5 files changed, 141 insertions, 63 deletions

diff --git a/share/man/man4/ddb.4 b/share/man/man4/ddb.4
index b24add039a46..f7704b25e43f 100644
--- a/share/man/man4/ddb.4
+++ b/share/man/man4/ddb.4
@@ -1192,7 +1192,7 @@ In remote GDB mode, another machine is required that runs
 using the remote debug feature, with a connection to the serial
 console port on the target machine.
 .Pp
-.It Ic netdump Fl s Ar server Oo Fl g Ar gateway Oc Fl c Ar client Fl i Ar iface
+.It Ic netdump Fl s Ar server Oo Fl g Ar gateway Fl c Ar client Fl i Ar iface Oc
 Configure
 .Xr netdump 4
 with the provided parameters, and immediately perform a netdump.
diff --git a/sys/net/debugnet.c b/sys/net/debugnet.c
index a82225a5af64..fabb89c7c1af 100644
--- a/sys/net/debugnet.c
+++ b/sys/net/debugnet.c
@@ -491,8 +491,12 @@ debugnet_free(struct debugnet_pcb *pcb)
 	MPASS(pcb == &g_dnet_pcb);
 
 	ifp = pcb->dp_ifp;
-	ifp->if_input = pcb->dp_drv_input;
-	ifp->if_debugnet_methods->dn_event(ifp, DEBUGNET_END);
+	if (ifp != NULL) {
+		if (pcb->dp_drv_input != NULL)
+			ifp->if_input = pcb->dp_drv_input;
+		if (pcb->dp_event_started)
+			ifp->if_debugnet_methods->dn_event(ifp, DEBUGNET_END);
+	}
 	debugnet_mbuf_finish();
 
 	g_debugnet_pcb_inuse = false;
@@ -527,8 +531,87 @@ debugnet_connect(const struct debugnet_conn_params *dcp,
 	/* Switch to the debugnet mbuf zones. */
 	debugnet_mbuf_start();
 
+	/* At least one needed parameter is missing; infer it. */
+	if (pcb->dp_client == INADDR_ANY || pcb->dp_gateway == INADDR_ANY ||
+	    pcb->dp_ifp == NULL) {
+		struct sockaddr_in dest_sin, *gw_sin, *local_sin;
+		struct rtentry *dest_rt;
+		struct ifnet *rt_ifp;
+
+		memset(&dest_sin, 0, sizeof(dest_sin));
+		dest_sin = (struct sockaddr_in) {
+			.sin_len = sizeof(dest_sin),
+			.sin_family = AF_INET,
+			.sin_addr.s_addr = pcb->dp_server,
+		};
+
+		CURVNET_SET(vnet0);
+		dest_rt = rtalloc1((struct sockaddr *)&dest_sin, 0,
+		    RTF_RNH_LOCKED);
+		CURVNET_RESTORE();
+
+		if (dest_rt == NULL) {
+			db_printf("%s: Could not get route for that server.\n",
+			    __func__);
+			error = ENOENT;
+			goto cleanup;
+		}
+
+		if (dest_rt->rt_gateway->sa_family == AF_INET)
+			gw_sin = (struct sockaddr_in *)dest_rt->rt_gateway;
+		else {
+			if (dest_rt->rt_gateway->sa_family == AF_LINK)
+				DNETDEBUG("Destination address is on link.\n");
+			gw_sin = NULL;
+		}
+
+		MPASS(dest_rt->rt_ifa->ifa_addr->sa_family == AF_INET);
+		local_sin = (struct sockaddr_in *)dest_rt->rt_ifa->ifa_addr;
+
+		rt_ifp = dest_rt->rt_ifp;
+
+		if (pcb->dp_client == INADDR_ANY)
+			pcb->dp_client = local_sin->sin_addr.s_addr;
+		if (pcb->dp_gateway == INADDR_ANY && gw_sin != NULL)
+			pcb->dp_gateway = gw_sin->sin_addr.s_addr;
+		if (pcb->dp_ifp == NULL)
+			pcb->dp_ifp = rt_ifp;
+
+		RTFREE_LOCKED(dest_rt);
+	}
+
 	ifp = pcb->dp_ifp;
+
+	if (debugnet_debug > 0) {
+		char serbuf[INET_ADDRSTRLEN], clibuf[INET_ADDRSTRLEN],
+		    gwbuf[INET_ADDRSTRLEN];
+		inet_ntop(AF_INET, &pcb->dp_server, serbuf, sizeof(serbuf));
+		inet_ntop(AF_INET, &pcb->dp_client, clibuf, sizeof(clibuf));
+		if (pcb->dp_gateway != INADDR_ANY)
+			inet_ntop(AF_INET, &pcb->dp_gateway, gwbuf, sizeof(gwbuf));
+		DNETDEBUG("Connecting to %s:%d%s%s from %s:%d on %s\n",
+		    serbuf, pcb->dp_server_port,
+		    (pcb->dp_gateway == INADDR_ANY) ? "" : " via ",
+		    (pcb->dp_gateway == INADDR_ANY) ? "" : gwbuf,
+		    clibuf, pcb->dp_client_ack_port, if_name(ifp));
+	}
+
+	/* Validate iface is online and supported. */
+	if (!DEBUGNET_SUPPORTED_NIC(ifp)) {
+		printf("%s: interface '%s' does not support debugnet\n",
+		    __func__, if_name(ifp));
+		error = ENODEV;
+		goto cleanup;
+	}
+	if ((if_getflags(ifp) & IFF_UP) == 0) {
+		printf("%s: interface '%s' link is down\n", __func__,
+		    if_name(ifp));
+		error = ENXIO;
+		goto cleanup;
+	}
+
 	ifp->if_debugnet_methods->dn_event(ifp, DEBUGNET_START);
+	pcb->dp_event_started = true;
 
