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Revision v1 of 2 in this series.

Revisions (2)
  1. v1 current
  2. v2 [diff vs current]

[PATCH net-next 10/23] netfilter: flowtable: add vlan support

From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2021-03-11 00:37:19
Also in: netfilter-devel
Subsystem: netfilter, networking [general], the rest · Maintainers: Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

Add the vlan id and protocol to the flow tuple to uniquely identify
flows from the receive path. For the transmit path, dev_hard_header() on
the vlan device push the headers. This patch includes support for two
vlan headers (QinQ) from the ingress path.

Add a generic encap field to the flowtable entry which stores the
protocol and the tag id. This allows to reuse these fields in the PPPoE
support coming in a later patch.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_flow_table.h |  17 +++-
 net/netfilter/nf_flow_table_core.c    |   7 ++
 net/netfilter/nf_flow_table_ip.c      | 123 +++++++++++++++++++++-----
 net/netfilter/nft_flow_offload.c      |  26 +++++-
 4 files changed, 147 insertions(+), 26 deletions(-)
diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h
index 83110e4705c0..8742b3351150 100644
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -95,6 +95,8 @@ enum flow_offload_xmit_type {
 	FLOW_OFFLOAD_XMIT_DIRECT,
 };
 
+#define NF_FLOW_TABLE_ENCAP_MAX		2
+
 struct flow_offload_tuple {
 	union {
 		struct in_addr		src_v4;
@@ -113,13 +115,17 @@ struct flow_offload_tuple {
 
 	u8				l3proto;
 	u8				l4proto;
+	struct {
+		u16			id;
+		__be16			proto;
+	} encap[NF_FLOW_TABLE_ENCAP_MAX];
 
 	/* All members above are keys for lookups, see flow_offload_hash(). */
 	struct { }			__hash;
 
-	u8				dir:6,
-					xmit_type:2;
-
+	u8				dir:4,
+					xmit_type:2,
+					encap_num:2;
 	u16				mtu;
 	union {
 		struct dst_entry	*dst_cache;
@@ -174,6 +180,11 @@ struct nf_flow_route {
 		struct dst_entry		*dst;
 		struct {
 			u32			ifindex;
+			struct {
+				u16		id;
+				__be16		proto;
+			} encap[NF_FLOW_TABLE_ENCAP_MAX];
+			u8			num_encaps;
 		} in;
 		struct {
 			u32			ifindex;
diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index a4cfbefbb6da..d4aec1c988d0 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -80,6 +80,7 @@ static int flow_offload_fill_route(struct flow_offload *flow,
 {
 	struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
 	struct dst_entry *dst = route->tuple[dir].dst;
+	int i, j = 0;
 
 	switch (flow_tuple->l3proto) {
 	case NFPROTO_IPV4:
@@ -91,6 +92,12 @@ static int flow_offload_fill_route(struct flow_offload *flow,
 	}
 
 	flow_tuple->iifidx = route->tuple[dir].in.ifindex;
+	for (i = route->tuple[dir].in.num_encaps - 1; i >= 0; i--) {
+		flow_tuple->encap[j].id = route->tuple[dir].in.encap[i].id;
+		flow_tuple->encap[j].proto = route->tuple[dir].in.encap[i].proto;
+		j++;
+	}
+	flow_tuple->encap_num = route->tuple[dir].in.num_encaps;
 
 	switch (route->tuple[dir].xmit_type) {
 	case FLOW_OFFLOAD_XMIT_DIRECT:
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index ae0b008c639a..127e9b9ffe10 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -159,17 +159,38 @@ static bool ip_has_options(unsigned int thoff)
 	return thoff != sizeof(struct iphdr);
 }
 
+static void nf_flow_tuple_encap(struct sk_buff *skb,
+				struct flow_offload_tuple *tuple)
+{
+	int i = 0;
+
+	if (skb_vlan_tag_present(skb)) {
+		tuple->encap[i].id = skb_vlan_tag_get(skb);
+		tuple->encap[i].proto = skb->vlan_proto;
+		i++;
+	}
+	if (skb->protocol == htons(ETH_P_8021Q)) {
+		struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb_mac_header(skb);
+
+		tuple->encap[i].id = ntohs(veth->h_vlan_TCI);
+		tuple->encap[i].proto = skb->protocol;
+	}
+}
+
 static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
 			    struct flow_offload_tuple *tuple)
 {
-	unsigned int thoff, hdrsize;
+	unsigned int thoff, hdrsize, offset = 0;
 	struct flow_ports *ports;
 	struct iphdr *iph;
 
