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Message-ID: <176d1001-161c-7ce4-7ccb-8b49375c28a8@iogearbox.net>
Date: Wed, 23 Jan 2019 14:19:49 +0100
From: Daniel Borkmann <daniel@...earbox.net>
To: bjorn.topel@...il.com, ast@...nel.org, netdev@...r.kernel.org
Cc: Björn Töpel <bjorn.topel@...el.com>,
magnus.karlsson@...el.com, magnus.karlsson@...il.com
Subject: Re: [PATCH bpf-next 3/3] xsk: add sock_diag interface for AF_XDP
On 01/18/2019 02:03 PM, bjorn.topel@...il.com wrote:
> From: Björn Töpel <bjorn.topel@...el.com>
>
> This patch adds the sock_diag interface for querying sockets from user
> space. Tools like iproute2 ss(8) can use this interface to list open
> AF_XDP sockets.
>
> The user-space ABI is defined in linux/xdp_diag.h and includes netlink
> request and response structs. The request can query sockets and the
> response contains socket information about the rings, umems, inode and
> more.
>
> Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
Series looks good, few minor nits inline:
> ---
> include/uapi/linux/xdp_diag.h | 72 +++++++++++++
> net/xdp/Kconfig | 8 ++
> net/xdp/Makefile | 1 +
> net/xdp/xsk.c | 6 +-
> net/xdp/xsk.h | 12 +++
> net/xdp/xsk_diag.c | 192 ++++++++++++++++++++++++++++++++++
> 6 files changed, 286 insertions(+), 5 deletions(-)
> create mode 100644 include/uapi/linux/xdp_diag.h
> create mode 100644 net/xdp/xsk.h
> create mode 100644 net/xdp/xsk_diag.c
>
> diff --git a/include/uapi/linux/xdp_diag.h b/include/uapi/linux/xdp_diag.h
> new file mode 100644
> index 000000000000..efe8ce281dce
> --- /dev/null
> +++ b/include/uapi/linux/xdp_diag.h
> @@ -0,0 +1,72 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * xdp_diag: interface for query/monitor XDP sockets
> + * Copyright(c) 2019 Intel Corporation.
> + */
> +
> +#ifndef _LINUX_XDP_DIAG_H
> +#define _LINUX_XDP_DIAG_H
> +
> +#include <linux/types.h>
> +
> +struct xdp_diag_req {
> + __u8 sdiag_family;
> + __u8 sdiag_protocol;
> + __u16 pad;
Presumably this one is for future use? Maybe better as '__u16 :16;' to
avoid compile errors if someone tries to zero 'pad' member manually?
> + __u32 xdiag_ino;
> + __u32 xdiag_show;
> + __u32 xdiag_cookie[2];
> +};
> +
> +struct xdp_diag_msg {
> + __u8 xdiag_family;
> + __u8 xdiag_type;
> + __u32 xdiag_ino;
> + __u32 xdiag_cookie[2];
> +};
> +
> +#define XDP_SHOW_INFO (1 << 0) /* Basic information */
> +#define XDP_SHOW_RING_CFG (1 << 1)
> +#define XDP_SHOW_UMEM (1 << 2)
> +#define XDP_SHOW_MEMINFO (1 << 3)
> +
> +enum {
> + XDP_DIAG_NONE,
> + XDP_DIAG_INFO,
> + XDP_DIAG_UID,
> + XDP_DIAG_RX_RING,
> + XDP_DIAG_TX_RING,
> + XDP_DIAG_UMEM,
> + XDP_DIAG_UMEM_FILL_RING,
> + XDP_DIAG_UMEM_COMPLETION_RING,
> + XDP_DIAG_MEMINFO,
> + __XDP_DIAG_MAX,
> +};
> +
> +#define XDP_DIAG_MAX (__XDP_DIAG_MAX - 1)
> +
> +struct xdp_diag_info {
> + __u32 ifindex;
> + __u32 queue_id;
> +};
> +
> +struct xdp_diag_ring {
> + __u32 entries; /*num descs */
> +};
> +
> +#define XDP_DU_F_ZEROCOPY (1 << 0)
> +
> +struct xdp_diag_umem {
> + __u64 size;
> + __u32 id;
> + __u32 num_pages;
> + __u32 chunk_size;
> + __u32 headroom;
> + __u32 ifindex;
> + __u32 queue_id;
> + __u32 flags;
> + __u32 refs;
> +};
> +
> +
Nit: one newline too much
> +#endif /* _LINUX_XDP_DIAG_H */
> diff --git a/net/xdp/Kconfig b/net/xdp/Kconfig
> index 90e4a7152854..0255b33cff4b 100644
> --- a/net/xdp/Kconfig
> +++ b/net/xdp/Kconfig
> @@ -5,3 +5,11 @@ config XDP_SOCKETS
> help
> XDP sockets allows a channel between XDP programs and
> userspace applications.
