#include <minmax.h>
#include <net.h>
#include "pxe.h"
#include "url.h"
#include "tftp.h"
const uint8_t TimeoutTable[] = {
2, 2, 3, 3, 4, 5, 6, 7, 9, 10, 12, 15, 18, 21, 26, 31, 37, 44,
53, 64, 77, 92, 110, 132, 159, 191, 229, 255, 255, 255, 255, 0
};
struct tftp_packet {
uint16_t opcode;
uint16_t serial;
char data[];
};
static void tftp_error(struct inode *file, uint16_t errnum,
const char *errstr);
static void tftp_close_file(struct inode *inode)
{
struct pxe_pvt_inode *socket = PVT(inode);
if (!socket->tftp_goteof) {
tftp_error(inode, 0, "No error, file close");
}
core_udp_close(socket);
}
/**
* Send an ERROR packet. This is used to terminate a connection.
*
* @inode: Inode structure
* @errnum: Error number (network byte order)
* @errstr: Error string (included in packet)
*/
static void tftp_error(struct inode *inode, uint16_t errnum,
const char *errstr)
{
static struct {
uint16_t err_op;
uint16_t err_num;
char err_msg[64];
} __packed err_buf;
int len = min(strlen(errstr), sizeof(err_buf.err_msg)-1);
struct pxe_pvt_inode *socket = PVT(inode);
err_buf.err_op = TFTP_ERROR;
err_buf.err_num = errnum;
memcpy(err_buf.err_msg, errstr, len);
err_buf.err_msg[len] = '\0';
core_udp_send(socket, &err_buf, 4 + len + 1);
}
/**
* Send ACK packet. This is a common operation and so is worth canning.
*
* @param: inode, Inode pointer
* @param: ack_num, Packet # to ack (host byte order)
*
*/
static void ack_packet(struct inode *inode, uint16_t ack_num)
{
static uint16_t ack_packet_buf[2];
struct pxe_pvt_inode *socket = PVT(inode);
/* Packet number to ack */
ack_packet_buf[0] = TFTP_ACK;
ack_packet_buf[1] = htons(ack_num);
core_udp_send(socket, ack_packet_buf, 4);
}
/*
* Get a fresh packet if the buffer is drained, and we haven't hit
* EOF yet. The buffer should be filled immediately after draining!
*/
static void tftp_get_packet(struct inode *inode)
{
uint16_t last_pkt;
const uint8_t *timeout_ptr;
uint8_t timeout;
uint16_t buffersize;
uint16_t serial;
jiffies_t oldtime;
struct tftp_packet *pkt = NULL;
uint16_t buf_len;
struct pxe_pvt_inode *socket = PVT(inode);
uint16_t src_port;
uint32_t src_ip;
int err;
/*
* Start by ACKing the previous packet; this should cause
* the next packet to be sent.
*/
timeout_ptr = TimeoutTable;
timeout = *timeout_ptr++;
oldtime = jiffies();
ack_again:
ack_packet(inode, socket->tftp_lastpkt);
while (timeout) {
buf_len = socket->tftp_blksize + 4;
err = core_udp_recv(socket, socket->tftp_pktbuf, &buf_len,
&src_ip, &src_port);
if (err) {
jiffies_t now = jiffies();
if (now-oldtime >= timeout) {
oldtime = now;
timeout = *timeout_ptr++;
if (!timeout)
break;
goto ack_again;
}
continue;
}
if (buf_len < 4) /* Bad size for a DATA packet */
continue;
pkt = (struct tftp_packet *)(socket->tftp_pktbuf);
if (pkt->opcode != TFTP_DATA) /* Not a data packet */
continue;
/* If goes here, recevie OK, break */
break;
}
/* time runs out */
if (timeout == 0)
kaboom();
last_pkt = socket->tftp_lastpkt;
last_pkt++;
serial = ntohs(pkt->serial);
if (serial != last_pkt) {
/*
* Wrong packet, ACK the packet and try again.
