2 files changed, 319 insertions, 56 deletions

diff --git a/usr.sbin/tcpdrop/tcpdrop.8 b/usr.sbin/tcpdrop/tcpdrop.8
index 5fd3a43e9506..b846257b79b4 100644
--- a/usr.sbin/tcpdrop/tcpdrop.8
+++ b/usr.sbin/tcpdrop/tcpdrop.8
@@ -1,5 +1,6 @@
 .\"	$OpenBSD: tcpdrop.8,v 1.5 2004/05/24 13:57:31 jmc Exp $
 .\"
+.\" Copyright (c) 2009 Juli Mallett <jmallett@FreeBSD.org>
 .\" Copyright (c) 2004 Markus Friedl <markus@openbsd.org>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
@@ -16,35 +17,58 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 21, 2004
+.Dd March 24, 2009
 .Dt TCPDROP 8
 .Os
 .Sh NAME
 .Nm tcpdrop
-.Nd drop a TCP connection
+.Nd drop TCP connections
 .Sh SYNOPSIS
 .Nm tcpdrop
-.Ar laddr
-.Ar lport
-.Ar faddr
-.Ar fport
+.Ar local-address
+.Ar local-port
+.Ar foreign-address
+.Ar foreign-port
+.Nm tcpdrop
+.Op Fl l
+.Fl a
 .Sh DESCRIPTION
 The
 .Nm
-command drops the TCP connection specified by the local address
-.Ar laddr ,
+command may be used to drop TCP connections from the command line.
+.Pp
+If
+.Fl a
+is specified then
+.Nm
+will attempt to drop all active connections.
+The
+.Fl l
+flag may be given to list the tcpdrop invocation to drop all active
+connections one at a time.
+.Pp
+If
+.Fl a
+is not specified then only the connection between the given local
+address
+.Ar local-address ,
 port
-.Ar lport
+.Ar local-port ,
 and the foreign address
-.Ar faddr ,
+.Ar foreign-address ,
 port
-.Ar fport .
-Addresses and ports can be specified by name or numeric value.
+.Ar foreign-port ,
+will be dropped.
+.Pp
+Addresses and ports may be specified by name or numeric value.
+Both IPv4 and IPv6 address formats are supported.
+.Nm
+in case of success or failure.
 .Sh EXIT STATUS
 .Ex -std
 .Sh EXAMPLES
 If a connection to
-.Xr httpd 8 Pq Pa ports/www/apache2
+.Xr httpd 8
 is causing congestion on a network link, one can drop the TCP session
 in charge:
 .Bd -literal -offset indent
@@ -57,8 +81,16 @@ The following command will drop the connection:
 .Bd -literal -offset indent
 # tcpdrop 192.168.5.41 80 192.168.5.1 26747
 .Ed
+.Pp
+The following command will drop all connections but those to or from
+port 22, the port used by
+.Xr sshd 8 :
+.Bd -literal -offset indent
+# tcpdrop -l -a | grep -vw 22 | sh
+.Ed
 .Sh SEE ALSO
 .Xr netstat 1 ,
 .Xr sockstat 1
 .Sh AUTHORS
 .An Markus Friedl Aq markus@openbsd.org
+.An Juli Mallett Aq jmallett@FreeBSD.org
diff --git a/usr.sbin/tcpdrop/tcpdrop.c b/usr.sbin/tcpdrop/tcpdrop.c
index 06ca0da84a0f..6aae85ccb4d1 100644
--- a/usr.sbin/tcpdrop/tcpdrop.c
+++ b/usr.sbin/tcpdrop/tcpdrop.c
@@ -1,6 +1,7 @@
 /* $OpenBSD: tcpdrop.c,v 1.4 2004/05/22 23:55:22 deraadt Exp $ */
 
 /*-
+ * Copyright (c) 2009 Juli Mallett <jmallett@FreeBSD.org>
  * Copyright (c) 2004 Markus Friedl <markus@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
@@ -21,15 +22,41 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/socketvar.h>
 #include <sys/sysctl.h>
 #include <netinet/in.h>
+
+#include <netinet/in_pcb.h>
+#define TCPSTATES
+#include <netinet/tcp_fsm.h>
 #include <netinet/tcp_var.h>
 
 #include <err.h>
 #include <netdb.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
+
+#define	TCPDROP_FOREIGN		0
+#define	TCPDROP_LOCAL		1
+
+struct host_service {
+	char hs_host[NI_MAXHOST];
+	char hs_service[NI_MAXSERV];
+};
+
+static bool tcpdrop_list_commands = false;
+
+static struct xinpgen *getxpcblist(const char *);
+static void sockinfo(const struct sockaddr *, struct host_service *);
+static bool tcpdrop(const struct sockaddr *, const struct sockaddr *);
+static bool tcpdropall(void);
+static bool tcpdropbyname(const char *, const char *, const char *,
+    const char *);
+static bool tcpdropconn(const struct in_conninfo *);
+static void usage(void);
 
 /*
  * Drop a tcp connection.
