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
29 struct ifeheadr {
30 __be16 metalen;
31 u8 tlv_data[];
32 };
33
34 void *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 }
64 EXPORT_SYMBOL_GPL(ife_encode);
65
66 void *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 }
92 EXPORT_SYMBOL_GPL(ife_decode);
93
94 struct meta_tlvhdr {
95 __be16 type;
96 __be16 len;
97 };
98
99 static 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 */
127 void *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 }
144 EXPORT_SYMBOL_GPL(ife_tlv_meta_decode);
145
146 void *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 }
155 EXPORT_SYMBOL_GPL(ife_tlv_meta_next);
156
157 /* Caller takes care of presenting data in network order
158 */
159 int 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 }
172 EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
173
174 MODULE_AUTHOR("Jamal Hadi Salim <jhs@mojatatu.com>");
175 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
176 MODULE_DESCRIPTION("Inter-FE LFB action");
177 MODULE_LICENSE("GPL");
178
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