On Tue, Jul 2, 2024 at 10:56 PM Jun Wang <[email protected]> wrote:
>
> We encountered a scenario where, if the received packet contains
> padding bytes, and we then add Geneve tunnel encapsulation without
> carrying the padding bytes, it results in checksum errors when sending
> out. Therefore, adding an inner_l2_pad is necessary.
>
> For example, this type of packet format:
> 0000 06 6c 6a 71 e1 d3 6c e2 d3 8b ea 24 81 00 03 e9
> 0010 08 00 45 00 00 28 9d e5 40 00 3b 06 6e 64 0a 6f
> 0020 05 14 0a fe 19 06 01 bb 22 ae 59 c0 8c 61 8e 26
> 0030 14 e3 50 10 00 7f ce 3a 00 00 00 00 9e 38 cf 64
Hello Jun,
Thank you for this submission. This is an interesting case and I don't
know that we have an appropriate test case for micrograms like this.
Was this the
One question I have is shouldn't we remove the padding while we
encapsulate, not keep it? The encapsulation should always push the
frame size past 64 bytes.
Thanks,
M
>
> Fixes: 084c8087292c ("userspace: Support VXLAN and GENEVE TSO.")
>
> Signed-off-by: Jun Wang <[email protected]>
> ---
> lib/dp-packet.h | 21 ++++++++++++++++++++-
> lib/netdev-native-tnl.c | 3 +++
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/lib/dp-packet.h b/lib/dp-packet.h
> index a75b1c5..d583b28 100644
> --- a/lib/dp-packet.h
> +++ b/lib/dp-packet.h
> @@ -176,6 +176,8 @@ struct dp_packet {
> ovs_be32 packet_type; /* Packet type as defined in OpenFlow */
> uint16_t csum_start; /* Position to start checksumming from. */
> uint16_t csum_offset; /* Offset to place checksum. */
> + uint16_t inner_l2_pad_size; /* Detected inner l2 padding size.
> + * Padding is non-pullable. */
> union {
> struct pkt_metadata md;
> uint64_t data[DP_PACKET_CONTEXT_SIZE / 8];
> @@ -209,7 +211,10 @@ static inline void *dp_packet_eth(const struct dp_packet
> *);
> static inline void dp_packet_reset_offsets(struct dp_packet *);
> static inline void dp_packet_reset_offload(struct dp_packet *);
> static inline uint16_t dp_packet_l2_pad_size(const struct dp_packet *);
> +static inline uint16_t dp_packet_inner_l2_pad_size(const struct dp_packet *);
> static inline void dp_packet_set_l2_pad_size(struct dp_packet *, uint16_t);
> +static inline void dp_packet_set_inner_l2_pad_size(struct dp_packet *,
> + uint16_t);
> static inline void *dp_packet_l2_5(const struct dp_packet *);
> static inline void dp_packet_set_l2_5(struct dp_packet *, void *);
> static inline void *dp_packet_l3(const struct dp_packet *);
> @@ -435,6 +440,7 @@ static inline void
> dp_packet_reset_offsets(struct dp_packet *b)
> {
> b->l2_pad_size = 0;
> + b->inner_l2_pad_size = 0;
> b->l2_5_ofs = UINT16_MAX;
> b->l3_ofs = UINT16_MAX;
> b->l4_ofs = UINT16_MAX;
> @@ -448,6 +454,12 @@ dp_packet_l2_pad_size(const struct dp_packet *b)
> return b->l2_pad_size;
> }
>
> +static inline uint16_t
> +dp_packet_inner_l2_pad_size(const struct dp_packet *b)
> +{
> + return b->inner_l2_pad_size;
> +}
> +
> static inline void
> dp_packet_set_l2_pad_size(struct dp_packet *b, uint16_t pad_size)
> {
> @@ -455,6 +467,13 @@ dp_packet_set_l2_pad_size(struct dp_packet *b, uint16_t
> pad_size)
> b->l2_pad_size = pad_size;
> }
>
> +static inline void
> +dp_packet_set_inner_l2_pad_size(struct dp_packet *b, uint16_t pad_size)
> +{
> + ovs_assert(pad_size <= dp_packet_size(b));
> + b->inner_l2_pad_size = pad_size;
> +}
> +
> static inline void *
> dp_packet_l2_5(const struct dp_packet *b)
> {
> @@ -543,7 +562,7 @@ dp_packet_inner_l4_size(const struct dp_packet *b)
> return OVS_LIKELY(b->inner_l4_ofs != UINT16_MAX)
> ? (const char *) dp_packet_tail(b)
> - (const char *) dp_packet_inner_l4(b)
> - - dp_packet_l2_pad_size(b)
> + - dp_packet_inner_l2_pad_size(b)
> : 0;
> }
>
> diff --git a/lib/netdev-native-tnl.c b/lib/netdev-native-tnl.c
> index 0f9f07f..96ffdc1 100644
> --- a/lib/netdev-native-tnl.c
> +++ b/lib/netdev-native-tnl.c
> @@ -156,6 +156,7 @@ netdev_tnl_push_ip_header(struct dp_packet *packet, const
> void *header,
> struct eth_header *eth;
> struct ip_header *ip;
> struct ovs_16aligned_ip6_hdr *ip6;
> + uint16_t l2_pad_size;
>
> eth = dp_packet_push_uninit(packet, size);
> *ip_tot_size = dp_packet_size(packet) - sizeof (struct eth_header);
> @@ -163,7 +164,9 @@ netdev_tnl_push_ip_header(struct dp_packet *packet, const
> void *header,
> memcpy(eth, header, size);
> /* The encapsulated packet has type Ethernet. Adjust dp_packet. */
> packet->packet_type = htonl(PT_ETH);
> + l2_pad_size = dp_packet_l2_pad_size(packet);
> dp_packet_reset_offsets(packet);
> + dp_packet_set_inner_l2_pad_size(packet, l2_pad_size);
> packet->l3_ofs = sizeof (struct eth_header);
>
> if (netdev_tnl_is_header_ipv6(header)) {
> --
> 1.8.3.1
>
>
>
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>
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