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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
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
Diffstat (limited to 'sys')
-rw-r--r--sys/amd64/conf/GENERIC1
-rw-r--r--sys/conf/NOTES10
-rw-r--r--sys/conf/files1
-rw-r--r--sys/conf/options6
-rw-r--r--sys/gdb/gdb.h8
-rw-r--r--sys/gdb/gdb_int.h11
-rw-r--r--sys/gdb/gdb_main.c29
-rw-r--r--sys/gdb/gdb_packet.c54
-rw-r--r--sys/gdb/netgdb.c406
-rw-r--r--sys/gdb/netgdb.h44
-rw-r--r--sys/i386/conf/GENERIC1
-rw-r--r--sys/kern/subr_kdb.c1
-rw-r--r--sys/net/debugnet.c16
-rw-r--r--sys/net/debugnet.h22
-rw-r--r--sys/net/debugnet_inet.c2
-rw-r--r--sys/net/debugnet_int.h1
-rw-r--r--sys/sys/kdb.h3
-rw-r--r--sys/sys/param.h2
18 files changed, 600 insertions, 18 deletions
diff --git a/sys/amd64/conf/GENERIC b/sys/amd64/conf/GENERIC
index a3e75a7ac136..30246adb4857 100644
--- a/sys/amd64/conf/GENERIC
+++ b/sys/amd64/conf/GENERIC
@@ -113,6 +113,7 @@ options GZIO # gzip-compressed kernel and user dumps
options ZSTDIO # zstd-compressed kernel and user dumps
options DEBUGNET # debugnet networking
options NETDUMP # netdump(4) client support
+options NETGDB # netgdb(4) client support
# Make an SMP-capable kernel by default
options SMP # Symmetric MultiProcessor Kernel
diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 7892a2391bc8..002d809eae5d 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -1038,13 +1038,17 @@ options TCP_SIGNATURE #include support for RFC 2385
# a smooth scheduling of the traffic.
options DUMMYNET
+# The DEBUGNET option enables a basic debug/panic-time networking API. It
+# is used by NETDUMP and NETGDB.
+options DEBUGNET
+
# The NETDUMP option enables netdump(4) client support in the kernel.
# This allows a panicking kernel to transmit a kernel dump to a remote host.
options NETDUMP
-# The DEBUGNET option enables a basic debug/panic-time networking API. It
-# is used by NETDUMP.
-options DEBUGNET
+# The NETGDB option enables netgdb(4) support in the kernel. This allows a
+# panicking kernel to be debugged as a GDB remote over the network.
+options NETGDB
#####################################################################
# FILESYSTEM OPTIONS
diff --git a/sys/conf/files b/sys/conf/files
index d910a1f0ce17..e47fe27466cf 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -3546,6 +3546,7 @@ fs/tmpfs/tmpfs_subr.c optional tmpfs
gdb/gdb_cons.c optional gdb
gdb/gdb_main.c optional gdb
gdb/gdb_packet.c optional gdb
+gdb/netgdb.c optional ddb debugnet gdb netgdb inet
geom/bde/g_bde.c optional geom_bde
geom/bde/g_bde_crypt.c optional geom_bde
geom/bde/g_bde_lock.c optional geom_bde
diff --git a/sys/conf/options b/sys/conf/options
index d9ea0a821cb3..0600bf52203b 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -319,10 +319,12 @@ NFS_ROOT opt_nfsroot.h
# SMB/CIFS requester
NETSMB opt_netsmb.h
-# Enable netdump(4) client support.
-NETDUMP opt_global.h
# Enable debugnet(4) networking support.
DEBUGNET opt_global.h
+# Enable netdump(4) client support.
+NETDUMP opt_global.h
+# Enable netgdb(4) support.
