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 #include <linux/if_tr.h>
  17
  18 /* Lengths of frame formats */
  19 #define LLC_PDU_LEN_I   4       /* header and 2 control bytes */
  20 #define LLC_PDU_LEN_S   4
  21 #define LLC_PDU_LEN_U   3       /* header and 1 control byte */
  22 /* Known SAP addresses */
  23 #define LLC_GLOBAL_SAP  0xFF
  24 #define LLC_NULL_SAP    0x00    /* not network-layer visible */
  25 #define LLC_MGMT_INDIV  0x02    /* station LLC mgmt indiv addr */
  26 #define LLC_MGMT_GRP    0x03    /* station LLC mgmt group addr */
  27 #define LLC_RDE_SAP     0xA6    /* route ... */
  28
  29 /* SAP field bit masks */
  30 #define LLC_ISO_RESERVED_SAP    0x02
  31 #define LLC_SAP_GROUP_DSAP      0x01
  32 #define LLC_SAP_RESP_SSAP       0x01
  33
  34 /* Group/individual DSAP indicator is DSAP field */
  35 #define LLC_PDU_GROUP_DSAP_MASK    0x01
  36 #define LLC_PDU_IS_GROUP_DSAP(pdu)      \
  37         ((pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
  38 #define LLC_PDU_IS_INDIV_DSAP(pdu)      \
  39         (!(pdu->dsap & LLC_PDU_GROUP_DSAP_MASK) ? 0 : 1)
  40
  41 /* Command/response PDU indicator in SSAP field */
  42 #define LLC_PDU_CMD_RSP_MASK    0x01
  43 #define LLC_PDU_CMD             0
  44 #define LLC_PDU_RSP             1
  45 #define LLC_PDU_IS_CMD(pdu)    ((pdu->ssap & LLC_PDU_RSP) ? 0 : 1)
  46 #define LLC_PDU_IS_RSP(pdu)    ((pdu->ssap & LLC_PDU_RSP) ? 1 : 0)
  47
  48 /* Get PDU type from 2 lowest-order bits of control field first byte */
  49 #define LLC_PDU_TYPE_I_MASK    0x01     /* 16-bit control field */
  50 #define LLC_PDU_TYPE_S_MASK    0x03
  51 #define LLC_PDU_TYPE_U_MASK    0x03     /* 8-bit control field */
  52 #define LLC_PDU_TYPE_MASK      0x03
  53
  54 #define LLC_PDU_TYPE_I  0       /* first bit */
  55 #define LLC_PDU_TYPE_S  1       /* first two bits */
  56 #define LLC_PDU_TYPE_U  3       /* first two bits */
  57
  58 #define LLC_PDU_TYPE_IS_I(pdu) \
  59         ((!(pdu->ctrl_1 & LLC_PDU_TYPE_I_MASK)) ? 1 : 0)
  60
  61 #define LLC_PDU_TYPE_IS_U(pdu) \
  62         (((pdu->ctrl_1 & LLC_PDU_TYPE_U_MASK) == LLC_PDU_TYPE_U) ? 1 : 0)
  63
  64 #define LLC_PDU_TYPE_IS_S(pdu) \
  65         (((pdu->ctrl_1 & LLC_PDU_TYPE_S_MASK) == LLC_PDU_TYPE_S) ? 1 : 0)
  66
  67 /* U-format PDU control field masks */
  68 #define LLC_U_PF_BIT_MASK      0x10     /* P/F bit mask */
  69 #define LLC_U_PF_IS_1(pdu)     ((pdu->ctrl_1 & LLC_U_PF_BIT_MASK) ? 1 : 0)
  70 #define LLC_U_PF_IS_0(pdu)     ((!(pdu->ctrl_1 & LLC_U_PF_BIT_MASK)) ? 1 : 0)
  71
  72 #define LLC_U_PDU_CMD_MASK     0xEC     /* cmd/rsp mask */
  73 #define LLC_U_PDU_CMD(pdu)     (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
  74 #define LLC_U_PDU_RSP(pdu)     (pdu->ctrl_1 & LLC_U_PDU_CMD_MASK)
  75
  76 #define LLC_1_PDU_CMD_UI       0x00     /* Type 1 cmds/rsps */
  77 #define LLC_1_PDU_CMD_XID      0xAC
  78 #define LLC_1_PDU_CMD_TEST     0xE0
  79
  80 #define LLC_2_PDU_CMD_SABME    0x6C     /* Type 2 cmds/rsps */
