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gre: receive also TEB packets for lwtunnels

PATCH In review Jiri Benc 3 participants 6 messages May 3, 2016 – May 4, 2016

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Networking Network drivers IPv4/IPv6
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Jiri Benc

author
#0 lore raw

cover gre: receive also TEB packets for lwtunnels

NOTE: this patchset needs net merged to net-next.

This allows lwtunnel users to get also packets with ETH_P_TEB protocol specified in GRE header through an ipgre interface. There's really nothing special about these packets in the case of lwtunnels - it's just an inner protocol like any other. The only complications stem from keeping compatibility with other uses of GRE.

This will be used by openvswitch to support eth_push and eth_pop actions. I'd also like to see tc support for lwtunnels (this feature included) in the future.

The first patch is not directly related and can be submitted standalone if needed.

Jiri Benc (3):
gre: remove superfluous pskb_may_pull
gre: move iptunnel_pull_header down to ipgre_rcv
gre: receive also TEB packets for lwtunnels

 include/net/ip_tunnels.h |  1 +
 net/ipv4/gre_demux.c     |  5 +----
 net/ipv4/ip_gre.c        | 48 +++++++++++++++++++++++++++++++++++-------------
 3 files changed, 37 insertions(+), 17 deletions(-)
Signature · 1 line
1.8.3.1
author
#1 lore raw

PATCH 1/3 gre: remove superfluous pskb_may_pull

The call to gre_parse_header is either followed by iptunnel_pull_header, or in the case of ICMP error path, the actual header is not accessed at all.

In the first case, iptunnel_pull_header will call pskb_may_pull anyway and it's pointless to do it twice. The only difference is what call will fail with what error code but the net effect is still the same in all call sites.

In the second case, pskb_may_pull is pointless, as skb->data is at the outer IP header and not at the GRE header.

Signed-off-by Jiri Benc <[email protected]>
---
 net/ipv4/gre_demux.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
net/ipv4/gre_demux.c +1 -4
index a41e73ab1369..d78e2eefc0f7 100644
@@ -114,11 +114,8 @@ int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 	 */
 	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
 		tpi->proto = htons(ETH_P_IP);
-		if ((*(u8 *)options & 0xF0) != 0x40) {
+		if ((*(u8 *)options & 0xF0) != 0x40)
 			hdr_len += 4;
-			if (!pskb_may_pull(skb, hdr_len))
-				return -EINVAL;
-		}
 	}
 	return hdr_len;
 }
Signature · 1 line
1.8.3.1
author
#2 lore raw

PATCH 2/3 gre: move iptunnel_pull_header down to ipgre_rcv

In reply to Jiri Benc

This will allow to make the pull dependent on the tunnel type.

Signed-off-by Jiri Benc <[email protected]>
---
 net/ipv4/ip_gre.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)
net/ipv4/ip_gre.c +10 -5
index 8260a707b9b8..8f377dad5489 100644
@@ -260,7 +260,8 @@ static __be32 tunnel_id_to_key(__be64 x)
 #endif
 }
 
-static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
+static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
+		     int hdr_len)
 {
 	struct net *net = dev_net(skb->dev);
 	struct metadata_dst *tun_dst = NULL;

@@ -278,6 +279,9 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
 				  iph->saddr, iph->daddr, tpi->key);
 
 	if (tunnel) {
+		if (iptunnel_pull_header(skb, hdr_len, tpi->proto, false) < 0)
+			goto drop;
+
 		skb_pop_mac_header(skb);
 		if (tunnel->collect_md) {
 			__be16 flags;

@@ -294,6 +298,10 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
 		return PACKET_RCVD;
 	}
 	return PACKET_REJECT;
+
+drop:
+	kfree_skb(skb);
+	return PACKET_RCVD;
 }
 
 static int gre_rcv(struct sk_buff *skb)

@@ -314,10 +322,7 @@ static int gre_rcv(struct sk_buff *skb)
 	if (hdr_len < 0)
 		goto drop;
 
-	if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false))
-		goto drop;
-
-	if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)
+	if (ipgre_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
 		return 0;
 
 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
Signature · 1 line
1.8.3.1
author
#3 lore raw

PATCH 3/3 gre: receive also TEB packets for lwtunnels

In reply to Jiri Benc

For ipgre interfaces in collect metadata mode, receive also traffic with encapsulated Ethernet headers. The lwtunnel users are supposed to sort this out correctly. This allows to have mixed Ethernet + L3-only traffic on the same lwtunnel interface. This is the same way as VXLAN-GPE behaves.

To keep backwards compatibility and prevent any surprises, gretap interfaces have priority in receiving packets with Ethernet headers.

