From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: David Ahern <dsahern@kernel.org>, netdev@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org,
prashantbhole.linux@gmail.com, jasowang@redhat.com,
brouer@redhat.com, toshiaki.makita1@gmail.com,
daniel@iogearbox.net, john.fastabend@gmail.com, ast@kernel.org,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
dsahern@gmail.com, David Ahern <dahern@digitalocean.com>
Subject: Re: [PATCH v2 bpf-next 06/17] net: Add IFLA_XDP_EGRESS for XDP programs in the egress path
Date: Fri, 24 Apr 2020 10:57:42 +0200 [thread overview]
Message-ID: <877dy55khl.fsf@toke.dk> (raw)
In-Reply-To: <20200424021148.83015-7-dsahern@kernel.org>
David Ahern <dsahern@kernel.org> writes:
> From: David Ahern <dahern@digitalocean.com>
>
> Running programs in the egress path, on skbs or xdp_frames, does not
> require driver specific resources like Rx path. Accordingly, the
> programs can be run in core code, so add xdp_egress_prog to net_device
> to hold a reference to an attached program.
>
> For UAPI, add IFLA_XDP_EGRESS to if_link.h to specify egress programs,
> add a new attach flag, XDP_ATTACHED_EGRESS_CORE, to denote the
> attach point is at the core level (as opposed to driver or hardware)
> and add IFLA_XDP_EGRESS_CORE_PROG_ID for reporting the program id.
>
> Add egress argument to do_setlink_xdp to denote processing of
> IFLA_XDP_EGRESS versus IFLA_XDP, and add a check that none of the
> existing modes (SKB, DRV or HW) are set since those modes are not
> valid. The expectation is that XDP_FLAGS_HW_MODE will be used later
> (e.g., offloading guest programs).
>
> Add rtnl_xdp_egress_fill and helpers as the egress counterpart to the
> existing rtnl_xdp_fill.
>
> Signed-off-by: David Ahern <dahern@digitalocean.com>
> ---
> include/linux/netdevice.h | 1 +
> include/uapi/linux/if_link.h | 3 +
> net/core/rtnetlink.c | 102 +++++++++++++++++++++++++++--
> tools/include/uapi/linux/if_link.h | 3 +
> 4 files changed, 105 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index a416c838b0ec..e157aed04e91 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -1996,6 +1996,7 @@ struct net_device {
> unsigned int real_num_rx_queues;
>
> struct bpf_prog __rcu *xdp_prog;
> + struct bpf_prog __rcu *xdp_egress_prog;
> unsigned long gro_flush_timeout;
> rx_handler_func_t __rcu *rx_handler;
> void __rcu *rx_handler_data;
> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index 127c704eeba9..b3c6cb2f0f0a 100644
> --- a/include/uapi/linux/if_link.h
> +++ b/include/uapi/linux/if_link.h
> @@ -170,6 +170,7 @@ enum {
> IFLA_PROP_LIST,
> IFLA_ALT_IFNAME, /* Alternative ifname */
> IFLA_PERM_ADDRESS,
> + IFLA_XDP_EGRESS, /* nested attribute with 1 or more IFLA_XDP_ attrs */
> __IFLA_MAX
> };
>
> @@ -988,6 +989,7 @@ enum {
> XDP_ATTACHED_SKB,
> XDP_ATTACHED_HW,
> XDP_ATTACHED_MULTI,
> + XDP_ATTACHED_EGRESS_CORE,
> };
>
> enum {
> @@ -1000,6 +1002,7 @@ enum {
> IFLA_XDP_SKB_PROG_ID,
> IFLA_XDP_HW_PROG_ID,
> IFLA_XDP_EXPECTED_FD,
> + IFLA_XDP_EGRESS_CORE_PROG_ID,
> __IFLA_XDP_MAX,
> };
>
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 4a3e85413688..e6f0eec99058 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -1037,7 +1037,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
> + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_PORT_ID */
> + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_SWITCH_ID */
> + nla_total_size(IFNAMSIZ) /* IFLA_PHYS_PORT_NAME */
> - + rtnl_xdp_size() /* IFLA_XDP */
> + + rtnl_xdp_size() * 2 /* IFLA_XDP and IFLA_XDP_EGRESS */
> + nla_total_size(4) /* IFLA_EVENT */
> + nla_total_size(4) /* IFLA_NEW_NETNSID */
> + nla_total_size(4) /* IFLA_NEW_IFINDEX */
> @@ -1402,6 +1402,42 @@ static int rtnl_fill_link_ifmap(struct sk_buff *skb, struct net_device *dev)
> return 0;
> }
>
