/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2021 Tintri by DDN, Inc. All rights reserved.
 */

/*
 * The ipmgmtd daemon is started by ip-interface-management SMF service. This
 * daemon is used to manage, mapping of 'address object' to 'interface name' and
 * 'logical interface number', on which the address is created. It also provides
 * a means to update the ipadm persistent data-store.
 *
 * The daemon tracks the <addrobj, lifname> mapping in-memory using a linked
 * list `aobjmap'. Access to this list is synchronized using a readers-writers
 * lock. The active <addrobj, lifname> mapping is kept in
 * /etc/svc/volatile/ipadm/aobjmap.conf cache file, so that the mapping can be
 * recovered when ipmgmtd exits for some reason (e.g., when ipmgmtd is restarted
 * using svcadm or accidentally killed).
 *
 * Today, the persistent configuration of interfaces, addresses and protocol
 * properties is kept in /etc/ipadm/ipadm.conf. The access to the persistent
 * data store is synchronized using reader-writers lock `ipmgmt_dbconf_lock'.
 *
 * The communication between the library, libipadm.so and the daemon, is through
 * doors RPC. The library interacts with the daemon using the commands defined
 * by `ipmgmt_door_cmd_type_t'. Further any 'write' operation would require
 * the `NETWORK_INTERFACE_CONFIG_AUTH' authorization.
 *
 * On reboot, the aforementioned SMF service starts the daemon before any other
 * networking service that configures network IP interfaces is started.
 * Afterwards, the network/physical SMF script instantiates the persisted
 * network interfaces, interface properties and addresses.
 */

#include <errno.h>
#include <fcntl.h>
#include <priv_utils.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <unistd.h>
#include "ipmgmt_impl.h"
#include <zone.h>
#include <libipadm.h>
#include <libdladm.h>
#include <libdllink.h>
#include <net/route.h>
#include <ipadm_ipmgmt.h>
#include <sys/brand.h>

const char              *progname;

/* readers-writers lock for reading/writing daemon data store */
pthread_rwlock_t        ipmgmt_dbconf_lock = PTHREAD_RWLOCK_INITIALIZER;

/* tracks address object to {ifname|logical number|interface id} mapping */
ipmgmt_aobjmap_list_t   aobjmap;

/* used to communicate failure to parent process, which spawned the daemon */
static int              pfds[2];

/* file descriptor to IPMGMT_DOOR */
static int              ipmgmt_door_fd = -1;

static void             ipmgmt_exit(int);
static int              ipmgmt_init();
static int              ipmgmt_init_privileges();
static void             ipmgmt_ngz_persist_if();

static ipadm_handle_t iph;
typedef struct ipmgmt_pif_s {
        struct ipmgmt_pif_s     *pif_next;
        char                    pif_ifname[LIFNAMSIZ];
        boolean_t               pif_v4;
        boolean_t               pif_v6;
} ipmgmt_pif_t;

static ipmgmt_pif_t *ngz_pifs;

static int
ipmgmt_db_init()
{
        int             fd, err, scferr;
        scf_resources_t res;
        boolean_t       upgrade = B_TRUE;

        /*
         * Check to see if we need to upgrade the data-store. We need to
         * upgrade, if the version of the data-store does not match with
         * IPADM_DB_VERSION. Further, if we cannot determine the current
         * version of the data-store, we always err on the side of caution
         * and upgrade the data-store to current version.
         */
        if ((scferr = ipmgmt_create_scf_resources(IPMGMTD_FMRI, &res)) == 0)
                upgrade = ipmgmt_needs_upgrade(&res);
        if (upgrade) {
                err = ipmgmt_db_walk(ipmgmt_db_upgrade, NULL, IPADM_DB_WRITE);
                if (err != 0) {
                        ipmgmt_log(LOG_ERR, "could not upgrade the "
                            "ipadm data-store: %s", strerror(err));
                        err = 0;
                } else {
                        /*
                         * upgrade was success, let's update SCF with the
                         * current data-store version number.
                         */
                        if (scferr == 0)
                                ipmgmt_update_dbver(&res);
                }
        }
        if (scferr == 0)
                ipmgmt_release_scf_resources(&res);

        /* creates the address object data store, if it doesn't exist */
        if ((fd = open(ADDROBJ_MAPPING_DB_FILE, O_CREAT|O_RDONLY,
            IPADM_FILE_MODE)) == -1) {
                err = errno;
                ipmgmt_log(LOG_ERR, "could not open %s: %s",
                    ADDROBJ_MAPPING_DB_FILE, strerror(err));
                return (err);
        }
        (void) close(fd);

        aobjmap.aobjmap_head = NULL;
        (void) pthread_rwlock_init(&aobjmap.aobjmap_rwlock, NULL);

