include/net/llc_pdu.h

   1 #ifndef LLC_PDU_H
   2 #define LLC_PDU_H
   3 /*
   4  * Copyright (c) 1997 by Procom Technology,Inc.
   5  *               2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   6  *
   7  * This program can be redistributed or modified under the terms of the
   8  * GNU General Public License as published by the Free Software Foundation.
   9  * This program is distributed without any warranty or implied warranty
  10  * of merchantability or fitness for a particular purpose.
  11  *
  12  * See the GNU General Public License for more details.
  13  */
  14
  15 #include <linux/if_ether.h>
  16
  17 /* Lengths of frame formats */
  18 #define LLC_PDU_LEN_I           4       /* header and 2 control bytes */
  19 #define LLC_PDU_LEN_S           4
  20 #define LLC_PDU_LEN_U           3       /* header and 1 control byte */
  21 /* header and 1 control byte and XID info */
  22 #define LLC_PDU_LEN_U_XID       (LLC_PDU_LEN_U + sizeof(struct llc_xid_info))
  23 /* Known SAP addresses */
  24 #define LLC_GLOBAL_SAP  0xFF
  25 #define LLC_NULL_SAP    0x00    /* not network-layer visible */
  26 #define LLC_MGMT_INDIV  0x02    /* station LLC mgmt indiv addr */
  27 #define LLC_MGMT_GRP    0x03    /* station LLC mgmt group addr */
  28 #define LLC_RDE_SAP     0xA6    /* route ... */
  29
  30 /* SAP field bit masks */
  31 #define LLC_ISO_RESERVED_SAP    0x02
  32 #define LLC_SAP_GROUP_DSAP      0x01
  33 #define LLC_SAP_RESP_SSAP       0x01
  34
  35 /* Group/individual DSAP indicator is DSAP field */
  36 #define LLC_PDU_GROUP_DSAP_MASK    0x01
  37 #define LLC_PDU_IS_GROUP_DSAP(pdu)      \
  38         ((pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
  39 #define LLC_PDU_IS_INDIV_DSAP(pdu)      \
  40         (!(pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
  41
  42 /* Command/response PDU indicator in SSAP field */
  43 #define LLC_PDU_CMD_RSP_MASK    0x01
  44 #define LLC_PDU_CMD             0
  45 #define LLC_PDU_RSP             1
  46 #define LLC_PDU_IS_CMD(pdu)    ((pdu->ssap & LLC_PDU_RSP) ? 0 : 1)
  47 #define LLC_PDU_IS_RSP(pdu)    ((pdu->ssap & LLC_PDU_RSP) ? 1 : 0)
  48
  49 /* Get PDU type from 2 lowest-order bits of control field first byte */
  50 #define LLC_PDU_TYPE_I_MASK    0x01     /* 16-bit control field */
  51 #define LLC_PDU_TYPE_S_MASK    0x03
  52 #define LLC_PDU_TYPE_U_MASK    0x03     /* 8-bit control field */
  53 #define LLC_PDU_TYPE_MASK      0x03
  54
  55 #define LLC_PDU_TYPE_I          0       /* first bit */
  56 #define LLC_PDU_TYPE_S          1       /* first two bits */
  57 #define LLC_PDU_TYPE_U          3       /* first two bits */
  58 #define LLC_PDU_TYPE_U_XID      4       /* private type for detecting XID commands */
  59
  60 #define LLC_PDU_TYPE_IS_I(pdu) \
  61         ((!(pdu->ctrl_1 & LLC_PDU_TYPE_I_MASK)) ? 1 : 0)
  62
  63 #define LLC_PDU_TYPE_IS_U(pdu) \
  64         (((pdu->ctrl_1 & LLC_PDU_TYPE_U_MASK) == LLC_PDU_TYPE_U) ? 1 : 0)
  65
  66 #define LLC_PDU_TYPE_IS_S(pdu) \
  67         (((pdu->ctrl_1 & LLC_PDU_TYPE_S_MASK) == LLC_PDU_TYPE_S) ? 1 : 0)
  68
  69 /* U-format PDU control field masks */
  70 #define LLC_U_PF_BIT_MASK      0x10     /* P/F bit mask */
