net: Introduce ife encapsulation module

This module is responsible for the ife encapsulation protocol
encode/decode logics. That module can:
 - ife_encode: encode skb and reserve space for the ife meta header
 - ife_decode: decode skb and extract the meta header size
 - ife_tlv_meta_encode - encodes one tlv entry into the reserved ife
   header space.
 - ife_tlv_meta_decode - decodes one tlv entry from the packet
 - ife_tlv_meta_next - advance to the next tlv

Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -6250,6 +6250,13 @@ F:	include/net/cfg802154.h
 F:	include/net/ieee802154_netdev.h
 F:	Documentation/networking/ieee802154.txt
 
+IFE PROTOCOL
+M:	Yotam Gigi <yotamg@mellanox.com>
+M:	Jamal Hadi Salim <jhs@mojatatu.com>
+F:	net/ife
+F:	include/net/ife.h
+F:	include/uapi/linux/ife.h
+
 IGORPLUG-USB IR RECEIVER
 M:	Sean Young <sean@mess.org>
 L:	linux-media@vger.kernel.org

include/net/ife.h

@@ -0,0 +1,51 @@
+#ifndef __NET_IFE_H
+#define __NET_IFE_H
+
+#include <linux/etherdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/module.h>
+#include <uapi/linux/ife.h>
+
+#if IS_ENABLED(CONFIG_NET_IFE)
+
+void *ife_encode(struct sk_buff *skb, u16 metalen);
+void *ife_decode(struct sk_buff *skb, u16 *metalen);
+
+void *ife_tlv_meta_decode(void *skbdata, u16 *attrtype, u16 *dlen, u16 *totlen);
+int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen,
+			const void *dval);
+
+void *ife_tlv_meta_next(void *skbdata);
+
+#else
+
+static inline void *ife_encode(struct sk_buff *skb, u16 metalen)
+{
+	return NULL;
+}
+
+static inline void *ife_decode(struct sk_buff *skb, u16 *metalen)
+{
+	return NULL;
+}
+
+static inline void *ife_tlv_meta_decode(void *skbdata, u16 *attrtype, u16 *dlen,
+					u16 *totlen)
+{
+	return NULL;
+}
+
+static inline int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen,
+			const void *dval)
+{
+	return 0;
+}
+
+static inline void *ife_tlv_meta_next(void *skbdata)
+{
+	return NULL;
+}
+
+#endif
+
+#endif /* __NET_IFE_H */

include/uapi/linux/Kbuild

@@ -195,6 +195,7 @@ header-y += if_tun.h
 header-y += if_tunnel.h
 header-y += if_vlan.h
 header-y += if_x25.h
+header-y += ife.h
 header-y += igmp.h
 header-y += ila.h
 header-y += in6.h

include/uapi/linux/ife.h

@@ -0,0 +1,18 @@
+#ifndef __UAPI_IFE_H
+#define __UAPI_IFE_H
+
+#define IFE_METAHDRLEN 2
+
+enum {
+	IFE_META_SKBMARK = 1,
+	IFE_META_HASHID,
+	IFE_META_PRIO,
+	IFE_META_QMAP,
+	IFE_META_TCINDEX,
+	__IFE_META_MAX
+};
+
+/*Can be overridden at runtime by module option*/
+#define IFE_META_MAX (__IFE_META_MAX - 1)
+
+#endif

net/Kconfig

@@ -391,6 +391,7 @@ source "net/caif/Kconfig"
 source "net/ceph/Kconfig"
 source "net/nfc/Kconfig"
 source "net/psample/Kconfig"
+source "net/ife/Kconfig"
 
 config LWTUNNEL
 	bool "Network light weight tunnels"

net/Makefile

@@ -71,6 +71,7 @@ obj-$(CONFIG_CEPH_LIB)		+= ceph/
 obj-$(CONFIG_BATMAN_ADV)	+= batman-adv/
 obj-$(CONFIG_NFC)		+= nfc/
 obj-$(CONFIG_PSAMPLE)		+= psample/
+obj-$(CONFIG_NET_IFE)		+= ife/
 obj-$(CONFIG_OPENVSWITCH)	+= openvswitch/
 obj-$(CONFIG_VSOCKETS)	+= vmw_vsock/
 obj-$(CONFIG_MPLS)		+= mpls/

net/ife/Kconfig

@@ -0,0 +1,16 @@
+#
+# IFE subsystem configuration
+#
+
+menuconfig NET_IFE
+	depends on NET
+        tristate "Inter-FE based on IETF ForCES InterFE LFB"
+	default n
+	help
+	  Say Y here to add support of IFE encapsulation protocol
+	  For details refer to netdev01 paper:
+	  "Distributing Linux Traffic Control Classifier-Action Subsystem"
+	   Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
+
+	  To compile this support as a module, choose M here: the module will
+	  be called ife.

