minor cleanups - buffer sizes, use asprintf when possible

README.md

@@ -5,10 +5,17 @@ several respects:
 1. Efficient multichannel reception. A single Raspberry Pi 4 can
 simultaneously demodulate, in real time, every NBFM channel on a
 VHF/UHF band (i.e., several hundred) with plenty of real time left
-over. A mid-range x86 can handle the RX888 MkII at full sample rate
+over.
+
+A mid-range x86 can handle the RX888 MkII at full sample rate
 (129.6 MHz), receiving multiple channels sumultaneously on all
 LF/MF/HF ham bands (or anything else) plus 6 meters.
 
+A Raspberry Pi 5 can handle the RX888 MkII at half sample rate (64.8
+MHz), enough to receive up to 30 MHz. (An external hardware anti-alias
+filter is required, and "FFTW Wisdom" must be generated for the Pi5 to
+run this fast.)
+
 2. All I/O (both signal and control/status) uses IP multicasting.
 This makes it easy for more than one module, on the same computer or
 on a LAN, to operate on the outputs of other modules, or for
@@ -34,7 +41,7 @@ downconverters and simple demodulators for various linear and FM
 modes, including AM, SSB, CW and a raw IQ mode intended mainly for use
 by other programs.
 
-Previous versions of ka9q-radio had separate programs (e.g.,
+Previous versions (before mid-2023) of ka9q-radio had separate programs (e.g.,
 *airspyd*) for talking to several makes of SDR front end hardware and
 generated an I/Q multicast stream for *radiod*. Because of performance
 problems, code and configuration complexity and general lack of
@@ -60,6 +67,11 @@ by much more sophisticated user interfaces. Various utilities are
 provided to record or play back signal streams, compress PCM audio
 into Opus, pipe a stream into digital demodulators, etc.
 
+*Radiod* now periodically multicasts ("beacons") status information on
+each output stream and user programs are being enhanced to make
+use of it. For example, *monitor* now displays the frequency, mode and
+signal-to-noise ratio of each channe.
+
 Although I've been running all this myself for several years, it is
 NOT yet ready for general use. A LOT of work still remains, especially
 documentation. But you're welcome to look at it, make comments and
@@ -82,7 +94,7 @@ requirement is that the impulse response of the channel
 filters be shorter than the (configurable) overlap interval in the forward
 FFT.
 
-Updated 10 September 2023  
+Updated 11 April 2024  
 Phil Karn, KA9Q  
 karn@ka9q.net
 

aprsfeed.c

@@ -223,7 +223,7 @@ int main(int argc,char *argv[]){
       }
 
       // Construct TNC2-style monitor string for APRS reporting
-      char monstring[2048]; // Should be large enough for any legal AX.25 frame; we'll assert this periodically
+      char monstring[PKTSIZE]; // Should be large enough for any legal AX.25 frame; we'll assert this periodically
       int sspace = sizeof(monstring);
       int infolen = 0;
       int is_tcpip = 0;

audio.c

@@ -1,6 +1,6 @@
 // Audio multicast routines for ka9q-radio
 // Handles linear 16-bit PCM, mono and stereo
-// Copyright 2017-2023 Phil Karn, KA9Q
+// Copyright 2017-2024 Phil Karn, KA9Q
 
 #define _GNU_SOURCE 1
 #include <assert.h>
@@ -90,14 +90,16 @@ int send_output(struct channel * restrict const chan,float const * restrict buff
     int r = sendto(Output_fd,&packet,dp - packet,0,(struct sockaddr *)&chan->output.dest_socket,sizeof(chan->output.dest_socket));
     chan->output.samples += chunk * chan->output.channels; // Count frames
     if(r <= 0){
-      if(errno == EAGAIN && !TempSendFailure){
-	fprintf(stdout,"Temporary send failure, suggest increased buffering (see sysctl net.core.wmem_max, net.core.wmem_default\n");
-	fprintf(stdout,"Additional messages suppressed\n");
-	TempSendFailure = true;
-	return 0; // Treat as soft failure
+      if(errno == EAGAIN){
+	if(!TempSendFailure){
+	  fprintf(stdout,"Temporary send failure, suggest increased buffering (see sysctl net.core.wmem_max, net.core.wmem_default\n");
+	  fprintf(stdout,"Additional messages suppressed\n");
+	  TempSendFailure = true;
+	}
+      } else {
+	fprintf(stdout,"audio send failure: %s\n",strerror(errno));
+	abort(); // Probably more serious, like the loss of an interface or route
       }
-      fprintf(stdout,"audio send failure: %s\n",strerror(errno));
-      abort(); // Probably more serious, like the loss of an interface or route
     }
     frames -= chunk;
     if(chan->output.pacing && frames > 0)

