Enable multicast by default on 224.0.0.1 port 4532

Does not allow for rig control yet -- just rig info
https://github.com/Hamlib/Hamlib/issues/695

NEWS

@@ -13,6 +13,9 @@ Version 5.x -- future
         * Change FT1000MP Mark V model names to align with FT1000MP
 
 Version 4.6
+        * Hamlib now starts a multicast server that sends out rig information.  Does not receive commands yet.
+          See README.multicast
+
         * rigctld has new -b/bind-all option to try all interfaces -- restores original behavior.  This was done to fix duplicate rigctld instances on Windows
         * Yaesu rigs can now use send_morse to send keyer message 1-5 or a CW message up to 50 chars (which will use memory 1)
         * rig set level METER can now take SWR,COMP,ALC,IC/ID,DB,PO,VDD,TEMP arguments to set which meter to display

README.multicast

@@ -1,13 +1,69 @@
-Planned for version 5.0 -- comments/suggestions about this are more than welcome
+Planned for version 4.6 -- comments/suggestions about this are more than welcome
+Example of multicast packet as of 2023-10-20
+===================================================================
+{
+  "app": "Hamlib",
+  "version": "4.6~git 2023-10-20T16:52:59Z SHA=d87671",
+  "seq": 183,
+  "time": "2023-10-20T20:13:53.139869-0000",
+  "crc": 0,
+  "rig": {
+    "id": "FLRig:127.0.0.1:12345:30508",
+    "status": "OK",
+    "errorMsg": "",
+    "name": "FLRig",
+    "split": false,
+    "splitVfo": "VFOA",
+    "satMode": false,
+    "modelist": "AM CW USB LSB FM CWR PKTLSB PKTUSB "
+  },
+  "vfos": [
+    {
+      "name": "VFOA",
+      "freq": 14074270,
+      "mode": "PKTUSB",
+      "width": 3,
+      "ptt": false,
+      "rx": true,
+      "tx": true
+    },
+    {
+      "name": "VFOB",
+      "freq": 14074500,
+      "mode": "",
+      "width": 0,
+      "ptt": false,
+      "rx": false,
+      "tx": false
+    }
+  ],
+  "spectra": [
+    {
+      "id": 0,
+      "name": "?",
+      "type": "FIXED",
+      "minLevel": 0,
+      "maxLevel": 0,
+      "minStrength": 0,
+      "maxStrength": 0,
+      "centerFreq": 0,
+      "span": 0,
+      "lowFreq": 0,
+      "highFreq": 0,
+      "length": 0,
+      "data": ""
+    }
+  ]
+}
+===========================================================
 Multicast UDP broadcast containing rig snapshot data
 Bidirectional rig control and status
 Choice of token pairs or JSON
 All packets will be tagged with ID=[unique name] -- so multiple rigs can broadcast/rx on the same port
-Will be able to set freq, mode, width, ptt, satmode, and split to start since those are common to many apps.
+Will eventually be able to set freq, mode, width, ptt, satmode, and split to start since those are common to many apps.
 More functions will be added as time goes on.
 
 Broadcast packet contents to be based on get_rig_info output
-This will be the text format of name=value pairs
 Can be multiple VFO lines
 Parsers should allow for unknown tags that may be added in the future
 

src/rig.c

@@ -881,6 +881,7 @@ int HAMLIB_API rig_open(RIG *rig)
     value_t parm_value;
     //unsigned int net1, net2, net3, net4, net5, net6, net7, net8, port;
     int is_network = 0;
+    int retval = 0;
 
     ENTERFUNC2;
 
@@ -1450,7 +1451,7 @@ int HAMLIB_API rig_open(RIG *rig)
 
     if (rig->caps->get_freq)
     {
-        int retval = rig_get_freq(rig, RIG_VFO_A, &freq);
+        retval = rig_get_freq(rig, RIG_VFO_A, &freq);
 
         if (retval == RIG_OK && rig->caps->rig_model != RIG_MODEL_F6K)
         {
@@ -1484,6 +1485,21 @@ int HAMLIB_API rig_open(RIG *rig)
     memcpy(&rs->dcdport_deprecated, &rs->dcdport, sizeof(hamlib_port_t_deprecated));
     rig_flush_force(&rs->rigport, 1);
 //    if (rig->caps->rig_model != RIG_MODEL_NETRIGCTL) multicast_init(rig, "224.0.0.1", 4532);
+//    multicast_init(rig, "224.0.0.1", 4532);
+    char *multicast_addr = "224.0.0.1";
+    int multicast_port = 4532;
+    enum multicast_item_e items = RIG_MULTICAST_POLL | RIG_MULTICAST_TRANSCEIVE |
+                                  RIG_MULTICAST_SPECTRUM;
+    retval = network_multicast_publisher_start(rig, multicast_addr,
+              multicast_port, items);
+
+    if (retval != RIG_OK)
+    {
+        rig_debug(RIG_DEBUG_ERR, "%s: network_multicast_server failed: %s\n", __FILE__,
+                  rigerror(retval));
+        // we will consider this non-fatal for now
+    }
+
     RETURNFUNC2(RIG_OK);
 }
 

src/snapshot_data.c

@@ -1,5 +1,7 @@
+#include <sys/types.h>
+#define _XOPEN_SOURCE 700
+#include <unistd.h>
 #include <hamlib/config.h>
-
 #include <hamlib/rig.h>
 #include "misc.h"
 #include "snapshot_data.h"
@@ -19,8 +21,8 @@ static int snapshot_serialize_rig(cJSON *rig_node, RIG *rig)
     char buf[1024];
 
     // TODO: need to assign rig an ID, e.g. from command line
-    snprintf(buf, sizeof(buf), "%s:%s", rig->caps->model_name,
-         rig->state.rigport.pathname);
+    snprintf(buf, sizeof(buf), "%s:%s:%d", rig->caps->model_name,
+         rig->state.rigport.pathname, getpid());
 
     node = cJSON_AddStringToObject(rig_node, "id", buf);