Fixed bug #10088: Correctly implemented shutdown at socket level.

CHANGELOG

@@ -225,6 +225,10 @@ HISTORY
 
   ++ Bugfixes:
 
+  2010-06-24: Simon Goldschmidt
+  * api(_lib).c/.h, api_msg.c/.h, sockets.c/.h: Fixed bug #10088: Correctly
+    implemented shutdown at socket level.
+
   2010-06-21: Simon Goldschmidt
   * pbuf.c/.h, ip_frag.c/.h, opt.h, memp_std.h: Fixed bug #29361 (ip_frag has
     problems with zero-copy DMA MACs) by adding custom pbufs and implementing

src/api/api_lib.c

@@ -600,13 +600,14 @@ netconn_write(struct netconn *conn, const void *dataptr, size_t size, u8_t apifl
 }
 
 /**
- * Close a TCP netconn (doesn't delete it).
+ * Close ot shutdown a TCP netconn (doesn't delete it).
  *
- * @param conn the TCP netconn to close
+ * @param conn the TCP netconn to close or shutdown
+ * @param how fully close or only shutdown one side?
  * @return ERR_OK if the netconn was closed, any other err_t on error
  */
-err_t
-netconn_close(struct netconn *conn)
+static err_t
+netconn_close_shutdown(struct netconn *conn, u8_t how)
 {
   struct api_msg msg;
   err_t err;
@@ -615,6 +616,8 @@ netconn_close(struct netconn *conn)
 
   msg.function = do_close;
   msg.msg.conn = conn;
+  /* shutting down both ends is the same as closing */
+  msg.msg.msg.sd.shut = how;
   /* because of the LWIP_TCPIP_CORE_LOCKING implementation of do_close,
      don't use TCPIP_APIMSG here */
   err = tcpip_apimsg(&msg);
@@ -623,6 +626,31 @@ netconn_close(struct netconn *conn)
   return err;
 }
 
+/**
+ * Close a TCP netconn (doesn't delete it).
+ *
+ * @param conn the TCP netconn to close
+ * @return ERR_OK if the netconn was closed, any other err_t on error
+ */
+err_t
+netconn_close(struct netconn *conn)
+{
+  /* shutting down both ends is the same as closing */
+  return netconn_close_shutdown(conn, NETCONN_SHUT_RDWR);
+}
+
+/**
+ * Shut down one or both sides of a TCP netconn (doesn't delete it).
+ *
+ * @param conn the TCP netconn to shut down
+ * @return ERR_OK if the netconn was closed, any other err_t on error
+ */
+err_t
+netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx)
+{
+  return netconn_close_shutdown(conn, (shut_rx ? NETCONN_SHUT_RD : 0) | (shut_tx ? NETCONN_SHUT_WR : 0));
+}
+
 #if LWIP_IGMP
 /**
  * Join multicast groups for UDP netconns.

src/api/api_msg.c

@@ -729,6 +729,7 @@ static void
 do_close_internal(struct netconn *conn)
 {
   err_t err;
+  u8_t shut, shut_rx, shut_tx, close;
 
   LWIP_ASSERT("invalid conn", (conn != NULL));
   LWIP_ASSERT("this is for tcp netconns only", (conn->type == NETCONN_TCP));
@@ -736,20 +737,38 @@ do_close_internal(struct netconn *conn)
   LWIP_ASSERT("pcb already closed", (conn->pcb.tcp != NULL));
   LWIP_ASSERT("conn->current_msg != NULL", conn->current_msg != NULL);
 
