include/net/erspan.h

   1 #ifndef __LINUX_ERSPAN_H
   2 #define __LINUX_ERSPAN_H
   3
   4 /*
   5  * GRE header for ERSPAN type I encapsulation (4 octets [34:37])
   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|0|0|00000|000000000|00000|    Protocol Type for ERSPAN   |
  10  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  11  *
  12  *  The Type I ERSPAN frame format is based on the barebones IP + GRE
  13  *  encapsulation (as described above) on top of the raw mirrored frame.
  14  *  There is no extra ERSPAN header.
  15  *
  16  *
  17  * GRE header for ERSPAN type II and II encapsulation (8 octets [34:41])
  18  *       0                   1                   2                   3
  19  *      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
  20  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  21  *     |0|0|0|1|0|00000|000000000|00000|    Protocol Type for ERSPAN   |
  22  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  23  *     |      Sequence Number (increments per packet per session)      |
  24  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  25  *
  26  *  Note that in the above GRE header [RFC1701] out of the C, R, K, S,
  27  *  s, Recur, Flags, Version fields only S (bit 03) is set to 1. The
  28  *  other fields are set to zero, so only a sequence number follows.
  29  *
  30  *  ERSPAN Version 1 (Type II) header (8 octets [42:49])
  31  *  0                   1                   2                   3
  32  *  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
  33  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  34  * |  Ver  |          VLAN         | COS | En|T|    Session ID     |
  35  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  36  * |      Reserved         |                  Index                |
  37  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  38  *
  39  *
  40  *  ERSPAN Version 2 (Type III) header (12 octets [42:49])
  41  *  0                   1                   2                   3
  42  *  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
  43  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  44  * |  Ver  |          VLAN         | COS |BSO|T|     Session ID    |
  45  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  46  * |                          Timestamp                            |
  47  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  48  * |             SGT               |P|    FT   |   Hw ID   |D|Gra|O|
  49  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  50  *
  51  *      Platform Specific SubHeader (8 octets, optional)
  52  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  53  * |  Platf ID |               Platform Specific Info              |
  54  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  55  * |                  Platform Specific Info                       |
  56  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  57  *
  58  * GRE proto ERSPAN type I/II = 0x88BE, type III = 0x22EB
  59  */
  60
  61 #include <linux/ip.h>
  62 #include <linux/ipv6.h>
  63 #include <linux/skbuff.h>
  64 #include <uapi/linux/erspan.h>
  65
  66 #define ERSPAN_VERSION  0x1     /* ERSPAN type II */
  67 #define VER_MASK        0xf000
  68 #define VLAN_MASK       0x0fff
  69 #define COS_MASK        0xe000
  70 #define EN_MASK         0x1800
  71 #define T_MASK          0x0400
  72 #define ID_MASK         0x03ff
  73 #define INDEX_MASK      0xfffff
  74
  75 #define ERSPAN_VERSION2 0x2     /* ERSPAN type III*/
  76 #define BSO_MASK        EN_MASK
  77 #define SGT_MASK        0xffff0000
  78 #define P_MASK          0x8000
  79 #define FT_MASK         0x7c00
  80 #define HWID_MASK       0x03f0
  81 #define DIR_MASK        0x0008
  82 #define GRA_MASK        0x0006
  83 #define O_MASK          0x0001
  84
  85 #define HWID_OFFSET    4
  86 #define DIR_OFFSET     3
  87
  88 enum erspan_encap_type {
  89         ERSPAN_ENCAP_NOVLAN = 0x0,      /* originally without VLAN tag */
  90         ERSPAN_ENCAP_ISL = 0x1,         /* originally ISL encapsulated */
  91         ERSPAN_ENCAP_8021Q = 0x2,       /* originally 802.1Q encapsulated */
  92         ERSPAN_ENCAP_INFRAME = 0x3,     /* VLAN tag perserved in frame */
