From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
To: Yuan Wang <yuanx.wang@intel.com>,
dev@dpdk.org, Thomas Monjalon <thomas@monjalon.net>,
Ferruh Yigit <ferruh.yigit@amd.com>
Cc: ferruh.yigit@xilinx.com, mdr@ashroe.eu, xiaoyun.li@intel.com,
aman.deep.singh@intel.com, yuying.zhang@intel.com,
qi.z.zhang@intel.com, qiming.yang@intel.com,
jerinjacobk@gmail.com, viacheslavo@nvidia.com,
stephen@networkplumber.org, xuan.ding@intel.com,
hpothula@marvell.com, yaqi.tang@intel.com,
Wenxuan Wu <wenxuanx.wu@intel.com>
Subject: Re: [PATCH v8 2/4] ethdev: introduce protocol hdr based buffer split
Date: Thu, 6 Oct 2022 13:11:52 +0300 [thread overview]
Message-ID: <2e121e35-0f42-beb4-2896-9d1d81b5fff1@oktetlabs.ru> (raw)
In-Reply-To: <20221005231836.215112-3-yuanx.wang@intel.com>
On 10/6/22 02:18, Yuan Wang wrote:
> Currently, Rx buffer split supports length based split. With Rx queue
> offload RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT enabled and Rx packet segment
> configured, PMD will be able to split the received packets into
> multiple segments.
>
> However, length based buffer split is not suitable for NICs that do split
> based on protocol headers. Given an arbitrarily variable length in Rx
> packet segment, it is almost impossible to pass a fixed protocol header to
> driver. Besides, the existence of tunneling results in the composition of
> a packet is various, which makes the situation even worse.
>
> This patch extends current buffer split to support protocol header based
> buffer split. A new proto_hdr field is introduced in the reserved field
> of rte_eth_rxseg_split structure to specify protocol header. The proto_hdr
> field defines the split position of packet, splitting will always happen
> after the protocol header defined in the Rx packet segment. When Rx queue
> offload RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT is enabled and corresponding
> protocol header is configured, driver will split the ingress packets into
> multiple segments.
>
> Examples for proto_hdr field defines:
> To split after ETH-IPV4-UDP, it should be defined as
> proto_hdr = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
> RTE_PTYPE_L4_UDP
>
> For inner ETH-IPV4-UDP, it should be defined as
> proto_hdr = RTE_PTYPE_TUNNEL_GRENAT | RTE_PTYPE_INNER_L2_ETHER |
> RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN | RTE_PTYPE_INNER_L4_UDP
>
> If the protocol header is repeated with the previously defined one,
> the repeated part can be omitted. For example, split after ETH, ETH-IPV4
> and ETH-IPV4-UDP, it should be defined as
> proto_hdr0 = RTE_PTYPE_L2_ETHER
> proto_hdr1 = RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
> proto_hdr2 = RTE_PTYPE_L4_UDP
Ack
>
> struct rte_eth_rxseg_split {
> struct rte_mempool *mp; /* memory pools to allocate segment from */
> uint16_t length; /* segment maximal data length,
> configures split point */
> uint16_t offset; /* data offset from beginning
> of mbuf data buffer */
> /**
> * Proto_hdr defines a bit mask of the protocol sequence as
> * RTE_PTYPE_*, configures split point. The last RTE_PTYPE*
> * in the mask indicates the split position.
> * If one protocol header is defined to split packets into two
> * segments, for non-tunneling packets, the complete protocol
> * sequence should be defined.
> * For tunneling packets, for simplicity,
> * only the tunnel and inner part of comple protocol sequence
> * is required.
> * If several protocol headers are defined to split packets into
> * multi-segments, the repeated parts of adjacent segments
> * should be omitted.
> */
> uint32_t proto_hdr;
> };
Sorry, but I see no reason to repeat in the descrtion.
What is the purpose of the duplication?
>
> If protocol header split can be supported by a PMD, the
> rte_eth_buffer_split_get_supported_hdr_ptypes function can
> be use to obtain a list of these protocol headers.
