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Move dhcp packet reply code to packet.c.

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This commit is contained in:
Nicholas J. Kain
2010-12-24 08:55:59 -05:00
parent 9390e131b6
commit adcc4bdd3d
4 changed files with 144 additions and 128 deletions
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125
ndhc/packet.c
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@@ -10,6 +10,8 @@
#include <errno.h>
#include "packet.h"
#include "clientpacket.h"
#include "script.h"
#include "log.h"
#include "io.h"
#include "dhcpd.h"
@@ -65,8 +67,8 @@ uint16_t checksum(void *addr, int count)
/* Constuct a ip/udp header for a packet, and specify the source and dest
* hardware address */
int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
int source_port, uint32_t dest_ip, int dest_port,
unsigned char *dest_arp, int ifindex)
int source_port, uint32_t dest_ip, int dest_port,
unsigned char *dest_arp, int ifindex)
{
struct sockaddr_ll dest;
struct ip_udp_dhcp_packet packet;
@@ -169,3 +171,122 @@ int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
out:
return result;
}
static void init_selecting_packet(struct client_state_t *cs,
struct dhcpMessage *packet,
unsigned char *message)
{
unsigned char *temp = NULL;
/* Must be a DHCPOFFER to one of our xid's */
if (*message == DHCPOFFER) {
if ((temp = get_option(packet, DHCP_SERVER_ID))) {
/* Memcpy to a temp buffer to force alignment */
memcpy(&cs->serverAddr, temp, 4);
cs->xid = packet->xid;
cs->requestedIP = packet->yiaddr;
/* enter requesting state */
cs->dhcpState = DS_REQUESTING;
cs->timeout = 0;
cs->packetNum = 0;
} else {
log_line("No server ID in message");
}
}
}
// from ndhc.c
void change_listen_mode(int new_mode);
void arp_check(struct dhcpMessage *packet);
static void dhcp_ack_or_nak_packet(struct client_state_t *cs,
struct dhcpMessage *packet,
unsigned char *message)
{
unsigned char *temp = NULL;
if (*message == DHCPACK) {
if (!(temp = get_option(packet, DHCP_LEASE_TIME))) {
log_line("No lease time received, assuming 1h.");
cs->lease = 60 * 60;
} else {
/* Memcpy to a temp buffer to force alignment */
memcpy(&cs->lease, temp, 4);
cs->lease = ntohl(cs->lease);
/* Enforce upper and lower bounds on lease. */
cs->lease &= 0x0fffffff;
if (cs->lease < RETRY_DELAY)
cs->lease = RETRY_DELAY;
}
arp_check(packet);
// Can transition from DS_ARP_CHECK to DS_BOUND or DS_INIT_SELECTING.
} else if (*message == DHCPNAK) {
/* return to init state */
log_line("Received DHCP NAK.");
run_script(packet, SCRIPT_NAK);
if (cs->dhcpState != DS_REQUESTING)
run_script(NULL, SCRIPT_DECONFIG);
cs->dhcpState = DS_INIT_SELECTING;
cs->timeout = 0;
cs->requestedIP = 0;
cs->packetNum = 0;
change_listen_mode(LM_RAW);
// XXX: this isn't rfc compliant: should be exp backoff
sleep(3); /* avoid excessive network traffic */
}
}
void handle_packet(struct client_state_t *cs)
{
unsigned char *message = NULL;
int len;
struct dhcpMessage packet;
if (cs->listenMode == LM_KERNEL)
len = get_packet(&packet, cs->listenFd);
else if (cs->listenMode == LM_RAW)
len = get_raw_packet(&packet, cs->listenFd);
else /* LM_NONE */
return;
if (len == -1 && errno != EINTR) {
log_error("reopening socket.");
change_listen_mode(cs->listenMode); /* just close and reopen */
}
if (len < 0)
return;
if (packet.xid != cs->xid) {
log_line("Ignoring XID %lx (our xid is %lx).",
(uint32_t) packet.xid, cs->xid);
return;
}
if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
log_line("couldnt get option from packet -- ignoring");
return;
}
switch (cs->dhcpState) {
case DS_INIT_SELECTING:
init_selecting_packet(cs, &packet, message);
break;
case DS_ARP_CHECK:
/* We ignore dhcp packets for now. This state will
* be changed by the callback for arp ping.
*/
break;
case DS_RENEW_REQUESTED:
case DS_REQUESTING:
case DS_RENEWING:
case DS_REBINDING:
dhcp_ack_or_nak_packet(cs, &packet, message);
break;
case DS_BOUND:
case DS_RELEASED:
default:
break;
}
}