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-rw-r--r--net/llc/llc_pdu.c372
1 files changed, 372 insertions, 0 deletions
diff --git a/net/llc/llc_pdu.c b/net/llc/llc_pdu.c
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+++ b/net/llc/llc_pdu.c
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+/*
+ * 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, 5);
+}
+
+/**
+ * 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;
+}
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