  71 #define LLC_U_PF_IS_1(pdu)     ((pdu->ctrl_1 & LLC_U_PF_BIT_MASK) ? 1 : 0)
  72 #define LLC_U_PF_IS_0(pdu)     ((!(pdu->ctrl_1 & LLC_U_PF_BIT_MASK)) ? 1 : 0)
  73
  74 #define LLC_U_PDU_CMD_MASK     0xEC     /* cmd/rsp mask */
  75 #define LLC_U_PDU_CMD(pdu)     (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
  76 #define LLC_U_PDU_RSP(pdu)     (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
  77
  78 #define LLC_1_PDU_CMD_UI       0x00     /* Type 1 cmds/rsps */
  79 #define LLC_1_PDU_CMD_XID      0xAC
  80 #define LLC_1_PDU_CMD_TEST     0xE0
  81
  82 #define LLC_2_PDU_CMD_SABME    0x6C     /* Type 2 cmds/rsps */
  83 #define LLC_2_PDU_CMD_DISC     0x40
  84 #define LLC_2_PDU_RSP_UA       0x60
  85 #define LLC_2_PDU_RSP_DM       0x0C
  86 #define LLC_2_PDU_RSP_FRMR     0x84
  87
  88 /* Type 1 operations */
  89
  90 /* XID information field bit masks */
  91
  92 /* LLC format identifier (byte 1) */
  93 #define LLC_XID_FMT_ID          0x81    /* first byte must be this */
  94
  95 /* LLC types/classes identifier (byte 2) */
  96 #define LLC_XID_CLASS_ZEROS_MASK        0xE0    /* these must be zeros */
  97 #define LLC_XID_CLASS_MASK              0x1F    /* AND with byte to get below */
  98
  99 #define LLC_XID_NULL_CLASS_1    0x01    /* if NULL LSAP...use these */
 100 #define LLC_XID_NULL_CLASS_2    0x03
 101 #define LLC_XID_NULL_CLASS_3    0x05
 102 #define LLC_XID_NULL_CLASS_4    0x07
 103
 104 #define LLC_XID_NNULL_TYPE_1    0x01    /* if non-NULL LSAP...use these */
 105 #define LLC_XID_NNULL_TYPE_2    0x02
 106 #define LLC_XID_NNULL_TYPE_3    0x04
 107 #define LLC_XID_NNULL_TYPE_1_2  0x03
 108 #define LLC_XID_NNULL_TYPE_1_3  0x05
 109 #define LLC_XID_NNULL_TYPE_2_3  0x06
 110 #define LLC_XID_NNULL_ALL               0x07
 111
 112 /* Sender Receive Window (byte 3) */
 113 #define LLC_XID_RW_MASK 0xFE    /* AND with value to get below */
 114
 115 #define LLC_XID_MIN_RW  0x02    /* lowest-order bit always zero */
 116
 117 /* Type 2 operations */
 118
 119 #define LLC_2_SEQ_NBR_MODULO   ((u8) 128)
 120
 121 /* I-PDU masks ('ctrl' is I-PDU control word) */
 122 #define LLC_I_GET_NS(pdu)     (u8)((pdu->ctrl_1 & 0xFE) >> 1)
 123 #define LLC_I_GET_NR(pdu)     (u8)((pdu->ctrl_2 & 0xFE) >> 1)
 124
 125 #define LLC_I_PF_BIT_MASK      0x01
 126
 127 #define LLC_I_PF_IS_0(pdu)     ((!(pdu->ctrl_2 & LLC_I_PF_BIT_MASK)) ? 1 : 0)
 128 #define LLC_I_PF_IS_1(pdu)     ((pdu->ctrl_2 & LLC_I_PF_BIT_MASK) ? 1 : 0)
 129
 130 /* S-PDU supervisory commands and responses */
 131
 132 #define LLC_S_PDU_CMD_MASK     0x0C
 133 #define LLC_S_PDU_CMD(pdu)     (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
 134 #define LLC_S_PDU_RSP(pdu)     (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
 135
 136 #define LLC_2_PDU_CMD_RR       0x00     /* rx ready cmd */
 137 #define LLC_2_PDU_RSP_RR       0x00     /* rx ready rsp */
 138 #define LLC_2_PDU_CMD_REJ      0x08     /* reject PDU cmd */
 139 #define LLC_2_PDU_RSP_REJ      0x08     /* reject PDU rsp */
 140 #define LLC_2_PDU_CMD_RNR      0x04     /* rx not ready cmd */
 141 #define LLC_2_PDU_RSP_RNR      0x04     /* rx not ready rsp */
 142
 143 #define LLC_S_PF_BIT_MASK      0x01