avahi.c

@@ -7,25 +7,37 @@
 #include "avahi.h"
 
 int avahi_start(char const *service_name,char const *service_type,int const service_port,char const *dns_name,int address,char const *description,void *sock,int *socksize){
-  int pid = getpid();
+  if(sock != NULL && socksize != NULL){
+    // Return sockaddr structure
+    if(*socksize >= sizeof(struct sockaddr_in)){
+      struct sockaddr_in *sin = sock;
+      sin->sin_family = AF_INET;
+      sin->sin_addr.s_addr = htonl(address);
+      sin->sin_port = htons(service_port);
+      *socksize = sizeof(struct sockaddr_in);
+    } else
+      *socksize = 0;
+  }
+  int pid = getpid(); // Advertise the parent's pid, not the child's
   if(fork() == 0){
 #if 0
     fprintf(stdout,"avahi-publish-service child pid %d\n",getpid());
 #endif
-    // run avahi-publish-service --no-fail --host=dns_name service_name service_type service_port description pid hostname in subprocess
-    char port_string[1024];
-    snprintf(port_string, sizeof(port_string), "%d", service_port);
+    // run "avahi-publish-service --no-fail --host=dns_name service_name service_type service_port description pid hostname" in subprocess
+    // No need to free the asprintf-allocated strings, we're calling exec anyway
+    char *port_string;
+    asprintf(&port_string, "%d", service_port);
 
-    char host_string[1024];
-    snprintf(host_string, sizeof(host_string), "--host=%s",dns_name);
+    char *host_string;
+    asprintf(&host_string, "--host=%s",dns_name);
 
-    char pid_string[1024];
-    snprintf(pid_string, sizeof(pid_string), "pid=%d", pid);
+    char *pid_string;
+    asprintf(&pid_string, "pid=%d", pid);
 
     char hostname[sysconf(_SC_HOST_NAME_MAX)];
     gethostname(hostname,sizeof(hostname));
-    char source_string[1024];
-    snprintf(source_string, sizeof(source_string), "source=%s", hostname);
+    char *source_string;
+    asprintf(&source_string, "source=%s", hostname);
 
 #if 0
     fprintf(stdout,"%s %s %s %s %s %s %s %s %s %s\n",
@@ -35,25 +47,12 @@ int avahi_start(char const *service_name,char const *service_type,int const serv
     perror("exec avahi publish service");
     return -1;
   }
-  char ip_address_string[1024];
-  snprintf(ip_address_string,sizeof(ip_address_string),"%d.%d.%d.%d",(address >> 24) & 0xff, (address >> 16) & 0xff, (address >> 8) & 0xff, address & 0xff);
+  if(fork() == 0){
+    char *ip_address_string;    // No need to free, we're calling exec
+    asprintf(&ip_address_string,"%d.%d.%d.%d",(address >> 24) & 0xff, (address >> 16) & 0xff, (address >> 8) & 0xff, address & 0xff);
 #if 0
-  fprintf(stdout,"avahi start: ip address string = %s\n",ip_address_string);
+    fprintf(stdout,"avahi start: ip address string = %s\n",ip_address_string);
 #endif
-
-  if(sock != NULL && socksize != NULL){
-    // Return sockaddr structure
-    if(*socksize >= sizeof(struct sockaddr_in)){
-      struct sockaddr_in *sin = sock;
-      sin->sin_family = AF_INET;
-      sin->sin_addr.s_addr = htonl(address);
-      sin->sin_port = htons(service_port);
-      *socksize = sizeof(struct sockaddr_in);
-    } else
-      *socksize = 0;
-  }
-
-  if(fork() == 0){
     fprintf(stdout,"avahi-publish-address child pid %d\n",getpid());
     // run "avahi-publish-address dns_name address"
 #if 0

main.c

@@ -377,7 +377,7 @@ static int loadconfig(char const * const file){
   // Set up status/command stream, global for all receiver channels
   {
     // Form default status dns name
-    char hostname[1024];
+    char hostname[sysconf(_SC_HOST_NAME_MAX)];
     gethostname(hostname,sizeof(hostname));
     // Edit off .domain, .local, etc
     char *cp = strchr(hostname,'.');

opusd.c

@@ -246,12 +246,12 @@ int main(int argc,char * const argv[]){
     Status_fd = listen_mcast(&Metadata_in_socket,iface);
   }
 