-	if (!pskb_may_pull(skb, sizeof(*iph)))
+	if (skb->protocol == htons(ETH_P_8021Q))
+		offset += VLAN_HLEN;
+
+	if (!pskb_may_pull(skb, sizeof(*iph) + offset))
 		return -1;
 
-	iph = ip_hdr(skb);
+	iph = (struct iphdr *)(skb_network_header(skb) + offset);
 	thoff = iph->ihl * 4;
 
 	if (ip_is_fragment(iph) ||
@@ -191,11 +212,11 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
 		return -1;
 
 	thoff = iph->ihl * 4;
-	if (!pskb_may_pull(skb, thoff + hdrsize))
+	if (!pskb_may_pull(skb, thoff + hdrsize + offset))
 		return -1;
 
-	iph = ip_hdr(skb);
-	ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
+	iph = (struct iphdr *)(skb_network_header(skb) + offset);
+	ports = (struct flow_ports *)(skb_network_header(skb) + thoff + offset);
 
 	tuple->src_v4.s_addr	= iph->saddr;
 	tuple->dst_v4.s_addr	= iph->daddr;
@@ -204,6 +225,7 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
 	tuple->l3proto		= AF_INET;
 	tuple->l4proto		= iph->protocol;
 	tuple->iifidx		= dev->ifindex;
+	nf_flow_tuple_encap(skb, tuple);
 
 	return 0;
 }
@@ -248,6 +270,40 @@ static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
 	return NF_STOLEN;
 }
 
+static bool nf_flow_skb_encap_protocol(const struct sk_buff *skb, __be16 proto)
+{
+	if (skb->protocol == htons(ETH_P_8021Q)) {
+		struct vlan_ethhdr *veth;
+
+		veth = (struct vlan_ethhdr *)skb_mac_header(skb);
+		if (veth->h_vlan_encapsulated_proto == proto)
+			return true;
+	}
+
+	return false;
+}
+
+static void nf_flow_encap_pop(struct sk_buff *skb,
+			      struct flow_offload_tuple_rhash *tuplehash)
+{
+	struct vlan_hdr *vlan_hdr;
+	int i;
+
+	for (i = 0; i < tuplehash->tuple.encap_num; i++) {
+		if (skb_vlan_tag_present(skb)) {
+			__vlan_hwaccel_clear_tag(skb);
+			continue;
+		}
+		if (skb->protocol == htons(ETH_P_8021Q)) {
+			vlan_hdr = (struct vlan_hdr *)skb->data;
+			__skb_pull(skb, VLAN_HLEN);
+			vlan_set_encap_proto(skb, vlan_hdr);
+			skb_reset_network_header(skb);
+			break;
+		}
+	}
+}
+
 static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb,
 				       const struct flow_offload_tuple_rhash *tuplehash,
 				       unsigned short type)
@@ -276,13 +332,15 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 	enum flow_offload_tuple_dir dir;
 	struct flow_offload *flow;
 	struct net_device *outdev;
+	unsigned int thoff, mtu;
 	struct rtable *rt;
-	unsigned int thoff;
 	struct iphdr *iph;
 	__be32 nexthop;
+	u32 offset = 0;
 	int ret;
 
-	if (skb->protocol != htons(ETH_P_IP))
+	if (skb->protocol != htons(ETH_P_IP) &&
+	    !nf_flow_skb_encap_protocol(skb, htons(ETH_P_IP)))
 		return NF_ACCEPT;
 
 	if (nf_flow_tuple_ip(skb, state->in, &tuple) < 0)
@@ -295,14 +353,19 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 
-	if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
+	mtu = flow->tuplehash[dir].tuple.mtu + offset;
+	if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
 		return NF_ACCEPT;
 
-	if (skb_try_make_writable(skb, sizeof(*iph)))
+	if (skb->protocol == htons(ETH_P_8021Q))
+		offset += VLAN_HLEN;
+
+	if (skb_try_make_writable(skb, sizeof(*iph) + offset))
 		return NF_DROP;
 
-	thoff = ip_hdr(skb)->ihl * 4;
-	if (nf_flow_state_check(flow, ip_hdr(skb)->protocol, skb, thoff))
+	iph = (struct iphdr *)(skb_network_header(skb) + offset);
+	thoff = (iph->ihl * 4) + offset;
+	if (nf_flow_state_check(flow, iph->protocol, skb, thoff))
 		return NF_ACCEPT;
 
 	flow_offload_refresh(flow_table, flow);
@@ -312,6 +375,9 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 		return NF_ACCEPT;
 	}
 
+	nf_flow_encap_pop(skb, tuplehash);
+	thoff -= offset;
+
 	if (nf_flow_nat_ip(flow, skb, thoff, dir) < 0)
 		return NF_DROP;
 
