static void * blk_thread(void *arg)
{
do {
msgblk_t *blk;
acarsmsg_t msg;
int i,k,pn;
unsigned short crc;
pthread_mutex_lock(&blkmtx);
while(blkq_e==NULL) pthread_cond_wait(&blkwcd,&blkmtx);
blk=blkq_e;
blkq_e=blk->prev;
if(blkq_e==NULL) blkq_s=NULL;
pthread_mutex_unlock(&blkmtx);
if(blk==NULL) return;
if(blk->len<13) {
if(verbose) fprintf(stderr,"#%d too short\n",blk->chn+1);
free(blk);
continue;
}
/* force STX/ETX */
blk->txt[12]&=(ETX|STX);
blk->txt[12]|=(ETX&STX);
msg.err=0;
/* parity check */
pn=0;
for(i=0;i<blk->len;i++) {
if((numbits[blk->txt[i]]&1)==0) {
pn++;
}
}
if(pn>1) {
if(verbose) fprintf(stderr,"#%d too much parity error : %d\n",blk->chn+1,pn);
free(blk);
continue;
}
/* crc check */
crc=0;
for(i=0;i<blk->len;i++) {
update_crc(crc,blk->txt[i]);
}
update_crc(crc,blk->crc[0]);
update_crc(crc,blk->crc[1]);
/* try to fix errors */
if(crc!=0) {
int i,k,fx;
if(verbose) fprintf(stderr,"#%d CRC error, try to recover 1 error\n",blk->chn+1);
fx=0;
for(i=0;i<242*8;i++)
if(oneerr[i]==crc) {
fixerr(blk,i/8,1<<(i%8));
fx=1;
msg.err=1;
break;
}
if(fx==0 && pn==0 && blk->len<142) {
int i,k,l;
unsigned char u,v;
unsigned short n=0;
if(verbose) fprintf(stderr,"#%d CRC error, try to recover 2 close errors\n",blk->chn+1);
for(k=1,v=2;k<8;k++,v<<=1) {
for(l=0,u=1;l<k;l++,u<<=1) {
if(twoerr[n]==crc) {
fixerr(blk,0,u|v);
fx=1;
msg.err=2;
break;
}
n++;
for(i=1;i<142;i++) {
if(twoerr[n]==crc) {
fixerr(blk,i,u|v);
fx=1;
msg.err=2;
break;
}
n++;
}
if(i<142) break;
}
if(l<k) break;
}
}
if(fx==0) {
if(verbose) fprintf(stderr,"#%d not able to fix it\n",blk->chn+1);
free(blk);
continue;
} else {
if(verbose) fprintf(stderr,"#%d fix it\n",blk->chn+1);
}
}
/* redo parity checking and remove parity */
pn=0;
for(i=0;i<blk->len;i++) {
if((numbits[blk->txt[i]]&1)==0) {
pn++;
}
blk->txt[i]&=0x7f;
}
if(pn) {
if(verbose) fprintf(stderr,"#%d parity error %d\n",blk->chn+1,pn);
free(blk);
continue;
}
/* fill msg struct */
msg.txt[0]= '\0';
msg.fid[0] = '\0';
msg.lvl = blk->lvl;
k = 0;
msg.mode = blk->txt[k];
k++;
for (i = 0; i < 7; i++, k++) {
msg.addr[i] = blk->txt[k];
}
msg.addr[7] = '\0';
/* ACK/NAK */
msg.ack = blk->txt[k];
k++;
msg.label[0] = blk->txt[k];
k++;
msg.label[1] = blk->txt[k];
if(msg.label[1]==0x7f) msg.label[1]='d';
k++;
msg.label[2] = '\0';
msg.bid = blk->txt[k];
k++;
/* STX/ETX */
msg.bs=blk->txt[k];
k++;
msg.no[0] = '\0';
msg.fid[0] = '\0';
if(msg.mode <= 0x5d) {
/* donwlink */
if(k<blk->len) {
for (i = 0; i < 4 && k<blk->len-1; i++, k++) {
msg.no[i] = blk->txt[k];
}
msg.no[i] = '\0';
msg.be=blk->txt[blk->len-1];
for (i = 0; i < 6 && k<blk->len-1; i++, k++) {
msg.fid[i] = blk->txt[k];
}
msg.fid[i] = '\0';
}
} else {
/* uplink */
if(airflt) {
free(blk);
continue;
}
}
blk->txt[blk->len-1]='\0';
strncpy(msg.txt, &(blk->txt[k]),240);msg.txt[239]=0;
if(outtype==0)
printoneline(&msg,blk->chn,blk->t);
else if (outtype==1)
printmsg(&msg,blk->chn,blk->t);
else if (outtype==2)
send_udp(&msg,blk->chn,blk->t);
