1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
  2// Copyright (C) 2018 Facebook
  3
  4#define _GNU_SOURCE
  5#include <errno.h>
  6#include <fcntl.h>
  7#include <stdlib.h>
  8#include <string.h>
  9#include <time.h>
 10#include <unistd.h>
 11#include <bpf/bpf.h>
 12#include <bpf/libbpf.h>
 13#include <net/if.h>
 
 14#include <linux/rtnetlink.h>
 15#include <linux/socket.h>
 16#include <linux/tc_act/tc_bpf.h>
 17#include <sys/socket.h>
 18#include <sys/stat.h>
 19#include <sys/types.h>
 20
 21#include "bpf/nlattr.h"
 
 22#include "main.h"
 23#include "netlink_dumper.h"
 24
 25#ifndef SOL_NETLINK
 26#define SOL_NETLINK 270
 27#endif
 28
 29struct ip_devname_ifindex {
 30	char	devname[64];
 31	int	ifindex;
 32};
 33
 34struct bpf_netdev_t {
 35	struct ip_devname_ifindex *devices;
 36	int	used_len;
 37	int	array_len;
 38	int	filter_idx;
 39};
 40
 41struct tc_kind_handle {
 42	char	kind[64];
 43	int	handle;
 44};
 45
 46struct bpf_tcinfo_t {
 47	struct tc_kind_handle	*handle_array;
 48	int			used_len;
 49	int			array_len;
 50	bool			is_qdisc;
 51};
 52
 53struct bpf_filter_t {
 54	const char	*kind;
 55	const char	*devname;
 56	int		ifindex;
 57};
 58
 59struct bpf_attach_info {
 60	__u32 flow_dissector_id;
 61};
 62
 63enum net_attach_type {
 64	NET_ATTACH_TYPE_XDP,
 65	NET_ATTACH_TYPE_XDP_GENERIC,
 66	NET_ATTACH_TYPE_XDP_DRIVER,
 67	NET_ATTACH_TYPE_XDP_OFFLOAD,
 68};
 69
 70static const char * const attach_type_strings[] = {
 71	[NET_ATTACH_TYPE_XDP]		= "xdp",
 72	[NET_ATTACH_TYPE_XDP_GENERIC]	= "xdpgeneric",
 73	[NET_ATTACH_TYPE_XDP_DRIVER]	= "xdpdrv",
 74	[NET_ATTACH_TYPE_XDP_OFFLOAD]	= "xdpoffload",
 75};
 76
 77const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);
 78
 79static enum net_attach_type parse_attach_type(const char *str)
 80{
 81	enum net_attach_type type;
 82
 83	for (type = 0; type < net_attach_type_size; type++) {
 84		if (attach_type_strings[type] &&
 85		    is_prefix(str, attach_type_strings[type]))
 86			return type;
 87	}
 88
 89	return net_attach_type_size;
 90}
 91
 92typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
 93
 94typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
 95
 96static int netlink_open(__u32 *nl_pid)
 97{
 98	struct sockaddr_nl sa;
 99	socklen_t addrlen;
100	int one = 1, ret;
101	int sock;
102
103	memset(&sa, 0, sizeof(sa));
104	sa.nl_family = AF_NETLINK;
105
106	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
107	if (sock < 0)
108		return -errno;
109
110	if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
111		       &one, sizeof(one)) < 0) {
112		p_err("Netlink error reporting not supported");
113	}
114
115	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
116		ret = -errno;
117		goto cleanup;
118	}
119
120	addrlen = sizeof(sa);
121	if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
122		ret = -errno;
123		goto cleanup;
124	}
125
126	if (addrlen != sizeof(sa)) {
127		ret = -LIBBPF_ERRNO__INTERNAL;
128		goto cleanup;
129	}
130
131	*nl_pid = sa.nl_pid;
132	return sock;
133
134cleanup:
135	close(sock);
136	return ret;
137}
138
139static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
140			    __dump_nlmsg_t _fn, dump_nlmsg_t fn,
141			    void *cookie)
142{
143	bool multipart = true;
144	struct nlmsgerr *err;
145	struct nlmsghdr *nh;
146	char buf[4096];
147	int len, ret;
148
149	while (multipart) {
150		multipart = false;
151		len = recv(sock, buf, sizeof(buf), 0);
152		if (len < 0) {
153			ret = -errno;
154			goto done;
155		}
156
157		if (len == 0)
158			break;
159
160		for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, (unsigned int)len);
161		     nh = NLMSG_NEXT(nh, len)) {
162			if (nh->nlmsg_pid != nl_pid) {
163				ret = -LIBBPF_ERRNO__WRNGPID;
164				goto done;
165			}
166			if (nh->nlmsg_seq != seq) {
167				ret = -LIBBPF_ERRNO__INVSEQ;
168				goto done;
169			}
170			if (nh->nlmsg_flags & NLM_F_MULTI)
171				multipart = true;
172			switch (nh->nlmsg_type) {
