src/Unix/ether_unix.cpp

/*
 *  ether_unix.cpp - Ethernet device driver, Unix specific stuff (Linux and FreeBSD)
 *
 *  Basilisk II (C) 1997-2002 Christian Bauer
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "sysdeps.h"

#include <sys/ioctl.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <pthread.h>
#include <semaphore.h>
#include <errno.h>
#include <stdio.h>
#include <map>

#if defined(__FreeBSD__) || defined(sgi)
#include <net/if.h>
#endif

#include "cpu_emulation.h"
#include "main.h"
#include "macos_util.h"
#include "prefs.h"
#include "user_strings.h"
#include "ether.h"
#include "ether_defs.h"

#ifndef NO_STD_NAMESPACE
using std::map;
#endif

#define DEBUG 0
#include "debug.h"

#define MONITOR 0


// Global variables
static int fd = -1;                                                     // fd of sheep_net device
static pthread_t ether_thread;                          // Packet reception thread
static pthread_attr_t ether_thread_attr;        // Packet reception thread attributes
static bool thread_active = false;                      // Flag: Packet reception thread installed
static sem_t int_ack;                                           // Interrupt acknowledge semaphore
static bool is_ethertap;                                        // Flag: Ethernet device is ethertap
static bool udp_tunnel;                                         // Flag: UDP tunnelling active, fd is the socket descriptor

// Attached network protocols, maps protocol type to MacOS handler address
static map<uint16, uint32> net_protocols;

// Prototypes
static void *receive_func(void *arg);


/*
 *  Start packet reception thread
 */

static bool start_thread(void)
{
        if (sem_init(&int_ack, 0, 0) < 0) {
                printf("WARNING: Cannot init semaphore");
                return false;
        }

        pthread_attr_init(&ether_thread_attr);
#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
        if (geteuid() == 0) {
                pthread_attr_setinheritsched(&ether_thread_attr, PTHREAD_EXPLICIT_SCHED);
                pthread_attr_setschedpolicy(&ether_thread_attr, SCHED_FIFO);
                struct sched_param fifo_param;
                fifo_param.sched_priority = (sched_get_priority_min(SCHED_FIFO) + sched_get_priority_max(SCHED_FIFO)) / 2 + 1;
                pthread_attr_setschedparam(&ether_thread_attr, &fifo_param);
        }
#endif

        thread_active = (pthread_create(&ether_thread, &ether_thread_attr, receive_func, NULL) == 0);
        if (!thread_active) {
                printf("WARNING: Cannot start Ethernet thread");
                return false;
        }

        return true;
}


/*
 *  Stop packet reception thread
 */

static void stop_thread(void)
{
        if (thread_active) {
                pthread_cancel(ether_thread);
                pthread_join(ether_thread, NULL);
                sem_destroy(&int_ack);
                thread_active = false;
        }
}


/*
 *  Initialization
 */

bool ether_init(void)
{
        int nonblock = 1;
        char str[256];

        // Do nothing if no Ethernet device specified
        const char *name = PrefsFindString("ether");
        if (name == NULL)
                return false;

        // Is it Ethertap?
        is_ethertap = (strncmp(name, "tap", 3) == 0);

        // Open sheep_net or ethertap device
        char dev_name[16];
        if (is_ethertap)
                sprintf(dev_name, "/dev/%s", name);
        else
                strcpy(dev_name, "/dev/sheep_net");
        fd = open(dev_name, O_RDWR);
        if (fd < 0) {
                sprintf(str, GetString(STR_NO_SHEEP_NET_DRIVER_WARN), dev_name, strerror(errno));
                WarningAlert(str);
                goto open_error;
        }

#if defined(__linux__)
        // Attach sheep_net to selected Ethernet card
        if (!is_ethertap && ioctl(fd, SIOCSIFLINK, name) < 0) {
                sprintf(str, GetString(STR_SHEEP_NET_ATTACH_WARN), strerror(errno));
                WarningAlert(str);
                goto open_error;
        }
#endif

        // Set nonblocking I/O
        ioctl(fd, FIONBIO, &nonblock);

