mirror of
https://github.com/servalproject/serval-dna.git
synced 2024-12-23 15:02:27 +00:00
270 lines
8.9 KiB
C
270 lines
8.9 KiB
C
#include "serval.h"
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#include "conf.h"
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int slip_encode(int format,
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unsigned char *src, int src_bytes, unsigned char *dst, int dst_len)
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{
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switch(format) {
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case SLIP_FORMAT_SLIP:
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return WHYF("SLIP encoding not implemented",format);
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break;
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case SLIP_FORMAT_UPPER7:
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/*
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The purpose of this encoder is to work nicely with the RFD900 radios,
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including allowing the reception of RSSI information in the middle of
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packets.
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RSSI reports look like:
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L/R RSSI: 48/0 L/R noise: 62/0 pkts: 0 txe=0 rxe=0 stx=0 srx=0 ecc=0/0 temp=21 dco=0
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So we are using 0x80-0xff to hold data, and { and } to frame packets.
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*/
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if (config.debug.slip) dump("pre-slipped packet",src,src_bytes);
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{
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if (src_bytes<1) return 0;
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if (src_bytes>0x3fff)
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return WHYF("UPPER7 SLIP encoder packets must be <=0x3fff bytes");
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if (dst_len<(9+src_bytes+(src_bytes/7)+1))
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return WHYF("UPPER7 SLIP encoder requires 9+(8/7)*bytes to encode");
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int i,j;
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int out_len=0;
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// Start of packet marker
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dst[out_len++]='{';
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// Length of (unencoded) packet
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dst[out_len++]=0x80+((src_bytes>>7)&0x7f);
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dst[out_len++]=0x80+((src_bytes>>0)&0x7f);
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// Add 32-bit CRC
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// (putting the CRC at the front allows it to be calculated progressively
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// on the receiver side, if we decide to support that)
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unsigned long crc=Crc32_ComputeBuf( 0, src, src_bytes);
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dst[out_len++]=0x80|((crc>>25)&0x7f);
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dst[out_len++]=0x80|((crc>>(25-7))&0x7f);
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dst[out_len++]=0x80|((crc>>(25-7-7))&0x7f);
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dst[out_len++]=0x80|((crc>>(25-7-7-7))&0x7f);
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dst[out_len++]=0x80|((crc>>0)&0x7f);
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for(i=0;i<src_bytes;i+=7)
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{
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// Create 8 bytes of output consisting of 8x7 bits
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// Generate vector of 7 bytes to encode
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unsigned char v[7];
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for(j=0;j<7&&i+j<src_bytes;j++) v[j]=src[i+j];
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for(;j<7;j++) v[j]=0;
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if (out_len+8>dst_len)
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return WHYF("Ran out of space in UPPER7 SLIP encoder (used all %d bytes after encoding %d of %d bytes)",
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dst_len,i,src_bytes);
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// We could use a nice for loop to do this, but for 8 bytes, let's
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// just do it explicitly.