+  shut = conn->current_msg->msg.sd.shut;
+  shut_rx = shut & NETCONN_SHUT_RD;
+  shut_tx = shut & NETCONN_SHUT_WR;
+  /* shutting down both ends is the same as closing */
+  close = shut == NETCONN_SHUT_RDWR;
+
   /* Set back some callback pointers */
-  tcp_arg(conn->pcb.tcp, NULL);
+  if (close) {
+    tcp_arg(conn->pcb.tcp, NULL);
+  }
   if (conn->pcb.tcp->state == LISTEN) {
     tcp_accept(conn->pcb.tcp, NULL);
   } else {
-    tcp_recv(conn->pcb.tcp, NULL);
-    tcp_accept(conn->pcb.tcp, NULL);
     /* some callbacks have to be reset if tcp_close is not successful */
-    tcp_sent(conn->pcb.tcp, NULL);
-    tcp_poll(conn->pcb.tcp, NULL, 4);
-    tcp_err(conn->pcb.tcp, NULL);
+    if (shut_rx) {
+      tcp_recv(conn->pcb.tcp, NULL);
+      tcp_accept(conn->pcb.tcp, NULL);
+    }
+    if (shut_tx) {
+      tcp_sent(conn->pcb.tcp, NULL);
+    }
+    if (close) {
+      tcp_poll(conn->pcb.tcp, NULL, 4);
+      tcp_err(conn->pcb.tcp, NULL);
+    }
   }
   /* Try to close the connection */
-  err = tcp_close(conn->pcb.tcp);
+  if (shut == NETCONN_SHUT_RDWR) {
+    err = tcp_close(conn->pcb.tcp);
+  } else {
+    err = tcp_shutdown(conn->pcb.tcp, shut & NETCONN_SHUT_RD, shut & NETCONN_SHUT_WR);
+  }
   if (err == ERR_OK) {
     /* Closing succeeded */
     conn->current_msg->err = ERR_OK;
@@ -759,9 +778,15 @@ do_close_internal(struct netconn *conn)
     conn->pcb.tcp = NULL;
     /* Trigger select() in socket layer. Make sure everybody notices activity
        on the connection, error first! */
-    API_EVENT(conn, NETCONN_EVT_ERROR, 0);
-    API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
-    API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+    if (close) {
+      API_EVENT(conn, NETCONN_EVT_ERROR, 0);
+    }
+    if (shut_rx) {
+      API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
+    }
+    if (shut_tx) {
+      API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+    }
     /* wake up the application task */
     sys_sem_signal(&conn->op_completed);
   } else {
@@ -772,6 +797,7 @@ do_close_internal(struct netconn *conn)
     tcp_poll(conn->pcb.tcp, poll_tcp, 4);
     tcp_err(conn->pcb.tcp, err_tcp);
     tcp_arg(conn->pcb.tcp, conn);
+    /* don't restore recv callback: we don't want to receive any more data */
   }
   /* If closing didn't succeed, we get called again either
      from poll_tcp or from sent_tcp */
@@ -1401,15 +1427,22 @@ do_close(struct api_msg_msg *msg)
     LWIP_ASSERT("msg->conn->type == NETCONN_TCP", msg->conn->type == NETCONN_TCP);
     msg->err = ERR_INPROGRESS;
   } else if ((msg->conn->pcb.tcp != NULL) && (msg->conn->type == NETCONN_TCP)) {
-    /* Drain and delete mboxes */
-    netconn_drain(msg->conn);
-    LWIP_ASSERT("already writing or closing", msg->conn->current_msg == NULL &&
-      msg->conn->write_offset == 0);
-    msg->conn->state = NETCONN_CLOSE;
-    msg->conn->current_msg = msg;
-    do_close_internal(msg->conn);
-    /* for tcp netconns, do_close_internal ACKs the message */
-    return;
+    if ((msg->msg.sd.shut != NETCONN_SHUT_RDWR) && (msg->conn->state == NETCONN_LISTEN)) {
+      /* LISTEN doesn't support half shutdown */
+      msg->err = ERR_CONN;
+    } else {
+      if (msg->msg.sd.shut & NETCONN_SHUT_RD) {
+        /* Drain and delete mboxes */
+        netconn_drain(msg->conn);
+      }
+      LWIP_ASSERT("already writing or closing", msg->conn->current_msg == NULL &&
+        msg->conn->write_offset == 0);
+      msg->conn->state = NETCONN_CLOSE;
+      msg->conn->current_msg = msg;
+      do_close_internal(msg->conn);
+      /* for tcp netconns, do_close_internal ACKs the message */
+      return;
+    }
   } else
 #endif /* LWIP_TCP */
   {