* This is presumably because the ACK got lost,
* so the server just resent the previous packet.
*/
#if 0
printf("Wrong packet, wanted %04x, got %04x\n", \
htons(last_pkt), htons(*(uint16_t *)(data+2)));
#endif
goto ack_again;
}
/* It's the packet we want. We're also EOF if the size < blocksize */
socket->tftp_lastpkt = last_pkt; /* Update last packet number */
buffersize = buf_len - 4; /* Skip TFTP header */
socket->tftp_dataptr = socket->tftp_pktbuf + 4;
socket->tftp_filepos += buffersize;
socket->tftp_bytesleft = buffersize;
if (buffersize < socket->tftp_blksize) {
/* it's the last block, ACK packet immediately */
ack_packet(inode, serial);
/* Make sure we know we are at end of file */
inode->size = socket->tftp_filepos;
socket->tftp_goteof = 1;
tftp_close_file(inode);
}
}
const struct pxe_conn_ops tftp_conn_ops = {
.fill_buffer = tftp_get_packet,
.close = tftp_close_file,
};
/**
* Open a TFTP connection to the server
*
* @param:inode, the inode to store our state in
* @param:ip, the ip to contact to get the file
* @param:filename, the file we wanna open
*
* @out: open_file_t structure, stores in file->open_file
* @out: the lenght of this file, stores in file->file_len
*
*/
void tftp_open(struct url_info *url, int flags, struct inode *inode,
const char **redir)
{
struct pxe_pvt_inode *socket = PVT(inode);
char *buf;
uint16_t buf_len;
char *p;
char *options;
char *data;
static const char rrq_tail[] = "octet\0""tsize\0""0\0""blksize\0""1408";
char rrq_packet_buf[2+2*FILENAME_MAX+sizeof rrq_tail];
char reply_packet_buf[PKTBUF_SIZE];
int err;
int buffersize;
int rrq_len;
const uint8_t *timeout_ptr;
jiffies_t timeout;
jiffies_t oldtime;
uint16_t opcode;
uint16_t blk_num;
uint64_t opdata;
uint16_t src_port;
uint32_t src_ip;
(void)redir; /* TFTP does not redirect */
(void)flags;
if (url->type != URL_OLD_TFTP) {
/*
* The TFTP URL specification allows the TFTP to end with a
* ;mode= which we just ignore.
*/
url_unescape(url->path, ';');
}
if (!url->port)
url->port = TFTP_PORT;
socket->ops = &tftp_conn_ops;
if (core_udp_open(socket))
return;
buf = rrq_packet_buf;
*(uint16_t *)buf = TFTP_RRQ; /* TFTP opcode */
buf += 2;
buf = stpcpy(buf, url->path);
buf++; /* Point *past* the final NULL */
memcpy(buf, rrq_tail, sizeof rrq_tail);
buf += sizeof rrq_tail;
rrq_len = buf - rrq_packet_buf;
timeout_ptr = TimeoutTable; /* Reset timeout */
sendreq:
timeout = *timeout_ptr++;
if (!timeout)
return; /* No file available... */
oldtime = jiffies();
core_udp_sendto(socket, rrq_packet_buf, rrq_len, url->ip, url->port);
/* If the WRITE call fails, we let the timeout take care of it... */
wait_pkt:
for (;;) {
buf_len = sizeof(reply_packet_buf);
err = core_udp_recv(socket, reply_packet_buf, &buf_len,
&src_ip, &src_port);
if (err) {
jiffies_t now = jiffies();
if (now - oldtime >= timeout)
goto sendreq;
} else {
/* Make sure the packet actually came from the server and
is long enough for a TFTP opcode */
dprintf("tftp_open: got packet buflen=%d\n", buf_len);
if ((src_ip == url->ip) && (buf_len >= 2))
break;
}
}
core_udp_disconnect(socket);
core_udp_connect(socket, src_ip, src_port);
/* filesize <- -1 == unknown */
inode->size = -1;
socket->tftp_blksize = TFTP_BLOCKSIZE;
buffersize = buf_len - 2; /* bytes after opcode */
/*
* Get the opcode type, and parse it
*/
opcode = *(uint16_t *)reply_packet_buf;
switch (opcode) {
case TFTP_ERROR:
inode->size = 0;
goto done; /* ERROR reply; don't try again */
case TFTP_DATA:
/*
* If the server doesn't support any options, we'll get a
* DATA reply instead of OACK. Stash the data in the file
* buffer and go with the default value for all options...
