Linux debugging

Check our new training course

Linux debugging, tracing, profiling & perf. analysis

Check our new training course
with Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
/* vi: set sw=4 ts=4: */
/*
 * Mini netstat implementation(s) for busybox
 * based in part on the netstat implementation from net-tools.
 *
 * Copyright (C) 2002 by Bart Visscher <magick@linux-fan.com>
 *
 * 2002-04-20
 * IPV6 support added by Bart Visscher <magick@linux-fan.com>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"
#include "inet_common.h"

enum {
	OPT_extended = 0x4,
	OPT_showroute = 0x100,
	OPT_widedisplay = 0x200 * ENABLE_FEATURE_NETSTAT_WIDE,
};
# define NETSTAT_OPTS "laentuwxr"USE_FEATURE_NETSTAT_WIDE("W")

#define NETSTAT_CONNECTED 0x01
#define NETSTAT_LISTENING 0x02
#define NETSTAT_NUMERIC   0x04
/* Must match getopt32 option string */
#define NETSTAT_TCP       0x10
#define NETSTAT_UDP       0x20
#define NETSTAT_RAW       0x40
#define NETSTAT_UNIX      0x80
#define NETSTAT_ALLPROTO  (NETSTAT_TCP|NETSTAT_UDP|NETSTAT_RAW|NETSTAT_UNIX)

static smallint flags = NETSTAT_CONNECTED | NETSTAT_ALLPROTO;

enum {
	TCP_ESTABLISHED = 1,
	TCP_SYN_SENT,
	TCP_SYN_RECV,
	TCP_FIN_WAIT1,
	TCP_FIN_WAIT2,
	TCP_TIME_WAIT,
	TCP_CLOSE,
	TCP_CLOSE_WAIT,
	TCP_LAST_ACK,
	TCP_LISTEN,
	TCP_CLOSING /* now a valid state */
};

static const char *const tcp_state[] = {
	"",
	"ESTABLISHED",
	"SYN_SENT",
	"SYN_RECV",
	"FIN_WAIT1",
	"FIN_WAIT2",
	"TIME_WAIT",
	"CLOSE",
	"CLOSE_WAIT",
	"LAST_ACK",
	"LISTEN",
	"CLOSING"
};

typedef enum {
	SS_FREE = 0,     /* not allocated                */
	SS_UNCONNECTED,  /* unconnected to any socket    */
	SS_CONNECTING,   /* in process of connecting     */
	SS_CONNECTED,    /* connected to socket          */
	SS_DISCONNECTING /* in process of disconnecting  */
} socket_state;

#define SO_ACCEPTCON (1<<16)	/* performed a listen           */
#define SO_WAITDATA  (1<<17)	/* wait data to read            */
#define SO_NOSPACE   (1<<18)	/* no space to write            */

/* Standard printout size */
#define PRINT_IP_MAX_SIZE           23
#define PRINT_NET_CONN              "%s   %6ld %6ld %-23s %-23s %-12s\n"
#define PRINT_NET_CONN_HEADER       "\nProto Recv-Q Send-Q %-23s %-23s State\n"

/* When there are IPv6 connections the IPv6 addresses will be
 * truncated to none-recognition. The '-W' option makes the
 * address columns wide enough to accomodate for longest possible
 * IPv6 addresses, i.e. addresses of the form
 * xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:ddd.ddd.ddd.ddd
 */
#define PRINT_IP_MAX_SIZE_WIDE      51  /* INET6_ADDRSTRLEN + 5 for the port number */
#define PRINT_NET_CONN_WIDE         "%s   %6ld %6ld %-51s %-51s %-12s\n"
#define PRINT_NET_CONN_HEADER_WIDE  "\nProto Recv-Q Send-Q %-51s %-51s State\n"

static const char *net_conn_line = PRINT_NET_CONN;


