udhcpc: clarify bcast/unicast sends in logs, include server ID

Before:
    sending discover
    sending select for 192.168.1.173
    lease of 192.168.1.173 obtained, lease time 43200
    sending renew to 192.168.1.1
    lease of 192.168.1.173 obtained, lease time 43200
After:
    broadcasting discover
    broadcasting select for 192.168.1.173, server 192.168.1.1
    lease of 192.168.1.173 obtained from 192.168.1.1, lease time 43200
    sending renew to server 192.168.1.1
    lease of 192.168.1.173 obtained from 192.168.1.1, lease time 43200

function                                             old     new   delta
udhcpc_main                                         2580    2610     +30
send_select                                          104     130     +26
send_renew                                            82      99     +17
send_discover                                         94      89      -5
send_decline                                          93      88      -5
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/2 up/down: 73/-10)             Total: 63 bytes
   text	   data	    bss	    dec	    hex	filename
1019732	    559	   5020	1025311	  fa51f	busybox_old
1019898	    559	   5020	1025477	  fa5c5	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

networking/udhcp/dhcpc.c

@@ -729,7 +729,7 @@ static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
 	 */
 	add_client_options(&packet);
 
-	bb_info_msg("sending %s", "discover");
+	bb_simple_info_msg("broadcasting discover");
 	return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
 }
 
@@ -742,6 +742,7 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
 {
 	struct dhcp_packet packet;
 	struct in_addr temp_addr;
+	char server_str[sizeof("255.255.255.255")];
 
 /*
  * RFC 2131 4.3.2 DHCPREQUEST message
@@ -772,8 +773,13 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
 	 */
 	add_client_options(&packet);
 
+	temp_addr.s_addr = server;
+	strcpy(server_str, inet_ntoa(temp_addr));
 	temp_addr.s_addr = requested;
-	bb_info_msg("sending select for %s", inet_ntoa(temp_addr));
+	bb_info_msg("broadcasting select for %s, server %s",
+			inet_ntoa(temp_addr),
+			server_str
+	);
 	return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
 }
 
@@ -782,7 +788,6 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
 static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
 {
 	struct dhcp_packet packet;
-	struct in_addr temp_addr;
 
 /*
  * RFC 2131 4.3.2 DHCPREQUEST message
@@ -813,8 +818,14 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
 	 */
 	add_client_options(&packet);
 
-	temp_addr.s_addr = server;
-	bb_info_msg("sending renew to %s", inet_ntoa(temp_addr));
+	if (server) {
+		struct in_addr temp_addr;
+		temp_addr.s_addr = server;
+		bb_info_msg("sending renew to server %s", inet_ntoa(temp_addr));
+	} else {
+		bb_simple_info_msg("broadcasting renew");
+	}
+
 	return bcast_or_ucast(&packet, ciaddr, server);
 }
 
@@ -843,7 +854,7 @@ static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t req
 
 	udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
 
-	bb_info_msg("sending %s", "decline");
+	bb_simple_info_msg("broadcasting decline");
 	return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
 }
 #endif
@@ -1720,6 +1731,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 				unsigned start;
 				uint32_t lease_seconds;
 				struct in_addr temp_addr;
+				char server_str[sizeof("255.255.255.255")];
 				uint8_t *temp;
 
 				temp = udhcp_get_option32(&packet, DHCP_LEASE_TIME);
@@ -1775,9 +1787,11 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 				}
 #endif
 				/* enter bound state */
+				temp_addr.s_addr = server_addr;
+				strcpy(server_str, inet_ntoa(temp_addr));
 				temp_addr.s_addr = packet.yiaddr;
-				bb_info_msg("lease of %s obtained, lease time %u",
-					inet_ntoa(temp_addr), (unsigned)lease_seconds);
+				bb_info_msg("lease of %s obtained from %s, lease time %u",
+					inet_ntoa(temp_addr), server_str, (unsigned)lease_seconds);
 				requested_ip = packet.yiaddr;
 
 				start = monotonic_sec();