Implement SOCK_DGRAM

Implement PATTY_AX25_SOCK_DGRAM type sockets as a means of exchanging UI
frames between stations without requiring calling code to encode and
decode UI frames explicitly

include/patty/ax25/frame.h

@@ -59,8 +59,7 @@ enum patty_ax25_frame_type {
     PATTY_AX25_FRAME_FRMR    = 0x87,
     PATTY_AX25_FRAME_UI      = 0x03,
     PATTY_AX25_FRAME_XID     = 0xaf,
-    PATTY_AX25_FRAME_TEST    = 0xe3,
+    PATTY_AX25_FRAME_TEST    = 0xe3
-    PATTY_AX25_FRAME_UNKNOWN = 0xff
 };
 
 typedef struct _patty_ax25_frame {

include/patty/ax25/sock.h

@@ -39,6 +39,7 @@
 
 enum patty_ax25_sock_type {
     PATTY_AX25_SOCK_STREAM,
+    PATTY_AX25_SOCK_DGRAM,
     PATTY_AX25_SOCK_RAW
 };
 

src/frame.c

@@ -184,7 +184,7 @@ ssize_t patty_ax25_frame_decode_control(patty_ax25_frame *frame,
     frame->nr      = 0;
     frame->ns      = 0;
     frame->pf      = 0;
-    frame->type    = PATTY_AX25_FRAME_UNKNOWN;
+    frame->type    = 0xff;
     frame->proto   = PATTY_AX25_PROTO_UNKNOWN;
     frame->info    = NULL;
     frame->infolen = 0;

src/server.c

@@ -842,8 +842,6 @@ static int server_connect(patty_ax25_server *server,
      */
     memcpy(&sock->remote, &request.peer, sizeof(request.peer));
 
-    sock->state = PATTY_AX25_SOCK_PENDING_CONNECT;
-
     if (sock_save_remote(server, sock) < 0) {
         goto error_sock_save_remote;
     }
@@ -852,21 +850,34 @@ static int server_connect(patty_ax25_server *server,
         goto error_client_save_by_sock;
     }
 
+    switch (sock->type) {
+        case PATTY_AX25_SOCK_DGRAM:
+            sock->state = PATTY_AX25_SOCK_ESTABLISHED;
+
+            break;
+
+        case PATTY_AX25_SOCK_STREAM:
+            sock->state = PATTY_AX25_SOCK_PENDING_CONNECT;
+
             /*
-     * Send an XID frame, to attempt to negotiate AX.25 v2.2 and its default
+             * Send an XID frame, to attempt to negotiate AX.25 v2.2 and its
-     * parameters.
+             * default parameters.
              */
             if (patty_ax25_sock_send_xid(sock, PATTY_AX25_FRAME_COMMAND) < 0) {
                 return respond_connect(client, -1, errno);
             }
 
-    patty_timer_start(&sock->timer_t1, sock->n_ack);
-
             /*
              * At this point, we will wait for a DM, FRMR or XID response, which
-     * will help us determine what version of AX.25 to apply for this socket,
+             * will help us determine what version of AX.25 to apply for this
-     * or whether the peer is not accepting connections.
+             * socket, or whether the peer is not accepting connections.
              */
+            patty_timer_start(&sock->timer_t1, sock->n_ack);
+
+        default:
+            break;
+    }
+
     return 0;
 
 error_client_save_by_sock:
@@ -1396,6 +1407,17 @@ error_write:
     return -1;
 }
 
+static int handle_ui(patty_ax25_server *server,
+                     patty_ax25_if *iface,
+                     patty_ax25_sock *sock,
+                     patty_ax25_frame *frame) {
+    if (sock == NULL || sock->type != PATTY_AX25_SOCK_DGRAM) {
+        return 0;
+    }
+
+    return write(sock->fd, frame->info, frame->infolen);
+}
+
 static int handle_disc(patty_ax25_server *server,
                        patty_ax25_if *iface,
                        patty_ax25_sock *sock,
@@ -1690,6 +1712,7 @@ 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_UI:    return handle_ui(server, iface, sock, &frame);
         case PATTY_AX25_FRAME_RR:    return handle_rr(server, sock, &frame);
         case PATTY_AX25_FRAME_RNR:   return handle_rnr(server, sock, &frame);
         case PATTY_AX25_FRAME_REJ:   return handle_rej(server, sock, &frame);
@@ -1702,9 +1725,6 @@ static int handle_frame(patty_ax25_server *server,
         case PATTY_AX25_FRAME_DM:    return handle_dm(server, iface, sock, &frame);
         case PATTY_AX25_FRAME_DISC:  return handle_disc(server, iface, sock, &frame);
         case PATTY_AX25_FRAME_FRMR:  return handle_frmr(server, iface, sock, &frame);
-
-        default:
-            break;
     }
 
