2 * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
18 #include <sys/socket.h>
28 struct ether_header eth
;
33 uint8_t op
, htype
, hlen
, hops
;
36 struct in_addr ciaddr
, yiaddr
, siaddr
, giaddr
;
37 unsigned char chaddr
[16];
38 unsigned char sname
[64];
39 unsigned char file
[128];
43 chksum(uint16_t sum
, const uint8_t *data
, uint16_t len
)
48 last
= data
+ len
- 1;
51 t
= (data
[0] << 8) + data
[1];
59 t
= (data
[0] << 8) + 0;
68 bool relayd_handle_dhcp_packet(struct relayd_interface
*rif
, void *data
, int len
, bool forward
)
70 struct ip_packet
*pkt
= data
;
72 struct dhcp_header
*dhcp
;
76 if (pkt
->eth
.ether_type
!= htons(ETH_P_IP
))
79 if (pkt
->iph
.version
!= 4)
82 if (pkt
->iph
.protocol
!= IPPROTO_UDP
)
85 udp
= (void *) ((char *) &pkt
->iph
+ (pkt
->iph
.ihl
<< 2));
86 dhcp
= (void *) (udp
+ 1);
88 udplen
= ntohs(udp
->len
);
89 if (udplen
> len
- ((char *) udp
- (char *) data
))
92 if (udp
->dest
!= htons(67) && udp
->source
!= htons(67))
95 if (dhcp
->op
!= 1 && dhcp
->op
!= 2)
102 relayd_refresh_host(rif
, pkt
->eth
.ether_shost
, (void *) &pkt
->iph
.saddr
);
104 DPRINTF(2, "%s: handling DHCP %s\n", rif
->ifname
, (dhcp
->op
== 1 ? "request" : "response"));
106 dhcp
->flags
|= htons(DHCP_FLAG_BROADCAST
);
109 sum
= udplen
+ IPPROTO_UDP
;
110 sum
= chksum(sum
, (void *) &pkt
->iph
.saddr
, 8);
111 sum
= chksum(sum
, (void *) udp
, udplen
);
115 udp
->check
= htons(~sum
);
117 relayd_forward_bcast_packet(rif
, data
, len
);