 144 #define LLC_S_PF_IS_0(pdu)     ((!(pdu->ctrl_2 & LLC_S_PF_BIT_MASK)) ? 1 : 0)
 145 #define LLC_S_PF_IS_1(pdu)     ((pdu->ctrl_2 & LLC_S_PF_BIT_MASK) ? 1 : 0)
 146
 147 #define PDU_SUPV_GET_Nr(pdu)   ((pdu->ctrl_2 & 0xFE) >> 1)
 148 #define PDU_GET_NEXT_Vr(sn)    (((sn) + 1) & ~LLC_2_SEQ_NBR_MODULO)
 149
 150 /* FRMR information field macros */
 151
 152 #define FRMR_INFO_LENGTH       5        /* 5 bytes of information */
 153
 154 /*
 155  * info is pointer to FRMR info field structure; 'rej_ctrl' is byte pointer
 156  * (if U-PDU) or word pointer to rejected PDU control field
 157  */
 158 #define FRMR_INFO_SET_REJ_CNTRL(info,rej_ctrl) \
 159         info->rej_pdu_ctrl = ((*((u8 *) rej_ctrl) & \
 160                                 LLC_PDU_TYPE_U) != LLC_PDU_TYPE_U ? \
 161                                 (u16)*((u16 *) rej_ctrl) : \
 162                                 (((u16) *((u8 *) rej_ctrl)) & 0x00FF))
 163
 164 /*
 165  * Info is pointer to FRMR info field structure; 'vs' is a byte containing
 166  * send state variable value in low-order 7 bits (insure the lowest-order
 167  * bit remains zero (0))
 168  */
 169 #define FRMR_INFO_SET_Vs(info,vs) (info->curr_ssv = (((u8) vs) << 1))
 170 #define FRMR_INFO_SET_Vr(info,vr) (info->curr_rsv = (((u8) vr) << 1))
 171
 172 /*
 173  * Info is pointer to FRMR info field structure; 'cr' is a byte containing
 174  * the C/R bit value in the low-order bit
 175  */
 176 #define FRMR_INFO_SET_C_R_BIT(info, cr)  (info->curr_rsv |= (((u8) cr) & 0x01))
 177
 178 /*
 179  * In the remaining five macros, 'info' is pointer to FRMR info field
 180  * structure; 'ind' is a byte containing the bit value to set in the
 181  * lowest-order bit)
 182  */
 183 #define FRMR_INFO_SET_INVALID_PDU_CTRL_IND(info, ind) \
 184        (info->ind_bits = ((info->ind_bits & 0xFE) | (((u8) ind) & 0x01)))
 185
 186 #define FRMR_INFO_SET_INVALID_PDU_INFO_IND(info, ind) \
 187        (info->ind_bits = ( (info->ind_bits & 0xFD) | (((u8) ind) & 0x02)))
 188
 189 #define FRMR_INFO_SET_PDU_INFO_2LONG_IND(info, ind) \
 190        (info->ind_bits = ( (info->ind_bits & 0xFB) | (((u8) ind) & 0x04)))
 191
 192 #define FRMR_INFO_SET_PDU_INVALID_Nr_IND(info, ind) \
 193        (info->ind_bits = ( (info->ind_bits & 0xF7) | (((u8) ind) & 0x08)))
 194
 195 #define FRMR_INFO_SET_PDU_INVALID_Ns_IND(info, ind) \
 196        (info->ind_bits = ( (info->ind_bits & 0xEF) | (((u8) ind) & 0x10)))
 197
 198 /* Sequence-numbered PDU format (4 bytes in length) */
 199 struct llc_pdu_sn {
 200         u8 dsap;
 201         u8 ssap;
 202         u8 ctrl_1;
 203         u8 ctrl_2;
 204 } __packed;
 205
 206 static inline struct llc_pdu_sn *llc_pdu_sn_hdr(struct sk_buff *skb)
 207 {
 208         return (struct llc_pdu_sn *)skb_network_header(skb);
 209 }
 210
 211 /* Un-numbered PDU format (3 bytes in length) */
 212 struct llc_pdu_un {
 213         u8 dsap;
 214         u8 ssap;
 215         u8 ctrl_1;
 216 } __packed;
 217
 218 static inline struct llc_pdu_un *llc_pdu_un_hdr(struct sk_buff *skb)
 219 {
 220         return (struct llc_pdu_un *)skb_network_header(skb);
 221 }
 222
 223 /**
 224  *      llc_pdu_header_init - initializes pdu header
 225  *      @skb: input skb that header must be set into it.
