[PATCH v2 19/31] kvm tools: Implement uip_csum_tcp() to calculate TCP checksum

[Asias He <asias.hejun@xxxxxxxxx>]

Signed-off-by: Asias He <asias.hejun@xxxxxxxxx>
---
 tools/kvm/include/kvm/uip.h |    3 +++
 tools/kvm/uip/csum.c        |   30 ++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/tools/kvm/include/kvm/uip.h b/tools/kvm/include/kvm/uip.h
index 46cec20..37c87c6 100644
--- a/tools/kvm/include/kvm/uip.h
+++ b/tools/kvm/include/kvm/uip.h
@@ -28,8 +28,10 @@
 /*
  * IP package maxium len == 64 KBytes
  * IP header == 20 Bytes
+ * TCP header == 20 Bytes
  * UDP header == 8 Bytes
  */
+#define UIP_MAX_TCP_PAYLOAD	(64*1024 - 20 - 20 - 1)
 #define UIP_MAX_UDP_PAYLOAD	(64*1024 - 20 -  8 - 1)
 
 struct uip_eth_addr {
@@ -269,6 +271,7 @@ int uip_tx_do_arp(struct uip_tx_arg *arg);
 
 u16 uip_csum_icmp(struct uip_icmp *icmp);
 u16 uip_csum_udp(struct uip_udp *udp);
+u16 uip_csum_tcp(struct uip_tcp *tcp);
 u16 uip_csum_ip(struct uip_ip *ip);
 
 struct uip_buf *uip_buf_set_used(struct uip_info *info, struct uip_buf *buf);
diff --git a/tools/kvm/uip/csum.c b/tools/kvm/uip/csum.c
index a152a0f..7ca8bad 100644
--- a/tools/kvm/uip/csum.c
+++ b/tools/kvm/uip/csum.c
@@ -60,3 +60,33 @@ u16 uip_csum_udp(struct uip_udp *udp)
 	}
 
 }
+
+u16 uip_csum_tcp(struct uip_tcp *tcp)
+{
+	struct uip_pseudo_hdr hdr;
+	struct uip_ip *ip;
+	u16 tcp_len;
+	u8 *pad;
+
+	ip	  = &tcp->ip;
+	tcp_len   = ntohs(ip->len) - uip_ip_hdrlen(ip);
+
+	hdr.sip   = ip->sip;
+	hdr.dip	  = ip->dip;
+	hdr.zero  = 0;
+	hdr.proto = ip->proto;
+	hdr.len   = htons(tcp_len);
+
+	if (tcp_len > UIP_MAX_TCP_PAYLOAD + 20)
+		pr_warning("tcp_len(%d) is too large", tcp_len);
+
+	if (tcp_len % 2) {
+		pad = (u8 *)&tcp->sport + tcp_len;
+		*pad = 0;
+		memcpy((u8 *)&tcp->sport + tcp_len + 1, &hdr, sizeof(hdr));
+		return uip_csum(0, (u8 *)&tcp->sport, tcp_len + 1 + sizeof(hdr));
+	} else {
+		memcpy((u8 *)&tcp->sport + tcp_len, &hdr, sizeof(hdr));
+		return uip_csum(0, (u8 *)&tcp->sport, tcp_len + sizeof(hdr));
+	}
+}
-- 
1.7.5.4

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