/*
* TFTP data output backend
*/
#include <string.h>
#include <stdio.h>
#include <syslinux/pxe.h>
#include <syslinux/config.h>
#include <netinet/in.h>
#include <sys/times.h>
#include "backend.h"
enum tftp_opcode {
TFTP_RRQ = 1,
TFTP_WRQ = 2,
TFTP_DATA = 3,
TFTP_ACK = 4,
TFTP_ERROR = 5,
};
struct tftp_state {
uint32_t my_ip;
uint32_t srv_ip;
uint32_t srv_gw;
uint16_t my_port;
uint16_t srv_port;
uint16_t seq;
};
#define RCV_BUF 2048
static int send_ack_packet(struct tftp_state *tftp,
const void *pkt, size_t len)
{
com32sys_t ireg, oreg;
t_PXENV_UDP_WRITE *uw;
t_PXENV_UDP_READ *ur;
clock_t start;
static const clock_t timeouts[] = {
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, 0
};
const clock_t *timeout;
int err = -1;
uw = lmalloc(sizeof *uw + len);
ur = lmalloc(sizeof *ur + RCV_BUF);
memset(&ireg, 0, sizeof ireg);
ireg.eax.w[0] = 0x0009;
for (timeout = timeouts ; *timeout ; timeout++) {
memset(uw, 0, sizeof uw);
memcpy(uw+1, pkt, len);
uw->ip = tftp->srv_ip;
uw->gw = tftp->srv_gw;
uw->src_port = tftp->my_port;
uw->dst_port = tftp->srv_port ? tftp->srv_port : htons(69);
uw->buffer_size = len;
uw->buffer = FAR_PTR(uw+1);
ireg.ebx.w[0] = PXENV_UDP_WRITE;
ireg.es = SEG(uw);
ireg.edi.w[0] = OFFS(uw);
__intcall(0x22, &ireg, &oreg);
start = times(NULL);
do {
memset(ur, 0, sizeof ur);
ur->src_ip = tftp->srv_ip;
ur->dest_ip = tftp->my_ip;
ur->s_port = tftp->srv_port;
ur->d_port = tftp->my_port;
ur->buffer_size = RCV_BUF;
ur->buffer = FAR_PTR(ur+1);
ireg.ebx.w[0] = PXENV_UDP_READ;
ireg.es = SEG(ur);
ireg.edi.w[0] = OFFS(ur);
__intcall(0x22, &ireg, &oreg);
if (!(oreg.eflags.l & EFLAGS_CF) &&
ur->status == PXENV_STATUS_SUCCESS &&
tftp->srv_ip == ur->src_ip &&
(tftp->srv_port == 0 ||
tftp->srv_port == ur->s_port)) {
uint16_t *xb = (uint16_t *)(ur+1);
if (ntohs(xb[0]) == TFTP_ACK &&
ntohs(xb[1]) == tftp->seq) {
tftp->srv_port = ur->s_port;
err = 0; /* All good! */
goto done;
} else if (ntohs(xb[1]) == TFTP_ERROR) {
goto done;
}
}
} while ((clock_t)(times(NULL) - start) < *timeout);
}
done:
lfree(ur);
lfree(uw);
return err;
}
static int be_tftp_write(struct backend *be)
{
static uint16_t local_port = 0x4000;
struct tftp_state tftp;
char buffer[512+4+6];
int nlen;
const union syslinux_derivative_info *sdi =
syslinux_derivative_info();
const char *data = be->outbuf;
size_t len = be->zbytes;
size_t chunk;
tftp.my_ip = sdi->pxe.myip;
tftp.my_port = htons(local_port++);
tftp.srv_gw = ((tftp.srv_ip ^ tftp.my_ip) & sdi->pxe.ipinfo->netmask)
? sdi->pxe.ipinfo->gateway : 0;
tftp.srv_port = 0;
tftp.seq = 0;
if (be->argv[1]) {
tftp.srv_ip = pxe_dns(be->argv[1]);
if (!tftp.srv_ip) {
printf("\nUnable to resolve hostname: %s\n", be->argv[1]);
return -1;
}
} else {
tftp.srv_ip = sdi->pxe.ipinfo->serverip;
if (!tftp.srv_ip) {
printf("\nNo server IP address\n");
return -1;
}
}
printf("server %u.%u.%u.%u... ",
((uint8_t *)&tftp.srv_ip)[0],
((uint8_t *)&tftp.srv_ip)[1],
((uint8_t *)&tftp.srv_ip)[2],
((uint8_t *)&tftp.srv_ip)[3]);
buffer[0] = 0;
buffer[1] = TFTP_WRQ;
nlen = strlcpy(buffer+2, be->argv[0], 512);
memcpy(buffer+3+nlen, "octet", 6);
if (send_ack_packet(&tftp, buffer, 2+nlen+1+6))
return -1;
do {
chunk = len >= 512 ? 512 : len;
buffer[1] = TFTP_DATA;
*((uint16_t *)(buffer+2)) = htons(++tftp.seq);
memcpy(buffer+4, data, chunk);
data += chunk;
len -= chunk;
if (send_ack_packet(&tftp, buffer, chunk+4))
return -1;
} while (chunk == 512);
return 0;
}
struct backend be_tftp = {
.name = "tftp",
.helpmsg = "filename [tftp_server]",
.minargs = 1,
.write = be_tftp_write,
};
