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dump1090/net_io.c
Oliver Jowett 278448179d Factor out net services so they're not tied to a static array. 
This lets different things dynamically create the services they need,
and sorts out the horrible hacks that view1090 used to make outgoing
connections. Now you can explicitly create a service and tell it to make
an outgoing connection.

This means that view1090 can now just set all the ports to zero (to disable
the listeners), do a normal net init, then explicitly construct the beast
input service without a listener and tell it to make a connection as needed.
2015-06-26 17:50:51 +01:00

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// Part of dump1090, a Mode S message decoder for RTLSDR devices.
//
// net_io.c: network handling.
//
// Copyright (c) 2014,2015 Oliver Jowett <oliver@mutability.co.uk>
//
// This file is free software: you may copy, redistribute and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation, either version 2 of the License, or (at your
// option) any later version.
//
// This file is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// This file incorporates work covered by the following copyright and
// permission notice:
//
// Copyright (C) 2012 by Salvatore Sanfilippo <antirez@gmail.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "dump1090.h"
/* for PRIX64 */
#include <inttypes.h>
#include <assert.h>
//
// ============================= Networking =============================
//
// Note: here we disregard any kind of good coding practice in favor of
// extreme simplicity, that is:
//
// 1) We only rely on the kernel buffers for our I/O without any kind of
// user space buffering.
// 2) We don't register any kind of event handler, from time to time a
// function gets called and we accept new connections. All the rest is
// handled via non-blocking I/O and manually polling clients to see if
// they have something new to share with us when reading is needed.
static int decodeBinMessage(struct client *c, char *p);
static int decodeHexMessage(struct client *c, char *hex);
static int handleHTTPRequest(struct client *c, char *p);
//
//=========================================================================
//
// Networking "stack" initialization
//
// Init a service with the given read/write characteristics, return the new service.
// Doesn't arrange for the service to listen or connect
struct net_service *serviceInit(const char *descr, struct net_writer *writer, const char *sep, read_handler handler)
{
struct net_service *service;
if (!(service = calloc(sizeof(*service), 1))) {
fprintf(stderr, "Out of memory allocating service %s\n", descr);
exit(1);
}
service->next = Modes.services;
Modes.services = service;
service->descr = descr;
service->listen_fd = -1;
service->connections = 0;
service->writer = writer;
service->read_sep = sep;
service->read_handler = handler;
if (service->writer) {
if (! (service->writer->data = malloc(MODES_OUT_BUF_SIZE)) ) {
fprintf(stderr, "Out of memory allocating output buffer for service %s\n", descr);
exit(1);
}
service->writer->service = service;
service->writer->dataUsed = 0;
service->writer->lastWrite = mstime();
}
return service;
}
// Create a client attached to the given service using the provided socket FD
static struct client *createClient(struct net_service *service, int fd)
{
struct client *c;
anetNonBlock(Modes.aneterr, fd);
if (!(c = (struct client *) malloc(sizeof(*c)))) {
fprintf(stderr, "Out of memory allocating a new %s network client\n", service->descr);
exit(1);
}
c->service = service;
c->next = Modes.clients;
c->fd = fd;
c->buflen = 0;
Modes.clients = c;
anetSetSendBuffer(Modes.aneterr,fd, (MODES_NET_SNDBUF_SIZE << Modes.net_sndbuf_size));
++service->connections;
if (service->writer && service->connections == 1) {
service->writer->lastWrite = mstime(); // suppress heartbeat initially
}
return c;
}
// Initiate an outgoing connection which will use the given service.
// Return the new client or NULL if the connection failed
struct client *serviceConnect(struct net_service *service, char *addr, int port)
{
int s = anetTcpConnect(Modes.aneterr, addr, port);
if (s == ANET_ERR)
return NULL;
return createClient(service, s);
}
// Set up the given service to listen on an address/port.
// _exits_ on failure!
void serviceListen(struct net_service *service, char *bind_addr, int bind_port)
{
int s;
if (service->listen_fd >= 0) {
fprintf(stderr, "Tried to set up the service %s twice!\n", service->descr);
exit(1);
}
s = anetTcpServer(Modes.aneterr, bind_port, bind_addr);
if (s == ANET_ERR) {
fprintf(stderr, "Error opening the listening port %d (%s): %s\n",
bind_port, service->descr, Modes.aneterr);
exit(1);
}
anetNonBlock(Modes.aneterr, s);
service->listen_fd = s;
}
struct net_service *makeBeastInputService(void)
{
return serviceInit("Beast TCP input", NULL, NULL, decodeBinMessage);
}
void modesInitNet(void) {
struct net_service *s;
signal(SIGPIPE, SIG_IGN);
Modes.clients = NULL;
Modes.services = NULL;
// set up listeners
if (Modes.net_output_raw_port) {
s = serviceInit("Raw TCP output", &Modes.raw_out, NULL, NULL);
serviceListen(s, Modes.net_bind_address, Modes.net_output_raw_port);
}
if (Modes.net_output_beast_port) {
s = serviceInit("Beast TCP output", &Modes.beast_out, NULL, NULL);
serviceListen(s, Modes.net_bind_address, Modes.net_output_beast_port);
}
if (Modes.net_output_sbs_port) {
s = serviceInit("Basestation TCP output", &Modes.sbs_out, NULL, NULL);
serviceListen(s, Modes.net_bind_address, Modes.net_output_sbs_port);
}
if (Modes.net_fatsv_port) {
s = serviceInit("FATSV TCP output", &Modes.fatsv_out, NULL, NULL);
serviceListen(s, Modes.net_bind_address, Modes.net_fatsv_port);
}
if (Modes.net_input_raw_port) {
s = serviceInit("Raw TCP input", NULL, "\n", decodeHexMessage);
serviceListen(s, Modes.net_bind_address, Modes.net_input_raw_port);
}
if (Modes.net_input_beast_port) {
s = makeBeastInputService();
serviceListen(s, Modes.net_bind_address, Modes.net_input_beast_port);
}
if (Modes.net_http_port) {
s = serviceInit("HTTP server", NULL, "\r\n\r\n", handleHTTPRequest);
serviceListen(s, Modes.net_bind_address, Modes.net_http_port);
}
}
//
//=========================================================================
//
// This function gets called from time to time when the decoding thread is
// awakened by new data arriving. This usually happens a few times every second
//
static struct client * modesAcceptClients(void) {
int fd, port;
struct net_service *s;
for (s = Modes.services; s; s = s->next) {
if (s->listen_fd >= 0) {
while ((fd = anetTcpAccept(Modes.aneterr, s->listen_fd, NULL, &port)) >= 0) {
createClient(s, fd);
}
}
}
return Modes.clients;
}
//
//=========================================================================
//
// On error free the client, collect the structure, adjust maxfd if needed.
