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 322