  93 };
  94
  95 #define ERSPAN_V1_MDSIZE        4
  96 #define ERSPAN_V2_MDSIZE        8
  97
  98 struct erspan_base_hdr {
  99 #if defined(__LITTLE_ENDIAN_BITFIELD)
 100         __u8    vlan_upper:4,
 101                 ver:4;
 102         __u8    vlan:8;
 103         __u8    session_id_upper:2,
 104                 t:1,
 105                 en:2,
 106                 cos:3;
 107         __u8    session_id:8;
 108 #elif defined(__BIG_ENDIAN_BITFIELD)
 109         __u8    ver: 4,
 110                 vlan_upper:4;
 111         __u8    vlan:8;
 112         __u8    cos:3,
 113                 en:2,
 114                 t:1,
 115                 session_id_upper:2;
 116         __u8    session_id:8;
 117 #else
 118 #error "Please fix <asm/byteorder.h>"
 119 #endif
 120 };
 121
 122 static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
 123 {
 124         ershdr->session_id = id & 0xff;
 125         ershdr->session_id_upper = (id >> 8) & 0x3;
 126 }
 127
 128 static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
 129 {
 130         return (ershdr->session_id_upper << 8) + ershdr->session_id;
 131 }
 132
 133 static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
 134 {
 135         ershdr->vlan = vlan & 0xff;
 136         ershdr->vlan_upper = (vlan >> 8) & 0xf;
 137 }
 138
 139 static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
 140 {
 141         return (ershdr->vlan_upper << 8) + ershdr->vlan;
 142 }
 143
 144 static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
 145 {
 146         md2->hwid = hwid & 0xf;
 147         md2->hwid_upper = (hwid >> 4) & 0x3;
 148 }
 149
 150 static inline u8 get_hwid(const struct erspan_md2 *md2)
 151 {
 152         return (md2->hwid_upper << 4) + md2->hwid;
 153 }
 154
 155 static inline int erspan_hdr_len(int version)
 156 {
 157         if (version == 0)
 158                 return 0;
 159
 160         return sizeof(struct erspan_base_hdr) +
 161                (version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
 162 }
 163
 164 static inline u8 tos_to_cos(u8 tos)
 165 {
 166         u8 dscp, cos;
 167
 168         dscp = tos >> 2;
 169         cos = dscp >> 3;
 170         return cos;
 171 }
 172
 173 static inline void erspan_build_header(struct sk_buff *skb,
 174                                 u32 id, u32 index,
 175                                 bool truncate, bool is_ipv4)
 176 {
 177         struct ethhdr *eth = (struct ethhdr *)skb->data;
 178         enum erspan_encap_type enc_type;
 179         struct erspan_base_hdr *ershdr;
 180         struct qtag_prefix {
 181                 __be16 eth_type;
 182                 __be16 tci;
 183         } *qp;
 184         u16 vlan_tci = 0;
 185         u8 tos;
 186         __be32 *idx;
 187
 188         tos = is_ipv4 ? ip_hdr(skb)->tos :
 189                         (ipv6_hdr(skb)->priority << 4) +
 190                         (ipv6_hdr(skb)->flow_lbl[0] >> 4);
 191
 192         enc_type = ERSPAN_ENCAP_NOVLAN;
 193
 194         /* If mirrored packet has vlan tag, extract tci and
 195          *  perserve vlan header in the mirrored frame.
 196          */
 197         if (eth->h_proto == htons(ETH_P_8021Q)) {
 198                 qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
 199                 vlan_tci = ntohs(qp->tci);
 200                 enc_type = ERSPAN_ENCAP_INFRAME;
 201         }
 202
 203         skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
 204         ershdr = (struct erspan_base_hdr *)skb->data;
 205         memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
 206
 207         /* Build base header */
 208         ershdr->ver = ERSPAN_VERSION;
 209         ershdr->cos = tos_to_cos(tos);
 210         ershdr->en = enc_type;
 211         ershdr->t = truncate;
 212         set_vlan(ershdr, vlan_tci);
 213         set_session_id(ershdr, id);
 214
 215         /* Build metadata */
 216         idx = (__be32 *)(ershdr + 1);
 217         *idx = htonl(index & INDEX_MASK);
 218 }
 219
 220 /* ERSPAN GRA: timestamp granularity
 221  *   00b --> granularity = 100 microseconds
 222  *   01b --> granularity = 100 nanoseconds
 223  *   10b --> granularity = IEEE 1588
 224  * Here we only support 100 microseconds.
