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
|
/*
* server/query.c
*/
#include <arpa/inet.h>
#include <inttypes.h>
#include <byteswap.h>
#include <syslog.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "dnbd2.h"
#include "query.h"
#include "tree.h"
#include "file.h"
int handle_query(dnbd2_data_request_t *request,
dnbd2_data_reply_t *reply,
void **tree)
{
int fd, i;
node_t node1;
node_t *node2;
dataset_t ds;
off_t size, pos;
uint16_t cmd;
/* Fetch the right fd for this vid/rid pair. */
ds.vid = ntohs(request->vid);
ds.rid = ntohs(request->rid);
node1.ds = &ds;
node2 = tree_find(&node1, tree);
if (!node2)
return -1;
fd = node2->fd;
cmd = ntohs(request->cmd);
switch (cmd) {
case CMD_GET_BLOCK:
reply->num = request->num;
pos = ntohll(request->num);
file_read(fd, reply->payload.data, DNBD2_BLOCK_SIZE, pos);
break;
case CMD_GET_SIZE:
if (file_getsize(fd, &size) == -1)
return -1;
reply->num = htonll(size);
break;
case CMD_GET_SERVERS:
/* Fetch a random block to deliver a more realistic RTT. */
pos = 0;
if (!file_getsize(fd, &size))
pos = (off_t) (size * (rand() / (RAND_MAX + 1.0)));
file_read(fd, reply->payload.data, DNBD2_BLOCK_SIZE, pos);
reply->num = htonll(node2->servers);
for (i=0 ; i<node2->servers ; i++) {
memcpy(&reply->payload.server[i],
&node2->server[i],
sizeof(dnbd2_server_t));
}
break;
}
reply->cmd = request->cmd;
reply->time = request->time;
reply->vid = request->vid;
reply->rid = request->rid;
return 0;
}
|
