kernel: add eoip support

Thx do Developer_MZRIP

trunk/linux-3.4.x/include/net/gre.h

@@ -20,6 +20,14 @@ struct gre_full_hdr {
 #define GREPROTO_PPTP		1
 #define GREPROTO_MAX		2
 
+/* handle protocols with non-standard GRE header by ids that do not overlap
+ * with possible standard GRE protocol versions (0x00 - 0x7f)
+ */
+#define GREPROTO_NONSTD_BASE		0x80
+#define GREPROTO_NONSTD_EOIP		(0 + GREPROTO_NONSTD_BASE)
+#define GREPROTO_NONSTD_MAX		(1 + GREPROTO_NONSTD_BASE)
+
+
 struct gre_protocol {
 	int  (*handler)(struct sk_buff *skb);
 	void (*err_handler)(struct sk_buff *skb, u32 info);

trunk/linux-3.4.x/net/ipv4/Kconfig

@@ -184,7 +184,7 @@ config NET_IPGRE_DEMUX
 	tristate "IP: GRE demultiplexer"
 	help
 	 This is helper module to demultiplex GRE packets on GRE version field criteria.
-	 Required by ip_gre and pptp modules.
+	 Required by ip_gre, pptp and eoip modules.
 
 config NET_IPGRE
 	tristate "IP: GRE tunnels over IP"
@@ -209,6 +209,17 @@ config NET_IPGRE_BROADCAST
 	  Network), but can be distributed all over the Internet. If you want
 	  to do that, say Y here and to "IP multicast routing" below.
 
+config NET_EOIP
+	tristate "IP: EOIP ethernet tunnels over IP"
+	depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
+	help
+	  Tunneling means encapsulating data of one protocol type within
+	  another protocol and sending it over a channel that understands the
+	  encapsulating protocol. This particular tunneling driver implements
+	  MikroTik RouterOS compatible encapsulation of ethernet frames over
+	  existing IPv4 infrastructure. It is useful if the other endpoint
+	  is a MirkoTik router.
+
 config IP_MROUTE
 	bool "IP: multicast routing"
 	depends on IP_MULTICAST

trunk/linux-3.4.x/net/ipv4/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_IP_MROUTE) += ipmr.o
 obj-$(CONFIG_NET_IPIP) += ipip.o
 obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
 obj-$(CONFIG_NET_IPGRE) += ip_gre.o
+obj-$(CONFIG_NET_EOIP) += eoip.o
 obj-$(CONFIG_SYN_COOKIES) += syncookies.o
 obj-$(CONFIG_INET_AH) += ah4.o
 obj-$(CONFIG_INET_ESP) += esp4.o

trunk/linux-3.4.x/net/ipv4/eoip_version.h

@@ -0,0 +1,5 @@
+#ifndef __EOIP_VERSION_H__
+#define __EOIP_VERSION_H__
+#define EOIP_VERSION "1.0-3"
+#endif /* __EOIP_VERSION_H__ */
+

trunk/linux-3.4.x/net/ipv4/gre.c

@@ -23,14 +23,19 @@
 #include <net/protocol.h>
 #include <net/gre.h>
 
+#define GREPROTO_CNT \
+		(GREPROTO_MAX + GREPROTO_NONSTD_MAX - GREPROTO_NONSTD_BASE)
 
-static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
+static const struct gre_protocol __rcu *gre_proto[GREPROTO_CNT] __read_mostly;
 static DEFINE_SPINLOCK(gre_proto_lock);
 
 int gre_add_protocol(const struct gre_protocol *proto, u8 version)
 {
-	if (version >= GREPROTO_MAX)
-		goto err_out;
+	if (version >= GREPROTO_NONSTD_BASE && version < GREPROTO_NONSTD_MAX)
+		version -= GREPROTO_NONSTD_BASE - GREPROTO_MAX;
+	else
+		if (version >= GREPROTO_MAX)
+			goto err_out;
 
 	spin_lock(&gre_proto_lock);
 	if (gre_proto[version])
@@ -49,8 +54,11 @@ EXPORT_SYMBOL_GPL(gre_add_protocol);
 
 int gre_del_protocol(const struct gre_protocol *proto, u8 version)
 {
-	if (version >= GREPROTO_MAX)
-		goto err_out;
+	if (version >= GREPROTO_NONSTD_BASE && version < GREPROTO_NONSTD_MAX)
+		version -= GREPROTO_NONSTD_BASE - GREPROTO_MAX;
+	else
+		if (version >= GREPROTO_MAX)
+			goto err_out;
 
 	spin_lock(&gre_proto_lock);
 	if (rcu_dereference_protected(gre_proto[version],
@@ -74,12 +82,22 @@ static int gre_rcv(struct sk_buff *skb)
 	u8 ver;
 	int ret;
 
+	/* the standard GRE header is 12 octets; the EOIP header is 8
+	 * 4 octets long ethernet packet can not be valid
+	 */
 	if (!pskb_may_pull(skb, 12))
 		goto drop;
 
-	ver = skb->data[1]&0x7f;
-	if (ver >= GREPROTO_MAX)
-		goto drop;
+	/* check for custom EOIP header */
+	if (skb->data[0] == 0x20 && skb->data[1] == 0x01 &&
+			skb->data[2] == 0x64 && skb->data[3] == 0x00)
+		ver = GREPROTO_NONSTD_EOIP - GREPROTO_NONSTD_BASE
+				+ GREPROTO_MAX;
+	else {
+		ver = skb->data[1]&0x7f;
+		if (ver >= GREPROTO_MAX)
+			goto drop;
+	}
 
 	rcu_read_lock();
 	proto = rcu_dereference(gre_proto[ver]);
@@ -100,10 +118,19 @@ static void gre_err(struct sk_buff *skb, u32 info)
 {
 	const struct gre_protocol *proto;
 	const struct iphdr *iph = (const struct iphdr *)skb->data;
-	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+	u8 ver;
 
-	if (ver >= GREPROTO_MAX)
-		return;
+	if (skb->data[(iph->ihl<<2) + 0] == 0x20 &&
+			skb->data[(iph->ihl<<2) + 1] == 0x01 &&
+			skb->data[(iph->ihl<<2) + 2] == 0x64 &&
+			skb->data[(iph->ihl<<2) + 3] == 0x00)
+		ver = GREPROTO_NONSTD_EOIP - GREPROTO_NONSTD_BASE
+				+ GREPROTO_MAX;
+	else {
+		ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+		if (ver >= GREPROTO_MAX)
+			return;
+	}
 
 	rcu_read_lock();
 	proto = rcu_dereference(gre_proto[ver]);