>
> For example, let's suppose we configured the Rx queue with the
> following segments:
> seg0 - pool0, proto_hdr0=RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4,
> off0=2B
> seg1 - pool1, proto_hdr1=RTE_PTYPE_L4_UDP, off1=128B
> seg2 - pool2, off1=0B
>
> The packet consists of ETH_IPV4_UDP_PAYLOAD will be split like
> following:
> seg0 - ipv4 header @ RTE_PKTMBUF_HEADROOM + 2 in mbuf from pool0
> seg1 - udp header @ 128 in mbuf from pool1
> seg2 - payload @ 0 in mbuf from pool2
>
> Note: NIC will only do split when the packets exactly match all the
> protocol headers in the segments. For example, if ARP packets received
> with above config, the NIC won't do split for ARP packets since
> it does not contains ipv4 header and udp header. These packets will be put
ipv4 -> IPv4, udp -> UDP.
> into the last valid mempool, with zero offset.
What should happen if we have seg1 -> ETH, seg2 -> IPv4, seg3 -
remaining and receive ARP? Will we see ETH header split in seg1
and everything else in the seg3? I would say yes.
May be we should define intended behavior using pseudo-code?
>
> Now buffer split can be configured in two modes. For length based
> buffer split, the mp, length, offset field in Rx packet segment should
> be configured, while the proto_hdr field will be ignored.
> For protocol header based buffer split, the mp, offset, proto_hdr field
> in Rx packet segment should be configured, while the length field will
> be ignored.
>
> The split limitations imposed by underlying driver is reported in the
> rte_eth_dev_info->rx_seg_capa field. The memory attributes for the split
> parts may differ either, dpdk memory and external memory, respectively.
>
> Signed-off-by: Yuan Wang <yuanx.wang@intel.com>
> Signed-off-by: Xuan Ding <xuan.ding@intel.com>
> Signed-off-by: Wenxuan Wu <wenxuanx.wu@intel.com>
> ---
> doc/guides/rel_notes/release_22_11.rst | 4 ++
> lib/ethdev/rte_ethdev.c | 89 ++++++++++++++++++++++----
> lib/ethdev/rte_ethdev.h | 34 +++++++++-
> 3 files changed, 115 insertions(+), 12 deletions(-)
>
> diff --git a/doc/guides/rel_notes/release_22_11.rst b/doc/guides/rel_notes/release_22_11.rst
> index 141fd9442b..4c3a7f8b8b 100644
> --- a/doc/guides/rel_notes/release_22_11.rst
> +++ b/doc/guides/rel_notes/release_22_11.rst
> @@ -127,6 +127,10 @@ New Features
>
> * Added ``rte_eth_buffer_split_get_supported_hdr_ptypes()``, to get supported
> header protocols of a PMD to split.
> + * Ethdev: The ``reserved`` field in the ``rte_eth_rxseg_split`` structure is
> + replaced with ``proto_hdr`` to support protocol header based buffer split.
> + User can choose length or protocol header to configure buffer split
> + according to NIC's capability.
It sounds like it should be mentioned in API change section as
well. Here I'd concentrate on top level feature overview only.
I.e. Supported protocol-based buffer split using added
``proto_hdr`` in structure ``rte_eth_rxseg_split``.
>
>
> Removed Items
> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
> index ee3b490889..60fe6eb2bd 100644
> --- a/lib/ethdev/rte_ethdev.c
> +++ b/lib/ethdev/rte_ethdev.c
> @@ -1650,14 +1650,18 @@ rte_eth_dev_is_removed(uint16_t port_id)
> }
>
> static int
> -rte_eth_rx_queue_check_split(const struct rte_eth_rxseg_split *rx_seg,
> - uint16_t n_seg, uint32_t *mbp_buf_size,
> - const struct rte_eth_dev_info *dev_info)
> +rte_eth_rx_queue_check_split(uint16_t port_id,
> + const struct rte_eth_rxseg_split *rx_seg,
> + uint16_t n_seg, uint32_t *mbp_buf_size,
> + const struct rte_eth_dev_info *dev_info)
> {
> const struct rte_eth_rxseg_capa *seg_capa = &dev_info->rx_seg_capa;
> struct rte_mempool *mp_first;
> uint32_t offset_mask;
> uint16_t seg_idx;
> + int ptype_cnt;
> + uint32_t *ptypes;
> + int i;
>
> if (n_seg > seg_capa->max_nseg) {
> RTE_ETHDEV_LOG(ERR,
> @@ -1675,6 +1679,7 @@ rte_eth_rx_queue_check_split(const struct rte_eth_rxseg_split *rx_seg,
> struct rte_mempool *mpl = rx_seg[seg_idx].mp;
> uint32_t length = rx_seg[seg_idx].length;
> uint32_t offset = rx_seg[seg_idx].offset;
> + uint32_t proto_hdr = rx_seg[seg_idx].proto_hdr;
>
> if (mpl == NULL) {
> RTE_ETHDEV_LOG(ERR, "null mempool pointer\n");
> @@ -1708,13 +1713,75 @@ rte_eth_rx_queue_check_split(const struct rte_eth_rxseg_split *rx_seg,
> }
> offset += seg_idx != 0 ? 0 : RTE_PKTMBUF_HEADROOM;
> *mbp_buf_size = rte_pktmbuf_data_room_size(mpl);
> - length = length != 0 ? length : *mbp_buf_size;
> - if (*mbp_buf_size < length + offset) {
> - RTE_ETHDEV_LOG(ERR,
> - "%s mbuf_data_room_size %u < %u (segment length=%u + segment offset=%u)\n",
> - mpl->name, *mbp_buf_size,
> - length + offset, length, offset);
> - return -EINVAL;
> +
> + if (proto_hdr > 0) {
proto_hdr != 0, please. I know that it is the same, but != 0
raises a bit less question if the field is signed or unsigned.