 	/*
 	 * We maintain the invariant that g_debugnet_pcb_inuse is always true
@@ -842,37 +925,21 @@ debugnet_parse_ddb_cmd(const char *cmd, struct debugnet_ddb_config *result)
 		t = db_read_token_flags(DRT_WSPACE);
 	}
 
-	/* Currently, all three are required. */
-	if (!opt_client.has_opt || !opt_server.has_opt || ifp == NULL) {
-		db_printf("%s needs all of client, server, and interface "
-		    "specified.\n", cmd);
+	if (!opt_server.has_opt) {
+		db_printf("%s: need a destination server address\n", cmd);
 		goto usage;
 	}
 
+	result->dd_has_client = opt_client.has_opt;
 	result->dd_has_gateway = opt_gateway.has_opt;
-
-	/* Iface validation stolen from netdump_configure. */
-	if (!DEBUGNET_SUPPORTED_NIC(ifp)) {
-		db_printf("%s: interface '%s' does not support debugnet\n",
-		    cmd, if_name(ifp));
-		error = ENODEV;
-		goto cleanup;
-	}
-	if ((if_getflags(ifp) & IFF_UP) == 0) {
-		db_printf("%s: interface '%s' link is down\n", cmd,
-		    if_name(ifp));
-		error = ENXIO;
-		goto cleanup;
-	}
-
 	result->dd_ifp = ifp;
 
 	/* We parsed the full line to tEOL already, or bailed with an error. */
 	return (0);
 
 usage:
-	db_printf("Usage: %s -s <server> [-g <gateway>] -c <localip> "
-	    "-i <interface>\n", cmd);
+	db_printf("Usage: %s -s <server> [-g <gateway> -c <localip> "
+	    "-i <interface>]\n", cmd);
 	error = EINVAL;
 	/* FALLTHROUGH */
 cleanup:
diff --git a/sys/net/debugnet.h b/sys/net/debugnet.h
index 772bc1b62466..53a9052f5529 100644
--- a/sys/net/debugnet.h
+++ b/sys/net/debugnet.h
@@ -176,11 +176,12 @@ void debugnet_any_ifnet_update(struct ifnet *);
 /*
  * DDB parsing helper for common debugnet options.
  *
- * -s <server> [-g <gateway] -c <localip> -i <interface>
+ * -s <server> [-g <gateway -c <localip> -i <interface>]
  *
  * Order is not significant.  Interface is an online interface that supports
  * debugnet and can route to the debugnet server.  The other parameters are all
- * IP addresses.  For now, all parameters are mandatory, except gateway.
+ * IP addresses.  Only the server parameter is required.  The others are
+ * inferred automatically from the routing table, if not explicitly provided.
  *
  * Provides basic '-h' using provided 'cmd' string.
  *
@@ -191,6 +192,7 @@ struct debugnet_ddb_config {
 	in_addr_t	dd_client;
 	in_addr_t	dd_server;
 	in_addr_t	dd_gateway;
+	bool		dd_has_client : 1;
 	bool		dd_has_gateway : 1;
 };
 int debugnet_parse_ddb_cmd(const char *cmd,
diff --git a/sys/net/debugnet_int.h b/sys/net/debugnet_int.h
index 0dd206cf6761..4d204c973dff 100644
--- a/sys/net/debugnet_int.h
+++ b/sys/net/debugnet_int.h
@@ -69,6 +69,7 @@ struct debugnet_pcb {
 
