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>

3 files changed, 163 insertions, 0 deletions

diff --git a/net/ife/Kconfig b/net/ife/Kconfig
new file mode 100644
index 000000000000..31e48b652c7c
--- /dev/null
+++ b/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.
diff --git a/net/ife/Makefile b/net/ife/Makefile
new file mode 100644
index 000000000000..2a90d97746cc
--- /dev/null
+++ b/net/ife/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the IFE encapsulation protocol
+#
+
+obj-$(CONFIG_NET_IFE) += ife.o
diff --git a/net/ife/ife.c b/net/ife/ife.c
new file mode 100644
index 000000000000..f360341c72eb
--- /dev/null
+++ b/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");