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57 lines
1.3 KiB
57 lines
1.3 KiB
4 weeks ago
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/*
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* modbus_tcp.c
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*
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* Change Logs:
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* Date Author Notes
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* 2024-04-01 qiyongzhong first version
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*/
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4 weeks ago
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#include "modbus_tcp.h"
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#include "modbus_cvt.h"
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4 weeks ago
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#ifdef MB_USING_TCP_PROTOCOL
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int mb_tcp_frm_make(u8 *buf, const mb_tcp_frm_t *frm, mb_pdu_type_t type)//生成tcp帧, 返回帧长度
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{
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int pdu_len = mb_pdu_make(buf + MB_TCP_MBAP_SIZE, &(frm->pdu), type);
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u8 *p = buf;
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p += mb_cvt_u16_put(p, frm->mbap.tid);
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p += mb_cvt_u16_put(p, frm->mbap.pid);
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p += mb_cvt_u16_put(p, pdu_len + 1);
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p += mb_cvt_u8_put(p, frm->mbap.did);
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p += pdu_len;
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return((int)(p - buf));
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}
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int mb_tcp_frm_parse(const u8 *buf, int len, mb_tcp_frm_t *frm, mb_pdu_type_t type)//解析tcp帧, 返回pdu数据长度, 解析失败返回0, 功能码不支持返回-1
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{
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if (len < MB_TCP_FRM_MIN)
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{
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return(0);
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}
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u8 *p = (u8 *)buf;
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p += mb_cvt_u16_get(p, &(frm->mbap.tid));
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p += mb_cvt_u16_get(p, &(frm->mbap.pid));
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p += mb_cvt_u16_get(p, &(frm->mbap.dlen));
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p += mb_cvt_u8_get(p, &(frm->mbap.did));
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int remain = len - (int)(p - buf);
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int pdu_len = mb_pdu_parse(p, remain, &(frm->pdu), type);
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if (pdu_len <= 0)
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{
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return(pdu_len);
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}
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if (remain < pdu_len)
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{
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return(0);
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}
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return(pdu_len);
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}
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#endif
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