See inline comments. -----Original Message----- From: Ilya Maximets [mailto:i.maxim...@samsung.com] Sent: Wednesday, December 09, 2015 12:04 PM To: Grigore Ion-B17953 <ion.grig...@freescale.com>; lng-odp@lists.linaro.org Subject: Re: [PATCHv5] helper : Fix UDP checksum computation
Some comments below. On 09.12.2015 11:59, 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 > - fixes the UDP checksum associated validation test > > Signed-off-by: Grigore Ion <ion.grig...@freescale.com> > --- > v5: > - Checksum in CPU endianness fix added (Ilya Maximets) > v4: > - Verify checksum in CPU endianness in the associated test (Ilya > Maximets) > v3: > - fix the UDP checksum computation in the associated test (Maxim > Uvarov) > 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; This line is also strange. You're using odp_be_to_cpu_16 for 8-bit digit. At this point, iph->proto firstly will be extended to u16 in CPU endianness and after that odp_be_to_cpu_16() will return it to BE. You will have right position of all bytes (8 zero bits + 8 bits of iph->proto), but the way how this done is wrong. [IGR] Here the proto field is added as the LSB in a 16-bit BE value. Do you think the following code clearer ? uint16 val; ... val = iph->proto; sum += odp_be_to_cpu_16(val); > + 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); Same at this point. You're using odp_be_to_cpu_16() to perform opposite operation. May be, better to use byte arrays here to avoid that strange endianness and compiler aware operations. [IGR] Here the last byte is added as the MSB in a 16-bit BE value. Do you think the following code clearer ? if (udplen) { val = *((uint8_t *)buf) << 8; sum += odp_be_to_cpu_16(val); } > + /* 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..152018a 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 (odp_be_to_cpu_16(udp->chksum) != 0x7e5a) > status = -1; > > odp_packet_free(test_packet); > _______________________________________________ lng-odp mailing list lng-odp@lists.linaro.org https://lists.linaro.org/mailman/listinfo/lng-odp