Add PLIP network device

src/include/86box/lpt.h

@@ -1,3 +1,6 @@
+#ifndef EMU_LPT_H
+# define EMU_LPT_H
+
 typedef struct
 {
     const char *name;
@@ -58,3 +61,5 @@ extern const lpt_device_t lpt_dac_device;
 extern const lpt_device_t lpt_dac_stereo_device;
 
 extern const lpt_device_t dss_device;
+
+#endif /*EMU_LPT_H*/

src/include/86box/net_plip.h

@@ -0,0 +1,24 @@
+/*
+ * 86Box	A hypervisor and IBM PC system emulator that specializes in
+ *		running old operating systems and software designed for IBM
+ *		PC systems and compatibles from 1981 through fairly recent
+ *		system designs based on the PCI bus.
+ *
+ *		This file is part of the 86Box distribution.
+ *
+ *		Definitions for the PLIP parallel port network device.
+ *
+ *
+ *
+ * Author:	RichardG, <richardg867@gmail.com>
+ *		Copyright 2020 RichardG.
+ */
+#ifndef NET_PLIP_H
+# define NET_PLIP_H
+# include <86box/device.h>
+# include <86box/lpt.h>
+
+extern const lpt_device_t lpt_plip_device;
+extern const device_t plip_device;
+
+#endif	/*NET_PLIP_H*/

src/include/86box/network.h

@@ -101,6 +101,7 @@ extern "C" {
 /* Global variables. */
 extern int	nic_do_log;				/* config */
 extern int      network_ndev;
+extern int	network_rx_pause;
 extern netdev_t network_devs[32];
 
 

src/lpt.c

@@ -11,6 +11,7 @@
 #include <86box/pic.h>
 #include <86box/sound.h>
 #include <86box/prt_devs.h>
+#include <86box/net_plip.h>
 
 
 lpt_port_t	lpt_ports[3];
@@ -30,6 +31,7 @@ static const struct
 	{"Generic Text Printer",	 "text_prt",       &lpt_prt_text_device},
 	{"Generic ESC/P Dot-Matrix",     "dot_matrix",     &lpt_prt_escp_device},
 	{"Generic PostScript Printer",   "postscript",     &lpt_prt_ps_device},
+	{"PLIP Network",		 "plip",           &lpt_plip_device},
         {"", "", NULL}
 };
 
@@ -140,7 +142,7 @@ lpt_read(uint16_t port, void *priv)
 
 	case 1:
 		if (dev->dt && dev->dt->read_status)
-			ret = dev->dt->read_status(dev->priv) | 0x0f;
+			ret = dev->dt->read_status(dev->priv);
 		else
 			ret = 0xdf;
 		break;