     return 0;

src/sock.c

@@ -111,26 +111,28 @@ error_realloc_tx_buf:
     return -1;
 }
 
-static patty_ax25_sock *init_raw(patty_ax25_sock *sock) {
+static patty_ax25_sock *init_dgram(patty_ax25_sock *sock,
-    if (bind_pty(sock) < 0) {
+                                   enum patty_ax25_proto proto) {
-        goto error_bind_pty;
+    sock->proto = proto;
+    sock->type  = PATTY_AX25_SOCK_DGRAM;
+
+    return sock;
 }
 
+static patty_ax25_sock *init_raw(patty_ax25_sock *sock) {
     if ((sock->raw = patty_kiss_tnc_new_fd(sock->fd)) == NULL) {
         goto error_kiss_tnc_new_fd;
     }
 
     sock->proto = PATTY_AX25_PROTO_NONE;
     sock->type  = PATTY_AX25_SOCK_RAW;
+    sock->state = PATTY_AX25_SOCK_ESTABLISHED;
 
     return sock;
 
 error_kiss_tnc_new_fd:
     (void)close(sock->fd);
 
-error_bind_pty:
-    free(sock);
-
     return NULL;
 }
 
@@ -144,11 +146,20 @@ patty_ax25_sock *patty_ax25_sock_new(enum patty_ax25_proto proto,
 
     memset(sock, '\0', sizeof(*sock));
 
-    if (type == PATTY_AX25_SOCK_RAW) {
+    if (bind_pty(sock) < 0) {
-        return init_raw(sock);
+        goto error_bind_pty;
     }
 
+    switch (type) {
+        case PATTY_AX25_SOCK_DGRAM:
+            return init_dgram(sock, proto);
+
+        case PATTY_AX25_SOCK_RAW:
+            return init_raw(sock);
+
+        case PATTY_AX25_SOCK_STREAM:
             patty_ax25_sock_init(sock);
+    }
 
     sock->proto         = proto;
     sock->type          = type;
@@ -160,18 +171,14 @@ patty_ax25_sock *patty_ax25_sock_new(enum patty_ax25_proto proto,
         goto error_init_bufs;
     }
 
-    if (bind_pty(sock) < 0) {
-        goto error_bind_pty;
-    }
-
     return sock;
 
-error_bind_pty:
 error_init_bufs:
     if (sock->tx_slots) free(sock->tx_slots);
     if (sock->rx_buf)   free(sock->rx_buf);
     if (sock->tx_buf)   free(sock->tx_buf);
 
+error_bind_pty:
     free(sock);
 
 error_malloc_sock:
@@ -577,6 +584,10 @@ static uint16_t control_i(patty_ax25_sock *sock, int flag) {
     }
 }
 
+static uint16_t control_ui(int flag) {
+    return PATTY_AX25_FRAME_UI | (flag << 4);
+}
+
 static uint16_t control_s(patty_ax25_sock *sock,
                           enum patty_ax25_frame_type type,
                           int flag) {
@@ -719,16 +730,14 @@ ssize_t patty_ax25_sock_write(patty_ax25_sock *sock,
                               size_t len) {
     uint16_t control;
 
-    if (sock->type == PATTY_AX25_SOCK_RAW) {
-        return patty_ax25_if_send(sock->iface, buf, len);
-    }
-
     if (sock->mode == PATTY_AX25_SOCK_DM) {
         errno = EBADF;
 
         goto error_invalid_mode;
     }
 
+    switch (sock->type) {
+        case PATTY_AX25_SOCK_STREAM:
             control = control_i(sock, 0);
 
             if (frame_send(sock, PATTY_AX25_FRAME_COMMAND, control, buf, len) < 0) {
@@ -737,6 +746,21 @@ ssize_t patty_ax25_sock_write(patty_ax25_sock *sock,
 
             patty_ax25_sock_vs_incr(sock);
 
+            break;
+
+        case PATTY_AX25_SOCK_DGRAM:
+            control = control_ui(0);
+
+            if (frame_send(sock, PATTY_AX25_FRAME_COMMAND, control, buf, len) < 0) {
+                goto error_frame_send;
+            }
+
+            break;
+
+        case PATTY_AX25_SOCK_RAW:
+            return patty_ax25_if_send(sock->iface, buf, len);
+    }
+
     return len;
 
 error_frame_send: