aboutsummaryrefslogtreecommitdiffstats
path: root/com32/sysdump/be_tftp.c
blob: e9a9887302eb7794ef3286c23f9285a3dc68da5c (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
/*
 * 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[], size_t len)
{
    char buffer[512+4+6];
    int nlen;
    const union syslinux_derivative_info *sdi =
	syslinux_derivative_info();

    (void)len;

    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",
    .helpmsg    = "filename tftp_server",
    .minargs    = 2,
    .blocksize	= 512,
    .flags      = 0,
    .open       = be_tftp_open,
    .write      = be_tftp_write,
};