xref: /freebsd/sys/net/debugnet.h (revision fde2cf65)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2019 Isilon Systems, LLC.
5  * Copyright (c) 2005-2014 Sandvine Incorporated
6  * Copyright (c) 2000 Darrell Anderson <anderson@cs.duke.edu>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $FreeBSD$
31  */
32 
33 /*
34  * Debugnet provides a reliable, bidirectional, UDP-encapsulated datagram
35  * transport while a machine is in a debug state.  (N-1 CPUs stopped,
36  * interrupts disabled, may or may not be in a panic(9) state.)  Only one
37  * stream may be active at a time.  A dedicated server must be running to
38  * accept connections.
39  */
40 
41 #pragma once
42 
43 #include <sys/types.h>
44 #include <netinet/in.h>
45 
46 /*
47  * Debugnet protocol details.
48  */
49 #define	DEBUGNET_HERALD		1	/* Connection handshake. */
50 #define	DEBUGNET_FINISHED	2	/* Close the connection. */
51 #define	DEBUGNET_DATA		3	/* Contains data. */
52 
53 struct debugnet_msg_hdr {
54 	uint32_t	mh_type;	/* Debugnet message type. */
55 	uint32_t	mh_seqno;	/* Match acks with msgs. */
56 	uint64_t	mh_offset;	/* Offset in fragment. */
57 	uint32_t	mh_len;		/* Attached data (bytes). */
58 	uint32_t	mh_aux2;	/* Consumer-specific. */
59 } __packed;
60 
61 struct debugnet_ack {
62 	uint32_t	da_seqno;	/* Match acks with msgs. */
63 } __packed;
64 
65 #define	DEBUGNET_MAX_IN_FLIGHT	64
66 
67 #ifdef _KERNEL
68 /*
69  * Hook API for network drivers.
70  */
71 enum debugnet_ev {
72 	DEBUGNET_START,
73 	DEBUGNET_END,
74 };
75 
76 struct ifnet;
77 struct mbuf;
78 typedef void debugnet_init_t(struct ifnet *, int *nrxr, int *ncl, int *clsize);
79 typedef void debugnet_event_t(struct ifnet *, enum debugnet_ev);
80 typedef int debugnet_transmit_t(struct ifnet *, struct mbuf *);
81 typedef int debugnet_poll_t(struct ifnet *, int);
82 
83 struct debugnet_methods {
84 	debugnet_init_t		*dn_init;
85 	debugnet_event_t	*dn_event;
86 	debugnet_transmit_t	*dn_transmit;
87 	debugnet_poll_t		*dn_poll;
88 };
89 
90 #define	DEBUGNET_SUPPORTED_NIC(ifp)				\
91 	((ifp)->if_debugnet_methods != NULL && (ifp)->if_type == IFT_ETHER)
92 
93 /*
94  * Debugnet consumer API.
95  */
96 struct debugnet_conn_params {
97 	struct ifnet	*dc_ifp;
98 	in_addr_t	dc_client;
99 	in_addr_t	dc_server;
100 	in_addr_t	dc_gateway;
101 
102 	uint16_t	dc_herald_port;
103 	uint16_t	dc_client_ack_port;
104 
105 	const void	*dc_herald_data;
106 	uint32_t	dc_herald_datalen;
107 };
108 
109 struct debugnet_pcb; /* opaque */
110 
111 /*
112  * Open a unidirectional stream to the specified server's herald port.
113  *
114  * If all goes well, the server will send ACK from a different port to our ack
115  * port.  This allows servers to somewhat gracefully handle multiple debugnet
116  * clients.  (Clients are limited to single connections.)
117  *
118  * Returns zero on success, or errno.
119  */
120 int debugnet_connect(const struct debugnet_conn_params *,
121     struct debugnet_pcb **pcb_out);
122 
123 /*
124  * Free a debugnet stream that was previously successfully opened.
125  *
126  * No attempt is made to cleanly terminate communication with the remote
127  * server.  Consumers should first send an empty DEBUGNET_FINISHED message, or
128  * otherwise let the remote know they are signing off.
129  */
130 void debugnet_free(struct debugnet_pcb *);
131 
132 /*
133  * Send a message, with common debugnet_msg_hdr header, to the connected remote
134  * server.