+NETGDB opt_global.h
# Options used only in subr_param.c.
HZ opt_param.h
diff --git a/sys/gdb/gdb.h b/sys/gdb/gdb.h
index 0a7ba9c4b56a..3a570da7d75c 100644
--- a/sys/gdb/gdb.h
+++ b/sys/gdb/gdb.h
@@ -46,8 +46,16 @@ struct gdb_dbgport {
gdb_putc_f *gdb_putc;
gdb_term_f *gdb_term;
int gdb_active;
+ void (*gdb_sendpacket)(const void *, size_t);
+ int gdb_dbfeatures;
};
+#define GDB_DBGP_FEAT_WANTTERM 0x1 /* Want gdb_term() invocation when
+ leaving GDB. gdb_term has been
+ deadcode and never invoked for so
+ long I don't want to just blindly
+ start invoking it without opt-in. */
+
#define GDB_DBGPORT(name, probe, init, term, getc, putc) \
static struct gdb_dbgport name##_gdb_dbgport = { \
.gdb_name = #name, \
diff --git a/sys/gdb/gdb_int.h b/sys/gdb/gdb_int.h
index b4b28bd47b0b..2bea90ccf3e8 100644
--- a/sys/gdb/gdb_int.h
+++ b/sys/gdb/gdb_int.h
@@ -31,8 +31,14 @@
#ifndef _GDB_GDB_INT_H_
#define _GDB_GDB_INT_H_
+#include "opt_ddb.h"
+
#include <sys/sysctl.h>
+#ifdef DDB
+#include <ddb/ddb.h>
+#endif
+
#ifndef EOF
#define EOF (-1)
#endif
@@ -48,6 +54,11 @@ extern char *gdb_rxp;
extern size_t gdb_rxsz;
extern char *gdb_txp;
+#ifdef DDB
+/* If set, return to DDB when controlling GDB detaches. */
+extern bool gdb_return_to_ddb;
+#endif
+
int gdb_rx_begin(void);
int gdb_rx_equal(const char *);
int gdb_rx_mem(unsigned char *, size_t);
diff --git a/sys/gdb/gdb_main.c b/sys/gdb/gdb_main.c
index e9de5a332b0a..134a5a339513 100644
--- a/sys/gdb/gdb_main.c
+++ b/sys/gdb/gdb_main.c
@@ -60,6 +60,10 @@ int gdb_listening = 0;
static unsigned char gdb_bindata[64];
+#ifdef DDB
+bool gdb_return_to_ddb = false;
+#endif
+
static int
gdb_init(void)
{
@@ -569,6 +573,26 @@ unrecognized:
return;
}
+static void
+gdb_handle_detach(void)
+{
+ kdb_cpu_clear_singlestep();
+ gdb_listening = 0;
+
+ if (gdb_cur->gdb_dbfeatures & GDB_DBGP_FEAT_WANTTERM)
+ gdb_cur->gdb_term();
+
+#ifdef DDB
+ if (!gdb_return_to_ddb)
+ return;
+
+ gdb_return_to_ddb = false;
+
+ if (kdb_dbbe_select("ddb") != 0)
+ printf("The ddb backend could not be selected.\n");
+#endif
+}
+
static int
gdb_trap(int type, int code)
{
@@ -638,7 +662,7 @@ gdb_trap(int type, int code)
}
case 'D': { /* Detach */
gdb_tx_ok();
- kdb_cpu_clear_singlestep();
+ gdb_handle_detach();
return (1);
}
case 'g': { /* Read registers. */
@@ -675,8 +699,7 @@ gdb_trap(int type, int code)
break;
}
case 'k': /* Kill request. */
- kdb_cpu_clear_singlestep();
- gdb_listening = 1;
+ gdb_handle_detach();
return (1);
case 'm': { /* Read memory. */
uintmax_t addr, size;
diff --git a/sys/gdb/gdb_packet.c b/sys/gdb/gdb_packet.c
index 2a8f982ba49c..e740b2c9442e 100644
--- a/sys/gdb/gdb_packet.c
+++ b/sys/gdb/gdb_packet.c
@@ -45,7 +45,27 @@ __FBSDID("$FreeBSD$");
static char gdb_rxbuf[GDB_BUFSZ];
char *gdb_rxp = NULL;
size_t gdb_rxsz = 0;
-static char gdb_txbuf[GDB_BUFSZ];
+
+/*
+ * The goal here is to allow in-place framing without making the math around
+ * 'gdb_txbuf' more complicated. A generous reading of union special rule for
+ * "common initial sequence" suggests this may be valid in standard C99 and
+ * later.
