[PATCH net] erspan: build the header with the right proto according to erspan_ver

From: Xin Long
Date: Mon Jan 14 2019 - 05:10:17 EST


As said in draft-foschiano-erspan-03#section4:

Different frame variants known as "ERSPAN Types" can be
distinguished based on the GRE "Protocol Type" field value: Type I
and II's value is 0x88BE while Type III's is 0x22EB [ETYPES].

So set it properly in erspan_xmit() according to erspan_ver. While at
it, also remove the unused parameter 'proto' in erspan_fb_xmit().

Fixes: 94d7d8f29287 ("ip6_gre: add erspan v2 support")
Reported-by: Jianlin Shi <jishi@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
---
net/ipv4/ip_gre.c | 23 ++++++++++++++---------
net/ipv6/ip6_gre.c | 6 ++++--
2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index d1d09f3..b1a74d8 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -569,8 +569,7 @@ 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)
+static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
struct ip_tunnel_info *tun_info;
@@ -578,10 +577,10 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
struct erspan_metadata *md;
struct rtable *rt = NULL;
bool truncate = false;
+ __be16 df, proto;
struct flowi4 fl;
int tunnel_hlen;
int version;
- __be16 df;
int nhoff;
int thoff;

@@ -626,18 +625,20 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
if (version == 1) {
erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)),
ntohl(md->u.index), truncate, true);
+ proto = htons(ETH_P_ERSPAN);
} else if (version == 2) {
erspan_build_header_v2(skb,
ntohl(tunnel_id_to_key32(key->tun_id)),
md->u.md2.dir,
get_hwid(&md->u.md2),
truncate, true);
+ proto = htons(ETH_P_ERSPAN2);
} else {
goto err_free_rt;
}

gre_build_header(skb, 8, TUNNEL_SEQ,
- htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++));
+ proto, 0, htonl(tunnel->o_seqno++));

df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;

@@ -721,12 +722,13 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
{
struct ip_tunnel *tunnel = netdev_priv(dev);
bool truncate = false;
+ __be16 proto;

if (!pskb_inet_may_pull(skb))
goto free_skb;

if (tunnel->collect_md) {
- erspan_fb_xmit(skb, dev, skb->protocol);
+ erspan_fb_xmit(skb, dev);
return NETDEV_TX_OK;
}

@@ -742,19 +744,22 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
}

/* Push ERSPAN header */
- if (tunnel->erspan_ver == 1)
+ if (tunnel->erspan_ver == 1) {
erspan_build_header(skb, ntohl(tunnel->parms.o_key),
tunnel->index,
truncate, true);
- else if (tunnel->erspan_ver == 2)
+ proto = htons(ETH_P_ERSPAN);
+ } else if (tunnel->erspan_ver == 2) {
erspan_build_header_v2(skb, ntohl(tunnel->parms.o_key),
tunnel->dir, tunnel->hwid,
truncate, true);
- else
+ proto = htons(ETH_P_ERSPAN2);
+ } else {
goto free_skb;
+ }

tunnel->parms.o_flags &= ~TUNNEL_KEY;
- __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_ERSPAN));
+ __gre_xmit(skb, dev, &tunnel->parms.iph, proto);
return NETDEV_TX_OK;

free_skb:
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 09d0826..12772d4 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -922,6 +922,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
__u8 dsfield = false;
struct flowi6 fl6;
int err = -EINVAL;
+ __be16 proto;
__u32 mtu;
int nhoff;
int thoff;
@@ -1035,8 +1036,9 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
}

/* Push GRE header. */
- gre_build_header(skb, 8, TUNNEL_SEQ,
- htons(ETH_P_ERSPAN), 0, htonl(t->o_seqno++));
+ proto = (t->parms.erspan_ver == 1) ? htons(ETH_P_ERSPAN)
+ : htons(ETH_P_ERSPAN2);
+ gre_build_header(skb, 8, TUNNEL_SEQ, proto, 0, htonl(t->o_seqno++));

/* TooBig packet may have updated dst->dev's mtu */
if (!t->parms.collect_md && dst && dst_mtu(dst) > dst->dev->mtu)
--
2.1.0