text: // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
  // Copyright (c) 2021 Wenbo Zhang
  //
  // Based on tcprtt(8) from BCC by zhenwei pi.
  // 06-Aug-2021   Wenbo Zhang   Created this.
  #define _DEFAULT_SOURCE
  #include <arpa/inet.h>
  #include <argp.h>
  #include <stdio.h>
  #include <signal.h>
  #include <unistd.h>
  #include <time.h>
  #include <bpf/libbpf.h>
  #include <bpf/bpf.h>
  #include "tcprtt.h"
  #include "tcprtt.skel.h"
  #include "trace_helpers.h"
  
  static struct env {
  	__u16 lport;
  	__u16 rport;
  	__u32 laddr;
  	__u32 raddr;
  	bool milliseconds;
  	time_t duration;
  	time_t interval;
  	bool timestamp;
  	bool laddr_hist;
  	bool raddr_hist;
  	bool extended;
  	bool verbose;
  } env = {
  	.interval = 99999999,
  };
  
  static volatile bool exiting;
  
  const char *argp_program_version = "tcprtt 0.1";
  const char *argp_program_bug_address =
  	"https://github.com/iovisor/bcc/tree/master/libbpf-tools";
  const char argp_program_doc[] =
  "Summarize TCP RTT as a histogram.\n"
  "\n"
  "USAGE: \n"
  "\n"
  "EXAMPLES:\n"
  "    tcprtt            # summarize TCP RTT\n"
  "    tcprtt -i 1 -d 10 # print 1 second summaries, 10 times\n"
  "    tcprtt -m -T      # summarize in millisecond, and timestamps\n"
  "    tcprtt -p         # filter for local port\n"
  "    tcprtt -P         # filter for remote port\n"
  "    tcprtt -a         # filter for local address\n"
  "    tcprtt -A         # filter for remote address\n"
  "    tcprtt -b         # show sockets histogram by local address\n"
  "    tcprtt -B         # show sockets histogram by remote address\n"
  "    tcprtt -e         # show extension summary(average)\n";
  
  static const struct argp_option opts[] = {
  	{ "interval", 'i', "INTERVAL", 0, "summary interval, seconds" },
  	{ "duration", 'd', "DURATION", 0, "total duration of trace, seconds" },
  	{ "timestamp", 'T', NULL, 0, "include timestamp on output" },
  	{ "millisecond", 'm', NULL, 0, "millisecond histogram" },
  	{ "lport", 'p', "LPORT", 0, "filter for local port" },
  	{ "rport", 'P', "RPORT", 0, "filter for remote port" },
  	{ "laddr", 'a', "LADDR", 0, "filter for local address" },
  	{ "raddr", 'A', "RADDR", 0, "filter for remote address" },
  	{ "byladdr", 'b', NULL, 0,
  	  "show sockets histogram by local address" },
  	{ "byraddr", 'B', NULL, 0,
  	  "show sockets histogram by remote address" },
  	{ "extension", 'e', NULL, 0, "show extension summary(average)" },
  	{ "verbose", 'v', NULL, 0, "Verbose debug output" },
  	{ NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
  	{},
  };
  
  static error_t parse_arg(int key, char *arg, struct argp_state *state)
  {
  	struct in_addr addr;
  
  	switch (key) {
  	case 'h':
  		argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
  		break;
  	case 'v':
  		env.verbose = true;
  		break;
  	case 'i':
  		errno = 0;
  		env.interval = strtol(arg, NULL, 10);
  		if (errno || env.interval <= 0) {
  			fprintf(stderr, "invalid interval: %s\n", arg);
  			argp_usage(state);
  		}
  		break;
  	case 'd':
  		errno = 0;
  		env.duration = strtol(arg, NULL, 10);
  		if (errno || env.duration <= 0) {
  			fprintf(stderr, "invalid duration: %s\n", arg);
  			argp_usage(state);
  		}
  		break;
  	case 'T':
  		env.timestamp = true;
  		break;
  	case 'm':
  		env.milliseconds = true;
  		break;
  	case 'p':
  		errno = 0;
  		env.lport = strtoul(arg, NULL, 10);
  		if (errno) {
  			fprintf(stderr, "invalid lport: %s\n", arg);
  			argp_usage(state);
  		}
  		env.lport = htons(env.lport);
  		break;
  	case 'P':
  		errno = 0;
  		env.rport = strtoul(arg, NULL, 10);
  		if (errno) {
  			fprintf(stderr, "invalid rport: %s\n", arg);
  			argp_usage(state);
  		}
  		env.rport = htons(env.rport);
  		break;
  	case 'a':
  		if (inet_aton(arg, &addr) < 0) {
  			fprintf(stderr, "invalid local address: %s\n", arg);
  			argp_usage(state);
  		}
  		env.laddr = addr.s_addr;
  		break;
  	case 'A':
  		if (inet_aton(arg, &addr) < 0) {
  			fprintf(stderr, "invalid remote address: %s\n", arg);
  			argp_usage(state);
  		}
  		env.raddr = addr.s_addr;
  		break;
  	case 'b':
  		env.laddr_hist = true;
  		break;
  	case 'B':
  		env.raddr_hist = true;
  		break;
  	case 'e':
  		env.extended = true;
  		break;
  	default:
  		return ARGP_ERR_UNKNOWN;
  	}
  	return 0;
  }
  