+ */
+static union {
+ struct _midbuf {
+ char mb_pad1;
+ char mb_buf[GDB_BUFSZ];
+ char mb_pad2[4];
+ } __packed txu_midbuf;
+ /* sizeof includes trailing nul byte and this is intentional. */
+ char txu_fullbuf[GDB_BUFSZ + sizeof("$#..")];
+} gdb_tx_u;
+#define gdb_txbuf gdb_tx_u.txu_midbuf.mb_buf
+#define gdb_tx_fullbuf gdb_tx_u.txu_fullbuf
+_Static_assert(sizeof(gdb_tx_u.txu_midbuf) == sizeof(gdb_tx_u.txu_fullbuf) &&
+ offsetof(struct _midbuf, mb_buf) == 1,
+ "assertions necessary for correctness");
char *gdb_txp = NULL; /* Used in inline functions. */
#define C2N(c) (((c) < 'A') ? (c) - '0' : \
@@ -68,6 +88,9 @@ gdb_getc(void)
if (c == CTRL('C')) {
printf("Received ^C; trying to switch back to ddb.\n");
+ if (gdb_cur->gdb_dbfeatures & GDB_DBGP_FEAT_WANTTERM)
+ gdb_cur->gdb_term();
+
if (kdb_dbbe_select("ddb") != 0)
printf("The ddb backend could not be selected.\n");
else {
@@ -218,6 +241,29 @@ gdb_tx_begin(char tp)
gdb_tx_char(tp);
}
+/*
+ * Take raw packet buffer and perform typical GDB packet framing, but not run-
+ * length encoding, before forwarding to driver ::gdb_sendpacket() routine.
+ */
+static void
+gdb_tx_sendpacket(void)
+{
+ size_t msglen, i;
+ unsigned char csum;
+
+ msglen = gdb_txp - gdb_txbuf;
+
+ /* Add GDB packet framing */
+ gdb_tx_fullbuf[0] = '$';
+
+ csum = 0;
+ for (i = 0; i < msglen; i++)
+ csum += (unsigned char)gdb_txbuf[i];
+ snprintf(&gdb_tx_fullbuf[1 + msglen], 4, "#%02x", (unsigned)csum);
+
+ gdb_cur->gdb_sendpacket(gdb_tx_fullbuf, msglen + 4);
+}
+
int
gdb_tx_end(void)
{
@@ -226,6 +272,11 @@ gdb_tx_end(void)
unsigned char c, cksum;
do {
+ if (gdb_cur->gdb_sendpacket != NULL) {
+ gdb_tx_sendpacket();
+ goto getack;
+ }
+
gdb_cur->gdb_putc('$');
cksum = 0;
@@ -284,6 +335,7 @@ gdb_tx_end(void)
c = cksum & 0x0f;
gdb_cur->gdb_putc(N2C(c));
+getack:
c = gdb_getc();
} while (c != '+');
diff --git a/sys/gdb/netgdb.c b/sys/gdb/netgdb.c
new file mode 100644
index 000000000000..de069903c5de
--- /dev/null
+++ b/sys/gdb/netgdb.c
@@ -0,0 +1,406 @@
+/*-
+ * 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.
+ */
+
+/*
+ * netgdb.c
+ * FreeBSD subsystem supporting debugging the FreeBSD kernel over the network.
+ *
+ * There are three pieces necessary to use NetGDB.
+ *
+ * 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). 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>' to connect
+ * to the proxy server.