net/ife/Makefile

@@ -0,0 +1,5 @@
+#
+# Makefile for the IFE encapsulation protocol
+#
+
+obj-$(CONFIG_NET_IFE) += ife.o

net/ife/ife.c

@@ -0,0 +1,142 @@
+/*
+ * net/ife/ife.c - Inter-FE protocol based on ForCES WG InterFE LFB
+ * Copyright (c) 2015 Jamal Hadi Salim <jhs@mojatatu.com>
+ * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
+ *
+ * Refer to: draft-ietf-forces-interfelfb-03 and netdev01 paper:
+ * "Distributing Linux Traffic Control Classifier-Action Subsystem"
+ * Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <net/net_namespace.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <linux/etherdevice.h>
+#include <net/ife.h>
+
+struct ifeheadr {
+	__be16 metalen;
+	u8 tlv_data[];
+};
+
+void *ife_encode(struct sk_buff *skb, u16 metalen)
+{
+	/* OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
+	 * where ORIGDATA = original ethernet header ...
+	 */
+	int hdrm = metalen + IFE_METAHDRLEN;
+	int total_push = hdrm + skb->dev->hard_header_len;
+	struct ifeheadr *ifehdr;
+	struct ethhdr *iethh;	/* inner ether header */
+	int skboff = 0;
+	int err;
+
+	err = skb_cow_head(skb, total_push);
+	if (unlikely(err))
+		return NULL;
+
+	iethh = (struct ethhdr *) skb->data;
+
+	__skb_push(skb, total_push);
+	memcpy(skb->data, iethh, skb->dev->hard_header_len);
+	skb_reset_mac_header(skb);
+	skboff += skb->dev->hard_header_len;
+
+	/* total metadata length */
+	ifehdr = (struct ifeheadr *) (skb->data + skboff);
+	metalen += IFE_METAHDRLEN;
+	ifehdr->metalen = htons(metalen);
+
+	return ifehdr->tlv_data;
+}
+EXPORT_SYMBOL_GPL(ife_encode);
+
+void *ife_decode(struct sk_buff *skb, u16 *metalen)
+{
+	struct ifeheadr *ifehdr;
+	int total_pull;
+	u16 ifehdrln;
+
+	ifehdr = (struct ifeheadr *) (skb->data + skb->dev->hard_header_len);
+	ifehdrln = ntohs(ifehdr->metalen);
+	total_pull = skb->dev->hard_header_len + ifehdrln;
+
+	if (unlikely(ifehdrln < 2))
+		return NULL;
+
+	if (unlikely(!pskb_may_pull(skb, total_pull)))
+		return NULL;
+
+	skb_set_mac_header(skb, total_pull);
+	__skb_pull(skb, total_pull);
+	*metalen = ifehdrln - IFE_METAHDRLEN;
+
+	return &ifehdr->tlv_data;
+}
+EXPORT_SYMBOL_GPL(ife_decode);
+
+struct meta_tlvhdr {
+	__be16 type;
+	__be16 len;
+};
+
+/* Caller takes care of presenting data in network order
+ */
+void *ife_tlv_meta_decode(void *skbdata, u16 *attrtype, u16 *dlen, u16 *totlen)
+{
+	struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata;
+
+	*dlen = ntohs(tlv->len) - NLA_HDRLEN;
+	*attrtype = ntohs(tlv->type);
+
+	if (totlen)
+		*totlen = nla_total_size(*dlen);
+
+	return skbdata + sizeof(struct meta_tlvhdr);
+}
+EXPORT_SYMBOL_GPL(ife_tlv_meta_decode);
+
+void *ife_tlv_meta_next(void *skbdata)
+{
+	struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata;
+	u16 tlvlen = ntohs(tlv->len);
+
+	tlvlen = NLA_ALIGN(tlvlen);
+
+	return skbdata + tlvlen;
+}
+EXPORT_SYMBOL_GPL(ife_tlv_meta_next);
+
+/* Caller takes care of presenting data in network order
+ */
+int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
+{
+	__be32 *tlv = (__be32 *) (skbdata);
+	u16 totlen = nla_total_size(dlen);	/*alignment + hdr */
+	char *dptr = (char *) tlv + NLA_HDRLEN;
+	u32 htlv = attrtype << 16 | (dlen + NLA_HDRLEN);
+
+	*tlv = htonl(htlv);
+	memset(dptr, 0, totlen - NLA_HDRLEN);
+	memcpy(dptr, dval, dlen);
+
+	return totlen;
+}
+EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
+
+MODULE_AUTHOR("Jamal Hadi Salim <jhs@mojatatu.com>");
+MODULE_AUTHOR("Yotam Gigi <yotamg@mellanox.com>");
+MODULE_DESCRIPTION("Inter-FE LFB action");
+MODULE_LICENSE("GPL");