As the first condition here we should check if protocol-based
split is supported at all (see note about separate helper
function below).
> + /* Split based on protocol headers. */
> + if (length != 0) {
> + RTE_ETHDEV_LOG(ERR,
> + "Do not set length split and protocol split within a segment\n"
> + );
> + return -EINVAL;
> + }
> +
> + if (seg_idx == n_seg - 1) {
> + RTE_ETHDEV_LOG(ERR,
> + "The proto_hdr in the last segment should be 0\n"
> + );
> + return -EINVAL;
> + }
I think here we should check if we have seen any segment
with proto_hdr == 0 before. If so, we can't do protocol
based split any more. Since we need to collect already
split protcols (prev_proto_hdrs), I would use the variable
as a marker and set it to all 1's MASK as soon as
proto_hdr==0 met.
So, the condition will be
if ((proto_hdr & prev_proto_hdrs) != 0)
So, it will check two since no repeat of previou
protocol headers which are already split and no
ptoto-split after length-based split.
> +
> + if (*mbp_buf_size < offset) {
> + RTE_ETHDEV_LOG(ERR,
> + "%s mbuf_data_room_size %u < %u segment offset)\n",
> + mpl->name, *mbp_buf_size,
> + offset);
> + return -EINVAL;
> + }
> +
(separate helper function starts here)
> + ptype_cnt = rte_eth_buffer_split_get_supported_hdr_ptypes(port_id, NULL, 0);
Three is no point to do it in a loop. It should be done
outside. Moreover, it should be a helper function
which does it to make this functionshort.
> + if (ptype_cnt <= 0) {
> + RTE_ETHDEV_LOG(ERR,
> + "Port %u failed to supported buffer split header protocols\n",
> + port_id);
> + return -EINVAL;
> + }
> +
> + ptypes = malloc(sizeof(uint32_t) * ptype_cnt);
> + if (ptypes == NULL)
> + return -ENOMEM;
> +
> + ptype_cnt = rte_eth_buffer_split_get_supported_hdr_ptypes(port_id,
> + ptypes, ptype_cnt);
> + if (ptype_cnt < 0) {
> + RTE_ETHDEV_LOG(ERR,
> + "Port %u failed to supported buffer split header protocols\n",
> + port_id);
> + free(ptypes);
> + return -EINVAL;
> + }
(separate helper function ends here)
> +
> + for (i = 0; i < ptype_cnt; i++)
> + if (ptypes[i] == proto_hdr)
It should be if ((prev_proto_hdrs | proto_hdr) == ptypes[i])
> + break;
> +
> + free(ptypes);
> +
> + if (i == ptype_cnt) {
> + RTE_ETHDEV_LOG(ERR,
> + "Requested Rx split header protocols 0x%x is not supported.\n",
> + proto_hdr);
> + return -EINVAL;
> + }
prev_proto_hdrs |= proto_hdr;
> + } else {
NOTE If driver does not support length-based split,
it should reject such configuration itself.
