netdump_client.c

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/*-
 * Copyright (c) 2005-2014 Sandvine Incorporated. All rights reserved.
 * Copyright (c) 2000 Darrell Anderson
 * All rights reserved.
 *
 * 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.
 */
 
/*
 * netdump_client.c
 * FreeBSD subsystem supporting netdump network dumps.
 * A dedicated server must be running to accept client dumps.
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include "opt_ddb.h"
 
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/disk.h>
#include <sys/endian.h>
#include <sys/eventhandler.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/kerneldump.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
 
#ifdef DDB
#include <ddb/ddb.h>
#include <ddb/db_lex.h>
#endif
 
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/debugnet.h>
 
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/netdump/netdump.h>
 
#include <machine/in_cksum.h>
#include <machine/pcb.h>
 
#define NETDDEBUGV(f, ...) do {                                         \
        if (nd_debug > 1)                                               \
                printf(("%s: " f), __func__, ## __VA_ARGS__);           \
} while (0)
 
static void      netdump_cleanup(void);
static int       netdump_configure(struct diocskerneldump_arg *,
                    struct thread *);
static int       netdump_dumper(void *priv __unused, void *virtual,
                    vm_offset_t physical __unused, off_t offset, size_t length);
static bool      netdump_enabled(void);
static int       netdump_enabled_sysctl(SYSCTL_HANDLER_ARGS);
static int       netdump_ioctl(struct cdev *dev __unused, u_long cmd,
                    caddr_t addr, int flags __unused, struct thread *td);
static int       netdump_modevent(module_t mod, int type, void *priv);
static int       netdump_start(struct dumperinfo *di, void *key,
                    uint32_t keysize);
static void      netdump_unconfigure(void);
 
/* Must be at least as big as the chunks dumpsys() gives us. */
static unsigned char nd_buf[MAXDUMPPGS * PAGE_SIZE];
static int dump_failed;
 
/* Configuration parameters. */
static struct {
        char             ndc_iface[IFNAMSIZ];
        union kd_ip      ndc_server;
        union kd_ip      ndc_client;
        union kd_ip      ndc_gateway;
        uint8_t          ndc_af;
        /* Runtime State */
        struct debugnet_pcb *nd_pcb;
        off_t            nd_tx_off;
        size_t           nd_buf_len;
} nd_conf;
#define nd_server       nd_conf.ndc_server.in4
#define nd_client       nd_conf.ndc_client.in4
#define nd_gateway      nd_conf.ndc_gateway.in4
 
/* General dynamic settings. */
static struct sx nd_conf_lk;
SX_SYSINIT(nd_conf, &nd_conf_lk, "netdump configuration lock");
#define NETDUMP_WLOCK()                 sx_xlock(&nd_conf_lk)
#define NETDUMP_WUNLOCK()               sx_xunlock(&nd_conf_lk)
#define NETDUMP_RLOCK()                 sx_slock(&nd_conf_lk)
#define NETDUMP_RUNLOCK()               sx_sunlock(&nd_conf_lk)
#define NETDUMP_ASSERT_WLOCKED()        sx_assert(&nd_conf_lk, SA_XLOCKED)
#define NETDUMP_ASSERT_LOCKED()         sx_assert(&nd_conf_lk, SA_LOCKED)
static struct ifnet *nd_ifp;
static eventhandler_tag nd_detach_cookie;
 
FEATURE(netdump, "Netdump client support");
 
static SYSCTL_NODE(_net, OID_AUTO, netdump, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
    "netdump parameters");
 
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 | CTLFLAG_MPSAFE, 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),
    "Server path for output files");
/*
 * The following three variables were moved to debugnet(4), but these knobs
 * were retained as aliases.
 */
SYSCTL_INT(_net_netdump, OID_AUTO, polls, CTLFLAG_RWTUN,
    &debugnet_npolls, 0,
    "Number of times to poll before assuming packet loss (0.5ms per poll)");
SYSCTL_INT(_net_netdump, OID_AUTO, retries, CTLFLAG_RWTUN,
    &debugnet_nretries, 0,
    "Number of retransmit attempts before giving up");
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_is_enabled);
}
 
static void
netdump_set_enabled(bool status)
{
 
        NETDUMP_ASSERT_LOCKED();
        nd_is_enabled = status;
}
 
static int
netdump_enabled_sysctl(SYSCTL_HANDLER_ARGS)
{
        int en, error;
 
