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
|
Index: busybox-1.4.2/networking/udhcp/packet.c
===================================================================
--- busybox-1.4.2.orig/networking/udhcp/packet.c 2007-06-04 13:21:32.289067984 +0200
+++ busybox-1.4.2/networking/udhcp/packet.c 2007-06-04 13:21:33.619865672 +0200
@@ -107,6 +107,10 @@
return ~sum;
}
+int udhcp_get_payload_len(struct dhcpMessage *payload)
+{
+ return sizeof(struct dhcpMessage) - MAX_OPTIONS_LEN + end_option(payload->options) + sizeof(payload->options[0]);
+}
/* Construct a ip/udp header for a packet, and specify the source and dest hardware address */
void BUG_sizeof_struct_udp_dhcp_packet_must_be_576(void);
@@ -118,6 +122,7 @@
int result;
struct sockaddr_ll dest;
struct udp_dhcp_packet packet;
+ int p_len = udhcp_get_payload_len(payload);
fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
if (fd < 0) {
@@ -127,6 +132,7 @@
memset(&dest, 0, sizeof(dest));
memset(&packet, 0, sizeof(packet));
+ memcpy(&(packet.data), payload, p_len);
dest.sll_family = AF_PACKET;
dest.sll_protocol = htons(ETH_P_IP);
@@ -144,12 +150,13 @@
packet.ip.daddr = dest_ip;
packet.udp.source = htons(source_port);
packet.udp.dest = htons(dest_port);
- packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage)); /* cheat on the psuedo-header */
+ p_len += sizeof(packet.udp);
+ packet.udp.len = htons(p_len);
packet.ip.tot_len = packet.udp.len;
- memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
- packet.udp.check = udhcp_checksum(&packet, sizeof(struct udp_dhcp_packet));
+ p_len += sizeof(packet.ip);
+ packet.udp.check = udhcp_checksum(&packet, p_len);
- packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
+ packet.ip.tot_len = htons(p_len);
packet.ip.ihl = sizeof(packet.ip) >> 2;
packet.ip.version = IPVERSION;
packet.ip.ttl = IPDEFTTL;
@@ -158,7 +165,7 @@
if (sizeof(struct udp_dhcp_packet) != 576)
BUG_sizeof_struct_udp_dhcp_packet_must_be_576();
- result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0,
+ result = sendto(fd, &packet, p_len, 0,
(struct sockaddr *) &dest, sizeof(dest));
if (result <= 0) {
bb_perror_msg("sendto");
@@ -205,7 +212,7 @@
return -1;
}
- result = write(fd, payload, sizeof(struct dhcpMessage));
+ result = write(fd, payload, udhcp_get_payload_len(payload));
close(fd);
return result;
}
Index: busybox-1.4.2/networking/udhcp/common.h
===================================================================
--- busybox-1.4.2.orig/networking/udhcp/common.h 2007-06-04 13:21:32.297066768 +0200
+++ busybox-1.4.2/networking/udhcp/common.h 2007-06-04 13:21:33.620865520 +0200
@@ -22,6 +22,8 @@
#include <netinet/udp.h>
#include <netinet/ip.h>
+#define MAX_OPTIONS_LEN 308
+
struct dhcpMessage {
uint8_t op;
uint8_t htype;
@@ -38,7 +40,7 @@
uint8_t sname[64];
uint8_t file[128];
uint32_t cookie;
- uint8_t options[308]; /* 312 - cookie */
+ uint8_t options[MAX_OPTIONS_LEN]; /* 312 - cookie */
};
struct udp_dhcp_packet {
|
