From: Scott Worley <scottworley@scottworley.com>
Date: Tue, 10 Oct 2023 09:40:57 +0000 (-0700)
Subject: client: Change wire format!: Add epoch
X-Git-Tag: v0.1.0~22
X-Git-Url: http://git.scottworley.com/tattlekey/commitdiff_plain/8eacf88f138305f7bb8802367d80fa787d8830c4

client: Change wire format!: Add epoch

This helps the server de-dupe: Records with the same sequence number but
different epochs do not describe the same event.
---

diff --git a/client/net.c b/client/net.c
index 1e0790e..fa5d07b 100644
--- a/client/net.c
+++ b/client/net.c
@@ -20,6 +20,7 @@
 #include "config.h"
 
 #include "pico/cyw43_arch.h"
+#include "pico/rand.h"
 
 #include "lwip/pbuf.h"
 #include "lwip/udp.h"
@@ -27,11 +28,14 @@
 /* We only ever send to one address, and we only ever have one thread, so just
  * use one udp_pcb */
 static struct udp_pcb *the_pcb = NULL;
+static uint32_t epoch = 0;
 
-static void initialize_the_pcb() {
+static void net_local_init() {
   if (the_pcb)
     return;
 
+  epoch = get_rand_32();
+
   the_pcb = udp_new();
   if (!the_pcb)
     signal_error_by_blinking();
@@ -45,6 +49,7 @@ static void initialize_the_pcb() {
 }
 
 struct tattle_message_wire_format {
+  u32_t epoch;
   u16_t sender;
   u16_t seq;
   u32_t ago;
@@ -53,7 +58,7 @@ struct tattle_message_wire_format {
 void send_report_packet(u16_t seq, u32_t ago) {
   cyw43_arch_lwip_begin();
 
-  initialize_the_pcb();
+  net_local_init();
 
   struct pbuf *p = pbuf_alloc(
       PBUF_TRANSPORT, sizeof(struct tattle_message_wire_format), PBUF_RAM);
@@ -62,6 +67,7 @@ void send_report_packet(u16_t seq, u32_t ago) {
 
   struct tattle_message_wire_format *msg =
       (struct tattle_message_wire_format *)(p->payload);
+  msg->epoch = htonl(epoch);
   msg->sender = htons(config_this_tattler_identity);
   msg->seq = htons(seq);
   msg->ago = htonl(ago);