@@ -37,55 +64,259 @@ __FBSDID("$FreeBSD$");
 int
 main(int argc, char *argv[])
 {
-	struct addrinfo hints, *ail, *aif, *laddr, *faddr;
-	/* addrs[0] is a foreign socket, addrs[1] is a local one. */
-	struct sockaddr_storage addrs[2];
-	int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_DROP };
-	int gaierr, rval = 0;
-	char fhbuf[NI_MAXHOST], fsbuf[NI_MAXSERV], lhbuf[NI_MAXHOST],
-	    lsbuf[NI_MAXSERV];
+	bool dropall;
+	int ch;
+
+	dropall = false;
+
+	while ((ch = getopt(argc, argv, "al")) != -1) {
+		switch (ch) {
+		case 'a':
+			dropall = true;
+			break;
+		case 'l':
+			tcpdrop_list_commands = true;
+			break;
+		default:
+			usage();
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if (dropall) {
+		if (argc != 0)
+			usage();
+		if (!tcpdropall())
+			exit(1);
+		exit(0);
+	}
 
-	if (argc != 5) {
-		fprintf(stderr, "usage: tcpdrop laddr lport faddr fport\n");
+	if (argc != 4 || tcpdrop_list_commands)
+		usage();
+
+	if (!tcpdropbyname(argv[0], argv[1], argv[2], argv[3]))
 		exit(1);
+
+	exit(0);
+}
+
+static struct xinpgen *
+getxpcblist(const char *name)
+{
+	struct xinpgen *xinp;
+	size_t len;
+	int rv;
+
+	len = 0;
+	rv = sysctlbyname(name, NULL, &len, NULL, 0);
+	if (rv == -1)
+		err(1, "sysctlbyname %s", name);
+
+	if (len == 0)
+		errx(1, "%s is empty", name);
+
+	xinp = malloc(len);
+	if (xinp == NULL)
+		errx(1, "malloc failed");
+
+	rv = sysctlbyname(name, xinp, &len, NULL, 0);
+	if (rv == -1)
+		err(1, "sysctlbyname %s", name);
+
+	return (xinp);
+}
+
+static void
+sockinfo(const struct sockaddr *sa, struct host_service *hs)
+{
+	static const int flags = NI_NUMERICHOST | NI_NUMERICSERV;
+	int rv;
+
+	rv = getnameinfo(sa, sa->sa_len, hs->hs_host, sizeof hs->hs_host,
+	    hs->hs_service, sizeof hs->hs_service, flags);
+	if (rv == -1)
+		err(1, "getnameinfo");
+}
+
+static bool
+tcpdrop(const struct sockaddr *lsa, const struct sockaddr *fsa)
+{
+	struct host_service local, foreign;
+	struct sockaddr_storage addrs[2];
+	int rv;
+
+	memcpy(&addrs[TCPDROP_FOREIGN], fsa, fsa->sa_len);
+	memcpy(&addrs[TCPDROP_LOCAL], lsa, lsa->sa_len);
+
+	sockinfo(lsa, &local);
+	sockinfo(fsa, &foreign);
+
+	if (tcpdrop_list_commands) {
+		printf("tcpdrop %s %s %s %s\n", local.hs_host, local.hs_service,
+		    foreign.hs_host, foreign.hs_service);
+		return (true);
+	}
+
+	rv = sysctlbyname("net.inet.tcp.drop", NULL, NULL, &addrs,
+	    sizeof addrs);
+	if (rv == -1) {