  81 #define LLC_2_PDU_CMD_DISC     0x40
  82 #define LLC_2_PDU_RSP_UA       0x60
  83 #define LLC_2_PDU_RSP_DM       0x0C
  84 #define LLC_2_PDU_RSP_FRMR     0x84
  85
  86 /* Type 1 operations */
  87
  88 /* XID information field bit masks */
  89
  90 /* LLC format identifier (byte 1) */
  91 #define LLC_XID_FMT_ID          0x81    /* first byte must be this */
  92
  93 /* LLC types/classes identifier (byte 2) */
  94 #define LLC_XID_CLASS_ZEROS_MASK        0xE0    /* these must be zeros */
  95 #define LLC_XID_CLASS_MASK              0x1F    /* AND with byte to get below */
  96
  97 #define LLC_XID_NULL_CLASS_1    0x01    /* if NULL LSAP...use these */
  98 #define LLC_XID_NULL_CLASS_2    0x03
  99 #define LLC_XID_NULL_CLASS_3    0x05
 100 #define LLC_XID_NULL_CLASS_4    0x07
 101
 102 #define LLC_XID_NNULL_TYPE_1    0x01    /* if non-NULL LSAP...use these */
 103 #define LLC_XID_NNULL_TYPE_2    0x02
 104 #define LLC_XID_NNULL_TYPE_3    0x04
 105 #define LLC_XID_NNULL_TYPE_1_2  0x03
 106 #define LLC_XID_NNULL_TYPE_1_3  0x05
 107 #define LLC_XID_NNULL_TYPE_2_3  0x06
 108 #define LLC_XID_NNULL_ALL               0x07
 109
 110 /* Sender Receive Window (byte 3) */
 111 #define LLC_XID_RW_MASK 0xFE    /* AND with value to get below */
 112
 113 #define LLC_XID_MIN_RW  0x02    /* lowest-order bit always zero */
 114
 115 /* Type 2 operations */
 116
 117 #define LLC_2_SEQ_NBR_MODULO   ((u8) 128)
 118
 119 /* I-PDU masks ('ctrl' is I-PDU control word) */
 120 #define LLC_I_GET_NS(pdu)     (u8)((pdu->ctrl_1 & 0xFE) >> 1)
 121 #define LLC_I_GET_NR(pdu)     (u8)((pdu->ctrl_2 & 0xFE) >> 1)
 122
 123 #define LLC_I_PF_BIT_MASK      0x01
 124
 125 #define LLC_I_PF_IS_0(pdu)     ((!(pdu->ctrl_2 & LLC_I_PF_BIT_MASK)) ? 1 : 0)
 126 #define LLC_I_PF_IS_1(pdu)     ((pdu->ctrl_2 & LLC_I_PF_BIT_MASK) ? 1 : 0)
 127
 128 /* S-PDU supervisory commands and responses */
 129
 130 #define LLC_S_PDU_CMD_MASK     0x0C
 131 #define LLC_S_PDU_CMD(pdu)     (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
 132 #define LLC_S_PDU_RSP(pdu)     (pdu->ctrl_1 & LLC_S_PDU_CMD_MASK)
 133
 134 #define LLC_2_PDU_CMD_RR       0x00     /* rx ready cmd */
 135 #define LLC_2_PDU_RSP_RR       0x00     /* rx ready rsp */
 136 #define LLC_2_PDU_CMD_REJ      0x08     /* reject PDU cmd */
 137 #define LLC_2_PDU_RSP_REJ      0x08     /* reject PDU rsp */
 138 #define LLC_2_PDU_CMD_RNR      0x04     /* rx not ready cmd */
 139 #define LLC_2_PDU_RSP_RNR      0x04     /* rx not ready rsp */
 140
 141 #define LLC_S_PF_BIT_MASK      0x01
 142 #define LLC_S_PF_IS_0(pdu)     ((!(pdu->ctrl_2 & LLC_S_PF_BIT_MASK)) ? 1 : 0)
 143 #define LLC_S_PF_IS_1(pdu)     ((pdu->ctrl_2 & LLC_S_PF_BIT_MASK) ? 1 : 0)
 144
 145 #define PDU_SUPV_GET_Nr(pdu)   ((pdu->ctrl_2 & 0xFE) >> 1)
 146 #define PDU_GET_NEXT_Vr(sn)    (++sn & ~LLC_2_SEQ_NBR_MODULO)
 147
 148 /* FRMR information field macros */
 149
 150 #define FRMR_INFO_LENGTH       5        /* 5 bytes of information */
 151
 152 /*
 153  * info is pointer to FRMR info field structure; 'rej_ctrl' is byte pointer
