/*
 * 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
 */
/*
 * PPPoE Server-mode daemon for use with Solaris PPP 4.0.
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <stropts.h>
#include <wait.h>
#include <sys/resource.h>
#include <netinet/in.h>
#include <net/sppptun.h>
#include <net/pppoe.h>

#include "common.h"
#include "pppoed.h"
#include "logging.h"

static int tunfd;               /* Global connection to tunnel device */

char *myname;                   /* Copied from argv[0] for logging */
static int main_argc;           /* Saved for reparse on SIGHUP */
static char **main_argv;        /* Saved for reparse on SIGHUP */

static time_t time_started;     /* Time daemon was started; for debug */
static time_t last_reread;      /* Last time configuration was read. */

/* Various operational statistics. */
static unsigned long input_packets, padi_packets, padr_packets;
static unsigned long output_packets;
static unsigned long sessions_started;

static sigset_t sigmask;        /* Global signal mask */

/*
 * Used for handling errors that occur before we daemonize.
 */
static void
early_error(const char *str)
{
        const char *cp;

        cp = mystrerror(errno);
        if (isatty(2)) {
                (void) fprintf(stderr, "%s: %s: %s\n", myname, str, cp);
        } else {
                reopen_log();
                logerr("%s: %s", str, cp);
        }
        exit(1);
}

/*
 * Open the sppptun driver.
 */
static void
open_tunnel_dev(void)
{
        struct ppptun_peer ptp;

        tunfd = open(tunnam, O_RDWR);
        if (tunfd == -1) {
                early_error(tunnam);
        }

        /*
         * Tell the device driver that I'm a daemon handling inbound
         * connections, not a PPP session.
         */
        (void) memset(&ptp, '\0', sizeof (ptp));
        ptp.ptp_style = PTS_PPPOE;
        ptp.ptp_flags = PTPF_DAEMON;
        (void) memcpy(ptp.ptp_address.pta_pppoe.ptma_mac, ether_bcast,
            sizeof (ptp.ptp_address.pta_pppoe.ptma_mac));
        if (strioctl(tunfd, PPPTUN_SPEER, &ptp, sizeof (ptp), sizeof (ptp)) <
            0) {
                myperror("PPPTUN_SPEER");
                exit(1);
        }
}

/*
 * Callback function for fdwalk.  Closes everything but the tunnel
 * file descriptor when becoming daemon.  (Log file must be reopened
 * manually, since syslog file descriptor, if any, is unknown.)
 */
/*ARGSUSED*/
static int
fdcloser(void *arg, int fd)
{
        if (fd != tunfd)
                (void) close(fd);
        return (0);
}

/*
 * Become a daemon.
 */
static void
daemonize(void)
{
        pid_t cpid;

        /*
         * A little bit of magic here.  By the first fork+setsid, we
         * disconnect from our current controlling terminal and become
         * a session group leader.  By forking again without setsid,
         * we make certain that we're not the session group leader and
         * can never reacquire a controlling terminal.
         */
        if ((cpid = fork()) == (pid_t)-1) {
                early_error("fork 1");
        }
        if (cpid != 0) {
                (void) wait(NULL);
                _exit(0);
        }
        if (setsid() == (pid_t)-1) {
                early_error("setsid");
        }
        if ((cpid = fork()) == (pid_t)-1) {
                early_error("fork 2");
        }
        if (cpid != 0) {
                /* Parent just exits */
                (void) printf("%d\n", (int)cpid);
                (void) fflush(stdout);
                _exit(0);
        }
        (void) chdir("/");
        (void) umask(0);
        (void) fdwalk(fdcloser, NULL);
        reopen_log();
}

/*
 * Handle SIGHUP -- close and reopen non-syslog log files and reparse
 * options.
 */
/*ARGSUSED*/
static void
handle_hup(int sig)
{
        close_log_files();
        global_logging();
        last_reread = time(NULL);
        parse_options(tunfd, main_argc, main_argv);
}

/*
 * Handle SIGINT -- write current daemon status to /tmp.
 */
/*ARGSUSED*/
static void
handle_int(int sig)
{
        FILE *fp;
        char dumpname[MAXPATHLEN];
        time_t now;
        struct rusage rusage;

