src/Unix/ether_unix.cpp

/*
 *  ether_unix.cpp - Ethernet device driver, Unix specific stuff (Linux and FreeBSD)
 *
 *  Basilisk II (C) 1997-2001 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 <pthread.h>
#include <semaphore.h>
#include <errno.h>
#include <stdio.h>

#if defined(__FreeBSD__)
#include <sys/socket.h>
#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"

#define DEBUG 0
#include "debug.h"

#define MONITOR 0


// List of attached protocols
struct NetProtocol {
        NetProtocol *next;
        uint16 type;
        uint32 handler;
};

static NetProtocol *prot_list = NULL;


// 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

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


/*
 *  Find protocol in list
 */

static NetProtocol *find_protocol(uint16 type)
{
        // All 802.2 types are the same
        if (type <= 1500)
                type = 0;

        // Search list (we could use hashing here but there are usually only three
        // handlers installed: 0x0000 for AppleTalk and 0x0800/0x0806 for TCP/IP)
        NetProtocol *p = prot_list;
        while (p) {
                if (p->type == type)
                        return p;
                p = p->next;
        }
        return NULL;
}


/*
 *  Remove all protocols
 */

static void remove_all_protocols(void)
{
        NetProtocol *p = prot_list;
        while (p) {
                NetProtocol *next = p->next;
                delete p;
                p = next;
        }
        prot_list = NULL;
}


/*
 *  Initialization
 */

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

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

        // 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 (sem_init(&int_ack, 0, 0) < 0) {
                printf("WARNING: Cannot init semaphore");
                goto open_error;
        }
        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");
                goto open_error;
        }

        // Everything OK
        net_open = true;
        return;

open_error:
        if (thread_active) {
                pthread_cancel(ether_thread);
                pthread_join(ether_thread, NULL);
                sem_destroy(&int_ack);
                thread_active = false;
        }
        if (fd > 0) {
                close(fd);
                fd = -1;
        }
}


/*
 *  Deinitialization
 */

void EtherExit(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);

        // Remove all protocols
        remove_all_protocols();
}


/*
 *  Reset
 */

void EtherReset(void)
{
        remove_all_protocols();
}


/*
 *  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)
{
        // Already attached?
        NetProtocol *p = find_protocol(type);
        if (p != NULL)
                return lapProtErr;
        else {
                // No, create and attach
                p = new NetProtocol;
                p->next = prot_list;
                p->type = type;
                p->handler = handler;
                prot_list = p;
                return noErr;
        }
}


/*
 *  Detach protocol handler
 */

int16 ether_detach_ph(uint16 type)
{
        NetProtocol *p = find_protocol(type);
        if (p != NULL) {
                NetProtocol *q = prot_list;
                if (p == q) {
                        prot_list = p->next;
                        delete p;
                        return noErr;
                }
                while (q) {
                        if (q->next == p) {
                                q->next = p->next;
                                delete p;
                                return noErr;
                        }
                        q = q->next;
                }
                return lapProtErr;
        } else
                return lapProtErr;
}


/*
 *  Transmit raw ethernet packet
 */

int16 ether_write(uint32 wds)
{
        // Set source address
        uint32 hdr = ReadMacInt32(wds + 2);
        Host2Mac_memcpy(hdr + 6, ether_addr, 6);

        // 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
        for (;;) {
                int w = ReadMacInt16(wds);
                if (w == 0)
                        break;
                Mac2Host_memcpy(p, ReadMacInt32(wds + 2), w);
                len += w;
                p += w;
                wds += 6;
        }

#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;
}


/*
 *  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];
        for (;;) {

                // Read packet from sheep_net device
#if defined(__linux__)
                ssize_t length = read(fd, packet, is_ethertap ? 1516 : 1514);
#else
                ssize_t 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 = ntohs(*(uint16 *)(p + 12));

                // Look for protocol
                NetProtocol *prot = find_protocol(type);
                if (prot == NULL)
                        continue;

                // No default handler
                if (prot->handler == 0)
                        continue;

                // Copy header to RHA
                Host2Mac_memcpy(ether_data + ed_RHA, p, 14);
                D(bug(" header %08lx%04lx %08lx%04lx %04lx\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 %08lx, type %08lx, length %08lx, data %08lx, rha %08lx, read_packet %08lx\n", prot->handler, r.d[0], r.d[1], r.a[0], r.a[3], r.a[4]));
                Execute68k(prot->handler, &r);
        }

