Changeset 2725 in MondoRescue for branches/2.2.9/mindi-busybox/networking/udhcp/leases.c

Timestamp:

Feb 25, 2011, 9:26:54 PM (13 years ago)

Author:

Bruno Cornec

Message:

• Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3

File:

• branches/2.2.9/mindi-busybox/networking/udhcp/leases.c (modified) (2 diffs)

branches/2.2.9/mindi-busybox/networking/udhcp/leases.c

@@ -1 +1 @@
 /* vi: set sw=4 ts=4: */
 /*
- * leases.c -- tools to manage DHCP leases
  * Russ Dill <Russ.Dill@asu.edu> July 2001
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
-
 #include "common.h"
 #include "dhcpd.h"
 
-
 /* Find the oldest expired lease, NULL if there are no expired leases */
-static struct dhcpOfferedAddr *oldest_expired_lease(void)
+static struct dyn_lease *oldest_expired_lease(void)
 {
-    struct dhcpOfferedAddr *oldest = NULL;
-// TODO: use monotonic_sec()
-    unsigned long oldest_lease = time(0);
+    struct dyn_lease *oldest_lease = NULL;
+    leasetime_t oldest_time = time(NULL);
     unsigned i;
 
-    for (i = 0; i < server_config.max_leases; i++)
-        if (oldest_lease > leases[i].expires) {
-            oldest_lease = leases[i].expires;
-            oldest = &(leases[i]);
+    /* Unexpired leases have g_leases[i].expires >= current time
+     * and therefore can't ever match */
+    for (i = 0; i < server_config.max_leases; i++) {
+        if (g_leases[i].expires < oldest_time) {
+            oldest_time = g_leases[i].expires;
+            oldest_lease = &g_leases[i];
         }
-    return oldest;
+    }
+    return oldest_lease;
 }
 
+/* Clear out all leases with matching nonzero chaddr OR yiaddr.
+ * If chaddr == NULL, this is a conflict lease.
+ */
+static void clear_leases(const uint8_t *chaddr, uint32_t yiaddr)
+{
+    unsigned i;
 
-/* clear every lease out that chaddr OR yiaddr matches and is nonzero */
-static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)
-{
-    unsigned i, j;
-
-    for (j = 0; j < 16 && !chaddr[j]; j++)
-        continue;
-
-    for (i = 0; i < server_config.max_leases; i++)
-        if ((j != 16 && memcmp(leases[i].chaddr, chaddr, 16) == 0)
-         || (yiaddr && leases[i].yiaddr == yiaddr)
+    for (i = 0; i < server_config.max_leases; i++) {
+        if ((chaddr && memcmp(g_leases[i].lease_mac, chaddr, 6) == 0)
+         || (yiaddr && g_leases[i].lease_nip == yiaddr)
         ) {
-            memset(&(leases[i]), 0, sizeof(leases[i]));
+            memset(&g_leases[i], 0, sizeof(g_leases[i]));
         }
+    }
 }
 
-
-/* add a lease into the table, clearing out any old ones */
-struct dhcpOfferedAddr *add_lease(const uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)
+/* Add a lease into the table, clearing out any old ones.
+ * If chaddr == NULL, this is a conflict lease.
+ */
+struct dyn_lease* FAST_FUNC add_lease(
+        const uint8_t *chaddr, uint32_t yiaddr,
+        leasetime_t leasetime,
+        const char *hostname, int hostname_len)
 {
-    struct dhcpOfferedAddr *oldest;
+    struct dyn_lease *oldest;
 
     /* clean out any old ones */
-    clear_lease(chaddr, yiaddr);
+    clear_leases(chaddr, yiaddr);
 
     oldest = oldest_expired_lease();
 
     if (oldest) {
-        memcpy(oldest->chaddr, chaddr, 16);
-        oldest->yiaddr = yiaddr;
-        oldest->expires = time(0) + lease;
+        memset(oldest, 0, sizeof(*oldest));
+        if (hostname) {
+            char *p;
+
+            hostname_len++; /* include NUL */
+            if (hostname_len > sizeof(oldest->hostname))
+                hostname_len = sizeof(oldest->hostname);
+            p = safe_strncpy(oldest->hostname, hostname, hostname_len);
+            /* sanitization (s/non-ASCII/^/g) */
+            while (*p) {
+                if (*p < ' ' || *p > 126)
+                    *p = '^';
+                p++;
+            }
+        }
+        if (chaddr)
+            memcpy(oldest->lease_mac, chaddr, 6);
+        oldest->lease_nip = yiaddr;
+        oldest->expires = time(NULL) + leasetime;
     }
 