+		warn("%s %s %s %s", local.hs_host, local.hs_service,
+		    foreign.hs_host, foreign.hs_service);
+		return (false);
+	}
+	printf("%s %s %s %s: dropped\n", local.hs_host, local.hs_service,
+	    foreign.hs_host, foreign.hs_service);
+	return (true);
+}
+
+static bool
+tcpdropall(void)
+{
+	struct xinpgen *head, *xinp;
+	struct xtcpcb *xpcb;
+	struct tcpcb *tp;
+	struct inpcb *inp;
+	bool ok;
+
+	ok = true;
+
+	head = getxpcblist("net.inet.tcp.pcblist");
+
+#define	XINP_NEXT(xinp)							\
+	((struct xinpgen *)((uintptr_t)(xinp) + (xinp)->xig_len))
+
+	for (xinp = XINP_NEXT(head); xinp->xig_len > sizeof *xinp;
+	    xinp = XINP_NEXT(xinp)) {
+		xpcb = (struct xtcpcb *)xinp;
+		tp = &xpcb->xt_tp;
+		inp = &xpcb->xt_inp;
+
+		/*
+		 * XXX
+		 * Check protocol, support just v4 or v6, etc.
+		 */
+
+		/* Ignore PCBs which were freed during copyout.  */
+		if (inp->inp_gencnt > head->xig_gen)
+			continue;
+
+		/* Skip listening sockets.  */
+		if (tp->t_state == TCPS_LISTEN)
+			continue;
+
+		if (!tcpdropconn(&inp->inp_inc))
+			ok = false;
 	}
-	memset(&hints, 0, sizeof(hints));
-	hints.ai_family = AF_UNSPEC;
-	hints.ai_socktype = SOCK_STREAM;
-	if ((gaierr = getaddrinfo(argv[1], argv[2], &hints, &laddr)) != 0)
-		errx(1, "%s port %s: %s", argv[1], argv[2],
-		    gai_strerror(gaierr));
-	if ((gaierr = getaddrinfo(argv[3], argv[4], &hints, &faddr)) != 0) {
-		freeaddrinfo(laddr);
-		errx(1, "%s port %s: %s", argv[3], argv[4],
-		    gai_strerror(gaierr));
+	free(head);
+
+	return (ok);
+}
+
+static bool
+tcpdropbyname(const char *lhost, const char *lport, const char *fhost,
+    const char *fport)
+{
+	static const struct addrinfo hints = {
+		/*
+		 * Look for streams in all domains.
+		 */
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = SOCK_STREAM,
+	};
+	struct addrinfo *ail, *local, *aif, *foreign;
+	int error;
+	bool ok, infamily;
+
+	error = getaddrinfo(lhost, lport, &hints, &local);
+	if (error != 0)
+		errx(1, "getaddrinfo: %s port %s: %s", lhost, lport,
+		    gai_strerror(error));
+
+	error = getaddrinfo(fhost, fport, &hints, &foreign);
+	if (error != 0) {
+		freeaddrinfo(local); /* XXX gratuitous */
+		errx(1, "getaddrinfo: %s port %s: %s", lhost, lport,
+		    gai_strerror(error));
 	}
-	for (ail = laddr; ail; ail = ail->ai_next) {
-		for (aif = faddr; aif; aif = aif->ai_next) {
+
+	ok = true;
+	infamily = false;
+
+	/*
+	 * Try every combination of local and foreign address pairs.
