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(that does not work with dumpleases) dumpleases: fix -a option. networking/udhcp/*: code shrink, more compact static leases struture, better comments, etc function old new delta find_free_or_expired_address - 147 +147 nobody_responds_to_arp - 84 +84 read_opt 781 830 +49 dumpleases_main 435 447 +12 send_ACK 229 232 +3 read_staticlease 90 93 +3 addStaticLease 60 61 +1 getIpByMac 46 43 -3 reservedIp 31 20 -11 keywords 304 288 -16 send_offer 428 403 -25 write_leases 225 193 -32 read_leases 184 143 -41 read_yn 64 - -64 find_address 191 - -191 ------------------------------------------------------------------------------ (add/remove: 2/2 grow/shrink: 5/6 up/down: 299/-383) Total: -84 bytes
165 lines
3.8 KiB
C
165 lines
3.8 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* leases.c -- tools to manage DHCP leases
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* Russ Dill <Russ.Dill@asu.edu> July 2001
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*/
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#include "common.h"
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#include "dhcpd.h"
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/* Find the oldest expired lease, NULL if there are no expired leases */
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static struct dhcpOfferedAddr *oldest_expired_lease(void)
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{
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struct dhcpOfferedAddr *oldest_lease = NULL;
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leasetime_t oldest_time = time(NULL);
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unsigned i;
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/* Unexpired leases have leases[i].expires >= current time
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* and therefore can't ever match */
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for (i = 0; i < server_config.max_leases; i++) {
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if (leases[i].expires < oldest_time) {
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oldest_time = leases[i].expires;
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oldest_lease = &(leases[i]);
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}
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}
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return oldest_lease;
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}
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/* Clear every lease out that chaddr OR yiaddr matches and is nonzero */
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static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)
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{
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unsigned i, j;
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for (j = 0; j < 16 && !chaddr[j]; j++)
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continue;
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for (i = 0; i < server_config.max_leases; i++) {
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if ((j != 16 && memcmp(leases[i].chaddr, chaddr, 16) == 0)
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|| (yiaddr && leases[i].yiaddr == yiaddr)
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) {
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memset(&(leases[i]), 0, sizeof(leases[i]));
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}
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}
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}
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/* Add a lease into the table, clearing out any old ones */
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struct dhcpOfferedAddr* FAST_FUNC add_lease(const uint8_t *chaddr, uint32_t yiaddr, leasetime_t leasetime)
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{
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struct dhcpOfferedAddr *oldest;
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/* clean out any old ones */
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clear_lease(chaddr, yiaddr);
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oldest = oldest_expired_lease();
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if (oldest) {
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memcpy(oldest->chaddr, chaddr, 16);
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oldest->yiaddr = yiaddr;
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oldest->expires = time(NULL) + leasetime;
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}
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return oldest;
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}
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/* True if a lease has expired */
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int FAST_FUNC lease_expired(struct dhcpOfferedAddr *lease)
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{
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return (lease->expires < (leasetime_t) time(NULL));
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}
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/* Find the first lease that matches chaddr, NULL if no match */
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struct dhcpOfferedAddr* FAST_FUNC find_lease_by_chaddr(const uint8_t *chaddr)
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{
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unsigned i;
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for (i = 0; i < server_config.max_leases; i++)
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if (!memcmp(leases[i].chaddr, chaddr, 16))
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return &(leases[i]);
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return NULL;
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}
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/* Find the first lease that matches yiaddr, NULL is no match */
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struct dhcpOfferedAddr* FAST_FUNC find_lease_by_yiaddr(uint32_t yiaddr)
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{
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unsigned i;
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for (i = 0; i < server_config.max_leases; i++)
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if (leases[i].yiaddr == yiaddr)
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return &(leases[i]);
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return NULL;
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}
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/* check is an IP is taken, if it is, add it to the lease table */
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static int nobody_responds_to_arp(uint32_t addr)
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{
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/* 16 zero bytes */
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static const uint8_t blank_chaddr[16] = { 0 };
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/* = { 0 } helps gcc to put it in rodata, not bss */
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struct in_addr temp;
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int r;
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r = arpping(addr, server_config.server, server_config.arp, server_config.interface);
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if (r)
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return r;
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temp.s_addr = addr;
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bb_info_msg("%s belongs to someone, reserving it for %u seconds",
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inet_ntoa(temp), (unsigned)server_config.conflict_time);
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add_lease(blank_chaddr, addr, server_config.conflict_time);
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return 0;
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}
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/* Find a new usable (we think) address. */
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uint32_t FAST_FUNC find_free_or_expired_address(void)
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{
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uint32_t addr;
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struct dhcpOfferedAddr *oldest_lease = NULL;
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addr = server_config.start_ip; /* addr is in host order here */
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for (; addr <= server_config.end_ip; addr++) {
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uint32_t net_addr;
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struct dhcpOfferedAddr *lease;
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/* ie, 192.168.55.0 */
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if ((addr & 0xff) == 0)
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continue;
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/* ie, 192.168.55.255 */
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if ((addr & 0xff) == 0xff)
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continue;
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net_addr = htonl(addr);
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/* addr has a static lease? */
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if (reservedIp(server_config.static_leases, net_addr))
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continue;
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lease = find_lease_by_yiaddr(net_addr);
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if (!lease) {
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if (nobody_responds_to_arp(net_addr))
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return net_addr;
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} else {
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if (!oldest_lease || lease->expires < oldest_lease->expires)
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oldest_lease = lease;
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}
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}
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if (oldest_lease && lease_expired(oldest_lease)
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&& nobody_responds_to_arp(oldest_lease->yiaddr)
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) {
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return oldest_lease->yiaddr;
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}
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return 0;
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}
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