#if ENABLE_FEATURE_IPV6
static void build_ipv6_addr(char* local_addr, struct sockaddr_in6* localaddr)
{
	char addr6[INET6_ADDRSTRLEN];
	struct in6_addr in6;

	sscanf(local_addr, "%08X%08X%08X%08X",
		   &in6.s6_addr32[0], &in6.s6_addr32[1],
		   &in6.s6_addr32[2], &in6.s6_addr32[3]);
	inet_ntop(AF_INET6, &in6, addr6, sizeof(addr6));
	inet_pton(AF_INET6, addr6, (struct sockaddr *) &localaddr->sin6_addr);

	localaddr->sin6_family = AF_INET6;
}
#endif

#if ENABLE_FEATURE_IPV6
static void build_ipv4_addr(char* local_addr, struct sockaddr_in6* localaddr)
#else
static void build_ipv4_addr(char* local_addr, struct sockaddr_in* localaddr)
#endif
{
	sscanf(local_addr, "%X",
		   &((struct sockaddr_in *) localaddr)->sin_addr.s_addr);
	((struct sockaddr *) localaddr)->sa_family = AF_INET;
}

static const char *get_sname(int port, const char *proto, int numeric)
{
	if (!port)
		return "*";
	if (!numeric) {
		struct servent *se = getservbyport(port, proto);
		if (se)
			return se->s_name;
	}
	/* hummm, we may return static buffer here!! */
	return itoa(ntohs(port));
}

static char *ip_port_str(struct sockaddr *addr, int port, const char *proto, int numeric)
{
	enum { salen = USE_FEATURE_IPV6(sizeof(struct sockaddr_in6)) SKIP_FEATURE_IPV6(sizeof(struct sockaddr_in)) };
	char *host, *host_port;

	/* Code which used "*" for INADDR_ANY is removed: it's ambiguous in IPv6,
	 * while "0.0.0.0" is not. */

	host = numeric ? xmalloc_sockaddr2dotted_noport(addr)
	               : xmalloc_sockaddr2host_noport(addr);

	host_port = xasprintf("%s:%s", host, get_sname(htons(port), proto, numeric));
	free(host);
	return host_port;
}

static void tcp_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	char more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
#if ENABLE_FEATURE_IPV6
	struct sockaddr_in6 localaddr, remaddr;
#else
	struct sockaddr_in localaddr, remaddr;
#endif
	unsigned long rxq, txq, time_len, retr, inode;

	if (lnr == 0)
		return;

	more[0] = '\0';
	num = sscanf(line,
			"%d: %64[0-9A-Fa-f]:%X %64[0-9A-Fa-f]:%X %X %lX:%lX %X:%lX %lX %d %d %ld %512s\n",
			&d, local_addr, &local_port,
			rem_addr, &rem_port, &state,
			&txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);

	if (strlen(local_addr) > 8) {
#if ENABLE_FEATURE_IPV6
		build_ipv6_addr(local_addr, &localaddr);
		build_ipv6_addr(rem_addr, &remaddr);
#endif
	} else {
		build_ipv4_addr(local_addr, &localaddr);
		build_ipv4_addr(rem_addr, &remaddr);
	}

	if (num < 10) {
		bb_error_msg("warning, got bogus tcp line");
		return;
	}

	if ((rem_port && (flags & NETSTAT_CONNECTED))
	 || (!rem_port && (flags & NETSTAT_LISTENING))
	) {
		char *l = ip_port_str(
				(struct sockaddr *) &localaddr, local_port,
				"tcp", flags & NETSTAT_NUMERIC);
		char *r = ip_port_str(
				(struct sockaddr *) &remaddr, rem_port,
				"tcp", flags & NETSTAT_NUMERIC);
		printf(net_conn_line,
			"tcp", rxq, txq, l, r, tcp_state[state]);
		free(l);
		free(r);
	}
}

static void udp_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	const char *state_str;
	char more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
#if ENABLE_FEATURE_IPV6
	struct sockaddr_in6 localaddr, remaddr;
#else
	struct sockaddr_in localaddr, remaddr;
#endif
	unsigned long rxq, txq, time_len, retr, inode;

	if (lnr == 0)
		return;