+	 */
+	for (ail = local; ail != NULL; ail = ail->ai_next) {
+		for (aif = foreign; aif != NULL; aif = aif->ai_next) {
 			if (ail->ai_family != aif->ai_family)
 				continue;
-			memcpy(&addrs[0], aif->ai_addr, aif->ai_addrlen);
-			memcpy(&addrs[1], ail->ai_addr, ail->ai_addrlen);
-			if (getnameinfo(aif->ai_addr, aif->ai_addrlen,
-			    fhbuf, sizeof(fhbuf),
-			    fsbuf, sizeof(fsbuf),
-			    NI_NUMERICHOST | NI_NUMERICSERV) == -1)
-				err(1, "getnameinfo");
-			if (getnameinfo(ail->ai_addr, ail->ai_addrlen,
-			    lhbuf, sizeof(lhbuf),
-			    lsbuf, sizeof(lsbuf),
-			    NI_NUMERICHOST | NI_NUMERICSERV) == -1)
-				err(1, "getnameinfo");
-			if (sysctl(mib, sizeof (mib) / sizeof (int), NULL,
-			    NULL, &addrs, sizeof(addrs)) == -1) {
-				rval = 1;
-				warn("%s %s %s %s", lhbuf, lsbuf, fhbuf, fsbuf);
-			} else
-				printf("%s %s %s %s: dropped\n",
-				    lhbuf, lsbuf, fhbuf, fsbuf);
+			infamily = true;
+			if (!tcpdrop(ail->ai_addr, aif->ai_addr))
+				ok = false;
 		}
 	}
-	freeaddrinfo(laddr);
-	freeaddrinfo(faddr);
-	exit(rval);
+
+	if (!infamily) {
+		warnx("%s %s %s %s: different address families", lhost, lport,
+		    fhost, fport);
+		ok = false;
+	}
+
+	freeaddrinfo(local);
+	freeaddrinfo(foreign);
+
+	return (ok);
+}
+
+static bool
+tcpdropconn(const struct in_conninfo *inc)
+{
+	struct sockaddr *local, *foreign;
+	struct sockaddr_in6 sin6[2];
+	struct sockaddr_in sin4[2];
+
+	if ((inc->inc_flags & INC_ISIPV6) != 0) {
+		memset(sin6, 0, sizeof sin6);
+
+		sin6[TCPDROP_LOCAL].sin6_len = sizeof sin6[TCPDROP_LOCAL];
+		sin6[TCPDROP_LOCAL].sin6_family = AF_INET6;
+		sin6[TCPDROP_LOCAL].sin6_port = inc->inc_lport;
+		memcpy(&sin6[TCPDROP_LOCAL].sin6_addr, &inc->inc6_laddr,
+		    sizeof inc->inc6_laddr);
+		local = (struct sockaddr *)&sin6[TCPDROP_LOCAL];
+
+		sin6[TCPDROP_FOREIGN].sin6_len = sizeof sin6[TCPDROP_FOREIGN];
+		sin6[TCPDROP_FOREIGN].sin6_family = AF_INET6;
+		sin6[TCPDROP_FOREIGN].sin6_port = inc->inc_fport;
+		memcpy(&sin6[TCPDROP_FOREIGN].sin6_addr, &inc->inc6_faddr,
+		    sizeof inc->inc6_faddr);
+		foreign = (struct sockaddr *)&sin6[TCPDROP_FOREIGN];
+	} else {
+		memset(&sin4[TCPDROP_LOCAL], 0, sizeof sin4[TCPDROP_LOCAL]);
+
+		sin4[TCPDROP_LOCAL].sin_len = sizeof sin4[TCPDROP_LOCAL];
+		sin4[TCPDROP_LOCAL].sin_family = AF_INET;
+		sin4[TCPDROP_LOCAL].sin_port = inc->inc_lport;
+		memcpy(&sin4[TCPDROP_LOCAL].sin_addr, &inc->inc_laddr,
+		    sizeof inc->inc_laddr);
+		local = (struct sockaddr *)&sin4[TCPDROP_LOCAL];
+
+		sin4[TCPDROP_FOREIGN].sin_len = sizeof sin4[TCPDROP_FOREIGN];
+		sin4[TCPDROP_FOREIGN].sin_family = AF_INET;
+		sin4[TCPDROP_FOREIGN].sin_port = inc->inc_fport;
+		memcpy(&sin4[TCPDROP_FOREIGN].sin_addr, &inc->inc_faddr,
+		    sizeof inc->inc_faddr);
+		foreign = (struct sockaddr *)&sin4[TCPDROP_FOREIGN];
+	}
+
+	return (tcpdrop(local, foreign));
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr,
+"usage: tcpdrop local-address local-port foreign-address foreign-port\n"
+"       tcpdrop [-l] -a\n");
+	exit(1);
 }