        // Get Ethernet address
        if (is_ethertap) {
                pid_t p = getpid();     // If configured for multicast, ethertap requires that the lower 32 bit of the Ethernet address are our PID
                ether_addr[0] = 0xfe;
                ether_addr[1] = 0xfd;
                ether_addr[2] = p >> 24;
                ether_addr[3] = p >> 16;
                ether_addr[4] = p >> 8;
                ether_addr[5] = p;
        } else
                ioctl(fd, SIOCGIFADDR, ether_addr);
        D(bug("Ethernet address %02x %02x %02x %02x %02x %02x\n", ether_addr[0], ether_addr[1], ether_addr[2], ether_addr[3], ether_addr[4], ether_addr[5]));

        // Start packet reception thread
        if (!start_thread())
                goto open_error;

        // Everything OK
        return true;

open_error:
        stop_thread();

        if (fd > 0) {
                close(fd);
                fd = -1;
        }
        return false;
}


/*
 *  Deinitialization
 */

void ether_exit(void)
{
        // Stop reception thread
        if (thread_active) {
                pthread_cancel(ether_thread);
                pthread_join(ether_thread, NULL);
                sem_destroy(&int_ack);
                thread_active = false;
        }

        // Close sheep_net device
        if (fd > 0)
                close(fd);
}


/*
 *  Reset
 */

void ether_reset(void)
{
        net_protocols.clear();
}


/*
 *  Add multicast address
 */

int16 ether_add_multicast(uint32 pb)
{
        if (ioctl(fd, SIOCADDMULTI, Mac2HostAddr(pb + eMultiAddr)) < 0) {
                D(bug("WARNING: Couldn't enable multicast address\n"));
                if (is_ethertap)
                        return noErr;
                else
                        return eMultiErr;
        } else
                return noErr;
}


/*
 *  Delete multicast address
 */

int16 ether_del_multicast(uint32 pb)
{
        if (ioctl(fd, SIOCDELMULTI, Mac2HostAddr(pb + eMultiAddr)) < 0) {
                D(bug("WARNING: Couldn't disable multicast address\n"));
                return eMultiErr;
        } else
                return noErr;
}


/*
 *  Attach protocol handler
 */

int16 ether_attach_ph(uint16 type, uint32 handler)
{
        if (net_protocols.find(type) != net_protocols.end())
                return lapProtErr;
        net_protocols[type] = handler;
        return noErr;
}


/*
 *  Detach protocol handler
 */

int16 ether_detach_ph(uint16 type)
{
        if (net_protocols.erase(type) == 0)
                return lapProtErr;
        return noErr;
}


/*
 *  Transmit raw ethernet packet
 */

int16 ether_write(uint32 wds)
{
        // Copy packet to buffer
        uint8 packet[1516], *p = packet;
        int len = 0;
#if defined(__linux__)
        if (is_ethertap) {
                *p++ = 0;       // Linux ethertap discards the first 2 bytes
                *p++ = 0;
                len += 2;
        }
#endif
        len += ether_wds_to_buffer(wds, p);

#if MONITOR
        bug("Sending Ethernet packet:\n");
        for (int i=0; i<len; i++) {
                bug("%02x ", packet[i]);
        }
        bug("\n");
#endif

        // Transmit packet
        if (write(fd, packet, len) < 0) {
                D(bug("WARNING: Couldn't transmit packet\n"));
                return excessCollsns;
        } else
                return noErr;
}


/*
 *  Start UDP packet reception thread
 */

bool ether_start_udp_thread(int socket_fd)
{
        fd = socket_fd;
        udp_tunnel = true;
        return start_thread();
}


/*
 *  Stop UDP packet reception thread
 */

void ether_stop_udp_thread(void)
{
        stop_thread();
        fd = -1;
}


/*
 *  Packet reception thread
 */

static void *receive_func(void *arg)
{
        for (;;) {

                // Wait for packets to arrive
                struct pollfd pf = {fd, POLLIN, 0};
                int res = poll(&pf, 1, -1);
                if (res <= 0)
                        break;

                // Trigger Ethernet interrupt
                D(bug(" packet received, triggering Ethernet interrupt\n"));
                SetInterruptFlag(INTFLAG_ETHER);
                TriggerInterrupt();