        NETDUMP_RLOCK();
        en = netdump_enabled();
        NETDUMP_RUNLOCK();
 
        error = SYSCTL_OUT(req, &en, sizeof(en));
        if (error != 0 || req->newptr == NULL)
                return (error);
        return (EPERM);
}
 
/*-
 * Dumping specific primitives.
 */
 
/*
 * Flush any buffered vmcore data.
 */
static int
netdump_flush_buf(void)
{
        int error;
 
        error = 0;
        if (nd_conf.nd_buf_len != 0) {
                struct debugnet_proto_aux auxdata = {
                        .dp_offset_start = nd_conf.nd_tx_off,
                };
                error = debugnet_send(nd_conf.nd_pcb, DEBUGNET_DATA, nd_buf,
                    nd_conf.nd_buf_len, &auxdata);
                if (error == 0)
                        nd_conf.nd_buf_len = 0;
        }
        return (error);
}
 
/*
 * Callback from dumpsys() to dump a chunk of memory.
 * Copies it out to our static buffer then sends it across the network.
 * Detects the initial KDH and makes sure it is given a special packet type.
 *
 * Parameters:
 *      priv     Unused. Optional private pointer.
 *      virtual  Virtual address (where to read the data from)
 *      physical Unused. Physical memory address.
 *      offset   Offset from start of core file
 *      length   Data length
 *
 * Return value:
 *      0 on success
 *      errno on error
 */
static int
netdump_dumper(void *priv __unused, void *virtual,
    vm_offset_t physical __unused, off_t offset, size_t length)
{
        int error;
 
        NETDDEBUGV("netdump_dumper(NULL, %p, NULL, %ju, %zu)\n",
            virtual, (uintmax_t)offset, length);
 
        if (virtual == NULL) {
                error = netdump_flush_buf();
                if (error != 0)
                        dump_failed = 1;
 
                if (dump_failed != 0)
                        printf("failed to dump the kernel core\n");
                else if (
                    debugnet_sendempty(nd_conf.nd_pcb, DEBUGNET_FINISHED) != 0)
                        printf("failed to close the transaction\n");
                else
                        printf("\nnetdump finished.\n");
                netdump_cleanup();
                return (0);
        }
        if (length > sizeof(nd_buf)) {
                netdump_cleanup();
                return (ENOSPC);
        }
 
        if (nd_conf.nd_buf_len + length > sizeof(nd_buf) ||
            (nd_conf.nd_buf_len != 0 && nd_conf.nd_tx_off +
            nd_conf.nd_buf_len != offset)) {
                error = netdump_flush_buf();
                if (error != 0) {
                        dump_failed = 1;
                        netdump_cleanup();
                        return (error);
                }
                nd_conf.nd_tx_off = offset;
        }
 
        memmove(nd_buf + nd_conf.nd_buf_len, virtual, length);
        nd_conf.nd_buf_len += length;
 
        return (0);
}
 
/*
 * Perform any initialization needed prior to transmitting the kernel core.
 */
static int
netdump_start(struct dumperinfo *di, void *key, uint32_t keysize)
{
        struct debugnet_conn_params dcp;
        struct debugnet_pcb *pcb;
        char buf[INET_ADDRSTRLEN];
        int error;
 
        error = 0;
 
        /* Check if the dumping is allowed to continue. */
        if (!netdump_enabled())
                return (EINVAL);
 
        if (!KERNEL_PANICKED()) {
                printf(
                    "netdump_start: netdump may only be used after a panic\n");
                return (EINVAL);
        }
 
        memset(&dcp, 0, sizeof(dcp));
 
        if (nd_server.s_addr == INADDR_ANY) {
                printf("netdump_start: can't netdump; no server IP given\n");
                return (EINVAL);
        }
 
