[ovs-dev,ERSPAN,RFC,04/25] compat/gre: add collect_md mode

Message ID 1521756461-3870-5-git-send-email-gvrose8192@gmail.com
State RFC
Headers show
Series
  • Introduce ERSPAN for OVS
Related show

Commit Message

Greg Rose March 22, 2018, 10:07 p.m.
From: William Tu <u9012063@gmail.com>

    commit 1a66a836da630cd70f3639208da549b549ce576b
    Author: William Tu <u9012063@gmail.com>
    Date:   Fri Aug 25 09:21:28 2017 -0700

    gre: add collect_md mode to ERSPAN tunnel

    Similar to gre, vxlan, geneve, ipip tunnels, allow ERSPAN tunnels to
    operate in 'collect metadata' mode.  bpf_skb_[gs]et_tunnel_key() helpers
    can make use of it right away.  OVS can use it as well in the future.

    Signed-off-by: William Tu <u9012063@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

With some adjustments for compatibility layer.

Cc: William Tu <u9012063@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
---
 datapath/linux/compat/include/net/ip_tunnels.h |  68 ++++++++------
 datapath/linux/compat/ip_gre.c                 | 117 ++++++++++++++++++++++---
 2 files changed, 146 insertions(+), 39 deletions(-)

Patch

diff --git a/datapath/linux/compat/include/net/ip_tunnels.h b/datapath/linux/compat/include/net/ip_tunnels.h
index e3fb13b..159eb48 100644
--- a/datapath/linux/compat/include/net/ip_tunnels.h
+++ b/datapath/linux/compat/include/net/ip_tunnels.h
@@ -74,14 +74,25 @@  void rpl_ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 
 
 #ifndef TUNNEL_CSUM
-#define TUNNEL_CSUM	__cpu_to_be16(0x01)
-#define TUNNEL_ROUTING	__cpu_to_be16(0x02)
-#define TUNNEL_KEY	__cpu_to_be16(0x04)
-#define TUNNEL_SEQ	__cpu_to_be16(0x08)
-#define TUNNEL_STRICT	__cpu_to_be16(0x10)
-#define TUNNEL_REC	__cpu_to_be16(0x20)
-#define TUNNEL_VERSION	__cpu_to_be16(0x40)
-#define TUNNEL_NO_KEY	__cpu_to_be16(0x80)
+#define TUNNEL_CSUM		__cpu_to_be16(0x01)
+#define TUNNEL_ROUTING		__cpu_to_be16(0x02)
+#define TUNNEL_KEY		__cpu_to_be16(0x04)
+#define TUNNEL_SEQ		__cpu_to_be16(0x08)
+#define TUNNEL_STRICT		__cpu_to_be16(0x10)
+#define TUNNEL_REC		__cpu_to_be16(0x20)
+#define TUNNEL_VERSION		__cpu_to_be16(0x40)
+#define TUNNEL_NO_KEY		__cpu_to_be16(0x80)
+#define TUNNEL_DONT_FRAGMENT    __cpu_to_be16(0x0100)
+#define TUNNEL_OAM		__cpu_to_be16(0x0200)
+#define TUNNEL_CRIT_OPT		__cpu_to_be16(0x0400)
+#define TUNNEL_GENEVE_OPT	__cpu_to_be16(0x0800)
+#define TUNNEL_VXLAN_OPT	__cpu_to_be16(0x1000)
+#define TUNNEL_NOCACHE		__cpu_to_be16(0x2000)
+#define TUNNEL_ERSPAN_OPT	__cpu_to_be16(0x4000)
+
+#undef TUNNEL_OPTIONS_PRESENT
+#define TUNNEL_OPTIONS_PRESENT \
+		(TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT | TUNNEL_ERSPAN_OPT)
 
 struct tnl_ptk_info {
 	__be16 flags;
@@ -100,27 +111,6 @@  struct tnl_ptk_info {
 #define IP_TNL_HASH_BITS   7
 #define IP_TNL_HASH_SIZE   (1 << IP_TNL_HASH_BITS)
 