 226  *      @type: type of PDU (U, I or S).
 227  *      @ssap: source sap.
 228  *      @dsap: destination sap.
 229  *      @cr: command/response bit (0 or 1).
 230  *
 231  *      This function sets DSAP, SSAP and command/Response bit in LLC header.
 232  */
 233 static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type,
 234                                        u8 ssap, u8 dsap, u8 cr)
 235 {
 236         int hlen = 4; /* default value for I and S types */
 237         struct llc_pdu_un *pdu;
 238
 239         switch (type) {
 240         case LLC_PDU_TYPE_U:
 241                 hlen = 3;
 242                 break;
 243         case LLC_PDU_TYPE_U_XID:
 244                 hlen = 6;
 245                 break;
 246         }
 247
 248         skb_push(skb, hlen);
 249         skb_reset_network_header(skb);
 250         pdu = llc_pdu_un_hdr(skb);
 251         pdu->dsap = dsap;
 252         pdu->ssap = ssap;
 253         pdu->ssap |= cr;
 254 }
 255
 256 /**
 257  *      llc_pdu_decode_sa - extracts, source address (MAC) of input frame
 258  *      @skb: input skb that source address must be extracted from it.
 259  *      @sa: pointer to source address (6 byte array).
 260  *
 261  *      This function extracts source address(MAC) of input frame.
 262  */
 263 static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa)
 264 {
 265         memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN);
 266 }
 267
 268 /**
 269  *      llc_pdu_decode_da - extracts dest address of input frame
 270  *      @skb: input skb that destination address must be extracted from it
 271  *      @da: pointer to destination address (6 byte array).
 272  *
 273  *      This function extracts destination address(MAC) of input frame.
 274  */
 275 static inline void llc_pdu_decode_da(struct sk_buff *skb, u8 *da)
 276 {
 277         memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN);
 278 }
 279
 280 /**
 281  *      llc_pdu_decode_ssap - extracts source SAP of input frame
 282  *      @skb: input skb that source SAP must be extracted from it.
 283  *      @ssap: source SAP (output argument).
 284  *
 285  *      This function extracts source SAP of input frame. Right bit of SSAP is
 286  *      command/response bit.
 287  */
 288 static inline void llc_pdu_decode_ssap(struct sk_buff *skb, u8 *ssap)
 289 {
 290         *ssap = llc_pdu_un_hdr(skb)->ssap & 0xFE;
 291 }
 292
 293 /**
 294  *      llc_pdu_decode_dsap - extracts dest SAP of input frame
 295  *      @skb: input skb that destination SAP must be extracted from it.
 296  *      @dsap: destination SAP (output argument).
 297  *
 298  *      This function extracts destination SAP of input frame. right bit of
 299  *      DSAP designates individual/group SAP.
 300  */
 301 static inline void llc_pdu_decode_dsap(struct sk_buff *skb, u8 *dsap)
 302 {
 303         *dsap = llc_pdu_un_hdr(skb)->dsap & 0xFE;
 304 }
 305
 306 /**
 307  *      llc_pdu_init_as_ui_cmd - sets LLC header as UI PDU
 308  *      @skb: input skb that header must be set into it.
 309  *
 310  *      This function sets third byte of LLC header as a UI PDU.
 311  */
 312 static inline void llc_pdu_init_as_ui_cmd(struct sk_buff *skb)
 313 {
 314         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 315
 316         pdu->ctrl_1  = LLC_PDU_TYPE_U;
 317         pdu->ctrl_1 |= LLC_1_PDU_CMD_UI;
 318 }
 319
 320 /**
 321  *      llc_pdu_init_as_test_cmd - sets PDU as TEST
 322  *      @skb: Address of the skb to build
 323  *
 324  *      Sets a PDU as TEST
 325  */
 326 static inline void llc_pdu_init_as_test_cmd(struct sk_buff *skb)
 327 {
 328         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 329
 330         pdu->ctrl_1  = LLC_PDU_TYPE_U;
 331         pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
 332         pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
 333 }
 334
 335 /**
 336  *      llc_pdu_init_as_test_rsp - build TEST response PDU
 337  *      @skb: Address of the skb to build
 338  *      @ev_skb: The received TEST command PDU frame
 339  *
 340  *      Builds a pdu frame as a TEST response.