                // Wait for interrupt acknowledge by EtherInterrupt()
                sem_wait(&int_ack);
        }
        return NULL;
}


/*
 *  Ethernet interrupt - activate deferred tasks to call IODone or protocol handlers
 */

void EtherInterrupt(void)
{
        D(bug("EtherIRQ\n"));

        // Call protocol handler for received packets
        uint8 packet[1516];
        ssize_t length;
        for (;;) {

                if (udp_tunnel) {

                        // Read packet from socket
                        struct sockaddr_in from;
                        socklen_t from_len = sizeof(from);
                        length = recvfrom(fd, packet, 1514, 0, (struct sockaddr *)&from, &from_len);
                        if (length < 14)
                                break;
                        ether_udp_read(packet, length, &from);

                } else {

                        // Read packet from sheep_net device
#if defined(__linux__)
                        length = read(fd, packet, is_ethertap ? 1516 : 1514);
#else
                        length = read(fd, packet, 1514);
#endif
                        if (length < 14)
                                break;

#if MONITOR
                        bug("Receiving Ethernet packet:\n");
                        for (int i=0; i<length; i++) {
                                bug("%02x ", packet[i]);
                        }
                        bug("\n");
#endif

                        // Pointer to packet data (Ethernet header)
                        uint8 *p = packet;
#if defined(__linux__)
                        if (is_ethertap) {
                                p += 2;                 // Linux ethertap has two random bytes before the packet
                                length -= 2;
                        }
#endif

                        // Get packet type
                        uint16 type = (p[12] << 8) | p[13];

                        // Look for protocol
                        uint16 search_type = (type <= 1500 ? 0 : type);
                        if (net_protocols.find(search_type) == net_protocols.end())
                                continue;
                        uint32 handler = net_protocols[search_type];

                        // No default handler
                        if (handler == 0)
                                continue;

                        // Copy header to RHA
                        Host2Mac_memcpy(ether_data + ed_RHA, p, 14);
                        D(bug(" header %08x%04x %08x%04x %04x\n", ReadMacInt32(ether_data + ed_RHA), ReadMacInt16(ether_data + ed_RHA + 4), ReadMacInt32(ether_data + ed_RHA + 6), ReadMacInt16(ether_data + ed_RHA + 10), ReadMacInt16(ether_data + ed_RHA + 12)));

                        // Call protocol handler
                        M68kRegisters r;
                        r.d[0] = type;                                                                  // Packet type
                        r.d[1] = length - 14;                                                   // Remaining packet length (without header, for ReadPacket)
                        r.a[0] = (uint32)p + 14;                                                // Pointer to packet (host address, for ReadPacket)
                        r.a[3] = ether_data + ed_RHA + 14;                              // Pointer behind header in RHA
                        r.a[4] = ether_data + ed_ReadPacket;                    // Pointer to ReadPacket/ReadRest routines
                        D(bug(" calling protocol handler %08x, type %08x, length %08x, data %08x, rha %08x, read_packet %08x\n", handler, r.d[0], r.d[1], r.a[0], r.a[3], r.a[4]));
                        Execute68k(handler, &r);
                }
        }

