2006-07-03 01:17:05 +05:30
|
|
|
/* vi: set sw=4 ts=4: */
|
2006-11-19 01:21:32 +05:30
|
|
|
|
2006-05-08 08:50:50 +05:30
|
|
|
#include <netinet/in.h>
|
2006-11-18 01:59:00 +05:30
|
|
|
#if (__GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION
|
2006-05-08 08:50:50 +05:30
|
|
|
#include <netpacket/packet.h>
|
|
|
|
#include <net/ethernet.h>
|
|
|
|
#else
|
|
|
|
#include <asm/types.h>
|
|
|
|
#include <linux/if_packet.h>
|
|
|
|
#include <linux/if_ether.h>
|
|
|
|
#endif
|
|
|
|
|
|
|
|
#include "common.h"
|
|
|
|
#include "dhcpd.h"
|
|
|
|
#include "options.h"
|
|
|
|
|
|
|
|
|
2006-05-28 06:36:36 +05:30
|
|
|
void udhcp_init_header(struct dhcpMessage *packet, char type)
|
2006-05-08 08:50:50 +05:30
|
|
|
{
|
|
|
|
memset(packet, 0, sizeof(struct dhcpMessage));
|
|
|
|
switch (type) {
|
|
|
|
case DHCPDISCOVER:
|
|
|
|
case DHCPREQUEST:
|
|
|
|
case DHCPRELEASE:
|
|
|
|
case DHCPINFORM:
|
|
|
|
packet->op = BOOTREQUEST;
|
|
|
|
break;
|
|
|
|
case DHCPOFFER:
|
|
|
|
case DHCPACK:
|
|
|
|
case DHCPNAK:
|
|
|
|
packet->op = BOOTREPLY;
|
|
|
|
}
|
|
|
|
packet->htype = ETH_10MB;
|
|
|
|
packet->hlen = ETH_10MB_LEN;
|
|
|
|
packet->cookie = htonl(DHCP_MAGIC);
|
|
|
|
packet->options[0] = DHCP_END;
|
|
|
|
add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/* read a packet from socket fd, return -1 on read error, -2 on packet error */
|
2006-05-28 06:36:36 +05:30
|
|
|
int udhcp_get_packet(struct dhcpMessage *packet, int fd)
|
2006-05-08 08:50:50 +05:30
|
|
|
{
|
|
|
|
static const char broken_vendors[][8] = {
|
|
|
|
"MSFT 98",
|
|
|
|
""
|
|
|
|
};
|
|
|
|
int bytes;
|
|
|
|
int i;
|
|
|
|
char unsigned *vendor;
|
|
|
|
|
|
|
|
memset(packet, 0, sizeof(struct dhcpMessage));
|
|
|
|
bytes = read(fd, packet, sizeof(struct dhcpMessage));
|
|
|
|
if (bytes < 0) {
|
2006-10-20 18:58:22 +05:30
|
|
|
DEBUG("cannot read on listening socket, ignoring");
|
2006-05-08 08:50:50 +05:30
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (ntohl(packet->cookie) != DHCP_MAGIC) {
|
2006-10-20 18:58:22 +05:30
|
|
|
bb_error_msg("received bogus message, ignoring");
|
2006-05-08 08:50:50 +05:30
|
|
|
return -2;
|
|
|
|
}
|
2006-09-07 00:06:50 +05:30
|
|
|
DEBUG("Received a packet");
|
2006-05-08 08:50:50 +05:30
|
|
|
|
|
|
|
if (packet->op == BOOTREQUEST && (vendor = get_option(packet, DHCP_VENDOR))) {
|
|
|
|
for (i = 0; broken_vendors[i][0]; i++) {
|
2006-11-19 01:21:32 +05:30
|
|
|
if (vendor[OPT_LEN - 2] == (uint8_t)strlen(broken_vendors[i])
|
|
|
|
&& !strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - 2])
|
|
|
|
) {
|
2006-09-07 00:06:50 +05:30
|
|
|
DEBUG("broken client (%s), forcing broadcast",
|
2006-05-08 08:50:50 +05:30
|
|
|
broken_vendors[i]);
|
|
|
|
packet->flags |= htons(BROADCAST_FLAG);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return bytes;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
2006-05-28 06:36:36 +05:30
|
|
|
uint16_t udhcp_checksum(void *addr, int count)
|
2006-05-08 08:50:50 +05:30
|
|
|
{
|
|
|
|
/* Compute Internet Checksum for "count" bytes
|
|
|
|
* beginning at location "addr".