//
static void modesCloseClient(struct client *c) {
if (!c->service) {
fprintf(stderr, "warning: double close of net client\n");
return;
}
// Clean up, but defer removing from the list until modesNetCleanup().
// This is because there may be stackframes still pointing at this
// client (unpredictably: reading from client A may cause client B to
// be freed)
close(c->fd);
c->service->connections--;
// mark it as inactive and ready to be freed
c->fd = -1;
c->service = NULL;
}
//
//=========================================================================
//
// Send the write buffer for the specified writer to all connected clients
//
static void flushWrites(struct net_writer *writer) {
struct client *c;
for (c = Modes.clients; c; c = c->next) {
if (c->service == writer->service) {
#ifndef _WIN32
int nwritten = write(c->fd, writer->data, writer->dataUsed);
#else
int nwritten = send(c->fd, writer->data, writer->dataUsed, 0 );
#endif
if (nwritten != writer->dataUsed) {
modesCloseClient(c);
}
}
}
writer->dataUsed = 0;
writer->lastWrite = mstime();
}
// Prepare to write up to 'len' bytes to the given net_writer.
// Returns a pointer to write to, or NULL to skip this write.
static void *prepareWrite(struct net_writer *writer, int len) {
if (!writer ||
!writer->service ||
!writer->service->connections ||
!writer->data)
return NULL;
if (len > MODES_OUT_BUF_SIZE)
return NULL;
if (writer->dataUsed + len >= MODES_OUT_BUF_SIZE) {
// Flush now to free some space
flushWrites(writer);
}
return writer->data + writer->dataUsed;
}
// Complete a write previously begun by prepareWrite.
// endptr should point one byte past the last byte written
// to the buffer returned from prepareWrite.
static void completeWrite(struct net_writer *writer, void *endptr) {
writer->dataUsed = endptr - writer->data;
if (writer->dataUsed >= Modes.net_output_flush_size) {
flushWrites(writer);
}
}
//
//=========================================================================
//
// Write raw output in Beast Binary format with Timestamp to TCP clients
//
static void modesSendBeastOutput(struct modesMessage *mm) {
int msgLen = mm->msgbits / 8;
char *p = prepareWrite(&Modes.beast_out, 2 + 2 * (7 + msgLen));
char ch;
int j;
unsigned char *msg = (Modes.net_verbatim ? mm->verbatim : mm->msg);
if (!p)
return;
*p++ = 0x1a;
if (msgLen == MODES_SHORT_MSG_BYTES)
{*p++ = '2';}
else if (msgLen == MODES_LONG_MSG_BYTES)
{*p++ = '3';}
else if (msgLen == MODEAC_MSG_BYTES)
{*p++ = '1';}
else
{return;}
/* timestamp, big-endian */
*p++ = (ch = (mm->timestampMsg >> 40));
if (0x1A == ch) {*p++ = ch; }
*p++ = (ch = (mm->timestampMsg >> 32));
if (0x1A == ch) {*p++ = ch; }
*p++ = (ch = (mm->timestampMsg >> 24));
if (0x1A == ch) {*p++ = ch; }
*p++ = (ch = (mm->timestampMsg >> 16));
if (0x1A == ch) {*p++ = ch; }
*p++ = (ch = (mm->timestampMsg >> 8));
if (0x1A == ch) {*p++ = ch; }
*p++ = (ch = (mm->timestampMsg));
if (0x1A == ch) {*p++ = ch; }
*p++ = ch = (char) round(sqrt(mm->signalLevel) * 255);
if (0x1A == ch) {*p++ = ch; }
for (j = 0; j < msgLen; j++) {
*p++ = (ch = msg[j]);
if (0x1A == ch) {*p++ = ch; }
}
completeWrite(&Modes.beast_out, p);
}
//
//=========================================================================
//
// Write raw output to TCP clients
//
static void modesSendRawOutput(struct modesMessage *mm) {
int msgLen = mm->msgbits / 8;
char *p = prepareWrite(&Modes.raw_out, msgLen*2 + 15);
int j;
unsigned char *msg = (Modes.net_verbatim ? mm->verbatim : mm->msg);
if (!p)
return;
if (Modes.mlat && mm->timestampMsg) {
/* timestamp, big-endian */
sprintf(p, "@%012" PRIX64,
mm->timestampMsg);
p += 13;
} else
*p++ = '*';
for (j = 0; j < msgLen; j++) {
sprintf(p, "%02X", msg[j]);
p += 2;
}
*p++ = ';';
*p++ = '\n';
completeWrite(&Modes.raw_out, p);
}
//
//=========================================================================
//
// Write SBS output to TCP clients
// The message structure mm->bFlags tells us what has been updated by this message
//
static void modesSendSBSOutput(struct modesMessage *mm) {
char *p;
struct timespec now;
struct tm stTime_receive, stTime_now;
int msgType;
// For now, suppress non-ICAO addresses
if (mm->addr & MODES_NON_ICAO_ADDRESS)
return;
p = prepareWrite(&Modes.sbs_out, 200);
if (!p)
return;
//
// SBS BS style output checked against the following reference
// http://www.homepages.mcb.net/bones/SBS/Article/Barebones42_Socket_Data.htm - seems comprehensive
//
if (mm->msgtype == -1) {
// heartbeat
p += sprintf(p, "\r\n");
completeWrite(&Modes.sbs_out, p);
return;
}
// Decide on the basic SBS Message Type
if ((mm->msgtype == 4) || (mm->msgtype == 20)) {
msgType = 5;
} else if ((mm->msgtype == 5) || (mm->msgtype == 21)) {
msgType = 6;
} else if ((mm->msgtype == 0) || (mm->msgtype == 16)) {
msgType = 7;
} else if (mm->msgtype == 11) {
msgType = 8;
} else if ((mm->msgtype != 17) && (mm->msgtype != 18)) {
return;
} else if ((mm->metype >= 1) && (mm->metype <= 4)) {
msgType = 1;
} else if ((mm->metype >= 5) && (mm->metype <= 8)) {
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID)
{msgType = 2;}
else
{msgType = 7;}
} else if ((mm->metype >= 9) && (mm->metype <= 18)) {
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID)
{msgType = 3;}
else
{msgType = 7;}
} else if (mm->metype != 19) {
return;
} else if ((mm->mesub == 1) || (mm->mesub == 2)) {
msgType = 4;
} else {
return;
}
// Fields 1 to 6 : SBS message type and ICAO address of the aircraft and some other stuff
p += sprintf(p, "MSG,%d,111,11111,%06X,111111,", msgType, mm->addr);
// Find current system time
clock_gettime(CLOCK_REALTIME, &now);
localtime_r(&now.tv_sec, &stTime_now);
// Find message reception time
localtime_r(&mm->sysTimestampMsg.tv_sec, &stTime_receive);
// Fields 7 & 8 are the message reception time and date
