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[PATCHv3] Add odp helper function for udp checksum

Message ID 1398762128-17677-1-git-send-email-weilong.chen@linaro.org
State Under Review
Headers show

Commit Message

Weilong Chen April 29, 2014, 9:02 a.m. UTC 
Signed-off-by: Weilong Chen <weilong.chen@linaro.org>
---
 include/helper/odp_udp.h |   56 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
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Patch

diff --git a/include/helper/odp_udp.h b/include/helper/odp_udp.h
index 738470e..c4ce4b8 100644
--- a/include/helper/odp_udp.h
+++ b/include/helper/odp_udp.h
@@ -33,6 +33,62 @@  typedef struct ODP_PACKED {
 	uint16be_t chksum;   /**< UDP header and data checksum (0 if not used)*/
 } odp_udphdr_t;
 
+/**
+ * UDP checksum
+ *
+ * This function uses odp packet to calc checksum
+ *
+ * @param pkt  calculate chksum for pkt
+ * @return  checksum value
+ */
+static inline uint16_t odp_ipv4_udp_chksum(odp_packet_t pkt)
+{
+	unsigned long sum = 0;
+	odp_udphdr_t *udph;
+	odp_ipv4hdr_t *iph;
+	unsigned short *buf;
+	unsigned short udplen;
+	uint16_t chksum;
+
+	if (!odp_packet_l3_offset(pkt))
+		return 0;
+
+	if (!odp_packet_l4_offset(pkt))
+		return 0;
+
+	iph = (odp_ipv4hdr_t *)odp_packet_l3(pkt);
+	udph = (odp_udphdr_t *)odp_packet_l4(pkt);
+	buf = (unsigned short *)udph;
+	udplen = odp_be_to_cpu_16(udph->length);
+
+	/* the source ip */
+	sum += (iph->src_addr >> 16) & 0xFFFF;
+	sum += (iph->src_addr) & 0xFFFF;
+	/* the dest ip */
+	sum += (iph->dst_addr >> 16) & 0xFFFF;
+	sum += (iph->dst_addr) & 0xFFFF;
+	sum += odp_cpu_to_be_16(ODP_IPPROTO_UDP);
+	/* the length */
+	sum += udph->length;
+
+	while (udplen > 1) {
+		sum += *buf++;
+		udplen -= 2;
+	}
+	/* if any bytes left, pad the bytes and add */
+	if (udplen > 0)
+		sum += ((*buf)&odp_cpu_to_be_16(0xFF00));
+
+	/* Fold sum to 16 bits: add carrier to result */
+	while (sum >> 16)
+		sum = (sum & 0xFFFF) + (sum >> 16);
+	sum = ~sum;
+	/* set computation result */
+	chksum = ((unsigned short)sum == 0x0) ? 0xFFFF
+			  : (unsigned short)sum;
+
+	return chksum;
+}
 
 /** @internal Compile time assert */
 ODP_ASSERT(sizeof(odp_udphdr_t) == ODP_UDPHDR_LEN, ODP_UDPHDR_T__SIZE_ERROR);