From: Alan Cox <alan@linux.intel.com>
Date: Fri, 3 Nov 2017 23:43:34 +0000 (+0000)
Subject: netd: first cut at a slip driver
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=6f7a44eab52c92f9dd1739baae106546145655c5;p=FUZIX.git

netd: first cut at a slip driver
---

diff --git a/Applications/netd/slip.c b/Applications/netd/slip.c
new file mode 100644
index 00000000..ed8b425c
--- /dev/null
+++ b/Applications/netd/slip.c
@@ -0,0 +1,157 @@
+/*
+ * 	SLIP interface. Really we need select() support for this or to ruute
+ *	slip via the kernel. TODO
+ */
+  
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <termios.h>
+
+#include "device.h"
+
+static int fd;  /* fd of the tty */
+
+static char ibuf[297];
+static char *iptr;
+
+#define SLIP_END		0xC0
+#define SLIP_ESC		0xDB
+#define ESC_END			0xDC
+#define ESC_ESC			0xDD
+
+static void slip_outbuf(uint8_t c)
+{
+    /* FIXME: buffer.. ? */
+    write(fd, &c, 1);
+}
+
+static void slip_flush(void)
+{
+}
+
+static void slip_out(uint8_t c)
+{
+    if (c == SLIP_ESC) {
+        slip_outbuf(SLIP_ESC);
+        slip_outbuf(ESC_ESC);
+    } else if (c == SLIP_END) {
+        slip_outbuf(SLIP_ESC);
+        slip_outbuf(ESC_END);
+    } else
+        slip_outbuf(c);
+}
+
+static void slip_begin(void)
+{
+    /* Should send an end mark if idle for a bit */
+}
+
+static void slip_end(void)
+{
+    slip_outbuf(SLIP_END);
+    slip_flush();
+}
+
+static void badpacket(void)
+{
+    iptr = ibuf;
+    fprintf(stderr, "overlong frame\n");
+}
+
+/* returns number of byte in next packet, 0 = nothing waiting */
+static int slip_poll( void )
+{
+    static uint8_t esc = 0;
+    uint8_t c;
+
+    if (read(fd, &c, 1) < 1 )
+        return 0;
+
+    /* If we saw an escape then process the escapes */
+    if (esc) {
+        esc = 0;
+        if (c == ESC_END)
+            *iptr++ = SLIP_END;
+        else if (c == ESC_ESC)
+            *iptr++ = SLIP_ESC;
+        else {
+            badpacket();
+            return 0;
+        }
+    } else {
+        /* An escape begins */
+        if (c == SLIP_ESC) {
+            esc = 1;
+            return 0;
+        }
+        /* End of frame */
+        if (c == SLIP_END) { 
+            int len = iptr - ibuf;
+            return len;
+        }
+        /* Queue the byte */
+        *iptr++ = c;
+    }
+    if (iptr == ibuf + 296)
+        badpacket();
+    return 0;
+}
+
+
+/* receive packet to a buffer */
+static int slip_recv( unsigned char *b, int len )
+{
+    /* Mark it as IP */
+    b[12] = 0x08;
+    b[13] = 0x00;
+    memcpy(b+14, ibuf, len);
+    iptr = ibuf;
+}
+
+/* send packet to net device */
+int device_send( char *sbuf, int len )
+{
+    sbuf += 14	/* Don't send a mac header */
+    slip_begin();
+    while(len--)
+        slip_out(*sbuf++);
+    slip_end();
+    return 0;
+}
+
+int device_read( char *buf, int len )
+{
+    if (slip_poll() == 0)
+        return 0;
+    return slip_recv(buf, len);
+}
+
+static struct termios t;
+/* initialize network device */
+int device_init(void)
+{
+    /* FIXME: don't hard code */
+    fd=open( "/dev/tty3", O_RDWR);
+    if( fd < 0  || tcgetattr(fd, &t) < 0) {
+        perror("/dev/tty3");
+	return -1;
+    }
+    t.c_iflag  = IGNBRK;
+    t.c_oflag = 0;
+    t.c_cflag &= ~(CSIZE|PARENB|HUPCL);
+    t.c_cflag |= CREAD|CS8;
+    t.c_lflag &= ~(ISIG|ICANON|ECHO|ECHOE|ECHOK);
+    t.c_cc[VMIN] = 0;
+    t.c_cc[VTIME] = 3;	/* 0.3 seconds */
+
+    if (tcsetattr(fd, 0, &t) < 0) {
+        perror("/dev/tty3");
+        return -1;
+    }
+    return 0;
+}
+
+int has_arp = 0;