+ *
+ * NetGDBv1 speaks the literal GDB remote serial protocol, and uses a 1:1
+ * relationship between GDB packets and plain debugnet packets. There is no
+ * encryption utilized to keep debugging sessions private, so this is only
+ * appropriate for local segments or trusted networks.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_ddb.h"
+#ifndef DDB
+#error "NetGDB cannot be used without DDB at this time"
+#endif
+
+#include <sys/param.h>
+#include <sys/kdb.h>
+#include <sys/sbuf.h>
+#include <sys/socket.h>
+#include <sys/sysctl.h>
+#include <sys/ttydefaults.h>
+
+#include <machine/gdb_machdep.h>
+
+#ifdef DDB
+#include <ddb/ddb.h>
+#include <ddb/db_command.h>
+#include <ddb/db_lex.h>
+#endif
+
+#include <net/debugnet.h>
+#include <net/if.h>
+#include <net/if_var.h>
+#include <net/route.h>
+
+#include <gdb/gdb.h>
+#include <gdb/gdb_int.h>
+#include <gdb/netgdb.h>
+
+FEATURE(netgdb, "NetGDB support");
+SYSCTL_NODE(_debug_gdb, OID_AUTO, netgdb, CTLFLAG_RD, NULL,
+ "NetGDB parameters");
+
+static unsigned netgdb_debug;
+SYSCTL_UINT(_debug_gdb_netgdb, OID_AUTO, debug, CTLFLAG_RWTUN,
+ &netgdb_debug, 0,
+ "Debug message verbosity (0: off; 1: on)");
+
+#define NETGDB_DEBUG(f, ...) do { \
+ if (netgdb_debug > 0) \
+ printf(("%s [%s:%d]: " f), __func__, __FILE__, __LINE__, ## \
+ __VA_ARGS__); \
+} while (false)
+
+static void netgdb_fini(void);
+
+/* Runtime state. */
+static char netgdb_rxbuf[GDB_BUFSZ + 16]; /* Some overhead for framing. */
+static struct sbuf netgdb_rxsb;
+static ssize_t netgdb_rx_off;
+
+static struct debugnet_pcb *netgdb_conn;
+static struct gdb_dbgport *netgdb_prev_dbgport;
+static int *netgdb_prev_kdb_inactive;
+
+/* TODO(CEM) disable ack mode */
+
+/*
+ * Receive non-TX ACK packets on the client port.
+ *
+ * The mbuf chain will have all non-debugnet framing headers removed
+ * (ethernet, inet, udp). It will start with a debugnet_msg_hdr, of
+ * which the header is guaranteed to be contiguous. If m_pullup is
+ * used, the supplied in-out mbuf pointer should be updated
+ * appropriately.
+ *
+ * If the handler frees the mbuf chain, it should set the mbuf pointer
+ * to NULL. Otherwise, the debugnet input framework will free the
+ * chain.
+ */
+static void
+netgdb_rx(struct debugnet_pcb *pcb, struct mbuf **mb)
+{
+ const struct debugnet_msg_hdr *dnh;
+ struct mbuf *m;
+ uint32_t rlen, count;
+ int error;
+
+ m = *mb;
+ dnh = mtod(m, const void *);
+
+ if (ntohl(dnh->mh_type) == DEBUGNET_FINISHED) {
+ sbuf_putc(&netgdb_rxsb, CTRL('C'));
+ return;
+ }
+
+ if (ntohl(dnh->mh_type) != DEBUGNET_DATA) {
+ printf("%s: Got unexpected debugnet message %u\n",
+ __func__, ntohl(dnh->mh_type));
+ return;
+ }
+
+ rlen = ntohl(dnh->mh_len);
+#define _SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
+ if (_SBUF_FREESPACE(&netgdb_rxsb) < rlen) {
+ NETGDB_DEBUG("Backpressure: Not ACKing RX of packet that "
+ "would overflow our buffer (%zd/%zd used).\n",
+ netgdb_rxsb.s_len, netgdb_rxsb.s_size);
+ return;
+ }
+#undef _SBUF_FREESPACE
+
+ error = debugnet_ack_output(pcb, dnh->mh_seqno);
+ if (error != 0) {
+ printf("%s: Couldn't ACK rx packet %u; %d\n", __func__,
+ ntohl(dnh->mh_seqno), error);
+ /*
+ * Sender will re-xmit, and assuming the condition is
+ * transient, we'll process the packet's contentss later.