p += sprintf(p, "%04d/%02d/%02d,", (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1), stTime_receive.tm_mday);
p += sprintf(p, "%02d:%02d:%02d.%03u,", stTime_receive.tm_hour, stTime_receive.tm_min, stTime_receive.tm_sec, (unsigned) (mm->sysTimestampMsg.tv_nsec / 1000000U));
// Fields 9 & 10 are the current time and date
p += sprintf(p, "%04d/%02d/%02d,", (stTime_now.tm_year+1900),(stTime_now.tm_mon+1), stTime_now.tm_mday);
p += sprintf(p, "%02d:%02d:%02d.%03u", stTime_now.tm_hour, stTime_now.tm_min, stTime_now.tm_sec, (unsigned) (now.tv_nsec / 1000000U));
// Field 11 is the callsign (if we have it)
if (mm->bFlags & MODES_ACFLAGS_CALLSIGN_VALID) {p += sprintf(p, ",%s", mm->flight);}
else {p += sprintf(p, ",");}
// Field 12 is the altitude (if we have it) - force to zero if we're on the ground
if ((mm->bFlags & MODES_ACFLAGS_AOG_GROUND) == MODES_ACFLAGS_AOG_GROUND) {
p += sprintf(p, ",0");
} else if (mm->bFlags & MODES_ACFLAGS_ALTITUDE_VALID) {
p += sprintf(p, ",%d", mm->altitude);
} else {
p += sprintf(p, ",");
}
// Field 13 is the ground Speed (if we have it)
if (mm->bFlags & MODES_ACFLAGS_SPEED_VALID) {
p += sprintf(p, ",%d", mm->velocity);
} else {
p += sprintf(p, ",");
}
// Field 14 is the ground Heading (if we have it)
if (mm->bFlags & MODES_ACFLAGS_HEADING_VALID) {
p += sprintf(p, ",%d", mm->heading);
} else {
p += sprintf(p, ",");
}
// Fields 15 and 16 are the Lat/Lon (if we have it)
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID) {p += sprintf(p, ",%1.5f,%1.5f", mm->fLat, mm->fLon);}
else {p += sprintf(p, ",,");}
// Field 17 is the VerticalRate (if we have it)
if (mm->bFlags & MODES_ACFLAGS_VERTRATE_VALID) {p += sprintf(p, ",%d", mm->vert_rate);}
else {p += sprintf(p, ",");}
// Field 18 is the Squawk (if we have it)
if (mm->bFlags & MODES_ACFLAGS_SQUAWK_VALID) {p += sprintf(p, ",%x", mm->modeA);}
else {p += sprintf(p, ",");}
// Field 19 is the Squawk Changing Alert flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_FS_VALID) {
if ((mm->fs >= 2) && (mm->fs <= 4)) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
// Field 20 is the Squawk Emergency flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_SQUAWK_VALID) {
if ((mm->modeA == 0x7500) || (mm->modeA == 0x7600) || (mm->modeA == 0x7700)) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
// Field 21 is the Squawk Ident flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_FS_VALID) {
if ((mm->fs >= 4) && (mm->fs <= 5)) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
// Field 22 is the OnTheGround flag (if we have it)
if (mm->bFlags & MODES_ACFLAGS_AOG_VALID) {
if (mm->bFlags & MODES_ACFLAGS_AOG) {
p += sprintf(p, ",-1");
} else {
p += sprintf(p, ",0");
}
} else {
p += sprintf(p, ",");
}
p += sprintf(p, "\r\n");
completeWrite(&Modes.sbs_out, p);
}
//
//=========================================================================
//
void modesQueueOutput(struct modesMessage *mm) {
modesSendSBSOutput(mm);
modesSendBeastOutput(mm);
modesSendRawOutput(mm);
}
//
//=========================================================================
//
// This function decodes a Beast binary format message
//
// The message is passed to the higher level layers, so it feeds
// the selected screen output, the network output and so forth.
//
// If the message looks invalid it is silently discarded.
//
// The function always returns 0 (success) to the caller as there is no
// case where we want broken messages here to close the client connection.
//
static int decodeBinMessage(struct client *c, char *p) {
int msgLen = 0;
int j;
char ch;
unsigned char msg[MODES_LONG_MSG_BYTES];
struct modesMessage mm;
MODES_NOTUSED(c);
memset(&mm, 0, sizeof(mm));
ch = *p++; /// Get the message type
if (0x1A == ch) {p++;}
if ((ch == '1') && (Modes.mode_ac)) { // skip ModeA/C unless user enables --modes-ac
msgLen = MODEAC_MSG_BYTES;
} else if (ch == '2') {
msgLen = MODES_SHORT_MSG_BYTES;
} else if (ch == '3') {
msgLen = MODES_LONG_MSG_BYTES;
}
if (msgLen) {
// Mark messages received over the internet as remote so that we don't try to
// pass them off as being received by this instance when forwarding them
mm.remote = 1;
// Grab the timestamp (big endian format)
mm.timestampMsg = 0;
for (j = 0; j < 6; j++) {
ch = *p++;
mm.timestampMsg = mm.timestampMsg << 8 | (ch & 255);
if (0x1A == ch) {p++;}
}
// record reception time as the time we read it.
clock_gettime(CLOCK_REALTIME, &mm.sysTimestampMsg);
ch = *p++; // Grab the signal level
mm.signalLevel = ((unsigned char)ch / 256.0);
mm.signalLevel = mm.signalLevel * mm.signalLevel + 1e-5;
if (0x1A == ch) {p++;}
for (j = 0; j < msgLen; j++) { // and the data
msg[j] = ch = *p++;
if (0x1A == ch) {p++;}
}
if (msgLen == MODEAC_MSG_BYTES) { // ModeA or ModeC
Modes.stats_current.remote_received_modeac++;
decodeModeAMessage(&mm, ((msg[0] << 8) | msg[1]));
} else {
int result;
Modes.stats_current.remote_received_modes++;
result = decodeModesMessage(&mm, msg);
if (result < 0) {
if (result == -1)
Modes.stats_current.remote_rejected_unknown_icao++;
else
Modes.stats_current.remote_rejected_bad++;
return 0;
} else {
Modes.stats_current.remote_accepted[mm.correctedbits]++;
}
}
useModesMessage(&mm);
}
return (0);
}
//
//=========================================================================
//
// Turn an hex digit into its 4 bit decimal value.
// Returns -1 if the digit is not in the 0-F range.
//
static int hexDigitVal(int c) {
c = tolower(c);
if (c >= '0' && c <= '9') return c-'0';
else if (c >= 'a' && c <= 'f') return c-'a'+10;
else return -1;
}
//
//=========================================================================
//
// This function decodes a string representing message in raw hex format
// like: *8D4B969699155600E87406F5B69F; The string is null-terminated.