        /*
         * If the daemon is recovering from a crash or restart, read the
         * address object to logical interface mapping and build an in-memory
         * representation of the mapping. That is, build `aobjmap' structure
         * from address object data store.
         */
        if ((err = ipadm_rw_db(ipmgmt_aobjmap_init, NULL,
            ADDROBJ_MAPPING_DB_FILE, 0, IPADM_DB_READ)) != 0) {
                /* if there was nothing to initialize, it's fine */
                if (err != ENOENT)
                        return (err);
                err = 0;
        }

        ipmgmt_ngz_persist_if(); /* create persistent interface info for NGZ */

        return (err);
}

static int
ipmgmt_door_init()
{
        int fd;
        int err;

        /* create the door file for ipmgmtd */
        if ((fd = open(IPMGMT_DOOR, O_CREAT|O_RDONLY, IPADM_FILE_MODE)) == -1) {
                err = errno;
                ipmgmt_log(LOG_ERR, "could not open %s: %s",
                    IPMGMT_DOOR, strerror(err));
                return (err);
        }
        (void) close(fd);

        if ((ipmgmt_door_fd = door_create(ipmgmt_handler, NULL,
            DOOR_REFUSE_DESC | DOOR_NO_CANCEL)) == -1) {
                err = errno;
                ipmgmt_log(LOG_ERR, "failed to create door: %s", strerror(err));
                return (err);
        }
        /*
         * fdetach first in case a previous daemon instance exited
         * ungracefully.
         */
        (void) fdetach(IPMGMT_DOOR);
        if (fattach(ipmgmt_door_fd, IPMGMT_DOOR) != 0) {
                err = errno;
                ipmgmt_log(LOG_ERR, "failed to attach door to %s: %s",
                    IPMGMT_DOOR, strerror(err));
                goto fail;
        }
        return (0);
fail:
        (void) door_revoke(ipmgmt_door_fd);
        ipmgmt_door_fd = -1;
        return (err);
}

static void
ipmgmt_door_fini()
{
        if (ipmgmt_door_fd == -1)
                return;

        (void) fdetach(IPMGMT_DOOR);
        if (door_revoke(ipmgmt_door_fd) == -1) {
                ipmgmt_log(LOG_ERR, "failed to revoke access to door %s: %s",
                    IPMGMT_DOOR, strerror(errno));
        }
}

static int
ipmgmt_init()
{
        int err;

        if (signal(SIGTERM, ipmgmt_exit) == SIG_ERR ||
            signal(SIGINT, ipmgmt_exit) == SIG_ERR) {
                err = errno;
                ipmgmt_log(LOG_ERR, "signal() for SIGTERM/INT failed: %s",
                    strerror(err));
                return (err);
        }
        if ((err = ipmgmt_db_init()) != 0 || (err = ipmgmt_door_init()) != 0)
                return (err);
        return (0);
}

/*
 * This is called by the child process to inform the parent process to
 * exit with the given return value.
 */
static void
ipmgmt_inform_parent_exit(int rv)
{
        if (write(pfds[1], &rv, sizeof (int)) != sizeof (int)) {
                ipmgmt_log(LOG_WARNING,
                    "failed to inform parent process of status: %s",
                    strerror(errno));
                (void) close(pfds[1]);
                exit(EXIT_FAILURE);
        }
        (void) close(pfds[1]);
}

/*ARGSUSED*/
static void
ipmgmt_exit(int signo)
{
        (void) close(pfds[1]);
        ipmgmt_door_fini();
        exit(EXIT_FAILURE);
}

/*
 * On the first reboot after installation of an ipkg zone,
 * ipmgmt_persist_if_cb() is used in non-global zones to track the interfaces
 * that have IP address configuration assignments from the global zone.
 * Persistent configuration for the interfaces is created on the first boot
 * by ipmgmtd, and the addresses assigned to the interfaces by the GZ
 * will be subsequently configured when the interface is enabled.
 * Note that ipmgmt_persist_if_cb() only sets up a list of interfaces
 * that need to be persisted- the actual update of the ipadm data-store happens
 * in ipmgmt_persist_if() after the appropriate privs/uid state has been set up.
 */
static void
ipmgmt_persist_if_cb(char *ifname, boolean_t v4, boolean_t v6)
{
        ipmgmt_pif_t *pif;

        pif = calloc(1, sizeof (*pif));
        if (pif == NULL) {
                ipmgmt_log(LOG_WARNING,
                    "Could not allocate memory to configure %s", ifname);
                return;
        }
        (void) strlcpy(pif->pif_ifname, ifname, sizeof (pif->pif_ifname));
        pif->pif_v4 = v4;
        pif->pif_v6 = v6;
        pif->pif_next = ngz_pifs;
        ngz_pifs = pif;
}

