/*
 * tcp_metrics.c	"ip tcp_metrics/tcpmetrics"
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		version 2 as published by the Free Software Foundation;
 *
 * Authors:	Julian Anastasov <ja@ssi.bg>, August 2012
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <linux/if.h>

#include <linux/genetlink.h>
#include <linux/tcp_metrics.h>

#include "utils.h"
#include "ip_common.h"
#include "libgenl.h"

static void usage(void)
{
	fprintf(stderr,
		"Usage:	ip tcp_metrics/tcpmetrics { COMMAND | help }\n"
		"	ip tcp_metrics { show | flush } SELECTOR\n"
		"	ip tcp_metrics delete [ address ] ADDRESS\n"
		"SELECTOR := [ [ address ] PREFIX ]\n");
	exit(-1);
}

/* netlink socket */
static struct rtnl_handle grth = { .fd = -1 };
static int genl_family = -1;
static const double usec_per_sec = 1000000.;

#define TCPM_REQUEST(_req, _bufsiz, _cmd, _flags) \
	GENL_REQUEST(_req, _bufsiz, genl_family, 0, \
		     TCP_METRICS_GENL_VERSION, _cmd, _flags)

#define CMD_LIST	0x0001	/* list, lst, show		*/
#define CMD_DEL		0x0002	/* delete, remove		*/
#define CMD_FLUSH	0x0004	/* flush			*/

static const struct {
	const char *name;
	int	code;
} cmds[] = {
	{	"list",		CMD_LIST	},
	{	"lst",		CMD_LIST	},
	{	"show",		CMD_LIST	},
	{	"delete",	CMD_DEL		},
	{	"remove",	CMD_DEL		},
	{	"flush",	CMD_FLUSH	},
};

static const char *metric_name[TCP_METRIC_MAX + 1] = {
	[TCP_METRIC_RTT]		= "rtt",
	[TCP_METRIC_RTTVAR]		= "rttvar",
	[TCP_METRIC_SSTHRESH]		= "ssthresh",
	[TCP_METRIC_CWND]		= "cwnd",
	[TCP_METRIC_REORDERING]		= "reordering",
};

static struct {
	int flushed;
	char *flushb;
	int flushp;
	int flushe;
	int cmd;
	inet_prefix daddr;
	inet_prefix saddr;
} f;

static int flush_update(void)
{
	if (rtnl_send_check(&grth, f.flushb, f.flushp) < 0) {
		perror("Failed to send flush request\n");
		return -1;
	}
	f.flushp = 0;
	return 0;
}

static void print_tcp_metrics(struct rtattr *a)
{
	struct rtattr *m[TCP_METRIC_MAX + 1 + 1];
	unsigned long rtt = 0, rttvar = 0;
	int i;

	parse_rtattr_nested(m, TCP_METRIC_MAX + 1, a);

	for (i = 0; i < TCP_METRIC_MAX + 1; i++) {
		const char *name;
		__u32 val;
		SPRINT_BUF(b1);

		a = m[i + 1];
		if (!a)
			continue;

		val = rta_getattr_u32(a);

		switch (i) {
		case TCP_METRIC_RTT:
			if (!rtt)
				rtt = (val * 1000UL) >> 3;
			continue;
		case TCP_METRIC_RTTVAR:
			if (!rttvar)
				rttvar = (val * 1000UL) >> 2;
			continue;
		case TCP_METRIC_RTT_US:
			rtt = val >> 3;
			continue;

		case TCP_METRIC_RTTVAR_US:
			rttvar = val >> 2;
			continue;

		case TCP_METRIC_SSTHRESH:
		case TCP_METRIC_CWND:
		case TCP_METRIC_REORDERING:
			name = metric_name[i];
			break;

		default:
			snprintf(b1, sizeof(b1),
				 " metric_%d ", i);
			name = b1;
		}


		print_uint(PRINT_JSON, name, NULL, val);
		print_string(PRINT_FP, NULL, " %s ", name);
		print_uint(PRINT_FP, NULL, "%u", val);
	}

	if (rtt) {
		print_float(PRINT_JSON, "rtt", NULL,
			    (double)rtt / usec_per_sec);
		print_u64(PRINT_FP, NULL,
			   " rtt %luus", rtt);
	}
	if (rttvar) {
		print_float(PRINT_JSON, "rttvar", NULL,
			    (double) rttvar / usec_per_sec);
		print_u64(PRINT_FP, NULL,
			   " rttvar %luus", rttvar);
	}
}