        /* We start dumping at offset 0. */
        di->dumpoff = 0;
 
        dcp.dc_ifp = nd_ifp;
 
        dcp.dc_client = nd_client.s_addr;
        dcp.dc_server = nd_server.s_addr;
        dcp.dc_gateway = nd_gateway.s_addr;
 
        dcp.dc_herald_port = NETDUMP_PORT;
        dcp.dc_client_port = NETDUMP_ACKPORT;
 
        dcp.dc_herald_data = nd_path;
        dcp.dc_herald_datalen = (nd_path[0] == 0) ? 0 : strlen(nd_path) + 1;
 
        error = debugnet_connect(&dcp, &pcb);
        if (error != 0) {
                printf("failed to contact netdump server\n");
                /* Squash debugnet to something the dumper code understands. */
                return (EINVAL);
        }
 
        printf("netdumping to %s (%6D)\n", inet_ntoa_r(nd_server, buf),
            debugnet_get_gw_mac(pcb), ":");
        nd_conf.nd_pcb = pcb;
 
        /* Send the key before the dump so a partial dump is still usable. */
        if (keysize > 0) {
                if (keysize > sizeof(nd_buf)) {
                        printf("crypto key is too large (%u)\n", keysize);
                        error = EINVAL;
                        goto out;
                }
                memcpy(nd_buf, key, keysize);
                error = debugnet_send(pcb, NETDUMP_EKCD_KEY, nd_buf, keysize,
                    NULL);
                if (error != 0) {
                        printf("error %d sending crypto key\n", error);
                        goto out;
                }
        }
 
out:
        if (error != 0) {
                /* As above, squash errors. */
                error = EINVAL;
                netdump_cleanup();
        }
        return (error);
}
 
static int
netdump_write_headers(struct dumperinfo *di, struct kerneldumpheader *kdh)
{
        int error;
 
        error = netdump_flush_buf();
        if (error != 0)
                goto out;
        memcpy(nd_buf, kdh, sizeof(*kdh));
        error = debugnet_send(nd_conf.nd_pcb, NETDUMP_KDH, nd_buf,
            sizeof(*kdh), NULL);
out:
        if (error != 0)
                netdump_cleanup();
        return (error);
}
 
/*
 * Cleanup routine for a possibly failed netdump.
 */
static void
netdump_cleanup(void)
{
        if (nd_conf.nd_pcb != NULL) {
                debugnet_free(nd_conf.nd_pcb);
                nd_conf.nd_pcb = NULL;
        }
}
 
/*-
 * KLD specific code.
 */
 
static struct cdevsw netdump_cdevsw = {
        .d_version =    D_VERSION,
        .d_ioctl =      netdump_ioctl,
        .d_name =       "netdump",
};
 
static struct cdev *netdump_cdev;
 
static void
netdump_unconfigure(void)
{
        struct diocskerneldump_arg kda;
 
        NETDUMP_ASSERT_WLOCKED();
        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 (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);
 
        bzero(&nd_conf, sizeof(nd_conf));
}
 
static void
netdump_ifdetach(void *arg __unused, struct ifnet *ifp)
{
 
        NETDUMP_WLOCK();
        if (ifp == nd_ifp)
                netdump_unconfigure();
        NETDUMP_WUNLOCK();
}
 
/*
 * td of NULL is a sentinel value that indicates a kernel caller (ddb(4) or
 * modload-based tunable parameters).
 */
static int
netdump_configure(struct diocskerneldump_arg *conf, struct thread *td)
{
        struct ifnet *ifp;
 
        NETDUMP_ASSERT_WLOCKED();
 
        if (conf->kda_iface[0] != 0) {
                if (td != NULL && !IS_DEFAULT_VNET(TD_TO_VNET(td)))
                        return (EINVAL);
                CURVNET_SET(vnet0);
                ifp = ifunit_ref(conf->kda_iface);
                CURVNET_RESTORE();
        } else
                ifp = NULL;
 
