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P25 -- Tweak MFID A4 MAC GRG Exp Enc;

This commit is contained in:
lwvmobile 2023-09-26 17:39:52 -04:00
parent d52c2b6426
commit ae528f844f
1 changed files with 23 additions and 15 deletions
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38
src/p25p2_vpdu.c
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@ -1412,14 +1412,20 @@ void process_MAC_VPDU(dsd_opts * opts, dsd_state * state, int type, unsigned lon
//MFIDA4 Group Regroup Explicit Encryption Command
if (MAC[1+len_a] == 0xB0 && MAC[2+len_a] == 0xA4) //&& MAC[2+len_a] == 0xA4
{
int len_grg = MAC[3+len_a] & 0x3F;
int grg = MAC[4+len_a] >> 5; //3 bits
int len_grg = MAC[3+len_a] & 0x3F; //MFID Len in Octets
int grg = MAC[4+len_a] >> 5; //3 bits //TIA-102.AABH 4.3.1.1 GRG_Options
int ssn = MAC[4+len_a] & 0x1F; //5 bits
UNUSED(ssn);
fprintf (stderr, "\n MFIDA4 Group Regroup Explicit Encryption Command\n");
//fprintf (stderr, " LEN [%02X] GRG [%02X]\n", len_grg, grg);
if (grg & 0x2) //if grg == wgid //&0x2 according to OP25
{
fprintf (stderr, "\n MFID A4 Group Regroup Explicit Encryption Command\n");
if (len_grg) fprintf (stderr, " Len: %02d", len_grg); //debug
if (grg & 3) fprintf (stderr, " Simulselect"); //one-way regroup
else fprintf (stderr, " Patch"); //two-way regroup
if (grg & 1) fprintf (stderr, " Active"); //activated
else fprintf (stderr, " Inactive"); //deactivated
fprintf (stderr, " SSN: %02d \n", ssn);
if ( (grg & 0x2) == 2) //group WGID to supergroup
{
int sg = (MAC[5+len_a] << 8) | MAC[6+len_a];
int key = (MAC[7+len_a] << 8) | MAC[8+len_a];
int alg = MAC[9+len_a];
@ -1428,10 +1434,13 @@ void process_MAC_VPDU(dsd_opts * opts, dsd_state * state, int type, unsigned lon
int t3 = (MAC[14+len_a] << 8) | MAC[15+len_a];
int t4 = (MAC[16+len_a] << 8) | MAC[17+len_a];
UNUSED4(t1, t2, t3, t4);
fprintf (stderr, " SG [%05d] KEY [%04X] ALG [%02X]\n ", sg, key, alg);
fprintf (stderr, " SG: %d; KEY: %04X; ALG: %02X;\n ", sg, key, alg);
int a = 0;
int wgid = 0;
//worried a bad decode may cause an oob array crash on this one
//sanity check
// if ((len_grg + len_a > 20)) len_grg = 20 - len_a;
for (int i = 10; i < len_grg;)
{
//failsafe to prevent oob array
@ -1440,25 +1449,24 @@ void process_MAC_VPDU(dsd_opts * opts, dsd_state * state, int type, unsigned lon
goto END_PDU;
}
wgid = (MAC[10+len_a+a] << 8) | MAC[11+len_a+a];
fprintf (stderr, "WGID [%05d][%02X] ", wgid, wgid);
fprintf (stderr, "WGID: %d; ", wgid);
a = a + 2;
i = i + 2;
}
}
else //if grg == wuid
else if ( (grg & 0x2) == 0) //individual WUID to supergroup
{
int sg = (MAC[5+len_a] << 8) | MAC[6+len_a];
int key = (MAC[7+len_a] << 8) | MAC[8+len_a];
int t1 = (MAC[9+len_a] << 16) | (MAC[10+len_a] << 8) | MAC[11+len_a];
int t2 = (MAC[12+len_a] << 16) | (MAC[13+len_a] << 8) | MAC[14+len_a];
int t3 = (MAC[15+len_a] << 16) | (MAC[16+len_a] << 8) | MAC[17+len_a];
fprintf (stderr, " SG [%02X] KEY [%04X]", sg, key);
fprintf (stderr, " U1 [%02X] U2 [%02X] U3 [%02X] ", t1, t2, t3);
fprintf (stderr, " SG: %d KEY: %04X", sg, key);
fprintf (stderr, " WUID: %d; WUID: %d; WUID: %d; ", t1, t2, t3);
}
}
//1 or 21, group voice channel message, abb and ext