static int process_msg(struct nlmsghdr *n, void *arg)
{
	FILE *fp = (FILE *) arg;
	struct genlmsghdr *ghdr;
	struct rtattr *attrs[TCP_METRICS_ATTR_MAX + 1], *a;
	const char *h;
	int len = n->nlmsg_len;
	inet_prefix daddr, saddr;
	int atype, stype;

	if (n->nlmsg_type != genl_family)
		return -1;

	len -= NLMSG_LENGTH(GENL_HDRLEN);
	if (len < 0)
		return -1;

	ghdr = NLMSG_DATA(n);
	if (ghdr->cmd != TCP_METRICS_CMD_GET)
		return 0;

	parse_rtattr(attrs, TCP_METRICS_ATTR_MAX, (void *) ghdr + GENL_HDRLEN,
		     len);

	if (attrs[TCP_METRICS_ATTR_ADDR_IPV4]) {
		if (f.daddr.family && f.daddr.family != AF_INET)
			return 0;
		a = attrs[TCP_METRICS_ATTR_ADDR_IPV4];
		daddr.family = AF_INET;
		atype = TCP_METRICS_ATTR_ADDR_IPV4;
	} else if (attrs[TCP_METRICS_ATTR_ADDR_IPV6]) {
		if (f.daddr.family && f.daddr.family != AF_INET6)
			return 0;
		a = attrs[TCP_METRICS_ATTR_ADDR_IPV6];
		daddr.family = AF_INET6;
		atype = TCP_METRICS_ATTR_ADDR_IPV6;
	} else {
		return 0;
	}

	if (get_addr_rta(&daddr, a, daddr.family))
		return 0;

	if (f.daddr.family && f.daddr.bitlen >= 0 &&
	    inet_addr_match(&daddr, &f.daddr, f.daddr.bitlen))
		return 0;

	if (attrs[TCP_METRICS_ATTR_SADDR_IPV4]) {
		if (f.saddr.family && f.saddr.family != AF_INET)
			return 0;
		a = attrs[TCP_METRICS_ATTR_SADDR_IPV4];
		saddr.family = AF_INET;
		stype = TCP_METRICS_ATTR_SADDR_IPV4;
	} else if (attrs[TCP_METRICS_ATTR_SADDR_IPV6]) {
		if (f.saddr.family && f.saddr.family != AF_INET6)
			return 0;
		a = attrs[TCP_METRICS_ATTR_SADDR_IPV6];
		saddr.family = AF_INET6;
		stype = TCP_METRICS_ATTR_SADDR_IPV6;
	} else {
		saddr.family = AF_UNSPEC;
		stype = 0;
	}

	/* Only get/check for the source-address if the kernel supports it. */
	if (saddr.family) {
		if (get_addr_rta(&saddr, a, saddr.family))
			return 0;

		if (f.saddr.family && f.saddr.bitlen >= 0 &&
		    inet_addr_match(&saddr, &f.saddr, f.saddr.bitlen))
			return 0;
	}

	if (f.flushb) {
		struct nlmsghdr *fn;

		TCPM_REQUEST(req2, 128, TCP_METRICS_CMD_DEL, NLM_F_REQUEST);

		addattr_l(&req2.n, sizeof(req2), atype, daddr.data,
			  daddr.bytelen);
		if (saddr.family)
			addattr_l(&req2.n, sizeof(req2), stype, saddr.data,
				  saddr.bytelen);

		if (NLMSG_ALIGN(f.flushp) + req2.n.nlmsg_len > f.flushe) {
			if (flush_update())
				return -1;
		}
		fn = (struct nlmsghdr *) (f.flushb + NLMSG_ALIGN(f.flushp));
		memcpy(fn, &req2.n, req2.n.nlmsg_len);
		fn->nlmsg_seq = ++grth.seq;
		f.flushp = (((char *) fn) + req2.n.nlmsg_len) - f.flushb;
		f.flushed++;
		if (show_stats < 2)
			return 0;
	}

	open_json_object(NULL);
	if (f.cmd & (CMD_DEL | CMD_FLUSH))
		print_bool(PRINT_ANY, "deleted", "Deleted ", true);

	h = format_host(daddr.family, daddr.bytelen, daddr.data);
	print_color_string(PRINT_ANY,
			   ifa_family_color(daddr.family),
			   "dst", "%s", h);

	a = attrs[TCP_METRICS_ATTR_AGE];
	if (a) {
		__u64 val = rta_getattr_u64(a);
		double age = val / 1000.;

