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

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    Revision 987 - (hide annotations) (download)
    Sun May 30 11:40:40 2010 UTC (14 years ago) by niro
    File MIME type: text/plain
    File size: 4394 byte(s) 
    -added upstream dhcpd patch
    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 niro 987
    68     hostname_len++; /* include NUL */
    69 niro 984 if (hostname_len > sizeof(oldest->hostname))
    70     hostname_len = sizeof(oldest->hostname);
    71     p = safe_strncpy(oldest->hostname, hostname, hostname_len);
    72     /* sanitization (s/non-ASCII/^/g) */
    73     while (*p) {
    74     if (*p < ' ' || *p > 126)
    75     *p = '^';
    76     p++;
    77     }
    78     }
    79     memcpy(oldest->lease_mac, chaddr, 6);
    80     oldest->lease_nip = yiaddr;
    81     oldest->expires = time(NULL) + leasetime;
    82 niro 532 }
    83    
    84     return oldest;
    85     }
    86    
    87    
    88 niro 984 /* True if a lease has expired */
    89     int FAST_FUNC is_expired_lease(struct dyn_lease *lease)
    90 niro 532 {
    91 niro 984 return (lease->expires < (leasetime_t) time(NULL));
    92 niro 532 }
    93    
    94    
    95 niro 984 /* Find the first lease that matches MAC, NULL if no match */
    96     struct dyn_lease* FAST_FUNC find_lease_by_mac(const uint8_t *mac)
    97 niro 532 {
    98 niro 816 unsigned i;
    99 niro 532
    100     for (i = 0; i < server_config.max_leases; i++)
    101 niro 984 if (memcmp(g_leases[i].lease_mac, mac, 6) == 0)
    102     return &g_leases[i];
    103 niro 532
    104     return NULL;
    105     }
    106    
    107    
    108 niro 984 /* Find the first lease that matches IP, NULL is no match */
    109     struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
    110 niro 532 {
    111 niro 816 unsigned i;
    112 niro 532
    113     for (i = 0; i < server_config.max_leases; i++)
    114 niro 984 if (g_leases[i].lease_nip == nip)
    115     return &g_leases[i];
    116 niro 532
    117     return NULL;
    118     }
    119    
    120    
    121 niro 984 /* Check if the IP is taken; if it is, add it to the lease table */
    122     static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
    123 niro 532 {
    124 niro 816 /* 16 zero bytes */
    125     static const uint8_t blank_chaddr[16] = { 0 };
    126     /* = { 0 } helps gcc to put it in rodata, not bss */
    127    
    128 niro 532 struct in_addr temp;
    129 niro 816 int r;
    130 niro 532
    131 niro 984 r = arpping(nip, safe_mac,
    132     server_config.server_nip,
    133     server_config.server_mac,
    134     server_config.interface);
    135 niro 816 if (r)
    136     return r;
    137    
    138 niro 984 temp.s_addr = nip;
    139 niro 816 bb_info_msg("%s belongs to someone, reserving it for %u seconds",
    140     inet_ntoa(temp), (unsigned)server_config.conflict_time);
    141 niro 984 add_lease(blank_chaddr, nip, server_config.conflict_time, NULL, 0);
    142 niro 816 return 0;
    143 niro 532 }
    144    
    145    
    146 niro 984 /* Find a new usable (we think) address */
    147     uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
    148 niro 532 {
    149 niro 984 uint32_t addr;
    150     struct dyn_lease *oldest_lease = NULL;
    151 niro 532
    152 niro 816 addr = server_config.start_ip; /* addr is in host order here */
    153     for (; addr <= server_config.end_ip; addr++) {
    154 niro 984 uint32_t nip;
    155     struct dyn_lease *lease;
    156    
    157 niro 532 /* ie, 192.168.55.0 */
    158 niro 984 if ((addr & 0xff) == 0)
    159 niro 816 continue;
    160 niro 532 /* ie, 192.168.55.255 */
    161 niro 984 if ((addr & 0xff) == 0xff)
    162 niro 816 continue;
    163 niro 984 nip = htonl(addr);
    164     /* is this a static lease addr? */
    165     if (is_nip_reserved(server_config.static_leases, nip))
    166     continue;
    167    
    168     lease = find_lease_by_nip(nip);
    169     if (!lease) {
    170     if (nobody_responds_to_arp(nip, safe_mac))
    171     return nip;
    172     } else {
    173     if (!oldest_lease || lease->expires < oldest_lease->expires)
    174     oldest_lease = lease;
    175 niro 532 }
    176     }
    177 niro 984
    178     if (oldest_lease && is_expired_lease(oldest_lease)
    179     && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac)
    180     ) {
    181     return oldest_lease->lease_nip;
    182     }
    183    
    184 niro 532 return 0;
    185     }