//
// The message is passed to the higher level layers, so it feeds
// the selected screen output, the network output and so forth.
//
// If the message looks invalid it is silently discarded.
//
// The function always returns 0 (success) to the caller as there is no
// case where we want broken messages here to close the client connection.
//
static int decodeHexMessage(struct client *c, char *hex) {
int l = strlen(hex), j;
unsigned char msg[MODES_LONG_MSG_BYTES];
struct modesMessage mm;
MODES_NOTUSED(c);
memset(&mm, 0, sizeof(mm));
// Mark messages received over the internet as remote so that we don't try to
// pass them off as being received by this instance when forwarding them
mm.remote = 1;
mm.signalLevel = 1e-5;
// Remove spaces on the left and on the right
while(l && isspace(hex[l-1])) {
hex[l-1] = '\0'; l--;
}
while(isspace(*hex)) {
hex++; l--;
}
// Turn the message into binary.
// Accept *-AVR raw @-AVR/BEAST timeS+raw %-AVR timeS+raw (CRC good) <-BEAST timeS+sigL+raw
// and some AVR records that we can understand
if (hex[l-1] != ';') {return (0);} // not complete - abort
switch(hex[0]) {
case '<': {
mm.signalLevel = ((hexDigitVal(hex[13])<<4) | hexDigitVal(hex[14])) / 256.0;
mm.signalLevel = mm.signalLevel * mm.signalLevel + 1e-5;
hex += 15; l -= 16; // Skip <, timestamp and siglevel, and ;
break;}
case '@': // No CRC check
case '%': { // CRC is OK
hex += 13; l -= 14; // Skip @,%, and timestamp, and ;
break;}
case '*':
case ':': {
hex++; l-=2; // Skip * and ;
break;}
default: {
return (0); // We don't know what this is, so abort
break;}
}
if ( (l != (MODEAC_MSG_BYTES * 2))
&& (l != (MODES_SHORT_MSG_BYTES * 2))
&& (l != (MODES_LONG_MSG_BYTES * 2)) )
{return (0);} // Too short or long message... broken
if ( (0 == Modes.mode_ac)
&& (l == (MODEAC_MSG_BYTES * 2)) )
{return (0);} // Right length for ModeA/C, but not enabled
for (j = 0; j < l; j += 2) {
int high = hexDigitVal(hex[j]);
int low = hexDigitVal(hex[j+1]);
if (high == -1 || low == -1) return 0;
msg[j/2] = (high << 4) | low;
}
// record reception time as the time we read it.
clock_gettime(CLOCK_REALTIME, &mm.sysTimestampMsg);
if (l == (MODEAC_MSG_BYTES * 2)) { // ModeA or ModeC
Modes.stats_current.remote_received_modeac++;
decodeModeAMessage(&mm, ((msg[0] << 8) | msg[1]));
} else { // Assume ModeS
int result;
Modes.stats_current.remote_received_modes++;
result = decodeModesMessage(&mm, msg);
if (result < 0) {
if (result == -1)
Modes.stats_current.remote_rejected_unknown_icao++;
else
Modes.stats_current.remote_rejected_bad++;
return 0;
} else {
Modes.stats_current.remote_accepted[mm.correctedbits]++;
}
}
useModesMessage(&mm);
return (0);
}
//
//=========================================================================
//
// Return a description of planes in json. No metric conversion
//
// usual caveats about function-returning-pointer-to-static-buffer apply
static const char *jsonEscapeString(const char *str) {
static char buf[1024];
const char *in = str;
char *out = buf, *end = buf + sizeof(buf) - 10;
for (; *in && out < end; ++in) {
unsigned char ch = *in;
if (ch == '"' || ch == '\\') {
*out++ = '\\';
*out++ = ch;
} else if (ch < 32 || ch > 127) {
out += snprintf(out, end - out, "\\u%04x", ch);
} else {
*out++ = ch;
}
}
*out++ = 0;
return buf;
}
char *generateAircraftJson(const char *url_path, int *len) {
uint64_t now = mstime();
struct aircraft *a;
int buflen = 1024; // The initial buffer is incremented as needed
char *buf = (char *) malloc(buflen), *p = buf, *end = buf+buflen;
int first = 1;
MODES_NOTUSED(url_path);
p += snprintf(p, end-p,
"{ \"now\" : %.1f,\n"
" \"messages\" : %u,\n"
" \"aircraft\" : [",
now / 1000.0,
Modes.stats_current.messages_total + Modes.stats_alltime.messages_total);
for (a = Modes.aircrafts; a; a = a->next) {
if (a->modeACflags & MODEAC_MSG_FLAG) { // skip any fudged ICAO records Mode A/C
continue;
}
if (a->messages < 2) { // basic filter for bad decodes
continue;
}
if (first)
first = 0;
else
*p++ = ',';
p += snprintf(p, end-p, "\n {\"hex\":\"%s%06x\"", (a->addr & MODES_NON_ICAO_ADDRESS) ? "~" : "", a->addr & 0xFFFFFF);
if (a->bFlags & MODES_ACFLAGS_SQUAWK_VALID)
p += snprintf(p, end-p, ",\"squawk\":\"%04x\"", a->modeA);
if (a->bFlags & MODES_ACFLAGS_CALLSIGN_VALID)
p += snprintf(p, end-p, ",\"flight\":\"%s\"", jsonEscapeString(a->flight));
if (a->bFlags & MODES_ACFLAGS_LATLON_VALID)
p += snprintf(p, end-p, ",\"lat\":%f,\"lon\":%f,\"nucp\":%u,\"seen_pos\":%.1f", a->lat, a->lon, a->pos_nuc, (now - a->seenLatLon)/1000.0);
if ((a->bFlags & MODES_ACFLAGS_AOG_VALID) && (a->bFlags & MODES_ACFLAGS_AOG))
p += snprintf(p, end-p, ",\"altitude\":\"ground\"");
else if (a->bFlags & MODES_ACFLAGS_ALTITUDE_VALID)
p += snprintf(p, end-p, ",\"altitude\":%d", a->altitude);
if (a->bFlags & MODES_ACFLAGS_VERTRATE_VALID)
p += snprintf(p, end-p, ",\"vert_rate\":%d", a->vert_rate);
if (a->bFlags & MODES_ACFLAGS_HEADING_VALID)
p += snprintf(p, end-p, ",\"track\":%d", a->track);
if (a->bFlags & MODES_ACFLAGS_SPEED_VALID)
p += snprintf(p, end-p, ",\"speed\":%d", a->speed);
if (a->bFlags & MODES_ACFLAGS_CATEGORY_VALID)
p += snprintf(p, end-p, ",\"category\":\"%02X\"", a->category);
p += snprintf(p, end-p, ",\"messages\":%ld,\"seen\":%.1f,\"rssi\":%.1f}",
a->messages, (now - a->seen)/1000.0,
10 * log10((a->signalLevel[0] + a->signalLevel[1] + a->signalLevel[2] + a->signalLevel[3] +
a->signalLevel[4] + a->signalLevel[5] + a->signalLevel[6] + a->signalLevel[7] + 1e-5) / 8));
// If we're getting near the end of the buffer, expand it.