173			case NLMSG_ERROR:
174				err = (struct nlmsgerr *)NLMSG_DATA(nh);
175				if (!err->error)
176					continue;
177				ret = err->error;
178				libbpf_nla_dump_errormsg(nh);
179				goto done;
180			case NLMSG_DONE:
181				return 0;
182			default:
183				break;
184			}
185			if (_fn) {
186				ret = _fn(nh, fn, cookie);
187				if (ret)
188					return ret;
189			}
190		}
191	}
192	ret = 0;
193done:
194	return ret;
195}
196
197static int __dump_class_nlmsg(struct nlmsghdr *nlh,
198			      dump_nlmsg_t dump_class_nlmsg,
199			      void *cookie)
200{
201	struct nlattr *tb[TCA_MAX + 1], *attr;
202	struct tcmsg *t = NLMSG_DATA(nlh);
203	int len;
204
205	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
206	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
207	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
208		return -LIBBPF_ERRNO__NLPARSE;
209
210	return dump_class_nlmsg(cookie, t, tb);
211}
212
213static int netlink_get_class(int sock, unsigned int nl_pid, int ifindex,
214			     dump_nlmsg_t dump_class_nlmsg, void *cookie)
215{
216	struct {
217		struct nlmsghdr nlh;
218		struct tcmsg t;
219	} req = {
220		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
221		.nlh.nlmsg_type = RTM_GETTCLASS,
222		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
223		.t.tcm_family = AF_UNSPEC,
224		.t.tcm_ifindex = ifindex,
225	};
226	int seq = time(NULL);
227
228	req.nlh.nlmsg_seq = seq;
229	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
230		return -errno;
231
232	return netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
233			    dump_class_nlmsg, cookie);
234}
235
236static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
237			      dump_nlmsg_t dump_qdisc_nlmsg,
238			      void *cookie)
239{
240	struct nlattr *tb[TCA_MAX + 1], *attr;
241	struct tcmsg *t = NLMSG_DATA(nlh);
242	int len;
243
244	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
245	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
246	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
247		return -LIBBPF_ERRNO__NLPARSE;
248
249	return dump_qdisc_nlmsg(cookie, t, tb);
250}
251
252static int netlink_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
253			     dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
254{
255	struct {
256		struct nlmsghdr nlh;
257		struct tcmsg t;
258	} req = {
259		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
260		.nlh.nlmsg_type = RTM_GETQDISC,
261		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
262		.t.tcm_family = AF_UNSPEC,
263		.t.tcm_ifindex = ifindex,
264	};
265	int seq = time(NULL);
266
267	req.nlh.nlmsg_seq = seq;
268	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
269		return -errno;
270
271	return netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
272			    dump_qdisc_nlmsg, cookie);
273}
274
275static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
276			       dump_nlmsg_t dump_filter_nlmsg,
277			       void *cookie)
278{
279	struct nlattr *tb[TCA_MAX + 1], *attr;
280	struct tcmsg *t = NLMSG_DATA(nlh);
281	int len;
282
283	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
284	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
285	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
286		return -LIBBPF_ERRNO__NLPARSE;
287
288	return dump_filter_nlmsg(cookie, t, tb);
289}
290
291static int netlink_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
292			      dump_nlmsg_t dump_filter_nlmsg, void *cookie)
293{
294	struct {
295		struct nlmsghdr nlh;
296		struct tcmsg t;
297	} req = {
298		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
299		.nlh.nlmsg_type = RTM_GETTFILTER,
300		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
301		.t.tcm_family = AF_UNSPEC,
302		.t.tcm_ifindex = ifindex,
303		.t.tcm_parent = handle,
304	};
305	int seq = time(NULL);
306
307	req.nlh.nlmsg_seq = seq;
308	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
309		return -errno;
310
