From fcc75e49e1b50dc99b17200da99bb758384b3fde Mon Sep 17 00:00:00 2001
From: Mike Brady <4265913+mikebrady@users.noreply.github.com>
Date: Sun, 2 May 2021 14:40:39 +0100
Subject: [PATCH] Include the IP or the master in the shm -- the user might
 wish to check that it's in the timing peer list.

---
 nqptp-clock-sources.c    |  3 ++-
 nqptp-message-handlers.c |  4 +++-
 nqptp-shm-structures.h   |  3 ++-
 nqptp.c                  | 10 +++++++++-
 nqptp.h                  |  2 +-
 5 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/nqptp-clock-sources.c b/nqptp-clock-sources.c
index c32d424..009732a 100644
--- a/nqptp-clock-sources.c
+++ b/nqptp-clock-sources.c
@@ -205,7 +205,7 @@ void update_master() {
     if (old_master != -1) {
       // but there was a master clock, so remove it
       debug(1,"shm interface -- remove master clock designation");
-      update_master_clock_info(0, 0, 0);
+      update_master_clock_info(0, NULL, 0, 0);
     }
     if (timing_peer_count == 0)
       debug(2, "No timing peer list found");
@@ -217,6 +217,7 @@ void update_master() {
     // master_clock_index = best_so_far;
     if (old_master != best_so_far) {
       update_master_clock_info(clocks_private[best_so_far].clock_id,
+                               &clocks_private[best_so_far].ip,
                                clocks_private[best_so_far].local_time,
                                clocks_private[best_so_far].local_to_source_time_offset);
     }
diff --git a/nqptp-message-handlers.c b/nqptp-message-handlers.c
index 21cbaa4..448f860 100644
--- a/nqptp-message-handlers.c
+++ b/nqptp-message-handlers.c
@@ -494,7 +494,9 @@ void handle_delay_resp(char *buf, __attribute__((unused)) ssize_t recv_len,
       if (old_flags != clock_private_info->flags) {
         update_master();
       } else if ((clock_private_info->flags & (1 << clock_is_master)) != 0) {
-        update_master_clock_info(clock_private_info->clock_id, clock_private_info->local_time,
+        update_master_clock_info(clock_private_info->clock_id,
+                                 &clock_private_info->ip,
+                                 clock_private_info->local_time,
                                  clock_private_info->local_to_source_time_offset);
       }
 
diff --git a/nqptp-shm-structures.h b/nqptp-shm-structures.h
index f30f989..50d9e9a 100644
--- a/nqptp-shm-structures.h
+++ b/nqptp-shm-structures.h
@@ -22,7 +22,7 @@
 
 #define STORAGE_ID "/nqptp"
 #define MAX_CLOCKS 32
-#define NQPTP_SHM_STRUCTURES_VERSION 3
+#define NQPTP_SHM_STRUCTURES_VERSION 4
 #define NQPTP_CONTROL_PORT 9000
 
 // the control port will accept a UDP packet with the first letter being:
@@ -40,6 +40,7 @@ struct shm_structure {
   uint16_t version;          // check this is equal to NQPTP_SHM_STRUCTURES_VERSION
   uint32_t flags;            // unused
   uint64_t master_clock_id;  // the current master clock
+  char master_clock_ip[64];  // where it's coming from
   uint64_t local_time;       // the time when the offset was calculated
   uint64_t local_to_master_time_offset; // add this to the local time to get master clock time
 };
diff --git a/nqptp.c b/nqptp.c
index 04c5fb6..8db0faa 100644
--- a/nqptp.c
+++ b/nqptp.c
@@ -59,6 +59,10 @@
 #include <signal.h>
 #include <sys/epoll.h>
 
+#ifndef FIELD_SIZEOF
+#define FIELD_SIZEOF(t, f) (sizeof(((t *)0)->f))
+#endif
+
 // 8 samples per second
 
 #define BUFLEN 4096    // Max length of buffer
@@ -71,7 +75,7 @@ int master_clock_index = -1;
 struct shm_structure *shared_memory = NULL; // this is where public clock info is available
 int epoll_fd;
 
-void update_master_clock_info(uint64_t master_clock_id, uint64_t local_time,
+void update_master_clock_info(uint64_t master_clock_id, const char *ip, uint64_t local_time,
                               uint64_t local_to_master_offset) {
   if (shared_memory->master_clock_id != master_clock_id)
     debug(1, "Master clock is: %" PRIx64 ".", master_clock_id);
@@ -79,6 +83,10 @@ void update_master_clock_info(uint64_t master_clock_id, uint64_t local_time,
   if (rc != 0)
     warn("Can't acquire mutex to update master clock!");
   shared_memory->master_clock_id = master_clock_id;
+  if (ip != NULL)
+    strncpy((char *)&shared_memory->master_clock_ip, ip, FIELD_SIZEOF(struct shm_structure, master_clock_ip) - 1);
+  else
+    shared_memory->master_clock_ip[0] = '\0';
   shared_memory->local_time = local_time;
   shared_memory->local_to_master_time_offset = local_to_master_offset;
   rc = pthread_mutex_unlock(&shared_memory->shm_mutex);
diff --git a/nqptp.h b/nqptp.h
index 0e0d1d5..c1da9eb 100644
--- a/nqptp.h
+++ b/nqptp.h
@@ -31,7 +31,7 @@
 extern int master_clock_index;
 extern struct shm_structure *shared_memory;
 
-void update_master_clock_info(uint64_t master_clock_id, uint64_t local_time,
+void update_master_clock_info(uint64_t master_clock_id, const char *ip, uint64_t local_time,
                               uint64_t local_to_master_offset);
 
 #endif
\ No newline at end of file
-- 
2.47.2