 341  */
 342 static inline void llc_pdu_init_as_test_rsp(struct sk_buff *skb,
 343                                             struct sk_buff *ev_skb)
 344 {
 345         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 346
 347         pdu->ctrl_1  = LLC_PDU_TYPE_U;
 348         pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
 349         pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
 350         if (ev_skb->protocol == htons(ETH_P_802_2)) {
 351                 struct llc_pdu_un *ev_pdu = llc_pdu_un_hdr(ev_skb);
 352                 int dsize;
 353
 354                 dsize = ntohs(eth_hdr(ev_skb)->h_proto) - 3;
 355                 memcpy(((u8 *)pdu) + 3, ((u8 *)ev_pdu) + 3, dsize);
 356                 skb_put(skb, dsize);
 357         }
 358 }
 359
 360 /* LLC Type 1 XID command/response information fields format */
 361 struct llc_xid_info {
 362         u8 fmt_id;      /* always 0x81 for LLC */
 363         u8 type;        /* different if NULL/non-NULL LSAP */
 364         u8 rw;          /* sender receive window */
 365 } __packed;
 366
 367 /**
 368  *      llc_pdu_init_as_xid_cmd - sets bytes 3, 4 & 5 of LLC header as XID
 369  *      @skb: input skb that header must be set into it.
 370  *      @svcs_supported: The class of the LLC (I or II)
 371  *      @rx_window: The size of the receive window of the LLC
 372  *
 373  *      This function sets third,fourth,fifth and sixth bytes of LLC header as
 374  *      a XID PDU.
 375  */
 376 static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
 377                                            u8 svcs_supported, u8 rx_window)
 378 {
 379         struct llc_xid_info *xid_info;
 380         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 381
 382         pdu->ctrl_1      = LLC_PDU_TYPE_U;
 383         pdu->ctrl_1     |= LLC_1_PDU_CMD_XID;
 384         pdu->ctrl_1     |= LLC_U_PF_BIT_MASK;
 385         xid_info         = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
 386         xid_info->fmt_id = LLC_XID_FMT_ID;      /* 0x81 */
 387         xid_info->type   = svcs_supported;
 388         xid_info->rw     = rx_window << 1;      /* size of receive window */
 389
 390         /* no need to push/put since llc_pdu_header_init() has already
 391          * pushed 3 + 3 bytes
 392          */
 393 }
 394
 395 /**
 396  *      llc_pdu_init_as_xid_rsp - builds XID response PDU
 397  *      @skb: Address of the skb to build
 398  *      @svcs_supported: The class of the LLC (I or II)
 399  *      @rx_window: The size of the receive window of the LLC
 400  *
 401  *      Builds a pdu frame as an XID response.
 402  */
 403 static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
 404                                            u8 svcs_supported, u8 rx_window)
 405 {
 406         struct llc_xid_info *xid_info;
 407         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 408
 409         pdu->ctrl_1      = LLC_PDU_TYPE_U;
 410         pdu->ctrl_1     |= LLC_1_PDU_CMD_XID;
 411         pdu->ctrl_1     |= LLC_U_PF_BIT_MASK;
 412
 413         xid_info         = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
 414         xid_info->fmt_id = LLC_XID_FMT_ID;
 415         xid_info->type   = svcs_supported;
 416         xid_info->rw     = rx_window << 1;
 417         skb_put(skb, sizeof(struct llc_xid_info));
 418 }
 419
 420 /* LLC Type 2 FRMR response information field format */
 421 struct llc_frmr_info {
 422         u16 rej_pdu_ctrl;       /* bits 1-8 if U-PDU */
 423         u8  curr_ssv;           /* current send state variable val */
 424         u8  curr_rsv;           /* current receive state variable */
 425         u8  ind_bits;           /* indicator bits set with macro */
 426 } __packed;
 427
 428 void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
 429 void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
 430 void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
 431 void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
 432 void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
 433 void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 434 void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 435 void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 436 void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
 437 void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
 438 void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu,
 439                               u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
 440 void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 441 void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 442 void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 443 void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
 444 #endif /* LLC_PDU_H */