src/api/sockets.c

@@ -1344,9 +1344,42 @@ event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len)
 int
 lwip_shutdown(int s, int how)
 {
-  LWIP_UNUSED_ARG(how);
+  struct lwip_sock *sock;
+  err_t err;
+  u8_t shut_rx = 0, shut_tx = 0;
+
   LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_shutdown(%d, how=%d)\n", s, how));
-  return lwip_close(s); /* XXX temporary hack until proper implementation */
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  if (sock->conn != NULL) {
+    if (netconn_type(sock->conn) != NETCONN_TCP) {
+      sock_set_errno(sock, EOPNOTSUPP);
+      return EOPNOTSUPP;
+    }
+  } else {
+    sock_set_errno(sock, ENOTCONN);
+    return ENOTCONN;
+  }
+
+  if (how == SHUT_RD) {
+    shut_rx = 1;
+  } else if (how == SHUT_WR) {
+    shut_tx = 1;
+  } else if(how == SHUT_RDWR) {
+    shut_rx = 1;
+    shut_tx = 1;
+  } else {
+    sock_set_errno(sock, EINVAL);
+    return EINVAL;
+  }
+  err = netconn_shutdown(sock->conn, shut_rx, shut_tx);
+
+  sock_set_errno(sock, err_to_errno(err));
+  return (err == ERR_OK ? 0 : -1);
 }
 
 static int

src/include/lwip/api.h

@@ -234,6 +234,7 @@ err_t   netconn_send(struct netconn *conn, struct netbuf *buf);
 err_t   netconn_write(struct netconn *conn, const void *dataptr, size_t size,
                       u8_t apiflags);
 err_t   netconn_close(struct netconn *conn);
+err_t   netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx);
 
 #if LWIP_IGMP
 err_t   netconn_join_leave_group(struct netconn *conn, ip_addr_t *multiaddr,

src/include/lwip/api_msg.h

@@ -48,6 +48,10 @@
 extern "C" {
 #endif
 
+#define NETCONN_SHUT_RD   1
+#define NETCONN_SHUT_WR   2
+#define NETCONN_SHUT_RDWR 3
+
 /* IP addresses and port numbers are expected to be in
  * the same byte order as in the corresponding pcb.
  */
@@ -89,6 +93,10 @@ struct api_msg_msg {
     struct {
       u32_t len;
     } r;
+    /** used for do_close (/shutdown) */
+    struct {
+      u8_t shut;
+    } sd;
 #if LWIP_IGMP
     /** used for do_join_leave_group */
     struct {
@@ -144,6 +152,7 @@ void do_recv            ( struct api_msg_msg *msg);
 void do_write           ( struct api_msg_msg *msg);
 void do_getaddr         ( struct api_msg_msg *msg);
 void do_close           ( struct api_msg_msg *msg);
+void do_shutdown        ( struct api_msg_msg *msg);
 #if LWIP_IGMP
 void do_join_leave_group( struct api_msg_msg *msg);
 #endif /* LWIP_IGMP */

src/include/lwip/sockets.h

@@ -279,6 +279,12 @@ typedef struct ip_mreq {
 #define O_NDELAY    1 /* same as O_NONBLOCK, for compatibility */
 #endif
 
+#ifndef SHUT_RD
+  #define SHUT_RD   1
+  #define SHUT_WR   2
+  #define SHUT_RDWR 3
+#endif
+
 /* FD_SET used for lwip_select */
 #ifndef FD_SET
   #undef  FD_SETSIZE