Rename patty_ax25_sock sequences per Section 4.2.4

Changes:

    * Rename seq_send to vs, ie, V(S)

    * Rename seq_recv to vr, ie, V(R)

    * Ensure handling RR responses updates V(S) with the N(R) value of
      the received frame

include/patty/ax25/sock.h

@@ -83,8 +83,12 @@ typedef struct _patty_ax25_sock {
                 timer_t2,
                 timer_t3;
 
-    unsigned int seq_send,
-                 seq_recv;
+    /*
+     * AX.25 v2.2 Section 4.2.4 "Frame Variables and Sequence Numbers"
+     */
+    unsigned int vs,
+                 vr,
+                 va;
 
     size_t retries,
            pending;
@@ -129,9 +133,9 @@ char *patty_ax25_sock_pty(patty_ax25_sock *sock);
 int patty_ax25_sock_bind_if(patty_ax25_sock *sock,
                             patty_ax25_if *iface);
 
-void patty_ax25_sock_seq_send_incr(patty_ax25_sock *sock);
+void patty_ax25_sock_vs_incr(patty_ax25_sock *sock);
 
-void patty_ax25_sock_seq_recv_incr(patty_ax25_sock *sock);
+void patty_ax25_sock_vr_incr(patty_ax25_sock *sock);
 
 ssize_t patty_ax25_sock_send(patty_ax25_sock *sock,
                              enum patty_ax25_frame_cr cr,

src/server.c

@@ -1340,8 +1340,8 @@ static int handle_i(patty_ax25_server *server,
         return frame->pf? reply_dm(iface, frame, PATTY_AX25_FRAME_FINAL): 0;
     }
 
-    if (sock->seq_recv == frame->ns) {
-        patty_ax25_sock_seq_recv_incr(sock);
+    if (sock->vr == frame->ns) {
+        patty_ax25_sock_vr_incr(sock);
     } else {
         return patty_ax25_sock_send_rej(sock, PATTY_AX25_FRAME_RESPONSE, 1);
     }
@@ -1350,6 +1350,8 @@ static int handle_i(patty_ax25_server *server,
         goto error_write;
     }
 
+    sock->va = frame->ns + 1;
+
     if (++sock->pending == sock->n_window_rx / 2) {
         sock->pending = 0;
         patty_timer_stop(&sock->timer_t2);
@@ -1405,6 +1407,8 @@ static int handle_rr(patty_ax25_server *server,
             return patty_ax25_sock_send_rr(sock, PATTY_AX25_FRAME_RESPONSE, 1);
 
         case PATTY_AX25_FRAME_RESPONSE:
+            sock->vs = frame->nr;
+
             patty_timer_start(&sock->timer_t3, PATTY_AX25_SOCK_DEFAULT_KEEPALIVE);
 
         default:
@@ -1418,7 +1422,7 @@ static int handle_rej(patty_ax25_server *server,
                       patty_ax25_sock *sock,
                       patty_ax25_frame *frame) {
     unsigned int i,
-                 end = sock->seq_send;
+                 end = sock->vs;
 
     if (sock == NULL) {
         return 0;
@@ -1777,7 +1781,7 @@ static int handle_sock(uint32_t key,
         /*
          * NOTE: See AX.25 2.2, Section 6.4.1, "Sending I Frames"
          */
-        if (sock->seq_recv + sock->n_window_tx == sock->seq_send) {
+        if (sock->vs + sock->n_window_tx == sock->vs) {
             goto done;
         }
     }

src/sock.c

@@ -183,8 +183,9 @@ void patty_ax25_sock_init(patty_ax25_sock *sock) {
  * AX.25 v2.2 Specification, Section 6.5 "Resetting Procedure"
  */
 void patty_ax25_sock_reset(patty_ax25_sock *sock) {
-    sock->seq_send = 0;
-    sock->seq_recv = 0;
+    sock->vs      = 0;
+    sock->vr      = 0;
+    sock->va      = 0;
     sock->retries = sock->n_retry;
     sock->pending = 0;
 