if ((end - p) < 256) {
int used = p - buf;
buflen *= 2;
buf = (char *) realloc(buf, buflen);
p = buf+used;
end = buf + buflen;
}
}
p += snprintf(p, end-p, "\n ]\n}\n");
*len = p-buf;
return buf;
}
static char * appendStatsJson(char *p,
char *end,
struct stats *st,
const char *key)
{
int i;
p += snprintf(p, end-p,
"\"%s\":{\"start\":%.1f,\"end\":%.1f",
key,
st->start / 1000.0,
st->end / 1000.0);
if (!Modes.net_only) {
p += snprintf(p, end-p,
",\"local\":{\"samples_processed\":%llu"
",\"samples_dropped\":%llu"
",\"modeac\":%u"
",\"modes\":%u"
",\"bad\":%u"
",\"unknown_icao\":%u",
(unsigned long long)st->samples_processed,
(unsigned long long)st->samples_dropped,
st->demod_modeac,
st->demod_preambles,
st->demod_rejected_bad,
st->demod_rejected_unknown_icao);
for (i=0; i <= Modes.nfix_crc; ++i) {
if (i == 0) p += snprintf(p, end-p, ",\"accepted\":[%u", st->demod_accepted[i]);
else p += snprintf(p, end-p, ",%u", st->demod_accepted[i]);
}
p += snprintf(p, end-p, "]");
if (st->signal_power_sum > 0 && st->signal_power_count > 0)
p += snprintf(p, end-p,",\"signal\":%.1f", 10 * log10(st->signal_power_sum / st->signal_power_count));
if (st->noise_power_sum > 0 && st->noise_power_count > 0)
p += snprintf(p, end-p,",\"noise\":%.1f", 10 * log10(st->noise_power_sum / st->noise_power_count));
if (st->peak_signal_power > 0)
p += snprintf(p, end-p,",\"peak_signal\":%.1f", 10 * log10(st->peak_signal_power));
p += snprintf(p, end-p,",\"strong_signals\":%d}", st->strong_signal_count);
}
if (Modes.net) {
p += snprintf(p, end-p,
",\"remote\":{\"modeac\":%u"
",\"modes\":%u"
",\"bad\":%u"
",\"unknown_icao\":%u",
st->remote_received_modeac,
st->remote_received_modes,
st->remote_rejected_bad,
st->remote_rejected_unknown_icao);
for (i=0; i <= Modes.nfix_crc; ++i) {
if (i == 0) p += snprintf(p, end-p, ",\"accepted\":[%u", st->remote_accepted[i]);
else p += snprintf(p, end-p, ",%u", st->remote_accepted[i]);
}
p += snprintf(p, end-p, "]");
p += snprintf(p, end-p, "},\"http_requests\":%u", st->http_requests);
}
{
uint64_t demod_cpu_millis = (uint64_t)st->demod_cpu.tv_sec*1000UL + st->demod_cpu.tv_nsec/1000000UL;
uint64_t reader_cpu_millis = (uint64_t)st->reader_cpu.tv_sec*1000UL + st->reader_cpu.tv_nsec/1000000UL;
uint64_t background_cpu_millis = (uint64_t)st->background_cpu.tv_sec*1000UL + st->background_cpu.tv_nsec/1000000UL;
p += snprintf(p, end-p,
",\"cpr\":{\"surface\":%u"
",\"airborne\":%u"
",\"global_ok\":%u"
",\"global_bad\":%u"
",\"global_range\":%u"
",\"global_speed\":%u"
",\"global_skipped\":%u"
",\"local_ok\":%u"
",\"local_aircraft_relative\":%u"
",\"local_receiver_relative\":%u"
",\"local_skipped\":%u"
",\"local_range\":%u"
",\"local_speed\":%u"
",\"filtered\":%u}"
",\"cpu\":{\"demod\":%llu,\"reader\":%llu,\"background\":%llu}"
",\"tracks\":{\"all\":%u"
",\"single_message\":%u}"
",\"messages\":%u}",
st->cpr_surface,
st->cpr_airborne,
st->cpr_global_ok,
st->cpr_global_bad,
st->cpr_global_range_checks,
st->cpr_global_speed_checks,
st->cpr_global_skipped,
st->cpr_local_ok,
st->cpr_local_aircraft_relative,
st->cpr_local_receiver_relative,
st->cpr_local_skipped,
st->cpr_local_range_checks,
st->cpr_local_speed_checks,
st->cpr_filtered,
(unsigned long long)demod_cpu_millis,
(unsigned long long)reader_cpu_millis,
(unsigned long long)background_cpu_millis,
st->unique_aircraft,
st->single_message_aircraft,
st->messages_total);
}
return p;
}
char *generateStatsJson(const char *url_path, int *len) {
struct stats add;
char *buf = (char *) malloc(4096), *p = buf, *end = buf + 4096;
MODES_NOTUSED(url_path);
p += snprintf(p, end-p, "{\n");
p = appendStatsJson(p, end, &Modes.stats_current, "latest");
p += snprintf(p, end-p, ",\n");
p = appendStatsJson(p, end, &Modes.stats_1min[Modes.stats_latest_1min], "last1min");
p += snprintf(p, end-p, ",\n");
p = appendStatsJson(p, end, &Modes.stats_5min, "last5min");
p += snprintf(p, end-p, ",\n");
p = appendStatsJson(p, end, &Modes.stats_15min, "last15min");
p += snprintf(p, end-p, ",\n");
add_stats(&Modes.stats_alltime, &Modes.stats_current, &add);
p = appendStatsJson(p, end, &add, "total");
p += snprintf(p, end-p, "\n}\n");
assert(p <= end);
*len = p-buf;
return buf;
}
//
// Return a description of the receiver in json.
