Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 756 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
new file mode 100644
index 000000000..ff3aa0cf3
--- /dev/null
+++ b/tools/bpf/bpftool/net.c
@@ -0,0 +1,756 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+// Copyright (C) 2018 Facebook
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include <net/if.h>
+#include <linux/rtnetlink.h>
+#include <linux/socket.h>
+#include <linux/tc_act/tc_bpf.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "bpf/nlattr.h"
+#include "main.h"
+#include "netlink_dumper.h"
+
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
+struct ip_devname_ifindex {
+	char	devname[64];
+	int	ifindex;
+};
+
+struct bpf_netdev_t {
+	struct ip_devname_ifindex *devices;
+	int	used_len;
+	int	array_len;
+	int	filter_idx;
+};
+
+struct tc_kind_handle {
+	char	kind[64];
+	int	handle;
+};
+
+struct bpf_tcinfo_t {
+	struct tc_kind_handle	*handle_array;
+	int			used_len;
+	int			array_len;
+	bool			is_qdisc;
+};
+
+struct bpf_filter_t {
+	const char	*kind;
+	const char	*devname;
+	int		ifindex;
+};
+
+struct bpf_attach_info {
+	__u32 flow_dissector_id;
+};
+
+enum net_attach_type {
+	NET_ATTACH_TYPE_XDP,
+	NET_ATTACH_TYPE_XDP_GENERIC,
+	NET_ATTACH_TYPE_XDP_DRIVER,
+	NET_ATTACH_TYPE_XDP_OFFLOAD,
+};
+
+static const char * const attach_type_strings[] = {
+	[NET_ATTACH_TYPE_XDP]		= "xdp",
+	[NET_ATTACH_TYPE_XDP_GENERIC]	= "xdpgeneric",
+	[NET_ATTACH_TYPE_XDP_DRIVER]	= "xdpdrv",
+	[NET_ATTACH_TYPE_XDP_OFFLOAD]	= "xdpoffload",
+};
+
+const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);
+
+static enum net_attach_type parse_attach_type(const char *str)
+{
+	enum net_attach_type type;
+
+	for (type = 0; type < net_attach_type_size; type++) {
+		if (attach_type_strings[type] &&
+		    is_prefix(str, attach_type_strings[type]))
+			return type;
+	}
+
+	return net_attach_type_size;
+}
+
+typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
+
+typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
+
+static int netlink_open(__u32 *nl_pid)
+{
+	struct sockaddr_nl sa;
+	socklen_t addrlen;
+	int one = 1, ret;
+	int sock;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+
+	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (sock < 0)
+		return -errno;
+
+	if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
+		       &one, sizeof(one)) < 0) {
+		p_err("Netlink error reporting not supported");
+	}
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	addrlen = sizeof(sa);
+	if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	if (addrlen != sizeof(sa)) {
+		ret = -LIBBPF_ERRNO__INTERNAL;
+		goto cleanup;
+	}
+
+	*nl_pid = sa.nl_pid;
+	return sock;
+
+cleanup:
+	close(sock);
+	return ret;
+}
+
+static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
+			    __dump_nlmsg_t _fn, dump_nlmsg_t fn,
+			    void *cookie)
+{
+	bool multipart = true;
+	struct nlmsgerr *err;
+	struct nlmsghdr *nh;
+	char buf[4096];
+	int len, ret;
+
+	while (multipart) {
+		multipart = false;
+		len = recv(sock, buf, sizeof(buf), 0);
+		if (len < 0) {
+			ret = -errno;
+			goto done;
+		}
+
+		if (len == 0)
+			break;
+
+		for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
+		     nh = NLMSG_NEXT(nh, len)) {
+			if (nh->nlmsg_pid != nl_pid) {
+				ret = -LIBBPF_ERRNO__WRNGPID;
+				goto done;
+			}
+			if (nh->nlmsg_seq != seq) {
+				ret = -LIBBPF_ERRNO__INVSEQ;
+				goto done;
+			}
+			if (nh->nlmsg_flags & NLM_F_MULTI)
+				multipart = true;
+			switch (nh->nlmsg_type) {
+			case NLMSG_ERROR:
+				err = (struct nlmsgerr *)NLMSG_DATA(nh);
+				if (!err->error)
+					continue;
+				ret = err->error;
+				libbpf_nla_dump_errormsg(nh);
+				goto done;
+			case NLMSG_DONE:
+				return 0;
+			default:
+				break;
+			}
+			if (_fn) {
+				ret = _fn(nh, fn, cookie);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+	ret = 0;
+done:
+	return ret;
+}
+
+static int __dump_class_nlmsg(struct nlmsghdr *nlh,
+			      dump_nlmsg_t dump_class_nlmsg,
+			      void *cookie)
+{
+	struct nlattr *tb[TCA_MAX + 1], *attr;
+	struct tcmsg *t = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
+	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
+	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_class_nlmsg(cookie, t, tb);