> +
> +config XDP_SOCKETS_DIAG
> + tristate "XDP sockets: monitoring interface"
> + depends on XDP_SOCKETS
> + default n
> + help
> + Support for PF_XDP sockets monitoring interface used by the ss tool.
> + If unsure, say Y.
> diff --git a/net/xdp/Makefile b/net/xdp/Makefile
> index 04f073146256..59dbfdf93dca 100644
> --- a/net/xdp/Makefile
> +++ b/net/xdp/Makefile
> @@ -1 +1,2 @@
> obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o xsk_queue.o
> +obj-$(CONFIG_XDP_SOCKETS_DIAG) += xsk_diag.o
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index 80ca48cefc42..949d3bbccb2f 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -27,14 +27,10 @@
>
> #include "xsk_queue.h"
> #include "xdp_umem.h"
> +#include "xsk.h"
>
> #define TX_BATCH_SIZE 16
>
> -static struct xdp_sock *xdp_sk(struct sock *sk)
> -{
> - return (struct xdp_sock *)sk;
> -}
> -
> bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs)
> {
> return READ_ONCE(xs->rx) && READ_ONCE(xs->umem) &&
> diff --git a/net/xdp/xsk.h b/net/xdp/xsk.h
> new file mode 100644
> index 000000000000..ba8120610426
> --- /dev/null
> +++ b/net/xdp/xsk.h
> @@ -0,0 +1,12 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright(c) 2019 Intel Corporation. */
> +
> +#ifndef XSK_H_
> +#define XSK_H_
> +
> +static inline struct xdp_sock *xdp_sk(struct sock *sk)
> +{
> + return (struct xdp_sock *)sk;
> +}
> +
> +#endif /* XSK_H_ */
> diff --git a/net/xdp/xsk_diag.c b/net/xdp/xsk_diag.c
> new file mode 100644
> index 000000000000..2585d7a4ac2f
> --- /dev/null
> +++ b/net/xdp/xsk_diag.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* XDP sockets monitoring support
> + *
> + * Copyright(c) 2019 Intel Corporation.
> + *
> + * Author: Björn Töpel <bjorn.topel@...el.com>
> + */
> +
> +#include <linux/module.h>
> +#include <net/xdp_sock.h>
> +#include <linux/xdp_diag.h>
> +#include <linux/sock_diag.h>
> +
> +#include "xsk_queue.h"
> +#include "xsk.h"
> +
> +static int xsk_diag_put_info(const struct xdp_sock *xs, struct sk_buff *nlskb)
> +{
> + struct xdp_diag_info di;
Not a bug, but can we generally zero all the structs on stack such that once
we extend them nothing gets potentially leaked.
> + di.ifindex = xs->dev ? xs->dev->ifindex : 0;
> + di.queue_id = xs->queue_id;
> + return nla_put(nlskb, XDP_DIAG_INFO, sizeof(di), &di);
> +}
> +
> +static int xsk_diag_put_ring(const struct xsk_queue *queue, int nl_type,
> + struct sk_buff *nlskb)
> +{
> + struct xdp_diag_ring dr;
Ditto.
> + dr.entries = queue->nentries;
> + return nla_put(nlskb, nl_type, sizeof(dr), &dr);
> +}
> +
> +static int xsk_diag_put_rings_cfg(const struct xdp_sock *xs,
> + struct sk_buff *nlskb)
> +{
> + int err = 0;
> +
> + if (xs->rx)
> + err = xsk_diag_put_ring(xs->rx, XDP_DIAG_RX_RING, nlskb);
> + if (!err && xs->tx)
> + err = xsk_diag_put_ring(xs->tx, XDP_DIAG_TX_RING, nlskb);
> + return err;
> +}
> +
> +static int xsk_diag_put_umem(const struct xdp_sock *xs, struct sk_buff *nlskb)
> +{
> + struct xdp_umem *umem = xs->umem;
> + struct xdp_diag_umem du;
Ditto
> + int err;
> +
> + if (!umem)
> + return 0;
> +
> + du.id = umem->id;
> + du.size = umem->size;
> + du.num_pages = umem->npgs;
> + du.chunk_size = (__u32)(~umem->chunk_mask + 1);
> + du.headroom = umem->headroom;
> + du.ifindex = umem->dev ? umem->dev->ifindex : 0;
> + du.queue_id = umem->queue_id;
> + du.flags = 0;
> + if (umem->zc)
> + du.flags |= XDP_DU_F_ZEROCOPY;
> + du.refs = refcount_read(&umem->users);
> +
> + err = nla_put(nlskb, XDP_DIAG_UMEM, sizeof(du), &du);
> +
> + if (!err && umem->fq)
> + err = xsk_diag_put_ring(xs->tx, XDP_DIAG_UMEM_FILL_RING, nlskb);
> + if (!err && umem->cq) {
> + err = xsk_diag_put_ring(xs->tx, XDP_DIAG_UMEM_COMPLETION_RING,
> + nlskb);
> + }
> + return err;
> +}
> +
> +static int xsk_diag_fill(struct sock *sk, struct sk_buff *nlskb,
> + struct xdp_diag_req *req,
> + struct user_namespace *user_ns,
> + u32 portid, u32 seq, u32 flags, int sk_ino)
> +{
> + struct xdp_sock *xs = xdp_sk(sk);
> + struct xdp_diag_msg *msg;
> + struct nlmsghdr *nlh;
> +
> + nlh = nlmsg_put(nlskb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*msg),
> + flags);
> + if (!nlh)
> + return -EMSGSIZE;
> +
> + msg = nlmsg_data(nlh);
> + msg->xdiag_family = AF_XDP;
> + msg->xdiag_type = sk->sk_type;
> + msg->xdiag_ino = sk_ino;
> + sock_diag_save_cookie(sk, msg->xdiag_cookie);
Don't we have a hole in struct xdp_diag_msg after xdiag_type? Probably better
to memset everything in the beginning as well.