src/network/net_plip.c

@@ -0,0 +1,507 @@
+/*
+ * 86Box	A hypervisor and IBM PC system emulator that specializes in
+ *		running old operating systems and software designed for IBM
+ *		PC systems and compatibles from 1981 through fairly recent
+ *		system designs based on the PCI bus.
+ *
+ *		This file is part of the 86Box distribution.
+ *
+ *		Emulation of a PLIP parallel port network device.
+ *
+ *		Tested against the Linux plip.c driver and the DOS plip.com
+ *		packet driver. PLIP is not particularly fast, as it's a 4-bit
+ *		half-duplex protocol operating over SPP.
+ *
+ *
+ *
+ * Author:	RichardG, <richardg867@gmail.com>
+ *		Copyright 2020 RichardG.
+ */
+#include <inttypes.h>
+#include <memory.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#define HAVE_STDARG_H
+#include <86box/86box.h>
+#include <86box/language.h>
+#include <86box/lpt.h>
+#include <86box/timer.h>
+#include <86box/pit.h>
+#include <86box/device.h>
+#include <86box/network.h>
+#include <86box/net_plip.h>
+
+
+enum {
+    PLIP_START = 0x00,
+    PLIP_TX_LEN_LSB_LOW = 0x10,
+    PLIP_TX_LEN_LSB_HIGH,
+    PLIP_TX_LEN_MSB_LOW,
+    PLIP_TX_LEN_MSB_HIGH,
+    PLIP_TX_DATA_LOW,
+    PLIP_TX_DATA_HIGH,
+    PLIP_TX_CHECKSUM_LOW,
+    PLIP_TX_CHECKSUM_HIGH,
+    PLIP_RX_LEN_LSB_LOW = 0x20,
+    PLIP_RX_LEN_LSB_HIGH,
+    PLIP_RX_LEN_MSB_LOW,
+    PLIP_RX_LEN_MSB_HIGH,
+    PLIP_RX_DATA_LOW,
+    PLIP_RX_DATA_HIGH,
+    PLIP_RX_CHECKSUM_LOW,
+    PLIP_RX_CHECKSUM_HIGH,
+    PLIP_END = 0x40
+};
+
+typedef struct
+{
+    uint8_t	mac[6];
+
+    void	*lpt;
+    pc_timer_t	rx_timer;
+    pc_timer_t	timeout_timer;
+    uint8_t	status, ctrl;
+
+    uint8_t	state, ack, tx_checksum, tx_checksum_calc, *tx_pkt;
+    uint16_t	tx_len, tx_ptr;
+
+    uint8_t	*rx_pkt, rx_checksum, rx_return_state;
+    uint16_t	rx_len, rx_ptr;
+} plip_t;
+
+
+static void	plip_receive_packet(plip_t *dev);
+
+plip_t	*instance;
+
+
+#ifdef ENABLE_PLIP_LOG
+int plip_do_log = ENABLE_PLIP_LOG;
+
+static void
+plip_log(uint8_t lvl, const char *fmt, ...)
+{
+    va_list ap;
+
+    if (plip_do_log >= lvl) {
+	va_start(ap, fmt);
+	pclog_ex(fmt, ap);
+	va_end(ap);
+    }
+}
+#else
+#define plip_log(lvl, fmt, ...)
+#endif
+
+
+static void
+timeout_timer(void *priv)
+{
+    plip_t *dev = (plip_t *) priv;
+
+    plip_log(1, "PLIP: timeout at state %d status %02X\n", dev->state, dev->status);
+
+    /* Throw everything out the window. */
+    dev->state = PLIP_START;
+    dev->status = 0x80;
+
+    if (dev->tx_pkt) {
+	free(dev->tx_pkt);
+	dev->tx_pkt = NULL;
+    }
+    if (dev->rx_pkt) {
+	free(dev->rx_pkt);
+	dev->rx_pkt = NULL;
+    }
+
+    timer_disable(&dev->timeout_timer);
+}
+
+
+static void
+plip_write_data(uint8_t val, void *priv)
+{
+    plip_t *dev = (plip_t *) priv;
+
+    plip_log(3, "PLIP: write_data(%02X)\n", val);
+
+    switch (dev->state) {
+	case PLIP_START:
+		if (val == 0x08) { /* D3/ACK wakes us up */
+			plip_log(2, "PLIP: ACK wakeup\n");
+			dev->state = PLIP_TX_LEN_LSB_LOW;
+			dev->status = 0x08;
+			break;
+		}
+		return;
+
+	case PLIP_TX_LEN_LSB_LOW:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		dev->tx_len = val & 0xf;
+		plip_log(2, "PLIP: tx_len = %04X (1/4)\n", dev->tx_len);
+		dev->state = PLIP_TX_LEN_LSB_HIGH;
+		dev->status &= ~0x88;
+		break;
+
+	case PLIP_TX_LEN_LSB_HIGH:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		dev->tx_len |= (val & 0xf) << 4;
+		plip_log(2, "PLIP: tx_len = %04X (2/4)\n", dev->tx_len);
+		dev->state = PLIP_TX_LEN_MSB_LOW;
+		dev->status |= 0x80;
+		break;
+
+	case PLIP_TX_LEN_MSB_LOW:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		dev->tx_len |= (val & 0xf) << 8;
+		plip_log(2, "PLIP: tx_len = %04X (3/4)\n", dev->tx_len);
+		dev->state = PLIP_TX_LEN_MSB_HIGH;
+		dev->status &= ~0x80;
+		break;
+
+	case PLIP_TX_LEN_MSB_HIGH:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		dev->tx_len |= (val & 0xf) << 12;
+		plip_log(2, "PLIP: tx_len = %04X (4/4)\n", dev->tx_len);
+
+		/* We have the length, allocate a packet. */
+		if (!(dev->tx_pkt = malloc(dev->tx_len))) /* unlikely */
+			fatal("PLIP: unable to allocate tx_pkt\n");
+		dev->tx_ptr = 0;
+		dev->tx_checksum_calc = 0;
+
+		dev->state = PLIP_TX_DATA_LOW;
+		dev->status |= 0x80;
+		break;
+
+	case PLIP_TX_DATA_LOW:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		dev->tx_pkt[dev->tx_ptr] = val & 0x0f;
+		plip_log(2, "PLIP: tx_pkt[%d] = %02X (1/2)\n", dev->tx_ptr, dev->tx_pkt[dev->tx_ptr]);
+		dev->state = PLIP_TX_DATA_HIGH;
+		dev->status &= ~0x80;
+		break;
+
+	case PLIP_TX_DATA_HIGH:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		dev->tx_pkt[dev->tx_ptr] |= (val & 0x0f) << 4;
+		plip_log(2, "PLIP: tx_pkt[%d] = %02X (2/2)\n", dev->tx_ptr, dev->tx_pkt[dev->tx_ptr]);
+		dev->tx_checksum_calc += dev->tx_pkt[dev->tx_ptr++];
+
+		/* Are we done yet? */
+		if (dev->tx_ptr < dev->tx_len) /* no, receive another byte */
+			dev->state = PLIP_TX_DATA_LOW;
+		else /* yes, move on to checksum */
+			dev->state = PLIP_TX_CHECKSUM_LOW;
+		dev->status |= 0x80;
+		break;
+
+	case PLIP_TX_CHECKSUM_LOW:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		dev->tx_checksum = val & 0x0f;
+		plip_log(2, "PLIP: tx_checksum = %02X (1/2)\n", dev->tx_checksum);
+		dev->state = PLIP_TX_CHECKSUM_HIGH;
+		dev->status &= ~0x80;
+		break;
+
+	case PLIP_TX_CHECKSUM_HIGH:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		dev->tx_checksum |= (val & 0x0f) << 4;
+		plip_log(2, "PLIP: tx_checksum = %02X (2/2)\n", dev->tx_checksum);
+
+		/* Verify checksum. */
+		if (dev->tx_checksum_calc == dev->tx_checksum) {
+			/* Make sure we know the other end's MAC address. */
+			memcpy(dev->mac, dev->tx_pkt + 6, 6);
+
+			/* Transmit packet. */
+			plip_log(2, "PLIP: transmitting %d-byte packet\n", dev->tx_len);
+			network_tx(dev->tx_pkt, dev->tx_len);
+		} else {
+			plip_log(1, "PLIP: checksum error: expected %02X, got %02X\n", dev->tx_checksum_calc, dev->tx_checksum);
+		}
+
+		/* We're done with this packet. */
+		free(dev->tx_pkt);
+		dev->tx_pkt = NULL;
+		dev->tx_len = 0;
+
+		dev->state = PLIP_END;
+		dev->status |= 0x80;
+		break;
+
+	case PLIP_RX_LEN_LSB_LOW:
+		if (!(val & 0x01))
+			return; /* D3/ACK not high yet */
+		plip_log(2, "PLIP: rx_len = %04X (1/4)\n", dev->rx_len);
+		dev->status = (dev->rx_len & 0x0f) << 3;
+		dev->state = PLIP_RX_LEN_LSB_HIGH;
+		break;
+
+	case PLIP_RX_LEN_LSB_HIGH:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		plip_log(2, "PLIP: rx_len = %04X (2/4)\n", dev->rx_len);
+		dev->status = ((dev->rx_len >> 4) & 0x0f) << 3;
+		dev->status |= 0x80;
+		dev->state = PLIP_RX_LEN_MSB_LOW;
+		break;