free(blk);
} while(1);
}
void outputmsg(const msgblk_t * blk)
{
acarsmsg_t msg;
int i, k;
/* fill msg struct */
msg.lvl = blk->lvl;
msg.err = blk->err;
k = 0;
msg.mode = blk->txt[k];
k++;
for (i = 0; i < 7; i++, k++) {
msg.addr[i] = blk->txt[k];
}
msg.addr[7] = '\0';
/* ACK/NAK */
msg.ack = blk->txt[k];
if (msg.ack == 0x15)
msg.ack = '!';
k++;
msg.label[0] = blk->txt[k];
k++;
msg.label[1] = blk->txt[k];
if (msg.label[1] == 0x7f)
msg.label[1] = 'd';
k++;
msg.label[2] = '\0';
/*
* downlink: 0 - 9
* uplink: A - Z a - z 0x0(NULL)
*/
msg.bid = blk->txt[k];
if (msg.bid == 0)
msg.bid = ' ';
k++;
/* txt start */
msg.bs = blk->txt[k];
k++;
msg.no[0] = '\0';
msg.fid[0] = '\0';
msg.txt[0] = '\0';
/* Don't display uplink message */
if (((msg.bid >= 'A' && msg.bid <= 'Z') ||
(msg.bid >= 'a' && msg.bid <= 'z') || msg.bid == 0x0) && airflt)
return;
/* STX = 0x03 show that there is no application text */
if (msg.bs != 0x03) {
/* downlink message, has MSN and Flight id */
if (msg.bid >= '0' && msg.bid <= '9') {
/* message no */
for (i = 0; i < 4 && k < blk->len - 1; i++, k++) {
msg.no[i] = blk->txt[k];
}
msg.no[i] = '\0';
/* Flight id */
for (i = 0; i < 6 && k < blk->len - 1; i++, k++) {
msg.fid[i] = blk->txt[k];
}
msg.fid[i] = '\0';
}
/* Message txt */
for (i = 0; k < blk->len - 1; i++, k++)
msg.txt[i] = blk->txt[k];
msg.txt[i] = 0;
}
/* txt end */
msg.be = blk->txt[blk->len - 1];
if (sockfd > 0)
outnet(&msg);
switch (outtype) {
case 0:
break;
case 1:
printoneline(&msg, blk->chn, blk->t);
break;
case 2:
printmsg(&msg, blk->chn, blk->t);
break;
}
}
void outputmsg(const msgblk_t * blk)
{
acarsmsg_t msg;
int i, k;
/* fill msg struct */
msg.lvl = blk->lvl;
msg.err = blk->err;
k = 0;
msg.mode = blk->txt[k];
k++;
for (i = 0; i < 7; i++, k++) {
msg.addr[i] = blk->txt[k];
}
msg.addr[7] = '\0';
/* ACK/NAK */
msg.ack = blk->txt[k];
k++;
msg.label[0] = blk->txt[k];
k++;
msg.label[1] = blk->txt[k];
k++;
msg.label[2] = '\0';
msg.bid = blk->txt[k];
if (msg.bid == 0)
msg.bid = ' ';
k++;
/* txt start */
msg.bs = blk->txt[k];
k++;
msg.no[0] = '\0';
msg.fid[0] = '\0';
msg.txt[0] = '\0';
if ((msg.bs == 0x03 || msg.mode > 'Z' || msg.bid > '9') && airflt)
return;
if (msg.bs != 0x03) {
if (msg.mode <= 'Z' && msg.bid <= '9') {
/* message no */
for (i = 0; i < 4 && k < blk->len - 1; i++, k++) {
msg.no[i] = blk->txt[k];
}
msg.no[i] = '\0';
/* Flight id */
for (i = 0; i < 6 && k < blk->len - 1; i++, k++) {
msg.fid[i] = blk->txt[k];
}
msg.fid[i] = '\0';
}
/* Message txt */
for (i = 0; k < blk->len - 1; i++, k++)
msg.txt[i] = blk->txt[k];
msg.txt[i] = 0;
}
/* txt end */
msg.be = blk->txt[blk->len - 1];
switch (outtype) {
case 1:
twiddle(&msg);
printoneline(&msg, blk->chn, blk->tm);
break;
case 2:
/* printmsg wants it un-twiddled */
printmsg(&msg, blk->chn, blk->tm);
twiddle(&msg);
break;
default:
twiddle(&msg);
break;
}
if (sockfd > 0) {
if (netout == 0)
outpp(&msg);
else
outsv(&msg, blk->chn, blk->tm);
}
}
