include/net/erspan.h

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This source file includes following definitions.
set_session_id
get_session_id
set_vlan
get_vlan
set_hwid
get_hwid
erspan_hdr_len
tos_to_cos
erspan_build_header
erspan_get_timestamp
erspan_detect_bso
erspan_build_header_v2
   1 #ifndef __LINUX_ERSPAN_H
   2 #define __LINUX_ERSPAN_H
   3 
   4 /*
   5  * GRE header for ERSPAN encapsulation (8 octets [34:41]) -- 8 bytes
   6  *       0                   1                   2                   3
   7  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   8  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   9  *     |0|0|0|1|0|00000|000000000|00000|    Protocol Type for ERSPAN   |
  10  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  11  *     |      Sequence Number (increments per packet per session)      |
  12  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  13  *
  14  *  Note that in the above GRE header [RFC1701] out of the C, R, K, S,
  15  *  s, Recur, Flags, Version fields only S (bit 03) is set to 1. The
  16  *  other fields are set to zero, so only a sequence number follows.
  17  *
  18  *  ERSPAN Version 1 (Type II) header (8 octets [42:49])
  19  *  0                   1                   2                   3
  20  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  21  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  22  * |  Ver  |          VLAN         | COS | En|T|    Session ID     |
  23  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  24  * |      Reserved         |                  Index                |
  25  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  26  *
  27  *
  28  *  ERSPAN Version 2 (Type III) header (12 octets [42:49])
  29  *  0                   1                   2                   3
  30  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  31  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  32  * |  Ver  |          VLAN         | COS |BSO|T|     Session ID    |
  33  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  34  * |                          Timestamp                            |
  35  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  36  * |             SGT               |P|    FT   |   Hw ID   |D|Gra|O|
  37  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  38  *
  39  *      Platform Specific SubHeader (8 octets, optional)
  40  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41  * |  Platf ID |               Platform Specific Info              |
  42  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  43  * |                  Platform Specific Info                       |
  44  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  45  *
  46  * GRE proto ERSPAN type II = 0x88BE, type III = 0x22EB
  47  */
  48 
  49 #include <uapi/linux/erspan.h>
  50 
  51 #define ERSPAN_VERSION  0x1     /* ERSPAN type II */
  52 #define VER_MASK        0xf000
  53 #define VLAN_MASK       0x0fff
  54 #define COS_MASK        0xe000
  55 #define EN_MASK         0x1800
  56 #define T_MASK          0x0400
  57 #define ID_MASK         0x03ff
  58 #define INDEX_MASK      0xfffff
  59 
  60 #define ERSPAN_VERSION2 0x2     /* ERSPAN type III*/
  61 #define BSO_MASK        EN_MASK
  62 #define SGT_MASK        0xffff0000
  63 #define P_MASK          0x8000
  64 #define FT_MASK         0x7c00
  65 #define HWID_MASK       0x03f0
  66 #define DIR_MASK        0x0008
  67 #define GRA_MASK        0x0006
  68 #define O_MASK          0x0001
  69 
  70 #define HWID_OFFSET    4
  71 #define DIR_OFFSET     3
  72 
  73 enum erspan_encap_type {
  74         ERSPAN_ENCAP_NOVLAN = 0x0,      /* originally without VLAN tag */
  75         ERSPAN_ENCAP_ISL = 0x1,         /* originally ISL encapsulated */
  76         ERSPAN_ENCAP_8021Q = 0x2,       /* originally 802.1Q encapsulated */
  77         ERSPAN_ENCAP_INFRAME = 0x3,     /* VLAN tag perserved in frame */
  78 };
  79 
  80 #define ERSPAN_V1_MDSIZE        4
  81 #define ERSPAN_V2_MDSIZE        8
  82 
  83 struct erspan_base_hdr {