*
* We got a DATA packet, meaning no options are
* suported. Save the data away and consider the
* length undefined, *unless* this is the only
* data packet...
*/
buffersize -= 2;
if (buffersize < 0)
goto wait_pkt;
data = reply_packet_buf + 2;
blk_num = ntohs(*(uint16_t *)data);
data += 2;
if (blk_num != 1)
goto wait_pkt;
socket->tftp_lastpkt = blk_num;
if (buffersize > TFTP_BLOCKSIZE)
goto err_reply; /* Corrupt */
socket->tftp_pktbuf = malloc(TFTP_BLOCKSIZE + 4);
if (!socket->tftp_pktbuf)
goto err_reply; /* Internal error */
if (buffersize < TFTP_BLOCKSIZE) {
/*
* This is the final EOF packet, already...
* We know the filesize, but we also want to
* ack the packet and set the EOF flag.
*/
inode->size = buffersize;
socket->tftp_goteof = 1;
ack_packet(inode, blk_num);
}
socket->tftp_bytesleft = buffersize;
socket->tftp_dataptr = socket->tftp_pktbuf;
memcpy(socket->tftp_pktbuf, data, buffersize);
goto done;
case TFTP_OACK:
/*
* Now we need to parse the OACK packet to get the transfer
* and packet sizes.
*/
options = reply_packet_buf + 2;
p = options;
while (buffersize) {
const char *opt = p;
/*
* If we find an option which starts with a NUL byte,
* (a null option), we're either seeing garbage that some
* TFTP servers add to the end of the packet, or we have
* no clue how to parse the rest of the packet (what is
* an option name and what is a value?) In either case,
* discard the rest.
*/
if (!*opt)
goto done;
while (buffersize) {
if (!*p)
break; /* Found a final null */
*p++ |= 0x20;
buffersize--;
}
if (!buffersize)
break; /* Unterminated option */
/* Consume the terminal null */
p++;
buffersize--;
if (!buffersize)
break; /* No option data */
opdata = 0;
/* do convert a number-string to decimal number, just like atoi */
while (buffersize--) {
uint8_t d = *p++;
if (d == '\0')
break; /* found a final null */
d -= '0';
if (d > 9)
goto err_reply; /* Not a decimal digit */
opdata = opdata*10 + d;
}
if (!strcmp(opt, "tsize"))
inode->size = opdata;
else if (!strcmp(opt, "blksize"))
socket->tftp_blksize = opdata;
else
goto err_reply; /* Non-negotitated option returned,
no idea what it means ...*/
}
if (socket->tftp_blksize < 64 || socket->tftp_blksize > PKTBUF_SIZE)
goto err_reply;
/* Parsing successful, allocate buffer */
socket->tftp_pktbuf = malloc(socket->tftp_blksize + 4);
if (!socket->tftp_pktbuf)
goto err_reply;
else
goto done;
default:
printf("TFTP unknown opcode %d\n", ntohs(opcode));
goto err_reply;
}
err_reply:
/* Build the TFTP error packet */
tftp_error(inode, TFTP_EOPTNEG, "TFTP protocol error");
inode->size = 0;
done:
if (!inode->size)
core_udp_close(socket);
return;
}