        (void) snprintf(dumpname, sizeof (dumpname), "/tmp/pppoed.%ld",
            getpid());
        if ((fp = fopen(dumpname, "w+")) == NULL) {
                logerr("%s: %s", dumpname, mystrerror(errno));
                return;
        }
        now = time(NULL);
        (void) fprintf(fp, "pppoed running %s", ctime(&now));
        (void) fprintf(fp, "Started on     %s", ctime(&time_started));
        if (last_reread != 0)
                (void) fprintf(fp, "Last reconfig  %s", ctime(&last_reread));
        (void) putc('\n', fp);
        if (getrusage(RUSAGE_SELF, &rusage) == 0) {
                (void) fprintf(fp,
                    "CPU usage:  user %ld.%06ld, system %ld.%06ld\n",
                    rusage.ru_utime.tv_sec, rusage.ru_utime.tv_usec,
                    rusage.ru_stime.tv_sec, rusage.ru_stime.tv_usec);
        }
        (void) fprintf(fp, "Packets:  %lu received (%lu PADI, %lu PADR), ",
            input_packets, padi_packets, padr_packets);
        (void) fprintf(fp, "%lu transmitted\n", output_packets);
        (void) fprintf(fp, "Sessions started:  %lu\n\n", sessions_started);
        dump_configuration(fp);
        (void) fclose(fp);
}

static void
add_signal_handlers(void)
{
        struct sigaction sa;

        (void) sigemptyset(&sigmask);
        (void) sigaddset(&sigmask, SIGHUP);
        (void) sigaddset(&sigmask, SIGCHLD);
        (void) sigaddset(&sigmask, SIGINT);
        (void) sigprocmask(SIG_BLOCK, &sigmask, NULL);

        sa.sa_mask = sigmask;
        sa.sa_flags = 0;

        /* Signals to handle */
        sa.sa_handler = handle_hup;
        if (sigaction(SIGHUP, &sa, NULL) < 0)
                early_error("sigaction HUP");
        sa.sa_handler = handle_int;
        if (sigaction(SIGINT, &sa, NULL) < 0)
                early_error("sigaction INT");

        /*
         * Signals to ignore.  Ignoring SIGCHLD in this way makes the
         * children exit without ever creating zombies.  (No wait(2)
         * call required.)
         */
        sa.sa_handler = SIG_IGN;
        if (sigaction(SIGPIPE, &sa, NULL) < 0)
                early_error("sigaction PIPE");
        sa.sa_flags = SA_NOCLDWAIT;
        if (sigaction(SIGCHLD, &sa, NULL) < 0)
                early_error("sigaction CHLD");
}

/*
 * Dispatch a message from the tunnel driver.  It could be an actual
 * PPPoE message or just an event notification.
 */
static void
handle_input(uint32_t *ctrlbuf, int ctrllen, uint32_t *databuf, int datalen)
{
        poep_t *poep = (poep_t *)databuf;
        union ppptun_name ptn;
        int retv;
        struct strbuf ctrl;
        struct strbuf data;
        void *srvp;
        boolean_t launch;
        struct ppptun_control *ptc;

        if (ctrllen != sizeof (*ptc)) {
                logdbg("bogus %d byte control message from driver",
                    ctrllen);
                return;
        }
        ptc = (struct ppptun_control *)ctrlbuf;

        /* Switch out on event notifications. */
        switch (ptc->ptc_action) {
        case PTCA_TEST:
                logdbg("test reply for discriminator %X", ptc->ptc_discrim);
                return;

        case PTCA_CONTROL:
                break;

        case PTCA_DISCONNECT:
                logdbg("session %d disconnected on %s; send PADT",
                    ptc->ptc_rsessid, ptc->ptc_name);
                poep = poe_mkheader(pkt_output, POECODE_PADT,
                    ptc->ptc_rsessid);
                ptc->ptc_action = PTCA_CONTROL;
                ctrl.len = sizeof (*ptc);
                ctrl.buf = (caddr_t)ptc;
                data.len = poe_length(poep) + sizeof (*poep);
                data.buf = (caddr_t)poep;
                if (putmsg(tunfd, &ctrl, &data, 0) < 0) {
                        logerr("putmsg PADT: %s", mystrerror(errno));
                } else {
                        output_packets++;
                }
                return;

        case PTCA_UNPLUMB:
                logdbg("%s unplumbed", ptc->ptc_name);
                return;

        case PTCA_BADCTRL:
                logwarn("bad control data on %s for session %u", ptc->ptc_name,
                    ptc->ptc_rsessid);
                return;

        default:
                logdbg("unexpected code %d from driver", ptc->ptc_action);
                return;
        }

