Add -M option to nc(1), which makes it print the TCP connection

statistics obtained with stats(3) in JSON format to standard error.

Reviewed by:	allanjude, thj, cem (earlier version)
Tested by:	thj
MFC after:	2 weeks
Relnotes:	yes
Sponsored by:	Klara Inc.
Differential Revision:	https://reviews.freebsd.org/D21324
This commit is contained in:
Edward Tomasz Napierala 2019-12-14 10:53:52 +00:00
parent c62ff2800b
commit 1e62ecedf2
3 changed files with 114 additions and 7 deletions

View File

@ -27,7 +27,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd September 26, 2015
.Dd August 20, 2019
.Dt NC 1
.Os
.Sh NAME
@ -36,7 +36,7 @@
.Sh SYNOPSIS
.Nm nc
.Bk -words
.Op Fl 46DdEFhklNnrStUuvz
.Op Fl 46DdEFhklMNnrStUuvz
.Op Fl e Ar IPsec_policy
.Op Fl I Ar length
.Op Fl i Ar interval
@ -170,6 +170,12 @@ options.
Additionally, any timeouts specified with the
.Fl w
option are ignored.
.It Fl M
Collect per-connection TCP statistics using the
.Xr stats 3
framework and print them in JSON format to
.Xr stderr 4
after the connection is closed.
.It Fl N
.Xr shutdown 2
the network socket after EOF on the input.