+ */
+ return;
+ }
+
+ m_adj(m, sizeof(*dnh));
+ dnh = NULL;
+
+ /*
+ * Inlined m_apply -- why isn't there a macro or inline function
+ * version?
+ */
+ while (m != NULL && m->m_len == 0)
+ m = m->m_next;
+ while (rlen > 0) {
+ MPASS(m != NULL && m->m_len >= 0);
+ count = min((uint32_t)m->m_len, rlen);
+ (void)sbuf_bcat(&netgdb_rxsb, mtod(m, const void *), count);
+ rlen -= count;
+ m = m->m_next;
+ }
+}
+
+/*
+ * The following routines implement a pseudo GDB debugport (an emulated serial
+ * driver that the MI gdb(4) code does I/O with).
+ */
+
+static int
+netgdb_dbg_getc(void)
+{
+ int c;
+
+ while (true) {
+ /* Pull bytes off any currently cached packet first. */
+ if (netgdb_rx_off < sbuf_len(&netgdb_rxsb)) {
+ c = netgdb_rxsb.s_buf[netgdb_rx_off];
+ netgdb_rx_off++;
+ break;
+ }
+
+ /* Reached EOF? Reuse buffer. */
+ sbuf_clear(&netgdb_rxsb);
+ netgdb_rx_off = 0;
+
+ /* Check for CTRL-C on console/serial, if any. */
+ if (netgdb_prev_dbgport != NULL) {
+ c = netgdb_prev_dbgport->gdb_getc();
+ if (c == CTRL('C'))
+ break;
+ }
+
+ debugnet_network_poll(netgdb_conn);
+ }
+
+ if (c == CTRL('C')) {
+ netgdb_fini();
+ /* Caller gdb_getc() will print that we got ^C. */
+ }
+ return (c);
+}
+
+static void
+netgdb_dbg_sendpacket(const void *buf, size_t len)
+{
+ struct debugnet_proto_aux aux;
+ int error;
+
+ MPASS(len <= UINT32_MAX);
+
+ /*
+ * GDB packet boundaries matter. debugnet_send() fragments a single
+ * request into many sequential debugnet messages. Mark full packet
+ * length and offset for potential reassembly by the proxy.
+ */
+ aux = (struct debugnet_proto_aux) {
+ .dp_aux2 = len,
+ };
+
+ error = debugnet_send(netgdb_conn, DEBUGNET_DATA, buf, len, &aux);
+ if (error != 0) {
+ printf("%s: Network error: %d; trying to switch back to ddb.\n",
+ __func__, error);
+ netgdb_fini();
+
+ if (kdb_dbbe_select("ddb") != 0)
+ printf("The ddb backend could not be selected.\n");
+ else {
+ printf("using longjmp, hope it works!\n");
+ kdb_reenter();
+ }
+ }
+
+}
+
+/* Just used for + / - GDB-level ACKs. */
+static void
+netgdb_dbg_putc(int i)
+{
+ char c;
+
+ c = i;
+ netgdb_dbg_sendpacket(&c, 1);
+
+}
+
+static struct gdb_dbgport netgdb_gdb_dbgport = {
+ .gdb_name = "netgdb",
+ .gdb_getc = netgdb_dbg_getc,
+ .gdb_putc = netgdb_dbg_putc,
+ .gdb_term = netgdb_fini,
+ .gdb_sendpacket = netgdb_dbg_sendpacket,
+ .gdb_dbfeatures = GDB_DBGP_FEAT_WANTTERM,
+};
+
+static void
+netgdb_init(void)
+{
+ struct kdb_dbbe *be, **iter;
+
+ /*
+ * Force enable GDB. (If no other debugports were registered at boot,
+ * KDB thinks it doesn't exist.)