 154  * (if U-PDU) or word pointer to rejected PDU control field
 155  */
 156 #define FRMR_INFO_SET_REJ_CNTRL(info,rej_ctrl) \
 157         info->rej_pdu_ctrl = ((*((u8 *) rej_ctrl) & \
 158                                 LLC_PDU_TYPE_U) != LLC_PDU_TYPE_U ? \
 159                                 (u16)*((u16 *) rej_ctrl) : \
 160                                 (((u16) *((u8 *) rej_ctrl)) & 0x00FF))
 161
 162 /*
 163  * Info is pointer to FRMR info field structure; 'vs' is a byte containing
 164  * send state variable value in low-order 7 bits (insure the lowest-order
 165  * bit remains zero (0))
 166  */
 167 #define FRMR_INFO_SET_Vs(info,vs) (info->curr_ssv = (((u8) vs) << 1))
 168 #define FRMR_INFO_SET_Vr(info,vr) (info->curr_rsv = (((u8) vr) << 1))
 169
 170 /*
 171  * Info is pointer to FRMR info field structure; 'cr' is a byte containing
 172  * the C/R bit value in the low-order bit
 173  */
 174 #define FRMR_INFO_SET_C_R_BIT(info, cr)  (info->curr_rsv |= (((u8) cr) & 0x01))
 175
 176 /*
 177  * In the remaining five macros, 'info' is pointer to FRMR info field
 178  * structure; 'ind' is a byte containing the bit value to set in the
 179  * lowest-order bit)
 180  */
 181 #define FRMR_INFO_SET_INVALID_PDU_CTRL_IND(info, ind) \
 182        (info->ind_bits = ((info->ind_bits & 0xFE) | (((u8) ind) & 0x01)))
 183
 184 #define FRMR_INFO_SET_INVALID_PDU_INFO_IND(info, ind) \
 185        (info->ind_bits = ( (info->ind_bits & 0xFD) | (((u8) ind) & 0x02)))
 186
 187 #define FRMR_INFO_SET_PDU_INFO_2LONG_IND(info, ind) \
 188        (info->ind_bits = ( (info->ind_bits & 0xFB) | (((u8) ind) & 0x04)))
 189
 190 #define FRMR_INFO_SET_PDU_INVALID_Nr_IND(info, ind) \
 191        (info->ind_bits = ( (info->ind_bits & 0xF7) | (((u8) ind) & 0x08)))
 192
 193 #define FRMR_INFO_SET_PDU_INVALID_Ns_IND(info, ind) \
 194        (info->ind_bits = ( (info->ind_bits & 0xEF) | (((u8) ind) & 0x10)))
 195
 196 /* Sequence-numbered PDU format (4 bytes in length) */
 197 struct llc_pdu_sn {
 198         u8 dsap;
 199         u8 ssap;
 200         u8 ctrl_1;
 201         u8 ctrl_2;
 202 };
 203
 204 static inline struct llc_pdu_sn *llc_pdu_sn_hdr(struct sk_buff *skb)
 205 {
 206         return (struct llc_pdu_sn *)skb_network_header(skb);
 207 }
 208
 209 /* Un-numbered PDU format (3 bytes in length) */
 210 struct llc_pdu_un {
 211         u8 dsap;
 212         u8 ssap;
 213         u8 ctrl_1;
 214 };
 215
 216 static inline struct llc_pdu_un *llc_pdu_un_hdr(struct sk_buff *skb)
 217 {
 218         return (struct llc_pdu_un *)skb_network_header(skb);
 219 }
 220
 221 /**
 222  *      llc_pdu_header_init - initializes pdu header
 223  *      @skb: input skb that header must be set into it.
 224  *      @type: type of PDU (U, I or S).
 225  *      @ssap: source sap.
 226  *      @dsap: destination sap.
 227  *      @cr: command/response bit (0 or 1).
 228  *
 229  *      This function sets DSAP, SSAP and command/Response bit in LLC header.
