On 07.12.2015 18:43, ion.grig...@freescale.com wrote:
> 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))
0x7e5a is in CPU endianness at compile time. You're using odp_be_to_cpu_16()
that leads
to converting that digit to BE endianness. That is why that code works. It
works because
udp->chksum is in BE and resulting digit in right side is also in BE.
But, that is illogical to use function odp_be_to_cpu_16() to convert from CPU
to BE.
On 07.12.2015 19:27, Ion Grigore wrote:
>
> The comparison is done in the CPU endianness.
NO, comparison is done in BE endianness.
Best regards, Ilya Maximets.
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