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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
#include "etherboot.h"
#include "in.h"
#include "nic.h"
#include "proto.h"
#include "tftp.h"
/* Utility function for tftp_block() */
static int await_tftp ( int ival, void *ptr __unused,
unsigned short ptype __unused, struct iphdr *ip,
struct udphdr *udp, struct tcphdr *tcp __unused ) {
if ( ! udp ) {
return 0;
}
if ( arptable[ARP_CLIENT].ipaddr.s_addr != ip->dest.s_addr )
return 0;
if ( ntohs ( udp->dest ) != ival )
return 0;
return 1;
}
/*
* Download a single block via TFTP. This function is non-static so
* that pxe_export.c can call it.
*
*/
int tftp_block ( struct tftpreq_info_t *request,
struct tftpblk_info_t *block ) {
static struct sockaddr_in server;
static unsigned short lport = 2000; /* local port */
struct tftp_t *rcvd = NULL;
static struct tftpreq_t xmit;
static unsigned short xmitlen = 0;
static unsigned short blockidx = 0; /* Last block received */
static unsigned short retry = 0; /* Retry attempts on last block */
static int blksize = 0;
unsigned short recvlen = 0;
/* If this is a new request (i.e. if name is set), fill in
* transmit block with RRQ and send it.
*/
if ( request ) {
rx_qdrain(); /* Flush receive queue */
xmit.opcode = htons(TFTP_RRQ);
xmitlen = (void*)&xmit.u.rrq - (void*)&xmit +
sprintf((char*)xmit.u.rrq, "%s%coctet%cblksize%c%d",
request->name, 0, 0, 0, request->blksize)
+ 1; /* null terminator */
blockidx = 0; /* Reset counters */
retry = 0;
blksize = TFTP_DEFAULTSIZE_PACKET;
lport++; /* Use new local port */
server = *(request->server);
if ( ! server.sin_port )
server.sin_port = TFTP_PORT;
if ( !udp_transmit(server.sin_addr.s_addr, lport,
server.sin_port, xmitlen, &xmit) )
return (0);
}
/* Exit if no transfer in progress */
if ( !blksize ) return (0);
/* Loop to wait until we get a packet we're interested in */
block->data = NULL; /* Used as flag */
while ( block->data == NULL ) {
long timeout = rfc2131_sleep_interval ( blockidx ? TFTP_REXMT :
TIMEOUT, retry );
if ( !await_reply(await_tftp, lport, NULL, timeout) ) {
/* No packet received */
if ( retry++ > MAX_TFTP_RETRIES ) break;
/* Retransmit last packet */
if ( !blockidx ) lport++; /* New lport if new RRQ */
if ( !udp_transmit(server.sin_addr.s_addr, lport,
server.sin_port, xmitlen, &xmit) )
return (0);
continue; /* Back to waiting for packet */
}
/* Packet has been received */
rcvd = (struct tftp_t *)&nic.packet[ETH_HLEN];
recvlen = ntohs(rcvd->udp.len) - sizeof(struct udphdr)
- sizeof(rcvd->opcode);
server.sin_port = ntohs(rcvd->udp.src);
retry = 0; /* Reset retry counter */
switch ( htons(rcvd->opcode) ) {
case TFTP_ERROR : {
printf ( "TFTP error %d (%s)\n",
ntohs(rcvd->u.err.errcode),
rcvd->u.err.errmsg );
return (0); /* abort */
}
case TFTP_OACK : {
const char *p = rcvd->u.oack.data;
const char *e = p + recvlen - 10; /* "blksize\0\d\0" */
*((char*)(p+recvlen-1)) = '\0'; /* Force final 0 */
if ( blockidx || !request ) break; /* Too late */
if ( recvlen <= TFTP_MAX_PACKET ) /* sanity */ {
/* Check for blksize option honoured */
while ( p < e ) {
if ( strcasecmp("blksize",p) == 0 &&
p[7] == '\0' ) {
blksize = strtoul(p+8,&p,10);
p++; /* skip null */
}
while ( *(p++) ) {};
}
}
if ( blksize < TFTP_DEFAULTSIZE_PACKET ||
blksize > request->blksize ) {
/* Incorrect blksize - error and abort */
xmit.opcode = htons(TFTP_ERROR);
xmit.u.err.errcode = 8;
xmitlen = (void*)&xmit.u.err.errmsg
- (void*)&xmit
+ sprintf((char*)xmit.u.err.errmsg,
"RFC1782 error")
+ 1;
udp_transmit(server.sin_addr.s_addr, lport,
server.sin_port, xmitlen, &xmit);
return (0);
}
} break;
case TFTP_DATA :
if ( ntohs(rcvd->u.data.block) != ( blockidx + 1 ) )
break; /* Re-ACK last block sent */
if ( recvlen > ( blksize+sizeof(rcvd->u.data.block) ) )
break; /* Too large; ignore */
block->data = rcvd->u.data.download;
block->block = ++blockidx;
block->len = recvlen - sizeof(rcvd->u.data.block);
block->eof = ( (unsigned short)block->len < blksize );
/* If EOF, zero blksize to indicate transfer done */
if ( block->eof ) blksize = 0;
break;
default: break; /* Do nothing */
}
/* Send ACK */
xmit.opcode = htons(TFTP_ACK);
xmit.u.ack.block = htons(blockidx);
xmitlen = TFTP_MIN_PACKET;
udp_transmit ( server.sin_addr.s_addr, lport, server.sin_port,
xmitlen, &xmit );
}
return ( block->data ? 1 : 0 );
}
/*
* Download a file via TFTP
*
*/
int tftp ( char *url __unused,
struct sockaddr_in *server,
char *file,
int ( * process ) ( unsigned char *data,
unsigned int blocknum,
unsigned int len, int eof ) ) {
struct tftpreq_info_t request_data = {
.server = server,
.name = file,
.blksize = TFTP_MAX_PACKET,
};
struct tftpreq_info_t *request = &request_data;
struct tftpblk_info_t block;
int rc;
while ( tftp_block ( request, &block ) ) {
request = NULL; /* Send request only once */
rc = process ( block.data, block.block, block.len, block.eof );
if ( rc <= 0 ) return ( rc );
}
return 0;
}
struct protocol tftp_protocol __default_protocol = {
"tftp", tftp
};
|