/*
 * ipmgmt_ngz_init() initializes exclusive-IP stack non-global zones by
 * extracting configuration that has been saved in the kernel and applying
 * it at zone boot.
 */
static void
ipmgmt_ngz_init()
{
        zoneid_t zoneid;
        boolean_t firstboot = B_TRUE, s10c = B_FALSE;
        char brand[MAXNAMELEN];
        ipadm_status_t ipstatus;

        zoneid = getzoneid();
        if (zoneid != GLOBAL_ZONEID) {

                if (zone_getattr(zoneid, ZONE_ATTR_BRAND, brand,
                    sizeof (brand)) < 0) {
                        ipmgmt_log(LOG_ERR, "Could not get brand name");
                        return;
                }
                /*
                 * firstboot is always true for S10C zones, where ipadm is not
                 * available for restoring persistent configuration.
                 */
                if (strcmp(brand, NATIVE_BRAND_NAME) == 0)
                        firstboot = ipmgmt_ngz_firstboot_postinstall();
                else
                        s10c = B_TRUE;

                if (!firstboot)
                        return;

                ipstatus = ipadm_open(&iph, IPH_IPMGMTD);
                if (ipstatus != IPADM_SUCCESS) {
                        ipmgmt_log(LOG_ERR, "could not open ipadm handle",
                            ipadm_status2str(ipstatus));
                        return;
                }
                /*
                 * Only pass down the callback to persist the interface
                 * for NATIVE (ipkg) zones.
                 */
                (void) ipadm_init_net_from_gz(iph, NULL,
                    (s10c ? NULL : ipmgmt_persist_if_cb));
                ipadm_close(iph);
        }
}

/*
 * Set the uid of this daemon to the "netadm" user. Finish the following
 * operations before setuid() because they need root privileges:
 *
 *    - create the /etc/svc/volatile/ipadm directory;
 *    - change its uid/gid to "netadm"/"netadm";
 */
static int
ipmgmt_init_privileges()
{
        struct stat     statbuf;
        int             err;

        /* create the IPADM_TMPFS_DIR directory */
        if (stat(IPADM_TMPFS_DIR, &statbuf) < 0) {
                if (mkdir(IPADM_TMPFS_DIR, (mode_t)0755) < 0) {
                        err = errno;
                        goto fail;
                }
        } else {
                if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
                        err = ENOTDIR;
                        goto fail;
                }
        }

        if ((chmod(IPADM_TMPFS_DIR, 0755) < 0) ||
            (chown(IPADM_TMPFS_DIR, UID_NETADM, GID_NETADM) < 0)) {
                err = errno;
                goto fail;
        }

        /*
         * initialize any NGZ specific network information before dropping
         * privileges. We need these privileges to plumb IP interfaces handed
         * down from the GZ (for dlpi_open() etc.) and also to configure the
         * address itself (for any IPI_PRIV ioctls like SLIFADDR)
         */
        ipmgmt_ngz_init();

        /*
         * Apply all protocol module properties. We need to apply all protocol
         * properties before we drop root privileges.
         */
        ipmgmt_init_prop();

        /*
         * limit the privileges of this daemon and set the uid of this
         * daemon to UID_NETADM
         */
        if (__init_daemon_priv(PU_RESETGROUPS|PU_CLEARLIMITSET, UID_NETADM,
            GID_NETADM, NULL) == -1) {
                err = EPERM;
                goto fail;
        }

        return (0);
fail:
        (void) ipmgmt_log(LOG_ERR, "failed to initialize the daemon: %s",
            strerror(err));
        return (err);
}

/*
 * Keep the pfds fd open, close other fds.
 */
/*ARGSUSED*/
static int
closefunc(void *arg, int fd)
{
        if (fd != pfds[1])
                (void) close(fd);
        return (0);
}