        // Acknowledge interrupt to reception thread
        D(bug(" EtherIRQ done\n"));
        sem_post(&int_ack);
}
Revision:	1.6
Committed:	2002-01-15T14:58:37Z (22 years, 10 months ago) by cebix
Branch:	MAIN
CVS Tags:	snapshot-15012002
Changes since 1.5:	+1 -1 lines
Log Message:	- documentation updates - 2001 -> 2002 - version 0.9 -> 1.0
#	Content
1	/*
2	* ether_unix.cpp - Ethernet device driver, Unix specific stuff (Linux and FreeBSD)
3	*
4	* Basilisk II (C) 1997-2002 Christian Bauer
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation; either version 2 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19	*/
20
21	#include "sysdeps.h"
22
23	#include <sys/ioctl.h>
24	#include <sys/poll.h>
25	#include <sys/socket.h>
26	#include <netinet/in.h>
27	#include <pthread.h>
28	#include <semaphore.h>
29	#include <errno.h>
30	#include <stdio.h>
31	#include <map>
32
33	#if defined(__FreeBSD__) \|\| defined(sgi)
34	#include <net/if.h>
35	#endif
36
37	#include "cpu_emulation.h"
38	#include "main.h"
39	#include "macos_util.h"
40	#include "prefs.h"
41	#include "user_strings.h"
42	#include "ether.h"
43	#include "ether_defs.h"
44
45	#ifndef NO_STD_NAMESPACE
46	using std::map;
47	#endif
48
49	#define DEBUG 0
50	#include "debug.h"
51
52	#define MONITOR 0
53
54
55	// Global variables
56	static int fd = -1; // fd of sheep_net device
57	static pthread_t ether_thread; // Packet reception thread
58	static pthread_attr_t ether_thread_attr; // Packet reception thread attributes
59	static bool thread_active = false; // Flag: Packet reception thread installed
60	static sem_t int_ack; // Interrupt acknowledge semaphore
61	static bool is_ethertap; // Flag: Ethernet device is ethertap
62	static bool udp_tunnel; // Flag: UDP tunnelling active, fd is the socket descriptor
63
64	// Attached network protocols, maps protocol type to MacOS handler address
65	static map<uint16, uint32> net_protocols;
66
67	// Prototypes
68	static void receive_func(void arg);
69
70
71	/*
72	* Start packet reception thread
73	*/
74
75	static bool start_thread(void)
76	{
77	if (sem_init(&int_ack, 0, 0) < 0) {
78	printf("WARNING: Cannot init semaphore");
79	return false;
80	}
81
82	pthread_attr_init(&ether_thread_attr);
83	#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
84	if (geteuid() == 0) {
85	pthread_attr_setinheritsched(&ether_thread_attr, PTHREAD_EXPLICIT_SCHED);
86	pthread_attr_setschedpolicy(&ether_thread_attr, SCHED_FIFO);
87	struct sched_param fifo_param;
88	fifo_param.sched_priority = (sched_get_priority_min(SCHED_FIFO) + sched_get_priority_max(SCHED_FIFO)) / 2 + 1;
89	pthread_attr_setschedparam(&ether_thread_attr, &fifo_param);
90	}
91	#endif
92
93	thread_active = (pthread_create(&ether_thread, &ether_thread_attr, receive_func, NULL) == 0);
94	if (!thread_active) {
95	printf("WARNING: Cannot start Ethernet thread");
96	return false;
97	}
98
99	return true;
100	}
101
102
103	/*
104	* Stop packet reception thread
105	*/
106
107	static void stop_thread(void)
108	{
109	if (thread_active) {
110	pthread_cancel(ether_thread);
111	pthread_join(ether_thread, NULL);
112	sem_destroy(&int_ack);
113	thread_active = false;
114	}
115	}
116
117
118	/*
119	* Initialization
120	*/
121
122	bool ether_init(void)
123	{
124	int nonblock = 1;
125	char str[256];
126
127	// Do nothing if no Ethernet device specified
128	const char *name = PrefsFindString("ether");
129	if (name == NULL)
130	return false;
131
132	// Is it Ethertap?
133	is_ethertap = (strncmp(name, "tap", 3) == 0);
134
135	// Open sheep_net or ethertap device
136	char dev_name[16];
