From 1eb3d096080df207dc256629c95d25eafb2d200d Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Thu, 16 Jul 2020 00:14:21 -0400
Subject: [PATCH] Handle receipt of REJ, SREJ frames

Utilizing the sock TX ring buffer, respond to peer requests to resend
certain numbered I frames indicated by REJ and SREJ frames
---
 src/server.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/server.c b/src/server.c
index 5a7d06d..a012da9 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1276,6 +1276,41 @@ error_sock_delete:
     return -1;
 }
 
+static int handle_rej(patty_ax25_server *server,
+                      patty_ax25_if *iface,
+                      patty_ax25_sock *sock,
+                      patty_ax25_frame *frame) {
+    unsigned int i;
+
+    for (i=frame->nr; i<sock->seq_send; i++) {
+        if (patty_ax25_sock_resend(sock, i) < 0) {
+            goto error_sock_resend;
+        }
+    }
+
+    return 0;
+
+error_sock_resend:
+    return -1;
+}
+
+static int handle_srej(patty_ax25_server *server,
+                       patty_ax25_if *iface,
+                       patty_ax25_sock *sock,
+                       patty_ax25_frame *frame) {
+    /*
+     * TODO: Read the fine print of section 4.3.2.4
+     */
+    if (patty_ax25_sock_resend(sock, frame->nr) < 0) {
+        goto error_sock_resend;
+    }
+
+    return 0;
+
+error_sock_resend:
+    return -1;
+}
+
 static int handle_frame(patty_ax25_server *server,
                         patty_ax25_if *iface,
                         void *buf,
@@ -1307,12 +1342,14 @@ static int handle_frame(patty_ax25_server *server,
     }
 
     switch (frame.type) {
-        case PATTY_AX25_FRAME_I:     return handle_i(server, iface, sock, &frame);
         case PATTY_AX25_FRAME_UA:    return handle_ua(server, iface, &frame);
         case PATTY_AX25_FRAME_DM:    return handle_dm(server, iface, &frame);
         case PATTY_AX25_FRAME_SABM:
         case PATTY_AX25_FRAME_SABME: return handle_sabm(server, iface, &frame);
         case PATTY_AX25_FRAME_DISC:  return handle_disc(server, iface, &frame);
+        case PATTY_AX25_FRAME_I:     return handle_i(server, iface, sock, &frame);
+        case PATTY_AX25_FRAME_REJ:   return handle_rej(server, iface, sock, &frame);
+        case PATTY_AX25_FRAME_SREJ:  return handle_srej(server, iface, sock, &frame);
         case PATTY_AX25_FRAME_FRMR:  return 0;
 
         default: