
+ break;
+ }
+ if (!info->outdev)
+ info->outdev = path->dev;
+ info->encap[info->num_encaps].id = path->encap.id;
+ info->encap[info->num_encaps].proto = path->encap.proto;
+ info->num_encaps++;
+ if (path->type == DEV_PATH_PPPOE)
+ memcpy(info->h_dest, path->encap.h_dest, ETH_ALEN);
+ break;
+ case DEV_PATH_BRIDGE:
+ if (is_zero_ether_addr(info->h_source))
+ memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
+
+ switch (path->bridge.vlan_mode) {
+ case DEV_PATH_BR_VLAN_UNTAG_HW:
+ info->ingress_vlans |= BIT(info->num_encaps - 1);
+ break;
+ case DEV_PATH_BR_VLAN_TAG:
+ info->encap[info->num_encaps].id = path->bridge.vlan_id;
+ info->encap[info->num_encaps].proto = path->bridge.vlan_proto;
+ info->num_encaps++;
+ break;
+ case DEV_PATH_BR_VLAN_UNTAG:
+ info->num_encaps--;
+ break;
+ case DEV_PATH_BR_VLAN_KEEP:
+ break;
+ }
+ info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
+ break;
+ default:
+ info->indev = NULL;
+ break;
+ }
+ }
+ if (!info->outdev)
+ info->outdev = info->indev;
+
+ info->hw_outdev = info->indev;
+
+ if (nf_flowtable_hw_offload(flowtable) &&
+ nft_is_valid_ether_device(info->indev))
+ info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
+}
+
+static bool nft_flowtable_find_dev(const struct net_device *dev,
+ struct nft_flowtable *ft)
+{
+ struct nft_hook *hook;
+ bool found = false;
+
+ list_for_each_entry_rcu(hook, &ft->hook_list, list) {
+ if (!nft_hook_find_ops_rcu(hook, dev))
+ continue;
+
+ found = true;
+ break;
+ }
+
+ return found;
+}
+
+static void nft_dev_forward_path(struct nf_flow_route *route,
+ const struct nf_conn *ct,
+ enum ip_conntrack_dir dir,
+ struct nft_flowtable *ft)
+{
+ const struct dst_entry *dst = route->tuple[dir].dst;
+ struct net_device_path_stack stack;
+ struct nft_forward_info info = {};
+ unsigned char ha[ETH_ALEN];
+ int i;
+
+ if (nft_dev_fill_forward_path(route, dst, ct, dir, ha, &stack) >= 0)
+ nft_dev_path_info(&stack, &info, ha, &ft->data);
+
+ if (!info.indev || !nft_flowtable_find_dev(info.indev, ft))
+ return;
+
+ route->tuple[!dir].in.ifindex = info.indev->ifindex;
+ for (i = 0; i < info.num_encaps; i++) {
+ route->tuple[!dir].in.encap[i].id = info.encap[i].id;
+ route->tuple[!dir].in.encap[i].proto = info.encap[i].proto;
+ }
+ route->tuple[!dir].in.num_encaps = info.num_encaps;
+ route->tuple[!dir].in.ingress_vlans = info.ingress_vlans;
+
+ if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) {
+ memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN);
+ memcpy(route->tuple[dir].out.h_dest, info.h_dest, ETH_ALEN);
+ route->tuple[dir].out.ifindex = info.outdev->ifindex;
+ route->tuple[dir].out.hw_ifindex = info.hw_outdev->ifindex;
+ route->tuple[dir].xmit_type = info.xmit_type;
+ }
+}
+
+int nft_flow_route(const struct nft_pktinfo *pkt, const struct nf_conn *ct,
+ struct nf_flow_route *route, enum ip_conntrack_dir dir,
+ struct nft_flowtable *ft)
+{
+ struct dst_entry *this_dst = skb_dst(pkt->skb);
+ struct dst_entry *other_dst = NULL;
+ struct flowi fl;
+
+ memset(&fl, 0, sizeof(fl));
+ switch (nft_pf(pkt)) {
+ case NFPROTO_IPV4:
+ fl.u.ip4.daddr = ct->tuplehash[dir].tuple.src.u3.ip;
+ fl.u.ip4.saddr = ct->tuplehash[!dir].tuple.src.u3.ip;
+ fl.u.ip4.flowi4_oif = nft_in(pkt)->ifindex;
+ fl.u.ip4.flowi4_iif = this_dst->dev->ifindex;
+ fl.u.ip4.flowi4_dscp = ip4h_dscp(ip_hdr(pkt->skb));
+ fl.u.ip4.flowi4_mark = pkt->skb->mark;
+ fl.u.ip4.flowi4_flags = FLOWI_FLAG_ANYSRC;
+ break;
+ case NFPROTO_IPV6:
+ fl.u.ip6.daddr = ct->tuplehash[dir].tuple.src.u3.in6;
+ fl.u.ip6.saddr = ct->tuplehash[!dir].tuple.src.u3.in6;
+ fl.u.ip6.flowi6_oif = nft_in(pkt)->ifindex;
+ fl.u.ip6.flowi6_iif = this_dst->dev->ifindex;
+ fl.u.ip6.flowlabel = ip6_flowinfo(ipv6_hdr(pkt->skb));
+ fl.u.ip6.flowi6_mark = pkt->skb->mark;
+ fl.u.ip6.flowi6_flags = FLOWI_FLAG_ANYSRC;
+ break;
+ }
+
+ if (!dst_hold_safe(this_dst))
+ return -ENOENT;
+
+ nf_route(nft_net(pkt), &other_dst, &fl, false, nft_pf(pkt));
+ if (!other_dst) {
+ dst_release(this_dst);
+ return -ENOENT;
+ }
+
+ nft_default_forward_path(route, this_dst, dir);
+ nft_default_forward_path(route, other_dst, !dir);
+
+ if (route->tuple[dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH &&
+ route->tuple[!dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH) {
+ nft_dev_forward_path(route, ct, dir, ft);
+ nft_dev_forward_path(route, ct, !dir, ft);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nft_flow_route);
diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 14dd1c0698c3..b8f76c9057fd 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -20,258 +20,6 @@ struct nft_flow_offload {
struct nft_flowtable *flowtable;
};
-static enum flow_offload_xmit_type nft_xmit_type(struct dst_entry *dst)
-{
- if (dst_xfrm(dst))
- return FLOW_OFFLOAD_XMIT_XFRM;
-
- return FLOW_OFFLOAD_XMIT_NEIGH;
-}
-
-static void nft_default_forward_path(struct nf_flow_route *route,
- struct dst_entry *dst_cache,
- enum ip_conntrack_dir dir)
-{
- route->tuple[!dir].in.ifindex = dst_cache->dev->ifindex;
- route->tuple[dir].dst = dst_cache;
- route->tuple[dir].xmit_type = nft_xmit_type(dst_cache);
-}
-
-static bool nft_is_valid_ether_device(const struct net_device *dev)
-{
- if (!dev || (dev->flags & IFF_LOOPBACK) || dev->type != ARPHRD_ETHER ||
- dev->addr_len != ETH_ALEN || !is_valid_ether_addr(dev->dev_addr))
- return false;
-
- return true;
-}
-
-static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
- const struct dst_entry *dst_cache,
- const struct nf_conn *ct,
- enum ip_conntrack_dir dir, u8 *ha,
- struct net_device_path_stack *stack)
-{
- const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
- struct net_device *dev = dst_cache->dev;
- struct neighbour *n;
- u8 nud_state;
-
- if (!nft_is_valid_ether_device(dev))
- goto out;
-
- n = dst_neigh_lookup(dst_cache, daddr);
- if (!n)
- return -1;
-
- read_lock_bh(&n->lock);
- nud_state = n->nud_state;
