Move dhcp packet reply code to packet.c.
This commit is contained in:
Nicholas J. Kain
parent
9390e131b6
commit
adcc4bdd3d
@ -1,6 +1,9 @@
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#ifndef DHCPC_H_
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#define DHCPC_H_
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#define NUMPACKETS 3 /* number of packets to send before delay */
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#define RETRY_DELAY 30 /* time in seconds to delay after sending NUMPACKETS */
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enum {
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DS_NULL = 0,
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DS_INIT_SELECTING,
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140
ndhc/ndhc.c
140
ndhc/ndhc.c
@ -59,8 +59,6 @@
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#include "io.h"
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#define VERSION "1.0"
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#define NUMPACKETS 3 /* number of packets to send before delay */
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#define RETRY_DELAY 30 /* time in seconds to delay after sending NUMPACKETS */
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struct client_state_t cs = {
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.dhcpState = DS_INIT_SELECTING,
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@ -150,7 +148,7 @@ static void show_usage(void)
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}
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/* Switch listen socket between raw (if-bound), kernel (ip-bound), and none */
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static void change_listen_mode(int new_mode)
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void change_listen_mode(int new_mode)
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{
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log_line("entering %s listen mode",
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new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
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@ -260,6 +258,19 @@ static struct arpMsg arpreply;
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static int arpreply_offset;
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static struct dhcpMessage arp_dhcp_packet;
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void arp_check(struct dhcpMessage *packet)
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{
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cs.arpPrevState = cs.dhcpState;
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cs.dhcpState = DS_ARP_CHECK;
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memcpy(&arp_dhcp_packet, packet, sizeof (struct dhcpMessage));
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cs.arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0,
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client_config.arp, client_config.interface);
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epoll_add(cs.arpFd);
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cs.timeout = 2000;
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memset(&arpreply, 0, sizeof arpreply);
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arpreply_offset = 0;
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}
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static void arp_failed(void)
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{
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log_line("Offered address is in use: declining.");
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@ -426,127 +437,6 @@ static void handle_timeout(void)
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}
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}
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static void init_selecting_packet(struct dhcpMessage *packet,
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unsigned char *message)
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{
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unsigned char *temp = NULL;
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/* Must be a DHCPOFFER to one of our xid's */
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if (*message == DHCPOFFER) {
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if ((temp = get_option(packet, DHCP_SERVER_ID))) {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&cs.serverAddr, temp, 4);
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cs.xid = packet->xid;
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cs.requestedIP = packet->yiaddr;
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/* enter requesting state */
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cs.dhcpState = DS_REQUESTING;
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cs.timeout = 0;
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cs.packetNum = 0;
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} else {
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log_line("No server ID in message");
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}
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}
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}
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static void dhcp_ack_or_nak_packet(struct dhcpMessage *packet,
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unsigned char *message)
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{
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unsigned char *temp = NULL;
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if (*message == DHCPACK) {
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if (!(temp = get_option(packet, DHCP_LEASE_TIME))) {
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log_line("No lease time received, assuming 1h.");
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cs.lease = 60 * 60;
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} else {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&cs.lease, temp, 4);
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cs.lease = ntohl(cs.lease);
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/* Enforce upper and lower bounds on lease. */
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cs.lease &= 0x0fffffff;
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if (cs.lease < RETRY_DELAY)
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cs.lease = RETRY_DELAY;
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}
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cs.arpPrevState = cs.dhcpState;
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cs.dhcpState = DS_ARP_CHECK;
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memcpy(&arp_dhcp_packet, packet, sizeof (struct dhcpMessage));
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cs.arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0,
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client_config.arp, client_config.interface);
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epoll_add(cs.arpFd);
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cs.timeout = 2000;
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memset(&arpreply, 0, sizeof arpreply);
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arpreply_offset = 0;
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// Can transition to DS_BOUND or DS_INIT_SELECTING.
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} else if (*message == DHCPNAK) {
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/* return to init state */
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log_line("Received DHCP NAK.");
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run_script(packet, SCRIPT_NAK);
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if (cs.dhcpState != DS_REQUESTING)
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run_script(NULL, SCRIPT_DECONFIG);
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cs.dhcpState = DS_INIT_SELECTING;
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cs.timeout = 0;
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cs.requestedIP = 0;
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cs.packetNum = 0;
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change_listen_mode(LM_RAW);
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// XXX: this isn't rfc compliant: should be exp backoff
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sleep(3); /* avoid excessive network traffic */
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}
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}
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static void handle_packet(void)
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{
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unsigned char *message = NULL;
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int len;
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struct dhcpMessage packet;
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if (cs.listenMode == LM_KERNEL)
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len = get_packet(&packet, cs.listenFd);
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else if (cs.listenMode == LM_RAW)
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len = get_raw_packet(&packet, cs.listenFd);
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else /* LM_NONE */
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return;
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if (len == -1 && errno != EINTR) {
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log_error("reopening socket.");
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change_listen_mode(cs.listenMode); /* just close and reopen */
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}
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if (len < 0)
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return;
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if (packet.xid != cs.xid) {
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log_line("Ignoring XID %lx (our xid is %lx).",
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(uint32_t) packet.xid, cs.xid);
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return;
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}
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if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
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log_line("couldnt get option from packet -- ignoring");
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return;
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}
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switch (cs.dhcpState) {
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case DS_INIT_SELECTING:
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init_selecting_packet(&packet, message);
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break;
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case DS_ARP_CHECK:
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/* We ignore dhcp packets for now. This state will
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* be changed by the callback for arp ping.