        // Acknowledge interrupt to reception thread
        D(bug(" EtherIRQ done\n"));
        sem_post(&int_ack);
}
Revision:	1.1
Committed:	2001-03-29T14:20:53Z (23 years, 7 months ago) by cebix
Branch:	MAIN
CVS Tags:	snapshot-29052001, release-0_9-1
Log Message:	- FreeBSD configure script cleanups [Michael Alyn Miller] - ether_linux.cpp moved and renamed to ether_unix.cpp, now also works with the tap driver under FreeBSD [Michael Alyn Miller] - fpu_x86_asm.h: fixed problem in with newer GCC pre-processors
#	User	Rev	Content
1	cebix	1.1	/*
2			* ether_unix.cpp - Ethernet device driver, Unix specific stuff (Linux and FreeBSD)
3			*
4			* Basilisk II (C) 1997-2001 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 <pthread.h>
26			#include <semaphore.h>
27			#include <errno.h>
28			#include <stdio.h>
29
30			#if defined(__FreeBSD__)
31			#include <sys/socket.h>
32			#include <net/if.h>
33			#endif
34
35			#include "cpu_emulation.h"
36			#include "main.h"
37			#include "macos_util.h"
38			#include "prefs.h"
39			#include "user_strings.h"
40			#include "ether.h"
41			#include "ether_defs.h"
42
43			#define DEBUG 0
44			#include "debug.h"
45
46			#define MONITOR 0
47
48
49			// List of attached protocols
50			struct NetProtocol {
51			NetProtocol *next;
52			uint16 type;
53			uint32 handler;
54			};
55
56			static NetProtocol *prot_list = NULL;
57
58
59			// Global variables
60			static int fd = -1; // fd of sheep_net device
61			static pthread_t ether_thread; // Packet reception thread
62			static pthread_attr_t ether_thread_attr; // Packet reception thread attributes
63			static bool thread_active = false; // Flag: Packet reception thread installed
64			static sem_t int_ack; // Interrupt acknowledge semaphore
65			static bool is_ethertap; // Flag: Ethernet device is ethertap
66
67			// Prototypes
68			static void receive_func(void arg);
69
70
71			/*
72			* Find protocol in list
73			*/
74
75			static NetProtocol *find_protocol(uint16 type)
76			{
77			// All 802.2 types are the same
78			if (type <= 1500)
79			type = 0;
80
81			// Search list (we could use hashing here but there are usually only three
82			// handlers installed: 0x0000 for AppleTalk and 0x0800/0x0806 for TCP/IP)
83			NetProtocol *p = prot_list;
84			while (p) {
85			if (p->type == type)
86			return p;
87			p = p->next;
88			}
89			return NULL;
90			}
91
92
93			/*
94			* Remove all protocols
95			*/
96
97			static void remove_all_protocols(void)
98			{
99			NetProtocol *p = prot_list;
100			while (p) {
101			NetProtocol *next = p->next;
102			delete p;
103			p = next;
104			}
105			prot_list = NULL;
106			}
107
108
109			/*
110			* Initialization
111			*/
112
113			void EtherInit(void)
114			{
115			int nonblock = 1;
116			char str[256];
117
118			// Do nothing if no Ethernet device specified
119			const char *name = PrefsFindString("ether");
120			if (name == NULL)
121			return;
122
123			// Is it Ethertap?
124			is_ethertap = (strncmp(name, "tap", 3) == 0);
125
126			// Open sheep_net or ethertap device
127			char dev_name[16];
128			if (is_ethertap)
129			sprintf(dev_name, "/dev/%s", name);
130			else
131			strcpy(dev_name, "/dev/sheep_net");
132			fd = open(dev_name, O_RDWR);
133			if (fd < 0) {
134			sprintf(str, GetString(STR_NO_SHEEP_NET_DRIVER_WARN), dev_name, strerror(errno));
135			WarningAlert(str);
136			goto open_error;
137			}
138
139			#if defined(__linux__)
140			// Attach sheep_net to selected Ethernet card
141			if (!is_ethertap && ioctl(fd, SIOCSIFLINK, name) < 0) {
142			sprintf(str, GetString(STR_SHEEP_NET_ATTACH_WARN), strerror(errno));
143			WarningAlert(str);
144			goto open_error;
145			}
146			#endif
147
148			// Set nonblocking I/O
149			ioctl(fd, FIONBIO, &nonblock);
150
151			// Get Ethernet address
152			if (is_ethertap) {