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dst[out_len++]=0x80| (v[0]>>1);
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dst[out_len++]=0x80|((v[0]&0x01)<<6)|(v[1]>>2);
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dst[out_len++]=0x80|((v[1]&0x03)<<5)|(v[2]>>3);
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dst[out_len++]=0x80|((v[2]&0x07)<<4)|(v[3]>>4);
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dst[out_len++]=0x80|((v[3]&0x0f)<<3)|(v[4]>>5);
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dst[out_len++]=0x80|((v[4]&0x1f)<<2)|(v[5]>>6);
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dst[out_len++]=0x80|((v[5]&0x3f)<<1)|(v[6]>>7);
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dst[out_len++]=0x80|((v[6]&0x7f)<<0);
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}
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// Mark end of packet
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dst[out_len++]='}';
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// Detect fatal miscalculations on byte counts
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if (out_len>dst_len) {
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FATALF("overran output buffer in SLIP UPPER7 encapsulation of packet (used %d of %d bytes)",out_len,dst_len);
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}
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return out_len;
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}
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break;
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default:
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return WHYF("Unsupported slip encoding #%d",format);
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}
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}
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unsigned long long last_rssi_report=0;
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int parse_rfd900_rssi(char *s)
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{
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int lrssi,rrssi,lnoise,rnoise,temp;
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// L/R RSSI: 48/0 L/R noise: 62/0 pkts: 0 txe=0 rxe=0 stx=0 srx=0 ecc=0/0 temp=21 dco=0
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if (sscanf(s,"L/R RSSI: %d/%d L/R noise: %d/%d pkts: %*d txe=%*d rxe=%*d stx=%*d srx=%*d ecc=%*d/%*d temp=%d dco=%*d",
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&lrssi,&rrssi,&lnoise,&rnoise,&temp)==5)
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{
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int lmargin=(lrssi-lnoise)/1.9;
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int rmargin=(lrssi-lnoise)/1.9;
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int maxmargin=lmargin; if (rmargin>maxmargin) maxmargin=rmargin;
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if (config.debug.packetradio||(gettime_ms()-last_rssi_report>30000)) {
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INFOF("Link budget = %ddB, temperature=%dC",maxmargin,temp);
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last_rssi_report=gettime_ms();
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}
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}
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return 0;
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}
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#define UPPER7_STATE_NOTINPACKET 0
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#define UPPER7_STATE_L1 1
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#define UPPER7_STATE_L2 2
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#define UPPER7_STATE_C1 3
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#define UPPER7_STATE_C2 4
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#define UPPER7_STATE_C3 5
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#define UPPER7_STATE_C4 6
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#define UPPER7_STATE_C5 7
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#define UPPER7_STATE_D0 8
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#define UPPER7_STATE_D1 9
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#define UPPER7_STATE_D2 10
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#define UPPER7_STATE_D3 11
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#define UPPER7_STATE_D4 12
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#define UPPER7_STATE_D5 13
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#define UPPER7_STATE_D6 14
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#define UPPER7_STATE_D7 15
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int upper7_decode(struct slip_decode_state *state,unsigned char byte)
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{
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if (0&&config.debug.slip)
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DEBUGF("state=%d, byte=0x%02x",state->state,byte);
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// Parse out inline RSSI reports
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if (byte=='{') {
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state->state=UPPER7_STATE_L1;
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state->packet_length=0;
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return 0;
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} else if (byte=='}') {
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// End of packet marker -- report end of received packet to caller
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// for CRC verification etc.
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state->state=UPPER7_STATE_NOTINPACKET; return 1;
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} else if (byte>=' '&&byte<=0x7f) {
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if (state->rssi_len<RSSI_TEXT_SIZE)
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state->rssi_text[state->rssi_len++]=byte;
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return 0;
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} else if (byte=='\r'||byte=='\n') {
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if (state->rssi_len>=RSSI_TEXT_SIZE) state->rssi_len=RSSI_TEXT_SIZE-1;
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if (state->rssi_len<0) state->rssi_len=0;
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state->rssi_text[state->rssi_len]=0;
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parse_rfd900_rssi(state->rssi_text);
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state->rssi_len=0;
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}
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// Non-data bytes (none currently used, but we need to catch them before
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// moving onto processing data bytes)
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if (byte<0x80) {
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switch (byte) {
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default:
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return 0;
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}
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}
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// Data bytes and packet fields
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byte&=0x7f;
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switch(state->state) {
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case UPPER7_STATE_NOTINPACKET: return 0;
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case UPPER7_STATE_L1: state->packet_length=byte<<7; state->state++; return 0;
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case UPPER7_STATE_L2: state->packet_length|=byte;
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// Make sure packet length can fit in RX buffer, including that we might
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// need upto 7 bytes extra temporary space due to blocking
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if ((state->packet_length+7)<OVERLAY_INTERFACE_RX_BUFFER_SIZE) {
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state->state++;
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state->dst_offset=0;