 	enum dnet_pcb_st	dp_state;
 	uint16_t		dp_client_ack_port;
+	bool			dp_event_started;
 };
 
 /* TODO(CEM): Obviate this assertion by using a BITSET(9) for acks. */
diff --git a/sys/netinet/netdump/netdump_client.c b/sys/netinet/netdump/netdump_client.c
index ce44347611d0..6e9cd025a87e 100644
--- a/sys/netinet/netdump/netdump_client.c
+++ b/sys/netinet/netdump/netdump_client.c
@@ -138,8 +138,8 @@ static int nd_debug;
 SYSCTL_INT(_net_netdump, OID_AUTO, debug, CTLFLAG_RWTUN,
     &nd_debug, 0,
     "Debug message verbosity");
-SYSCTL_PROC(_net_netdump, OID_AUTO, enabled, CTLFLAG_RD | CTLTYPE_INT,
-    &nd_ifp, 0, netdump_enabled_sysctl, "I", "netdump configuration status");
+SYSCTL_PROC(_net_netdump, OID_AUTO, enabled, CTLFLAG_RD | CTLTYPE_INT, NULL, 0,
+    netdump_enabled_sysctl, "I", "netdump configuration status");
 static char nd_path[MAXPATHLEN];
 SYSCTL_STRING(_net_netdump, OID_AUTO, path, CTLFLAG_RW,
     nd_path, sizeof(nd_path),
@@ -158,12 +158,21 @@ SYSCTL_INT(_net_netdump, OID_AUTO, arp_retries, CTLFLAG_RWTUN,
     &debugnet_arp_nretries, 0,
     "Number of ARP attempts before giving up");
 
+static bool nd_is_enabled;
 static bool
 netdump_enabled(void)
 {
 
 	NETDUMP_ASSERT_LOCKED();
-	return (nd_ifp != NULL);
+	return (nd_is_enabled);
+}
+
+static void
+netdump_set_enabled(bool status)
+{
+
+	NETDUMP_ASSERT_LOCKED();
+	nd_is_enabled = status;
 }
 
 static int
@@ -296,10 +305,6 @@ netdump_start(struct dumperinfo *di)
 		printf("netdump_start: can't netdump; no server IP given\n");
 		return (EINVAL);
 	}
-	if (nd_client.s_addr == INADDR_ANY) {
-		printf("netdump_start: can't netdump; no client IP given\n");
-		return (EINVAL);
-	}
 
 	/* We start dumping at offset 0. */
 	di->dumpoff = 0;
@@ -369,14 +374,16 @@ netdump_unconfigure(void)
 	struct diocskerneldump_arg kda;
 
 	NETDUMP_ASSERT_WLOCKED();
-	KASSERT(netdump_enabled(), ("%s: nd_ifp NULL", __func__));
+	KASSERT(netdump_enabled(), ("%s: not enabled", __func__));
 
 	bzero(&kda, sizeof(kda));
 	kda.kda_index = KDA_REMOVE_DEV;
 	(void)dumper_remove(nd_conf.ndc_iface, &kda);
 