- ether_addr_copy(ha, n->ha);
- read_unlock_bh(&n->lock);
- neigh_release(n);
-
- if (!(nud_state & NUD_VALID))
- return -1;
-
-out:
- return dev_fill_forward_path(dev, ha, stack);
-}
-
-struct nft_forward_info {
- const struct net_device *indev;
- const struct net_device *outdev;
- const struct net_device *hw_outdev;
- struct id {
- __u16 id;
- __be16 proto;
- } encap[NF_FLOW_TABLE_ENCAP_MAX];
- u8 num_encaps;
- u8 ingress_vlans;
- u8 h_source[ETH_ALEN];
- u8 h_dest[ETH_ALEN];
- enum flow_offload_xmit_type xmit_type;
-};
-
-static void nft_dev_path_info(const struct net_device_path_stack *stack,
- struct nft_forward_info *info,
- unsigned char *ha, struct nf_flowtable *flowtable)
-{
- const struct net_device_path *path;
- int i;
-
- memcpy(info->h_dest, ha, ETH_ALEN);
-
- for (i = 0; i < stack->num_paths; i++) {
- path = &stack->path[i];
- switch (path->type) {
- case DEV_PATH_ETHERNET:
- case DEV_PATH_DSA:
- case DEV_PATH_VLAN:
- case DEV_PATH_PPPOE:
- info->indev = path->dev;
- if (is_zero_ether_addr(info->h_source))
- memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
-
- if (path->type == DEV_PATH_ETHERNET)
- break;
- if (path->type == DEV_PATH_DSA) {
- i = stack->num_paths;
- break;
- }
-
- /* DEV_PATH_VLAN and DEV_PATH_PPPOE */
- if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {
- info->indev = NULL;
- break;
- }
- if (!info->outdev)
- info->outdev = path->dev;
- info->encap[info->num_encaps].id = path->encap.id;
- info->encap[info->num_encaps].proto = path->encap.proto;
- info->num_encaps++;
- if (path->type == DEV_PATH_PPPOE)
- memcpy(info->h_dest, path->encap.h_dest, ETH_ALEN);
- break;
- case DEV_PATH_BRIDGE:
- if (is_zero_ether_addr(info->h_source))
- memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
-
- switch (path->bridge.vlan_mode) {
- case DEV_PATH_BR_VLAN_UNTAG_HW:
- info->ingress_vlans |= BIT(info->num_encaps - 1);
- break;
- case DEV_PATH_BR_VLAN_TAG:
- info->encap[info->num_encaps].id = path->bridge.vlan_id;
- info->encap[info->num_encaps].proto = path->bridge.vlan_proto;
- info->num_encaps++;
- break;
- case DEV_PATH_BR_VLAN_UNTAG:
- info->num_encaps--;
- break;
- case DEV_PATH_BR_VLAN_KEEP:
- break;
- }
- info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
- break;
- default:
- info->indev = NULL;
- break;
- }
- }
- if (!info->outdev)
- info->outdev = info->indev;
-
- info->hw_outdev = info->indev;
-
- if (nf_flowtable_hw_offload(flowtable) &&
- nft_is_valid_ether_device(info->indev))
- info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
-}
-
-static bool nft_flowtable_find_dev(const struct net_device *dev,
- struct nft_flowtable *ft)
-{
- struct nft_hook *hook;
- bool found = false;
-
- list_for_each_entry_rcu(hook, &ft->hook_list, list) {
- if (!nft_hook_find_ops_rcu(hook, dev))
- continue;
-
- found = true;
- break;
- }
-
- return found;
-}
-
-static void nft_dev_forward_path(struct nf_flow_route *route,
- const struct nf_conn *ct,
