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
ife_encode(struct sk_buff * skb,u16 metalen)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
ife_decode(struct sk_buff * skb,u16 * metalen)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 skb_set_mac_header(skb, total_pull);
86 __skb_pull(skb, total_pull);
87 *metalen = ifehdrln - IFE_METAHDRLEN;
88
89 return &ifehdr->tlv_data;
90 }
91 EXPORT_SYMBOL_GPL(ife_decode);
92
93 struct meta_tlvhdr {
94 __be16 type;
95 __be16 len;
96 };
97
__ife_tlv_meta_valid(const unsigned char * skbdata,const unsigned char * ifehdr_end)98 static bool __ife_tlv_meta_valid(const unsigned char *skbdata,
99 const unsigned char *ifehdr_end)
100 {
101 const struct meta_tlvhdr *tlv;
102 u16 tlvlen;
103
104 if (unlikely(skbdata + sizeof(*tlv) > ifehdr_end))
105 return false;
106
107 tlv = (const struct meta_tlvhdr *)skbdata;
108 tlvlen = ntohs(tlv->len);
109
110 /* tlv length field is inc header, check on minimum */
111 if (tlvlen < NLA_HDRLEN)
112 return false;
113
114 /* overflow by NLA_ALIGN check */
115 if (NLA_ALIGN(tlvlen) < tlvlen)
116 return false;
117
118 if (unlikely(skbdata + NLA_ALIGN(tlvlen) > ifehdr_end))
119 return false;
120
121 return true;
122 }
123
124 /* Caller takes care of presenting data in network order
125 */
ife_tlv_meta_decode(void * skbdata,const void * ifehdr_end,u16 * attrtype,u16 * dlen,u16 * totlen)126 void *ife_tlv_meta_decode(void *skbdata, const void *ifehdr_end, u16 *attrtype,
127 u16 *dlen, u16 *totlen)
128 {
129 struct meta_tlvhdr *tlv;
130
131 if (!__ife_tlv_meta_valid(skbdata, ifehdr_end))
132 return NULL;
133
134 tlv = (struct meta_tlvhdr *)skbdata;
135 *dlen = ntohs(tlv->len) - NLA_HDRLEN;
136 *attrtype = ntohs(tlv->type);
137
138 if (totlen)
139 *totlen = nla_total_size(*dlen);
140
141 return skbdata + sizeof(struct meta_tlvhdr);
142 }
143 EXPORT_SYMBOL_GPL(ife_tlv_meta_decode);
144
ife_tlv_meta_next(void * skbdata)145 void *ife_tlv_meta_next(void *skbdata)
146 {
147 struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata;
148 u16 tlvlen = ntohs(tlv->len);
149
150 tlvlen = NLA_ALIGN(tlvlen);
151
152 return skbdata + tlvlen;
153 }
154 EXPORT_SYMBOL_GPL(ife_tlv_meta_next);
155
156 /* Caller takes care of presenting data in network order
157 */
ife_tlv_meta_encode(void * skbdata,u16 attrtype,u16 dlen,const void * dval)158 int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
159 {
160 __be32 *tlv = (__be32 *) (skbdata);
161 u16 totlen = nla_total_size(dlen); /*alignment + hdr */
162 char *dptr = (char *) tlv + NLA_HDRLEN;
163 u32 htlv = attrtype << 16 | (dlen + NLA_HDRLEN);
164
165 *tlv = htonl(htlv);
166 memset(dptr, 0, totlen - NLA_HDRLEN);
167 memcpy(dptr, dval, dlen);
168
169 return totlen;
170 }
171 EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
172
173 MODULE_AUTHOR("Jamal Hadi Salim <jhs@mojatatu.com>");
174 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
175 MODULE_DESCRIPTION("Inter-FE LFB action");
176 MODULE_LICENSE("GPL");
177