311	return netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
312			    dump_filter_nlmsg, cookie);
313}
314
315static int __dump_link_nlmsg(struct nlmsghdr *nlh,
316			     dump_nlmsg_t dump_link_nlmsg, void *cookie)
317{
318	struct nlattr *tb[IFLA_MAX + 1], *attr;
319	struct ifinfomsg *ifi = NLMSG_DATA(nlh);
320	int len;
321
322	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
323	attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
324	if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
325		return -LIBBPF_ERRNO__NLPARSE;
326
327	return dump_link_nlmsg(cookie, ifi, tb);
328}
329
330static int netlink_get_link(int sock, unsigned int nl_pid,
331			    dump_nlmsg_t dump_link_nlmsg, void *cookie)
332{
333	struct {
334		struct nlmsghdr nlh;
335		struct ifinfomsg ifm;
336	} req = {
337		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
338		.nlh.nlmsg_type = RTM_GETLINK,
339		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
340		.ifm.ifi_family = AF_PACKET,
341	};
342	int seq = time(NULL);
343
344	req.nlh.nlmsg_seq = seq;
345	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
346		return -errno;
347
348	return netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
349			    dump_link_nlmsg, cookie);
350}
351
352static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
353{
354	struct bpf_netdev_t *netinfo = cookie;
355	struct ifinfomsg *ifinfo = msg;
356
357	if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
358		return 0;
359
360	if (netinfo->used_len == netinfo->array_len) {
361		netinfo->devices = realloc(netinfo->devices,
362			(netinfo->array_len + 16) *
363			sizeof(struct ip_devname_ifindex));
364		if (!netinfo->devices)
365			return -ENOMEM;
366
367		netinfo->array_len += 16;
368	}
369	netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
370	snprintf(netinfo->devices[netinfo->used_len].devname,
371		 sizeof(netinfo->devices[netinfo->used_len].devname),
372		 "%s",
373		 tb[IFLA_IFNAME]
374			 ? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
375			 : "");
376	netinfo->used_len++;
377
378	return do_xdp_dump(ifinfo, tb);
379}
380
381static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
382{
383	struct bpf_tcinfo_t *tcinfo = cookie;
384	struct tcmsg *info = msg;
385
386	if (tcinfo->is_qdisc) {
387		/* skip clsact qdisc */
388		if (tb[TCA_KIND] &&
389		    strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
390			return 0;
391		if (info->tcm_handle == 0)
392			return 0;
393	}
394
395	if (tcinfo->used_len == tcinfo->array_len) {
396		tcinfo->handle_array = realloc(tcinfo->handle_array,
397			(tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
398		if (!tcinfo->handle_array)
399			return -ENOMEM;
400
401		tcinfo->array_len += 16;
402	}
403	tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
404	snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
405		 sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
406		 "%s",
407		 tb[TCA_KIND]
408			 ? libbpf_nla_getattr_str(tb[TCA_KIND])
409			 : "unknown");
410	tcinfo->used_len++;
411
412	return 0;
413}
414
415static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
416{
417	const struct bpf_filter_t *filter_info = cookie;
418
419	return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
420			      filter_info->devname, filter_info->ifindex);
421}
422
423static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
424			   struct ip_devname_ifindex *dev)
425{
426	struct bpf_filter_t filter_info;
427	struct bpf_tcinfo_t tcinfo;
428	int i, handle, ret = 0;
429
430	tcinfo.handle_array = NULL;
431	tcinfo.used_len = 0;
432	tcinfo.array_len = 0;
433
434	tcinfo.is_qdisc = false;
435	ret = netlink_get_class(sock, nl_pid, dev->ifindex,
436				dump_class_qdisc_nlmsg, &tcinfo);
437	if (ret)
438		goto out;
439
440	tcinfo.is_qdisc = true;
441	ret = netlink_get_qdisc(sock, nl_pid, dev->ifindex,
442				dump_class_qdisc_nlmsg, &tcinfo);
443	if (ret)
444		goto out;
445