@@ -329,19 +330,19 @@ error_if_promisc_add:
     return -1;
 }
 
-void patty_ax25_sock_seq_send_incr(patty_ax25_sock *sock) {
+void patty_ax25_sock_vs_incr(patty_ax25_sock *sock) {
     if (sock->mode == PATTY_AX25_SOCK_SABM) {
-        sock->seq_send = (sock->seq_send + 1) & 0x07;
+        sock->vs = (sock->vs + 1) & 0x07;
     } else {
-        sock->seq_send = (sock->seq_send + 1) & 0x7f;
+        sock->vs = (sock->vs + 1) & 0x7f;
     }
 }
 
-void patty_ax25_sock_seq_recv_incr(patty_ax25_sock *sock) {
+void patty_ax25_sock_vr_incr(patty_ax25_sock *sock) {
     if (sock->mode == PATTY_AX25_SOCK_SABM) {
-        sock->seq_recv = (sock->seq_recv + 1) & 0x07;
+        sock->vr = (sock->vr + 1) & 0x07;
     } else {
-        sock->seq_recv = (sock->seq_recv + 1) & 0x7f;
+        sock->vr = (sock->vr + 1) & 0x7f;
     }
 }
 
@@ -398,7 +399,7 @@ ssize_t patty_ax25_sock_send(patty_ax25_sock *sock,
     ssize_t encoded;
 
     uint8_t *buf = PATTY_AX25_FRAME_CONTROL_I(control)?
-        tx_slot_buf(sock, sock->seq_send): sock->tx_buf;
+        tx_slot_buf(sock, sock->vs): sock->tx_buf;
 
     if (sock->iface == NULL) {
         errno = ENETDOWN;
@@ -437,7 +438,7 @@ ssize_t patty_ax25_sock_send(patty_ax25_sock *sock,
 
         offset += infolen;
 
-        tx_slot_save_len(sock, sock->seq_send, offset);
+        tx_slot_save_len(sock, sock->vs, offset);
     }
 
     return patty_ax25_if_send(sock->iface, buf, offset);
@@ -462,13 +463,13 @@ ssize_t patty_ax25_sock_resend(patty_ax25_sock *sock,
 static uint16_t control_i(patty_ax25_sock *sock, int flag) {
     switch (sock->mode) {
         case PATTY_AX25_SOCK_SABM:
-            return ((sock->seq_recv & 0x07) << 5)
-                 | ((sock->seq_send & 0x07) << 1)
+            return ((sock->vr & 0x07) << 5)
+                 | ((sock->vs & 0x07) << 1)
                  | (flag << 4);
 
         case PATTY_AX25_SOCK_SABME:
-            return ((sock->seq_recv & 0x7f) << 9)
-                 | ((sock->seq_send & 0x7f) << 1)
+            return ((sock->vr & 0x7f) << 9)
+                 | ((sock->vs & 0x7f) << 1)
                  | (flag << 8);
 
         default:
@@ -481,12 +482,12 @@ static uint16_t control_s(patty_ax25_sock *sock,
                           int flag) {
     switch (sock->mode) {
         case PATTY_AX25_SOCK_SABM:
-            return ((sock->seq_recv & 0x07) << 5)
+            return ((sock->vr & 0x07) << 5)
                  | (type & 0x0f)
                  | (flag << 4);
 
         case PATTY_AX25_SOCK_SABME:
-            return ((sock->seq_recv & 0x7f) << 9)
+            return ((sock->vr & 0x7f) << 9)
                  | (type & 0x0f)
                  | (flag << 8);
 
@@ -634,7 +635,7 @@ ssize_t patty_ax25_sock_write(patty_ax25_sock *sock,
         goto error_send;
     }
 
-    patty_ax25_sock_seq_send_incr(sock);
+    patty_ax25_sock_vs_incr(sock);
 
     return len;