Minimum message size is now 300 bytes for crappy DHCP servers :/

ChangeLog

@@ -1,3 +1,4 @@
+Minimum message size is now 300 bytes for crappy DHCP servers :/
 Compile ok on OpenBSD (thanks to icezimm and reb in #gentoo-bsd for testing)
 We check gcc supports -Wextra and friends before using them.
 We now restore the starting MTU value when we exit OR we don't receive a

dhcp.c

@@ -38,8 +38,6 @@
 #include "logger.h"
 #include "socket.h"
 
-#define BROADCAST_FLAG 0x8000
-
 static const char *dhcp_message[] = {
 	[DHCP_DISCOVER] 	= "DHCP_DISCOVER",
 	[DHCP_OFFER]		= "DHCP_OFFER",
@@ -248,7 +246,13 @@ size_t send_message (const interface_t *iface, const dhcp_t *dhcp,
 
 	*p++ = DHCP_END;
 
+#ifdef DHCP_MESSAGE_LENTH_MIN
+	while (p - m < DHCP_MESSAGE_LENTH_MIN)
+		*p++ = DHCP_PAD;
+#endif
+
 	message_length = p - m;
+	logger (LOG_DEBUG, "xx %d\n", message_length);
 
 	memset (&packet, 0, sizeof (struct udp_dhcp_packet));
 	make_dhcp_packet (&packet, (unsigned char *) &message, message_length,

dhcp.h

@@ -31,6 +31,7 @@
 #include "dhcpcd.h"
 #include "interface.h"
 
+
 /* Max MTU - defines dhcp option length */
 #define MTU_MAX				1500
 #define MTU_MIN				576
@@ -40,6 +41,7 @@
 #define DHCP_CLIENT_PORT 	68
 
 #define MAGIC_COOKIE		0x63825363
+#define BROADCAST_FLAG 		0x8000
 
 /* DHCP message OP code */
 #define DHCP_BOOTREQUEST	1
@@ -55,7 +57,6 @@
 #define	DHCP_RELEASE		7
 #define DHCP_INFORM			8
 
-
 /* DHCP options */
 enum DHCP_OPTIONS
 {
@@ -152,6 +153,8 @@ typedef struct dhcp_t
 	char *rootpath;
 } dhcp_t;
 
+
+
 /* Sizes for DHCP options */
 #define DHCP_CHADDR_LEN			16
 #define SERVERNAME_LEN			64
@@ -164,6 +167,9 @@ typedef struct dhcp_t
 #define DHCP_OPTION_LEN			(MTU_MAX - DHCP_FIXED_LEN - DHCP_UDP_LEN \
 							 	- DHCP_RESERVE_LEN)
 
+/* Some crappy DHCP servers require the BOOTP minimum length */
+#define DHCP_MESSAGE_LENTH_MIN	300
+
 typedef struct dhcpmessage_t
 {
 	unsigned char op;				/* message type */