  84 #if defined(__LITTLE_ENDIAN_BITFIELD)
  85         __u8    vlan_upper:4,
  86                 ver:4;
  87         __u8    vlan:8;
  88         __u8    session_id_upper:2,
  89                 t:1,
  90                 en:2,
  91                 cos:3;
  92         __u8    session_id:8;
  93 #elif defined(__BIG_ENDIAN_BITFIELD)
  94         __u8    ver: 4,
  95                 vlan_upper:4;
  96         __u8    vlan:8;
  97         __u8    cos:3,
  98                 en:2,
  99                 t:1,
 100                 session_id_upper:2;
 101         __u8    session_id:8;
 102 #else
 103 #error "Please fix <asm/byteorder.h>"
 104 #endif
 105 };
 106 
 107 static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
 108 {
 109         ershdr->session_id = id & 0xff;
 110         ershdr->session_id_upper = (id >> 8) & 0x3;
 111 }
 112 
 113 static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
 114 {
 115         return (ershdr->session_id_upper << 8) + ershdr->session_id;
 116 }
 117 
 118 static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
 119 {
 120         ershdr->vlan = vlan & 0xff;
 121         ershdr->vlan_upper = (vlan >> 8) & 0xf;
 122 }
 123 
 124 static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
 125 {
 126         return (ershdr->vlan_upper << 8) + ershdr->vlan;
 127 }
 128 
 129 static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
 130 {
 131         md2->hwid = hwid & 0xf;
 132         md2->hwid_upper = (hwid >> 4) & 0x3;
 133 }
 134 
 135 static inline u8 get_hwid(const struct erspan_md2 *md2)
 136 {
 137         return (md2->hwid_upper << 4) + md2->hwid;
 138 }
 139 
 140 static inline int erspan_hdr_len(int version)
 141 {
 142         return sizeof(struct erspan_base_hdr) +
 143                (version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
 144 }
 145 
 146 static inline u8 tos_to_cos(u8 tos)
 147 {
 148         u8 dscp, cos;
 149 
 150         dscp = tos >> 2;
 151         cos = dscp >> 3;
 152         return cos;
 153 }
 154 
 155 static inline void erspan_build_header(struct sk_buff *skb,
 156                                 u32 id, u32 index,
 157                                 bool truncate, bool is_ipv4)
 158 {
 159         struct ethhdr *eth = (struct ethhdr *)skb->data;
 160         enum erspan_encap_type enc_type;
 161         struct erspan_base_hdr *ershdr;
 162         struct qtag_prefix {
 163                 __be16 eth_type;
 164                 __be16 tci;
 165         } *qp;
 166         u16 vlan_tci = 0;
 167         u8 tos;
 168         __be32 *idx;
 169 
 170         tos = is_ipv4 ? ip_hdr(skb)->tos :
 171                         (ipv6_hdr(skb)->priority << 4) +
 172                         (ipv6_hdr(skb)->flow_lbl[0] >> 4);
 173 
 174         enc_type = ERSPAN_ENCAP_NOVLAN;
 175 
 176         /* If mirrored packet has vlan tag, extract tci and
 177          *  perserve vlan header in the mirrored frame.
 178          */
 179         if (eth->h_proto == htons(ETH_P_8021Q)) {
 180                 qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
 181                 vlan_tci = ntohs(qp->tci);
 182                 enc_type = ERSPAN_ENCAP_INFRAME;
 183         }
 184 
 185         skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
 186         ershdr = (struct erspan_base_hdr *)skb->data;
 187         memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
 188 
 189         /* Build base header */
 190         ershdr->ver = ERSPAN_VERSION;
 191         ershdr->cos = tos_to_cos(tos);
 192         ershdr->en = enc_type;
 193         ershdr->t = truncate;
 194         set_vlan(ershdr, vlan_tci);
 195         set_session_id(ershdr, id);
 196 
 197         /* Build metadata */
 198         idx = (__be32 *)(ershdr + 1);
 199         *idx = htonl(index & INDEX_MASK);
 200 }
 201 
 202 /* ERSPAN GRA: timestamp granularity
 203  *   00b --> granularity = 100 microseconds
 204  *   01b --> granularity = 100 nanoseconds
 205  *   10b --> granularity = IEEE 1588
 206  * Here we only support 100 microseconds.