|
|
|
|
*/
|
2006-07-01 18:38:46 +05:30
|
|
|
int32_t sum = 0;
|
2006-05-08 08:50:50 +05:30
|
|
|
uint16_t *source = (uint16_t *) addr;
|
|
|
|
|
|
|
|
while (count > 1) {
|
|
|
|
/* This is the inner loop */
|
|
|
|
sum += *source++;
|
|
|
|
count -= 2;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Add left-over byte, if any */
|
|
|
|
if (count > 0) {
|
|
|
|
/* Make sure that the left-over byte is added correctly both
|
|
|
|
* with little and big endian hosts */
|
|
|
|
uint16_t tmp = 0;
|
|
|
|
*(uint8_t *) (&tmp) = * (uint8_t *) source;
|
|
|
|
sum += tmp;
|
|
|
|
}
|
|
|
|
/* Fold 32-bit sum to 16 bits */
|
|
|
|
while (sum >> 16)
|
|
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
|
|
|
|
|
|
return ~sum;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/* Construct a ip/udp header for a packet, and specify the source and dest hardware address */
|
2006-11-20 06:43:09 +05:30
|
|
|
void BUG_sizeof_struct_udp_dhcp_packet_must_be_576(void);
|
2006-11-19 01:21:32 +05:30
|
|
|
int udhcp_raw_packet(struct dhcpMessage *payload,
|
|
|
|
uint32_t source_ip, int source_port,
|
|
|
|
uint32_t dest_ip, int dest_port, uint8_t *dest_arp, int ifindex)
|
2006-05-08 08:50:50 +05:30
|
|
|
{
|
|
|
|
int fd;
|
|
|
|
int result;
|
|
|
|
struct sockaddr_ll dest;
|
|
|
|
struct udp_dhcp_packet packet;
|
|
|
|
|
2006-11-19 01:21:32 +05:30
|
|
|
fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
|
|
|
|
if (fd < 0) {
|
2006-09-07 00:06:50 +05:30
|
|
|
bb_perror_msg("socket");
|
2006-05-08 08:50:50 +05:30
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
memset(&dest, 0, sizeof(dest));
|
|
|
|
memset(&packet, 0, sizeof(packet));
|
|
|
|
|
|
|
|
dest.sll_family = AF_PACKET;
|
|
|
|
dest.sll_protocol = htons(ETH_P_IP);
|
|
|
|
dest.sll_ifindex = ifindex;
|
|
|
|
dest.sll_halen = 6;
|
|
|
|
memcpy(dest.sll_addr, dest_arp, 6);
|
|
|
|
if (bind(fd, (struct sockaddr *)&dest, sizeof(struct sockaddr_ll)) < 0) {
|
2006-09-07 00:06:50 +05:30
|
|
|
bb_perror_msg("bind");
|
2006-05-08 08:50:50 +05:30
|
|
|
close(fd);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
packet.ip.protocol = IPPROTO_UDP;
|
|
|
|
packet.ip.saddr = source_ip;
|
|
|
|
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 */
|
|
|
|
packet.ip.tot_len = packet.udp.len;
|
|
|
|
memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
|
2006-05-28 06:36:36 +05:30
|
|
|
packet.udp.check = udhcp_checksum(&packet, sizeof(struct udp_dhcp_packet));
|
2006-05-08 08:50:50 +05:30
|
|
|
|
|
|
|
packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
|
|
|
|
packet.ip.ihl = sizeof(packet.ip) >> 2;
|
|
|
|
packet.ip.version = IPVERSION;
|
|
|
|
packet.ip.ttl = IPDEFTTL;
|
2006-05-28 06:36:36 +05:30
|
|
|
packet.ip.check = udhcp_checksum(&(packet.ip), sizeof(packet.ip));
|
2006-05-08 08:50:50 +05:30
|
|
|
|
2006-11-20 06:43:09 +05:30
|
|
|
if (sizeof(struct udp_dhcp_packet) != 576)
|
|
|
|
BUG_sizeof_struct_udp_dhcp_packet_must_be_576();
|
|
|
|
|
2006-11-19 01:21:32 +05:30
|
|
|
result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0,
|
|
|
|
(struct sockaddr *) &dest, sizeof(dest));
|
2006-05-08 08:50:50 +05:30
|
|
|
if (result <= 0) {
|
2006-09-07 00:06:50 +05:30
|
|
|
bb_perror_msg("sendto");
|
2006-05-08 08:50:50 +05:30
|
|
|
}
|
|
|
|
close(fd);
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/* Let the kernel do all the work for packet generation */
|
2006-11-19 01:21:32 +05:30
|
|
|
int udhcp_kernel_packet(struct dhcpMessage *payload,
|
|
|
|
uint32_t source_ip, int source_port,
|
|
|
|
uint32_t dest_ip, int dest_port)
|
2006-05-08 08:50:50 +05:30
|
|
|
{
|
|
|
|
int n = 1;
|
|
|
|
int fd, result;
|
|
|
|
struct sockaddr_in client;
|
|
|
|
|
2006-11-19 01:21:32 +05:30
|
|
|
fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
|
|
|
|
if (fd < 0)
|
2006-05-08 08:50:50 +05:30
|
|
|
return -1;
|
|
|
|
|
|
|
|
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == -1) {
|
|
|
|
close(fd);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
memset(&client, 0, sizeof(client));
|
|
|
|
client.sin_family = AF_INET;
|
|
|
|
client.sin_port = htons(source_port);
|
|
|
|
client.sin_addr.s_addr = source_ip;
|
|
|
|
|
|
|
|
if (bind(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1) {
|
|
|
|
close(fd);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
memset(&client, 0, sizeof(client));
|
|
|
|
client.sin_family = AF_INET;
|
|
|
|
client.sin_port = htons(dest_port);
|
|
|
|
client.sin_addr.s_addr = dest_ip;
|
|
|
|
|
|
|
|
if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1) {
|
|
|
|
close(fd);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
result = write(fd, payload, sizeof(struct dhcpMessage));
|
|
|
|
close(fd);
|
|
|
|
return result;
|
|
|
|
}
|