> +static u32 rtnl_xdp_egress_prog(struct net_device *dev)
> +{
> + const struct bpf_prog *prog;
> +
> + ASSERT_RTNL();
> +
> + prog = rtnl_dereference(dev->xdp_egress_prog);
> + if (!prog)
> + return 0;
> + return prog->aux->id;
> +}
> +
> +static int rtnl_xdp_egress_report(struct sk_buff *skb, struct net_device *dev,
> + u32 *prog_id, u8 *mode, u8 tgt_mode, u32 attr,
> + u32 (*get_prog_id)(struct net_device *dev))
> +{
> + u32 curr_id;
> + int err;
> +
> + curr_id = get_prog_id(dev);
> + if (!curr_id)
> + return 0;
> +
> + *prog_id = curr_id;
> + err = nla_put_u32(skb, attr, curr_id);
> + if (err)
> + return err;
> +
> + if (*mode != XDP_ATTACHED_NONE)
> + *mode = XDP_ATTACHED_MULTI;
> + else
> + *mode = tgt_mode;
> +
> + return 0;
> +}
> +
> static u32 rtnl_xdp_prog_skb(struct net_device *dev)
> {
> const struct bpf_prog *generic_xdp_prog;
> @@ -1493,6 +1529,42 @@ static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
> return err;
> }
>
> +static int rtnl_xdp_egress_fill(struct sk_buff *skb, struct net_device *dev)
> +{
> + u8 mode = XDP_ATTACHED_NONE;
> + struct nlattr *xdp;
> + u32 prog_id = 0;
> + int err;
> +
> + xdp = nla_nest_start_noflag(skb, IFLA_XDP_EGRESS);
> + if (!xdp)
> + return -EMSGSIZE;
> +
> + err = rtnl_xdp_egress_report(skb, dev, &prog_id, &mode,
> + XDP_ATTACHED_EGRESS_CORE,
> + IFLA_XDP_EGRESS_CORE_PROG_ID,
> + rtnl_xdp_egress_prog);
> + if (err)
> + goto err_cancel;
> +
> + err = nla_put_u8(skb, IFLA_XDP_ATTACHED, mode);
> + if (err)
> + goto err_cancel;
> +
> + if (prog_id && mode != XDP_ATTACHED_MULTI) {
> + err = nla_put_u32(skb, IFLA_XDP_PROG_ID, prog_id);
> + if (err)
> + goto err_cancel;
> + }
> +
> + nla_nest_end(skb, xdp);
> + return 0;
> +
> +err_cancel:
> + nla_nest_cancel(skb, xdp);
> + return err;
> +}
> +
> static u32 rtnl_get_event(unsigned long event)
> {
> u32 rtnl_event_type = IFLA_EVENT_NONE;
> @@ -1750,6 +1822,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
> if (rtnl_xdp_fill(skb, dev))
> goto nla_put_failure;
>
> + if (rtnl_xdp_egress_fill(skb, dev))
> + goto nla_put_failure;
> +
> if (dev->rtnl_link_ops || rtnl_have_link_slave_info(dev)) {
> if (rtnl_link_fill(skb, dev) < 0)
> goto nla_put_failure;
> @@ -1834,6 +1909,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
> [IFLA_ALT_IFNAME] = { .type = NLA_STRING,
> .len = ALTIFNAMSIZ - 1 },
> [IFLA_PERM_ADDRESS] = { .type = NLA_REJECT },
> + [IFLA_XDP_EGRESS] = { .type = NLA_NESTED },
> };
>
> static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
> @@ -2489,7 +2565,8 @@ static int do_set_master(struct net_device *dev, int ifindex,
> #define DO_SETLINK_NOTIFY 0x03
>
> static int do_setlink_xdp(struct net_device *dev, struct nlattr *tb,
> - int *status, struct netlink_ext_ack *extack)
> + int *status, bool egress,
> + struct netlink_ext_ack *extack)
> {
> struct nlattr *xdp[IFLA_XDP_MAX + 1];
> u32 xdp_flags = 0;
> @@ -2505,6 +2582,10 @@ static int do_setlink_xdp(struct net_device *dev, struct nlattr *tb,
>
> if (xdp[IFLA_XDP_FLAGS]) {
> xdp_flags = nla_get_u32(xdp[IFLA_XDP_FLAGS]);
> + if (egress && xdp_flags & XDP_FLAGS_MODES) {
> + NL_SET_ERR_MSG(extack, "XDP_FLAGS_MODES not valid for egress");
> + goto out_einval;
> + }
> if (xdp_flags & ~XDP_FLAGS_MASK)
> goto out_einval;
> if (hweight32(xdp_flags & XDP_FLAGS_MODES) > 1)
> @@ -2522,7 +2603,7 @@ static int do_setlink_xdp(struct net_device *dev, struct nlattr *tb,
>
> err = dev_change_xdp_fd(dev, extack,
> nla_get_s32(xdp[IFLA_XDP_FD]),
> - expected_fd, xdp_flags, false);
> + expected_fd, xdp_flags, egress);
> if (err)
> return err;
>
> @@ -2827,8 +2908,21 @@ static int do_setlink(const struct sk_buff *skb,
> status |= DO_SETLINK_NOTIFY;
> }
>
> + if (tb[IFLA_XDP] && tb[IFLA_XDP_EGRESS]) {
> + NL_SET_ERR_MSG(extack, "IFLA_XDP and IFLA_XDP_EGRESS can not be configured at the same time");
