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ETHER, PDP11, VAX: Added a built-in loopback agent which all ethernet devices can leverage to detect MAC address conflicts.

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Some of this behavior was previously available in the pdp11_xq simulation for the DELQA device variants, but not the DEQNA.  This adds the behavior for all ethernet devices.

The helps to avoid MAC address conflicts since the Ethernet physical address is completely user settable, and starts with a static value.  Multiple simulators on the same LAN will have conflicting addresses if they don't specifically set unique values.
This commit is contained in:
Mark Pizzolato 2014-05-29 09:42:02 -07:00
parent f8020a2c4c
commit d57e37a392
2 changed files with 142 additions and 33 deletions
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117
sim_ether.c
View file

@ -562,6 +562,11 @@ void eth_packet_trace(ETH_DEV* dev, const uint8 *msg, int len, char* txt)
eth_packet_trace_ex(dev, msg, len, txt, 0, dev->dbit);
}
void eth_packet_trace_detail(ETH_DEV* dev, const uint8 *msg, int len, char* txt)
{
eth_packet_trace_ex(dev, msg, len, txt, 1 , dev->dbit);
}
char* eth_getname(int number, char* name)
{
ETH_LIST list[ETH_MAX_DEVICE];
@ -2070,12 +2075,23 @@ fprintf (st, " sim> ATTACH %s en0\n\n", dptr->name);
return SCPE_OK;
}
static int _eth_rand_byte()
{
static int rand_initialized = 0;
if (!rand_initialized)
srand((unsigned int)sim_os_msec());
return (rand() & 0xFF);
}
t_stat eth_check_address_conflict (ETH_DEV* dev,
ETH_MAC* const mac)
{
ETH_PACK send, recv;
t_stat status;
uint32 i;
int responses = 0;
uint32 offset, function;
char mac_string[32];
eth_mac_fmt(mac, mac_string);
@ -2144,13 +2160,19 @@ sim_debug(dev->dbit, dev->dptr, "Determining Address Conflict for MAC address: %
/* build a loopback forward request packet */
memset (&send, 0, sizeof(ETH_PACK));
send.len = ETH_MIN_PACKET; /* minimum packet size */
for (i=0; i<send.len; i++)
send.msg[i] = _eth_rand_byte();
memcpy(&send.msg[0], mac, sizeof(ETH_MAC)); /* target address */
memcpy(&send.msg[6], mac, sizeof(ETH_MAC)); /* source address */
send.msg[12] = 0x90; /* loopback packet type */
send.msg[13] = 0;
send.msg[14] = 0; /* Offset */
send.msg[15] = 0;
send.msg[16] = 2; /* Forward */
send.msg[17] = 0;
memcpy(&send.msg[18], mac, sizeof(ETH_MAC)); /* Forward Destination */
send.msg[24] = 1; /* Reply */
send.msg[25] = 0;
eth_filter(dev, 1, (ETH_MAC *)mac, 0, 0);
@ -2170,14 +2192,21 @@ if (status != SCPE_OK) {
sim_os_ms_sleep (300); /* time for a conflicting host to respond */
eth_packet_trace_detail (dev, send.msg, send.len, "Sent-Address-Check");
/* empty the read queue and count the responses */
do {
memset (&recv, 0, sizeof(ETH_PACK));
status = eth_read (dev, &recv, NULL);
eth_packet_trace_detail (dev, recv.msg, recv.len, "Recv-Address-Check");
offset = 16 + (recv.msg[14] | (recv.msg[15] << 8));
function = 0;
if ((offset+2) < recv.len)
function = recv.msg[offset] | (recv.msg[offset+1] << 8);
if (((0 == memcmp(send.msg+12, recv.msg+12, 2)) && /* Protocol Match */
