net/ife/ife.c

0001 /*
0002  * net/ife/ife.c - Inter-FE protocol based on ForCES WG InterFE LFB
0003  * Copyright (c) 2015 Jamal Hadi Salim <jhs@mojatatu.com>
0004  * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
0005  *
0006  * Refer to: draft-ietf-forces-interfelfb-03 and netdev01 paper:
0007  * "Distributing Linux Traffic Control Classifier-Action Subsystem"
0008  * Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
0009  *
0010  * This program is free software; you can redistribute it and/or modify
0011  * it under the terms of the GNU General Public License as published by
0012  * the Free Software Foundation.
0013  */
0014
0015 #include <linux/types.h>
0016 #include <linux/kernel.h>
0017 #include <linux/string.h>
0018 #include <linux/errno.h>
0019 #include <linux/skbuff.h>
0020 #include <linux/rtnetlink.h>
0021 #include <linux/module.h>
0022 #include <linux/init.h>
0023 #include <net/net_namespace.h>
0024 #include <net/netlink.h>
0025 #include <net/pkt_sched.h>
0026 #include <linux/etherdevice.h>
0027 #include <net/ife.h>
0028
0029 struct ifeheadr {
0030     __be16 metalen;
0031     u8 tlv_data[];
0032 };
0033
0034 void *ife_encode(struct sk_buff *skb, u16 metalen)
0035 {
0036     /* OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
0037      * where ORIGDATA = original ethernet header ...
0038      */
0039     int hdrm = metalen + IFE_METAHDRLEN;
0040     int total_push = hdrm + skb->dev->hard_header_len;
0041     struct ifeheadr *ifehdr;
0042     struct ethhdr *iethh;   /* inner ether header */
0043     int skboff = 0;
0044     int err;
0045
0046     err = skb_cow_head(skb, total_push);
0047     if (unlikely(err))
0048         return NULL;
0049
0050     iethh = (struct ethhdr *) skb->data;
0051
0052     __skb_push(skb, total_push);
0053     memcpy(skb->data, iethh, skb->dev->hard_header_len);
0054     skb_reset_mac_header(skb);
0055     skboff += skb->dev->hard_header_len;
0056
0057     /* total metadata length */
0058     ifehdr = (struct ifeheadr *) (skb->data + skboff);
0059     metalen += IFE_METAHDRLEN;
0060     ifehdr->metalen = htons(metalen);
0061
0062     return ifehdr->tlv_data;
0063 }
0064 EXPORT_SYMBOL_GPL(ife_encode);
0065
0066 void *ife_decode(struct sk_buff *skb, u16 *metalen)
0067 {
0068     struct ifeheadr *ifehdr;
0069     int total_pull;
0070     u16 ifehdrln;
0071
0072     if (!pskb_may_pull(skb, skb->dev->hard_header_len + IFE_METAHDRLEN))
0073         return NULL;
0074
0075     ifehdr = (struct ifeheadr *) (skb->data + skb->dev->hard_header_len);
0076     ifehdrln = ntohs(ifehdr->metalen);
0077     total_pull = skb->dev->hard_header_len + ifehdrln;
0078
0079     if (unlikely(ifehdrln < 2))
0080         return NULL;
0081
0082     if (unlikely(!pskb_may_pull(skb, total_pull)))
0083         return NULL;
0084
0085     skb_set_mac_header(skb, total_pull);
0086     __skb_pull(skb, total_pull);
0087     *metalen = ifehdrln - IFE_METAHDRLEN;
0088
0089     return &ifehdr->tlv_data;
0090 }
0091 EXPORT_SYMBOL_GPL(ife_decode);
0092
0093 struct meta_tlvhdr {
0094     __be16 type;
0095     __be16 len;
0096 };
0097
0098 static bool __ife_tlv_meta_valid(const unsigned char *skbdata,
0099                  const unsigned char *ifehdr_end)
0100 {
0101     const struct meta_tlvhdr *tlv;
0102     u16 tlvlen;
0103
0104     if (unlikely(skbdata + sizeof(*tlv) > ifehdr_end))
0105         return false;
0106
0107     tlv = (const struct meta_tlvhdr *)skbdata;
0108     tlvlen = ntohs(tlv->len);
0109
0110     /* tlv length field is inc header, check on minimum */
0111     if (tlvlen < NLA_HDRLEN)
0112         return false;
0113
0114     /* overflow by NLA_ALIGN check */
0115     if (NLA_ALIGN(tlvlen) < tlvlen)
0116         return false;
0117
0118     if (unlikely(skbdata + NLA_ALIGN(tlvlen) > ifehdr_end))
0119         return false;
0120
0121     return true;
0122 }
0123
0124 /* Caller takes care of presenting data in network order
0125  */
0126 void *ife_tlv_meta_decode(void *skbdata, const void *ifehdr_end, u16 *attrtype,
0127               u16 *dlen, u16 *totlen)
0128 {
0129     struct meta_tlvhdr *tlv;
0130
0131     if (!__ife_tlv_meta_valid(skbdata, ifehdr_end))
0132         return NULL;
0133
0134     tlv = (struct meta_tlvhdr *)skbdata;
0135     *dlen = ntohs(tlv->len) - NLA_HDRLEN;
0136     *attrtype = ntohs(tlv->type);
0137
0138     if (totlen)
0139         *totlen = nla_total_size(*dlen);
0140
0141     return skbdata + sizeof(struct meta_tlvhdr);
0142 }
0143 EXPORT_SYMBOL_GPL(ife_tlv_meta_decode);
0144
0145 void *ife_tlv_meta_next(void *skbdata)
0146 {
0147     struct meta_tlvhdr *tlv = (struct meta_tlvhdr *) skbdata;
0148     u16 tlvlen = ntohs(tlv->len);
0149
0150     tlvlen = NLA_ALIGN(tlvlen);
0151
0152     return skbdata + tlvlen;
0153 }
0154 EXPORT_SYMBOL_GPL(ife_tlv_meta_next);
0155
0156 /* Caller takes care of presenting data in network order
0157  */
0158 int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
0159 {
0160     __be32 *tlv = (__be32 *) (skbdata);
0161     u16 totlen = nla_total_size(dlen);  /*alignment + hdr */
0162     char *dptr = (char *) tlv + NLA_HDRLEN;
0163     u32 htlv = attrtype << 16 | (dlen + NLA_HDRLEN);
0164
0165     *tlv = htonl(htlv);
0166     memset(dptr, 0, totlen - NLA_HDRLEN);
0167     memcpy(dptr, dval, dlen);
0168
0169     return totlen;
0170 }
0171 EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
0172
0173 MODULE_AUTHOR("Jamal Hadi Salim <jhs@mojatatu.com>");
0174 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
0175 MODULE_DESCRIPTION("Inter-FE LFB action");
0176 MODULE_LICENSE("GPL");