#include "etherboot.h"
#include "proto.h"
#include "nic.h"
/*
* IMPORTANT
*
* This file should be rewritten to avoid the use of a bitmap. Our
* buffer routines can cope with being handed blocks in an arbitrary
* order, duplicate blocks, etc. This code could be substantially
* simplified by taking advantage of these features.
*
*/
#define SLAM_PORT 10000
#define SLAM_MULTICAST_IP ((239<<24)|(255<<16)|(1<<8)|(1<<0))
#define SLAM_MULTICAST_PORT 10000
#define SLAM_LOCAL_PORT 10000
/* Set the timeout intervals to at least 1 second so
* on a 100Mbit ethernet can receive 10000 packets
* in one second.
*
* The only case that is likely to trigger all of the nodes
* firing a nack packet is a slow server. The odds of this
* happening could be reduced being slightly smarter and utilizing
* the multicast channels for nacks. But that only improves the odds
* it doesn't improve the worst case. So unless this proves to be
* a common case having the control data going unicast should increase
* the odds of the data not being dropped.
*
* When doing exponential backoff we increase just the timeout
* interval and not the base to optimize for throughput. This is only
* expected to happen when the server is down. So having some nodes
* pinging immediately should get the transmission restarted quickly after a
* server restart. The host nic won't be to baddly swamped because of
* the random distribution of the nodes.
*
*/
#define SLAM_INITIAL_MIN_TIMEOUT (TICKS_PER_SEC/3)
#define SLAM_INITIAL_TIMEOUT_INTERVAL (TICKS_PER_SEC)
#define SLAM_BASE_MIN_TIMEOUT (2*TICKS_PER_SEC)
#define SLAM_BASE_TIMEOUT_INTERVAL (4*TICKS_PER_SEC)
#define SLAM_BACKOFF_LIMIT 5
#define SLAM_MAX_RETRIES 20
/*** Packets Formats ***
* Data Packet:
* transaction
* total bytes
* block size
* packet #
* data
*
* Status Request Packet
* transaction
* total bytes
* block size
*
* Status Packet
* received packets
* requested packets
* received packets
* requested packets
* ...
* received packets
* requested packtes
* 0
*/
#define MAX_HDR (7 + 7 + 7) /* transaction, total size, block size */
#define MIN_HDR (1 + 1 + 1) /* transactino, total size, block size */
#define MAX_SLAM_REQUEST MAX_HDR
#define MIN_SLAM_REQUEST MIN_HDR
#define MIN_SLAM_DATA (MIN_HDR + 1)
static struct slam_nack {
struct iphdr ip;
struct udphdr udp;
unsigned char data[ETH_MAX_MTU -
(sizeof(struct iphdr) + sizeof(struct udphdr))];
} nack;
struct slam_state {
unsigned char hdr[MAX_HDR];
unsigned long hdr_len;
unsigned long block_size;
unsigned long total_bytes;
unsigned long total_packets;
unsigned long received_packets;
struct buffer *buffer;
unsigned char *image;
unsigned char *bitmap;
} state;
static void init_slam_state(void)
{
state.hdr_len = sizeof(state.hdr);
memset(state.hdr, 0, state.hdr_len);
state.block_size = 0;
state.total_packets = 0;
state.received_packets = 0;
state.image = 0;
state.bitmap = 0;
}
struct slam_info {
struct sockaddr_in server;
struct sockaddr_in local;
struct sockaddr_in multicast;
int sent_nack;
struct buffer *buffer;
};
#define SLAM_TIMEOUT 0
#define SLAM_REQUEST 1
#define SLAM_DATA 2
static int await_slam(int ival __unused, void *ptr,
unsigned short ptype __unused, struct iphdr *ip,
