dhcpd: remember and record hostnames; optimize get_option

dumpleases: show hostnames

function                                             old     new   delta
add_lease                                            230     292     +62
send_offer                                           403     421     +18
send_ACK                                             232     249     +17
read_leases                                          249     258      +9
dumpleases_main                                      604     609      +5
nobody_responds_to_arp                                84      86      +2
udhcp_end_option                                      32      30      -2
udhcp_get_option                                     222     171     -51
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 6/2 up/down: 113/-53)            Total: 60 bytes

1 files changed, 6 insertions, 3 deletions

diff --git a/networking/udhcp/serverpacket.c b/networking/udhcp/serverpacket.c
index afc0fb40d..8b0f1856b 100644
--- a/networking/udhcp/serverpacket.c
+++ b/networking/udhcp/serverpacket.c
@@ -105,7 +105,7 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
         uint32_t req_align;
         uint32_t lease_time_aligned = server_config.lease;
         uint32_t static_lease_ip;
-        uint8_t *req, *lease_time;
+        uint8_t *req, *lease_time, *p_host_name;
         struct option_set *curr;
         struct in_addr addr;
 
@@ -146,7 +146,8 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
                         bb_error_msg("no IP addresses to give - OFFER abandoned");
                         return -1;
                 }
-                if (!add_lease(packet.chaddr, packet.yiaddr, server_config.offer_time)) {
+                p_host_name = get_option(oldpacket, DHCP_HOST_NAME);
+                if (!add_lease(packet.chaddr, packet.yiaddr, server_config.offer_time, p_host_name)) {
                         bb_error_msg("lease pool is full - OFFER abandoned");
                         return -1;
                 }
@@ -201,6 +202,7 @@ int FAST_FUNC send_ACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
         uint8_t *lease_time;
         uint32_t lease_time_aligned = server_config.lease;
         struct in_addr addr;
+        uint8_t *p_host_name;
 
         init_packet(&packet, oldpacket, DHCPACK);
         packet.yiaddr = yiaddr;
@@ -232,7 +234,8 @@ int FAST_FUNC send_ACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
         if (send_packet(&packet, 0) < 0)
                 return -1;
 
-        add_lease(packet.chaddr, packet.yiaddr, lease_time_aligned);
+        p_host_name = get_option(oldpacket, DHCP_HOST_NAME);
+        add_lease(packet.chaddr, packet.yiaddr, lease_time_aligned, p_host_name);
         if (ENABLE_FEATURE_UDHCPD_WRITE_LEASES_EARLY) {
                 /* rewrite the file with leases at every new acceptance */
                 write_leases();