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 /* 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) + 1) & ~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) */
 196 struct llc_pdu_sn {
 197         u8 dsap;
 198         u8 ssap;
 199         u8 ctrl_1;
 200         u8 ctrl_2;
 201 } __packed;
 202
 203 static 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) */
 209 struct llc_pdu_un {
 210         u8 dsap;
 211         u8 ssap;
 212         u8 ctrl_1;
 213 } __packed;
 214
 215 static 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  */
 230 static 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  */
 251 static 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  */
 264 static 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  */
 278 static 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  */
 291 static 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  */
 302 static 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  */
 316 static 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  */
 332 static 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 */
 351 struct 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  */
 364 static 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  */
 388 static 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 */
 406 struct 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
 413 void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 type);
 414 void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value);
 415 void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit);
 416 void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit);
 417 void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr);
 418 void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 419 void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 420 void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr);
 421 void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit);
 422 void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit);
 423 void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu,
 424                               u8 f_bit, u8 vs, u8 vr, u8 vzyxw);
 425 void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 426 void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 427 void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr);
 428 void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit);
 429 #endif /* LLC_PDU_H */