From: Asias He <asias.hejun@gmail.com>
Date: Sun, 17 Jul 2011 08:56:51 +0000 (+0800)
Subject: kvm tools: Add helper to tell if a UDP package is a DHCP package
X-Git-Tag: next-20110824~3^2~104
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=402e8e3f19d0fe4a82d7755faee1688004997aa7;p=karo-tx-linux.git

kvm tools: Add helper to tell if a UDP package is a DHCP package

This patch checks:

   - sport and dport

   - magic cookie

to detemine whether a UDP package is a DHCP package.

Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
---

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index 5d0437740fe9..b5c55169f59b 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -61,6 +61,7 @@ OBJS	+= net/uip/tcp.o
 OBJS	+= net/uip/udp.o
 OBJS	+= net/uip/buf.o
 OBJS	+= net/uip/csum.o
+OBJS	+= net/uip/dhcp.o
 OBJS	+= kvm-cmd.o
 OBJS	+= mptable.o
 OBJS	+= rbtree.o
diff --git a/tools/kvm/include/kvm/uip.h b/tools/kvm/include/kvm/uip.h
index c414267bbab7..7c84deab8fc8 100644
--- a/tools/kvm/include/kvm/uip.h
+++ b/tools/kvm/include/kvm/uip.h
@@ -30,9 +30,12 @@
 #define UIP_TCP_FLAG_URG	32
 
 #define UIP_DHCP_VENDOR_SPECIFIC_LEN	312
+#define UIP_DHCP_PORT_SERVER		67
+#define UIP_DHCP_PORT_CLIENT		68
 #define UIP_DHCP_MACPAD_LEN		10
 #define UIP_DHCP_HOSTNAME_LEN		64
 #define UIP_DHCP_FILENAME_LEN		128
+#define UIP_DHCP_MAGIC_COOKIE		0x63825363
 #define UIP_DHCP_MAGIC_COOKIE_LEN	4
 #define UIP_DHCP_OPTION_LEN		(UIP_DHCP_VENDOR_SPECIFIC_LEN - UIP_DHCP_MAGIC_COOKIE_LEN)
 /*
@@ -317,4 +320,5 @@ struct uip_buf *uip_buf_get_free(struct uip_info *info);
 struct uip_buf *uip_buf_clone(struct uip_tx_arg *arg);
 
 int uip_udp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk, struct uip_buf *buf, u8 *payload, int payload_len);
+bool uip_udp_is_dhcp(struct uip_udp *udp);
 #endif /* KVM__UIP_H */
diff --git a/tools/kvm/net/uip/dhcp.c b/tools/kvm/net/uip/dhcp.c
new file mode 100644
index 000000000000..af0407fb2fe5
--- /dev/null
+++ b/tools/kvm/net/uip/dhcp.c
@@ -0,0 +1,17 @@
+#include "kvm/uip.h"
+
+bool uip_udp_is_dhcp(struct uip_udp *udp)
+{
+	struct uip_dhcp *dhcp;
+
+	if (ntohs(udp->sport) != UIP_DHCP_PORT_CLIENT ||
+	    ntohs(udp->dport) != UIP_DHCP_PORT_SERVER)
+		return false;
+
+	dhcp = (struct uip_dhcp *)udp;
+
+	if (ntohl(dhcp->magic_cookie) != UIP_DHCP_MAGIC_COOKIE)
+		return false;
+
+	return true;
+}