aboutsummaryrefslogtreecommitdiffstats
path: root/com32/sysdump/be_tftp.c
blob: 07fdb0842b76dcedc6efab3351410ebd6b0dacdf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 * 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,
};

struct tftp_state {
    uint32_t my_ip;
    uint32_t srv_ip;
    uint16_t my_port;
    uint16_t srv_port;
    uint16_t seq;
};

static int send_ack_packet(struct tftp_state *tftp,
			   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 = tftp->srv_ip;
	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 = __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 &&
		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;
		    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_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_ip   = pxe_dns(be->argv[1]);
    tftp.srv_port = 0;
    tftp.seq      = 0;

    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    = 2,
    .write      = be_tftp_write,
};