linux/include/net/llc_pdu.h
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   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) */
 197struct llc_pdu_sn {
 198        u8 dsap;
 199        u8 ssap;
 200        u8 ctrl_1;
 201        u8 ctrl_2;
 202};
 203
 204static 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) */
 210struct llc_pdu_un {
 211        u8 dsap;
 212        u8 ssap;
 213        u8 ctrl_1;
 214};
 215
 216static 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 */
 231static 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 */
 252static 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 */
 269static 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 */
 285static 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 */
 298static 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 */
 309static 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 */
 323static 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 */
 339static 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 */
 358struct 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 */
 371static 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 */
 395static 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 */
 413struct 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
 420extern void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
 421extern void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
 422extern void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
 423extern void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
 424extern void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
 425extern void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 426extern void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 427extern void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 428extern void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
 429extern void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
 430extern 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);
 433extern void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 434extern void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 435extern void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 436extern void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
 437#endif /* LLC_PDU_H */
 438
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