//
char *generateReceiverJson(const char *url_path, int *len)
{
char *buf = (char *) malloc(1024), *p = buf;
int history_size;
MODES_NOTUSED(url_path);
// work out number of valid history entries
if (Modes.json_aircraft_history[HISTORY_SIZE-1].content == NULL)
history_size = Modes.json_aircraft_history_next;
else
history_size = HISTORY_SIZE;
p += sprintf(p, "{ " \
"\"version\" : \"%s\", "
"\"refresh\" : %.0f, "
"\"history\" : %d",
MODES_DUMP1090_VERSION, 1.0*Modes.json_interval, history_size);
if (Modes.json_location_accuracy && (Modes.fUserLat != 0.0 || Modes.fUserLon != 0.0)) {
if (Modes.json_location_accuracy == 1) {
p += sprintf(p, ", " \
"\"lat\" : %.2f, "
"\"lon\" : %.2f",
Modes.fUserLat, Modes.fUserLon); // round to 2dp - about 0.5-1km accuracy - for privacy reasons
} else {
p += sprintf(p, ", " \
"\"lat\" : %.6f, "
"\"lon\" : %.6f",
Modes.fUserLat, Modes.fUserLon); // exact location
}
}
p += sprintf(p, " }\n");
*len = (p - buf);
return buf;
}
char *generateHistoryJson(const char *url_path, int *len)
{
int history_index = -1;
if (sscanf(url_path, "/data/history_%d.json", &history_index) != 1)
return NULL;
if (history_index < 0 || history_index >= HISTORY_SIZE)
return NULL;
if (!Modes.json_aircraft_history[history_index].content)
return NULL;
*len = Modes.json_aircraft_history[history_index].clen;
return strdup(Modes.json_aircraft_history[history_index].content);
}
// Write JSON to file
void writeJsonToFile(const char *file, char * (*generator) (const char *,int*))
{
#ifndef _WIN32
char pathbuf[PATH_MAX];
char tmppath[PATH_MAX];
int fd;
int len = 0;
mode_t mask;
char *content;
if (!Modes.json_dir)
return;
snprintf(tmppath, PATH_MAX, "%s/%s.XXXXXX", Modes.json_dir, file);
tmppath[PATH_MAX-1] = 0;
fd = mkstemp(tmppath);
if (fd < 0)
return;
mask = umask(0);
umask(mask);
fchmod(fd, 0644 & ~mask);
snprintf(pathbuf, PATH_MAX, "/data/%s", file);
pathbuf[PATH_MAX-1] = 0;
content = generator(pathbuf, &len);
if (write(fd, content, len) != len)
goto error_1;
if (close(fd) < 0)
goto error_2;
snprintf(pathbuf, PATH_MAX, "%s/%s", Modes.json_dir, file);
pathbuf[PATH_MAX-1] = 0;
rename(tmppath, pathbuf);
free(content);
return;
error_1:
close(fd);
error_2:
unlink(tmppath);
free(content);
return;
#endif
}
//
//=========================================================================
//
#define MODES_CONTENT_TYPE_HTML "text/html;charset=utf-8"
#define MODES_CONTENT_TYPE_CSS "text/css;charset=utf-8"
#define MODES_CONTENT_TYPE_JSON "application/json;charset=utf-8"
#define MODES_CONTENT_TYPE_JS "application/javascript;charset=utf-8"
#define MODES_CONTENT_TYPE_GIF "image/gif"
static struct {
char *path;
char * (*handler)(const char*,int*);
char *content_type;
int prefix;
} url_handlers[] = {
{ "/data/aircraft.json", generateAircraftJson, MODES_CONTENT_TYPE_JSON, 0 },
{ "/data/receiver.json", generateReceiverJson, MODES_CONTENT_TYPE_JSON, 0 },
{ "/data/stats.json", generateStatsJson, MODES_CONTENT_TYPE_JSON, 0 },
{ "/data/history_", generateHistoryJson, MODES_CONTENT_TYPE_JSON, 1 },
{ NULL, NULL, NULL, 0 }
};
//
// Get an HTTP request header and write the response to the client.
// gain here we assume that the socket buffer is enough without doing
// any kind of userspace buffering.
//
// Returns 1 on error to signal the caller the client connection should
// be closed.
//
static int handleHTTPRequest(struct client *c, char *p) {
char hdr[512];
int clen, hdrlen;
int httpver, keepalive;
int statuscode = 500;
const char *statusmsg = "Internal Server Error";
char *url, *content = NULL;
char *ext;
char *content_type;
int i;
if (Modes.debug & MODES_DEBUG_NET)
printf("\nHTTP request: %s\n", c->buf);
// Minimally parse the request.
httpver = (strstr(p, "HTTP/1.1") != NULL) ? 11 : 10;
if (httpver == 10) {
// HTTP 1.0 defaults to close, unless otherwise specified.
//keepalive = strstr(p, "Connection: keep-alive") != NULL;
} else if (httpver == 11) {
// HTTP 1.1 defaults to keep-alive, unless close is specified.
//keepalive = strstr(p, "Connection: close") == NULL;
}
keepalive = 0;
// Identify he URL.
p = strchr(p,' ');
if (!p) return 1; // There should be the method and a space
url = ++p; // Now this should point to the requested URL
p = strchr(p, ' ');
if (!p) return 1; // There should be a space before HTTP/
*p = '\0';
if (Modes.debug & MODES_DEBUG_NET) {
printf("\nHTTP keep alive: %d\n", keepalive);
printf("HTTP requested URL: %s\n\n", url);
}
// Ditch any trailing query part (AJAX might add one to avoid caching)
p = strchr(url, '?');
if (p) *p = 0;
statuscode = 404;
statusmsg = "Not Found";
for (i = 0; url_handlers[i].path; ++i) {
if ((url_handlers[i].prefix && !strncmp(url, url_handlers[i].path, strlen(url_handlers[i].path))) ||
(!url_handlers[i].prefix && !strcmp(url, url_handlers[i].path))) {
content_type = url_handlers[i].content_type;
content = url_handlers[i].handler(url, &clen);
if (!content)
continue;
statuscode = 200;
statusmsg = "OK";
if (Modes.debug & MODES_DEBUG_NET) {
printf("HTTP: 200: %s -> internal (%d bytes, %s)\n", url, clen, content_type);
}
break;
}
}
if (!content) {
struct stat sbuf;
int fd = -1;
char rp[PATH_MAX], hrp[PATH_MAX];
char getFile[1024];
if (strlen(url) < 2) {
snprintf(getFile, sizeof getFile, "%s/gmap.html", HTMLPATH); // Default file
} else {
snprintf(getFile, sizeof getFile, "%s/%s", HTMLPATH, url);
}
if (!realpath(getFile, rp))
rp[0] = 0;
if (!realpath(HTMLPATH, hrp))
strcpy(hrp, HTMLPATH);
clen = -1;
content = strdup("Server error occured");
if (!strncmp(hrp, rp, strlen(hrp))) {
if (stat(getFile, &sbuf) != -1 && (fd = open(getFile, O_RDONLY)) != -1) {
content = (char *) realloc(content, sbuf.st_size);
if (read(fd, content, sbuf.st_size) != -1) {
clen = sbuf.st_size;
statuscode = 200;
statusmsg = "OK";
}
}
} else {
errno = ENOENT;
}
if (clen < 0) {
content = realloc(content, 128);
clen = snprintf(content, 128,"Error opening HTML file: %s", strerror(errno));
statuscode = 404;
statusmsg = "Not Found";
}
if (fd != -1) {
close(fd);
}
// Get file extension and content type
content_type = MODES_CONTENT_TYPE_HTML; // Default content type
ext = strrchr(getFile, '.');
if (ext) {
if (!strcmp(ext, ".json")) {
content_type = MODES_CONTENT_TYPE_JSON;
} else if (!strcmp(ext, ".css")) {
content_type = MODES_CONTENT_TYPE_CSS;
} else if (!strcmp(ext, ".js")) {
content_type = MODES_CONTENT_TYPE_JS;
} else if (!strcmp(ext, ".gif")) {
content_type = MODES_CONTENT_TYPE_GIF;
}
}
if (Modes.debug & MODES_DEBUG_NET) {
printf("HTTP: %d %s: %s -> %s (%d bytes, %s)\n", statuscode, statusmsg, url, rp, clen, content_type);
}
}
// Create the header and send the reply
hdrlen = snprintf(hdr, sizeof(hdr),
"HTTP/1.1 %d %s\r\n"
"Server: Dump1090\r\n"
"Content-Type: %s\r\n"
"Connection: %s\r\n"
"Content-Length: %d\r\n"
"Cache-Control: no-cache, must-revalidate\r\n"
"Expires: Sat, 26 Jul 1997 05:00:00 GMT\r\n"
"\r\n",
statuscode, statusmsg,
content_type,
keepalive ? "keep-alive" : "close",
clen);
if (Modes.debug & MODES_DEBUG_NET) {
printf("HTTP Reply header:\n%s", hdr);
}
// Send header and content.