+ */
+ SET_FOREACH(iter, kdb_dbbe_set) {
+ be = *iter;
+ if (strcmp(be->dbbe_name, "gdb") != 0)
+ continue;
+ if (be->dbbe_active == -1) {
+ netgdb_prev_kdb_inactive = &be->dbbe_active;
+ be->dbbe_active = 0;
+ }
+ break;
+ }
+
+ /* Force netgdb debugport. */
+ netgdb_prev_dbgport = gdb_cur;
+ gdb_cur = &netgdb_gdb_dbgport;
+
+ sbuf_new(&netgdb_rxsb, netgdb_rxbuf, sizeof(netgdb_rxbuf),
+ SBUF_FIXEDLEN);
+ netgdb_rx_off = 0;
+}
+
+static void
+netgdb_fini(void)
+{
+
+ /* TODO: tear down conn gracefully? */
+ if (netgdb_conn != NULL) {
+ debugnet_free(netgdb_conn);
+ netgdb_conn = NULL;
+ }
+
+ sbuf_delete(&netgdb_rxsb);
+
+ gdb_cur = netgdb_prev_dbgport;
+
+ if (netgdb_prev_kdb_inactive != NULL) {
+ *netgdb_prev_kdb_inactive = -1;
+ netgdb_prev_kdb_inactive = NULL;
+ }
+}
+
+#ifdef DDB
+/*
+ * Usage: netgdb -s <server> [-g <gateway -c <localip> -i <interface>]
+ *
+ * Order is not significant.
+ *
+ * Currently, this command does not support configuring encryption or
+ * compression.
+ */
+DB_FUNC(netgdb, db_netgdb_cmd, db_cmd_table, CS_OWN, NULL)
+{
+ struct debugnet_ddb_config params;
+ struct debugnet_conn_params dcp;
+ struct debugnet_pcb *pcb;
+ int error;
+
+ if (panicstr == NULL) {
+ /* TODO: This limitation should be removed in future work. */
+ printf("%s: netgdb is currently limited to use only after a "
+ "panic. Sorry.\n", __func__);
+ return;
+ }
+
+ error = debugnet_parse_ddb_cmd("netgdb", &params);
+ if (error != 0) {
+ db_printf("Error configuring netgdb: %d\n", error);
+ return;
+ }
+
+ /*
+ * Must initialize netgdb_rxsb before debugnet_connect(), because we
+ * might be getting rx handler callbacks from the send->poll path
+ * during debugnet_connect().
+ */
+ netgdb_init();
+
+ if (!params.dd_has_client)
+ params.dd_client = INADDR_ANY;
+ if (!params.dd_has_gateway)
+ params.dd_gateway = INADDR_ANY;
+
+ dcp = (struct debugnet_conn_params) {
+ .dc_ifp = params.dd_ifp,
+ .dc_client = params.dd_client,
+ .dc_server = params.dd_server,
+ .dc_gateway = params.dd_gateway,
+ .dc_herald_port = NETGDB_HERALDPORT,
+ .dc_client_port = NETGDB_CLIENTPORT,
+ .dc_herald_aux2 = NETGDB_PROTO_V1,
+ .dc_rx_handler = netgdb_rx,
+ };
+
+ error = debugnet_connect(&dcp, &pcb);
+ if (error != 0) {
+ printf("failed to contact netgdb server: %d\n", error);
+ netgdb_fini();
+ return;
+ }
+
+ netgdb_conn = pcb;
+
+ if (kdb_dbbe_select("gdb") != 0) {
+ db_printf("The remote GDB backend could not be selected.\n");
+ netgdb_fini();
+ return;
+ }
+
+ /*
+ * Mark that we are done in ddb(4). Return -> kdb_trap() should
+ * re-enter with the new backend.
