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Message-Id: <1503678089-27131-3-git-send-email-u9012063@gmail.com>
Date: Fri, 25 Aug 2017 09:21:28 -0700
From: William Tu <u9012063@...il.com>
To: netdev@...r.kernel.org
Subject: [PATCH net-next 2/3] 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@...il.com>
---
include/net/ip_tunnels.h | 4 +-
net/ipv4/ip_gre.c | 102 +++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 101 insertions(+), 5 deletions(-)
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 625c29329372..992652856fe8 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -154,8 +154,10 @@ struct ip_tunnel {
#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)
-#define TUNNEL_OPTIONS_PRESENT (TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT)
+#define TUNNEL_OPTIONS_PRESENT \
+ (TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT | TUNNEL_ERSPAN_OPT)
struct tnl_ptk_info {
__be16 flags;
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 453b7925b940..0162fb955b33 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -113,6 +113,8 @@ MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
static struct rtnl_link_ops ipgre_link_ops __read_mostly;
static int ipgre_tunnel_init(struct net_device *dev);
+static void erspan_build_header(struct sk_buff *skb,
+ __be32 id, u32 index, bool truncate);
static unsigned int ipgre_net_id __read_mostly;
static unsigned int gre_tap_net_id __read_mostly;
@@ -287,7 +289,33 @@ 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);
+
+ tun_dst = ip_tun_rx_dst(skb, flags,
+ tun_id, sizeof(*md));
+ if (!tun_dst)
+ return PACKET_REJECT;
+
+ 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);
ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
return PACKET_RCVD;
@@ -523,6 +551,64 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
dev->stats.tx_dropped++;
}
+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;
+ 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);
+
+ gre_build_header(skb, 8, TUNNEL_SEQ,
+ htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++));
+
+ 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++;
+}
+
static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
{
struct ip_tunnel_info *info = skb_tunnel_info(skb);
@@ -636,6 +722,11 @@ 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;
@@ -998,9 +1089,12 @@ 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
--
2.7.4
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