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/*
* TFTP data output backend
*/
#include <string.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,
};
static uint16_t local_port = 0x4000;
static int send_ack_packet(struct backend *be, const void *pkt, size_t len)
{
com32sys_t ireg, oreg;
t_PXENV_UDP_WRITE *uw = __com32.cs_bounce;
t_PXENV_UDP_READ *ur = __com32.cs_bounce;
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;
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 = be->tftp.srv_ip;
uw->src_port = be->tftp.my_port;
uw->dst_port = be->tftp.srv_port ? be->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 = be->tftp.srv_ip;
ur->dest_ip = be->tftp.my_ip;
ur->s_port = be->tftp.srv_port;
ur->d_port = be->tftp.my_port;
ur->buffer_size = __com32.cs_bounce_size - sizeof *ur;
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 &&
be->tftp.srv_ip == ur->src_ip &&
(be->tftp.srv_port == 0 ||
be->tftp.srv_port == ur->s_port)) {
uint16_t *xb = (uint16_t *)(ur+1);
if (ntohs(xb[0]) == TFTP_ACK &&
ntohs(xb[1]) == be->tftp.seq) {
be->tftp.srv_port = ur->s_port;
return 0; /* All good! */
} else if (ntohs(xb[1]) == TFTP_ERROR) {
return -1; /* All bad! */
}
}
} while ((clock_t)(times(NULL) - start) < *timeout);
}
return -1; /* No success... */
}
static int be_tftp_open(struct backend *be, const char *argv[])
{
char buffer[512+4+6];
int nlen;
const union syslinux_derivative_info *sdi =
syslinux_derivative_info();
be->tftp.my_ip = sdi->pxe.myip;
be->tftp.my_port = htons(local_port++);
be->tftp.srv_ip = pxe_dns(argv[1]);
be->tftp.srv_port = 0;
be->tftp.seq = 0;
buffer[0] = 0;
buffer[1] = TFTP_WRQ;
nlen = strlcpy(buffer+2, argv[0], 512);
memcpy(buffer+3+nlen, "octet", 6);
return send_ack_packet(be, buffer, 2+nlen+1+6);
}
static int be_tftp_write(struct backend *be, const char *buf, size_t len)
{
char buffer[512+4];
buffer[0] = 0;
buffer[1] = TFTP_DATA;
*((uint16_t *)(buffer+2)) = htons(++be->tftp.seq);
memcpy(buffer+4, buf, len);
return send_ack_packet(be, buffer, len+4);
}
struct backend be_tftp = {
.name = "tftp",
.blocksize = 512,
.open = be_tftp_open,
.write = be_tftp_write,
};
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