        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) ==                   \
            sizeof(conf->kda_ ## elm), "elm " __XSTRING(elm) " mismatch"); \
        memcpy(&nd_conf.ndc_ ## elm, &conf->kda_ ## elm,                \
            sizeof(nd_conf.ndc_ ## elm));                               \
} while (0)
        COPY_SIZED(iface);
        COPY_SIZED(server);
        COPY_SIZED(client);
        COPY_SIZED(gateway);
        COPY_SIZED(af);
#undef COPY_SIZED
 
        return (0);
}
 
/*
 * ioctl(2) handler for the netdump device. This is currently only used to
 * register netdump as a dump device.
 *
 * Parameters:
 *     dev, Unused.
 *     cmd, The ioctl to be handled.
 *     addr, The parameter for the ioctl.
 *     flags, Unused.
 *     td, The thread invoking this ioctl.
 *
 * Returns:
 *     0 on success, and an errno value on failure.
 */
static int
netdump_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr,
    int flags __unused, struct thread *td)
{
        struct diocskerneldump_arg kda_copy, *conf;
        struct dumperinfo dumper;
        uint8_t *encryptedkey;
        int error;
#ifdef COMPAT_FREEBSD11
        u_int u;
#endif
#ifdef COMPAT_FREEBSD12
        struct diocskerneldump_arg_freebsd12 *kda12;
        struct netdump_conf_freebsd12 *conf12;
#endif
 
        conf = NULL;
        error = 0;
        NETDUMP_WLOCK();
 
        switch (cmd) {
#ifdef COMPAT_FREEBSD11
        case DIOCSKERNELDUMP_FREEBSD11:
                gone_in(13, "11.x ABI compatibility");
                u = *(u_int *)addr;
                if (u != 0) {
                        error = ENXIO;
                        break;
                }
                if (netdump_enabled())
                        netdump_unconfigure();
                break;
#endif
#ifdef COMPAT_FREEBSD12
                /*
                 * Used by dumpon(8) in 12.x for clearing previous
                 * configuration -- then NETDUMPSCONF_FREEBSD12 is used to
                 * actually configure netdump.
                 */
        case DIOCSKERNELDUMP_FREEBSD12:
                gone_in(14, "12.x ABI compatibility");
 
                kda12 = (void *)addr;
                if (kda12->kda12_enable) {
                        error = ENXIO;
                        break;
                }
                if (netdump_enabled())
                        netdump_unconfigure();
                break;
 
        case NETDUMPGCONF_FREEBSD12:
                gone_in(14, "FreeBSD 12.x ABI compat");
                conf12 = (void *)addr;
 
                if (!netdump_enabled()) {
                        error = ENXIO;
                        break;
                }
                if (nd_conf.ndc_af != AF_INET) {
                        error = EOPNOTSUPP;
                        break;
                }
 
                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,
                    sizeof(conf12->ndc12_client));
                memcpy(&conf12->ndc12_gateway, &nd_gateway,
                    sizeof(conf12->ndc12_gateway));
                break;
#endif
        case DIOCGKERNELDUMP:
                conf = (void *)addr;
                /*
                 * For now, index is ignored; netdump doesn't support multiple
                 * configurations (yet).
                 */
                if (!netdump_enabled()) {
                        error = ENXIO;
                        conf = NULL;
                        break;
                }
 
                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));
                conf->kda_af = nd_conf.ndc_af;
                conf = NULL;
                break;
 
#ifdef COMPAT_FREEBSD12
        case NETDUMPSCONF_FREEBSD12:
                gone_in(14, "FreeBSD 12.x ABI compat");
 
                conf12 = (struct netdump_conf_freebsd12 *)addr;
 
                _Static_assert(offsetof(struct diocskerneldump_arg, kda_server)
                    == offsetof(struct netdump_conf_freebsd12, ndc12_server),
                    "simplifying assumption");
 
                memset(&kda_copy, 0, sizeof(kda_copy));
                memcpy(&kda_copy, conf12,
                    offsetof(struct diocskerneldump_arg, kda_server));
 