153			pid_t p = getpid(); // If configured for multicast, ethertap requires that the lower 32 bit of the Ethernet address are our PID
154			ether_addr[0] = 0xfe;
155			ether_addr[1] = 0xfd;
156			ether_addr[2] = p >> 24;
157			ether_addr[3] = p >> 16;
158			ether_addr[4] = p >> 8;
159			ether_addr[5] = p;
160			} else
161			ioctl(fd, SIOCGIFADDR, ether_addr);
162			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]));
163
164			// Start packet reception thread
165			if (sem_init(&int_ack, 0, 0) < 0) {
166			printf("WARNING: Cannot init semaphore");
167			goto open_error;
168			}
169			pthread_attr_init(&ether_thread_attr);
170			#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
171			if (geteuid() == 0) {
172			pthread_attr_setinheritsched(&ether_thread_attr, PTHREAD_EXPLICIT_SCHED);
173			pthread_attr_setschedpolicy(&ether_thread_attr, SCHED_FIFO);
174			struct sched_param fifo_param;
175			fifo_param.sched_priority = (sched_get_priority_min(SCHED_FIFO) + sched_get_priority_max(SCHED_FIFO)) / 2 + 1;
176			pthread_attr_setschedparam(&ether_thread_attr, &fifo_param);
177			}
178			#endif
179			thread_active = (pthread_create(&ether_thread, &ether_thread_attr, receive_func, NULL) == 0);
180			if (!thread_active) {
181			printf("WARNING: Cannot start Ethernet thread");
182			goto open_error;
183			}
184
185			// Everything OK
186			net_open = true;
187			return;
188
189			open_error:
190			if (thread_active) {
191			pthread_cancel(ether_thread);
192			pthread_join(ether_thread, NULL);
193			sem_destroy(&int_ack);
194			thread_active = false;
195			}
196			if (fd > 0) {
197			close(fd);
198			fd = -1;
199			}
200			}
201
202
203			/*
204			* Deinitialization
205			*/
206
207			void EtherExit(void)
208			{
209			// Stop reception thread
210			if (thread_active) {
211			pthread_cancel(ether_thread);
212			pthread_join(ether_thread, NULL);
213			sem_destroy(&int_ack);
214			thread_active = false;
215			}
216
217			// Close sheep_net device
218			if (fd > 0)
219			close(fd);
220
221			// Remove all protocols
222			remove_all_protocols();
223			}
224
225
226			/*
227			* Reset
228			*/
229
230			void EtherReset(void)
231			{
232			remove_all_protocols();
233			}
234
235
236			/*
237			* Add multicast address
238			*/
239
240			int16 ether_add_multicast(uint32 pb)
241			{
242			if (ioctl(fd, SIOCADDMULTI, Mac2HostAddr(pb + eMultiAddr)) < 0) {
243			D(bug("WARNING: Couldn't enable multicast address\n"));
244			if (is_ethertap)
245			return noErr;
246			else
247			return eMultiErr;
248			} else
249			return noErr;
250			}
251
252
253			/*
254			* Delete multicast address
255			*/
256
257			int16 ether_del_multicast(uint32 pb)
258			{
259			if (ioctl(fd, SIOCDELMULTI, Mac2HostAddr(pb + eMultiAddr)) < 0) {
260			D(bug("WARNING: Couldn't disable multicast address\n"));
261			return eMultiErr;
262			} else
263			return noErr;
264			}
265
266
267			/*
268			* Attach protocol handler
269			*/
270
271			int16 ether_attach_ph(uint16 type, uint32 handler)
272			{
273			// Already attached?
274			NetProtocol *p = find_protocol(type);
275			if (p != NULL)
276			return lapProtErr;
277			else {
278			// No, create and attach
279			p = new NetProtocol;
280			p->next = prot_list;
281			p->type = type;
282			p->handler = handler;
283			prot_list = p;
284			return noErr;
285			}
286			}
287
288
289			/*
290			* Detach protocol handler
291			*/
292
293			int16 ether_detach_ph(uint16 type)
294			{
295			NetProtocol *p = find_protocol(type);
296			if (p != NULL) {
297			NetProtocol *q = prot_list;
298			if (p == q) {
299			prot_list = p->next;
300			delete p;
301			return noErr;
302			}
303			while (q) {
304			if (q->next == p) {
305			q->next = p->next;
306			delete p;
307			return noErr;
308			}
309			q = q->next;
310			}
311			return lapProtErr;
312			} else