        /* Only PPPoE control messages get here. */

        input_packets++;
        if (datalen < sizeof (*poep)) {
                logdbg("incomplete PPPoE message from %s/%s",
                    ehost(&ptc->ptc_address), ptc->ptc_name);
                return;
        }

        /* Server handles only PADI and PADR; all others are ignored. */
        if (poep->poep_code == POECODE_PADI) {
                padi_packets++;
        } else if (poep->poep_code == POECODE_PADR) {
                padr_packets++;
        } else {
                loginfo("unexpected %s from %s",
                    poe_codename(poep->poep_code), ehost(&ptc->ptc_address));
                return;
        }
        logdbg("Recv from %s/%s: %s", ehost(&ptc->ptc_address), ptc->ptc_name,
            poe_codename(poep->poep_code));

        /* Parse out service and formulate template reply. */
        retv = locate_service(poep, datalen, ptc->ptc_name, &ptc->ptc_address,
            pkt_output, &srvp);

        /* Continue formulating reply */
        launch = B_FALSE;
        if (retv != 1) {
                /* Ignore initiation if we don't offer a service. */
                if (retv <= 0 && poep->poep_code == POECODE_PADI) {
                        logdbg("no services; no reply");
                        return;
                }
                if (retv == 0)
                        (void) poe_add_str((poep_t *)pkt_output, POETT_NAMERR,
                            "No such service.");
        } else {
                /* Exactly one service chosen; if it's PADR, then we start. */
                if (poep->poep_code == POECODE_PADR) {
                        launch = B_TRUE;
                }
        }
        poep = (poep_t *)pkt_output;

        /* Select control interface for output. */
        (void) strncpy(ptn.ptn_name, ptc->ptc_name, sizeof (ptn.ptn_name));
        if (strioctl(tunfd, PPPTUN_SCTL, &ptn, sizeof (ptn), 0) < 0) {
                logerr("PPPTUN_SCTL %s: %s", ptn.ptn_name, mystrerror(errno));
                return;
        }

        /* Launch the PPP service */
        if (launch && launch_service(tunfd, poep, srvp, ptc))
                sessions_started++;

        /* Send the reply. */
        ctrl.len = sizeof (*ptc);
        ctrl.buf = (caddr_t)ptc;
        data.len = poe_length(poep) + sizeof (*poep);
        data.buf = (caddr_t)poep;
        if (putmsg(tunfd, &ctrl, &data, 0) < 0) {
                logerr("putmsg %s: %s", ptc->ptc_name, mystrerror(errno));
        } else {
                output_packets++;
                logdbg("Send to   %s/%s: %s", ehost(&ptc->ptc_address),
                    ptc->ptc_name, poe_codename(poep->poep_code));
        }
}

static void
main_loop(void)
{
        struct strbuf ctrl;
        struct strbuf data;
        int flags;
        int rc;
        int err;

        for (;;) {
                ctrl.maxlen = PKT_OCTL_LEN;
                ctrl.buf = (caddr_t)pkt_octl;
                data.maxlen = PKT_INPUT_LEN;
                data.buf = (caddr_t)pkt_input;
                /* Allow signals only while idle */
                (void) sigprocmask(SIG_UNBLOCK, &sigmask, NULL);
                errno = 0;
                flags = 0;
                rc = mygetmsg(tunfd, &ctrl, &data, &flags);
                err = errno;
                /*
                 * Block signals -- data structures must not change
                 * while we're busy dispatching the client's request
                 */
                (void) sigprocmask(SIG_BLOCK, &sigmask, NULL);
                if (rc == -1) {
                        if (err == EAGAIN || err == EINTR)
                                continue;
                        logerr("%s getmsg: %s", tunnam, mystrerror(err));
                        exit(1);
                }
                if (rc > 0)
                        logwarn("%s returned truncated data", tunnam);
                else
                        handle_input(pkt_octl, ctrl.len, pkt_input, data.len);
        }
}

int
main(int argc, char **argv)
{
        prog_name = "pppoed";
        log_level = 1;          /* Default to error messages only at first */

        time_started = time(NULL);

        if ((myname = argv[0]) == NULL)
                myname = "pppoed";

        main_argc = argc;
        main_argv = argv;

        open_tunnel_dev();
        add_signal_handlers();
        daemonize();

        parse_options(tunfd, argc, argv);
        main_loop();

        return (0);
}