	more[0] = '\0';
	num = sscanf(line,
			"%d: %64[0-9A-Fa-f]:%X %64[0-9A-Fa-f]:%X %X %lX:%lX %X:%lX %lX %d %d %ld %512s\n",
			&d, local_addr, &local_port,
			rem_addr, &rem_port, &state,
			&txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);

	if (strlen(local_addr) > 8) {
#if ENABLE_FEATURE_IPV6
		/* Demangle what the kernel gives us */
		build_ipv6_addr(local_addr, &localaddr);
		build_ipv6_addr(rem_addr, &remaddr);
#endif
	} else {
		build_ipv4_addr(local_addr, &localaddr);
		build_ipv4_addr(rem_addr, &remaddr);
	}

	if (num < 10) {
		bb_error_msg("warning, got bogus udp line");
		return;
	}
	switch (state) {
		case TCP_ESTABLISHED:
			state_str = "ESTABLISHED";
			break;
		case TCP_CLOSE:
			state_str = "";
			break;
		default:
			state_str = "UNKNOWN";
			break;
	}

#if ENABLE_FEATURE_IPV6
# define notnull(A) ( \
	( (A.sin6_family == AF_INET6)                               \
	  && (A.sin6_addr.s6_addr32[0] | A.sin6_addr.s6_addr32[1] | \
	      A.sin6_addr.s6_addr32[2] | A.sin6_addr.s6_addr32[3])  \
	) || (                                                      \
	  (A.sin6_family == AF_INET)                                \
	  && ((struct sockaddr_in*)&A)->sin_addr.s_addr             \
	)                                                           \
)
#else
# define notnull(A) (A.sin_addr.s_addr)
#endif
	{
		int have_remaddr = notnull(remaddr);
		if ((have_remaddr && (flags & NETSTAT_CONNECTED))
		 || (!have_remaddr && (flags & NETSTAT_LISTENING))
		) {
			char *l = ip_port_str(
				(struct sockaddr *) &localaddr, local_port,
				"udp", flags & NETSTAT_NUMERIC);
			char *r = ip_port_str(
				(struct sockaddr *) &remaddr, rem_port,
				"udp", flags & NETSTAT_NUMERIC);
			printf(net_conn_line,
				"udp", rxq, txq, l, r, state_str);
			free(l);
			free(r);
		}
	}
}

static void raw_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	char more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
#if ENABLE_FEATURE_IPV6
	struct sockaddr_in6 localaddr, remaddr;
#else
	struct sockaddr_in localaddr, remaddr;
#endif
	unsigned long rxq, txq, time_len, retr, inode;

	if (lnr == 0)
		return;

	more[0] = '\0';
	num = sscanf(line,
			"%d: %64[0-9A-Fa-f]:%X %64[0-9A-Fa-f]:%X %X %lX:%lX %X:%lX %lX %d %d %ld %512s\n",
			&d, local_addr, &local_port,
			rem_addr, &rem_port, &state,
			&txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);

	if (strlen(local_addr) > 8) {
#if ENABLE_FEATURE_IPV6
		build_ipv6_addr(local_addr, &localaddr);
		build_ipv6_addr(rem_addr, &remaddr);
#endif
	} else {
		build_ipv4_addr(local_addr, &localaddr);
		build_ipv4_addr(rem_addr, &remaddr);
	}

	if (num < 10) {
		bb_error_msg("warning, got bogus raw line");
		return;
	}

	{
		int have_remaddr = notnull(remaddr);
		if ((have_remaddr && (flags & NETSTAT_CONNECTED))
		 || (!have_remaddr && (flags & NETSTAT_LISTENING))
		) {
			char *l = ip_port_str(
				(struct sockaddr *) &localaddr, local_port,
				"raw", flags & NETSTAT_NUMERIC);
			char *r = ip_port_str(
				(struct sockaddr *) &remaddr, rem_port,
				"raw", flags & NETSTAT_NUMERIC);
			printf(net_conn_line,
				"raw", rxq, txq, l, r, itoa(state));
			free(l);
			free(r);
		}
	}
}

static void unix_do_one(int nr, const char *line)
{
	static smallint has_inode = 0;

