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, 9 insertions, 6 deletions

diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index 7b4596895..d0a1eba81 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -26,8 +26,7 @@ int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 {
         fd_set rfds;
-        struct timeval tv;
-        int server_socket = -1, bytes, retval, max_sock;
+        int server_socket = -1, retval, max_sock;
         struct dhcpMessage packet;
         uint8_t *state, *server_id, *requested;
         uint32_t server_id_aligned = server_id_aligned; /* for compiler */
@@ -107,6 +106,8 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 
         timeout_end = monotonic_sec() + server_config.auto_time;
         while (1) { /* loop until universe collapses */
+                int bytes;
+                struct timeval tv;
 
                 if (server_socket < 0) {
                         server_socket = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT,
@@ -143,12 +144,15 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                 case SIGTERM:
                         bb_info_msg("Received a SIGTERM");
                         goto ret0;
-                case 0: break;          /* no signal */
-                default: continue;      /* signal or error (probably EINTR) */
+                case 0: /* no signal: read a packet */
+                        break;
+                default: /* signal or error (probably EINTR): back to select */
+                        continue;
                 }
 
-                bytes = udhcp_recv_kernel_packet(&packet, server_socket); /* this waits for a packet - idle */
+                bytes = udhcp_recv_kernel_packet(&packet, server_socket);
                 if (bytes < 0) {
+                        /* bytes can also be -2 ("bad packet data") */
                         if (bytes == -1 && errno != EINTR) {
                                 DEBUG("error on read, %s, reopening socket", strerror(errno));
                                 close(server_socket);
@@ -165,7 +169,6 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 
                 /* Look for a static lease */
                 static_lease_ip = getIpByMac(server_config.static_leases, &packet.chaddr);
-
                 if (static_lease_ip) {
                         bb_info_msg("Found static lease: %x", static_lease_ip);