@@ -62 +82 @@
 }
 
-
-/* true if a lease has expired */
-int lease_expired(struct dhcpOfferedAddr *lease)
+/* True if a lease has expired */
+int FAST_FUNC is_expired_lease(struct dyn_lease *lease)
 {
-    return (lease->expires < (unsigned long) time(0));
+    return (lease->expires < (leasetime_t) time(NULL));
 }
 
-
-/* Find the first lease that matches chaddr, NULL if no match */
-struct dhcpOfferedAddr *find_lease_by_chaddr(const uint8_t *chaddr)
+/* Find the first lease that matches MAC, NULL if no match */
+struct dyn_lease* FAST_FUNC find_lease_by_mac(const uint8_t *mac)
 {
     unsigned i;
 
     for (i = 0; i < server_config.max_leases; i++)
-        if (!memcmp(leases[i].chaddr, chaddr, 16))
-            return &(leases[i]);
+        if (memcmp(g_leases[i].lease_mac, mac, 6) == 0)
+            return &g_leases[i];
 
     return NULL;
 }
 
-
-/* Find the first lease that matches yiaddr, NULL is no match */
-struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr)
+/* Find the first lease that matches IP, NULL is no match */
+struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
 {
     unsigned i;
 
     for (i = 0; i < server_config.max_leases; i++)
-        if (leases[i].yiaddr == yiaddr)
-            return &(leases[i]);
+        if (g_leases[i].lease_nip == nip)
+            return &g_leases[i];
 
     return NULL;
 }
 
-
-/* check is an IP is taken, if it is, add it to the lease table */
-static int nobody_responds_to_arp(uint32_t addr)
+/* Check if the IP is taken; if it is, add it to the lease table */
+static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
 {
-    static const uint8_t blank_chaddr[16]; /* 16 zero bytes */
-
     struct in_addr temp;
     int r;
 
-    r = arpping(addr, server_config.server, server_config.arp, server_config.interface);
+    r = arpping(nip, safe_mac,
+            server_config.server_nip,
+            server_config.server_mac,
+            server_config.interface);
     if (r)
         return r;
 
-    temp.s_addr = addr;
+    temp.s_addr = nip;
     bb_info_msg("%s belongs to someone, reserving it for %u seconds",
         inet_ntoa(temp), (unsigned)server_config.conflict_time);
-    add_lease(blank_chaddr, addr, server_config.conflict_time);
+    add_lease(NULL, nip, server_config.conflict_time, NULL, 0);
     return 0;
 }
 
-
-/* find an assignable address, if check_expired is true, we check all the expired leases as well.
- * Maybe this should try expired leases by age... */
-uint32_t find_address(int check_expired)
+/* Find a new usable (we think) address */
+uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
 {
-    uint32_t addr, ret;
-    struct dhcpOfferedAddr *lease = NULL;
+    uint32_t addr;
+    struct dyn_lease *oldest_lease = NULL;
 
     addr = server_config.start_ip; /* addr is in host order here */
     for (; addr <= server_config.end_ip; addr++) {
+        uint32_t nip;
+        struct dyn_lease *lease;
+
         /* ie, 192.168.55.0 */
-        if (!(addr & 0xFF))
+        if ((addr & 0xff) == 0)
             continue;
         /* ie, 192.168.55.255 */
-        if ((addr & 0xFF) == 0xFF)
+        if ((addr & 0xff) == 0xff)
             continue;
-        /* Only do if it isn't assigned as a static lease */
-        ret = htonl(addr);
-        if (!reservedIp(server_config.static_leases, ret)) {
-            /* lease is not taken */
-            lease = find_lease_by_yiaddr(ret);
-            /* no lease or it expired and we are checking for expired leases */
-            if ((!lease || (check_expired && lease_expired(lease)))
-             && nobody_responds_to_arp(ret) /* it isn't used on the network */
-            ) {
-                return ret;
-            }
+        nip = htonl(addr);
+        /* is this a static lease addr? */
+        if (is_nip_reserved(server_config.static_leases, nip))
+            continue;
+
+        lease = find_lease_by_nip(nip);
+        if (!lease) {
+//TODO: DHCP servers do not always sit on the same subnet as clients: should *ping*, not arp-ping!
+            if (nobody_responds_to_arp(nip, safe_mac))
+                return nip;
+        } else {
+            if (!oldest_lease || lease->expires < oldest_lease->expires)
+                oldest_lease = lease;
         }
     }
+
+    if (oldest_lease
+     && is_expired_lease(oldest_lease)
+     && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac)
+    ) {
+        return oldest_lease->lease_nip;
+    }
+
     return 0;
 }