	char path[PATH_MAX], ss_flags[32];
	const char *ss_proto, *ss_state, *ss_type;
	int num, state, type, inode;
	void *d;
	unsigned long refcnt, proto, unix_flags;

	if (nr == 0) {
		if (strstr(line, "Inode"))
			has_inode = 1;
		return;
	}
	path[0] = '\0';
	num = sscanf(line, "%p: %lX %lX %lX %X %X %d %s",
			&d, &refcnt, &proto, &unix_flags, &type, &state, &inode, path);
	if (num < 6) {
		bb_error_msg("warning, got bogus unix line");
		return;
	}
	if (!has_inode)
		sprintf(path, "%d", inode);

	if ((flags & (NETSTAT_LISTENING|NETSTAT_CONNECTED)) != (NETSTAT_LISTENING|NETSTAT_CONNECTED)) {
		if ((state == SS_UNCONNECTED) && (unix_flags & SO_ACCEPTCON)) {
			if (!(flags & NETSTAT_LISTENING))
				return;
		} else {
			if (!(flags & NETSTAT_CONNECTED))
				return;
		}
	}

	switch (proto) {
		case 0:
			ss_proto = "unix";
			break;
		default:
			ss_proto = "??";
	}

	switch (type) {
		case SOCK_STREAM:
			ss_type = "STREAM";
			break;
		case SOCK_DGRAM:
			ss_type = "DGRAM";
			break;
		case SOCK_RAW:
			ss_type = "RAW";
			break;
		case SOCK_RDM:
			ss_type = "RDM";
			break;
		case SOCK_SEQPACKET:
			ss_type = "SEQPACKET";
			break;
		default:
			ss_type = "UNKNOWN";
	}

	switch (state) {
		case SS_FREE:
			ss_state = "FREE";
			break;
		case SS_UNCONNECTED:
			/*
			 * Unconnected sockets may be listening
			 * for something.
			 */
			if (unix_flags & SO_ACCEPTCON) {
				ss_state = "LISTENING";
			} else {
				ss_state = "";
			}
			break;
		case SS_CONNECTING:
			ss_state = "CONNECTING";
			break;
		case SS_CONNECTED:
			ss_state = "CONNECTED";
			break;
		case SS_DISCONNECTING:
			ss_state = "DISCONNECTING";
			break;
		default:
			ss_state = "UNKNOWN";
	}

	strcpy(ss_flags, "[ ");
	if (unix_flags & SO_ACCEPTCON)
		strcat(ss_flags, "ACC ");
	if (unix_flags & SO_WAITDATA)
		strcat(ss_flags, "W ");
	if (unix_flags & SO_NOSPACE)
		strcat(ss_flags, "N ");
	strcat(ss_flags, "]");

	printf("%-5s %-6ld %-11s %-10s %-13s ",
		   ss_proto, refcnt, ss_flags, ss_type, ss_state);
	if (has_inode)
		printf("%-6d ", inode);
	else
		printf("-      ");
	puts(path);
}

#define _PATH_PROCNET_UDP "/proc/net/udp"
#define _PATH_PROCNET_UDP6 "/proc/net/udp6"
#define _PATH_PROCNET_TCP "/proc/net/tcp"
#define _PATH_PROCNET_TCP6 "/proc/net/tcp6"
#define _PATH_PROCNET_RAW "/proc/net/raw"
#define _PATH_PROCNET_RAW6 "/proc/net/raw6"
#define _PATH_PROCNET_UNIX "/proc/net/unix"

static void do_info(const char *file, const char *name, void (*proc)(int, const char *))
{
	int lnr = 0;
	FILE *procinfo;

	procinfo = fopen(file, "r");
	if (procinfo == NULL) {
		if (errno != ENOENT) {
			bb_simple_perror_msg(file);
		} else {
			bb_error_msg("no support for '%s' on this system", name);
		}
		return;
	}
	do {
		char *buffer = xmalloc_fgets(procinfo);
		if (buffer) {
			(proc)(lnr++, buffer);
			free(buffer);
		}
	} while (!feof(procinfo));
	fclose(procinfo);
}

