From 70c7a8f590c8d4cb9d3d4734cd70b47086a065c4 Mon Sep 17 00:00:00 2001
From: Shawn Nock <shawn@monadnock.ca>
Date: Fri, 2 Aug 2019 16:03:45 -0400
Subject: [PATCH] Works around weird initial rules for H5 state machine
 (initial ack must be 0?)

---
 src/main.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/main.c b/src/main.c
index e9647c3..751ebfd 100644
--- a/src/main.c
+++ b/src/main.c
@@ -140,6 +140,7 @@ static struct h5 {
 		PAYLOAD,
 		END,
 	}			rx_state;
+	bool initializing;
 } h5;
 
 //static u8_t unack_queue_len;
@@ -547,7 +548,13 @@ static void unproc_thread(void) {
             LOG_DBG("Header: seq %d, ack %d, rel: %s, has_crc16: %s", hdr.seq, hdr.ack,
                     hdr.is_reliable ? "true" : "false",
                     hdr.crc_after_payload ? "true" : "false");
-            u8_t expected_seq = next_seq(h5.last_seen_seq_from_host);
+            u8_t expected_seq;
+            if (h5.initializing) {
+                expected_seq = 0;
+                h5.initializing = false;
+            } else {
+                expected_seq = next_seq(h5.last_seen_seq_from_host);
+            }
             if (hdr.seq != expected_seq) {
                 LOG_ERR("Seq expected %u got %u. Drop packet", expected_seq, hdr.seq);
                 goto next;
@@ -882,8 +889,9 @@ static linkstate_t do_init(struct net_buf const *buf) {
         return INIT;
     case H5_CONFIG_RESPONSE:
         h5.tx_win = conf_rsp[2] & 0x7;
-        h5.last_seen_seq_from_host = 7;
+        h5.last_seen_seq_from_host = 0;
         h5.local_seq = 0;
+        h5.initializing = true;
         LOG_DBG("Finished H5 configuration, tx_win %u: INIT -> ACTIVE", h5.tx_win);
         return ACTIVE;
     default: