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authorConrad Meyer <cem@FreeBSD.org>2019-10-17 21:33:01 +0000
committerConrad Meyer <cem@FreeBSD.org>2019-10-17 21:33:01 +0000
commitdda17b3672f2c7f661699a69ea4462710a52480d (patch)
treefbc063b744e51a6513553568dd2481e81ebcf50b /sys/gdb/netgdb.h
parent092bacb2c4277cb9aae662f82ceeb4fabfdd818a (diff)
downloadsrc-dda17b3672f2c7f661699a69ea4462710a52480d.tar.gz
src-dda17b3672f2c7f661699a69ea4462710a52480d.zip
Implement NetGDB(4)
NetGDB(4) is a component of a system using a panic-time network stack to remotely debug crashed FreeBSD kernels over the network, instead of traditional serial interfaces. There are three pieces in the complete NetGDB system. First, a dedicated proxy server must be running to accept connections from both NetGDB and gdb(1), and pass bidirectional traffic between the two protocols. Second, the NetGDB client is activated much like ordinary 'gdb' and similarly to 'netdump' in ddb(4) after a panic. Like other debugnet(4) clients (netdump(4)), the network interface on the route to the proxy server must be online and support debugnet(4). Finally, the remote (k)gdb(1) uses 'target remote <proxy>:<port>' (like any other TCP remote) to connect to the proxy server. The NetGDB v1 protocol speaks the literal GDB remote serial protocol, and uses a 1:1 relationship between GDB packets and sequences of debugnet packets (fragmented by MTU). There is no encryption utilized to keep debugging sessions private, so this is only appropriate for local segments or trusted networks. Submitted by: John Reimer <john.reimer AT emc.com> (earlier version) Discussed some with: emaste, markj Relnotes: sure Differential Revision: https://reviews.freebsd.org/D21568
Notes
Notes: svn path=/head/; revision=353700
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+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2019 Isilon Systems, LLC.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+#pragma once
+
+/*
+ * Protocol information, for use by the userspace proxy server.
+ *
+ * It might make sense to allow not hardcoding these parameters as future work
+ * (e.g., for use in environments with arbitrary port filtering).
+ *
+ * The herald port is only used for initial handshake. The proxy server will
+ * choose a different remote port to connect back to the NetGDB client on by
+ * sending the HERALD ACK from that other port.
+ */
+#define NETGDB_HERALDPORT 20025
+#define NETGDB_CLIENTPORT 20026
+
+#define NETGDB_PROTO_V1 0x2515f095 /* Rolled a 2^32 sided die. */