135  *
136  * - mhtype translates directly to mh_type (e.g., DEBUGNET_DATA, or some other
137  *   protocol-specific type).
138  * - Data and datalen describe the attached data; datalen may be zero.
139  * - If auxdata is NULL, mh_offset's initial value and mh_aux2 will be zero.
140  *   Otherwise, mh_offset's initial value will be auxdata->dp_offset_start and
141  *   mh_aux2 will have the value of auxdata->dp_aux2.
142  *
143  * Returns zero on success, or an errno on failure.
144  */
145 struct debugnet_proto_aux {
146 	uint64_t dp_offset_start;
147 	uint32_t dp_aux2;
148 };
149 int debugnet_send(struct debugnet_pcb *, uint32_t mhtype, const void *data,
150     uint32_t datalen, const struct debugnet_proto_aux *auxdata);
151 
152 /*
153  * A simple wrapper around the above when no data or auxdata is needed.
154  */
155 static inline int
156 debugnet_sendempty(struct debugnet_pcb *pcb, uint32_t mhtype)
157 {
158 	return (debugnet_send(pcb, mhtype, NULL, 0, NULL));
159 }
160 
161 /*
162  * PCB accessors.
163  */
164 
165 /*
166  * Get the 48-bit MAC address of the discovered next hop (gateway, or
167  * destination server if it is on the same segment.
168  */
169 const unsigned char *debugnet_get_gw_mac(const struct debugnet_pcb *);
170 
171 /*
172  * Callbacks from core mbuf code.
173  */
174 void debugnet_any_ifnet_update(struct ifnet *);
175 
176 /*
177  * DDB parsing helper for common debugnet options.
178  *
179  * -s <server> [-g <gateway -c <localip> -i <interface>]
180  *
181  * Order is not significant.  Interface is an online interface that supports
182  * debugnet and can route to the debugnet server.  The other parameters are all
183  * IP addresses.  Only the server parameter is required.  The others are
184  * inferred automatically from the routing table, if not explicitly provided.
185  *
186  * Provides basic '-h' using provided 'cmd' string.
187  *
188  * Returns zero on success, or errno.
189  */
190 struct debugnet_ddb_config {
191 	struct ifnet	*dd_ifp;	/* not ref'd */
192 	in_addr_t	dd_client;
193 	in_addr_t	dd_server;
194 	in_addr_t	dd_gateway;
195 	bool		dd_has_client : 1;
196 	bool		dd_has_gateway : 1;
197 };
198 int debugnet_parse_ddb_cmd(const char *cmd,
199     struct debugnet_ddb_config *result);
200 
201 /* Expose sysctl variables for netdump(4) to alias. */
202 extern int debugnet_npolls;
203 extern int debugnet_nretries;
204 extern int debugnet_arp_nretries;
205 
206 /*
207  * Conditionally-defined macros for device drivers so we can avoid ifdef
208  * wrappers in every single implementation.
209  */
210 #ifdef DEBUGNET
211 #define	DEBUGNET_DEFINE(driver)					\
212 	static debugnet_init_t driver##_debugnet_init;		\
213 	static debugnet_event_t driver##_debugnet_event;	\
214 	static debugnet_transmit_t driver##_debugnet_transmit;	\
215 	static debugnet_poll_t driver##_debugnet_poll;		\
216 								\
217 	static struct debugnet_methods driver##_debugnet_methods = { \
218 		.dn_init = driver##_debugnet_init,		\
219 		.dn_event = driver##_debugnet_event,		\
220 		.dn_transmit = driver##_debugnet_transmit,	\
221 		.dn_poll = driver##_debugnet_poll,		\
222 	}
223 
224 #define	DEBUGNET_NOTIFY_MTU(ifp)	debugnet_any_ifnet_update(ifp)
225 
226 #define	DEBUGNET_SET(ifp, driver)				\
227 	(ifp)->if_debugnet_methods = &driver##_debugnet_methods
228 
229 #else /* !DEBUGNET || !INET */
230 
231 #define	DEBUGNET_DEFINE(driver)
232 #define	DEBUGNET_NOTIFY_MTU(ifp)
233 #define	DEBUGNET_SET(ifp, driver)
234 
235 #endif /* DEBUGNET && INET */
236 #endif /* _KERNEL */
237