Diff: tcp/tcb.c

Revision:

61:aad055f1b0d1

Parent:

57:e0fb648acf48

Child:

65:37acccf2752f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tcp/tcb.c	Thu Jan 11 17:38:21 2018 +0000
@@ -0,0 +1,75 @@
+#include <stdint.h>
+
+#include   "log.h"
+#include   "tcp.h"
+#include   "tcb.h"
+#include "clock.h"
+
+#define TCB_COUNT 10
+
+#define TIMEOUT_SYN_RECEIVED 2
+#define TIMEOUT_ESTABLISHED 20
+#define TIMEOUT_CLOSING      2
+
+struct tcb tcbs[TCB_COUNT];
+
+uint32_t TcbGetIsn()
+{
+    static uint32_t isn = 0;
+    isn += 100000; //Gives each tcb 100,000 packets and won't repeat before 42,940 tcbs.
+    return isn;
+}
+struct tcb* TcbGetExisting(uint16_t port)
+{
+    for (int i = 0; i < TCB_COUNT; i++)
+    {
+        struct tcb* pTcb = tcbs + i;
+        if (pTcb->state != TCB_EMPTY && pTcb->port == port) return pTcb;
+    }
+    return NULL;
+}
+struct tcb* TcbGetEmpty()
+{
+    for (int i = 0; i < TCB_COUNT; i++)
+    {
+        struct tcb* pTcb = tcbs + i;
+        if (pTcb->state == TCB_EMPTY) return pTcb;
+    }
+    return NULL;
+}
+
+uint32_t TcbElapsed = 0;
+static void reap()
+{
+    static struct tcb* pTcb = tcbs;
+    
+    if (pTcb->state == TCB_EMPTY) return;
+    
+    uint32_t limit;
+    switch (pTcb->state)
+    {
+        case TCB_SYN_RECEIVED: limit = TIMEOUT_SYN_RECEIVED; break;
+        case TCB_ESTABLISHED:  limit = TIMEOUT_ESTABLISHED;  break;
+        case TCB_FIN_WAIT:     limit = TIMEOUT_CLOSING;      break;
+        case TCB_ACK_WAIT:     limit = TIMEOUT_CLOSING;      break;
+    }
+    
+    if (TcbElapsed - pTcb->elapsed > limit)
+    {
+        if (TcpTrace) LogTimeF("Reaping TCB %d port %d\r\n", pTcb - tcbs, pTcb->port);
+        pTcb->state = TCB_EMPTY;
+    }
+    
+    pTcb++;
+    if (pTcb >= tcbs + TCB_COUNT) pTcb = tcbs;
+}
+
+void TcbMain()
+{
+    if (ClockTicked) TcbElapsed++;
+    reap();
+}
+void TcbInit()
+{
+    for (int i = 0; i < TCB_COUNT; i++) tcbs[i].state = TCB_EMPTY;
+}