-  char description[1024];
-  snprintf(description,sizeof(description),"pcm-source=%s",Input); // what if it changes?
-  int socksize = sizeof(Opus_out_socket);
-  uint32_t addr = (239U << 24) | (ElfHashString(Output) & 0xffffff);
-  avahi_start(Name,"_opus._udp",DEFAULT_RTP_PORT,Output,addr,description,&Opus_out_socket,&socksize);
   {
+    char description[1024];
+    snprintf(description,sizeof(description),"pcm-source=%s",Input); // what if it changes?
+    int socksize = sizeof(Opus_out_socket);
+    uint32_t addr = (239U << 24) | (ElfHashString(Output) & 0xffffff);
+    avahi_start(Name,"_opus._udp",DEFAULT_RTP_PORT,Output,addr,description,&Opus_out_socket,&socksize);
     struct sockaddr_in *sin = (struct sockaddr_in *)&Metadata_out_socket;
     sin->sin_family = AF_INET;
     sin->sin_addr.s_addr = htonl(addr);

pcmrecord.c

@@ -1,5 +1,5 @@
 // Read and record PCM audio streams
-// Copyright 2021 Phil Karn, KA9Q
+// Copyright 2021-2024 Phil Karn, KA9Q
 #define _GNU_SOURCE 1
 #include <assert.h>
 #include <errno.h>

pcmspawn.c

@@ -48,7 +48,7 @@ struct session {
 
 
 // Command line params
-const char *App_path;
+char const *App_path;
 int Verbose;                  // Verbosity flag (currently unused)
 
 // Global variables
@@ -61,9 +61,9 @@ int Status_out_fd = -1;       // Writing to radio status
 int Input_fd = -1;            // Multicast receive socket
 struct session *Sessions;
 pthread_mutex_t Session_protect = PTHREAD_MUTEX_INITIALIZER;
-char *Command;
-char *Input;
-char *Status;
+char const *Command;
+char const *Input;
+char const *Status;
 
 void closedown(int);
 struct session *lookup_session(const struct sockaddr *,uint32_t,int);
@@ -223,7 +223,7 @@ int main(int argc,char * const argv[]){
       // sample rate
       // sending IP address & port
 
-      char command_line[2048];
+      char command_line[4096]; // I think that's the longest shell command
       int const samprate = samprate_from_pt(sp->type);
       int const channels = channels_from_pt(sp->type);
 
@@ -294,7 +294,7 @@ void * status(void *p){
 
   while(true){
     socklen_t socklen = sizeof(Status_input_source_address);
-    uint8_t buffer[16384];
+    uint8_t buffer[PKTSIZE];
     int const length = recvfrom(Status_fd,buffer,sizeof(buffer),0,(struct sockaddr *)&Status_input_source_address,&socklen);
     if(length <= 0){
       if(errno == EAGAIN || errno == ETIMEDOUT)
@@ -459,7 +459,7 @@ void closedown(int s){
 }
 // Send empty poll command on specified descriptor
 static int send_poll(int fd,int ssrc){
-  uint8_t cmdbuffer[128];
+  uint8_t cmdbuffer[PKTSIZE];
   uint8_t *bp = cmdbuffer;
   *bp++ = 1; // Command
 

radio.c

@@ -1,5 +1,5 @@
-// Core of 'radiod' program - control LOs, set frequency/mode, etc
-// Copyright 2018-2023, Phil Karn, KA9Q
+// Core of 'radiod' program - create/delete channels, control LOs, set frequency/mode, etc
+// Copyright 2018-2024, Phil Karn, KA9Q
 #define _GNU_SOURCE 1
 #include <assert.h>
 #include <stdlib.h>
@@ -388,7 +388,7 @@ void *sap_send(void *p){
   int const sess_version = 1;
 
   for(;;){
-    char message[1500],*wp;
+    char message[PKTSIZE],*wp;
     int space = sizeof(message);
     wp = message;
 
@@ -418,7 +418,7 @@ void *sap_send(void *p){
 
     {
       // Originator o=
-      char hostname[128];
+      char hostname[sysconf(_SC_HOST_NAME_MAX)];
       gethostname(hostname,sizeof(hostname));
 
       struct passwd pwd,*result = NULL;

spectrum.c

@@ -1,5 +1,5 @@
 // Spectral analysis service - far from complete - for ka9q-radio's radiod
-// Copyright 2023, Phil Karn, KA9Q
+// Copyright 2023-2024, Phil Karn, KA9Q
 #define _GNU_SOURCE 1
 #include <assert.h>
 #include <pthread.h>
@@ -20,7 +20,7 @@ void *demod_spectrum(void *arg){
 
   {
     char name[100];
-    snprintf(name,sizeof(name),"spect %u",chan->output.rtp.ssrc); // SSRC is dummy for ID, there's no RTP stream
+    snprintf(name,sizeof(name),"spect %u",chan->output.rtp.ssrc);
     pthread_setname(name);
   }
   pthread_mutex_init(&chan->status.lock,NULL);