		print_float(PRINT_ANY, "age",
			     " age %.03fsec", age);
	}

	a = attrs[TCP_METRICS_ATTR_TW_TS_STAMP];
	if (a) {
		__s32 val = (__s32) rta_getattr_u32(a);
		__u32 tsval;
		char tw_ts[64];

		a = attrs[TCP_METRICS_ATTR_TW_TSVAL];
		tsval = a ? rta_getattr_u32(a) : 0;
		snprintf(tw_ts, sizeof(tw_ts),
			 "%u/%d", tsval, val);
		print_string(PRINT_ANY, "tw_ts_stamp",
		     " tw_ts %s ago", tw_ts);
	}

	if (attrs[TCP_METRICS_ATTR_VALS])
		print_tcp_metrics(attrs[TCP_METRICS_ATTR_VALS]);

	a = attrs[TCP_METRICS_ATTR_FOPEN_MSS];
	if (a) {
		print_uint(PRINT_ANY, "fopen_miss", " fo_mss %u",
			   rta_getattr_u16(a));
	}

	a = attrs[TCP_METRICS_ATTR_FOPEN_SYN_DROPS];
	if (a) {
		__u16 syn_loss = rta_getattr_u16(a);
		double ts;

		a = attrs[TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS];
		ts = a ? rta_getattr_u64(a) : 0;

		print_uint(PRINT_ANY, "fopen_syn_drops",
			   " fo_syn_drops %u", syn_loss);
		print_float(PRINT_ANY, "fopen_syn_drop_ts",
			     "/%.03fusec ago",
			     ts / 1000000.);
	}

	a = attrs[TCP_METRICS_ATTR_FOPEN_COOKIE];
	if (a) {
		char cookie[32 + 1];
		unsigned char *ptr = RTA_DATA(a);
		int i, max = RTA_PAYLOAD(a);

		if (max > 16)
			max = 16;
		cookie[0] = 0;
		for (i = 0; i < max; i++)
			sprintf(cookie + i + i, "%02x", ptr[i]);

		print_string(PRINT_ANY, "fo_cookie",
			     " fo_cookie %s", cookie);
	}

	if (saddr.family) {
		const char *src;

		src = format_host(saddr.family, saddr.bytelen, saddr.data);
		print_string(PRINT_ANY, "source",
			     " source %s", src);
	}

	print_string(PRINT_FP, NULL, "\n", "");
	close_json_object();
	fflush(fp);
	return 0;
}

static int tcpm_do_cmd(int cmd, int argc, char **argv)
{
	TCPM_REQUEST(req, 1024, TCP_METRICS_CMD_GET, NLM_F_REQUEST);
	struct nlmsghdr *answer;
	int atype = -1, stype = -1;
	int ack;

	memset(&f, 0, sizeof(f));
	f.daddr.bitlen = -1;
	f.daddr.family = preferred_family;
	f.saddr.bitlen = -1;
	f.saddr.family = preferred_family;

	switch (preferred_family) {
	case AF_UNSPEC:
	case AF_INET:
	case AF_INET6:
		break;
	default:
		fprintf(stderr, "Unsupported protocol family: %d\n", preferred_family);
		return -1;
	}

	for (; argc > 0; argc--, argv++) {
		if (strcmp(*argv, "src") == 0 ||
		    strcmp(*argv, "source") == 0) {
			char *who = *argv;

			NEXT_ARG();
			if (matches(*argv, "help") == 0)
				usage();
			if (f.saddr.bitlen >= 0)
				duparg2(who, *argv);

			get_prefix(&f.saddr, *argv, preferred_family);
			if (f.saddr.bytelen && f.saddr.bytelen * 8 == f.saddr.bitlen) {
				if (f.saddr.family == AF_INET)
					stype = TCP_METRICS_ATTR_SADDR_IPV4;
				else if (f.saddr.family == AF_INET6)
					stype = TCP_METRICS_ATTR_SADDR_IPV6;
			}

			if (stype < 0) {
				fprintf(stderr, "Error: a specific IP address is expected rather than \"%s\"\n",
					*argv);
				return -1;
			}
		} else {
			char *who = "address";

			if (strcmp(*argv, "addr") == 0 ||
			    strcmp(*argv, "address") == 0) {
				who = *argv;
				NEXT_ARG();
			}
			if (matches(*argv, "help") == 0)
				usage();
			if (f.daddr.bitlen >= 0)
				duparg2(who, *argv);

			get_prefix(&f.daddr, *argv, preferred_family);
			if (f.daddr.bytelen && f.daddr.bytelen * 8 == f.daddr.bitlen) {
				if (f.daddr.family == AF_INET)
					atype = TCP_METRICS_ATTR_ADDR_IPV4;
				else if (f.daddr.family == AF_INET6)
					atype = TCP_METRICS_ATTR_ADDR_IPV6;
			}
			if ((CMD_DEL & cmd) && atype < 0) {
				fprintf(stderr, "Error: a specific IP address is expected rather than \"%s\"\n",
					*argv);
				return -1;
			}
		}
		argc--; argv++;
	}

	if (cmd == CMD_DEL && atype < 0)
		missarg("address");