#ifndef _WIN32
if ( (write(c->fd, hdr, hdrlen) != hdrlen)
|| (write(c->fd, content, clen) != clen) ) {
#else
if ( (send(c->fd, hdr, hdrlen, 0) != hdrlen)
|| (send(c->fd, content, clen, 0) != clen) ) {
#endif
free(content);
return 1;
}
free(content);
Modes.stats_current.http_requests++;
return !keepalive;
}
//
//=========================================================================
//
// This function polls the clients using read() in order to receive new
// messages from the net.
//
// The message is supposed to be separated from the next message by the
// separator 'sep', which is a null-terminated C string.
//
// Every full message received is decoded and passed to the higher layers
// calling the function's 'handler'.
//
// The handler returns 0 on success, or 1 to signal this function we should
// close the connection with the client in case of non-recoverable errors.
//
static void modesReadFromClient(struct client *c) {
int left;
int nread;
int fullmsg;
int bContinue = 1;
char *s, *e, *p;
while(bContinue) {
fullmsg = 0;
left = MODES_CLIENT_BUF_SIZE - c->buflen;
// If our buffer is full discard it, this is some badly formatted shit
if (left <= 0) {
c->buflen = 0;
left = MODES_CLIENT_BUF_SIZE;
// If there is garbage, read more to discard it ASAP
}
#ifndef _WIN32
nread = read(c->fd, c->buf+c->buflen, left);
#else
nread = recv(c->fd, c->buf+c->buflen, left, 0);
if (nread < 0) {errno = WSAGetLastError();}
#endif
// If we didn't get all the data we asked for, then return once we've processed what we did get.
if (nread != left) {
bContinue = 0;
}
if (nread == 0) { // End of file
modesCloseClient(c);
return;
}
#ifndef _WIN32
if (nread < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) { // No data available (not really an error)
#else
if (nread < 0 && errno == EWOULDBLOCK) { // No data available (not really an error)
#endif
return;
}
if (nread < 0) { // Other errors
modesCloseClient(c);
return;
}
c->buflen += nread;
// Always null-term so we are free to use strstr() (it won't affect binary case)
c->buf[c->buflen] = '\0';
e = s = c->buf; // Start with the start of buffer, first message
if (c->service->read_sep == NULL) {
// This is the Beast Binary scanning case.
// If there is a complete message still in the buffer, there must be the separator 'sep'
// in the buffer, note that we full-scan the buffer at every read for simplicity.
left = c->buflen; // Length of valid search for memchr()
while (left > 1 && ((s = memchr(e, (char) 0x1a, left)) != NULL)) { // The first byte of buffer 'should' be 0x1a
s++; // skip the 0x1a
if (*s == '1') {
e = s + MODEAC_MSG_BYTES + 8; // point past remainder of message
} else if (*s == '2') {
e = s + MODES_SHORT_MSG_BYTES + 8;
} else if (*s == '3') {
e = s + MODES_LONG_MSG_BYTES + 8;
} else {
e = s; // Not a valid beast message, skip
left = &(c->buf[c->buflen]) - e;
continue;
}
// we need to be careful of double escape characters in the message body
for (p = s; p < e; p++) {
if (0x1A == *p) {
p++; e++;
if (e > &(c->buf[c->buflen])) {
break;
}
}
}
left = &(c->buf[c->buflen]) - e;
if (left < 0) { // Incomplete message in buffer
e = s - 1; // point back at last found 0x1a.
break;
}
// Have a 0x1a followed by 1, 2 or 3 - pass message less 0x1a to handler.
if (c->service->read_handler(c, s)) {
modesCloseClient(c);
return;
}
fullmsg = 1;
}
s = e; // For the buffer remainder below
} else {
//
// This is the ASCII scanning case, AVR RAW or HTTP at present
// If there is a complete message still in the buffer, there must be the separator 'sep'
// in the buffer, note that we full-scan the buffer at every read for simplicity.
//
while ((e = strstr(s, c->service->read_sep)) != NULL) { // end of first message if found
*e = '\0'; // The handler expects null terminated strings
if (c->service->read_handler(c, s)) { // Pass message to handler.
modesCloseClient(c); // Handler returns 1 on error to signal we .
