usr.lib/pppoe/pppoed.c

/*
 * 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);
}