+
+	case PLIP_RX_LEN_MSB_LOW:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		plip_log(2, "PLIP: rx_len = %04X (3/4)\n", dev->rx_len);
+		dev->status = ((dev->rx_len >> 8) & 0x0f) << 3;
+		dev->state = PLIP_RX_LEN_MSB_HIGH;
+		break;
+
+	case PLIP_RX_LEN_MSB_HIGH:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		plip_log(2, "PLIP: rx_len = %04X (4/4)\n", dev->rx_len);
+		dev->status = ((dev->rx_len >> 12) & 0x0f) << 3;
+		dev->status |= 0x80;
+
+		dev->rx_ptr = 0;
+		dev->rx_checksum = 0;
+		dev->state = PLIP_RX_DATA_LOW;
+		break;
+
+	case PLIP_RX_DATA_LOW:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		plip_log(2, "PLIP: rx_pkt[%d] = %02X (1/2)\n", dev->rx_ptr, dev->rx_pkt[dev->rx_ptr]);
+		dev->status = (dev->rx_pkt[dev->rx_ptr] & 0x0f) << 3;
+		dev->state = PLIP_RX_DATA_HIGH;
+		break;
+
+	case PLIP_RX_DATA_HIGH:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		plip_log(2, "PLIP: rx_pkt[%d] = %02X (2/2)\n", dev->rx_ptr, dev->rx_pkt[dev->rx_ptr]);
+		dev->status = ((dev->rx_pkt[dev->rx_ptr] >> 4) & 0x0f) << 3;
+		dev->status |= 0x80;
+		dev->rx_checksum += dev->rx_pkt[dev->rx_ptr++];
+
+		/* Are we done yet? */
+		if (dev->rx_ptr < dev->rx_len) /* no, send another byte */
+			dev->state = PLIP_RX_DATA_LOW;
+		else /* yes, move on to checksum */
+			dev->state = PLIP_RX_CHECKSUM_LOW;
+		break;
+
+	case PLIP_RX_CHECKSUM_LOW:
+		if (val & 0x10)
+			return; /* D4/BUSY not low yet */
+		plip_log(2, "PLIP: rx_checksum = %02X (1/2)\n", dev->rx_checksum);
+		dev->status = (dev->rx_checksum & 0x0f) << 3;
+		dev->state = PLIP_RX_CHECKSUM_HIGH;
+		break;
+
+	case PLIP_RX_CHECKSUM_HIGH:
+		if (!(val & 0x10))
+			return; /* D4/BUSY not high yet */
+		plip_log(2, "PLIP: rx_checksum = %02X (2/2)\n", dev->rx_checksum);
+		dev->status = ((dev->rx_checksum >> 4) & 0x0f) << 3;
+		dev->status |= 0x80;
+
+		/* We're done with this packet. */
+		free(dev->rx_pkt);
+		dev->rx_pkt = NULL;
+		dev->rx_len = 0;
+
+		dev->state = PLIP_END;
+		break;
+
+	case PLIP_END:
+		if (val == 0x00) { /* written after TX or RX is done */
+			plip_log(2, "PLIP: end\n");
+			dev->status = 0x80;
+			dev->state = PLIP_START;
+
+			timer_set_delay_u64(&dev->rx_timer, ISACONST); /* for DOS */
+		}
+
+		/* Disengage timeout timer. */
+		timer_disable(&dev->timeout_timer);
+		return;
+    }
+
+    /* Engage timeout timer unless otherwise specified. */
+    timer_set_delay_u64(&dev->timeout_timer, 1000000 * TIMER_USEC);
+}
+
+
+static void
+plip_write_ctrl(uint8_t val, void *priv)
+{
+    plip_t *dev = (plip_t *) priv;
+
+    plip_log(3, "PLIP: write_ctrl(%02X)\n", val);
+
+    dev->ctrl = val;
+
+    if (val & 0x10) /* for Linux */
+	timer_set_delay_u64(&dev->rx_timer, ISACONST);
+}
+
+
+static uint8_t
+plip_read_status(void *priv)
+{
+    plip_t *dev = (plip_t *) priv;
+
+    plip_log(3, "PLIP: read_status() = %02X\n", dev->status);
+
+    return dev->status;
+}
+
+
+static void
+plip_receive_packet(plip_t *dev)
+{
+    /* At least the Linux driver supports being interrupted
+       in the PLIP_TX_LEN_LSB_LOW state, but let's be safe. */
+    if (dev->state > PLIP_START) {
+	plip_log(3, "PLIP: cannot receive, operation already in progress\n");
+	return;
+    }
+
+    if (!dev->rx_pkt || !dev->rx_len) { /* unpause RX queue if there's no packet to receive */
