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libbpf: add API to get XDP/XSK supported features

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Extend bpf_xdp_query routine in order to get XDP/XSK supported features
of netdev over route netlink interface.
Extend libbpf netlink implementation in order to support netlink_generic
protocol.

Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Co-developed-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/a72609ef4f0de7fee5376c40dbf54ad7f13bfb8d.1675245258.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Lorenzo Bianconi 2023-02-01 11:24:21 +01:00 committed by Alexei Starovoitov
parent 8f1669319c
commit 04d58f1b26
3 changed files with 110 additions and 1 deletions
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3
tools/lib/bpf/libbpf.h
View file

@ -1048,9 +1048,10 @@ struct bpf_xdp_query_opts {
__u32 hw_prog_id; /* output */
__u32 skb_prog_id; /* output */
__u8 attach_mode; /* output */
__u64 feature_flags; /* output */
size_t :0;
};
#define bpf_xdp_query_opts__last_field attach_mode
#define bpf_xdp_query_opts__last_field feature_flags
LIBBPF_API int bpf_xdp_attach(int ifindex, int prog_fd, __u32 flags,
const struct bpf_xdp_attach_opts *opts);

96
tools/lib/bpf/netlink.c
View file

@ -9,6 +9,7 @@
#include <linux/if_ether.h>
#include <linux/pkt_cls.h>
#include <linux/rtnetlink.h>
#include <linux/netdev.h>
#include <sys/socket.h>
#include <errno.h>
#include <time.h>
@ -39,6 +40,12 @@ struct xdp_id_md {
int ifindex;
__u32 flags;
struct xdp_link_info info;
__u64 feature_flags;
};
struct xdp_features_md {
int ifindex;
__u64 flags;
};
static int libbpf_netlink_open(__u32 *nl_pid, int proto)
@ -238,6 +245,43 @@ static int libbpf_netlink_send_recv(struct libbpf_nla_req *req,
return ret;
}
static int parse_genl_family_id(struct nlmsghdr *nh, libbpf_dump_nlmsg_t fn,
void *cookie)
{
struct genlmsghdr *gnl = NLMSG_DATA(nh);
struct nlattr *na = (struct nlattr *)((void *)gnl + GENL_HDRLEN);
struct nlattr *tb[CTRL_ATTR_FAMILY_ID + 1];
__u16 *id = cookie;
libbpf_nla_parse(tb, CTRL_ATTR_FAMILY_ID, na,
NLMSG_PAYLOAD(nh, sizeof(*gnl)), NULL);
if (!tb[CTRL_ATTR_FAMILY_ID])
return NL_CONT;
*id = libbpf_nla_getattr_u16(tb[CTRL_ATTR_FAMILY_ID]);
return NL_DONE;
}
static int libbpf_netlink_resolve_genl_family_id(const char *name,
__u16 len, __u16 *id)
{
struct libbpf_nla_req req = {
.nh.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN),
.nh.nlmsg_type = GENL_ID_CTRL,
.nh.nlmsg_flags = NLM_F_REQUEST,
.gnl.cmd = CTRL_CMD_GETFAMILY,
.gnl.version = 2,
};
int err;
err = nlattr_add(&req, CTRL_ATTR_FAMILY_NAME, name, len);
if (err < 0)
return err;
return libbpf_netlink_send_recv(&req, NETLINK_GENERIC,
parse_genl_family_id, NULL, id);
}
static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd,
__u32 flags)
{
@ -357,6 +401,29 @@ static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb)
return 0;
}
static int parse_xdp_features(struct nlmsghdr *nh, libbpf_dump_nlmsg_t fn,
void *cookie)
{
struct genlmsghdr *gnl = NLMSG_DATA(nh);
struct nlattr *na = (struct nlattr *)((void *)gnl + GENL_HDRLEN);
struct nlattr *tb[NETDEV_CMD_MAX + 1];
struct xdp_features_md *md = cookie;
__u32 ifindex;
libbpf_nla_parse(tb, NETDEV_CMD_MAX, na,
NLMSG_PAYLOAD(nh, sizeof(*gnl)), NULL);
if (!tb[NETDEV_A_DEV_IFINDEX] || !tb[NETDEV_A_DEV_XDP_FEATURES])
return NL_CONT;
ifindex = libbpf_nla_getattr_u32(tb[NETDEV_A_DEV_IFINDEX]);
if (ifindex != md->ifindex)
return NL_CONT;
md->flags = libbpf_nla_getattr_u64(tb[NETDEV_A_DEV_XDP_FEATURES]);
return NL_DONE;
}
int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
{
struct libbpf_nla_req req = {
@ -366,6 +433,10 @@ int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
.ifinfo.ifi_family = AF_PACKET,
};
struct xdp_id_md xdp_id = {};
struct xdp_features_md md = {
.ifindex = ifindex,
};
__u16 id;
int err;
if (!OPTS_VALID(opts, bpf_xdp_query_opts))
@ -393,6 +464,31 @@ int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
OPTS_SET(opts, skb_prog_id, xdp_id.info.skb_prog_id);
OPTS_SET(opts, attach_mode, xdp_id.info.attach_mode);
if (!OPTS_HAS(opts, feature_flags))
return 0;
err = libbpf_netlink_resolve_genl_family_id("netdev", sizeof("netdev"), &id);
if (err < 0)
return libbpf_err(err);
memset(&req, 0, sizeof(req));
req.nh.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
req.nh.nlmsg_flags = NLM_F_REQUEST;
req.nh.nlmsg_type = id;
req.gnl.cmd = NETDEV_CMD_DEV_GET;
req.gnl.version = 2;
err = nlattr_add(&req, NETDEV_A_DEV_IFINDEX, &ifindex, sizeof(ifindex));
if (err < 0)
return err;
err = libbpf_netlink_send_recv(&req, NETLINK_GENERIC,
parse_xdp_features, NULL, &md);
if (err)
return libbpf_err(err);
opts->feature_flags = md.flags;
return 0;
}

12
tools/lib/bpf/nlattr.h
View file

@ -14,6 +14,7 @@
#include <errno.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/genetlink.h>
/* avoid multiple definition of netlink features */
#define __LINUX_NETLINK_H
@ -58,6 +59,7 @@ struct libbpf_nla_req {
union {
struct ifinfomsg ifinfo;
struct tcmsg tc;
struct genlmsghdr gnl;
};
char buf[128];
};
@ -89,11 +91,21 @@ static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla)
return *(uint8_t *)libbpf_nla_data(nla);
}
static inline uint16_t libbpf_nla_getattr_u16(const struct nlattr *nla)
{
return *(uint16_t *)libbpf_nla_data(nla);
}
static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla)
{
return *(uint32_t *)libbpf_nla_data(nla);
}
static inline uint64_t libbpf_nla_getattr_u64(const struct nlattr *nla)
{
return *(uint64_t *)libbpf_nla_data(nla);
}
static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla)
{
return (const char *)libbpf_nla_data(nla);