/*
 * Our main function.
 */

int netstat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int netstat_main(int argc, char **argv)
{
	const char *net_conn_line_header = PRINT_NET_CONN_HEADER;
	unsigned opt;
#if ENABLE_FEATURE_IPV6
	smallint inet = 1;
	smallint inet6 = 1;
#else
	enum { inet = 1, inet6 = 0 };
#endif

	/* Option string must match NETSTAT_xxx constants */
	opt = getopt32(argv, NETSTAT_OPTS);
	if (opt & 0x1) { // -l
		flags &= ~NETSTAT_CONNECTED;
		flags |= NETSTAT_LISTENING;
	}
	if (opt & 0x2) flags |= NETSTAT_LISTENING | NETSTAT_CONNECTED; // -a
	//if (opt & 0x4) // -e
	if (opt & 0x8) flags |= NETSTAT_NUMERIC; // -n
	//if (opt & 0x10) // -t: NETSTAT_TCP
	//if (opt & 0x20) // -u: NETSTAT_UDP
	//if (opt & 0x40) // -w: NETSTAT_RAW
	//if (opt & 0x80) // -x: NETSTAT_UNIX
	if (opt & OPT_showroute) { // -r
#if ENABLE_ROUTE
		bb_displayroutes(flags & NETSTAT_NUMERIC, !(opt & OPT_extended));
		return 0;
#else
		bb_show_usage();
#endif
	}

	if (opt & OPT_widedisplay) { // -W
		net_conn_line = PRINT_NET_CONN_WIDE;
		net_conn_line_header = PRINT_NET_CONN_HEADER_WIDE;
	}

	opt &= NETSTAT_ALLPROTO;
	if (opt) {
		flags &= ~NETSTAT_ALLPROTO;
		flags |= opt;
	}
	if (flags & (NETSTAT_TCP|NETSTAT_UDP|NETSTAT_RAW)) {
		printf("Active Internet connections ");	/* xxx */

		if ((flags & (NETSTAT_LISTENING|NETSTAT_CONNECTED)) == (NETSTAT_LISTENING|NETSTAT_CONNECTED))
			printf("(servers and established)");
		else if (flags & NETSTAT_LISTENING)
			printf("(only servers)");
		else
			printf("(w/o servers)");
		printf(net_conn_line_header, "Local Address", "Foreign Address");
	}
	if (inet && flags & NETSTAT_TCP)
		do_info(_PATH_PROCNET_TCP, "AF INET (tcp)", tcp_do_one);
#if ENABLE_FEATURE_IPV6
	if (inet6 && flags & NETSTAT_TCP)
		do_info(_PATH_PROCNET_TCP6, "AF INET6 (tcp)", tcp_do_one);
#endif
	if (inet && flags & NETSTAT_UDP)
		do_info(_PATH_PROCNET_UDP, "AF INET (udp)", udp_do_one);
#if ENABLE_FEATURE_IPV6
	if (inet6 && flags & NETSTAT_UDP)
		do_info(_PATH_PROCNET_UDP6, "AF INET6 (udp)", udp_do_one);
#endif
	if (inet && flags & NETSTAT_RAW)
		do_info(_PATH_PROCNET_RAW, "AF INET (raw)", raw_do_one);
#if ENABLE_FEATURE_IPV6
	if (inet6 && flags & NETSTAT_RAW)
		do_info(_PATH_PROCNET_RAW6, "AF INET6 (raw)", raw_do_one);
#endif
	if (flags & NETSTAT_UNIX) {
		printf("Active UNIX domain sockets ");
		if ((flags & (NETSTAT_LISTENING|NETSTAT_CONNECTED)) == (NETSTAT_LISTENING|NETSTAT_CONNECTED))
			printf("(servers and established)");
		else if (flags & NETSTAT_LISTENING)
			printf("(only servers)");
		else
			printf("(w/o servers)");
		printf("\nProto RefCnt Flags       Type       State         I-Node Path\n");
		do_info(_PATH_PROCNET_UNIX, "AF UNIX", unix_do_one);
	}
	return 0;
}