struct udphdr *udp, struct tcphdr *tcp __unused)
{
struct slam_info *info = ptr;
if (!udp) {
return 0;
}
/* I can receive two kinds of packets here, a multicast data packet,
* or a unicast request for information
*/
/* Check for a data request packet */
if ((ip->dest.s_addr == arptable[ARP_CLIENT].ipaddr.s_addr) &&
(ntohs(udp->dest) == info->local.sin_port) &&
(nic.packetlen >=
ETH_HLEN +
sizeof(struct iphdr) +
sizeof(struct udphdr) +
MIN_SLAM_REQUEST)) {
return SLAM_REQUEST;
}
/* Check for a multicast data packet */
if ((ip->dest.s_addr == info->multicast.sin_addr.s_addr) &&
(ntohs(udp->dest) == info->multicast.sin_port) &&
(nic.packetlen >=
ETH_HLEN +
sizeof(struct iphdr) +
sizeof(struct udphdr) +
MIN_SLAM_DATA)) {
return SLAM_DATA;
}
#if 0
printf("#");
printf("dest: %@ port: %d len: %d\n",
ip->dest.s_addr, ntohs(udp->dest), nic.packetlen);
#endif
return 0;
}
static int slam_encode(
unsigned char **ptr, unsigned char *end, unsigned long value)
{
unsigned char *data = *ptr;
int bytes;
bytes = sizeof(value);
while ((bytes > 0) && ((0xff & (value >> ((bytes -1)<<3))) == 0)) {
bytes--;
}
if (bytes <= 0) {
bytes = 1;
}
if (data + bytes >= end) {
return -1;
}
if ((0xe0 & (value >> ((bytes -1)<<3))) == 0) {
/* packed together */
*data = (bytes << 5) | (value >> ((bytes -1)<<3));
} else {
bytes++;
*data = (bytes << 5);
}
bytes--;
data++;
while(bytes) {
*(data++) = 0xff & (value >> ((bytes -1)<<3));
bytes--;
}
*ptr = data;
return 0;
}
static int slam_skip(unsigned char **ptr, unsigned char *end)
{
int bytes;
if (*ptr >= end) {
return -1;
}
bytes = ((**ptr) >> 5) & 7;
if (bytes == 0) {
return -1;
}
if (*ptr + bytes >= end) {
return -1;
}
(*ptr) += bytes;
return 0;
}
static unsigned long slam_decode(unsigned char **ptr, unsigned char *end,
int *err)
{
unsigned long value;
unsigned bytes;
if (*ptr >= end) {
*err = -1;
}
bytes = ((**ptr) >> 5) & 7;
if ((bytes == 0) || (bytes > sizeof(unsigned long))) {
*err = -1;
return 0;
}
if ((*ptr) + bytes >= end) {
*err = -1;
}
value = (**ptr) & 0x1f;
bytes--;
(*ptr)++;
while(bytes) {
value <<= 8;
value |= **ptr;
(*ptr)++;
bytes--;
}
return value;
}
static long slam_sleep_interval(int exp)
{
long range;
long divisor;
long interval;
range = SLAM_BASE_TIMEOUT_INTERVAL;
if (exp < 0) {
divisor = RAND_MAX/SLAM_INITIAL_TIMEOUT_INTERVAL;
} else {
if (exp > SLAM_BACKOFF_LIMIT)
exp = SLAM_BACKOFF_LIMIT;
divisor = RAND_MAX/(range << exp);
}
interval = random()/divisor;
if (exp < 0) {
interval += SLAM_INITIAL_MIN_TIMEOUT;
} else {
interval += SLAM_BASE_MIN_TIMEOUT;
}
return interval;
}
static unsigned char *reinit_slam_state(
unsigned char *header, unsigned char *end)
{
unsigned long total_bytes;
unsigned long block_size;
unsigned long bitmap_len;
unsigned long max_packet_len;
unsigned char *data;
int err;
#if 0
printf("reinit\n");
#endif
data = header;
state.hdr_len = 0;
err = slam_skip(&data, end); /* transaction id */
total_bytes = slam_decode(&data, end, &err);
block_size = slam_decode(&data, end, &err);
if (err) {
printf("ALERT: slam size out of range\n");
return 0;
}
state.block_size = block_size;
state.total_bytes = total_bytes;
state.total_packets = (total_bytes + block_size - 1)/block_size;
