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