@@ -479,14 +545,17 @@ static int nf_flow_nat_ipv6(const struct flow_offload *flow,
 static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
 			      struct flow_offload_tuple *tuple)
 {
-	unsigned int thoff, hdrsize;
+	unsigned int thoff, hdrsize, offset = 0;
 	struct flow_ports *ports;
 	struct ipv6hdr *ip6h;
 
-	if (!pskb_may_pull(skb, sizeof(*ip6h)))
+	if (skb->protocol == htons(ETH_P_8021Q))
+		offset += VLAN_HLEN;
+
+	if (!pskb_may_pull(skb, sizeof(*ip6h) + offset))
 		return -1;
 
-	ip6h = ipv6_hdr(skb);
+	ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
 
 	switch (ip6h->nexthdr) {
 	case IPPROTO_TCP:
@@ -503,11 +572,11 @@ static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
 		return -1;
 
 	thoff = sizeof(*ip6h);
-	if (!pskb_may_pull(skb, thoff + hdrsize))
+	if (!pskb_may_pull(skb, thoff + hdrsize + offset))
 		return -1;
 
-	ip6h = ipv6_hdr(skb);
-	ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
+	ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
+	ports = (struct flow_ports *)(skb_network_header(skb) + thoff + offset);
 
 	tuple->src_v6		= ip6h->saddr;
 	tuple->dst_v6		= ip6h->daddr;
@@ -516,6 +585,7 @@ static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
 	tuple->l3proto		= AF_INET6;
 	tuple->l4proto		= ip6h->nexthdr;
 	tuple->iifidx		= dev->ifindex;
+	nf_flow_tuple_encap(skb, tuple);
 
 	return 0;
 }
@@ -533,9 +603,12 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 	struct net_device *outdev;
 	struct ipv6hdr *ip6h;
 	struct rt6_info *rt;
+	unsigned int mtu;
+	u32 offset = 0;
 	int ret;
 
-	if (skb->protocol != htons(ETH_P_IPV6))
+	if (skb->protocol != htons(ETH_P_IPV6) &&
+	    !nf_flow_skb_encap_protocol(skb, htons(ETH_P_IPV6)))
 		return NF_ACCEPT;
 
 	if (nf_flow_tuple_ipv6(skb, state->in, &tuple) < 0)
@@ -548,11 +621,15 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 
-	if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
+	mtu = flow->tuplehash[dir].tuple.mtu + offset;
+	if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
 		return NF_ACCEPT;
 
-	if (nf_flow_state_check(flow, ipv6_hdr(skb)->nexthdr, skb,
-				sizeof(*ip6h)))
+	if (skb->protocol == htons(ETH_P_8021Q))
+		offset += VLAN_HLEN;
+
+	ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
+	if (nf_flow_state_check(flow, ip6h->nexthdr, skb, sizeof(*ip6h)))
 		return NF_ACCEPT;
 
 	flow_offload_refresh(flow_table, flow);
@@ -562,6 +639,8 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 		return NF_ACCEPT;
 	}
 
+	nf_flow_encap_pop(skb, tuplehash);
+
 	if (skb_try_make_writable(skb, sizeof(*ip6h)))
 		return NF_DROP;
 
diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index a6595dca1b1f..8392b1a8108b 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -66,6 +66,11 @@ static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
 struct nft_forward_info {
 	const struct net_device *indev;
 	const struct net_device *outdev;
+	struct id {
+		__u16	id;
+		__be16	proto;
+	} encap[NF_FLOW_TABLE_ENCAP_MAX];
+	u8 num_encaps;
 	u8 h_source[ETH_ALEN];
 	u8 h_dest[ETH_ALEN];
 	enum flow_offload_xmit_type xmit_type;
@@ -84,9 +89,23 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 		path = &stack->path[i];
 		switch (path->type) {
 		case DEV_PATH_ETHERNET:
+		case DEV_PATH_VLAN:
 			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;
+
+			/* DEV_PATH_VLAN */
+			if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {
+				info->indev = NULL;
+				break;
+			}
+			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++;
 			break;
 		case DEV_PATH_BRIDGE:
 			if (is_zero_ether_addr(info->h_source))
@@ -94,7 +113,6 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 
 			info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
 			break;
-		case DEV_PATH_VLAN:
 		default:
 			info->indev = NULL;
 			break;
@@ -130,6 +148,7 @@ static void nft_dev_forward_path(struct nf_flow_route *route,
 	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);
@@ -138,6 +157,11 @@ static void nft_dev_forward_path(struct nf_flow_route *route,
 		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;
 
 	if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) {
 		memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN);
-- 
2.20.1
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