state.hdr_len = data - header;
state.received_packets = 0;
data = state.hdr;
slam_encode(&data, &state.hdr[sizeof(state.hdr)], state.total_packets);
max_packet_len = data - state.hdr;
memcpy(state.hdr, header, state.hdr_len);
#if 0
printf("block_size: %ld\n", block_size);
printf("total_bytes: %ld\n", total_bytes);
printf("total_packets: %ld\n", state.total_packets);
printf("hdr_len: %ld\n", state.hdr_len);
printf("max_packet_len: %ld\n", max_packet_len);
#endif
if (state.block_size > ETH_MAX_MTU - (
sizeof(struct iphdr) + sizeof(struct udphdr) +
state.hdr_len + max_packet_len)) {
printf("ALERT: slam blocksize to large\n");
return 0;
}
bitmap_len = (state.total_packets + 1 + 7)/8;
state.image = phys_to_virt ( state.buffer->start );
/* We don't use the buffer routines properly yet; fake it */
state.buffer->fill = total_bytes;
state.bitmap = state.image + total_bytes;
if ((unsigned long)state.image < 1024*1024) {
printf("ALERT: slam filesize to large for available memory\n");
return 0;
}
memset(state.bitmap, 0, bitmap_len);
return header + state.hdr_len;
}
static int slam_recv_data(unsigned char *data)
{
unsigned long packet;
unsigned long data_len;
int err;
struct udphdr *udp;
udp = (struct udphdr *)&nic.packet[ETH_HLEN + sizeof(struct iphdr)];
err = 0;
packet = slam_decode(&data, &nic.packet[nic.packetlen], &err);
if (err || (packet > state.total_packets)) {
printf("ALERT: Invalid packet number\n");
return 0;
}
/* Compute the expected data length */
if (packet != state.total_packets -1) {
data_len = state.block_size;
} else {
data_len = state.total_bytes % state.block_size;
}
/* If the packet size is wrong drop the packet and then continue */
if (ntohs(udp->len) != (data_len + (data - (unsigned char*)udp))) {
printf("ALERT: udp packet is not the correct size\n");
return 1;
}
if (nic.packetlen < data_len + (data - nic.packet)) {
printf("ALERT: Ethernet packet shorter than data_len\n");
return 1;
}
if (data_len > state.block_size) {
data_len = state.block_size;
}
if (((state.bitmap[packet >> 3] >> (packet & 7)) & 1) == 0) {
/* Non duplicate packet */
state.bitmap[packet >> 3] |= (1 << (packet & 7));
memcpy(state.image + (packet*state.block_size), data, data_len);
state.received_packets++;
} else {
#ifdef MDEBUG
printf("<DUP>\n");
#endif
}
return 1;
}
static void transmit_nack(unsigned char *ptr, struct slam_info *info)
{
int nack_len;
/* Ensure the packet is null terminated */
*ptr++ = 0;
nack_len = ptr - (unsigned char *)&nack;
build_udp_hdr(info->server.sin_addr.s_addr, info->local.sin_port,
info->server.sin_port, 1, nack_len, &nack);
ip_transmit(nack_len, &nack);
#if defined(MDEBUG) && 0
printf("Sent NACK to %@ bytes: %d have:%ld/%ld\n",
info->server_ip, nack_len,
state.received_packets, state.total_packets);
#endif
}
static void slam_send_nack(struct slam_info *info)
{
unsigned char *ptr, *end;
/* Either I timed out or I was explicitly
* asked for a request packet
*/
ptr = &nack.data[0];
/* Reserve space for the trailling null */
end = &nack.data[sizeof(nack.data) -1];
if (!state.bitmap) {
slam_encode(&ptr, end, 0);
slam_encode(&ptr, end, 1);
}
else {
/* Walk the bitmap */
unsigned long i;
