Keep separate TX, RX single buffers in socks

Changes:

    * Replace patty_ax25_sock member 'buf' with 'tx_buf' and 'rx_buf'
      for transmitting or receiving single, non-sequential packets

    * Make patty_ax25_sock_upgrade() reallocate all I/O buffers based on
      window size and MTU/MRU, useful when entering SABME mode

include/patty/ax25/sock.h

@@ -70,7 +70,9 @@ typedef struct _patty_ax25_sock {
     int fd;
     char path[PATTY_AX25_SOCK_PATH_SIZE];
 
-    void *buf;
+    void *tx_buf,
+         *rx_buf;
+
     void *tx_slots;
 
     patty_ax25_if *iface;
@@ -87,10 +89,10 @@ patty_ax25_sock *patty_ax25_sock_new(enum patty_ax25_proto proto,
 
 void patty_ax25_sock_reset(patty_ax25_sock *sock);
 
-void patty_ax25_sock_upgrade(patty_ax25_sock *sock);
-
 void patty_ax25_sock_destroy(patty_ax25_sock *sock);
 
+int patty_ax25_sock_upgrade(patty_ax25_sock *sock);
+
 int patty_ax25_sock_params_set(patty_ax25_sock *sock,
                                patty_ax25_params *params);
 

src/server.c

@@ -1528,7 +1528,7 @@ static int handle_sock(uint32_t key,
         goto done;
     }
 
-    if ((len = read(sock->fd, sock->buf, sock->n_maxlen_rx)) < 0) {
+    if ((len = read(sock->fd, sock->rx_buf, sock->n_maxlen_rx)) < 0) {
         if (errno == EIO) {
             (void)sock_close(server, sock);
 
@@ -1542,7 +1542,7 @@ static int handle_sock(uint32_t key,
         goto done;
     }
 
-    if (patty_ax25_sock_write(sock, sock->buf, len) < 0) {
+    if (patty_ax25_sock_write(sock, sock->rx_buf, len) < 0) {
         goto error_sock_write;
     }
 

src/sock.c

@@ -54,7 +54,7 @@ error_open:
     return -1;
 }
 
-static inline size_t tx_bufsz(patty_ax25_sock *sock) {
+static inline size_t bufsz(patty_ax25_sock *sock) {
     return PATTY_AX25_FRAME_OVERHEAD + sock->n_maxlen_tx;
 }
 
@@ -71,8 +71,12 @@ static inline void *tx_slot(patty_ax25_sock *sock, size_t i) {
 }
 
 static int init_bufs(patty_ax25_sock *sock) {
-    if ((sock->buf = realloc(sock->buf, tx_bufsz(sock))) == NULL) {
+    if ((sock->tx_buf = realloc(sock->tx_buf, bufsz(sock))) == NULL) {
-        goto error_realloc_buf;
+        goto error_realloc_tx_buf;
+    }
+
+    if ((sock->rx_buf = realloc(sock->rx_buf, bufsz(sock))) == NULL) {
+        goto error_realloc_rx_buf;
     }
 
     if ((sock->tx_slots = realloc(sock->tx_slots, tx_slots_size(sock))) == NULL) {
@@ -82,11 +86,14 @@ static int init_bufs(patty_ax25_sock *sock) {
     return 0;
 
 error_realloc_tx_slots:
-    free(sock->buf);
+    free(sock->rx_buf);
+    sock->rx_buf = NULL;
 
-    sock->buf = NULL;
+error_realloc_rx_buf:
+    free(sock->tx_buf);
+    sock->tx_buf = NULL;
 
-error_realloc_buf:
+error_realloc_tx_buf:
     return -1;
 }
 
@@ -121,7 +128,8 @@ patty_ax25_sock *patty_ax25_sock_new(enum patty_ax25_proto proto,
 error_bind_pty:
 error_init_bufs:
     if (sock->tx_slots) free(sock->tx_slots);
-    if (sock->buf)      free(sock->buf);
+    if (sock->rx_buf)   free(sock->rx_buf);
+    if (sock->tx_buf)   free(sock->tx_buf);
 
     free(sock);
 
@@ -145,15 +153,6 @@ void patty_ax25_sock_reset(patty_ax25_sock *sock) {
     sock->seq_recv        = 0;
 }
 
-void patty_ax25_sock_upgrade(patty_ax25_sock *sock) {
-    sock->version     = PATTY_AX25_2_2;
-    sock->flags_hdlc  = PATTY_AX25_SOCK_2_2_DEFAULT_HDLC;
-    sock->n_maxlen_tx = PATTY_AX25_SOCK_2_2_DEFAULT_MAXLEN;
-    sock->n_maxlen_rx = PATTY_AX25_SOCK_2_2_DEFAULT_MAXLEN;
-    sock->n_window_tx = PATTY_AX25_SOCK_2_2_DEFAULT_WINDOW;
-    sock->n_window_rx = PATTY_AX25_SOCK_2_2_DEFAULT_WINDOW;
-}
-
 void patty_ax25_sock_destroy(patty_ax25_sock *sock) {
     if (sock->fd) {
         if (sock->iface) {
@@ -163,11 +162,23 @@ void patty_ax25_sock_destroy(patty_ax25_sock *sock) {
         close(sock->fd);
     }
 
-    free(sock->buf);
     free(sock->tx_slots);
+    free(sock->rx_buf);
+    free(sock->tx_buf);
     free(sock);
 }
 
+int patty_ax25_sock_upgrade(patty_ax25_sock *sock) {
+    sock->version     = PATTY_AX25_2_2;
+    sock->flags_hdlc  = PATTY_AX25_SOCK_2_2_DEFAULT_HDLC;
+    sock->n_maxlen_tx = PATTY_AX25_SOCK_2_2_DEFAULT_MAXLEN;
+    sock->n_maxlen_rx = PATTY_AX25_SOCK_2_2_DEFAULT_MAXLEN;
+    sock->n_window_tx = PATTY_AX25_SOCK_2_2_DEFAULT_WINDOW;
+    sock->n_window_rx = PATTY_AX25_SOCK_2_2_DEFAULT_WINDOW;
+
+    return init_bufs(sock);
+}
+
 int patty_ax25_sock_params_set(patty_ax25_sock *sock,
                                patty_ax25_params *params) {
     if (params->flags & PATTY_AX25_PARAM_CLASSES) {
@@ -350,13 +361,13 @@ ssize_t patty_ax25_sock_send(patty_ax25_sock *sock,
     ssize_t encoded;
 
     uint8_t *buf = PATTY_AX25_FRAME_CONTROL_U(control)?
-        sock->buf: tx_slot(sock, sock->seq_send);
+        sock->tx_buf: tx_slot(sock, sock->seq_send);
 
     if (toobig(sock, infolen)) {
         goto error_toobig;
     }
 
-    if ((encoded = encode_address(sock, cr, buf, tx_bufsz(sock))) < 0) {
+    if ((encoded = encode_address(sock, cr, buf, bufsz(sock))) < 0) {
         goto error_encode_address;
     } else {
         offset += encoded;