Signed-off-by Jiri Benc <[email protected]>
---
 include/net/ip_tunnels.h |  1 +
 net/ipv4/ip_gre.c        | 39 ++++++++++++++++++++++++++++-----------
 2 files changed, 29 insertions(+), 11 deletions(-)
include/net/ip_tunnels.h +1 -0
index 6d790910ebdf..d916b4315903 100644
@@ -160,6 +160,7 @@ struct tnl_ptk_info {
 
 #define PACKET_RCVD	0
 #define PACKET_REJECT	1
+#define PACKET_NEXT	2
 
 #define IP_TNL_HASH_BITS   7
 #define IP_TNL_HASH_SIZE   (1 << IP_TNL_HASH_BITS)
net/ipv4/ip_gre.c +28 -11
index 8f377dad5489..2b267e71ebf5 100644
@@ -260,26 +260,20 @@ static __be32 tunnel_id_to_key(__be64 x)
 #endif
 }
 
-static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
-		     int hdr_len)
+static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
+		       struct ip_tunnel_net *itn, int hdr_len, bool raw_proto)
 {
-	struct net *net = dev_net(skb->dev);
 	struct metadata_dst *tun_dst = NULL;
-	struct ip_tunnel_net *itn;
 	const struct iphdr *iph;
 	struct ip_tunnel *tunnel;
 
-	if (tpi->proto == htons(ETH_P_TEB))
-		itn = net_generic(net, gre_tap_net_id);
-	else
-		itn = net_generic(net, ipgre_net_id);
-
 	iph = ip_hdr(skb);
 	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
 				  iph->saddr, iph->daddr, tpi->key);
 
 	if (tunnel) {
-		if (iptunnel_pull_header(skb, hdr_len, tpi->proto, false) < 0)
+		if (__iptunnel_pull_header(skb, hdr_len, tpi->proto,
+					   raw_proto, false) < 0)
 			goto drop;
 
 		skb_pop_mac_header(skb);

@@ -297,13 +291,36 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 		ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
 		return PACKET_RCVD;
 	}
-	return PACKET_REJECT;
+	return PACKET_NEXT;
 
 drop:
 	kfree_skb(skb);
 	return PACKET_RCVD;
 }
 
+static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
+		     int hdr_len)
+{
+	struct net *net = dev_net(skb->dev);
+	struct ip_tunnel_net *itn;
+	int res;
+
+	if (tpi->proto == htons(ETH_P_TEB))
+		itn = net_generic(net, gre_tap_net_id);
+	else
+		itn = net_generic(net, ipgre_net_id);
+
+	res = __ipgre_rcv(skb, tpi, itn, hdr_len, false);
+	if (res == PACKET_NEXT && tpi->proto == htons(ETH_P_TEB)) {
+		/* ipgre tunnels in collect metadata mode should receive
+		 * also ETH_P_TEB traffic.
+		 */
+		itn = net_generic(net, ipgre_net_id);
+		res = __ipgre_rcv(skb, tpi, itn, hdr_len, true);
+	}
+	return res;
+}
+
 static int gre_rcv(struct sk_buff *skb)
 {
 	struct tnl_ptk_info tpi;
Signature · 1 line
1.8.3.1
Tested-by on the v1 series
#4 lore raw
In reply to Jiri Benc
Quoted 8 lines · Jiri Benc

NOTE: this patchset needs net merged to net-next.

This allows lwtunnel users to get also packets with ETH_P_TEB protocol specified in GRE header through an ipgre interface. There's really nothing special about these packets in the case of lwtunnels - it's just an inner protocol like any other. The only complications stem from keeping compatibility with other uses of GRE.

Quoted 6 lines

This will be used by openvswitch to support eth_push and eth_pop actions. I'd also like to see tc support for lwtunnels (this feature included) in the future.

The first patch is not directly related and can be submitted standalone if needed.

I have exercised this patch-set using Open vSwitch both with and without the patchset I posted earlier this afternoon to make use of this new feature:

"[PATCH v9 net-next 0/7] openvswitch: support for layer 3 encapsulated packets"

All three patches:

Tested-by Simon Horman <[email protected]>
Quoted 13 lines

Jiri Benc (3):
gre: remove superfluous pskb_may_pull
gre: move iptunnel_pull_header down to ipgre_rcv
gre: receive also TEB packets for lwtunnels

 include/net/ip_tunnels.h |  1 +
 net/ipv4/gre_demux.c     |  5 +----
 net/ipv4/ip_gre.c        | 48 +++++++++++++++++++++++++++++++++++-------------
 3 files changed, 37 insertions(+), 17 deletions(-)
Signature · 1 line
1.8.3.1
maintainer
#5 lore raw
In reply to Jiri Benc

From: Jiri Benc <[email protected]>
Date: Tue, 3 May 2016 17:10:05 +0200

Quoted 1 line

NOTE: this patchset needs net merged to net-next.

Noted.

Quoted 6 lines

This allows lwtunnel users to get also packets with ETH_P_TEB protocol specified in GRE header through an ipgre interface. There's really nothing special about these packets in the case of lwtunnels - it's just an inner protocol like any other. The only complications stem from keeping compatibility with other uses of GRE.

Quoted 6 lines

This will be used by openvswitch to support eth_push and eth_pop actions. I'd also like to see tc support for lwtunnels (this feature included) in the future.

The first patch is not directly related and can be submitted standalone if needed.

Series applied, thanks Jiri.