Changeset 0093ab6 in mainline

Timestamp:

2011-09-21T19:56:41Z (13 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.

Location:

uspace/srv/net/tl/tcp

Files:

• conn.c (modified) (10 diffs)
• conn.h (modified) (1 diff)
• header.c (modified) (1 diff)
• segment.c (modified) (2 diffs)
• segment.h (modified) (2 diffs)
• seq_no.c (modified) (3 diffs)
• seq_no.h (modified) (1 diff)
• tcp_type.h (modified) (2 diffs)

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

@@ -38 +38 @@
 #include <errno.h>
 #include <io/log.h>
+#include <macros.h>
 #include <stdlib.h>
 #include "conn.h"
@@ -46 +47 @@
 #include "tqueue.h"
 
+#define RCV_BUF_SIZE 4096
+
 LIST_INITIALIZE(conn_list);
 
@@ -54 +57 @@
         tcp_conn_t *conn;
 
+        /* Allocate connection structure */
         conn = calloc(1, sizeof(tcp_conn_t));
         if (conn == NULL)
                 return NULL;
 
+        /* Allocate receive buffer */
+        conn->rcv_buf_size = RCV_BUF_SIZE;
+        conn->rcv_buf_used = 0;
+        conn->rcv_buf = calloc(1, conn->rcv_buf_size);
+        if (conn->rcv_buf == NULL) {
+                free(conn);
+                return NULL;
+        }
+
+        /* Set up receive window. */
+        conn->rcv_wnd = conn->rcv_buf_size;
+
+        /* Initialize incoming segment queue */
         tcp_iqueue_init(&conn->incoming, conn);
 
@@ -175 +192 @@
 
         tcp_tqueue_ctrl_seg(conn, CTL_SYN | CTL_ACK /* XXX */);
+
+        tcp_segment_delete(seg);
 }
 
@@ -225 +244 @@
                 tcp_tqueue_ctrl_seg(conn, CTL_SYN | CTL_ACK /* XXX */);
         }
+
+        tcp_segment_delete(seg);
 }
 
@@ -288 +309 @@
 static cproc_t tcp_conn_seg_proc_ack_est(tcp_conn_t *conn, tcp_segment_t *seg)
 {
+        log_msg(LVL_DEBUG, "tcp_conn_seg_proc_ack_est(%p, %p)", conn, seg);
+
+        log_msg(LVL_DEBUG, "SEG.ACK=%u, SND.UNA=%u, SND.NXT=%u",
+            (unsigned)seg->ack, (unsigned)conn->snd_una,
+            (unsigned)conn->snd_nxt);
+
         if (!seq_no_ack_acceptable(conn, seg->ack)) {
+                log_msg(LVL_DEBUG, "ACK not acceptable.");
                 if (!seq_no_ack_duplicate(conn, seg->ack)) {
+                        log_msg(LVL_WARN, "Not acceptable, not duplicate. "
+                            "Send ACK and drop.");
                         /* Not acceptable, not duplicate. Send ACK and drop. */
                         tcp_tqueue_ctrl_seg(conn, CTL_ACK);
                         tcp_segment_delete(seg);
                         return cp_done;
+                } else {
+                        log_msg(LVL_DEBUG, "Ignoring duplicate ACK.");
                 }
         } else {
@@ -401 +433 @@
 }
 
+/** Process segment text. */
 static cproc_t tcp_conn_seg_proc_text(tcp_conn_t *conn, tcp_segment_t *seg)
 {
+        size_t text_size;
+        size_t xfer_size;
+
+        log_msg(LVL_DEBUG, "tcp_conn_seg_proc_text(%p, %p)", conn, seg);
+
         switch (conn->cstate) {
         case st_established:
@@ -422 +460 @@
         }
 
-        /* TODO Process segment text */
+        /*
+         * Process segment text
+         */
+        assert(seq_no_segment_ready(conn, seg));
+
+        /* Trim anything outside our receive window */
+        tcp_conn_trim_seg_to_wnd(conn, seg);
+
+        /* Determine how many bytes to copy */
+        text_size = tcp_segment_text_size(seg);
+        xfer_size = min(text_size, conn->rcv_buf_size - conn->rcv_buf_used);
+
+        /* Copy data to receive buffer */
+        tcp_segment_text_copy(seg, conn->rcv_buf, xfer_size);
+
+        /* Advance RCV.NXT */
+        conn->rcv_nxt += xfer_size;
+
+        /* Update receive window. XXX Not an efficient strategy. */
+        conn->rcv_wnd -= xfer_size;
+
+        /* XXX Signal user that some data arrived. */
+
+        /* Send ACK */
+        if (xfer_size > 0)
+                tcp_tqueue_ctrl_seg(conn, CTL_ACK);
+
+        /* Anything left in the segment? (text, FIN) */
+        if (xfer_size < seg->len) {
+                /*
+                 * Some text or control remains. Insert remainder back
+                 * into the incoming queue.
+                 */
+                tcp_conn_trim_seg_to_wnd(conn, seg);
+                tcp_iqueue_insert_seg(&conn->incoming, seg);
+
+                return cp_done;
+        }
+
         return cp_continue;
 }
@@ -472 +548 @@
         if (tcp_conn_seg_proc_fin(conn, seg) == cp_done)
                 return;
+
+        tcp_segment_delete(seg);
 }
 