+ */
+ db_cmd_loop_done = 1;
+ gdb_return_to_ddb = true;
+ db_printf("(detaching GDB will return control to DDB)\n");
+#if 0
+ /* Aspirational, but does not work reliably. */
+ db_printf("(ctrl-c will return control to ddb)\n");
+#endif
+}
+#endif /* DDB */
diff --git a/sys/gdb/netgdb.h b/sys/gdb/netgdb.h
new file mode 100644
index 000000000000..36f369312290
--- /dev/null
+++ b/sys/gdb/netgdb.h
@@ -0,0 +1,44 @@
+/*-
+ * 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. */
diff --git a/sys/i386/conf/GENERIC b/sys/i386/conf/GENERIC
index 4d29e889defd..0aef50a08ea0 100644
--- a/sys/i386/conf/GENERIC
+++ b/sys/i386/conf/GENERIC
@@ -101,6 +101,7 @@ options GZIO # gzip-compressed kernel and user dumps
options ZSTDIO # zstd-compressed kernel and user dumps
options DEBUGNET # debugnet networking
options NETDUMP # netdump(4) client support
+options NETGDB # netgdb(4) client support
# To make an SMP kernel, the next two lines are needed
options SMP # Symmetric MultiProcessor Kernel
diff --git a/sys/kern/subr_kdb.c b/sys/kern/subr_kdb.c
index f6f105743245..07a2c7da5a7e 100644
--- a/sys/kern/subr_kdb.c
+++ b/sys/kern/subr_kdb.c
@@ -77,7 +77,6 @@ static int kdb_break_to_debugger = KDB_BREAK_TO_DEBUGGER;
static int kdb_alt_break_to_debugger = KDB_ALT_BREAK_TO_DEBUGGER;
KDB_BACKEND(null, NULL, NULL, NULL, NULL);
-SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe);
static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS);
static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
diff --git a/sys/net/debugnet.c b/sys/net/debugnet.c
index c42812709e9c..160fd1ebaeca 100644
--- a/sys/net/debugnet.c
+++ b/sys/net/debugnet.c
@@ -183,7 +183,7 @@ debugnet_udp_output(struct debugnet_pcb *pcb, struct mbuf *m)
return (debugnet_ip_output(pcb, m));
}
-static int
+int
debugnet_ack_output(struct debugnet_pcb *pcb, uint32_t seqno /* net endian */)
{
struct debugnet_ack *dn_ack;
@@ -330,7 +330,7 @@ retransmit:
printf(". ");
goto retransmit;
}
- debugnet_network_poll(pcb->dp_ifp);
+ debugnet_network_poll(pcb);
DELAY(500);
if (pcb->dp_state == DN_STATE_REMOTE_CLOSED)
return (ECONNRESET);
@@ -577,8 +577,11 @@ done:
* driver directly for packets.
*/
void
-debugnet_network_poll(struct ifnet *ifp)
+debugnet_network_poll(struct debugnet_pcb *pcb)
{
+ struct ifnet *ifp;
+
+ ifp = pcb->dp_ifp;
ifp->if_debugnet_methods->dn_poll(ifp, 1000);
}
@@ -610,6 +613,7 @@ int
debugnet_connect(const struct debugnet_conn_params *dcp,
struct debugnet_pcb **pcb_out)
{
+ struct debugnet_proto_aux herald_auxdata;
struct debugnet_pcb *pcb;
struct ifnet *ifp;
int error;
@@ -738,8 +742,12 @@ debugnet_connect(const struct debugnet_conn_params *dcp,
}
MPASS(pcb->dp_state == DN_STATE_HAVE_GW_MAC);
+ herald_auxdata = (struct debugnet_proto_aux) {
+ .dp_offset_start = dcp->dc_herald_offset,
+ .dp_aux2 = dcp->dc_herald_aux2,
+ };
error = debugnet_send(pcb, DEBUGNET_HERALD, dcp->dc_herald_data,
- dcp->dc_herald_datalen, NULL);
+ dcp->dc_herald_datalen, &herald_auxdata);
if (error != 0) {
printf("%s: failed to herald debugnet server\n", __func__);
goto cleanup;
diff --git a/sys/net/debugnet.h b/sys/net/debugnet.h
index 87fc9ba0a07c..7b323ad113d7 100644
--- a/sys/net/debugnet.h
+++ b/sys/net/debugnet.h
@@ -108,6 +108,14 @@ struct debugnet_conn_params {
uint32_t dc_herald_datalen;
/*
+ * Consistent with debugnet_send(), aux paramaters to debugnet
+ * functions are provided host-endian (but converted to
+ * network endian on the wire).