137	if (is_ethertap)
138	sprintf(dev_name, "/dev/%s", name);
139	else
140	strcpy(dev_name, "/dev/sheep_net");
141	fd = open(dev_name, O_RDWR);
142	if (fd < 0) {
143	sprintf(str, GetString(STR_NO_SHEEP_NET_DRIVER_WARN), dev_name, strerror(errno));
144	WarningAlert(str);
145	goto open_error;
146	}
147
148	#if defined(__linux__)
149	// Attach sheep_net to selected Ethernet card
150	if (!is_ethertap && ioctl(fd, SIOCSIFLINK, name) < 0) {
151	sprintf(str, GetString(STR_SHEEP_NET_ATTACH_WARN), strerror(errno));
152	WarningAlert(str);
153	goto open_error;
154	}
155	#endif
156
157	// Set nonblocking I/O
158	ioctl(fd, FIONBIO, &nonblock);
159
160	// Get Ethernet address
161	if (is_ethertap) {
162	pid_t p = getpid(); // If configured for multicast, ethertap requires that the lower 32 bit of the Ethernet address are our PID
163	ether_addr[0] = 0xfe;
164	ether_addr[1] = 0xfd;
165	ether_addr[2] = p >> 24;
166	ether_addr[3] = p >> 16;
167	ether_addr[4] = p >> 8;
168	ether_addr[5] = p;
169	} else
170	ioctl(fd, SIOCGIFADDR, ether_addr);
171	D(bug("Ethernet address %02x %02x %02x %02x %02x %02x\n", ether_addr[0], ether_addr[1], ether_addr[2], ether_addr[3], ether_addr[4], ether_addr[5]));
172
173	// Start packet reception thread
174	if (!start_thread())
175	goto open_error;
176
177	// Everything OK
178	return true;
179
180	open_error:
181	stop_thread();
182
183	if (fd > 0) {
184	close(fd);
185	fd = -1;
186	}
187	return false;
188	}
189
190
191	/*
192	* Deinitialization
193	*/
194
195	void ether_exit(void)
196	{
197	// Stop reception thread
198	if (thread_active) {
199	pthread_cancel(ether_thread);
200	pthread_join(ether_thread, NULL);
201	sem_destroy(&int_ack);
202	thread_active = false;
203	}
204
205	// Close sheep_net device
206	if (fd > 0)
207	close(fd);
208	}
209
210
211	/*
212	* Reset
213	*/
214
215	void ether_reset(void)
216	{
217	net_protocols.clear();
218	}
219
220
221	/*
222	* Add multicast address
223	*/
224
225	int16 ether_add_multicast(uint32 pb)
226	{
227	if (ioctl(fd, SIOCADDMULTI, Mac2HostAddr(pb + eMultiAddr)) < 0) {
228	D(bug("WARNING: Couldn't enable multicast address\n"));
229	if (is_ethertap)
230	return noErr;
231	else
232	return eMultiErr;
233	} else
234	return noErr;
235	}
236
237
238	/*
239	* Delete multicast address
240	*/
241
242	int16 ether_del_multicast(uint32 pb)
243	{
244	if (ioctl(fd, SIOCDELMULTI, Mac2HostAddr(pb + eMultiAddr)) < 0) {
245	D(bug("WARNING: Couldn't disable multicast address\n"));
246	return eMultiErr;
247	} else
248	return noErr;
249	}
250
251
252	/*
253	* Attach protocol handler
254	*/
255
256	int16 ether_attach_ph(uint16 type, uint32 handler)
257	{
258	if (net_protocols.find(type) != net_protocols.end())
259	return lapProtErr;
260	net_protocols[type] = handler;
261	return noErr;
262	}
263
264
265	/*
266	* Detach protocol handler
267	*/
268
269	int16 ether_detach_ph(uint16 type)
270	{
271	if (net_protocols.erase(type) == 0)
272	return lapProtErr;
273	return noErr;
274	}
275
276
277	/*
278	* Transmit raw ethernet packet
279	*/
280
281	int16 ether_write(uint32 wds)
282	{
283	// Copy packet to buffer
284	uint8 packet[1516], *p = packet;
285	int len = 0;
286	#if defined(__linux__)
287	if (is_ethertap) {
288	*p++ = 0; // Linux ethertap discards the first 2 bytes
289	*p++ = 0;
290	len += 2;
291	}
292	#endif
293	len += ether_wds_to_buffer(wds, p);
294
295	#if MONITOR
296	bug("Sending Ethernet packet:\n");
297	for (int i=0; i<len; i++) {
298	bug("%02x ", packet[i]);
299	}
300	bug("\n");
301	#endif
302
303	// Transmit packet
304	if (write(fd, packet, len) < 0) {