(0 == memcmp(send.msg, recv.msg+6, 6)) && /* Source Match */
(0 == memcmp(send.msg+6, recv.msg, 6))) || /* Destination Match */
(0 == memcmp(send.msg, recv.msg, 14))) /* Packet Match (Reflection) */
(function == 1) && /* Function is Reply */
(0 == memcmp(&send.msg[offset], &recv.msg[offset], send.len-offset))) || /* Content Match */
(0 == memcmp(send.msg, recv.msg, send.len))) /* Packet Match (Reflection) */
responses++;
} while (recv.len > 0);
@ -2190,7 +2219,7 @@ t_stat eth_reflect(ETH_DEV* dev)
/* Test with an address no NIC should have. */
/* We do this to avoid reflections from the wire, */
/* in the event that a simulated NIC has a MAC address conflict. */
ETH_MAC mac = {0xfe,0xff,0xff,0xff,0xff,0xfe};
static ETH_MAC mac = {0xfe,0xff,0xff,0xff,0xff,0xfe};
sim_debug(dev->dbit, dev->dptr, "Determining Reflections...\n");
@ -2215,14 +2244,18 @@ if (!packet) return SCPE_ARG;
/* make sure packet is acceptable length */
if ((packet->len >= ETH_MIN_PACKET) && (packet->len <= ETH_MAX_PACKET)) {
int loopback_self_frame = LOOPBACK_SELF_FRAME(packet->msg, packet->msg);
int loopback_physical_response = LOOPBACK_PHYSICAL_RESPONSE(dev, packet->msg);
eth_packet_trace (dev, packet->msg, packet->len, "writing");
/* record sending of loopback packet (done before actual send to avoid race conditions with receiver) */
if (loopback_self_frame) {
if (dev->have_host_nic_phy_addr) {
if (loopback_self_frame || loopback_physical_response) {
/* Direct loopback responses to the host physical address since our physical address
may not have been learned yet. */
if (loopback_self_frame && dev->have_host_nic_phy_addr) {
memcpy(&packet->msg[6], dev->host_nic_phy_hw_addr, sizeof(ETH_MAC));
memcpy(&packet->msg[18], dev->host_nic_phy_hw_addr, sizeof(ETH_MAC));
eth_packet_trace (dev, packet->msg, packet->len, "writing-fixed");
}
#ifdef USE_READER_THREAD
pthread_mutex_lock (&dev->self_lock);
@ -2772,6 +2805,65 @@ switch (IP->proto) {
}
}
static int
_eth_process_loopback (ETH_DEV* dev, const u_char* data, uint32 len)
{
int protocol = data[12] | (data[13] << 8);
ETH_PACK response;
uint32 offset, function;
if (protocol != 0x0090) /* !ethernet loopback */
return 0;
if (LOOPBACK_REFLECTION_TEST_PACKET(dev, data))
return 0; /* Ignore reflection check packet */
offset = 16 + (data[14] | (data[15] << 8));
if (offset >= len)
return 0;
function = data[offset] | (data[offset+1] << 8);
if (function != 2) /*forward*/
return 0;
/* The only packets we should be responding to are ones which
we received due to them being directed to our physical MAC address,
OR the Broadcast address OR to a Multicast address we're listening to
(we may receive others if we're in promiscuous mode, but shouldn't
respond to them) */
if ((0 == (data[0]&1)) && /* Multicast or Broadcast */
(0 != memcmp(dev->filter_address[0], data, sizeof(ETH_MAC))))
return 0;
/* Attempts to forward to multicast or broadcast addresses are explicitly
ignored by consuming the packet and doing nothing else */
if (data[offset+2]&1)
return 1;
eth_packet_trace (dev, data, len, "rcvd");
sim_debug(dev->dbit, dev->dptr, "_eth_process_loopback()\n");
