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

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    Revision 532 - (hide annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 9 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 niro 532 /* 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     }