	/* flush for exact address ? Single del */
	if (cmd == CMD_FLUSH && atype >= 0)
		cmd = CMD_DEL;

	/* flush for all addresses ? Single del without address */
	if (cmd == CMD_FLUSH && f.daddr.bitlen <= 0 &&
	    f.saddr.bitlen <= 0 && preferred_family == AF_UNSPEC) {
		cmd = CMD_DEL;
		req.g.cmd = TCP_METRICS_CMD_DEL;
		ack = 1;
	} else if (cmd == CMD_DEL) {
		req.g.cmd = TCP_METRICS_CMD_DEL;
		ack = 1;
	} else {	/* CMD_FLUSH, CMD_LIST */
		ack = 0;
	}

	if (genl_init_handle(&grth, TCP_METRICS_GENL_NAME, &genl_family))
		exit(1);
	req.n.nlmsg_type = genl_family;

	if (!(cmd & CMD_FLUSH) && (atype >= 0 || (cmd & CMD_DEL))) {
		if (ack)
			req.n.nlmsg_flags |= NLM_F_ACK;
		if (atype >= 0)
			addattr_l(&req.n, sizeof(req), atype, &f.daddr.data,
				  f.daddr.bytelen);
		if (stype >= 0)
			addattr_l(&req.n, sizeof(req), stype, &f.saddr.data,
				  f.saddr.bytelen);
	} else {
		req.n.nlmsg_flags |= NLM_F_DUMP;
	}

	f.cmd = cmd;
	if (cmd & CMD_FLUSH) {
		int round = 0;
		char flushb[4096-512];

		f.flushb = flushb;
		f.flushp = 0;
		f.flushe = sizeof(flushb);

		for (;;) {
			req.n.nlmsg_seq = grth.dump = ++grth.seq;
			if (rtnl_send(&grth, &req, req.n.nlmsg_len) < 0) {
				perror("Failed to send flush request");
				exit(1);
			}
			f.flushed = 0;
			if (rtnl_dump_filter(&grth, process_msg, stdout) < 0) {
				fprintf(stderr, "Flush terminated\n");
				exit(1);
			}
			if (f.flushed == 0) {
				if (round == 0) {
					fprintf(stderr, "Nothing to flush.\n");
				} else if (show_stats)
					printf("*** Flush is complete after %d round%s ***\n",
					       round, round > 1 ? "s" : "");
				fflush(stdout);
				return 0;
			}
			round++;
			if (flush_update() < 0)
				exit(1);
			if (show_stats) {
				printf("\n*** Round %d, deleting %d entries ***\n",
				       round, f.flushed);
				fflush(stdout);
			}
		}
		return 0;
	}

	if (ack) {
		if (rtnl_talk(&grth, &req.n, NULL) < 0)
			return -2;
	} else if (atype >= 0) {
		if (rtnl_talk(&grth, &req.n, &answer) < 0)
			return -2;
		if (process_msg(answer, stdout) < 0) {
			fprintf(stderr, "Dump terminated\n");
			exit(1);
		}
		free(answer);
	} else {
		req.n.nlmsg_seq = grth.dump = ++grth.seq;
		if (rtnl_send(&grth, &req, req.n.nlmsg_len) < 0) {
			perror("Failed to send dump request");
			exit(1);
		}

		new_json_obj(json);
		if (rtnl_dump_filter(&grth, process_msg, stdout) < 0) {
			fprintf(stderr, "Dump terminated\n");
			exit(1);
		}
		delete_json_obj();
	}
	return 0;
}

int do_tcp_metrics(int argc, char **argv)
{
	int i;

	if (argc < 1)
		return tcpm_do_cmd(CMD_LIST, 0, NULL);
	for (i = 0; i < ARRAY_SIZE(cmds); i++) {
		if (matches(argv[0], cmds[i].name) == 0)
			return tcpm_do_cmd(cmds[i].code, argc-1, argv+1);
	}
	if (matches(argv[0], "help") == 0)
		usage();

	fprintf(stderr, "Command \"%s\" is unknown, try \"ip tcp_metrics help\".\n",
			*argv);
	exit(-1);
}