> + /* Split at fixed length. */
> + length = length != 0 ? length : *mbp_buf_size;
> + if (*mbp_buf_size < length + offset) {
> + RTE_ETHDEV_LOG(ERR,
> + "%s mbuf_data_room_size %u < %u (segment length=%u + segment offset=%u)\n",
> + mpl->name, *mbp_buf_size,
> + length + offset, length, offset);
> + return -EINVAL;
> + }
prev_proto_hdrs = RTE_PTYPE_ALL_MASK;
> }
> }
> return 0;
> @@ -1794,7 +1861,7 @@ rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
> n_seg = rx_conf->rx_nseg;
>
> if (rx_conf->offloads & RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT) {
> - ret = rte_eth_rx_queue_check_split(rx_seg, n_seg,
> + ret = rte_eth_rx_queue_check_split(port_id, rx_seg, n_seg,
> &mbp_buf_size,
> &dev_info);
> if (ret != 0)
> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index c51c1f3fa0..4c9b121355 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -994,6 +994,9 @@ struct rte_eth_txmode {
> * specified in the first array element, the second buffer, from the
> * pool in the second element, and so on.
> *
> + * - The proto_hdrs in the elements define the split position of
> + * received packets.
> + *
> * - The offsets from the segment description elements specify
> * the data offset from the buffer beginning except the first mbuf.
> * The first segment offset is added with RTE_PKTMBUF_HEADROOM.
> @@ -1015,12 +1018,41 @@ struct rte_eth_txmode {
> * - pool from the last valid element
> * - the buffer size from this pool
> * - zero offset
> + *
> + * - Length based buffer split:
> + * - mp, length, offset should be configured.
> + * - The proto_hdr field must be 0.
> + *
> + * - Protocol header based buffer split:
> + * - mp, offset, proto_hdr should be configured.
> + * - The length field must be 0.
> + * - The proto_hdr field in the last segment should be 0.
> + *
> + * - For Protocol header based buffer split, if the received packets
> + * don't exactly match all protocol headers in the elements, packets
> + * will not be split.
> + * These packets will be put into:
> + * - pool from the last valid element
> + * - the buffer size from this pool
> + * - zero offset
> */
> struct rte_eth_rxseg_split {
> struct rte_mempool *mp; /**< Memory pool to allocate segment from. */
> uint16_t length; /**< Segment data length, configures split point. */
> uint16_t offset; /**< Data offset from beginning of mbuf data buffer. */
> - uint32_t reserved; /**< Reserved field. */
> + /**
> + * Proto_hdr defines a bit mask of the protocol sequence as RTE_PTYPE_*,
> + * configures split point. The last RTE_PTYPE* in the mask indicates the
> + * split position.
> + *
> + * If one protocol header is defined to split packets into two segments,
> + * for non-tunneling packets, the complete protocol sequence should be defined.
> + * For tunneling packets, for simplicity, only the tunnel and inner part of
> + * comple protocol sequence is required.
> + * If several protocol headers are defined to split packets into multi-segments,
> + * the repeated parts of adjacent segments should be omitted.
> + */
> + uint32_t proto_hdr;
> };
>
> /**
next prev parent reply other threads:[~2022-10-06 10:11 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 18:15 [PATCH 0/4] support protocol " Yuan Wang
2022-08-12 18:15 ` [PATCH 1/4] ethdev: introduce protocol header API Yuan Wang
2022-08-12 18:15 ` [PATCH 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-08-12 18:15 ` [PATCH 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-08-12 18:15 ` [PATCH 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-09-01 22:33 ` [PATCH v2 0/4] support protocol based buffer split Yuan Wang
2022-09-01 22:34 ` [PATCH v2 1/4] ethdev: introduce protocol header API Yuan Wang
2022-09-01 22:35 ` [PATCH v2 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-09-01 22:36 ` [PATCH v2 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-09-01 22:37 ` [PATCH v2 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-09-02 19:10 ` [PATCH v3 0/4] support protocol based buffer split Yuan Wang
2022-09-02 19:10 ` [PATCH v3 1/4] ethdev: introduce protocol header API Yuan Wang
2022-09-12 11:24 ` Andrew Rybchenko
2022-09-16 8:34 ` Wang, YuanX