View File

@ -33,10 +33,16 @@
* *Hobbit* <hobbit@avian.org>.
*/
#include <errno.h>
#include <stdio.h>
#include <sys/arb.h>
#include <sys/limits.h>
#include <sys/types.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/qmath.h>
#include <sys/stats.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/un.h>
@ -50,7 +56,6 @@
#include <arpa/telnet.h>
#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <fcntl.h>
#include <limits.h>
@ -58,7 +63,6 @@
#include <poll.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
@ -85,6 +89,7 @@ int Fflag; /* fdpass sock to stdout */
unsigned int iflag; /* Interval Flag */
int kflag; /* More than one connect */
int lflag; /* Bind to local port */
int FreeBSD_Mflag; /* Measure using stats(3) */
int Nflag; /* shutdown() network socket */
int nflag; /* Don't do name look up */
int FreeBSD_Oflag; /* Do not use TCP options */
@ -123,6 +128,8 @@ int udptest(int);
int unix_bind(char *);
int unix_connect(char *);
int unix_listen(char *);
void FreeBSD_stats_setup(int);
void FreeBSD_stats_print(int);
void set_common_sockopts(int, int);
int map_tos(char *, int *);
void report_connect(const struct sockaddr *, socklen_t);
@ -167,7 +174,7 @@ main(int argc, char *argv[])
signal(SIGPIPE, SIG_IGN);
while ((ch = getopt_long(argc, argv,
"46DdEe:FhI:i:klNnoO:P:p:rSs:tT:UuV:vw:X:x:z",
"46DdEe:FhI:i:klMNnoO:P:p:rSs:tT:UuV:vw:X:x:z",
longopts, NULL)) != -1) {
switch (ch) {
case '4':
@ -224,6 +231,13 @@ main(int argc, char *argv[])
case 'l':
lflag = 1;
break;
case 'M':
#ifndef WITH_STATS
errx(1, "-M requires stats(3) support");
#else
FreeBSD_Mflag = 1;
#endif
break;
case 'N':
Nflag = 1;
break;
@ -451,6 +465,8 @@ main(int argc, char *argv[])
if (vflag)
report_connect((struct sockaddr *)&cliaddr, len);
if (FreeBSD_Mflag)
FreeBSD_stats_setup(connfd);
readwrite(connfd);
close(connfd);
}
@ -801,6 +817,7 @@ readwrite(int net_fd)
unsigned char stdinbuf[BUFSIZE];
size_t stdinbufpos = 0;
int n, num_fds;
int stats_printed = 0;
ssize_t ret;
/* don't read from stdin if requested */
@ -827,17 +844,23 @@ readwrite(int net_fd)
/* both inputs are gone, buffers are empty, we are done */
if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1
&& stdinbufpos == 0 && netinbufpos == 0) {
if (FreeBSD_Mflag && !stats_printed)
FreeBSD_stats_print(net_fd);
close(net_fd);
return;
}
/* both outputs are gone, we can't continue */
if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) {
if (FreeBSD_Mflag && !stats_printed)
FreeBSD_stats_print(net_fd);
close(net_fd);
return;
}
/* listen and net in gone, queues empty, done */
if (lflag && pfd[POLL_NETIN].fd == -1
&& stdinbufpos == 0 && netinbufpos == 0) {
if (FreeBSD_Mflag && !stats_printed)
FreeBSD_stats_print(net_fd);
close(net_fd);
return;
}
@ -858,8 +881,11 @@ readwrite(int net_fd)
}
/* timeout happened */
if (num_fds == 0)
if (num_fds == 0) {
if (FreeBSD_Mflag)
FreeBSD_stats_print(net_fd);
return;
}
/* treat socket error conditions */
for (n = 0; n < 4; n++) {
@ -961,8 +987,13 @@ readwrite(int net_fd)
/* stdin gone and queue empty? */
if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) {
if (pfd[POLL_NETOUT].fd != -1 && Nflag)
if (pfd[POLL_NETOUT].fd != -1 && Nflag) {
if (FreeBSD_Mflag) {
FreeBSD_stats_print(net_fd);
stats_printed = 1;
}
shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
}
pfd[POLL_NETOUT].fd = -1;
}
/* net in gone and queue empty? */
@ -1180,6 +1211,67 @@ udptest(int s)
return (ret);
}
void
FreeBSD_stats_setup(int s)
{
if (setsockopt(s, IPPROTO_TCP, TCP_STATS,
&FreeBSD_Mflag, sizeof(FreeBSD_Mflag)) == -1) {
if (errno == EOPNOTSUPP) {
warnx("getsockopt(TCP_STATS) failed; "
"kernel built without \"options STATS\"?");
}
err(1, "enable TCP_STATS gathering");
}
}
void
FreeBSD_stats_print(int s)
{
#ifdef WITH_STATS
struct statsblob *statsb;
struct sbuf *sb;
socklen_t sockoptlen;
int error;
/*
* This usleep is a workaround for TCP_STATS reporting
* incorrect values for TXPB.
*/
usleep(100000);
sockoptlen = 2048;
statsb = malloc(sockoptlen);
if (statsb == NULL)
err(1, "malloc");
error = getsockopt(s, IPPROTO_TCP, TCP_STATS, statsb, &sockoptlen);
if (error != 0) {
if (errno == EOVERFLOW && statsb->cursz > sockoptlen) {
/* Retry with a larger size. */
sockoptlen = statsb->cursz;
statsb = realloc(statsb, sockoptlen);
if (statsb == NULL)
err(1, "realloc");
error = getsockopt(s, IPPROTO_TCP, TCP_STATS,
statsb, &sockoptlen);
}
if (error != 0)
err(1, "getsockopt");
}
sb = sbuf_new_auto();
error = stats_blob_tostr(statsb, sb, SB_STRFMT_JSON, SB_TOSTR_META);
if (error != 0)
errc(1, error, "stats_blob_tostr");
error = sbuf_finish(sb);
if (error != 0)
err(1, "sbuf_finish");
fprintf(stderr, "%s\n", sbuf_data(sb));
#endif
}
void
set_common_sockopts(int s, int af)
{
@ -1224,6 +1316,8 @@ set_common_sockopts(int s, int af)
&FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1)
err(1, "disable TCP options");
}
if (FreeBSD_Mflag)
FreeBSD_stats_setup(s);
#ifdef IPSEC
if (ipsec_policy[0] != NULL)
add_ipsec_policy(s, af, ipsec_policy[0]);

View File

@ -1,5 +1,7 @@
# $FreeBSD$
.include <src.opts.mk>
.PATH: ${SRCTOP}/contrib/netcat
PROG= nc
@ -8,6 +10,11 @@ SRCS= netcat.c atomicio.c socks.c
CFLAGS+=-DIPSEC
LIBADD= ipsec
.if ${MK_STATS} != "no" && !defined(RESCUE)
LIBADD+= sbuf stats
CFLAGS+= -DWITH_STATS
.endif
WARNS?= 2
.include <bsd.prog.mk>