From 1fd1be2cb63bebe21319deab9f95d94313f9507d Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Wed, 19 Aug 2020 22:23:27 -0400
Subject: [PATCH] Improvements to patty_ax25_sock_ack()

Changes:

    * Make patty_ax25_sock_ack() take a N(R) argument directly, rather
      than having the caller specify N(R)-1

    * Only perform acknowledgement of frames within the range between
      V(A) and N(R)-1
---
 include/patty/ax25/sock.h |  2 +-
 src/server.c              | 10 +++++-----
 src/sock.c                | 19 +++++++++++++------
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/include/patty/ax25/sock.h b/include/patty/ax25/sock.h
index 35d963b..6022781 100644
--- a/include/patty/ax25/sock.h
+++ b/include/patty/ax25/sock.h
@@ -234,7 +234,7 @@ ssize_t patty_ax25_sock_recv_pending(patty_ax25_sock *sock);
 
 ssize_t patty_ax25_sock_resend(patty_ax25_sock *sock, int seq);
 
-int patty_ax25_sock_ack(patty_ax25_sock *sock, int seq);
+int patty_ax25_sock_ack(patty_ax25_sock *sock, int nr);
 
 int patty_ax25_sock_ack_pending(patty_ax25_sock *sock);
 
diff --git a/src/server.c b/src/server.c
index b3281dc..b8b847c 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1502,7 +1502,7 @@ static int handle_i(patty_ax25_server *server,
         return frame->pf? reply_dm(iface, frame, PATTY_AX25_FRAME_FINAL): 0;
     }
 
-    patty_ax25_sock_ack(sock, frame->nr - 1);
+    patty_ax25_sock_ack(sock, frame->nr);
 
     if (patty_ax25_sock_ack_pending(sock) == 0) {
         patty_timer_stop(&sock->timer_t1);
@@ -1623,7 +1623,7 @@ static int handle_rr(patty_ax25_server *server,
         return 0;
     }
 
-    if (patty_ax25_sock_ack(sock, frame->nr - 1) > 0) {
+    if (patty_ax25_sock_ack(sock, frame->nr) > 0) {
 
     }
 
@@ -1671,7 +1671,7 @@ static int handle_rnr(patty_ax25_server *server,
         return 0;
     }
 
-    patty_ax25_sock_ack(sock, frame->nr - 1);
+    patty_ax25_sock_ack(sock, frame->nr);
 
     if (patty_ax25_sock_ack_pending(sock) == 0) {
         patty_timer_stop(&sock->timer_t1);
@@ -1716,7 +1716,7 @@ static int handle_rej(patty_ax25_server *server,
         return 0;
     }
 
-    patty_ax25_sock_ack(sock, frame->nr - 1);
+    patty_ax25_sock_ack(sock, frame->nr);
 
     end = sock->vs;
 
@@ -1743,7 +1743,7 @@ static int handle_srej(patty_ax25_server *server,
         return 0;
     }
 
-    patty_ax25_sock_ack(sock, frame->nr - 1);
+    patty_ax25_sock_ack(sock, frame->nr);
 
     /*
      * TODO: Read the fine print of section 4.3.2.4
diff --git a/src/sock.c b/src/sock.c
index 811be19..58e128f 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -689,21 +689,28 @@ ssize_t patty_ax25_sock_resend(patty_ax25_sock *sock, int seq) {
     return slot->len > 0? patty_ax25_if_send(sock->iface, buf, slot->len): 0;
 }
 
-int patty_ax25_sock_ack(patty_ax25_sock *sock, int seq) {
+int patty_ax25_sock_ack(patty_ax25_sock *sock, int nr) {
     int ret = 0,
+        min = sock->va,
+        max = nr,
         i;
 
-    for (i=0; i<sock->n_window_tx; i++) {
-        struct slot *slot = tx_slot(sock, seq - i);
+    if (max < min) {
+        max += sock->mode == PATTY_AX25_SOCK_SABME? 128: 8;
+    }
 
-        if (slot->len > 0) {
+    for (i=min; i<max; i++) {
+        struct slot *slot = tx_slot(sock, i);
+
+        if (slot->len > 0 && !slot->ack) {
             slot->ack = 1;
+
+            sock->va = tx_seq(sock, i);
+
             ret++;
         }
     }
 
-    sock->va = seq;
-
     return ret;
 }