> + if ((req->xdiag_show & XDP_SHOW_INFO) && xsk_diag_put_info(xs, nlskb))
> + goto out_nlmsg_trim;
> +
> + if ((req->xdiag_show & XDP_SHOW_INFO) &&
> + nla_put_u32(nlskb, XDP_DIAG_UID,
> + from_kuid_munged(user_ns, sock_i_uid(sk))))
> + goto out_nlmsg_trim;
> +
> + if ((req->xdiag_show & XDP_SHOW_RING_CFG) &&
> + xsk_diag_put_rings_cfg(xs, nlskb))
> + goto out_nlmsg_trim;
> +
> + if ((req->xdiag_show & XDP_SHOW_UMEM) &&
> + xsk_diag_put_umem(xs, nlskb))
> + goto out_nlmsg_trim;
> +
> + if ((req->xdiag_show & XDP_SHOW_MEMINFO) &&
> + sock_diag_put_meminfo(sk, nlskb, XDP_DIAG_MEMINFO))
> + goto out_nlmsg_trim;
> +
> + nlmsg_end(nlskb, nlh);
> + return 0;
> +
> +out_nlmsg_trim:
> + nlmsg_cancel(nlskb, nlh);
> + return -EMSGSIZE;
> +}
> +
> +static int xsk_diag_dump(struct sk_buff *nlskb, struct netlink_callback *cb)
> +{
> + struct xdp_diag_req *req = nlmsg_data(cb->nlh);
> + struct net *net = sock_net(nlskb->sk);
> + int num = 0, s_num = cb->args[0];
> + struct sock *sk;
> +
> + mutex_lock(&net->xdp.lock);
> +
> + sk_for_each(sk, &net->xdp.list) {
> + if (!net_eq(sock_net(sk), net))
> + continue;
> + if (num++ < s_num)
> + continue;
> +
> + if (xsk_diag_fill(sk, nlskb, req,
> + sk_user_ns(NETLINK_CB(cb->skb).sk),
> + NETLINK_CB(cb->skb).portid,
> + cb->nlh->nlmsg_seq, NLM_F_MULTI,
> + sock_i_ino(sk)) < 0) {
> + num--;
> + break;
> + }
> + }
> +
> + mutex_unlock(&net->xdp.lock);
> + cb->args[0] = num;
> + return nlskb->len;
> +}
> +
> +static int xsk_diag_handler_dump(struct sk_buff *nlskb, struct nlmsghdr *hdr)
> +{
> + struct netlink_dump_control c = { .dump = xsk_diag_dump };
> + int hdrlen = sizeof(struct xdp_diag_req);
> + struct net *net = sock_net(nlskb->sk);
> + struct xdp_diag_req *req;
> +
> + if (nlmsg_len(hdr) < hdrlen)
> + return -EINVAL;
> +
> + if (!(hdr->nlmsg_flags & NLM_F_DUMP))
> + return -EOPNOTSUPP;
> +
> + req = nlmsg_data(hdr);
> + return netlink_dump_start(net->diag_nlsk, nlskb, hdr, &c);
> +}
> +
> +static const struct sock_diag_handler xsk_diag_handler = {
> + .family = AF_XDP,
> + .dump = xsk_diag_handler_dump,
> +};
> +
> +static int __init xsk_diag_init(void)
> +{
> + return sock_diag_register(&xsk_diag_handler);
> +}
> +
> +static void __exit xsk_diag_exit(void)
> +{
> + sock_diag_unregister(&xsk_diag_handler);
> +}
> +
> +module_init(xsk_diag_init);
> +module_exit(xsk_diag_exit);
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, AF_XDP);
>
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