+}
+
+static int netlink_get_class(int sock, unsigned int nl_pid, int ifindex,
+			     dump_nlmsg_t dump_class_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct tcmsg t;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
+		.nlh.nlmsg_type = RTM_GETTCLASS,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.t.tcm_family = AF_UNSPEC,
+		.t.tcm_ifindex = ifindex,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
+			    dump_class_nlmsg, cookie);
+}
+
+static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
+			      dump_nlmsg_t dump_qdisc_nlmsg,
+			      void *cookie)
+{
+	struct nlattr *tb[TCA_MAX + 1], *attr;
+	struct tcmsg *t = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
+	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
+	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_qdisc_nlmsg(cookie, t, tb);
+}
+
+static int netlink_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
+			     dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct tcmsg t;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
+		.nlh.nlmsg_type = RTM_GETQDISC,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.t.tcm_family = AF_UNSPEC,
+		.t.tcm_ifindex = ifindex,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
+			    dump_qdisc_nlmsg, cookie);
+}
+
+static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
+			       dump_nlmsg_t dump_filter_nlmsg,
+			       void *cookie)
+{
+	struct nlattr *tb[TCA_MAX + 1], *attr;
+	struct tcmsg *t = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
+	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
+	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_filter_nlmsg(cookie, t, tb);
+}
+
+static int netlink_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
+			      dump_nlmsg_t dump_filter_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct tcmsg t;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
+		.nlh.nlmsg_type = RTM_GETTFILTER,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.t.tcm_family = AF_UNSPEC,
+		.t.tcm_ifindex = ifindex,
+		.t.tcm_parent = handle,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
+			    dump_filter_nlmsg, cookie);
+}
+
+static int __dump_link_nlmsg(struct nlmsghdr *nlh,
+			     dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct nlattr *tb[IFLA_MAX + 1], *attr;
+	struct ifinfomsg *ifi = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
+	attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
+	if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_link_nlmsg(cookie, ifi, tb);
+}
+
+static int netlink_get_link(int sock, unsigned int nl_pid,
+			    dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct ifinfomsg ifm;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+		.nlh.nlmsg_type = RTM_GETLINK,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.ifm.ifi_family = AF_PACKET,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
+			    dump_link_nlmsg, cookie);
+}
+
+static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
+{
+	struct bpf_netdev_t *netinfo = cookie;
+	struct ifinfomsg *ifinfo = msg;
+
+	if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
+		return 0;
+
+	if (netinfo->used_len == netinfo->array_len) {
+		netinfo->devices = realloc(netinfo->devices,
+			(netinfo->array_len + 16) *
+			sizeof(struct ip_devname_ifindex));
+		if (!netinfo->devices)
+			return -ENOMEM;
+
+		netinfo->array_len += 16;
+	}
+	netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
+	snprintf(netinfo->devices[netinfo->used_len].devname,
+		 sizeof(netinfo->devices[netinfo->used_len].devname),
+		 "%s",
+		 tb[IFLA_IFNAME]
+			 ? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
+			 : "");
+	netinfo->used_len++;
+
+	return do_xdp_dump(ifinfo, tb);
+}
+
+static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
+{
+	struct bpf_tcinfo_t *tcinfo = cookie;
+	struct tcmsg *info = msg;
+
+	if (tcinfo->is_qdisc) {
+		/* skip clsact qdisc */
+		if (tb[TCA_KIND] &&
+		    strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
+			return 0;
+		if (info->tcm_handle == 0)
+			return 0;
+	}
+
+	if (tcinfo->used_len == tcinfo->array_len) {
+		tcinfo->handle_array = realloc(tcinfo->handle_array,
