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Posted to commits@nuttx.apache.org by GitBox <gi...@apache.org> on 2021/06/14 07:53:06 UTC
[GitHub] [incubator-nuttx] yamt commented on a change in pull request #3818: tcp: recv window update improvement
yamt commented on a change in pull request #3818:
URL: https://github.com/apache/incubator-nuttx/pull/3818#discussion_r650387042
##########
File path: net/tcp/tcp_recvwindow.c
##########
@@ -163,3 +163,80 @@ uint16_t tcp_get_recvwindow(FAR struct net_driver_s *dev,
return recvwndo;
}
+
+bool tcp_should_send_recvwindow(FAR struct tcp_conn_s *conn)
+{
+ FAR struct net_driver_s *dev = conn->dev;
+ uint16_t win;
+ size_t maxiob;
+ uint16_t maxwin;
+ uint16_t oldwin;
+ uint32_t rcvseq;
+ uint16_t adv;
+ uint16_t mss;
+
+ /* If the window shrunk, don't send. */
+
+ rcvseq = tcp_getsequence(conn->rcvseq);
+ if (TCP_SEQ_GTE(conn->rcv_adv, rcvseq))
Review comment:
ok
##########
File path: net/tcp/tcp_recvwindow.c
##########
@@ -163,3 +163,80 @@ uint16_t tcp_get_recvwindow(FAR struct net_driver_s *dev,
return recvwndo;
}
+
+bool tcp_should_send_recvwindow(FAR struct tcp_conn_s *conn)
+{
+ FAR struct net_driver_s *dev = conn->dev;
+ uint16_t win;
+ size_t maxiob;
+ uint16_t maxwin;
+ uint16_t oldwin;
+ uint32_t rcvseq;
+ uint16_t adv;
+ uint16_t mss;
+
+ /* If the window shrunk, don't send. */
+
+ rcvseq = tcp_getsequence(conn->rcvseq);
+ if (TCP_SEQ_GTE(conn->rcv_adv, rcvseq))
+ {
+ oldwin = TCP_SEQ_SUB(conn->rcv_adv, rcvseq);
+ }
+ else
+ {
+ /* This can happen for example when:
+ *
+ * - we shrunk the window
+ * - zero window probes advanced rcvseq
+ */
+
+ oldwin = 0;
+ }
+
+ win = tcp_get_recvwindow(dev, conn);
+ if (win <= oldwin)
+ {
+ return false;
+ }
+
+ adv = win - oldwin;
+
+ /* The following conditions are inspired from NetBSD TCP stack.
+ *
+ * - If we can extend the window by the half of the max possible size,
+ * send it.
+ *
+ * - If we can extend the window by 2 * mss, send it.
+ */
+
+ /* Calculate the max possible window size for the connection.
+ * This needs to be in sync with tcp_get_recvwindow().
+ */
+
+ maxiob = (CONFIG_IOB_NBUFFERS - CONFIG_IOB_THROTTLE) * CONFIG_IOB_BUFSIZE;
+ if (maxiob >= UINT16_MAX)
+ {
+ maxwin = UINT16_MAX;
+ }
+ else
+ {
+ maxwin = maxiob;
+ }
Review comment:
do you mean the maxwin calculation? i will.
##########
File path: net/tcp/tcp_recvwindow.c
##########
@@ -163,3 +163,80 @@ uint16_t tcp_get_recvwindow(FAR struct net_driver_s *dev,
return recvwndo;
}
+
+bool tcp_should_send_recvwindow(FAR struct tcp_conn_s *conn)
+{
+ FAR struct net_driver_s *dev = conn->dev;
+ uint16_t win;
+ size_t maxiob;
+ uint16_t maxwin;
+ uint16_t oldwin;
+ uint32_t rcvseq;
+ uint16_t adv;
+ uint16_t mss;
+
+ /* If the window shrunk, don't send. */
+
+ rcvseq = tcp_getsequence(conn->rcvseq);
+ if (TCP_SEQ_GTE(conn->rcv_adv, rcvseq))
Review comment:
done
##########
File path: net/tcp/tcp_recvwindow.c
##########
@@ -163,3 +163,80 @@ uint16_t tcp_get_recvwindow(FAR struct net_driver_s *dev,
return recvwndo;
}
+
+bool tcp_should_send_recvwindow(FAR struct tcp_conn_s *conn)
+{
+ FAR struct net_driver_s *dev = conn->dev;
+ uint16_t win;
+ size_t maxiob;
+ uint16_t maxwin;
+ uint16_t oldwin;
+ uint32_t rcvseq;
+ uint16_t adv;
+ uint16_t mss;
+
+ /* If the window shrunk, don't send. */
+
+ rcvseq = tcp_getsequence(conn->rcvseq);
+ if (TCP_SEQ_GTE(conn->rcv_adv, rcvseq))
+ {
+ oldwin = TCP_SEQ_SUB(conn->rcv_adv, rcvseq);
+ }
+ else
+ {
+ /* This can happen for example when:
+ *
+ * - we shrunk the window
+ * - zero window probes advanced rcvseq
+ */
+
+ oldwin = 0;
+ }
+
+ win = tcp_get_recvwindow(dev, conn);
+ if (win <= oldwin)
+ {
+ return false;
+ }
+
+ adv = win - oldwin;
+
+ /* The following conditions are inspired from NetBSD TCP stack.
+ *
+ * - If we can extend the window by the half of the max possible size,
+ * send it.
+ *
+ * - If we can extend the window by 2 * mss, send it.
+ */
+
+ /* Calculate the max possible window size for the connection.
+ * This needs to be in sync with tcp_get_recvwindow().
+ */
+
+ maxiob = (CONFIG_IOB_NBUFFERS - CONFIG_IOB_THROTTLE) * CONFIG_IOB_BUFSIZE;
+ if (maxiob >= UINT16_MAX)
+ {
+ maxwin = UINT16_MAX;
+ }
+ else
+ {
+ maxwin = maxiob;
+ }
Review comment:
done
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