305	D(bug("WARNING: Couldn't transmit packet\n"));
306	return excessCollsns;
307	} else
308	return noErr;
309	}
310
311
312	/*
313	* Start UDP packet reception thread
314	*/
315
316	bool ether_start_udp_thread(int socket_fd)
317	{
318	fd = socket_fd;
319	udp_tunnel = true;
320	return start_thread();
321	}
322
323
324	/*
325	* Stop UDP packet reception thread
326	*/
327
328	void ether_stop_udp_thread(void)
329	{
330	stop_thread();
331	fd = -1;
332	}
333
334
335	/*
336	* Packet reception thread
337	*/
338
339	static void receive_func(void arg)
340	{
341	for (;;) {
342
343	// Wait for packets to arrive
344	struct pollfd pf = {fd, POLLIN, 0};
345	int res = poll(&pf, 1, -1);
346	if (res <= 0)
347	break;
348
349	// Trigger Ethernet interrupt
350	D(bug(" packet received, triggering Ethernet interrupt\n"));
351	SetInterruptFlag(INTFLAG_ETHER);
352	TriggerInterrupt();
353
354	// Wait for interrupt acknowledge by EtherInterrupt()
355	sem_wait(&int_ack);
356	}
357	return NULL;
358	}
359
360
361	/*
362	* Ethernet interrupt - activate deferred tasks to call IODone or protocol handlers
363	*/
364
365	void EtherInterrupt(void)
366	{
367	D(bug("EtherIRQ\n"));
368
369	// Call protocol handler for received packets
370	uint8 packet[1516];
371	ssize_t length;
372	for (;;) {
373
374	if (udp_tunnel) {
375
376	// Read packet from socket
377	struct sockaddr_in from;
378	socklen_t from_len = sizeof(from);
379	length = recvfrom(fd, packet, 1514, 0, (struct sockaddr *)&from, &from_len);
380	if (length < 14)
381	break;
382	ether_udp_read(packet, length, &from);
383
384	} else {
385
386	// Read packet from sheep_net device
387	#if defined(__linux__)
388	length = read(fd, packet, is_ethertap ? 1516 : 1514);
389	#else
390	length = read(fd, packet, 1514);
391	#endif
392	if (length < 14)
393	break;
394
395	#if MONITOR
396	bug("Receiving Ethernet packet:\n");
397	for (int i=0; i<length; i++) {
398	bug("%02x ", packet[i]);
399	}
400	bug("\n");
401	#endif
402
403	// Pointer to packet data (Ethernet header)
404	uint8 *p = packet;
405	#if defined(__linux__)
406	if (is_ethertap) {
407	p += 2; // Linux ethertap has two random bytes before the packet
408	length -= 2;
409	}
410	#endif
411
412	// Get packet type
413	uint16 type = (p[12] << 8) \| p[13];
414
415	// Look for protocol
416	uint16 search_type = (type <= 1500 ? 0 : type);
417	if (net_protocols.find(search_type) == net_protocols.end())
418	continue;
419	uint32 handler = net_protocols[search_type];
420
421	// No default handler
422	if (handler == 0)
423	continue;
424
425	// Copy header to RHA
426	Host2Mac_memcpy(ether_data + ed_RHA, p, 14);
427	D(bug(" header %08x%04x %08x%04x %04x\n", ReadMacInt32(ether_data + ed_RHA), ReadMacInt16(ether_data + ed_RHA + 4), ReadMacInt32(ether_data + ed_RHA + 6), ReadMacInt16(ether_data + ed_RHA + 10), ReadMacInt16(ether_data + ed_RHA + 12)));
428
429	// Call protocol handler
430	M68kRegisters r;
431	r.d[0] = type; // Packet type
432	r.d[1] = length - 14; // Remaining packet length (without header, for ReadPacket)
433	r.a[0] = (uint32)p + 14; // Pointer to packet (host address, for ReadPacket)
434	r.a[3] = ether_data + ed_RHA + 14; // Pointer behind header in RHA
435	r.a[4] = ether_data + ed_ReadPacket; // Pointer to ReadPacket/ReadRest routines
436	D(bug(" calling protocol handler %08x, type %08x, length %08x, data %08x, rha %08x, read_packet %08x\n", handler, r.d[0], r.d[1], r.a[0], r.a[3], r.a[4]));
437	Execute68k(handler, &r);
438	}
439	}
440
441	// Acknowledge interrupt to reception thread
442	D(bug(" EtherIRQ done\n"));
443	sem_post(&int_ack);
444	}