- enum ip_conntrack_dir dir,
- struct nft_flowtable *ft)
-{
- const struct dst_entry *dst = route->tuple[dir].dst;
- struct net_device_path_stack stack;
- struct nft_forward_info info = {};
- unsigned char ha[ETH_ALEN];
- int i;
-
- if (nft_dev_fill_forward_path(route, dst, ct, dir, ha, &stack) >= 0)
- nft_dev_path_info(&stack, &info, ha, &ft->data);
-
- if (!info.indev || !nft_flowtable_find_dev(info.indev, ft))
- return;
-
- route->tuple[!dir].in.ifindex = info.indev->ifindex;
- for (i = 0; i < info.num_encaps; i++) {
- route->tuple[!dir].in.encap[i].id = info.encap[i].id;
- route->tuple[!dir].in.encap[i].proto = info.encap[i].proto;
- }
- route->tuple[!dir].in.num_encaps = info.num_encaps;
- route->tuple[!dir].in.ingress_vlans = info.ingress_vlans;
-
- if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) {
- memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN);
- memcpy(route->tuple[dir].out.h_dest, info.h_dest, ETH_ALEN);
- route->tuple[dir].out.ifindex = info.outdev->ifindex;
- route->tuple[dir].out.hw_ifindex = info.hw_outdev->ifindex;
- route->tuple[dir].xmit_type = info.xmit_type;
- }
-}
-
-static int nft_flow_route(const struct nft_pktinfo *pkt,
- const struct nf_conn *ct,
- struct nf_flow_route *route,
- enum ip_conntrack_dir dir,
- struct nft_flowtable *ft)
-{
- struct dst_entry *this_dst = skb_dst(pkt->skb);
- struct dst_entry *other_dst = NULL;
- struct flowi fl;
-
- memset(&fl, 0, sizeof(fl));
- switch (nft_pf(pkt)) {
- case NFPROTO_IPV4:
- fl.u.ip4.daddr = ct->tuplehash[dir].tuple.src.u3.ip;
- fl.u.ip4.saddr = ct->tuplehash[!dir].tuple.src.u3.ip;
- fl.u.ip4.flowi4_oif = nft_in(pkt)->ifindex;
- fl.u.ip4.flowi4_iif = this_dst->dev->ifindex;
- fl.u.ip4.flowi4_dscp = ip4h_dscp(ip_hdr(pkt->skb));
- fl.u.ip4.flowi4_mark = pkt->skb->mark;
- fl.u.ip4.flowi4_flags = FLOWI_FLAG_ANYSRC;
- break;
- case NFPROTO_IPV6:
- fl.u.ip6.daddr = ct->tuplehash[dir].tuple.src.u3.in6;
- fl.u.ip6.saddr = ct->tuplehash[!dir].tuple.src.u3.in6;
- fl.u.ip6.flowi6_oif = nft_in(pkt)->ifindex;
- fl.u.ip6.flowi6_iif = this_dst->dev->ifindex;
- fl.u.ip6.flowlabel = ip6_flowinfo(ipv6_hdr(pkt->skb));
- fl.u.ip6.flowi6_mark = pkt->skb->mark;
- fl.u.ip6.flowi6_flags = FLOWI_FLAG_ANYSRC;
- break;
- }
-
- if (!dst_hold_safe(this_dst))
- return -ENOENT;
-
- nf_route(nft_net(pkt), &other_dst, &fl, false, nft_pf(pkt));
- if (!other_dst) {
- dst_release(this_dst);
- return -ENOENT;
- }
-
- nft_default_forward_path(route, this_dst, dir);
- nft_default_forward_path(route, other_dst, !dir);
-
- if (route->tuple[dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH &&
- route->tuple[!dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH) {
- nft_dev_forward_path(route, ct, dir, ft);
- nft_dev_forward_path(route, ct, !dir, ft);
- }
-
- return 0;
-}
-
static bool nft_flow_offload_skip(struct sk_buff *skb, int family)
{
if (skb_sec_path(skb))
--
2.47.3
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