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