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} else {
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if (config.debug.packetradio)
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DEBUGF("Ignoring jumbo packet of %d bytes",state->packet_length);
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state->state=UPPER7_STATE_NOTINPACKET;
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}
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return 0;
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case UPPER7_STATE_C1: state->crc=byte<<25; state->state++; return 0;
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case UPPER7_STATE_C2: state->crc|=byte<<(25-7); state->state++; return 0;
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case UPPER7_STATE_C3: state->crc|=byte<<(25-7-7); state->state++; return 0;
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case UPPER7_STATE_C4: state->crc|=byte<<(25-7-7-7); state->state++; return 0;
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case UPPER7_STATE_C5: state->crc|=byte<<0; state->state++; return 0;
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case UPPER7_STATE_D0:
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// Prevent buffer overruns
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if (state->dst_offset+7>OVERLAY_INTERFACE_RX_BUFFER_SIZE)
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state=UPPER7_STATE_NOTINPACKET;
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state->dst[state->dst_offset]=byte<<1;
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state->state++;
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return 0;
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case UPPER7_STATE_D1:
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state->dst[state->dst_offset+0]|=(byte>>6)&0x01;
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state->dst[state->dst_offset+1]=(byte<<2);
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state->state++;
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return 0;
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case UPPER7_STATE_D2:
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state->dst[state->dst_offset+1]|=(byte>>5)&0x03;
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state->dst[state->dst_offset+2]=(byte<<3);
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state->state++;
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return 0;
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case UPPER7_STATE_D3:
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state->dst[state->dst_offset+2]|=(byte>>4)&0x07;
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state->dst[state->dst_offset+3]=(byte<<4);
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state->state++;
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return 0;
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case UPPER7_STATE_D4:
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state->dst[state->dst_offset+3]|=(byte>>3)&0x0f;
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state->dst[state->dst_offset+4]=(byte<<5);
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state->state++;
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return 0;
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case UPPER7_STATE_D5:
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state->dst[state->dst_offset+4]|=(byte>>2)&0x1f;
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state->dst[state->dst_offset+5]=(byte<<6);
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state->state++;
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return 0;
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case UPPER7_STATE_D6:
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state->dst[state->dst_offset+5]|=(byte>>1)&0x3f;
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state->dst[state->dst_offset+6]=(byte<<7);
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state->state++;
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return 0;
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case UPPER7_STATE_D7:
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state->dst[state->dst_offset+6]|=(byte>>0)&0x7f;
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state->dst_offset+=7;
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state->state=UPPER7_STATE_D0;
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return 0;
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default:
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state->state=UPPER7_STATE_NOTINPACKET;
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return 0;
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}
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}
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/* state->src and state->src_size contain the freshly read bytes
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we must accumulate any partial state between calls.
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*/
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int slip_decode(struct slip_decode_state *state)
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{
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switch(state->encapsulator) {
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case SLIP_FORMAT_SLIP:
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return WHYF("SLIP encapsulation not implemented");
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case SLIP_FORMAT_UPPER7:
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{
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if (config.debug.slip) {
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if (state->rssi_len<0) state->rssi_len=0;
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if (state->rssi_len>=RSSI_TEXT_SIZE) state->rssi_len=RSSI_TEXT_SIZE-1;
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state->rssi_text[state->rssi_len]=0;
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DEBUGF("RX state=%d, rssi_len=%d, rssi_text='%s'",
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state->state,state->rssi_len,state->rssi_text);
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}
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while(state->src_offset<state->src_size)
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if (upper7_decode(state,state->src[state->src_offset++])==1) {
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if (config.debug.slip)
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dump("de-slipped packet",state->dst,state->packet_length);
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// Check that CRC matches
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uint32_t crc=Crc32_ComputeBuf( 0, state->dst, state->packet_length);
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if (crc!=state->crc) {
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if (config.debug.packetradio||config.debug.rejecteddata)
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DEBUGF("Rejected packet of %d bytes due to CRC mis-match (%08x vs %08x)",
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state->packet_length,crc,state->crc);
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if (config.debug.rejecteddata) {
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dump("bad packet",state->dst,state->packet_length);
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}
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} else {
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if (config.debug.packetradio)
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DEBUGF("Accepted packet of %d bytes (CRC ok)",state->packet_length);
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return 1;
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}
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}
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}
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return 0;
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default:
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return WHYF("Unknown SLIP encapsulation format #%d",state->encapsulator);
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}
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}
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