-#ifndef TUNNEL_DONT_FRAGMENT
-#define TUNNEL_DONT_FRAGMENT	__cpu_to_be16(0x0100)
-#endif
-
-#ifndef TUNNEL_OAM
-#define TUNNEL_OAM	__cpu_to_be16(0x0200)
-#define TUNNEL_CRIT_OPT	__cpu_to_be16(0x0400)
-#endif
-
-#ifndef TUNNEL_GENEVE_OPT
-#define TUNNEL_GENEVE_OPT	__cpu_to_be16(0x0800)
-#endif
-
-#ifndef TUNNEL_VXLAN_OPT
-#define TUNNEL_VXLAN_OPT	__cpu_to_be16(0x1000)
-#endif
-
-/* Older kernels defined TUNNEL_OPTIONS_PRESENT to GENEVE only */
-#undef TUNNEL_OPTIONS_PRESENT
-#define TUNNEL_OPTIONS_PRESENT (TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT)
-
 /* Keep error state on tunnel for 30 sec */
 #define IPTUNNEL_ERR_TIMEO	(30*HZ)
 
@@ -243,6 +233,7 @@  static inline void ip_tunnel_key_init(struct ip_tunnel_key *key,
 #define ip_tunnel_collect_metadata() true
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4,6,0)
+#undef TUNNEL_NOCACHE
 #define TUNNEL_NOCACHE 0
 
 static inline bool
@@ -420,6 +411,25 @@  static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len)
 	}
 }
 
+static inline __be64 key32_to_tunnel_id(__be32 key)
+{
+#ifdef __BIG_ENDIAN
+	return (__force __be64)key;
+#else
+	return (__force __be64)((__force u64)key << 32);
+#endif
+}
+
+/* Returns the least-significant 32 bits of a __be64. */
+static inline __be32 tunnel_id_to_key32(__be64 tun_id)
+{
+#ifdef __BIG_ENDIAN
+	return (__force __be32)tun_id;
+#else
+	return (__force __be32)((__force u64)tun_id >> 32);
+#endif
+}
+
 #define ip_tunnel_init rpl_ip_tunnel_init
 int rpl_ip_tunnel_init(struct net_device *dev);
 
diff --git a/datapath/linux/compat/ip_gre.c b/datapath/linux/compat/ip_gre.c
index d25d2df..d0f112d 100644
--- a/datapath/linux/compat/ip_gre.c
+++ b/datapath/linux/compat/ip_gre.c
@@ -122,6 +122,9 @@  static __be32 tunnel_id_to_key(__be64 x)
 #endif
 }
 
+static void erspan_build_header(struct sk_buff *skb,
+				__be32 id, u32 index, bool truncate);
+
 /* Called with rcu_read_lock and BH disabled. */
 static int gre_err(struct sk_buff *skb, u32 info,
 		   const struct tnl_ptk_info *tpi)
@@ -133,7 +136,7 @@  static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 		      int gre_hdr_len)
 {
 	struct net *net = dev_net(skb->dev);
-	struct metadata_dst *tun_dst = NULL;
+	struct metadata_dst tun_dst;
 	struct ip_tunnel_net *itn;
 	struct ip_tunnel *tunnel;
 	struct erspanhdr *ershdr;
@@ -169,9 +172,33 @@  static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 					   false, false) < 0)
 			goto drop;
 
-		tunnel->index = ntohl(index);
+		if (tunnel->collect_md) {
+			struct ip_tunnel_info *info;
+			struct erspan_metadata *md;
+			__be64 tun_id;
+			__be16 flags;
+
+			tpi->flags |= TUNNEL_KEY;
+			flags = tpi->flags;
+			tun_id = key32_to_tunnel_id(tpi->key);
+
+			ovs_ip_tun_rx_dst(&tun_dst, skb, flags,
+					  tun_id, sizeof(*md));
+
+			md = ip_tunnel_info_opts(&tun_dst.u.tun_info);
+			if (!md)
+				return PACKET_REJECT;
+
+			md->index = index;
+			info = &tun_dst.u.tun_info;
+			info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
+			info->options_len = sizeof(*md);
+		} else {
+			tunnel->index = ntohl(index);
+		}
+
 		skb_reset_mac_header(skb);
-		ovs_ip_tunnel_rcv(tunnel->dev, skb, tun_dst);
+		ovs_ip_tunnel_rcv(tunnel->dev, skb, &tun_dst);
 		return PACKET_RCVD;
 	}
 drop:
@@ -484,6 +511,72 @@  err_free_skb:
 }
 EXPORT_SYMBOL(rpl_gre_fb_xmit);
 