@@ -498 +576 @@
 }
 
+void tcp_conn_trim_seg_to_wnd(tcp_conn_t *conn, tcp_segment_t *seg)
+{
+        uint32_t left, right;
+
+        seq_no_seg_trim_calc(conn, seg, &left, &right);
+        tcp_segment_trim(seg, left, right);
+}
+
 void tcp_unexpected_segment(tcp_sockpair_t *sp, tcp_segment_t *seg)
 {

uspace/srv/net/tl/tcp/conn.h

@@ -43 +43 @@
 extern tcp_conn_t *tcp_conn_find(tcp_sockpair_t *);
 extern void tcp_conn_segment_arrived(tcp_conn_t *, tcp_segment_t *);
+extern void tcp_conn_trim_seg_to_wnd(tcp_conn_t *, tcp_segment_t *);
 extern void tcp_unexpected_segment(tcp_sockpair_t *, tcp_segment_t *);
 extern void tcp_sockpair_flipped(tcp_sockpair_t *, tcp_sockpair_t *);

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

@@ -61 +61 @@
 
         /* XXX This will only work as long as we don't have any header options */
-        phdr->tcp_length = sizeof(tcp_header_t) + tcp_segment_data_len(seg);
+        phdr->tcp_length = sizeof(tcp_header_t) + tcp_segment_text_size(seg);
 }
 

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);

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

@@ -36 +36 @@
 #define SEGMENT_H
 
+#include <sys/types.h>
 #include "tcp_type.h"
 
@@ -42 +43 @@
 extern tcp_segment_t *tcp_segment_make_ctrl(tcp_control_t);
 extern tcp_segment_t *tcp_segment_make_rst(tcp_segment_t *);
-extern size_t tcp_segment_data_len(tcp_segment_t *);
+extern void tcp_segment_trim(tcp_segment_t *, uint32_t, uint32_t);
+extern void tcp_segment_text_copy(tcp_segment_t *, void *, size_t);
+extern size_t tcp_segment_text_size(tcp_segment_t *);
 
 

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

@@ -71 +71 @@
  *
  * ACK is duplicate if it refers to a sequence number that has
- * aleady been acked (SEG.ACK < SND.UNA).
+ * aleady been acked (SEG.ACK <= SND.UNA).
  */
 bool seq_no_ack_duplicate(tcp_conn_t *conn, uint32_t seg_ack)
@@ -81 +81 @@
          * equivalent of SEG.ACK < SND.UNA. Thus we do it
          * on a best-effort basis, based on the difference.
-         * [-2^31, 0) means less-than, [0, 2^31) means greater-than.
+         * [-2^31, 0) means less-than, 0 means equal, [0, 2^31)
+         * means greater-than. Less-than or equal means duplicate.
          */
         diff = seg_ack - conn->snd_una;
-        return (diff & (0x1 << 31)) != 0;
+        return diff == 0 || (diff & (0x1 << 31)) != 0;
 }
 
@@ -176 +177 @@
 }
 
+/** Calculate the amount of trim needed to fit segment in receive window. */
+extern void seq_no_seg_trim_calc(tcp_conn_t *conn, tcp_segment_t *seg,
+    uint32_t *left, uint32_t *right)
+{
+        assert(seq_no_segment_acceptable(conn, seg));
+
+        /*
+         * If RCV.NXT is between SEG.SEQ and RCV.NXT+RCV.WND, then
+         * left trim amount is positive
+         */
+        if (seq_no_lt_le(seg->seq, conn->rcv_nxt,
+            conn->rcv_nxt + conn->rcv_wnd)) {
+                *left = conn->rcv_nxt - seg->seq;
+        } else {
+                *left = 0;
+        }
+
+        /*
+         * If SEG.SEQ+SEG.LEN is between SEG.SEQ and RCV.NXT+RCV.WND,
+         * then right trim is zero.
+         */
+        if (seq_no_lt_le(seg->seq - 1, seg->seq + seg->len,
+            conn->rcv_nxt + conn->rcv_wnd)) {
+                *right = 0;
+        } else {
+                *right = (seg->seq + seg->len) -
+                    (conn->rcv_nxt + conn->rcv_wnd);
+        }
+}
+
 /**
  * @}

uspace/srv/net/tl/tcp/seq_no.h

@@ -46 +46 @@
 extern bool seq_no_segment_ready(tcp_conn_t *, tcp_segment_t *);
 extern bool seq_no_segment_acceptable(tcp_conn_t *, tcp_segment_t *);
+extern void seq_no_seg_trim_calc(tcp_conn_t *, tcp_segment_t *, uint32_t *,
+    uint32_t *);
 
 extern uint32_t seq_no_control_len(tcp_control_t);

uspace/srv/net/tl/tcp/tcp_type.h

@@ -109 +109 @@
         tcp_iqueue_t incoming;
 
+        /** Receive buffer */
+        uint8_t *rcv_buf;
+        /** Receive buffer size */
+        size_t rcv_buf_size;
+        size_t rcv_buf_used;
+
         /** Send unacknowledged */
         uint32_t snd_una;
@@ -153 +159 @@
         uint32_t up;
 
-        /** Segment data */
+        /** Segment data, may be moved when trimming segment */
         void *data;
+        /** Segment data, original pointer used to free data */
+        void *dfptr;
 } tcp_segment_t;