+			(tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
+		if (!tcinfo->handle_array)
+			return -ENOMEM;
+
+		tcinfo->array_len += 16;
+	}
+	tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
+	snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
+		 sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
+		 "%s",
+		 tb[TCA_KIND]
+			 ? libbpf_nla_getattr_str(tb[TCA_KIND])
+			 : "unknown");
+	tcinfo->used_len++;
+
+	return 0;
+}
+
+static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
+{
+	const struct bpf_filter_t *filter_info = cookie;
+
+	return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
+			      filter_info->devname, filter_info->ifindex);
+}
+
+static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
+			   struct ip_devname_ifindex *dev)
+{
+	struct bpf_filter_t filter_info;
+	struct bpf_tcinfo_t tcinfo;
+	int i, handle, ret = 0;
+
+	tcinfo.handle_array = NULL;
+	tcinfo.used_len = 0;
+	tcinfo.array_len = 0;
+
+	tcinfo.is_qdisc = false;
+	ret = netlink_get_class(sock, nl_pid, dev->ifindex,
+				dump_class_qdisc_nlmsg, &tcinfo);
+	if (ret)
+		goto out;
+
+	tcinfo.is_qdisc = true;
+	ret = netlink_get_qdisc(sock, nl_pid, dev->ifindex,
+				dump_class_qdisc_nlmsg, &tcinfo);
+	if (ret)
+		goto out;
+
+	filter_info.devname = dev->devname;
+	filter_info.ifindex = dev->ifindex;
+	for (i = 0; i < tcinfo.used_len; i++) {
+		filter_info.kind = tcinfo.handle_array[i].kind;
+		ret = netlink_get_filter(sock, nl_pid, dev->ifindex,
+					 tcinfo.handle_array[i].handle,
+					 dump_filter_nlmsg, &filter_info);
+		if (ret)
+			goto out;
+	}
+
+	/* root, ingress and egress handle */
+	handle = TC_H_ROOT;
+	filter_info.kind = "root";
+	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
+				 dump_filter_nlmsg, &filter_info);
+	if (ret)
+		goto out;
+
+	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
+	filter_info.kind = "clsact/ingress";
+	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
+				 dump_filter_nlmsg, &filter_info);
+	if (ret)
+		goto out;
+
+	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
+	filter_info.kind = "clsact/egress";
+	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
+				 dump_filter_nlmsg, &filter_info);
+	if (ret)
+		goto out;
+
+out:
+	free(tcinfo.handle_array);
+	return 0;
+}
+
+static int query_flow_dissector(struct bpf_attach_info *attach_info)
+{
+	__u32 attach_flags;
+	__u32 prog_ids[1];
+	__u32 prog_cnt;
+	int err;
+	int fd;
+
+	fd = open("/proc/self/ns/net", O_RDONLY);
+	if (fd < 0) {
+		p_err("can't open /proc/self/ns/net: %s",
+		      strerror(errno));
+		return -1;
+	}
+	prog_cnt = ARRAY_SIZE(prog_ids);
+	err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
+			     &attach_flags, prog_ids, &prog_cnt);
+	close(fd);
+	if (err) {
+		if (errno == EINVAL) {
+			/* Older kernel's don't support querying
+			 * flow dissector programs.
+			 */
+			errno = 0;
+			return 0;
+		}
+		p_err("can't query prog: %s", strerror(errno));
+		return -1;
+	}
+
+	if (prog_cnt == 1)
+		attach_info->flow_dissector_id = prog_ids[0];
+
+	return 0;
+}
+
+static int net_parse_dev(int *argc, char ***argv)
+{
+	int ifindex;
+
+	if (is_prefix(**argv, "dev")) {
+		NEXT_ARGP();
+
+		ifindex = if_nametoindex(**argv);
+		if (!ifindex)
+			p_err("invalid devname %s", **argv);
+
+		NEXT_ARGP();
+	} else {
+		p_err("expected 'dev', got: '%s'?", **argv);
+		return -1;
+	}
+
+	return ifindex;
+}
+
+static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,
+				int ifindex, bool overwrite)
+{
+	__u32 flags = 0;
+
+	if (!overwrite)
+		flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
+	if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC)
+		flags |= XDP_FLAGS_SKB_MODE;
+	if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER)
+		flags |= XDP_FLAGS_DRV_MODE;
+	if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)
+		flags |= XDP_FLAGS_HW_MODE;
+
+	return bpf_set_link_xdp_fd(ifindex, progfd, flags);
+}
+
+static int do_attach(int argc, char **argv)
+{
+	enum net_attach_type attach_type;
+	int progfd, ifindex, err = 0;
+	bool overwrite = false;
+
+	/* parse attach args */
+	if (!REQ_ARGS(5))
+		return -EINVAL;
+
+	attach_type = parse_attach_type(*argv);
+	if (attach_type == net_attach_type_size) {
+		p_err("invalid net attach/detach type: %s", *argv);