return; // should close the client connection
}
s = e + strlen(c->service->read_sep); // Move to start of next message
fullmsg = 1;
}
}
if (fullmsg) { // We processed something - so
c->buflen = &(c->buf[c->buflen]) - s; // Update the unprocessed buffer length
memmove(c->buf, s, c->buflen); // Move what's remaining to the start of the buffer
} else { // If no message was decoded process the next client
return;
}
}
}
#define TSV_MAX_PACKET_SIZE 160
static void writeFATSV()
{
struct aircraft *a;
uint64_t now;
static uint64_t next_update;
if (!Modes.fatsv_out.service || !Modes.fatsv_out.service->connections) {
return; // not enabled or no active connections
}
now = mstime();
if (now < next_update) {
return;
}
// scan once a second at most
next_update = now + 1000;
for (a = Modes.aircrafts; a; a = a->next) {
int altValid = 0;
int alt = 0;
uint64_t altAge = 999999;
int groundValid = 0;
int ground = 0;
int latlonValid = 0;
uint64_t latlonAge = 999999;
int speedValid = 0;
uint64_t speedAge = 999999;
int trackValid = 0;
uint64_t trackAge = 999999;
uint64_t emittedAge;
int useful = 0;
int changed = 0;
char *p, *end;
// skip non-ICAO
if (a->addr & MODES_NON_ICAO_ADDRESS)
continue;
if (a->messages < 2) // basic filter for bad decodes
continue;
// don't emit if it hasn't updated since last time
if (a->seen < a->fatsv_last_emitted) {
continue;
}
emittedAge = (now - a->fatsv_last_emitted);
if (a->bFlags & MODES_ACFLAGS_ALTITUDE_VALID) {
alt = a->altitude;
altAge = now - a->seenAltitude;
altValid = (altAge <= 30000);
}
if (a->bFlags & MODES_ACFLAGS_AOG_VALID) {
groundValid = 1;
if (a->bFlags & MODES_ACFLAGS_AOG) {
// force zero altitude on ground
alt = 0;
altValid = 1;
altAge = 0;
ground = 1;
}
}
if (a->bFlags & MODES_ACFLAGS_LATLON_VALID) {
latlonAge = now - a->seenLatLon;
latlonValid = (latlonAge <= 30000);
}
if (a->bFlags & MODES_ACFLAGS_HEADING_VALID) {
trackAge = now - a->seenTrack;
trackValid = (trackAge <= 30000);
}
if (a->bFlags & MODES_ACFLAGS_SPEED_VALID) {
speedAge = now - a->seenSpeed;
speedValid = (speedAge <= 30000);
}
// don't send mode S very often
if (!latlonValid && emittedAge < 30000) {
continue;
}
// if it hasn't changed altitude, heading, or speed much,
// don't update so often
changed = 0;
if (trackValid && abs(a->track - a->fatsv_emitted_track) >= 2) {
changed = 1;
}
if (speedValid && abs(a->speed - a->fatsv_emitted_speed) >= 25) {
changed = 1;
}
if (altValid && abs(alt - a->fatsv_emitted_altitude) >= 50) {
changed = 1;
}
if (!altValid || alt < 10000) {
// Below 10000 feet, emit up to every 5s when changing, 10s otherwise
if (changed && emittedAge < 5000)
continue;
if (!changed && emittedAge < 10000)
continue;
} else {
// Above 10000 feet, emit up to every 10s when changing, 30s otherwise
if (changed && emittedAge < 10000)
continue;
if (!changed && emittedAge < 30000)
continue;
}
p = prepareWrite(&Modes.fatsv_out, TSV_MAX_PACKET_SIZE);
if (!p)
return;
end = p + TSV_MAX_PACKET_SIZE;
# define bufsize(_p,_e) ((_p) >= (_e) ? (size_t)0 : (size_t)((_e) - (_p)))
p += snprintf(p, bufsize(p,end), "clock\t%ld\thexid\t%06X", (long)(a->seen / 1000), a->addr);
if (*a->flight != '\0') {
p += snprintf(p, bufsize(p,end), "\tident\t%s", a->flight);
}
if (a->bFlags & MODES_ACFLAGS_SQUAWK_VALID) {
p += snprintf(p, bufsize(p,end), "\tsquawk\t%04x", a->modeA);
}
// only emit alt, speed, latlon, track if they have been received since the last time
// and are not stale
if (altValid && altAge < emittedAge) {
p += snprintf(p, bufsize(p,end), "\talt\t%d", alt);
useful = 1;
}
if (speedValid && speedAge < emittedAge) {
p += snprintf(p, bufsize(p,end), "\tspeed\t%d", a->speed);
useful = 1;
}
if (groundValid) {
if (ground) {
p += snprintf(p, bufsize(p,end), "\tairGround\tG");
} else {
p += snprintf(p, bufsize(p,end), "\tairGround\tA");
}
}
if (latlonValid && latlonAge < emittedAge) {
p += snprintf(p, bufsize(p,end), "\tlat\t%.5f\tlon\t%.5f", a->lat, a->lon);
useful = 1;
}
if (trackValid && trackAge < emittedAge) {
p += snprintf(p, bufsize(p,end), "\theading\t%d", a->track);
useful = 1;
}
// if we didn't get at least an alt or a speed or a latlon or
// a heading, bail out. We don't need to do anything special
// to unwind prepareWrite().
if (!useful) {
continue;
}
p += snprintf(p, bufsize(p,end), "\n");
if (p <= end)
completeWrite(&Modes.fatsv_out, p);
else
fprintf(stderr, "fatsv: output too large (max %d, overran by %d)\n", TSV_MAX_PACKET_SIZE, (int) (p - end));
# undef bufsize
a->fatsv_last_emitted = now;
a->fatsv_emitted_altitude = alt;
a->fatsv_emitted_track = a->track;
a->fatsv_emitted_speed = a->speed;
}
}
//
// Perform periodic network work
//
void modesNetPeriodicWork(void) {
struct client *c, **prev;
struct net_service *s;
uint64_t now = mstime();
int need_heartbeat = 0, need_flush = 0;
// Accept new connetions
modesAcceptClients();
// Read from clients
for (c = Modes.clients; c; c = c->next) {
if (c->service->read_handler)
modesReadFromClient(c);
}
// Generate FATSV output
writeFATSV();
// If we have generated no messages for a while, generate
// a dummy heartbeat message.
if (Modes.net_heartbeat_interval) {
for (s = Modes.services; s; s = s->next) {
if (s->writer &&
s->connections &&
(s->writer->lastWrite + Modes.net_heartbeat_interval) <= now) {
need_flush = 1;
if (s->writer->dataUsed == 0) {
need_heartbeat = 1;
break;
}
}
}
}
if (need_heartbeat) {
//
// We haven't sent any traffic for some time. To try and keep any TCP
// links alive, send a null frame. This will help stop any routers discarding our TCP
// link which will cause an un-recoverable link error if/when a real frame arrives.
//
// Fudge up a null message
struct modesMessage mm;
memset(&mm, 0, sizeof(mm));
mm.msgbits = MODES_SHORT_MSG_BITS;
mm.timestampMsg = 0;
mm.msgtype = -1;
// Feed output clients
modesQueueOutput(&mm);
}
// If we have data that has been waiting to be written for a while,
// write it now.
for (s = Modes.services; s; s = s->next) {
if (s->writer &&
s->writer->dataUsed &&
(need_flush || (s->writer->lastWrite + Modes.net_output_flush_interval) <= now)) {
flushWrites(s->writer);
}
}
// Unlink and free closed clients
for (prev = &Modes.clients, c = *prev; c; c = *prev) {
if (c->fd == -1) {
// Recently closed, prune from list
*prev = c->next;
free(c);
} else {
prev = &c->next;
}
}
}
//
// =============================== Network IO ===========================
//
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