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*/
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break;
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case DS_RENEW_REQUESTED:
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case DS_REQUESTING:
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case DS_RENEWING:
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case DS_REBINDING:
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dhcp_ack_or_nak_packet(&packet, message);
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break;
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case DS_BOUND:
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case DS_RELEASED:
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default:
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break;
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}
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}
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typedef uint32_t aliased_uint32_t __attribute__((__may_alias__));
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static void handle_arp_response(void)
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{
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@ -655,7 +545,7 @@ static void do_work(void)
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if (fd == cs.signalFd)
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signal_dispatch();
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else if (fd == cs.listenFd)
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handle_packet();
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handle_packet(&cs);
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else if (fd == cs.arpFd)
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handle_arp_response();
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else
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125
ndhc/packet.c
125
ndhc/packet.c
@ -10,6 +10,8 @@
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#include <errno.h>
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#include "packet.h"
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#include "clientpacket.h"
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#include "script.h"
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#include "log.h"
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#include "io.h"
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#include "dhcpd.h"
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@ -65,8 +67,8 @@ uint16_t checksum(void *addr, int count)
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/* Constuct a ip/udp header for a packet, and specify the source and dest
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* hardware address */
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int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
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int source_port, uint32_t dest_ip, int dest_port,
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unsigned char *dest_arp, int ifindex)
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int source_port, uint32_t dest_ip, int dest_port,
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unsigned char *dest_arp, int ifindex)
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{
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struct sockaddr_ll dest;
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struct ip_udp_dhcp_packet packet;
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@ -169,3 +171,122 @@ int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
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out:
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return result;
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}
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static void init_selecting_packet(struct client_state_t *cs,
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struct dhcpMessage *packet,
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unsigned char *message)
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{
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unsigned char *temp = NULL;
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/* Must be a DHCPOFFER to one of our xid's */
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if (*message == DHCPOFFER) {
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if ((temp = get_option(packet, DHCP_SERVER_ID))) {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&cs->serverAddr, temp, 4);
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cs->xid = packet->xid;
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cs->requestedIP = packet->yiaddr;
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/* enter requesting state */
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cs->dhcpState = DS_REQUESTING;
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cs->timeout = 0;
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cs->packetNum = 0;
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} else {
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log_line("No server ID in message");
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}
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}
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}
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// from ndhc.c
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void change_listen_mode(int new_mode);
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void arp_check(struct dhcpMessage *packet);
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static void dhcp_ack_or_nak_packet(struct client_state_t *cs,
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struct dhcpMessage *packet,
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unsigned char *message)
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{
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unsigned char *temp = NULL;
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if (*message == DHCPACK) {
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if (!(temp = get_option(packet, DHCP_LEASE_TIME))) {
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log_line("No lease time received, assuming 1h.");
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cs->lease = 60 * 60;
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} else {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&cs->lease, temp, 4);
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cs->lease = ntohl(cs->lease);
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/* Enforce upper and lower bounds on lease. */
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cs->lease &= 0x0fffffff;
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if (cs->lease < RETRY_DELAY)
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cs->lease = RETRY_DELAY;
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}
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arp_check(packet);
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// Can transition from DS_ARP_CHECK to DS_BOUND or DS_INIT_SELECTING.
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} else if (*message == DHCPNAK) {
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/* return to init state */
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log_line("Received DHCP NAK.");
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run_script(packet, SCRIPT_NAK);
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if (cs->dhcpState != DS_REQUESTING)
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run_script(NULL, SCRIPT_DECONFIG);
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cs->dhcpState = DS_INIT_SELECTING;
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cs->timeout = 0;
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cs->requestedIP = 0;
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cs->packetNum = 0;
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change_listen_mode(LM_RAW);
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// XXX: this isn't rfc compliant: should be exp backoff
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sleep(3); /* avoid excessive network traffic */
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}
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}
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void handle_packet(struct client_state_t *cs)
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{
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unsigned char *message = NULL;
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int len;
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struct dhcpMessage packet;
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if (cs->listenMode == LM_KERNEL)
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len = get_packet(&packet, cs->listenFd);
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else if (cs->listenMode == LM_RAW)
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len = get_raw_packet(&packet, cs->listenFd);
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else /* LM_NONE */
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return;
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if (len == -1 && errno != EINTR) {
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log_error("reopening socket.");
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change_listen_mode(cs->listenMode); /* just close and reopen */
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}
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if (len < 0)
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return;
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if (packet.xid != cs->xid) {
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log_line("Ignoring XID %lx (our xid is %lx).",
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(uint32_t) packet.xid, cs->xid);
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return;
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}
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if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
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log_line("couldnt get option from packet -- ignoring");
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return;
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}
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switch (cs->dhcpState) {
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case DS_INIT_SELECTING:
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init_selecting_packet(cs, &packet, message);
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break;
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case DS_ARP_CHECK:
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/* We ignore dhcp packets for now. This state will
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* be changed by the callback for arp ping.
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*/
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break;
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case DS_RENEW_REQUESTED:
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case DS_REQUESTING:
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case DS_RENEWING:
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case DS_REBINDING:
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dhcp_ack_or_nak_packet(cs, &packet, message);
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break;
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case DS_BOUND:
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case DS_RELEASED:
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default:
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break;
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}
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}
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@ -4,6 +4,8 @@
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#include <netinet/udp.h>
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#include <netinet/ip.h>
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#include "config.h"
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struct dhcpMessage {
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uint8_t op;
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uint8_t htype;
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@ -52,5 +54,5 @@ int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
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unsigned char *dest_arp, int ifindex);
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int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
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int source_port, uint32_t dest_ip, int dest_port);
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void handle_packet(struct client_state_t *cs);
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#endif
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