+		return -EINVAL;
+	}
+	NEXT_ARG();
+
+	progfd = prog_parse_fd(&argc, &argv);
+	if (progfd < 0)
+		return -EINVAL;
+
+	ifindex = net_parse_dev(&argc, &argv);
+	if (ifindex < 1) {
+		err = -EINVAL;
+		goto cleanup;
+	}
+
+	if (argc) {
+		if (is_prefix(*argv, "overwrite")) {
+			overwrite = true;
+		} else {
+			p_err("expected 'overwrite', got: '%s'?", *argv);
+			err = -EINVAL;
+			goto cleanup;
+		}
+	}
+
+	/* attach xdp prog */
+	if (is_prefix("xdp", attach_type_strings[attach_type]))
+		err = do_attach_detach_xdp(progfd, attach_type, ifindex,
+					   overwrite);
+	if (err) {
+		p_err("interface %s attach failed: %s",
+		      attach_type_strings[attach_type], strerror(-err));
+		goto cleanup;
+	}
+
+	if (json_output)
+		jsonw_null(json_wtr);
+cleanup:
+	close(progfd);
+	return err;
+}
+
+static int do_detach(int argc, char **argv)
+{
+	enum net_attach_type attach_type;
+	int progfd, ifindex, err = 0;
+
+	/* parse detach args */
+	if (!REQ_ARGS(3))
+		return -EINVAL;
+
+	attach_type = parse_attach_type(*argv);
+	if (attach_type == net_attach_type_size) {
+		p_err("invalid net attach/detach type: %s", *argv);
+		return -EINVAL;
+	}
+	NEXT_ARG();
+
+	ifindex = net_parse_dev(&argc, &argv);
+	if (ifindex < 1)
+		return -EINVAL;
+
+	/* detach xdp prog */
+	progfd = -1;
+	if (is_prefix("xdp", attach_type_strings[attach_type]))
+		err = do_attach_detach_xdp(progfd, attach_type, ifindex, NULL);
+
+	if (err < 0) {
+		p_err("interface %s detach failed: %s",
+		      attach_type_strings[attach_type], strerror(-err));
+		return err;
+	}
+
+	if (json_output)
+		jsonw_null(json_wtr);
+
+	return 0;
+}
+
+static int do_show(int argc, char **argv)
+{
+	struct bpf_attach_info attach_info = {};
+	int i, sock, ret, filter_idx = -1;
+	struct bpf_netdev_t dev_array;
+	unsigned int nl_pid = 0;
+	char err_buf[256];
+
+	if (argc == 2) {
+		filter_idx = net_parse_dev(&argc, &argv);
+		if (filter_idx < 1)
+			return -1;
+	} else if (argc != 0) {
+		usage();
+	}
+
+	ret = query_flow_dissector(&attach_info);
+	if (ret)
+		return -1;
+
+	sock = netlink_open(&nl_pid);
+	if (sock < 0) {
+		fprintf(stderr, "failed to open netlink sock\n");
+		return -1;
+	}
+
+	dev_array.devices = NULL;
+	dev_array.used_len = 0;
+	dev_array.array_len = 0;
+	dev_array.filter_idx = filter_idx;
+
+	if (json_output)
+		jsonw_start_array(json_wtr);
+	NET_START_OBJECT;
+	NET_START_ARRAY("xdp", "%s:\n");
+	ret = netlink_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
+	NET_END_ARRAY("\n");
+
+	if (!ret) {
+		NET_START_ARRAY("tc", "%s:\n");
+		for (i = 0; i < dev_array.used_len; i++) {
+			ret = show_dev_tc_bpf(sock, nl_pid,
+					      &dev_array.devices[i]);
+			if (ret)
+				break;
+		}
+		NET_END_ARRAY("\n");
+	}
+
+	NET_START_ARRAY("flow_dissector", "%s:\n");
+	if (attach_info.flow_dissector_id > 0)
+		NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
+	NET_END_ARRAY("\n");
+
+	NET_END_OBJECT;
+	if (json_output)
+		jsonw_end_array(json_wtr);
+
+	if (ret) {
+		if (json_output)
+			jsonw_null(json_wtr);
+		libbpf_strerror(ret, err_buf, sizeof(err_buf));
+		fprintf(stderr, "Error: %s\n", err_buf);
+	}
+	free(dev_array.devices);
+	close(sock);
+	return ret;
+}
+
+static int do_help(int argc, char **argv)
+{
+	if (json_output) {
+		jsonw_null(json_wtr);
+		return 0;
+	}
+
+	fprintf(stderr,
+		"Usage: %1$s %2$s { show | list } [dev <devname>]\n"
+		"       %1$s %2$s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"
+		"       %1$s %2$s detach ATTACH_TYPE dev <devname>\n"
+		"       %1$s %2$s help\n"
+		"\n"
+		"       " HELP_SPEC_PROGRAM "\n"
+		"       ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n"
+		"\n"
+		"Note: Only xdp and tc attachments are supported now.\n"
+		"      For progs attached to cgroups, use \"bpftool cgroup\"\n"
+		"      to dump program attachments. For program types\n"
+		"      sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
+		"      consult iproute2.\n"
+		"",
+		bin_name, argv[-2]);
+
+	return 0;
+}
+
+static const struct cmd cmds[] = {
+	{ "show",	do_show },
+	{ "list",	do_show },
+	{ "attach",	do_attach },
+	{ "detach",	do_detach },
+	{ "help",	do_help },
+	{ 0 }
+};
+
+int do_net(int argc, char **argv)
+{
+	return cmd_select(cmds, argc, argv, do_help);
+}