313			return lapProtErr;
314			}
315
316
317			/*
318			* Transmit raw ethernet packet
319			*/
320
321			int16 ether_write(uint32 wds)
322			{
323			// Set source address
324			uint32 hdr = ReadMacInt32(wds + 2);
325			Host2Mac_memcpy(hdr + 6, ether_addr, 6);
326
327			// Copy packet to buffer
328			uint8 packet[1516], *p = packet;
329			int len = 0;
330			#if defined(__linux__)
331			if (is_ethertap) {
332			*p++ = 0; // Linux ethertap discards the first 2 bytes
333			*p++ = 0;
334			len += 2;
335			}
336			#endif
337			for (;;) {
338			int w = ReadMacInt16(wds);
339			if (w == 0)
340			break;
341			Mac2Host_memcpy(p, ReadMacInt32(wds + 2), w);
342			len += w;
343			p += w;
344			wds += 6;
345			}
346
347			#if MONITOR
348			bug("Sending Ethernet packet:\n");
349			for (int i=0; i<len; i++) {
350			bug("%02x ", packet[i]);
351			}
352			bug("\n");
353			#endif
354
355			// Transmit packet
356			if (write(fd, packet, len) < 0) {
357			D(bug("WARNING: Couldn't transmit packet\n"));
358			return excessCollsns;
359			} else
360			return noErr;
361			}
362
363
364			/*
365			* Packet reception thread
366			*/
367
368			static void receive_func(void arg)
369			{
370			for (;;) {
371
372			// Wait for packets to arrive
373			struct pollfd pf = {fd, POLLIN, 0};
374			int res = poll(&pf, 1, -1);
375			if (res <= 0)
376			break;
377
378			// Trigger Ethernet interrupt
379			D(bug(" packet received, triggering Ethernet interrupt\n"));
380			SetInterruptFlag(INTFLAG_ETHER);
381			TriggerInterrupt();
382
383			// Wait for interrupt acknowledge by EtherInterrupt()
384			sem_wait(&int_ack);
385			}
386			return NULL;
387			}
388
389
390			/*
391			* Ethernet interrupt - activate deferred tasks to call IODone or protocol handlers
392			*/
393
394			void EtherInterrupt(void)
395			{
396			D(bug("EtherIRQ\n"));
397
398			// Call protocol handler for received packets
399			uint8 packet[1516];
400			for (;;) {
401
402			// Read packet from sheep_net device
403			#if defined(__linux__)
404			ssize_t length = read(fd, packet, is_ethertap ? 1516 : 1514);
405			#else
406			ssize_t length = read(fd, packet, 1514);
407			#endif
408			if (length < 14)
409			break;
410
411			#if MONITOR
412			bug("Receiving Ethernet packet:\n");
413			for (int i=0; i<length; i++) {
414			bug("%02x ", packet[i]);
415			}
416			bug("\n");
417			#endif
418
419			// Pointer to packet data (Ethernet header)
420			uint8 *p = packet;
421			#if defined(__linux__)
422			if (is_ethertap) {
423			p += 2; // Linux ethertap has two random bytes before the packet
424			length -= 2;
425			}
426			#endif
427
428			// Get packet type
429			uint16 type = ntohs((uint16 )(p + 12));
430
431			// Look for protocol
432			NetProtocol *prot = find_protocol(type);
433			if (prot == NULL)
434			continue;
435
436			// No default handler
437			if (prot->handler == 0)
438			continue;
439
440			// Copy header to RHA
441			Host2Mac_memcpy(ether_data + ed_RHA, p, 14);
442			D(bug(" header %08lx%04lx %08lx%04lx %04lx\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)));
443
444			// Call protocol handler
445			M68kRegisters r;
446			r.d[0] = type; // Packet type
447			r.d[1] = length - 14; // Remaining packet length (without header, for ReadPacket)
448			r.a[0] = (uint32)p + 14; // Pointer to packet (host address, for ReadPacket)
449			r.a[3] = ether_data + ed_RHA + 14; // Pointer behind header in RHA
450			r.a[4] = ether_data + ed_ReadPacket; // Pointer to ReadPacket/ReadRest routines
451			D(bug(" calling protocol handler %08lx, type %08lx, length %08lx, data %08lx, rha %08lx, read_packet %08lx\n", prot->handler, r.d[0], r.d[1], r.a[0], r.a[3], r.a[4]));
452			Execute68k(prot->handler, &r);
453			}
454
455			// Acknowledge interrupt to reception thread
456			D(bug(" EtherIRQ done\n"));
457			sem_post(&int_ack);
458			}