From: Scott Worley <scottworley@scottworley.com>
Date: Tue, 10 Oct 2023 09:27:57 +0000 (-0700)
Subject: client: Change wire format!: Expand `ago` field: 16 bits → 32 bits
X-Git-Tag: v0.1.0~23
X-Git-Url: http://git.scottworley.com/tattlekey/commitdiff_plain/9266b741959871619b5431a2b4e4ebdad5567a3d

client: Change wire format!: Expand `ago` field: 16 bits → 32 bits

16-bit values of seconds only go up to 18 hours, and sometimes a little
more than that would be nice.

32 is overkill.  24 would have been fine, but would have been slightly
annoying to encode and parse.
---

diff --git a/client/config.c b/client/config.c
index 61d64ce..a708df4 100644
--- a/client/config.c
+++ b/client/config.c
@@ -39,12 +39,7 @@ const u32_t config_minimum_seconds_between_button_presses = 1;
  *   etc.
  * This provides some robustness against network outages, automatically
  * replaying the log periodically to be collected after connectivity
- * is restored.
- *
- * Values above 17 are currently not recommended because the current
- * wire format uses a 16-bit field for a duration in seconds, which wraps
- * at 18 hours.
- *   */
+ * is restored. */
 const uint config_resend_count = 16;
 
 /* These control the size of the per-send-count press queues.
diff --git a/client/config.h b/client/config.h
index 8d23169..3a61793 100644
--- a/client/config.h
+++ b/client/config.h
@@ -59,12 +59,7 @@ extern const u32_t config_minimum_seconds_between_button_presses;
  *   etc.
  * This provides some robustness against network outages, automatically
  * replaying the log periodically to be collected after connectivity
- * is restored.
- *
- * Values above 17 are currently not recommended because the current
- * wire format uses a 16-bit field for a duration in seconds, which wraps
- * at 18 hours.
- *   */
+ * is restored. */
 extern const uint config_resend_count;
 
 /* These control the size of the per-send-count press queues.
diff --git a/client/net.c b/client/net.c
index 6253d61..1e0790e 100644
--- a/client/net.c
+++ b/client/net.c
@@ -47,10 +47,10 @@ static void initialize_the_pcb() {
 struct tattle_message_wire_format {
   u16_t sender;
   u16_t seq;
-  u16_t ago;
+  u32_t ago;
 };
 
-void send_report_packet(u16_t seq, u16_t ago) {
+void send_report_packet(u16_t seq, u32_t ago) {
   cyw43_arch_lwip_begin();
 
   initialize_the_pcb();
@@ -64,7 +64,7 @@ void send_report_packet(u16_t seq, u16_t ago) {
       (struct tattle_message_wire_format *)(p->payload);
   msg->sender = htons(config_this_tattler_identity);
   msg->seq = htons(seq);
-  msg->ago = htons(ago);
+  msg->ago = htonl(ago);
 
   if (udp_send(the_pcb, p) != ERR_OK)
     signal_error_by_blinking();
diff --git a/client/net.h b/client/net.h
index 30a6e03..9b8fc1f 100644
--- a/client/net.h
+++ b/client/net.h
@@ -20,6 +20,6 @@
 
 #include "lwip/arch.h"
 
-void send_report_packet(u16_t seq, u16_t ago);
+void send_report_packet(u16_t seq, u32_t ago);
 
 #endif
diff --git a/client/tattlekey.c b/client/tattlekey.c
index 9d25585..f9b74c1 100644
--- a/client/tattlekey.c
+++ b/client/tattlekey.c
@@ -94,7 +94,7 @@ void service_sleeps(int alarm, press_pile_t *pp) {
     press_t press;
     if (!get_press_due_for_resend(pp, now, &press))
       signal_error_by_blinking();
-    uint32_t ago = now - press.timestamp;
+    u32_t ago = now - press.timestamp;
     send_report_packet(press.seq, ago);
     press.send_count++;
     if (press.send_count < config_resend_count) {