/* create forward response packet */
memset(&response, 0, sizeof(response));
response.len = len;
memcpy(response.msg, data, len);
memcpy(&response.msg[0], &response.msg[offset+2], sizeof(ETH_MAC));
memcpy(&response.msg[6], dev->filter_address[0], sizeof(ETH_MAC));
offset += 8 - 16; /* Account for the Ethernet Header and Offset value in this number */
response.msg[14] = offset & 0xFF;
response.msg[15] = (offset >> 8) & 0xFF;
/* send response packet */
eth_write(dev, &response, NULL);
eth_packet_trace(dev, response.msg, response.len, ((function == 1) ? "loopbackreply" : "loopbackforward"));
++dev->loopback_packets_processed;
return 1;
}
static void
_eth_callback(u_char* info, const struct pcap_pkthdr* header, const u_char* data)
{
@ -2781,10 +2873,12 @@ int from_me = 0;
int i;
int bpf_used;
if ((dev->have_host_nic_phy_addr) &&
(LOOPBACK_PHYSICAL_RESPONSE(dev->host_nic_phy_hw_addr, dev->physical_addr, data))) {
if (LOOPBACK_PHYSICAL_RESPONSE(dev, data)) {
u_char *datacopy = (u_char *)malloc(header->len);
/* Since we changed the outgoing loopback packet to have the physical MAC address of the
host's interface instead of the programmatically set physical address of this pseudo
device, we restore parts of the modified packet back as needed */
memcpy(datacopy, data, header->len);
memcpy(datacopy, dev->physical_addr, sizeof(ETH_MAC));
memcpy(datacopy+18, dev->physical_addr, sizeof(ETH_MAC));
@ -2832,8 +2926,7 @@ switch (dev->eth_api) {
/* detect reception of loopback packet to our physical address */
if ((LOOPBACK_SELF_FRAME(dev->physical_addr, data)) ||
(dev->have_host_nic_phy_addr &&
LOOPBACK_PHYSICAL_REFLECTION(dev->host_nic_phy_hw_addr, data))) {
(LOOPBACK_PHYSICAL_REFLECTION(dev, data))) {
#ifdef USE_READER_THREAD
pthread_mutex_lock (&dev->self_lock);
#endif
@ -2860,6 +2953,8 @@ if (bpf_used ? to_me : (to_me && !from_me)) {
++dev->jumbo_truncated;
return;
}
if (_eth_process_loopback(dev, data, header->len))
return;
#if defined (USE_READER_THREAD)
if (1) {
int crc_len = 0;
@ -3415,6 +3510,8 @@ if (dev->packets_sent)
fprintf(st, " Packets Sent: %d\n", dev->packets_sent);
if (dev->packets_received)
fprintf(st, " Packets Received: %d\n", dev->packets_received);
if (dev->loopback_packets_processed)
fprintf(st, " Loopback Packets: %d\n", dev->loopback_packets_processed);
#if defined(USE_READER_THREAD)
fprintf(st, " Asynch Interrupts: %s\n", dev->asynch_io?"Enabled":"Disabled");
if (dev->asynch_io)

56
sim_ether.h
View file

@ -159,30 +159,41 @@
#define ETH_MIN_JUMBO_FRAME ETH_MAX_PACKET /* Threshold size for Jumbo Frame Processing */
#define LOOPBACK_SELF_FRAME(phy_mac, msg) \
(((msg)[12] == 0x90) && ((msg)[13] == 0x00) && \
((msg)[14] == 0x00) && ((msg)[15] == 0x00) && \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && \
(memcmp(phy_mac, (msg), 6) == 0) && \
(memcmp(phy_mac, (msg)+6, 6) == 0) && \
(memcmp(phy_mac, (msg)+18, 6) == 0))
(((msg)[12] == 0x90) && ((msg)[13] == 0x00) && /* Ethernet Loopback */ \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && /* Forward Function */ \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && /* Next Function - Reply */ \