                /* 12.x ABI could only configure IPv4 (INET) netdump. */
                kda_copy.kda_af = AF_INET;
                memcpy(&kda_copy.kda_server.in4, &conf12->ndc12_server,
                    sizeof(struct in_addr));
                memcpy(&kda_copy.kda_client.in4, &conf12->ndc12_client,
                    sizeof(struct in_addr));
                memcpy(&kda_copy.kda_gateway.in4, &conf12->ndc12_gateway,
                    sizeof(struct in_addr));
 
                kda_copy.kda_index =
                    (conf12->ndc12_kda.kda12_enable ? 0 : KDA_REMOVE_ALL);
 
                conf = &kda_copy;
                explicit_bzero(conf12, sizeof(*conf12));
                /* FALLTHROUGH */
#endif
        case DIOCSKERNELDUMP:
                encryptedkey = NULL;
                if (cmd == DIOCSKERNELDUMP) {
                        conf = (void *)addr;
                        memcpy(&kda_copy, conf, sizeof(kda_copy));
                }
                /* Netdump only supports IP4 at this time. */
                if (conf->kda_af != AF_INET) {
                        error = EPROTONOSUPPORT;
                        break;
                }
 
                conf->kda_iface[sizeof(conf->kda_iface) - 1] = '\0';
                if (conf->kda_index == KDA_REMOVE ||
                    conf->kda_index == KDA_REMOVE_DEV ||
                    conf->kda_index == KDA_REMOVE_ALL) {
                        if (netdump_enabled())
                                netdump_unconfigure();
                        if (conf->kda_index == KDA_REMOVE_ALL)
                                error = dumper_remove(NULL, conf);
                        break;
                }
 
                error = netdump_configure(conf, td);
                if (error != 0)
                        break;
 
                if (conf->kda_encryption != KERNELDUMP_ENC_NONE) {
                        if (conf->kda_encryptedkeysize <= 0 ||
                            conf->kda_encryptedkeysize >
                            KERNELDUMP_ENCKEY_MAX_SIZE) {
                                error = EINVAL;
                                break;
                        }
                        encryptedkey = malloc(conf->kda_encryptedkeysize,
                            M_TEMP, M_WAITOK);
                        error = copyin(conf->kda_encryptedkey, encryptedkey,
                            conf->kda_encryptedkeysize);
                        if (error != 0) {
                                free(encryptedkey, M_TEMP);
                                break;
                        }
 
                        conf->kda_encryptedkey = encryptedkey;
                }
 
                memset(&dumper, 0, sizeof(dumper));
                dumper.dumper_start = netdump_start;
                dumper.dumper_hdr = netdump_write_headers;
                dumper.dumper = netdump_dumper;
                dumper.priv = NULL;
                dumper.blocksize = NETDUMP_DATASIZE;
                dumper.maxiosize = MAXDUMPPGS * PAGE_SIZE;
                dumper.mediaoffset = 0;
                dumper.mediasize = 0;
 
                error = dumper_insert(&dumper, conf->kda_iface, conf);
                zfree(encryptedkey, M_TEMP);
                if (error != 0)
                        netdump_unconfigure();
                break;
        default:
                error = ENOTTY;
                break;
        }
        explicit_bzero(&kda_copy, sizeof(kda_copy));
        if (conf != NULL)
                explicit_bzero(conf, sizeof(*conf));
        NETDUMP_WUNLOCK();
        return (error);
}
 
/*
 * Called upon system init or kld load.  Initializes the netdump parameters to
 * sane defaults (locates the first available NIC and uses the first IPv4 IP on
 * that card as the client IP).  Leaves the server IP unconfigured.
 *
 * Parameters:
 *      mod, Unused.
 *      what, The module event type.
 *      priv, Unused.
 *
 * Returns:
 *      int, An errno value if an error occured, 0 otherwise.
 */
static int
netdump_modevent(module_t mod __unused, int what, void *priv __unused)
{
        struct diocskerneldump_arg conf;
        char *arg;
        int error;
 
        error = 0;
        switch (what) {
        case MOD_LOAD:
                error = make_dev_p(MAKEDEV_WAITOK, &netdump_cdev,
                    &netdump_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "netdump");
                if (error != 0)
                        return (error);
 
                nd_detach_cookie = EVENTHANDLER_REGISTER(ifnet_departure_event,
                    netdump_ifdetach, NULL, EVENTHANDLER_PRI_ANY);
 
                if ((arg = kern_getenv("net.dump.iface")) != NULL) {
                        strlcpy(conf.kda_iface, arg, sizeof(conf.kda_iface));
                        freeenv(arg);
 