 207  */
 208 static inline __be32 erspan_get_timestamp(void)
 209 {
 210         u64 h_usecs;
 211         ktime_t kt;
 212 
 213         kt = ktime_get_real();
 214         h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC);
 215 
 216         /* ERSPAN base header only has 32-bit,
 217          * so it wraps around 4 days.
 218          */
 219         return htonl((u32)h_usecs);
 220 }
 221 
 222 /* ERSPAN BSO (Bad/Short/Oversized), see RFC1757
 223  *   00b --> Good frame with no error, or unknown integrity
 224  *   01b --> Payload is a Short Frame
 225  *   10b --> Payload is an Oversized Frame
 226  *   11b --> Payload is a Bad Frame with CRC or Alignment Error
 227  */
 228 enum erspan_bso {
 229         BSO_NOERROR = 0x0,
 230         BSO_SHORT = 0x1,
 231         BSO_OVERSIZED = 0x2,
 232         BSO_BAD = 0x3,
 233 };
 234 
 235 static inline u8 erspan_detect_bso(struct sk_buff *skb)
 236 {
 237         /* BSO_BAD is not handled because the frame CRC
 238          * or alignment error information is in FCS.
 239          */
 240         if (skb->len < ETH_ZLEN)
 241                 return BSO_SHORT;
 242 
 243         if (skb->len > ETH_FRAME_LEN)
 244                 return BSO_OVERSIZED;
 245 
 246         return BSO_NOERROR;
 247 }
 248 
 249 static inline void erspan_build_header_v2(struct sk_buff *skb,
 250                                           u32 id, u8 direction, u16 hwid,
 251                                           bool truncate, bool is_ipv4)
 252 {
 253         struct ethhdr *eth = (struct ethhdr *)skb->data;
 254         struct erspan_base_hdr *ershdr;
 255         struct erspan_md2 *md2;
 256         struct qtag_prefix {
 257                 __be16 eth_type;
 258                 __be16 tci;
 259         } *qp;
 260         u16 vlan_tci = 0;
 261         u8 gra = 0; /* 100 usec */
 262         u8 bso = 0; /* Bad/Short/Oversized */
 263         u8 sgt = 0;
 264         u8 tos;
 265 
 266         tos = is_ipv4 ? ip_hdr(skb)->tos :
 267                         (ipv6_hdr(skb)->priority << 4) +
 268                         (ipv6_hdr(skb)->flow_lbl[0] >> 4);
 269 
 270         /* Unlike v1, v2 does not have En field,
 271          * so only extract vlan tci field.
 272          */
 273         if (eth->h_proto == htons(ETH_P_8021Q)) {
 274                 qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
 275                 vlan_tci = ntohs(qp->tci);
 276         }
 277 
 278         bso = erspan_detect_bso(skb);
 279         skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
 280         ershdr = (struct erspan_base_hdr *)skb->data;
 281         memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
 282 
 283         /* Build base header */
 284         ershdr->ver = ERSPAN_VERSION2;
 285         ershdr->cos = tos_to_cos(tos);
 286         ershdr->en = bso;
 287         ershdr->t = truncate;
 288         set_vlan(ershdr, vlan_tci);
 289         set_session_id(ershdr, id);
 290 
 291         /* Build metadata */
 292         md2 = (struct erspan_md2 *)(ershdr + 1);
 293         md2->timestamp = erspan_get_timestamp();
 294         md2->sgt = htons(sgt);
 295         md2->p = 1;
 296         md2->ft = 0;
 297         md2->dir = direction;
 298         md2->gra = gra;
 299         md2->o = 0;
 300         set_hwid(md2, hwid);
 301 }
 302 
 303 #endif
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root/include/net/erspan.h

INCLUDED FROM

DEFINITIONS