+ */
+ uint32_t dc_herald_aux2;
+ uint64_t dc_herald_offset;
+
+ /*
* If NULL, debugnet is a unidirectional channel from panic machine to
* remote server (like netdump).
*
@@ -123,12 +131,14 @@ struct debugnet_conn_params {
* If the handler frees the mbuf chain, it should set the mbuf pointer
* to NULL. Otherwise, the debugnet input framework will free the
* chain.
+ *
+ * The handler should ACK receieved packets with debugnet_ack_output.
*/
void (*dc_rx_handler)(struct debugnet_pcb *, struct mbuf **);
};
/*
- * Open a unidirectional stream to the specified server's herald port.
+ * Open a stream to the specified server's herald port.
*
* If all goes well, the server will send ACK from a different port to our ack
* port. This allows servers to somewhat gracefully handle multiple debugnet
@@ -178,6 +188,16 @@ debugnet_sendempty(struct debugnet_pcb *pcb, uint32_t mhtype)
}
/*
+ * Full-duplex RX should ACK received messages.
+ */
+int debugnet_ack_output(struct debugnet_pcb *, uint32_t seqno /*net endian*/);
+
+/*
+ * Check and/or wait for further packets.
+ */
+void debugnet_network_poll(struct debugnet_pcb *);
+
+/*
* PCB accessors.
*/
diff --git a/sys/net/debugnet_inet.c b/sys/net/debugnet_inet.c
index e57b4810653f..983c5add533f 100644
--- a/sys/net/debugnet_inet.c
+++ b/sys/net/debugnet_inet.c
@@ -407,7 +407,7 @@ restart:
return (error);
for (polls = 0; polls < debugnet_npolls &&
pcb->dp_state < DN_STATE_HAVE_GW_MAC; polls++) {
- debugnet_network_poll(pcb->dp_ifp);
+ debugnet_network_poll(pcb);
DELAY(500);
}
if (pcb->dp_state >= DN_STATE_HAVE_GW_MAC)
diff --git a/sys/net/debugnet_int.h b/sys/net/debugnet_int.h
index 1e723c4d93f9..00a4e0c25c75 100644
--- a/sys/net/debugnet_int.h
+++ b/sys/net/debugnet_int.h
@@ -87,7 +87,6 @@ SYSCTL_DECL(_net_debugnet);
int debugnet_ether_output(struct mbuf *, struct ifnet *, struct ether_addr,
u_short);
void debugnet_handle_udp(struct debugnet_pcb *, struct mbuf **);
-void debugnet_network_poll(struct ifnet *);
#ifdef INET
int debugnet_arp_gw(struct debugnet_pcb *);
diff --git a/sys/sys/kdb.h b/sys/sys/kdb.h
index 75f8343b8428..a70e88627718 100644
--- a/sys/sys/kdb.h
+++ b/sys/sys/kdb.h
@@ -31,6 +31,7 @@
#ifndef _SYS_KDB_H_
#define _SYS_KDB_H_
+#include <sys/linker_set.h>
#include <machine/setjmp.h>
struct pcb;
@@ -61,6 +62,8 @@ struct kdb_dbbe {
}; \
DATA_SET(kdb_dbbe_set, name##_dbbe)
+SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe);
+
extern u_char kdb_active; /* Non-zero while in debugger. */
extern int debugger_on_trap; /* enter the debugger on trap. */
extern struct kdb_dbbe *kdb_dbbe; /* Default debugger backend or NULL. */
diff --git a/sys/sys/param.h b/sys/sys/param.h
index 561015c0568b..2c1f8b46305d 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -60,7 +60,7 @@
* in the range 5 to 9.
*/
#undef __FreeBSD_version
-#define __FreeBSD_version 1300052 /* Master, propagated to newvers */
+#define __FreeBSD_version 1300053 /* Master, propagated to newvers */
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,