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    Contents of /trunk/mkinitrd-magellan/busybox/networking/udhcp/leases.c

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    Revision 532 - (show annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 8 months ago) by niro
    File MIME type: text/plain
    File size: 3546 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    1 /* vi: set sw=4 ts=4: */
    2 /*
    3 * leases.c -- tools to manage DHCP leases
    4 * Russ Dill <Russ.Dill@asu.edu> July 2001
    5 */
    6
    7 #include "common.h"
    8 #include "dhcpd.h"
    9
    10
    11 uint8_t blank_chaddr[] = {[0 ... 15] = 0};
    12
    13 /* clear every lease out that chaddr OR yiaddr matches and is nonzero */
    14 void clear_lease(uint8_t *chaddr, uint32_t yiaddr)
    15 {
    16 unsigned int i, j;
    17
    18 for (j = 0; j < 16 && !chaddr[j]; j++);
    19
    20 for (i = 0; i < server_config.max_leases; i++)
    21 if ((j != 16 && !memcmp(leases[i].chaddr, chaddr, 16)) ||
    22 (yiaddr && leases[i].yiaddr == yiaddr)) {
    23 memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr));
    24 }
    25 }
    26
    27
    28 /* add a lease into the table, clearing out any old ones */
    29 struct dhcpOfferedAddr *add_lease(uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)
    30 {
    31 struct dhcpOfferedAddr *oldest;
    32
    33 /* clean out any old ones */
    34 clear_lease(chaddr, yiaddr);
    35
    36 oldest = oldest_expired_lease();
    37
    38 if (oldest) {
    39 memcpy(oldest->chaddr, chaddr, 16);
    40 oldest->yiaddr = yiaddr;
    41 oldest->expires = time(0) + lease;
    42 }
    43
    44 return oldest;
    45 }
    46
    47
    48 /* true if a lease has expired */
    49 int lease_expired(struct dhcpOfferedAddr *lease)
    50 {
    51 return (lease->expires < (unsigned long) time(0));
    52 }
    53
    54
    55 /* Find the oldest expired lease, NULL if there are no expired leases */
    56 struct dhcpOfferedAddr *oldest_expired_lease(void)
    57 {
    58 struct dhcpOfferedAddr *oldest = NULL;
    59 unsigned long oldest_lease = time(0);
    60 unsigned int i;
    61
    62
    63 for (i = 0; i < server_config.max_leases; i++)
    64 if (oldest_lease > leases[i].expires) {
    65 oldest_lease = leases[i].expires;
    66 oldest = &(leases[i]);
    67 }
    68 return oldest;
    69
    70 }
    71
    72
    73 /* Find the first lease that matches chaddr, NULL if no match */
    74 struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr)
    75 {
    76 unsigned int i;
    77
    78 for (i = 0; i < server_config.max_leases; i++)
    79 if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]);
    80
    81 return NULL;
    82 }
    83
    84
    85 /* Find the first lease that matches yiaddr, NULL is no match */
    86 struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr)
    87 {
    88 unsigned int i;
    89
    90 for (i = 0; i < server_config.max_leases; i++)
    91 if (leases[i].yiaddr == yiaddr) return &(leases[i]);
    92
    93 return NULL;
    94 }
    95
    96
    97 /* check is an IP is taken, if it is, add it to the lease table */
    98 static int check_ip(uint32_t addr)
    99 {
    100 struct in_addr temp;
    101
    102 if (arpping(addr, server_config.server, server_config.arp, server_config.interface) == 0) {
    103 temp.s_addr = addr;
    104 bb_info_msg("%s belongs to someone, reserving it for %ld seconds",
    105 inet_ntoa(temp), server_config.conflict_time);
    106 add_lease(blank_chaddr, addr, server_config.conflict_time);
    107 return 1;
    108 } else return 0;
    109 }
    110
    111
    112 /* find an assignable address, it check_expired is true, we check all the expired leases as well.
    113 * Maybe this should try expired leases by age... */
    114 uint32_t find_address(int check_expired)
    115 {
    116 uint32_t addr, ret;
    117 struct dhcpOfferedAddr *lease = NULL;
    118
    119 addr = ntohl(server_config.start); /* addr is in host order here */
    120 for (;addr <= ntohl(server_config.end); addr++) {
    121
    122 /* ie, 192.168.55.0 */
    123 if (!(addr & 0xFF)) continue;
    124
    125 /* ie, 192.168.55.255 */
    126 if ((addr & 0xFF) == 0xFF) continue;
    127
    128 /* Only do if it isn't an assigned as a static lease */
    129 if (!reservedIp(server_config.static_leases, htonl(addr))) {
    130
    131 /* lease is not taken */
    132 ret = htonl(addr);
    133 lease = find_lease_by_yiaddr(ret);
    134
    135 /* no lease or it expired and we are checking for expired leases */
    136 if ( (!lease || (check_expired && lease_expired(lease)))
    137 && /* and it isn't on the network */ !check_ip(ret)
    138 ) {
    139 return ret;
    140 break;
    141 }
    142 }
    143 }
    144 return 0;
    145 }