+	network_rx_pause = 0;
+	return;
+    }
+
+    if (!(dev->ctrl & 0x10)) { /* checking this is essential to avoid collisions */
+	plip_log(3, "PLIP: cannot receive, interrupts are off\n");
+	return;
+    }
+
+    plip_log(2, "PLIP: receiving %d-byte packet\n", dev->rx_len);
+
+    /* Set up to receive a packet. */
+    dev->status = 0xc7; /* DOS expects exactly 0xc7, while Linux masks the 7 off */
+    dev->state = PLIP_RX_LEN_LSB_LOW;
+
+    /* Engage timeout timer. */
+    timer_set_delay_u64(&dev->timeout_timer, 1000000 * TIMER_USEC);
+
+    /* Wake the other end up. */
+    lpt_irq(dev->lpt, 1);
+}
+
+
+/* This timer defers a call to plip_receive_packet to
+   the next ISA clock, in order to avoid IRQ weirdness. */
+static void
+rx_timer(void *priv)
+{
+    plip_t *dev = (plip_t *) priv;
+
+    plip_receive_packet(dev);
+
+    timer_disable(&dev->rx_timer);
+}
+
+
+static void
+plip_rx(void *priv, uint8_t *buf, int io_len)
+{
+    plip_t *dev = (plip_t *) priv;
+
+    plip_log(2, "PLIP: incoming %d-byte packet\n", io_len);
+
+    if (dev->rx_pkt) { /* shouldn't really happen with the RX queue paused */
+	plip_log(3, "PLIP: already have a packet to receive");
+	return;
+    }
+
+    if (!(dev->rx_pkt = malloc(io_len))) /* unlikely */
+	fatal("PLIP: unable to allocate rx_pkt\n");
+
+    network_rx_pause = 1; /* make sure we don't get any more packets while processing this one */
+
+    /* Copy this packet to our buffer. */
+    dev->rx_len = io_len;
+    memcpy(dev->rx_pkt, buf, dev->rx_len);
+
+    /* Dispatch this packet immediately if we're doing nothing. */
+    plip_receive_packet(dev);
+}
+
+
+static void *
+plip_lpt_init(void *lpt)
+{
+    plip_t *dev = (plip_t *) malloc(sizeof(plip_t));
+    memset(dev, 0, sizeof(plip_t));
+
+    plip_log(1, "PLIP: lpt_init()\n");
+
+    dev->lpt = lpt;
+    memset(dev->mac, 0xfc, 6); /* static MAC used by Linux; just a placeholder */
+
+    dev->status = 0x80;
+
+    timer_add(&dev->rx_timer, rx_timer, dev, 0);
+    timer_add(&dev->timeout_timer, timeout_timer, dev, 0);
+
+    instance = dev;
+
+    return dev;
+}
+
+
+static void *
+plip_net_init(const device_t *info)
+{
+    plip_log(1, "PLIP: net_init()");
+
+    if (!instance) {
+	plip_log(1, " (not attached to LPT)\n");
+	return NULL;
+    }
+
+    plip_log(1, " (attached to LPT)\n");
+    network_attach(instance, instance->mac, plip_rx, NULL, NULL);
+
+    return instance;
+}
+
+
+static void
+plip_close(void *priv)
+{
+    free(priv);
+}
+
+
+const lpt_device_t lpt_plip_device = {
+    .name = "Parallel Line Internet Protocol (LPT)",
+    .init = plip_lpt_init,
+    .close = plip_close,
+    .write_data = plip_write_data,
+    .write_ctrl = plip_write_ctrl,
+    .read_data = NULL,
+    .read_status = plip_read_status,
+    .read_ctrl = NULL
+};
+
+const device_t plip_device =
+{
+        "Parallel Line Internet Protocol (Network)",
+        0, 0,
+        plip_net_init, NULL,
+	NULL, NULL, NULL, NULL
+};

src/win/Makefile.mingw

@@ -721,7 +721,8 @@ NETOBJ		:= network.o \
 		     tcp_output.o tcp_subr.o tcp_timer.o udp.o util.o version.o \
 		    net_dp8390.o \
 		    net_3c503.o net_ne2000.o \
-		    net_pcnet.o net_wd8003.o
+		    net_pcnet.o net_wd8003.o \
+		    net_plip.o
 
 PRINTOBJ	:= png.o prt_cpmap.o \
 		    prt_escp.o prt_text.o prt_ps.o