 230  */
 231 static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type,
 232                                        u8 ssap, u8 dsap, u8 cr)
 233 {
 234         const int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
 235         struct llc_pdu_un *pdu;
 236
 237         skb_push(skb, hlen);
 238         skb_reset_network_header(skb);
 239         pdu = llc_pdu_un_hdr(skb);
 240         pdu->dsap = dsap;
 241         pdu->ssap = ssap;
 242         pdu->ssap |= cr;
 243 }
 244
 245 /**
 246  *      llc_pdu_decode_sa - extracs source address (MAC) of input frame
 247  *      @skb: input skb that source address must be extracted from it.
 248  *      @sa: pointer to source address (6 byte array).
 249  *
 250  *      This function extracts source address(MAC) of input frame.
 251  */
 252 static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa)
 253 {
 254         if (skb->protocol == htons(ETH_P_802_2))
 255                 memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN);
 256         else if (skb->protocol == htons(ETH_P_TR_802_2)) {
 257                 memcpy(sa, tr_hdr(skb)->saddr, ETH_ALEN);
 258                 *sa &= 0x7F;
 259         }
 260 }
 261
 262 /**
 263  *      llc_pdu_decode_da - extracts dest address of input frame
 264  *      @skb: input skb that destination address must be extracted from it
 265  *      @sa: pointer to destination address (6 byte array).
 266  *
 267  *      This function extracts destination address(MAC) of input frame.
 268  */
 269 static inline void llc_pdu_decode_da(struct sk_buff *skb, u8 *da)
 270 {
 271         if (skb->protocol == htons(ETH_P_802_2))
 272                 memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN);
 273         else if (skb->protocol == htons(ETH_P_TR_802_2))
 274                 memcpy(da, tr_hdr(skb)->daddr, ETH_ALEN);
 275 }
 276
 277 /**
 278  *      llc_pdu_decode_ssap - extracts source SAP of input frame
 279  *      @skb: input skb that source SAP must be extracted from it.
 280  *      @ssap: source SAP (output argument).
 281  *
 282  *      This function extracts source SAP of input frame. Right bit of SSAP is
 283  *      command/response bit.
 284  */
 285 static inline void llc_pdu_decode_ssap(struct sk_buff *skb, u8 *ssap)
 286 {
 287         *ssap = llc_pdu_un_hdr(skb)->ssap & 0xFE;
 288 }
 289
 290 /**
 291  *      llc_pdu_decode_dsap - extracts dest SAP of input frame
 292  *      @skb: input skb that destination SAP must be extracted from it.
 293  *      @dsap: destination SAP (output argument).
 294  *
 295  *      This function extracts destination SAP of input frame. right bit of
 296  *      DSAP designates individual/group SAP.
 297  */
 298 static inline void llc_pdu_decode_dsap(struct sk_buff *skb, u8 *dsap)
 299 {
 300         *dsap = llc_pdu_un_hdr(skb)->dsap & 0xFE;
 301 }
 302
 303 /**
 304  *      llc_pdu_init_as_ui_cmd - sets LLC header as UI PDU
 305  *      @skb: input skb that header must be set into it.
 306  *
 307  *      This function sets third byte of LLC header as a UI PDU.
 308  */
 309 static inline void llc_pdu_init_as_ui_cmd(struct sk_buff *skb)
 310 {
 311         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 312
 313         pdu->ctrl_1  = LLC_PDU_TYPE_U;
 314         pdu->ctrl_1 |= LLC_1_PDU_CMD_UI;
 315 }
 316
 317 /**
 318  *      llc_pdu_init_as_test_cmd - sets PDU as TEST
 319  *      @skb - Address of the skb to build
 320  *
 321  *      Sets a PDU as TEST
 322  */
 323 static inline void llc_pdu_init_as_test_cmd(struct sk_buff *skb)
 324 {
 325         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 326
 327         pdu->ctrl_1  = LLC_PDU_TYPE_U;
 328         pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
 329         pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
 330 }
 331
 332 /**
 333  *      llc_pdu_init_as_test_rsp - build TEST response PDU
 334  *      @skb: Address of the skb to build
 335  *      @ev_skb: The received TEST command PDU frame
 336  *
 337  *      Builds a pdu frame as a TEST response.