+
+
+static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
+			   __be16 proto)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct ip_tunnel_info *tun_info;
+	const struct ip_tunnel_key *key;
+	struct erspan_metadata *md;
+	struct rtable *rt = NULL;
+	struct tnl_ptk_info tpi;
+	bool truncate = false;
+	struct flowi4 fl;
+	int tunnel_hlen;
+	__be16 df;
+
+	tun_info = skb_tunnel_info(skb);
+	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
+		     ip_tunnel_info_af(tun_info) != AF_INET))
+		goto err_free_skb;
+
+	key = &tun_info->key;
+
+	/* ERSPAN has fixed 8 byte GRE header */
+	tunnel_hlen = 8 + sizeof(struct erspanhdr);
+
+	rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
+	if (!rt)
+		return;
+
+	if (gre_handle_offloads(skb, false))
+		goto err_free_rt;
+
+	if (skb->len > dev->mtu) {
+		pskb_trim(skb, dev->mtu);
+		truncate = true;
+	}
+
+	md = ip_tunnel_info_opts(tun_info);
+	if (!md)
+		goto err_free_rt;
+
+	erspan_build_header(skb, tunnel_id_to_key32(key->tun_id),
+			    ntohl(md->index), truncate);
+
+	tpi.flags = (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ);
+	tpi.proto = htons(ETH_P_ERSPAN);
+	tpi.key = tunnel_id_to_key32(key->tun_id);
+	tpi.seq = htonl(tunnel->o_seqno++);
+	tpi.hdr_len = 8;
+
+	gre_build_header(skb, &tpi, 8);
+
+	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;
+
+	iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,
+		      key->tos, key->ttl, df, false);
+	return;
+
+err_free_rt:
+	ip_rt_put(rt);
+err_free_skb:
+	kfree_skb(skb);
+	dev->stats.tx_dropped++;
+}
+
 #define GRE_FEATURES	(NETIF_F_SG |		\
 			 NETIF_F_FRAGLIST |	\
 			 NETIF_F_HIGHDMA |	\
@@ -608,18 +701,17 @@  static int erspan_validate(struct nlattr *tb[], struct nlattr *data[])
 		return ret;
 
 	/* ERSPAN should only have GRE sequence and key flag */
-	flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
-	flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
-	if (flags != (GRE_SEQ | GRE_KEY))
+	if (data[IFLA_GRE_OFLAGS])
+		flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
+	if (data[IFLA_GRE_IFLAGS])
+		flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
+	if (!data[IFLA_GRE_COLLECT_METADATA] &&
+	    flags != (GRE_SEQ | GRE_KEY))
 		return -EINVAL;
 
 	/* ERSPAN Session ID only has 10-bit. Since we reuse
 	 * 32-bit key field as ID, check it's range.
 	 */
-	if (data[IFLA_GRE_IKEY] &&
-	    (ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK))
-		return -EINVAL;
-
 	if (data[IFLA_GRE_OKEY] &&
 	    (ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK))
 		return -EINVAL;
@@ -708,6 +800,11 @@  static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 	struct ip_tunnel *tunnel = netdev_priv(dev);
 	bool truncate = false;
 
+	if (tunnel->collect_md) {
+		erspan_fb_xmit(skb, dev, skb->protocol);
+		return NETDEV_TX_OK;
+	}
+
 	if (gre_handle_offloads(skb, false))
 		goto free_skb;