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

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    Revision 984 - (hide annotations) (download)
    Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
    File MIME type: text/plain
    File size: 4356 byte(s) 
    -updated to busybox-1.16.1 and enabled blkid/uuid support in default config
    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 niro 984 *
    6     * Licensed under GPLv2, see file LICENSE in this tarball for details.
    7 niro 532 */
    8    
    9     #include "common.h"
    10     #include "dhcpd.h"
    11    
    12    
    13 niro 816 /* Find the oldest expired lease, NULL if there are no expired leases */
    14 niro 984 static struct dyn_lease *oldest_expired_lease(void)
    15 niro 816 {
    16 niro 984 struct dyn_lease *oldest_lease = NULL;
    17     leasetime_t oldest_time = time(NULL);
    18 niro 816 unsigned i;
    19 niro 532
    20 niro 984 /* Unexpired leases have g_leases[i].expires >= current time
    21     * and therefore can't ever match */
    22     for (i = 0; i < server_config.max_leases; i++) {
    23     if (g_leases[i].expires < oldest_time) {
    24     oldest_time = g_leases[i].expires;
    25     oldest_lease = &g_leases[i];
    26 niro 816 }
    27 niro 984 }
    28     return oldest_lease;
    29 niro 816 }
    30    
    31    
    32 niro 984 /* Clear every lease out that chaddr OR yiaddr matches and is nonzero */
    33 niro 816 static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)
    34 niro 532 {
    35 niro 816 unsigned i, j;
    36 niro 532
    37 niro 816 for (j = 0; j < 16 && !chaddr[j]; j++)
    38     continue;
    39 niro 532
    40 niro 984 for (i = 0; i < server_config.max_leases; i++) {
    41     if ((j != 16 && memcmp(g_leases[i].lease_mac, chaddr, 6) == 0)
    42     || (yiaddr && g_leases[i].lease_nip == yiaddr)
    43 niro 816 ) {
    44 niro 984 memset(&g_leases[i], 0, sizeof(g_leases[i]));
    45 niro 532 }
    46 niro 984 }
    47 niro 532 }
    48    
    49    
    50 niro 984 /* Add a lease into the table, clearing out any old ones */
    51     struct dyn_lease* FAST_FUNC add_lease(
    52     const uint8_t *chaddr, uint32_t yiaddr,
    53     leasetime_t leasetime,
    54     const char *hostname, int hostname_len)
    55 niro 532 {
    56 niro 984 struct dyn_lease *oldest;
    57 niro 532
    58     /* clean out any old ones */
    59     clear_lease(chaddr, yiaddr);
    60    
    61     oldest = oldest_expired_lease();
    62    
    63     if (oldest) {
    64 niro 984 oldest->hostname[0] = '\0';
    65     if (hostname) {
    66     char *p;
    67     if (hostname_len > sizeof(oldest->hostname))
    68     hostname_len = sizeof(oldest->hostname);
    69     p = safe_strncpy(oldest->hostname, hostname, hostname_len);
    70     /* sanitization (s/non-ASCII/^/g) */
    71     while (*p) {
    72     if (*p < ' ' || *p > 126)
    73     *p = '^';
    74     p++;
    75     }
    76     }
    77     memcpy(oldest->lease_mac, chaddr, 6);
    78     oldest->lease_nip = yiaddr;
    79     oldest->expires = time(NULL) + leasetime;
    80 niro 532 }
    81    
    82     return oldest;
    83     }
    84    
    85    
    86 niro 984 /* True if a lease has expired */
    87     int FAST_FUNC is_expired_lease(struct dyn_lease *lease)
    88 niro 532 {
    89 niro 984 return (lease->expires < (leasetime_t) time(NULL));
    90 niro 532 }
    91    
    92    
    93 niro 984 /* Find the first lease that matches MAC, NULL if no match */
    94     struct dyn_lease* FAST_FUNC find_lease_by_mac(const uint8_t *mac)
    95 niro 532 {
    96 niro 816 unsigned i;
    97 niro 532
    98     for (i = 0; i < server_config.max_leases; i++)
    99 niro 984 if (memcmp(g_leases[i].lease_mac, mac, 6) == 0)
    100     return &g_leases[i];
    101 niro 532
    102     return NULL;
    103     }
    104    
    105    
    106 niro 984 /* Find the first lease that matches IP, NULL is no match */
    107     struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
    108 niro 532 {
    109 niro 816 unsigned i;
    110 niro 532
    111     for (i = 0; i < server_config.max_leases; i++)
    112 niro 984 if (g_leases[i].lease_nip == nip)
    113     return &g_leases[i];
    114 niro 532
    115     return NULL;
    116     }
    117    
    118    
    119 niro 984 /* Check if the IP is taken; if it is, add it to the lease table */
    120     static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
    121 niro 532 {
    122 niro 816 /* 16 zero bytes */
    123     static const uint8_t blank_chaddr[16] = { 0 };
    124     /* = { 0 } helps gcc to put it in rodata, not bss */
    125    
    126 niro 532 struct in_addr temp;
    127 niro 816 int r;
    128 niro 532
    129 niro 984 r = arpping(nip, safe_mac,
    130     server_config.server_nip,
    131     server_config.server_mac,
    132     server_config.interface);
    133 niro 816 if (r)
    134     return r;
    135    
    136 niro 984 temp.s_addr = nip;
    137 niro 816 bb_info_msg("%s belongs to someone, reserving it for %u seconds",
    138     inet_ntoa(temp), (unsigned)server_config.conflict_time);
    139 niro 984 add_lease(blank_chaddr, nip, server_config.conflict_time, NULL, 0);
    140 niro 816 return 0;
    141 niro 532 }
    142    
    143    
    144 niro 984 /* Find a new usable (we think) address */
    145     uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
    146 niro 532 {
    147 niro 984 uint32_t addr;
    148     struct dyn_lease *oldest_lease = NULL;
    149 niro 532
    150 niro 816 addr = server_config.start_ip; /* addr is in host order here */
    151     for (; addr <= server_config.end_ip; addr++) {
    152 niro 984 uint32_t nip;
    153     struct dyn_lease *lease;
    154    
    155 niro 532 /* ie, 192.168.55.0 */
    156 niro 984 if ((addr & 0xff) == 0)
    157 niro 816 continue;
    158 niro 532 /* ie, 192.168.55.255 */
    159 niro 984 if ((addr & 0xff) == 0xff)
    160 niro 816 continue;
    161 niro 984 nip = htonl(addr);
    162     /* is this a static lease addr? */
    163     if (is_nip_reserved(server_config.static_leases, nip))
    164     continue;
    165    
    166     lease = find_lease_by_nip(nip);
    167     if (!lease) {
    168     if (nobody_responds_to_arp(nip, safe_mac))
    169     return nip;
    170     } else {
    171     if (!oldest_lease || lease->expires < oldest_lease->expires)
    172     oldest_lease = lease;
    173 niro 532 }
    174     }
    175 niro 984
    176     if (oldest_lease && is_expired_lease(oldest_lease)
    177     && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac)
    178     ) {
    179     return oldest_lease->lease_nip;
    180     }
    181    
    182 niro 532 return 0;
    183     }