 225  */
 226 static inline __be32 erspan_get_timestamp(void)
 227 {
 228         u64 h_usecs;
 229         ktime_t kt;
 230
 231         kt = ktime_get_real();
 232         h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC);
 233
 234         /* ERSPAN base header only has 32-bit,
 235          * so it wraps around 4 days.
 236          */
 237         return htonl((u32)h_usecs);
 238 }
 239
 240 /* ERSPAN BSO (Bad/Short/Oversized), see RFC1757
 241  *   00b --> Good frame with no error, or unknown integrity
 242  *   01b --> Payload is a Short Frame
 243  *   10b --> Payload is an Oversized Frame
 244  *   11b --> Payload is a Bad Frame with CRC or Alignment Error
 245  */
 246 enum erspan_bso {
 247         BSO_NOERROR = 0x0,
 248         BSO_SHORT = 0x1,
 249         BSO_OVERSIZED = 0x2,
 250         BSO_BAD = 0x3,
 251 };
 252
 253 static inline u8 erspan_detect_bso(struct sk_buff *skb)
 254 {
 255         /* BSO_BAD is not handled because the frame CRC
 256          * or alignment error information is in FCS.
 257          */
 258         if (skb->len < ETH_ZLEN)
 259                 return BSO_SHORT;
 260
 261         if (skb->len > ETH_FRAME_LEN)
 262                 return BSO_OVERSIZED;
 263
 264         return BSO_NOERROR;
 265 }
 266
 267 static inline void erspan_build_header_v2(struct sk_buff *skb,
 268                                           u32 id, u8 direction, u16 hwid,
 269                                           bool truncate, bool is_ipv4)
 270 {
 271         struct ethhdr *eth = (struct ethhdr *)skb->data;
 272         struct erspan_base_hdr *ershdr;
 273         struct erspan_md2 *md2;
 274         struct qtag_prefix {
 275                 __be16 eth_type;
 276                 __be16 tci;
 277         } *qp;
 278         u16 vlan_tci = 0;
 279         u8 gra = 0; /* 100 usec */
 280         u8 bso = 0; /* Bad/Short/Oversized */
 281         u8 sgt = 0;
 282         u8 tos;
 283
 284         tos = is_ipv4 ? ip_hdr(skb)->tos :
 285                         (ipv6_hdr(skb)->priority << 4) +
 286                         (ipv6_hdr(skb)->flow_lbl[0] >> 4);
 287
 288         /* Unlike v1, v2 does not have En field,
 289          * so only extract vlan tci field.
 290          */
 291         if (eth->h_proto == htons(ETH_P_8021Q)) {
 292                 qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
 293                 vlan_tci = ntohs(qp->tci);
 294         }
 295
 296         bso = erspan_detect_bso(skb);
 297         skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
 298         ershdr = (struct erspan_base_hdr *)skb->data;
 299         memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
 300
 301         /* Build base header */
 302         ershdr->ver = ERSPAN_VERSION2;
 303         ershdr->cos = tos_to_cos(tos);
 304         ershdr->en = bso;
 305         ershdr->t = truncate;
 306         set_vlan(ershdr, vlan_tci);
 307         set_session_id(ershdr, id);
 308
 309         /* Build metadata */
 310         md2 = (struct erspan_md2 *)(ershdr + 1);
 311         md2->timestamp = erspan_get_timestamp();
 312         md2->sgt = htons(sgt);
 313         md2->p = 1;
 314         md2->ft = 0;
 315         md2->dir = direction;
 316         md2->gra = gra;
 317         md2->o = 0;
 318         set_hwid(md2, hwid);
 319 }
 320
 321 #endif