446	filter_info.devname = dev->devname;
447	filter_info.ifindex = dev->ifindex;
448	for (i = 0; i < tcinfo.used_len; i++) {
449		filter_info.kind = tcinfo.handle_array[i].kind;
450		ret = netlink_get_filter(sock, nl_pid, dev->ifindex,
451					 tcinfo.handle_array[i].handle,
452					 dump_filter_nlmsg, &filter_info);
453		if (ret)
454			goto out;
455	}
456
457	/* root, ingress and egress handle */
458	handle = TC_H_ROOT;
459	filter_info.kind = "root";
460	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
461				 dump_filter_nlmsg, &filter_info);
462	if (ret)
463		goto out;
464
465	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
466	filter_info.kind = "clsact/ingress";
467	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
468				 dump_filter_nlmsg, &filter_info);
469	if (ret)
470		goto out;
471
472	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
473	filter_info.kind = "clsact/egress";
474	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
475				 dump_filter_nlmsg, &filter_info);
476	if (ret)
477		goto out;
478
479out:
480	free(tcinfo.handle_array);
481	return 0;
482}
483
484static int query_flow_dissector(struct bpf_attach_info *attach_info)
485{
486	__u32 attach_flags;
487	__u32 prog_ids[1];
488	__u32 prog_cnt;
489	int err;
490	int fd;
491
492	fd = open("/proc/self/ns/net", O_RDONLY);
493	if (fd < 0) {
494		p_err("can't open /proc/self/ns/net: %s",
495		      strerror(errno));
496		return -1;
497	}
498	prog_cnt = ARRAY_SIZE(prog_ids);
499	err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
500			     &attach_flags, prog_ids, &prog_cnt);
501	close(fd);
502	if (err) {
503		if (errno == EINVAL) {
504			/* Older kernel's don't support querying
505			 * flow dissector programs.
506			 */
507			errno = 0;
508			return 0;
509		}
510		p_err("can't query prog: %s", strerror(errno));
511		return -1;
512	}
513
514	if (prog_cnt == 1)
515		attach_info->flow_dissector_id = prog_ids[0];
516
517	return 0;
518}
519
520static int net_parse_dev(int *argc, char ***argv)
521{
522	int ifindex;
523
524	if (is_prefix(**argv, "dev")) {
525		NEXT_ARGP();
526
527		ifindex = if_nametoindex(**argv);
528		if (!ifindex)
529			p_err("invalid devname %s", **argv);
530
531		NEXT_ARGP();
532	} else {
533		p_err("expected 'dev', got: '%s'?", **argv);
534		return -1;
535	}
536
537	return ifindex;
538}
539
540static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,
541				int ifindex, bool overwrite)
542{
543	__u32 flags = 0;
544
545	if (!overwrite)
546		flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
547	if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC)
548		flags |= XDP_FLAGS_SKB_MODE;
549	if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER)
550		flags |= XDP_FLAGS_DRV_MODE;
551	if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)
552		flags |= XDP_FLAGS_HW_MODE;
553
554	return bpf_set_link_xdp_fd(ifindex, progfd, flags);
555}
556
557static int do_attach(int argc, char **argv)
558{
559	enum net_attach_type attach_type;
560	int progfd, ifindex, err = 0;
561	bool overwrite = false;
562
563	/* parse attach args */
564	if (!REQ_ARGS(5))
565		return -EINVAL;
566
567	attach_type = parse_attach_type(*argv);
568	if (attach_type == net_attach_type_size) {
569		p_err("invalid net attach/detach type: %s", *argv);
570		return -EINVAL;
571	}
572	NEXT_ARG();
573
574	progfd = prog_parse_fd(&argc, &argv);
575	if (progfd < 0)
576		return -EINVAL;
577
578	ifindex = net_parse_dev(&argc, &argv);
579	if (ifindex < 1) {
580		err = -EINVAL;
581		goto cleanup;
582	}
583
584	if (argc) {
585		if (is_prefix(*argv, "overwrite")) {
586			overwrite = true;
587		} else {
588			p_err("expected 'overwrite', got: '%s'?", *argv);
589			err = -EINVAL;
590			goto cleanup;
591		}
592	}
593
594	/* attach xdp prog */
595	if (is_prefix("xdp", attach_type_strings[attach_type]))
596		err = do_attach_detach_xdp(progfd, attach_type, ifindex,
597					   overwrite);
598	if (err) {
 
599		p_err("interface %s attach failed: %s",
