/* * llc_pdu.c - access to PDU internals * * Copyright (c) 1997 by Procom Technology, Inc. * 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br> * * This program can be redistributed or modified under the terms of the * GNU General Public License as published by the Free Software Foundation. * This program is distributed without any warranty or implied warranty * of merchantability or fitness for a particular purpose. * * See the GNU General Public License for more details. */ #include <linux/netdevice.h> #include <net/llc_pdu.h> static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type); static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu); void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 pdu_type) { llc_pdu_un_hdr(skb)->ssap |= pdu_type; } /** * pdu_set_pf_bit - sets poll/final bit in LLC header * @pdu_frame: input frame that p/f bit must be set into it. * @bit_value: poll/final bit (0 or 1). * * This function sets poll/final bit in LLC header (based on type of PDU). * in I or S pdus, p/f bit is right bit of fourth byte in header. in U * pdus p/f bit is fifth bit of third byte. */ void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value) { u8 pdu_type; struct llc_pdu_sn *pdu; llc_pdu_decode_pdu_type(skb, &pdu_type); pdu = llc_pdu_sn_hdr(skb); switch (pdu_type) { case LLC_PDU_TYPE_I: case LLC_PDU_TYPE_S: pdu->ctrl_2 = (pdu->ctrl_2 & 0xFE) | bit_value; break; case LLC_PDU_TYPE_U: pdu->ctrl_1 |= (pdu->ctrl_1 & 0xEF) | (bit_value << 4); break; } } /** * llc_pdu_decode_pf_bit - extracs poll/final bit from LLC header * @skb: input skb that p/f bit must be extracted from it * @pf_bit: poll/final bit (0 or 1) * * This function extracts poll/final bit from LLC header (based on type of * PDU). In I or S pdus, p/f bit is right bit of fourth byte in header. In * U pdus p/f bit is fifth bit of third byte. */ void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit) { u8 pdu_type; struct llc_pdu_sn *pdu; llc_pdu_decode_pdu_type(skb, &pdu_type); pdu = llc_pdu_sn_hdr(skb); switch (pdu_type) { case LLC_PDU_TYPE_I: case LLC_PDU_TYPE_S: *pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK; break; case LLC_PDU_TYPE_U: *pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4; break; } } /** * llc_pdu_init_as_disc_cmd - Builds DISC PDU * @skb: Address of the skb to build * @p_bit: The P bit to set in the PDU * * Builds a pdu frame as a DISC command. */ void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit) { struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_U; pdu->ctrl_1 |= LLC_2_PDU_CMD_DISC; pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK; } /** * llc_pdu_init_as_i_cmd - builds I pdu * @skb: Address of the skb to build * @p_bit: The P bit to set in the PDU * @ns: The sequence number of the data PDU * @nr: The seq. number of the expected I PDU from the remote * * Builds a pdu frame as an I command. */ void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_I; pdu->ctrl_2 = 0; pdu->ctrl_2 |= (p_bit & LLC_I_PF_BIT_MASK); /* p/f bit */ pdu->ctrl_1 |= (ns << 1) & 0xFE; /* set N(S) in bits 2..8 */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_rej_cmd - builds REJ PDU * @skb: Address of the skb to build * @p_bit: The P bit to set in the PDU * @nr: The seq. number of the expected I PDU from the remote * * Builds a pdu frame as a REJ command. */ void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_S; pdu->ctrl_1 |= LLC_2_PDU_CMD_REJ; pdu->ctrl_2 = 0; pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK; pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_rnr_cmd - builds RNR pdu * @skb: Address of the skb to build * @p_bit: The P bit to set in the PDU * @nr: The seq. number of the expected I PDU from the remote * * Builds a pdu frame as an RNR command. */ void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_S; pdu->ctrl_1 |= LLC_2_PDU_CMD_RNR; pdu->ctrl_2 = 0; pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK; pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_rr_cmd - Builds RR pdu * @skb: Address of the skb to build * @p_bit: The P bit to set in the PDU * @nr: The seq. number of the expected I PDU from the remote * * Builds a pdu frame as an RR command. */ void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_S; pdu->ctrl_1 |= LLC_2_PDU_CMD_RR; pdu->ctrl_2 = p_bit & LLC_S_PF_BIT_MASK; pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_sabme_cmd - builds SABME pdu * @skb: Address of the skb to build * @p_bit: The P bit to set in the PDU * * Builds a pdu frame as an SABME command. */ void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit) { struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_U; pdu->ctrl_1 |= LLC_2_PDU_CMD_SABME; pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK; } /** * llc_pdu_init_as_dm_rsp - builds DM response pdu * @skb: Address of the skb to build * @f_bit: The F bit to set in the PDU * * Builds a pdu frame as a DM response. */ void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit) { struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_U; pdu->ctrl_1 |= LLC_2_PDU_RSP_DM; pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK; } /** * llc_pdu_init_as_frmr_rsp - builds FRMR response PDU * @skb: Address of the frame to build * @prev_pdu: The rejected PDU frame * @f_bit: The F bit to set in the PDU * @vs: tx state vari value for the data link conn at the rejecting LLC * @vr: rx state var value for the data link conn at the rejecting LLC * @vzyxw: completely described in the IEEE Std 802.2 document (Pg 55) * * Builds a pdu frame as a FRMR response. */ void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu, u8 f_bit, u8 vs, u8 vr, u8 vzyxw) { struct llc_frmr_info *frmr_info; u8 prev_pf = 0; u8 *ctrl; struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_U; pdu->ctrl_1 |= LLC_2_PDU_RSP_FRMR; pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK; frmr_info = (struct llc_frmr_info *)&pdu->ctrl_2; ctrl = (u8 *)&prev_pdu->ctrl_1; FRMR_INFO_SET_REJ_CNTRL(frmr_info,ctrl); FRMR_INFO_SET_Vs(frmr_info, vs); FRMR_INFO_SET_Vr(frmr_info, vr); prev_pf = llc_pdu_get_pf_bit(prev_pdu); FRMR_INFO_SET_C_R_BIT(frmr_info, prev_pf); FRMR_INFO_SET_INVALID_PDU_CTRL_IND(frmr_info, vzyxw); FRMR_INFO_SET_INVALID_PDU_INFO_IND(frmr_info, vzyxw); FRMR_INFO_SET_PDU_INFO_2LONG_IND(frmr_info, vzyxw); FRMR_INFO_SET_PDU_INVALID_Nr_IND(frmr_info, vzyxw); FRMR_INFO_SET_PDU_INVALID_Ns_IND(frmr_info, vzyxw); skb_put(skb, sizeof(struct llc_frmr_info)); } /** * llc_pdu_init_as_rr_rsp - builds RR response pdu * @skb: Address of the skb to build * @f_bit: The F bit to set in the PDU * @nr: The seq. number of the expected data PDU from the remote * * Builds a pdu frame as an RR response. */ void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_S; pdu->ctrl_1 |= LLC_2_PDU_RSP_RR; pdu->ctrl_2 = 0; pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK; pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_rej_rsp - builds REJ response pdu * @skb: Address of the skb to build * @f_bit: The F bit to set in the PDU * @nr: The seq. number of the expected data PDU from the remote * * Builds a pdu frame as a REJ response. */ void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_S; pdu->ctrl_1 |= LLC_2_PDU_RSP_REJ; pdu->ctrl_2 = 0; pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK; pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_rnr_rsp - builds RNR response pdu * @skb: Address of the frame to build * @f_bit: The F bit to set in the PDU * @nr: The seq. number of the expected data PDU from the remote * * Builds a pdu frame as an RNR response. */ void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_S; pdu->ctrl_1 |= LLC_2_PDU_RSP_RNR; pdu->ctrl_2 = 0; pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK; pdu->ctrl_1 &= 0x0F; /* setting bits 5..8 to zero(reserved) */ pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */ } /** * llc_pdu_init_as_ua_rsp - builds UA response pdu * @skb: Address of the frame to build * @f_bit: The F bit to set in the PDU * * Builds a pdu frame as a UA response. */ void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit) { struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); pdu->ctrl_1 = LLC_PDU_TYPE_U; pdu->ctrl_1 |= LLC_2_PDU_RSP_UA; pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK; } /** * llc_pdu_decode_pdu_type - designates PDU type * @skb: input skb that type of it must be designated. * @type: type of PDU (output argument). * * This function designates type of PDU (I, S or U). */ static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type) { struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); if (pdu->ctrl_1 & 1) { if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U) *type = LLC_PDU_TYPE_U; else *type = LLC_PDU_TYPE_S; } else *type = LLC_PDU_TYPE_I; } /** * llc_pdu_get_pf_bit - extracts p/f bit of input PDU * @pdu: pointer to LLC header. * * This function extracts p/f bit of input PDU. at first examines type of * PDU and then extracts p/f bit. Returns the p/f bit. */ static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu) { u8 pdu_type; u8 pf_bit = 0; if (pdu->ctrl_1 & 1) { if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U) pdu_type = LLC_PDU_TYPE_U; else pdu_type = LLC_PDU_TYPE_S; } else pdu_type = LLC_PDU_TYPE_I; switch (pdu_type) { case LLC_PDU_TYPE_I: case LLC_PDU_TYPE_S: pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK; break; case LLC_PDU_TYPE_U: pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4; break; } return pf_bit; }