From: Grigore Ion <ion.grig...@freescale.com>

This patch fixes the following problems:
- checksum computation for LE platforms
- checksum is computed in the CPU endianness. The returned result
must be converted to the BE ordering when it is used to update
the UDP checksum in a packet.
- checksum computation for packets having the UDP length not a
multiple of 2
- fix the UDP checksum computation in the associated test

Signed-off-by: Grigore Ion <ion.grig...@freescale.com>
---
 v3:
 - fix the UDP checksum computation in the associated test
 v2:
 - patch updated to the last master (Maxim Uvarov)
 v1:
 - Move variables declaration on top of block. (Maxim Uvarov)
 - Check patch with checkpatch script.  (Maxim Uvarov)
 - L3 header presence is tested twice. (Alexandru Badicioiu)
 - Remove unnecessary check for L3 header presence. (Bill Fischofer)
 - Modify check of odp_packet_l4_offset() return. (Bill Fischofer)
 
 helper/include/odp/helper/udp.h | 55 +++++++++++++++++------------------------
 helper/test/odp_chksum.c        |  4 +--
 2 files changed, 25 insertions(+), 34 deletions(-)

diff --git a/helper/include/odp/helper/udp.h b/helper/include/odp/helper/udp.h
index 06c439b..9e7256d 100644
--- a/helper/include/odp/helper/udp.h
+++ b/helper/include/odp/helper/udp.h
@@ -4,7 +4,6 @@
  * SPDX-License-Identifier:     BSD-3-Clause
  */
 
-
 /**
  * @file
  *
@@ -22,7 +21,6 @@ extern "C" {
 #include <odp/debug.h>
 #include <odp/byteorder.h>
 
-
 /** @addtogroup odph_header ODPH HEADER
  *  @{
  */
@@ -44,46 +42,39 @@ typedef struct ODP_PACKED {
  * This function uses odp packet to calc checksum
  *
  * @param pkt  calculate chksum for pkt
- * @return  checksum value
+ * @return  checksum value in CPU endianness
  */
 static inline uint16_t odph_ipv4_udp_chksum(odp_packet_t pkt)
 {
-       uint32_t sum = 0;
-       odph_udphdr_t *udph;
-       odph_ipv4hdr_t *iph;
-       uint16_t udplen;
-       uint8_t *buf;
-
-       if (!odp_packet_l3_offset(pkt))
-               return 0;
+       odph_ipv4hdr_t  *iph;
+       odph_udphdr_t   *udph;
+       uint32_t        sum;
+       uint16_t        udplen, *buf;
 
-       if (!odp_packet_l4_offset(pkt))
+       if (odp_packet_l4_offset(pkt) == ODP_PACKET_OFFSET_INVALID)
                return 0;
-
        iph = (odph_ipv4hdr_t *)odp_packet_l3_ptr(pkt, NULL);
        udph = (odph_udphdr_t *)odp_packet_l4_ptr(pkt, NULL);
-       udplen = odp_be_to_cpu_16(udph->length);
-
-       /* 32-bit sum of all 16-bit words covered by UDP chksum */
+       /* 32-bit sum of UDP pseudo-header */
        sum = (iph->src_addr & 0xFFFF) + (iph->src_addr >> 16) +
-             (iph->dst_addr & 0xFFFF) + (iph->dst_addr >> 16) +
-             (uint16_t)iph->proto + udplen;
-       for (buf = (uint8_t *)udph; udplen > 1; udplen -= 2) {
-               sum += ((*buf << 8) + *(buf + 1));
-               buf += 2;
-       }
-
-       /* Fold sum to 16 bits: add carrier to result */
-       while (sum >> 16)
-               sum = (sum & 0xFFFF) + (sum >> 16);
-
+                       (iph->dst_addr & 0xFFFF) + (iph->dst_addr >> 16) +
+                       odp_be_to_cpu_16(iph->proto) + udph->length;
+       udplen = odp_be_to_cpu_16(udph->length);
+       buf = (uint16_t *)((void *)udph);
+       /* 32-bit sum of UDP header (checksum field cleared) and UDP data */
+       for ( ; udplen > 1; udplen -= 2)
+               sum += *buf++;
+       /* Length is not a multiple of 2 bytes */
+       if (udplen)
+               sum += odp_be_to_cpu_16(*((uint8_t *)buf) << 8);
+       /* Fold sum to 16 bits */
+       sum = (sum & 0xFFFF) + (sum >> 16);
+       /* Add carrier (0/1) to result */
+       sum += (sum >> 16);
        /* 1's complement */
        sum = ~sum;
-
-       /* set computation result */
-       sum = (sum == 0x0) ? 0xFFFF : sum;
-
-       return sum;
+       /* Set computation result in CPU endianness */
+       return (sum == 0x0) ? 0xFFFF : odp_be_to_cpu_16(sum);
 }
 
 /** @internal Compile time assert */
diff --git a/helper/test/odp_chksum.c b/helper/test/odp_chksum.c
index 1d417a8..2b32111 100644
--- a/helper/test/odp_chksum.c
+++ b/helper/test/odp_chksum.c
@@ -189,14 +189,14 @@ int main(int argc TEST_UNUSED, char *argv[] TEST_UNUSED)
        udp->dst_port = 0;
        udp->length = odp_cpu_to_be_16(udat_size + ODPH_UDPHDR_LEN);
        udp->chksum = 0;
-       udp->chksum = odph_ipv4_udp_chksum(test_packet);
+       udp->chksum = odp_cpu_to_be_16(odph_ipv4_udp_chksum(test_packet));
 
        if (udp->chksum == 0)
                return -1;
 
        printf("chksum = 0x%x\n", udp->chksum);
 
-       if (udp->chksum != 0xab2d)
+       if (udp->chksum != odp_be_to_cpu_16(0x7e5a))
                status = -1;
 
        odp_packet_free(test_packet);
-- 
1.9.3

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