/*
 * We cannot use libc's daemon() because the door we create is associated with
 * the process ID. If we create the door before the call to daemon(), it will
 * be associated with the parent and it's incorrect. On the other hand if we
 * create the door later, after the call to daemon(), parent process exits
 * early and gives a false notion to SMF that 'ipmgmtd' is up and running,
 * which is incorrect. So, we have our own daemon() equivalent.
 */
static boolean_t
ipmgmt_daemonize(void)
{
        pid_t pid;
        int rv;

        if (pipe(pfds) < 0) {
                (void) fprintf(stderr, "%s: pipe() failed: %s\n",
                    progname, strerror(errno));
                exit(EXIT_FAILURE);
        }

        if ((pid = fork()) == -1) {
                (void) fprintf(stderr, "%s: fork() failed: %s\n",
                    progname, strerror(errno));
                exit(EXIT_FAILURE);
        } else if (pid > 0) { /* Parent */
                (void) close(pfds[1]);

                /*
                 * Parent should not exit early, it should wait for the child
                 * to return Success/Failure. If the parent exits early, then
                 * SMF will think 'ipmgmtd' is up and would start all the
                 * depended services.
                 *
                 * If the child process exits unexpectedly, read() returns -1.
                 */
                if (read(pfds[0], &rv, sizeof (int)) != sizeof (int)) {
                        (void) kill(pid, SIGKILL);
                        rv = EXIT_FAILURE;
                }

                (void) close(pfds[0]);
                exit(rv);
        }

        /* Child */
        (void) close(pfds[0]);
        (void) setsid();

        /* close all files except pfds[1] */
        (void) fdwalk(closefunc, NULL);
        (void) chdir("/");
        openlog(progname, LOG_PID, LOG_DAEMON);
        return (B_TRUE);
}

int
main(int argc, char *argv[])
{
        int opt;
        boolean_t fg = B_FALSE;

        progname = strrchr(argv[0], '/');
        if (progname != NULL)
                progname++;
        else
                progname = argv[0];

        /* Process options */
        while ((opt = getopt(argc, argv, "f")) != EOF) {
                switch (opt) {
                case 'f':
                        fg = B_TRUE;
                        break;
                default:
                        (void) fprintf(stderr, "Usage: %s [-f]\n", progname);
                        return (EXIT_FAILURE);
                }
        }

        if (!fg && getenv("SMF_FMRI") == NULL) {
                (void) fprintf(stderr,
                    "ipmgmtd is a smf(7) managed service and cannot be run "
                    "from the command line.\n");
                return (EINVAL);
        }

        if (!fg && !ipmgmt_daemonize())
                return (EXIT_FAILURE);

        if (ipmgmt_init_privileges() != 0)
                goto child_out;

        if (ipmgmt_init() != 0)
                goto child_out;

        /* Inform the parent process that it can successfully exit */
        ipmgmt_inform_parent_exit(EXIT_SUCCESS);

        for (;;)
                (void) pause();

child_out:
        /* return from main() forcibly exits an MT process */
        ipmgmt_inform_parent_exit(EXIT_FAILURE);
        return (EXIT_FAILURE);
}

/*
 * Persist any NGZ interfaces assigned to us from the global zone if they do
 * not already exist in the persistent db. We need to
 * do this before any calls to ipadm_enable_if() can succeed (i.e.,
 * before opening up for door_calls), and after setuid to 'netadm' so that
 * the persistent db is created with the right permissions.
 */
static void
ipmgmt_ngz_persist_if()
{
        ipmgmt_pif_t *pif, *next;
        ipmgmt_if_arg_t ifarg;

        for (pif = ngz_pifs; pif != NULL; pif = next) {
                next = pif->pif_next;
                bzero(&ifarg, sizeof (ifarg));
                (void) strlcpy(ifarg.ia_ifname, pif->pif_ifname,
                    sizeof (ifarg.ia_ifname));
                ifarg.ia_flags = IPMGMT_PERSIST;
                if (pif->pif_v4 &&
                    !ipmgmt_persist_if_exists(pif->pif_ifname, AF_INET)) {
                        ifarg.ia_family = AF_INET;
                        (void) ipmgmt_persist_if(&ifarg);
                }
                if (pif->pif_v6 &&
                    !ipmgmt_persist_if_exists(pif->pif_ifname, AF_INET6)) {
                        ifarg.ia_family = AF_INET6;
                        (void) ipmgmt_persist_if(&ifarg);
                }
                free(pif);
        }
        ngz_pifs = NULL; /* no red herrings */
}