unsigned long len;
unsigned long max;
int value;
int last;
/* Compute the last bit and store an inverted trailer */
max = state.total_packets;
value = ((state.bitmap[(max -1) >> 3] >> ((max -1) & 7) ) & 1);
value = !value;
state.bitmap[max >> 3] &= ~(1 << (max & 7));
state.bitmap[max >> 3] |= value << (max & 7);
len = 0;
last = 1; /* Start with the received packets */
for(i = 0; i <= max; i++) {
value = (state.bitmap[i>>3] >> (i & 7)) & 1;
if (value == last) {
len++;
} else {
if (slam_encode(&ptr, end, len))
break;
last = value;
len = 1;
}
}
}
info->sent_nack = 1;
transmit_nack(ptr, info);
}
static void slam_send_disconnect(struct slam_info *info)
{
if (info->sent_nack) {
/* A disconnect is a packet with just the null terminator */
transmit_nack(&nack.data[0], info);
}
info->sent_nack = 0;
}
static int proto_slam(struct slam_info *info)
{
int retry;
long timeout;
init_slam_state();
state.buffer = info->buffer;
retry = -1;
rx_qdrain();
/* Arp for my server */
if (arptable[ARP_SERVER].ipaddr.s_addr != info->server.sin_addr.s_addr) {
arptable[ARP_SERVER].ipaddr.s_addr = info->server.sin_addr.s_addr;
memset(arptable[ARP_SERVER].node, 0, ETH_ALEN);
}
/* If I'm running over multicast join the multicast group */
join_group(IGMP_SERVER, info->multicast.sin_addr.s_addr);
for(;;) {
unsigned char *header;
unsigned char *data;
int type;
header = data = 0;
timeout = slam_sleep_interval(retry);
type = await_reply(await_slam, 0, info, timeout);
/* Compute the timeout for next time */
if (type == SLAM_TIMEOUT) {
/* If I timeouted recompute the next timeout */
if (retry++ > SLAM_MAX_RETRIES) {
return 0;
}
} else {
retry = 0;
}
if ((type == SLAM_DATA) || (type == SLAM_REQUEST)) {
/* Check the incomming packet and reinit the data
* structures if necessary.
*/
header = &nic.packet[ETH_HLEN +
sizeof(struct iphdr) + sizeof(struct udphdr)];
data = header + state.hdr_len;
if (memcmp(state.hdr, header, state.hdr_len) != 0) {
/* Something is fishy reset the transaction */
data = reinit_slam_state(header, &nic.packet[nic.packetlen]);
if (!data) {
return 0;
}
}
}
if (type == SLAM_DATA) {
if (!slam_recv_data(data)) {
return 0;
}
if (state.received_packets == state.total_packets) {
/* We are done get out */
break;
}
}
if ((type == SLAM_TIMEOUT) || (type == SLAM_REQUEST)) {
/* Either I timed out or I was explicitly
* asked by a request packet
*/
slam_send_nack(info);
}
}
slam_send_disconnect(info);
/* Leave the multicast group */
leave_group(IGMP_SERVER);
/* FIXME don't overwrite myself */
/* load file to correct location */
return 1;
}
static int url_slam ( char *url __unused, struct sockaddr_in *server,
char *file, struct buffer *buffer ) {
struct slam_info info;
/* Set the defaults */
info.server = *server;
info.multicast.sin_addr.s_addr = htonl(SLAM_MULTICAST_IP);
info.multicast.sin_port = SLAM_MULTICAST_PORT;
info.local.sin_addr.s_addr = arptable[ARP_CLIENT].ipaddr.s_addr;
info.local.sin_port = SLAM_LOCAL_PORT;
info.buffer = buffer;
info.sent_nack = 0;
if (file[0]) {
printf("\nBad url\n");
return 0;
}
return proto_slam(&info);
}
struct protocol slam_protocol __protocol = {
.name = "x-slam",
.default_port = SLAM_PORT,
.load = url_slam,
};