  static int libbpf_print_fn(enum libbpf_print_level level,
  			   const char *format, va_list args)
  {
  	if (level == LIBBPF_DEBUG && !env.verbose)
  		return 0;
  	return vfprintf(stderr, format, args);
  }
  
  static void sig_handler(int sig)
  {
  	exiting = true;
  }
  
  static int print_map(struct bpf_map *map)
  {
  	const char *units = env.milliseconds ? "msecs" : "usecs";
  	__u64 lookup_key = -1, next_key;
  	int err, fd = bpf_map__fd(map);
  	struct hist hist;
  
  	while (!bpf_map_get_next_key(fd, &lookup_key, &next_key)) {
  		err = bpf_map_lookup_elem(fd, &next_key, &hist);
  		if (err < 0) {
  			fprintf(stderr, "failed to lookup infos: %d\n", err);
  			return -1;
  		}
  
  		struct in_addr addr = {.s_addr = next_key };
  		if (env.laddr_hist)
  			printf("Local Address = %s ", inet_ntoa(addr));
  		else if (env.raddr_hist)
  			printf("Remote Address = %s ", inet_ntoa(addr));
  		else
  			printf("All Addresses = ****** ");
  		if (env.extended)
  			printf("[AVG %llu]", hist.latency / hist.cnt);
  		printf("\n");
  		print_log2_hist(hist.slots, MAX_SLOTS, units);
  		lookup_key = next_key;
  	}
  
  	lookup_key = -1;
  	while (!bpf_map_get_next_key(fd, &lookup_key, &next_key)) {
  		err = bpf_map_delete_elem(fd, &next_key);
  		if (err < 0) {
  			fprintf(stderr, "failed to cleanup infos: %d\n", err);
  			return -1;
  		}
  		lookup_key = next_key;
  	}
  
  	return 0;
  }
  
  int main(int argc, char **argv)
  {
  	static const struct argp argp = {
  		.options = opts,
  		.parser = parse_arg,
  		.doc = argp_program_doc,
  	};
  	struct tcprtt_bpf *obj;
  	__u64 time_end = 0;
  	struct tm *tm;
  	char ts[32];
  	time_t t;
  	int err;
  
  	err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
  	if (err)
  		return err;
  
  	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
  	libbpf_set_print(libbpf_print_fn);
  
  	obj = tcprtt_bpf__open();
  	if (!obj) {
  		fprintf(stderr, "failed to open BPF object\n");
  		return 1;
  	}
  
  	obj->rodata->targ_laddr_hist = env.laddr_hist;
  	obj->rodata->targ_raddr_hist = env.raddr_hist;
  	obj->rodata->targ_show_ext = env.extended;
  	obj->rodata->targ_sport = env.lport;
  	obj->rodata->targ_dport = env.rport;
  	obj->rodata->targ_saddr = env.laddr;
  	obj->rodata->targ_daddr = env.raddr;
  	obj->rodata->targ_ms = env.milliseconds;
  
  	if (!fentry_exists("tcp_rcv_established", NULL))
  		bpf_program__set_autoload(obj->progs.tcp_rcv_kprobe, false);
  	else
  		bpf_program__set_autoload(obj->progs.tcp_rcv, false);
  
  	err = tcprtt_bpf__load(obj);
  	if (err) {
  		fprintf(stderr, "failed to load BPF object: %d\n", err);
  		goto cleanup;
  	}
  
  	err = tcprtt_bpf__attach(obj);
  	if (err) {
  		fprintf(stderr, "failed to attach BPF programs: %d\n", err);
  		goto cleanup;
  	}
  
  	signal(SIGINT, sig_handler);
  
  	printf("Tracing TCP RTT");
  	if (env.duration)
  		printf(" for %ld secs.\n", env.duration);
  	else
  		printf("... Hit Ctrl-C to end.\n");
  
  	/* setup duration */
  	if (env.duration)
  		time_end = get_ktime_ns() + env.duration * NSEC_PER_SEC;
  
  	/* main: poll */
  	while (1) {
  		sleep(env.interval);
  		printf("\n");
  
  		if (env.timestamp) {
  			time(&t);
  			tm = localtime(&t);
  			strftime(ts, sizeof(ts), "%H:%M:%S", tm);
  			printf("%-8s\n", ts);
  		}
  
  		err = print_map(obj->maps.hists);
  		if (err)
  			break;
  
  		if (env.duration && get_ktime_ns() > time_end)
  			goto cleanup;
  
  		if (exiting)
  			break;
  	}
  
  cleanup:
  	tcprtt_bpf__destroy(obj);
  	return err != 0;
  }
  