2022-09-02 19:10 ` [PATCH v3 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-09-12 11:47 ` Andrew Rybchenko
2022-09-16 8:38 ` Wang, YuanX
2022-09-20 5:35 ` Andrew Rybchenko
2022-09-22 3:13 ` Wang, YuanX
2022-09-13 7:56 ` Suanming Mou
2022-09-16 8:39 ` Wang, YuanX
2022-09-02 19:10 ` [PATCH v3 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-09-02 19:10 ` [PATCH v3 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-09-20 11:12 ` [PATCH v4 0/4] support protocol based buffer split Yuan Wang
2022-09-20 11:12 ` [PATCH v4 1/4] ethdev: introduce protocol header API Yuan Wang
2022-09-20 11:12 ` [PATCH v4 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-09-20 11:12 ` [PATCH v4 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-09-20 11:12 ` [PATCH v4 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-09-26 9:40 ` [PATCH v5 0/4] support protocol based buffer split Yuan Wang
2022-09-26 9:40 ` [PATCH v5 1/4] ethdev: introduce protocol header API Yuan Wang
2022-09-26 9:40 ` [PATCH v5 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-09-28 15:42 ` Wang, YuanX
2022-09-26 9:40 ` [PATCH v5 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-09-26 9:40 ` [PATCH v5 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-09-29 18:59 ` [PATCH v6 0/4] support protocol based buffer split Yuan Wang
2022-09-29 18:59 ` [PATCH v6 1/4] ethdev: introduce protocol header API Yuan Wang
2022-09-29 18:59 ` [PATCH v6 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-09-29 18:59 ` [PATCH v6 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-09-29 18:59 ` [PATCH v6 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-09-30 6:45 ` Tang, Yaqi
2022-10-01 21:05 ` [PATCH v7 0/4] support protocol based buffer split Yuan Wang
2022-10-01 21:05 ` [PATCH v7 1/4] ethdev: introduce protocol header API Yuan Wang
2022-10-03 7:04 ` Andrew Rybchenko
2022-10-04 2:21 ` Wang, YuanX
2022-10-04 7:52 ` Andrew Rybchenko
2022-10-04 15:00 ` Wang, YuanX
2022-10-01 21:05 ` [PATCH v7 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-10-02 4:01 ` Wang, YuanX
2022-10-03 7:47 ` Andrew Rybchenko
2022-10-04 2:48 ` Wang, YuanX
2022-10-04 8:22 ` Andrew Rybchenko
2022-10-04 15:01 ` Wang, YuanX
2022-10-01 21:05 ` [PATCH v7 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-10-01 21:05 ` [PATCH v7 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-10-05 23:18 ` [PATCH v8 0/4] support protocol based buffer split Yuan Wang
2022-10-05 23:18 ` [PATCH v8 1/4] ethdev: introduce protocol header API Yuan Wang
2022-10-06 10:11 ` Andrew Rybchenko
2022-10-05 23:18 ` [PATCH v8 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-10-06 10:11 ` Andrew Rybchenko [this message]
2022-10-08 14:30 ` Ding, Xuan
2022-10-05 23:18 ` [PATCH v8 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-10-06 10:12 ` Andrew Rybchenko
2022-10-05 23:18 ` [PATCH v8 4/4] net/ice: support buffer split in Rx path Yuan Wang
2022-10-06 10:12 ` Andrew Rybchenko
2022-10-06 10:13 ` [PATCH v8 0/4] support protocol based buffer split Andrew Rybchenko
2022-10-09 20:25 ` [PATCH v9 " Yuan Wang
2022-10-09 14:58 ` Andrew Rybchenko
2022-10-10 2:45 ` Ding, Xuan
2022-10-09 20:25 ` [PATCH v9 1/4] ethdev: introduce protocol header API Yuan Wang
2022-10-09 20:25 ` [PATCH v9 2/4] ethdev: introduce protocol hdr based buffer split Yuan Wang
2022-10-09 20:25 ` [PATCH v9 3/4] app/testpmd: add rxhdrs commands and parameters Yuan Wang
2022-10-09 20:25 ` [PATCH v9 4/4] net/ice: support buffer split in Rx path Yuan Wang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2e121e35-0f42-beb4-2896-9d1d81b5fff1@oktetlabs.ru \
--to=andrew.rybchenko@oktetlabs.ru \
--cc=aman.deep.singh@intel.com \
--cc=dev@dpdk.org \
--cc=ferruh.yigit@amd.com \
--cc=ferruh.yigit@xilinx.com \
--cc=hpothula@marvell.com \
--cc=jerinjacobk@gmail.com \
--cc=mdr@ashroe.eu \
--cc=qi.z.zhang@intel.com \
--cc=qiming.yang@intel.com \
--cc=stephen@networkplumber.org \
--cc=thomas@monjalon.net \
--cc=viacheslavo@nvidia.com \
--cc=wenxuanx.wu@intel.com \
--cc=xiaoyun.li@intel.com \
--cc=xuan.ding@intel.com \
--cc=yaqi.tang@intel.com \
--cc=yuanx.wang@intel.com \
--cc=yuying.zhang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).