udhcpd: disable opton to have absolute lease times in lease file

 (that does not work with dumpleases)
dumpleases: fix -a option.
networking/udhcp/*: code shrink, more compact static leases struture,
 better comments, etc

function                                             old     new   delta
find_free_or_expired_address                           -     147    +147
nobody_responds_to_arp                                 -      84     +84
read_opt                                             781     830     +49
dumpleases_main                                      435     447     +12
send_ACK                                             229     232      +3
read_staticlease                                      90      93      +3
addStaticLease                                        60      61      +1
getIpByMac                                            46      43      -3
reservedIp                                            31      20     -11
keywords                                             304     288     -16
send_offer                                           428     403     -25
write_leases                                         225     193     -32
read_leases                                          184     143     -41
read_yn                                               64       -     -64
find_address                                         191       -    -191
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 5/6 up/down: 299/-383)          Total: -84 bytes

1 files changed, 24 insertions, 12 deletions

diff --git a/networking/udhcp/dhcpd.h b/networking/udhcp/dhcpd.h
index 2d9752845..02e392aaf 100644
--- a/networking/udhcp/dhcpd.h
+++ b/networking/udhcp/dhcpd.h
@@ -26,8 +26,8 @@ struct option_set {
 
 struct static_lease {
         struct static_lease *next;
-        uint8_t *mac;
-        uint32_t *ip;
+        uint32_t ip;
+        uint8_t mac[6];
 };
 
 struct server_config_t {
@@ -42,8 +42,11 @@ struct server_config_t {
         char *interface;                /* The name of the interface to use */
         int ifindex;                    /* Index number of the interface to use */
         uint8_t arp[6];                 /* Our arp address */
-        char remaining;                 /* should the lease file be interpreted as lease time remaining, or
-                                         * as the time the lease expires */
+// disabled: dumpleases has no way of knowing this value,
+// and will break if it's off. Now it's on always.
+//      char remaining;                 /* Should the lease time in lease file
+//                                       * be written as lease time remaining, or
+//                                       * as the absolute time the lease expires */
         uint32_t lease;                 /* lease time in seconds (host order) */
         uint32_t max_leases;            /* maximum number of leases (including reserved address) */
         uint32_t auto_time;             /* how long should udhcpd wait before writing a config file.
@@ -52,11 +55,11 @@ struct server_config_t {
                                          * decline message */
         uint32_t conflict_time;         /* how long an arp conflict offender is leased for */
         uint32_t offer_time;            /* how long an offered address is reserved */
-        uint32_t min_lease;             /* minimum lease a client can request */
+        uint32_t min_lease;             /* minimum lease time a client can request */
+        uint32_t siaddr;                /* next server bootp option */
         char *lease_file;
         char *pidfile;
         char *notify_file;              /* What to run whenever leases are written */
-        uint32_t siaddr;                /* next server bootp option */
         char *sname;                    /* bootp server name */
         char *boot_file;                /* bootp boot file option */
         struct static_lease *static_leases; /* List of ip/mac pairs to assign static leases */
@@ -76,28 +79,37 @@ extern struct dhcpOfferedAddr *leases;
 
 /*** leases.h ***/
 
+typedef uint32_t leasetime_t;
+typedef int32_t signed_leasetime_t;
+
 struct dhcpOfferedAddr {
         uint8_t chaddr[16];
-        uint32_t yiaddr;        /* network order */
-        uint32_t expires;       /* host order */
+        /* In network order */
+        uint32_t yiaddr;
+        /* Unix time when lease expires, regardless of value of
+         * server_config.remaining. Kept in memory in host order.
+         * When written to file, converted to network order
+         * and optionally adjusted (current time subtracted)
+         * if server_config.remaining = 1 */
+        leasetime_t expires;
 };
 
-struct dhcpOfferedAddr *add_lease(const uint8_t *chaddr, uint32_t yiaddr, unsigned long lease) FAST_FUNC;
+struct dhcpOfferedAddr *add_lease(const uint8_t *chaddr, uint32_t yiaddr, leasetime_t leasetime) FAST_FUNC;
 int lease_expired(struct dhcpOfferedAddr *lease) FAST_FUNC;
 struct dhcpOfferedAddr *find_lease_by_chaddr(const uint8_t *chaddr) FAST_FUNC;
 struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr) FAST_FUNC;
-uint32_t find_address(int check_expired) FAST_FUNC;
+uint32_t find_free_or_expired_address(void) FAST_FUNC;
 
 
 /*** static_leases.h ***/
 
 /* Config file will pass static lease info to this function which will add it
  * to a data structure that can be searched later */
-int addStaticLease(struct static_lease **lease_struct, uint8_t *mac, uint32_t *ip) FAST_FUNC;
+void addStaticLease(struct static_lease **lease_struct, uint8_t *mac, uint32_t ip) FAST_FUNC;
 /* Check to see if a mac has an associated static lease */
 uint32_t getIpByMac(struct static_lease *lease_struct, void *arg) FAST_FUNC;
 /* Check to see if an ip is reserved as a static ip */
-uint32_t reservedIp(struct static_lease *lease_struct, uint32_t ip) FAST_FUNC;
+int reservedIp(struct static_lease *lease_struct, uint32_t ip) FAST_FUNC;
 /* Print out static leases just to check what's going on (debug code) */
 void printStaticLeases(struct static_lease **lease_struct) FAST_FUNC;