@@ -2,7 +2,19 @@
#define __LINUX_ERSPAN_H
/*
- * GRE header for ERSPAN encapsulation (8 octets [34:41]) -- 8 bytes
+ * GRE header for ERSPAN type I encapsulation (4 octets [34:37])
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |0|0|0|0|0|00000|000000000|00000| Protocol Type for ERSPAN |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * The Type I ERSPAN frame format is based on the barebones IP + GRE
+ * encapsulation (as described above) on top of the raw mirrored frame.
+ * There is no extra ERSPAN header.
+ *
+ *
+ * GRE header for ERSPAN type II and II encapsulation (8 octets [34:41])
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -43,7 +55,7 @@
* | Platform Specific Info |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
- * GRE proto ERSPAN type II = 0x88BE, type III = 0x22EB
+ * GRE proto ERSPAN type I/II = 0x88BE, type III = 0x22EB
*/
#include <uapi/linux/erspan.h>
@@ -139,6 +151,9 @@ static inline u8 get_hwid(const struct erspan_md2 *md2)
static inline int erspan_hdr_len(int version)
{
+ if (version == 0)
+ return 0;
+
return sizeof(struct erspan_base_hdr) +
(version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
}
@@ -248,6 +248,15 @@ static void gre_err(struct sk_buff *skb, u32 info)
ipgre_err(skb, info, &tpi);
}
+static inline bool is_erspan_type1(int gre_hdr_len)
+{
+ /* Both ERSPAN type I (version 0) and type II (version 1) use
+ * protocol 0x88BE, but the type I has only 4-byte GRE header,
+ * while type II has 8-byte.
+ */
+ return gre_hdr_len == 4;
+}
+
static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
int gre_hdr_len)
{
@@ -262,17 +271,26 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
int len;
itn = net_generic(net, erspan_net_id);
-
iph = ip_hdr(skb);
- ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
- ver = ershdr->ver;
-
- tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
- tpi->flags | TUNNEL_KEY,
- iph->saddr, iph->daddr, tpi->key);
+ if (is_erspan_type1(gre_hdr_len)) {
+ ver = 0;
+ tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
+ tpi->flags | TUNNEL_NO_KEY,
+ iph->saddr, iph->daddr, 0);
+ } else {
+ ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
+ ver = ershdr->ver;
+ tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
+ tpi->flags | TUNNEL_KEY,
+ iph->saddr, iph->daddr, tpi->key);
+ }
if (tunnel) {
- len = gre_hdr_len + erspan_hdr_len(ver);
+ if (is_erspan_type1(gre_hdr_len))
+ len = gre_hdr_len;
+ else
+ len = gre_hdr_len + erspan_hdr_len(ver);
+
if (unlikely(!pskb_may_pull(skb, len)))
return PACKET_REJECT;
@@ -665,7 +683,10 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
}
/* Push ERSPAN header */
- if (tunnel->erspan_ver == 1) {
+ if (tunnel->erspan_ver == 0) {
+ proto = htons(ETH_P_ERSPAN);
+ tunnel->parms.o_flags &= ~TUNNEL_SEQ;
+ } else if (tunnel->erspan_ver == 1) {
erspan_build_header(skb, ntohl(tunnel->parms.o_key),
tunnel->index,
truncate, true);
@@ -1066,7 +1087,10 @@ static int erspan_validate(struct nlattr *tb[], struct nlattr *data[],
if (ret)
return ret;
- /* ERSPAN should only have GRE sequence and key flag */
+ if (nla_get_u8(data[IFLA_GRE_ERSPAN_VER]) == 0)
+ return 0;
+
+ /* ERSPAN type II/III should only have GRE sequence and key flag */
if (data[IFLA_GRE_OFLAGS])
flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
if (data[IFLA_GRE_IFLAGS])
@@ -1174,7 +1198,7 @@ static int erspan_netlink_parms(struct net_device *dev,
if (data[IFLA_GRE_ERSPAN_VER]) {
t->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]);
- if (t->erspan_ver != 1 && t->erspan_ver != 2)
+ if (t->erspan_ver > 2)
return -EINVAL;
}
@@ -1259,7 +1283,11 @@ static int erspan_tunnel_init(struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
- tunnel->tun_hlen = 8;
+ if (tunnel->erspan_ver == 0)
+ tunnel->tun_hlen = 4; /* 4-byte GRE hdr. */
+ else
+ tunnel->tun_hlen = 8; /* 8-byte GRE hdr. */
+
tunnel->parms.iph.protocol = IPPROTO_GRE;
tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
erspan_hdr_len(tunnel->erspan_ver);
@@ -1456,8 +1484,8 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
struct ip_tunnel_parm *p = &t->parms;
__be16 o_flags = p->o_flags;
- if (t->erspan_ver == 1 || t->erspan_ver == 2) {
- if (!t->collect_md)
+ if (t->erspan_ver <= 2) {
+ if (t->erspan_ver != 0 && !t->collect_md)
o_flags |= TUNNEL_KEY;
if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
@@ -1466,7 +1494,7 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
if (t->erspan_ver == 1) {
if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index))
goto nla_put_failure;
- } else {
+ } else if (t->erspan_ver == 2) {
if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir))
goto nla_put_failure;
if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid))
The Type I ERSPAN frame format is based on the barebones IP + GRE(4-byte) encapsulation on top of the raw mirrored frame. Both type I and II use 0x88BE as protocol type. Unlike type II and III, no sequence number or key is required. To creat a type I erspan tunnel device: $ ip link add dev erspan11 type erspan \ local 172.16.1.100 remote 172.16.1.200 \ erspan_ver 0 CC: Dmitriy Andreyevskiy <dandreye@cisco.com> Signed-off-by: William Tu <u9012063@gmail.com> --- I didn't notice there is Type I when I did first erspan type II/III code because it is not in the ietf draft 00 and 01. It's until recently I got request for adding type I. Spec is below at draft 02: https://tools.ietf.org/html/draft-foschiano-erspan-02#section-4.1 To verify with Wireshark, make sure you have: commit ef76d65fc61d01c2ce5184140f4b1bba0019078b Author: Guy Harris <guy@alum.mit.edu> Date: Mon Sep 30 16:35:35 2019 -0700 Fix checks for "do we have an ERSPAN header?" --- include/net/erspan.h | 19 +++++++++++++++-- net/ipv4/ip_gre.c | 58 ++++++++++++++++++++++++++++++++++++++-------------- 2 files changed, 60 insertions(+), 17 deletions(-)