Changeset 0093ab6 in mainline for uspace/srv/net/tl/tcp/segment.c

Timestamp:

2011-09-21T19:56:41Z (14 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

032bbe7

Parents:

4c55a64

Message:

Parts of data reception. Trimming segment to receive window.

File:

• uspace/srv/net/tl/tcp/segment.c (modified) (2 diffs)

uspace/srv/net/tl/tcp/segment.c

@@ -35 +35 @@
  */
 
+#include <mem.h>
 #include <stdlib.h>
 #include "segment.h"
@@ -79 +80 @@
 }
 
-size_t tcp_segment_data_len(tcp_segment_t *seg)
+/** Trim segment to the specified interval.
+ *
+ * Trim any text or control whose sequence number is outside of [lo, hi)
+ * interval.
+ */
+void tcp_segment_trim(tcp_segment_t *seg, uint32_t left, uint32_t right)
+{
+        uint32_t t_size;
+
+        assert(left + right <= seg->len);
+
+        /* Special case, entire segment trimmed from left */
+        if (left == seg->len) {
+                seg->seq = seg->seq + seg->len;
+                seg->len = 0;
+                return;
+        }
+
+        /* Special case, entire segment trimmed from right */
+        if (right == seg->len) {
+                seg->len = 0;
+                return;
+        }
+
+        /* General case */
+
+        t_size = tcp_segment_text_size(seg);
+
+        if (left > 0 && (seg->ctrl & CTL_SYN) != 0) {
+                /* Trim SYN */
+                seg->ctrl &= ~CTL_SYN;
+                seg->seq++;
+                seg->len--;
+                left--;
+        }
+
+        if (right > 0 && (seg->ctrl & CTL_FIN) != 0) {
+                /* Trim FIN */
+                seg->ctrl &= ~CTL_FIN;
+                seg->len--;
+                right--;
+        }
+
+        if (left > 0 || right > 0) {
+                /* Trim segment text */
+                assert(left + right <= t_size);
+
+                seg->data += left;
+                seg->len -= left + right;
+        }
+}
+
+/** Copy out text data from segment.
+ *
+ */
+void tcp_segment_text_copy(tcp_segment_t *seg, void *buf, size_t size)
+{
+        assert(size <= tcp_segment_text_size(seg));
+        memcpy(buf, seg->data, size);
+}
+
+/** Return number of bytes in segment text. */
+size_t tcp_segment_text_size(tcp_segment_t *seg)
 {
         return seg->len - seq_no_control_len(seg->ctrl);