1/*
2 * net/ife/ife.c - Inter-FE protocol based on ForCES WG InterFE LFB
3 * Copyright (c) 2015 Jamal Hadi Salim <jhs@mojatatu.com>
4 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
5 *
6 * Refer to: draft-ietf-forces-interfelfb-03 and netdev01 paper:
7 * "Distributing Linux Traffic Control Classifier-Action Subsystem"
8 * Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation.
13 */
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/string.h>
18#include <linux/errno.h>
19#include <linux/skbuff.h>
20#include <linux/rtnetlink.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <net/net_namespace.h>
24#include <net/netlink.h>
25#include <net/pkt_sched.h>
26#include <linux/etherdevice.h>
27#include <net/ife.h>
28
29struct ifeheadr {
30	__be16 metalen;
31	u8 tlv_data[];
32};
33
34void *ife_encode(struct sk_buff *skb, u16 metalen)
35{
36	/* OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
37	 * where ORIGDATA = original ethernet header ...
38	 */
39	int hdrm = metalen + IFE_METAHDRLEN;
40	int total_push = hdrm + skb->dev->hard_header_len;
41	struct ifeheadr *ifehdr;
42	struct ethhdr *iethh;	/* inner ether header */
43	int skboff = 0;
44	int err;
45
46	err = skb_cow_head(skb, total_push);
47	if (unlikely(err))
48		return NULL;
49
50	iethh = (struct ethhdr *) skb->data;
51
52	__skb_push(skb, total_push);
53	memcpy(skb->data, iethh, skb->dev->hard_header_len);
54	skb_reset_mac_header(skb);
55	skboff += skb->dev->hard_header_len;
56
57	/* total metadata length */
58	ifehdr = (struct ifeheadr *) (skb->data + skboff);
59	metalen += IFE_METAHDRLEN;
60	ifehdr->metalen = htons(metalen);
61
62	return ifehdr->tlv_data;
63}
64EXPORT_SYMBOL_GPL(ife_encode);
65
66void *ife_decode(struct sk_buff *skb, u16 *metalen)
67{
68	struct ifeheadr *ifehdr;
69	int total_pull;
70	u16 ifehdrln;
71
72	if (!pskb_may_pull(skb, skb->dev->hard_header_len + IFE_METAHDRLEN))
73		return NULL;
74
75	ifehdr = (struct ifeheadr *) (skb->data + skb->dev->hard_header_len);
76	ifehdrln = ntohs(ifehdr->metalen);
77	total_pull = skb->dev->hard_header_len + ifehdrln;
78
79	if (unlikely(ifehdrln < 2))
80		return NULL;
81
82	if (unlikely(!pskb_may_pull(skb, total_pull)))
83		return NULL;
84
85	ifehdr = (struct ifeheadr *)(skb->data + skb->dev->hard_header_len);
86	skb_set_mac_header(skb, total_pull);
87	__skb_pull(skb, total_pull);
88	*metalen = ifehdrln - IFE_METAHDRLEN;
89
90	return &ifehdr->tlv_data;
91}
92EXPORT_SYMBOL_GPL(ife_decode);
93
94struct meta_tlvhdr {
95	__be16 type;
96	__be16 len;
97};
98
99static bool __ife_tlv_meta_valid(const unsigned char *skbdata,
100				 const unsigned char *ifehdr_end)
101{
102	const struct meta_tlvhdr *tlv;
103	u16 tlvlen;
104
105	if (unlikely(skbdata + sizeof(*tlv) > ifehdr_end))
106		return false;
107
108	tlv = (const struct meta_tlvhdr *)skbdata;
109	tlvlen = ntohs(tlv->len);
110
111	/* tlv length field is inc header, check on minimum */
112	if (tlvlen < NLA_HDRLEN)
113		return false;
114
115	/* overflow by NLA_ALIGN check */
116	if (NLA_ALIGN(tlvlen) < tlvlen)
117		return false;
118
119	if (unlikely(skbdata + NLA_ALIGN(tlvlen) > ifehdr_end))
120		return false;
121
122	return true;
123}
124
125/* Caller takes care of presenting data in network order
126 */
127void *ife_tlv_meta_decode(void *skbdata, const void *ifehdr_end, u16 *attrtype,
128			  u16 *dlen, u16 *totlen)
129{
130	struct meta_tlvhdr *tlv;
131
132	if (!__ife_tlv_meta_valid(skbdata, ifehdr_end))
133		return NULL;
134
135	tlv = (struct meta_tlvhdr *)skbdata;
136	*dlen = ntohs(tlv->len) - NLA_HDRLEN;
137	*attrtype = ntohs(tlv->type);
138
139	if (totlen)
140		*totlen = nla_total_size(*dlen);
141
142	return skbdata + sizeof(struct meta_tlvhdr);
143}
144EXPORT_SYMBOL_GPL(ife_tlv_meta_decode);
145
146void *ife_tlv_meta_next(void *skbdata)
147{
148	struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata;
149	u16 tlvlen = ntohs(tlv->len);
150
151	tlvlen = NLA_ALIGN(tlvlen);
152
153	return skbdata + tlvlen;
154}
155EXPORT_SYMBOL_GPL(ife_tlv_meta_next);
156
157/* Caller takes care of presenting data in network order
158 */
159int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
160{
161	__be32 *tlv = (__be32 *) (skbdata);
162	u16 totlen = nla_total_size(dlen);	/*alignment + hdr */
163	char *dptr = (char *) tlv + NLA_HDRLEN;
164	u32 htlv = attrtype << 16 | (dlen + NLA_HDRLEN);
165
166	*tlv = htonl(htlv);
167	memset(dptr, 0, totlen - NLA_HDRLEN);
168	memcpy(dptr, dval, dlen);
169
170	return totlen;
171}
172EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
173
174MODULE_AUTHOR("Jamal Hadi Salim <jhs@mojatatu.com>");
175MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
176MODULE_DESCRIPTION("Inter-FE LFB action");
177MODULE_LICENSE("GPL");
178