> + err = -EINVAL;
> + goto errout;
> + }
> +
> if (tb[IFLA_XDP]) {
> - err = do_setlink_xdp(dev, tb[IFLA_XDP], &status, extack);
> + err = do_setlink_xdp(dev, tb[IFLA_XDP], &status, false, extack);
> + if (err)
> + goto errout;
> + }
> +
> + if (tb[IFLA_XDP_EGRESS]) {
> + err = do_setlink_xdp(dev, tb[IFLA_XDP_EGRESS], &status, true,
> + extack);
While testing this yesterday, I ran into an issue where attaching an
XDP_EGRESS program would return no error, but nothing was happening.
Spent quite a bit of time scratching my head until I realised that my
test machine had failed to boot the patched kernel, and had fallen back
to an earlier version; i.e., didn't have any xdp_egress support at all.
I think this will be a problem: Since we don't reject unknown netlink
attributes, userspace can't know if xdp_egress is supported. So maybe
it's better to just re-use IFLA_XDP with a new flag, instead of using a
separate attribute?
-Toke
next prev parent reply other threads:[~2020-04-24 8:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 2:11 [PATCH v2 bpf-next 00/17] net: Add support for XDP in egress path David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 01/17] net: Refactor convert_to_xdp_frame David Ahern
2020-04-24 7:27 ` Jesper Dangaard Brouer
2020-04-24 2:11 ` [PATCH v2 bpf-next 02/17] net: Move handling of IFLA_XDP attribute out of do_setlink David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 03/17] net: Add XDP setup and query commands for Tx programs David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 04/17] net: Add BPF_XDP_EGRESS as a bpf_attach_type David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 05/17] xdp: Add xdp_txq_info to xdp_buff David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 06/17] net: Add IFLA_XDP_EGRESS for XDP programs in the egress path David Ahern
2020-04-24 8:57 ` Toke Høiland-Jørgensen [this message]
2020-04-24 20:23 ` David Ahern
2020-04-24 9:56 ` Jesper Dangaard Brouer
2020-04-24 2:11 ` [PATCH v2 bpf-next 07/17] net: Rename do_xdp_generic to do_xdp_generic_rx David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 08/17] net: rename netif_receive_generic_xdp to do_generic_xdp_core David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 09/17] net: set XDP egress program on netdevice David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 10/17] net: Support xdp in the Tx path for packets as an skb David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 11/17] net: Support xdp in the Tx path for xdp_frames David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 12/17] libbpf: Refactor get_xdp_info David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 13/17] libbpf: Add egress XDP support David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 14/17] bpftool: Add support for XDP egress David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 15/17] selftest: Add test for xdp_egress David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 16/17] selftest: Add xdp_egress attach tests David Ahern
2020-04-24 2:11 ` [PATCH v2 bpf-next 17/17] samples/bpf: add XDP egress support to xdp1 David Ahern
2020-04-24 4:25 ` [PATCH v2 bpf-next 00/17] net: Add support for XDP in egress path David Ahern
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=877dy55khl.fsf@toke.dk \
--to=toke@redhat.com \
--cc=andriin@fb.com \
--cc=ast@kernel.org \
--cc=brouer@redhat.com \
--cc=dahern@digitalocean.com \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=dsahern@gmail.com \
--cc=dsahern@kernel.org \
--cc=jasowang@redhat.com \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=prashantbhole.linux@gmail.com \
--cc=songliubraving@fb.com \
--cc=toshiaki.makita1@gmail.com \
--cc=yhs@fb.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.