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https://github.com/topjohnwu/ndk-busybox.git
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fbd2918f5c
a few global variables reduced to smallints function old new delta add_lease 75 227 +152 static.blank_chaddr - 16 +16 MAC_BCAST_ADDR - 6 +6 sockfd 4 8 +4 udhcp_run_script 1153 1155 +2 state 8 5 -3 listen_mode 4 1 -3 perform_release 152 148 -4 fd 8 4 -4 blank_chaddr 16 - -16 udhcpc_main 2518 2497 -21 .rodata 131864 131832 -32 oldest_expired_lease 61 - -61 clear_lease 127 - -127 ------------------------------------------------------------------------------ (add/remove: 2/3 grow/shrink: 3/6 up/down: 180/-271) Total: -91 bytes
148 lines
3.5 KiB
C
148 lines
3.5 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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#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 = NULL;
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unsigned long oldest_lease = time(0);
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unsigned i;
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for (i = 0; i < server_config.max_leases; i++)
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if (oldest_lease > leases[i].expires) {
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oldest_lease = leases[i].expires;
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oldest = &(leases[i]);
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}
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return oldest;
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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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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(struct dhcpOfferedAddr));
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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 *add_lease(const uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)
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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(0) + lease;
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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 lease_expired(struct dhcpOfferedAddr *lease)
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{
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return (lease->expires < (unsigned long) time(0));
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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 *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 *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 check_ip(uint32_t addr)
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{
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static const uint8_t blank_chaddr[16]; /* 16 zero bytes */
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struct in_addr temp;
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if (arpping(addr, server_config.server, server_config.arp, server_config.interface) == 0) {
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temp.s_addr = addr;
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bb_info_msg("%s belongs to someone, reserving it for %ld seconds",
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inet_ntoa(temp), server_config.conflict_time);
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add_lease(blank_chaddr, addr, server_config.conflict_time);
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return 1;
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}
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return 0;
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}
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/* find an assignable address, it check_expired is true, we check all the expired leases as well.
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* Maybe this should try expired leases by age... */
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uint32_t find_address(int check_expired)
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{
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uint32_t addr, ret;
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struct dhcpOfferedAddr *lease = NULL;
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addr = ntohl(server_config.start); /* addr is in host order here */
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for (;addr <= ntohl(server_config.end); addr++) {
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/* ie, 192.168.55.0 */
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if (!(addr & 0xFF)) continue;
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/* ie, 192.168.55.255 */
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if ((addr & 0xFF) == 0xFF) continue;
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/* Only do if it isn't assigned as a static lease */
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if (!reservedIp(server_config.static_leases, htonl(addr))) {
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/* lease is not taken */
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ret = htonl(addr);
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lease = find_lease_by_yiaddr(ret);
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/* no lease or it expired and we are checking for expired leases */
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if ((!lease || (check_expired && lease_expired(lease)))
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&& /* and it isn't on the network */ !check_ip(ret)
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) {
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return ret;
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}
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}
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}
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return 0;
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}
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