/* 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 "busybox.h"
#include "inet_common.h"

#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 int 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            */

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

static void snprint_ip_port(char *ip_port, int size, struct sockaddr *addr, int port, const char *proto, int numeric)
{
	const char *port_name;

#if ENABLE_FEATURE_IPV6
	if (addr->sa_family == AF_INET6) {
		INET6_rresolve(ip_port, size, (struct sockaddr_in6 *)addr,
			(numeric & NETSTAT_NUMERIC) ? 0x0fff : 0);
	} else
#endif
	{
		INET_rresolve(ip_port, size, (struct sockaddr_in *)addr,
			0x4000 | ((numeric & NETSTAT_NUMERIC) ? 0x0fff : 0),
			0xffffffff);
	}
	port_name = get_sname(htons(port), proto, numeric);
	if ((strlen(ip_port) + strlen(port_name)) > 22)
		ip_port[22 - strlen(port_name)] = '\0';
	ip_port += strlen(ip_port);
	strcat(ip_port, ":");
	strcat(ip_port, port_name);
}

static void tcp_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;
	char addr6[INET6_ADDRSTRLEN];
	struct in6_addr in6;
#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
		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);
		sscanf(rem_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 *) &remaddr.sin6_addr);
		localaddr.sin6_family = AF_INET6;
		remaddr.sin6_family = AF_INET6;
#endif
	} else {
		sscanf(local_addr, "%X",
			   &((struct sockaddr_in *) &localaddr)->sin_addr.s_addr);
		sscanf(rem_addr, "%X",
			   &((struct sockaddr_in *) &remaddr)->sin_addr.s_addr);
		((struct sockaddr *) &localaddr)->sa_family = AF_INET;
		((struct sockaddr *) &remaddr)->sa_family = AF_INET;
	}

	if (num < 10) {
		bb_error_msg("warning, got bogus tcp line");
		return;
	}
	state_str = tcp_state[state];
	if ((rem_port && (flags & NETSTAT_CONNECTED))
	 || (!rem_port && (flags & NETSTAT_LISTENING))
	) {
		snprint_ip_port(local_addr, sizeof(local_addr),
						(struct sockaddr *) &localaddr, local_port,
						"tcp", flags & NETSTAT_NUMERIC);

		snprint_ip_port(rem_addr, sizeof(rem_addr),
						(struct sockaddr *) &remaddr, rem_port,
						"tcp", flags & NETSTAT_NUMERIC);

		printf("tcp   %6ld %6ld %-23s %-23s %-12s\n",
			   rxq, txq, local_addr, rem_addr, state_str);
	}
}

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;
	char addr6[INET6_ADDRSTRLEN];
	struct in6_addr in6;
#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 */
		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);
		sscanf(rem_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 *) &remaddr.sin6_addr);
		localaddr.sin6_family = AF_INET6;
		remaddr.sin6_family = AF_INET6;
#endif
	} else {
		sscanf(local_addr, "%X",
			   &((struct sockaddr_in *) &localaddr)->sin_addr.s_addr);
		sscanf(rem_addr, "%X",
			   &((struct sockaddr_in *) &remaddr)->sin_addr.s_addr);
		((struct sockaddr *) &localaddr)->sa_family = AF_INET;
		((struct sockaddr *) &remaddr)->sa_family = AF_INET;
	}

	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
	if ((notnull(remaddr) && (flags & NETSTAT_CONNECTED))
	 || (!notnull(remaddr) && (flags & NETSTAT_LISTENING))
	) {
		snprint_ip_port(local_addr, sizeof(local_addr),
						(struct sockaddr *) &localaddr, local_port,
						"udp", flags & NETSTAT_NUMERIC);

		snprint_ip_port(rem_addr, sizeof(rem_addr),
						(struct sockaddr *) &remaddr, rem_port,
						"udp", flags & NETSTAT_NUMERIC);

		printf("udp   %6ld %6ld %-23s %-23s %-12s\n",
			   rxq, txq, local_addr, rem_addr, state_str);
	}
}

static void raw_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	char *state_str, more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
#if ENABLE_FEATURE_IPV6
	struct sockaddr_in6 localaddr, remaddr;
	char addr6[INET6_ADDRSTRLEN];
	struct in6_addr in6;
#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
		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);
		sscanf(rem_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 *) &remaddr.sin6_addr);
		localaddr.sin6_family = AF_INET6;
		remaddr.sin6_family = AF_INET6;
#endif
	} else {
		sscanf(local_addr, "%X",
			   &((struct sockaddr_in *) &localaddr)->sin_addr.s_addr);
		sscanf(rem_addr, "%X",
			   &((struct sockaddr_in *) &remaddr)->sin_addr.s_addr);
		((struct sockaddr *) &localaddr)->sa_family = AF_INET;
		((struct sockaddr *) &remaddr)->sa_family = AF_INET;
	}

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

#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
	if ((notnull(remaddr) && (flags & NETSTAT_CONNECTED))
	 || (!notnull(remaddr) && (flags & NETSTAT_LISTENING))
	) {
		snprint_ip_port(local_addr, sizeof(local_addr),
						(struct sockaddr *) &localaddr, local_port,
						"raw", flags & NETSTAT_NUMERIC);

		snprint_ip_port(rem_addr, sizeof(rem_addr),
						(struct sockaddr *) &remaddr, rem_port,
						"raw", flags & NETSTAT_NUMERIC);

		printf("raw   %6ld %6ld %-23s %-23s %-12s\n",
			   rxq, txq, local_addr, rem_addr, state_str);
	}
}

#define HAS_INODE 1

static void unix_do_one(int nr, const char *line)
{
	static int has = 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 |= HAS_INODE;
		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 & HAS_INODE))
		snprintf(path,sizeof(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 & 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_perror_msg("%s", 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);
int netstat_main(int argc, char **argv)
{
	enum {
		OPT_extended = 0x4,
		OPT_showroute = 0x100,
	};
	unsigned opt;
#if ENABLE_FEATURE_IPV6
	int inet = 1;
	int inet6 = 1;
#else
	enum { inet = 1, inet6 = 0 };
#endif

	/* Option string must match NETSTAT_xxx constants */
	opt = getopt32(argc, argv, "laentuwxr");
	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_error_msg_and_die("-r (display routing table) is not compiled in");
#endif
	}

	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("\nProto Recv-Q Send-Q Local Address           Foreign Address         State\n");
	}
	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;
}