-	if_rele(nd_ifp);
+	if (nd_ifp != NULL)
+		if_rele(nd_ifp);
 	nd_ifp = NULL;
+	netdump_set_enabled(false);
 
 	log(LOG_WARNING, "netdump: Lost configured interface %s\n",
 	    nd_conf.ndc_iface);
@@ -406,32 +413,25 @@ netdump_configure(struct diocskerneldump_arg *conf, struct thread *td)
 
 	NETDUMP_ASSERT_WLOCKED();
 
-	if (td != NULL)
-		vnet = TD_TO_VNET(td);
-	else
-		vnet = vnet0;
-	CURVNET_SET(vnet);
-	if (td != NULL && !IS_DEFAULT_VNET(curvnet)) {
+	if (conf->kda_iface[0] != 0) {
+		if (td != NULL)
+			vnet = TD_TO_VNET(td);
+		else
+			vnet = vnet0;
+		CURVNET_SET(vnet);
+		if (td != NULL && !IS_DEFAULT_VNET(curvnet)) {
+			CURVNET_RESTORE();
+			return (EINVAL);
+		}
+		ifp = ifunit_ref(conf->kda_iface);
 		CURVNET_RESTORE();
-		return (EINVAL);
-	}
-	ifp = ifunit_ref(conf->kda_iface);
-	CURVNET_RESTORE();
-
-	if (ifp == NULL)
-		return (ENOENT);
-	if ((if_getflags(ifp) & IFF_UP) == 0) {
-		if_rele(ifp);
-		return (ENXIO);
-	}
-	if (!DEBUGNET_SUPPORTED_NIC(ifp)) {
-		if_rele(ifp);
-		return (ENODEV);
-	}
+	} else
+		ifp = NULL;
 
-	if (netdump_enabled())
+	if (nd_ifp != NULL)
 		if_rele(nd_ifp);
 	nd_ifp = ifp;
+	netdump_set_enabled(true);
 
 #define COPY_SIZED(elm) do {	\
 	_Static_assert(sizeof(nd_conf.ndc_ ## elm) ==			\
@@ -527,8 +527,9 @@ netdump_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr,
 			break;
 		}
 
-		strlcpy(conf12->ndc12_iface, nd_ifp->if_xname,
-		    sizeof(conf12->ndc12_iface));
+		if (nd_ifp != NULL)
+			strlcpy(conf12->ndc12_iface, nd_ifp->if_xname,
+			    sizeof(conf12->ndc12_iface));
 		memcpy(&conf12->ndc12_server, &nd_server,
 		    sizeof(conf12->ndc12_server));
 		memcpy(&conf12->ndc12_client, &nd_client,
@@ -549,8 +550,9 @@ netdump_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr,
 			break;
 		}
 
-		strlcpy(conf->kda_iface, nd_ifp->if_xname,
-		    sizeof(conf->kda_iface));
+		if (nd_ifp != NULL)
+			strlcpy(conf->kda_iface, nd_ifp->if_xname,
+			    sizeof(conf->kda_iface));
 		memcpy(&conf->kda_server, &nd_server, sizeof(nd_server));
 		memcpy(&conf->kda_client, &nd_client, sizeof(nd_client));
 		memcpy(&conf->kda_gateway, &nd_gateway, sizeof(nd_gateway));
@@ -776,11 +778,17 @@ DB_FUNC(netdump, db_netdump_cmd, db_cmd_table, CS_OWN, NULL)
 
 	/* Translate to a netdump dumper config. */
 	memset(&conf, 0, sizeof(conf));
-	strlcpy(conf.kda_iface, if_name(params.dd_ifp), sizeof(conf.kda_iface));
+
+	if (params.dd_ifp != NULL)
+		strlcpy(conf.kda_iface, if_name(params.dd_ifp),
+		    sizeof(conf.kda_iface));
 
 	conf.kda_af = AF_INET;
 	conf.kda_server.in4 = (struct in_addr) { params.dd_server };
-	conf.kda_client.in4 = (struct in_addr) { params.dd_client };
+	if (params.dd_has_client)
+		conf.kda_client.in4 = (struct in_addr) { params.dd_client };
+	else
+		conf.kda_client.in4 = (struct in_addr) { INADDR_ANY };
 	if (params.dd_has_gateway)
 		conf.kda_gateway.in4 = (struct in_addr) { params.dd_gateway };
 	else