 338  */
 339 static inline void llc_pdu_init_as_test_rsp(struct sk_buff *skb,
 340                                             struct sk_buff *ev_skb)
 341 {
 342         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 343
 344         pdu->ctrl_1  = LLC_PDU_TYPE_U;
 345         pdu->ctrl_1 |= LLC_1_PDU_CMD_TEST;
 346         pdu->ctrl_1 |= LLC_U_PF_BIT_MASK;
 347         if (ev_skb->protocol == htons(ETH_P_802_2)) {
 348                 struct llc_pdu_un *ev_pdu = llc_pdu_un_hdr(ev_skb);
 349                 int dsize;
 350
 351                 dsize = ntohs(eth_hdr(ev_skb)->h_proto) - 3;
 352                 memcpy(((u8 *)pdu) + 3, ((u8 *)ev_pdu) + 3, dsize);
 353                 skb_put(skb, dsize);
 354         }
 355 }
 356
 357 /* LLC Type 1 XID command/response information fields format */
 358 struct llc_xid_info {
 359         u8 fmt_id;      /* always 0x81 for LLC */
 360         u8 type;        /* different if NULL/non-NULL LSAP */
 361         u8 rw;          /* sender receive window */
 362 };
 363
 364 /**
 365  *      llc_pdu_init_as_xid_cmd - sets bytes 3, 4 & 5 of LLC header as XID
 366  *      @skb: input skb that header must be set into it.
 367  *
 368  *      This function sets third,fourth,fifth and sixth bytes of LLC header as
 369  *      a XID PDU.
 370  */
 371 static inline void llc_pdu_init_as_xid_cmd(struct sk_buff *skb,
 372                                            u8 svcs_supported, u8 rx_window)
 373 {
 374         struct llc_xid_info *xid_info;
 375         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 376
 377         pdu->ctrl_1      = LLC_PDU_TYPE_U;
 378         pdu->ctrl_1     |= LLC_1_PDU_CMD_XID;
 379         pdu->ctrl_1     |= LLC_U_PF_BIT_MASK;
 380         xid_info         = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
 381         xid_info->fmt_id = LLC_XID_FMT_ID;      /* 0x81 */
 382         xid_info->type   = svcs_supported;
 383         xid_info->rw     = rx_window << 1;      /* size of receive window */
 384         skb_put(skb, sizeof(struct llc_xid_info));
 385 }
 386
 387 /**
 388  *      llc_pdu_init_as_xid_rsp - builds XID response PDU
 389  *      @skb: Address of the skb to build
 390  *      @svcs_supported: The class of the LLC (I or II)
 391  *      @rx_window: The size of the receive window of the LLC
 392  *
 393  *      Builds a pdu frame as an XID response.
 394  */
 395 static inline void llc_pdu_init_as_xid_rsp(struct sk_buff *skb,
 396                                            u8 svcs_supported, u8 rx_window)
 397 {
 398         struct llc_xid_info *xid_info;
 399         struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
 400
 401         pdu->ctrl_1      = LLC_PDU_TYPE_U;
 402         pdu->ctrl_1     |= LLC_1_PDU_CMD_XID;
 403         pdu->ctrl_1     |= LLC_U_PF_BIT_MASK;
 404
 405         xid_info         = (struct llc_xid_info *)(((u8 *)&pdu->ctrl_1) + 1);
 406         xid_info->fmt_id = LLC_XID_FMT_ID;
 407         xid_info->type   = svcs_supported;
 408         xid_info->rw     = rx_window << 1;
 409         skb_put(skb, sizeof(struct llc_xid_info));
 410 }
 411
 412 /* LLC Type 2 FRMR response information field format */
 413 struct llc_frmr_info {
 414         u16 rej_pdu_ctrl;       /* bits 1-8 if U-PDU */
 415         u8  curr_ssv;           /* current send state variable val */
 416         u8  curr_rsv;           /* current receive state variable */
 417         u8  ind_bits;           /* indicator bits set with macro */
 418 };
 419
 420 extern void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
 421 extern void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
 422 extern void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
 423 extern void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
 424 extern void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
 425 extern void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 426 extern void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 427 extern void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 428 extern void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
 429 extern void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
 430 extern void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb,
 431                                      struct llc_pdu_sn *prev_pdu,
 432                                      u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
 433 extern void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 434 extern void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 435 extern void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 436 extern void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
 437 #endif /* LLC_PDU_H */