                        if ((arg = kern_getenv("net.dump.server")) != NULL) {
                                inet_aton(arg, &conf.kda_server.in4);
                                freeenv(arg);
                        }
                        if ((arg = kern_getenv("net.dump.client")) != NULL) {
                                inet_aton(arg, &conf.kda_client.in4);
                                freeenv(arg);
                        }
                        if ((arg = kern_getenv("net.dump.gateway")) != NULL) {
                                inet_aton(arg, &conf.kda_gateway.in4);
                                freeenv(arg);
                        }
                        conf.kda_af = AF_INET;
 
                        /* Ignore errors; we print a message to the console. */
                        NETDUMP_WLOCK();
                        (void)netdump_configure(&conf, NULL);
                        NETDUMP_WUNLOCK();
                }
                break;
        case MOD_UNLOAD:
                NETDUMP_WLOCK();
                if (netdump_enabled()) {
                        printf("netdump: disabling dump device for unload\n");
                        netdump_unconfigure();
                }
                NETDUMP_WUNLOCK();
                destroy_dev(netdump_cdev);
                EVENTHANDLER_DEREGISTER(ifnet_departure_event,
                    nd_detach_cookie);
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return (error);
}
 
static moduledata_t netdump_mod = {
        "netdump",
        netdump_modevent,
        NULL,
};
 
MODULE_VERSION(netdump, 1);
DECLARE_MODULE(netdump, netdump_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
 
#ifdef DDB
/*
 * Usage: netdump -s <server> [-g <gateway] -c <localip> -i <interface>
 *
 * Order is not significant.
 *
 * Currently, this command does not support configuring encryption or
 * compression.
 */
DB_FUNC(netdump, db_netdump_cmd, db_cmd_table, CS_OWN, NULL)
{
        static struct diocskerneldump_arg conf;
        static char blockbuf[NETDUMP_DATASIZE];
        static union {
                struct dumperinfo di;
                /* For valid di_devname. */
                char di_buf[sizeof(struct dumperinfo) + 1];
        } u;
 
        struct debugnet_ddb_config params;
        int error;
 
        error = debugnet_parse_ddb_cmd("netdump", &params);
        if (error != 0) {
                db_printf("Error configuring netdump: %d\n", error);
                return;
        }
 
        /* Translate to a netdump dumper config. */
        memset(&conf, 0, sizeof(conf));
 
        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 };
        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
                conf.kda_gateway.in4 = (struct in_addr) { INADDR_ANY };
 
        /* Set the global netdump config to these options. */
        error = netdump_configure(&conf, NULL);
        if (error != 0) {
                db_printf("Error enabling netdump: %d\n", error);
                return;
        }
 
        /* Fake the generic dump configuration list entry to avoid malloc. */
        memset(&u.di_buf, 0, sizeof(u.di_buf));
        u.di.dumper_start = netdump_start;
        u.di.dumper_hdr = netdump_write_headers;
        u.di.dumper = netdump_dumper;
        u.di.priv = NULL;
        u.di.blocksize = NETDUMP_DATASIZE;
        u.di.maxiosize = MAXDUMPPGS * PAGE_SIZE;
        u.di.mediaoffset = 0;
        u.di.mediasize = 0;
        u.di.blockbuf = blockbuf;
 
        dumper_ddb_insert(&u.di);
 
        error = doadump(false);
 
        dumper_ddb_remove(&u.di);
        if (error != 0)
                db_printf("Cannot dump: %d\n", error);
}
#endif /* DDB */