600		      attach_type_strings[attach_type], strerror(-err));
601		goto cleanup;
602	}
603
604	if (json_output)
605		jsonw_null(json_wtr);
606cleanup:
607	close(progfd);
608	return err;
609}
610
611static int do_detach(int argc, char **argv)
612{
613	enum net_attach_type attach_type;
614	int progfd, ifindex, err = 0;
615
616	/* parse detach args */
617	if (!REQ_ARGS(3))
618		return -EINVAL;
619
620	attach_type = parse_attach_type(*argv);
621	if (attach_type == net_attach_type_size) {
622		p_err("invalid net attach/detach type: %s", *argv);
623		return -EINVAL;
624	}
625	NEXT_ARG();
626
627	ifindex = net_parse_dev(&argc, &argv);
628	if (ifindex < 1)
629		return -EINVAL;
630
631	/* detach xdp prog */
632	progfd = -1;
633	if (is_prefix("xdp", attach_type_strings[attach_type]))
634		err = do_attach_detach_xdp(progfd, attach_type, ifindex, NULL);
635
636	if (err < 0) {
637		p_err("interface %s detach failed: %s",
638		      attach_type_strings[attach_type], strerror(-err));
639		return err;
640	}
641
642	if (json_output)
643		jsonw_null(json_wtr);
644
645	return 0;
646}
647
648static int do_show(int argc, char **argv)
649{
650	struct bpf_attach_info attach_info = {};
651	int i, sock, ret, filter_idx = -1;
652	struct bpf_netdev_t dev_array;
653	unsigned int nl_pid = 0;
654	char err_buf[256];
655
656	if (argc == 2) {
657		filter_idx = net_parse_dev(&argc, &argv);
658		if (filter_idx < 1)
659			return -1;
660	} else if (argc != 0) {
661		usage();
662	}
663
664	ret = query_flow_dissector(&attach_info);
665	if (ret)
666		return -1;
667
668	sock = netlink_open(&nl_pid);
669	if (sock < 0) {
670		fprintf(stderr, "failed to open netlink sock\n");
671		return -1;
672	}
673
674	dev_array.devices = NULL;
675	dev_array.used_len = 0;
676	dev_array.array_len = 0;
677	dev_array.filter_idx = filter_idx;
678
679	if (json_output)
680		jsonw_start_array(json_wtr);
681	NET_START_OBJECT;
682	NET_START_ARRAY("xdp", "%s:\n");
683	ret = netlink_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
684	NET_END_ARRAY("\n");
685
686	if (!ret) {
687		NET_START_ARRAY("tc", "%s:\n");
688		for (i = 0; i < dev_array.used_len; i++) {
689			ret = show_dev_tc_bpf(sock, nl_pid,
690					      &dev_array.devices[i]);
691			if (ret)
692				break;
693		}
694		NET_END_ARRAY("\n");
695	}
696
697	NET_START_ARRAY("flow_dissector", "%s:\n");
698	if (attach_info.flow_dissector_id > 0)
699		NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
700	NET_END_ARRAY("\n");
701
702	NET_END_OBJECT;
703	if (json_output)
704		jsonw_end_array(json_wtr);
705
706	if (ret) {
707		if (json_output)
708			jsonw_null(json_wtr);
709		libbpf_strerror(ret, err_buf, sizeof(err_buf));
710		fprintf(stderr, "Error: %s\n", err_buf);
711	}
712	free(dev_array.devices);
713	close(sock);
714	return ret;
715}
716
717static int do_help(int argc, char **argv)
718{
719	if (json_output) {
720		jsonw_null(json_wtr);
721		return 0;
722	}
723
724	fprintf(stderr,
725		"Usage: %1$s %2$s { show | list } [dev <devname>]\n"
726		"       %1$s %2$s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"
727		"       %1$s %2$s detach ATTACH_TYPE dev <devname>\n"
728		"       %1$s %2$s help\n"
729		"\n"
730		"       " HELP_SPEC_PROGRAM "\n"
731		"       ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n"
732		"\n"
733		"Note: Only xdp and tc attachments are supported now.\n"
734		"      For progs attached to cgroups, use \"bpftool cgroup\"\n"
735		"      to dump program attachments. For program types\n"
736		"      sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
737		"      consult iproute2.\n"
738		"",
739		bin_name, argv[-2]);
740
741	return 0;
742}
743
744static const struct cmd cmds[] = {
745	{ "show",	do_show },
746	{ "list",	do_show },
747	{ "attach",	do_attach },
748	{ "detach",	do_detach },
749	{ "help",	do_help },
750	{ 0 }
751};
752
753int do_net(int argc, char **argv)
754{
755	return cmd_select(cmds, argc, argv, do_help);
756}