(memcmp(phy_mac, (msg), 6) == 0) && /* Ethernet Destination */ \
(memcmp(phy_mac, (msg)+6, 6) == 0) && /* Ethernet Source */ \
(memcmp(phy_mac, (msg)+18, 6) == 0)) /* Forward Address */
#define LOOPBACK_PHYSICAL_RESPONSE(host_phy, phy_mac, msg) \
(((msg)[12] == 0x90) && ((msg)[13] == 0x00) && \
((msg)[14] == 0x08) && ((msg)[15] == 0x00) && \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && \
(memcmp(host_phy, (msg)+18, 6) == 0) && \
(memcmp(host_phy, (msg), 6) == 0) && \
(memcmp(phy_mac, (msg)+6, 6) == 0))
#define LOOPBACK_PHYSICAL_RESPONSE(dev, msg) \
((dev->have_host_nic_phy_addr) && \
((msg)[12] == 0x90) && ((msg)[13] == 0x00) && /* Ethernet Loopback */ \
((msg)[14] == 0x08) && ((msg)[15] == 0x00) && /* Skipcount - 8 */ \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && /* Last Function - Forward */ \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && /* Function - Reply */ \
(memcmp(dev->host_nic_phy_hw_addr, (msg)+18, 6) == 0) && /* Forward Address - Host MAC */\
(memcmp(dev->host_nic_phy_hw_addr, (msg), 6) == 0) && /* Ethernet Source - Host MAC */\
(memcmp(dev->physical_addr, (msg)+6, 6) == 0)) /* Ethernet Source */
#define LOOPBACK_PHYSICAL_REFLECTION(host_phy, msg) \
(((msg)[12] == 0x90) && ((msg)[13] == 0x00) && \
((msg)[14] == 0x00) && ((msg)[15] == 0x00) && \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && \
(memcmp(host_phy, (msg)+6, 6) == 0) && \
(memcmp(host_phy, (msg)+18, 6) == 0))
#define LOOPBACK_PHYSICAL_REFLECTION(dev, msg) \
((dev->have_host_nic_phy_addr) && \
((msg)[12] == 0x90) && ((msg)[13] == 0x00) && /* Ethernet Loopback */ \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && /* Forward Function */ \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && /* Next Function - Reply */ \
(memcmp(dev->host_nic_phy_hw_addr, (msg)+6, 6) == 0) && /* Ethernet Source - Host MAC */\
(memcmp(dev->host_nic_phy_hw_addr, (msg)+18, 6) == 0)) /* Forward Address - Host MAC */
#define LOOPBACK_REFLECTION_TEST_PACKET(dev, msg) \
((dev->have_host_nic_phy_addr) && \
((msg)[12] == 0x90) && ((msg)[13] == 0x00) && /* Ethernet Loopback */ \
((msg)[14] == 0x00) && ((msg)[15] == 0x00) && /* Skipcount - 0 */ \
((msg)[16] == 0x02) && ((msg)[17] == 0x00) && /* Forward Function */ \
((msg)[24] == 0x01) && ((msg)[25] == 0x00) && /* Next Function - Reply */ \
((msg)[00] == 0xFE) && ((msg)[01] == 0xFF) && /* Ethernet Destination - Reflection Test MAC */\
((msg)[02] == 0xFF) && ((msg)[03] == 0xFF) && \
((msg)[04] == 0xFF) && ((msg)[05] == 0xFE) && \
(memcmp(dev->host_nic_phy_hw_addr, (msg)+6, 6) == 0)) /* Ethernet Source - Host MAC */
struct eth_packet {
uint8 msg[ETH_FRAME_SIZE]; /* ethernet frame (message) */
@ -252,6 +263,7 @@ struct eth_device {
uint32 jumbo_truncated; /* Giant Frames too big for capture buffer - Dropped */
uint32 packets_sent; /* Total Packets Sent */
uint32 packets_received; /* Total Packets Received */
uint32 loopback_packets_processed; /* Total Loopback Packets Processed */
DEVICE* dptr; /* device ethernet is attached to */
uint32 dbit; /* debugging bit */
int reflections; /* packet reflections on interface */