smux.c

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                               &oid_name_len)) == NULL) {
        DEBUGMSGTL(("smux", "[smux_open_process] oid parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }
    snprint_objid(oid_print, sizeof(oid_print), oid_name, oid_name_len);

    if (snmp_get_do_debugging()) {
        DEBUGMSGTL(("smux", "[smux_open_process] smux peer: %s\n",
                    oid_print));
        DEBUGMSGTL(("smux", "[smux_open_process] len %d, type %d\n", *len,
                    (int) type));
    }

    string_len = SMUXMAXSTRLEN;
    if ((ptr = asn_parse_string(ptr, len, &type, (u_char *) descr,
                                &string_len)) == NULL) {
        DEBUGMSGTL(("smux", "[smux_open_process] descr parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }

    if (snmp_get_do_debugging()) {
        DEBUGMSGTL(("smux", "[smux_open_process] smux peer descr: "));
        for (i = 0; i < (int) string_len; i++)
            DEBUGMSG(("smux", "%c", descr[i]));
        DEBUGMSG(("smux", "\n"));
        DEBUGMSGTL(("smux", "[smux_open_process] len %d, type %d\n", *len,
                    (int) type));
    }
    descr[string_len] = 0;

    string_len = SMUXMAXSTRLEN;
    if ((ptr = asn_parse_string(ptr, len, &type, (u_char *) passwd,
                                &string_len)) == NULL) {
        DEBUGMSGTL(("smux", "[smux_open_process] passwd parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }

    if (snmp_get_do_debugging()) {
        DEBUGMSGTL(("smux", "[smux_open_process] smux peer passwd: "));
        for (i = 0; i < (int) string_len; i++)
            DEBUGMSG(("smux", "%c", passwd[i]));
        DEBUGMSG(("smux", "\n"));
        DEBUGMSGTL(("smux", "[smux_open_process] len %d, type %d\n", *len,
                    (int) type));
    }
    passwd[string_len] = '\0';
    if (!smux_auth_peer(oid_name, oid_name_len, passwd, fd)) {
        snmp_log(LOG_WARNING,
                 "refused smux peer: oid %s, descr %s\n",
                 oid_print, descr);
        *fail = TRUE;
        return ptr;
    }
    snmp_log(LOG_INFO,
             "accepted smux peer: oid %s, descr %s\n",
             oid_print, descr);
    *fail = FALSE;
    return ptr;
}

static void
smux_send_close(int fd, int reason)
{
    u_char          outpacket[3], *ptr;

    ptr = outpacket;

    *(ptr++) = (u_char) SMUX_CLOSE;
    *(ptr++) = (u_char) 1;
    *ptr = (u_char) (reason & 0xFF);

    if (snmp_get_do_debugging())
        DEBUGMSGTL(("smux",
                    "[smux_close] sending close to fd %d, reason %d\n", fd,
                    reason));

    /*
     * send a response back 
     */
    if (send(fd, (char *) outpacket, 3, 0) < 0) {
        snmp_log_perror("[smux_snmp_close] send failed");
    }
}


static int
smux_auth_peer(oid * name, size_t namelen, char *passwd, int fd)
{
    int             i;

    for (i = 0; i < nauths; i++) {
        if (snmp_oid_compare(Auths[i]->sa_oid, Auths[i]->sa_oid_len,
                             name, namelen) == 0) {
            if (!(strcmp(Auths[i]->sa_passwd, passwd)) &&
                (Auths[i]->sa_active_fd == -1)) {
                /*
                 * matched, mark the auth 
                 */
                Auths[i]->sa_active_fd = fd;
                return 1;
            }
        }
    }
    /*
     * did not match oid and passwd 
     */
    return 0;
}


/*
 * XXX - Bells and Whistles:
 * Need to catch signal when snmpd goes down and send close pdu to gated 
 */
static u_char  *
smux_close_process(int fd, u_char * ptr, size_t * len)
{
    long            down = 0;
    int             length = *len;

    /*
     * This is the integer part of the close pdu 
     */
    while (length--) {
        down = (down << 8) | (long) *ptr;
        ptr++;
    }

    DEBUGMSGTL(("smux",
                "[smux_close_process] close from peer on fd %d reason %d\n",
                fd, down));
    smux_peer_cleanup(fd);

    return NULL;
}

static u_char  *
smux_rreq_process(int sd, u_char * ptr, size_t * len)
{
    long            priority, rpriority;
    long            operation;
    oid             oid_name[MAX_OID_LEN];
    size_t          oid_name_len;
    int             i, result;
    u_char          type;
    smux_reg       *rptr, *nrptr;

    oid_name_len = MAX_OID_LEN;
    ptr = asn_parse_objid(ptr, len, &type, oid_name, &oid_name_len);

    DEBUGMSGTL(("smux", "[smux_rreq_process] smux subtree: "));
    DEBUGMSGOID(("smux", oid_name, oid_name_len));
    DEBUGMSG(("smux", "\n"));

    if ((ptr = asn_parse_int(ptr, len, &type, &priority,
                             sizeof(priority))) == NULL) {
        DEBUGMSGTL(("smux",
                    "[smux_rreq_process] priority parse failed\n"));
        smux_send_rrsp(sd, -1);
        return NULL;
    }
    DEBUGMSGTL(("smux", "[smux_rreq_process] priority %d\n", priority));

    if ((ptr = asn_parse_int(ptr, len, &type, &operation,
                             sizeof(operation))) == NULL) {
        DEBUGMSGTL(("smux",
                    "[smux_rreq_process] operation parse failed\n"));
        smux_send_rrsp(sd, -1);
        return NULL;
    }
    DEBUGMSGTL(("smux", "[smux_rreq_process] operation %d\n", operation));

    if (operation == SMUX_REGOP_DELETE) {
        /*
         * search the active list for this registration 
         */
        rptr =
            smux_find_match(ActiveRegs, sd, oid_name, oid_name_len,
                            priority);
        if (rptr) {
            rpriority = rptr->sr_priority;
            /*
             * unregister the mib 
             */
            unregister_mib(rptr->sr_name, rptr->sr_name_len);
            /*
             * find a replacement 
             */
            nrptr =
                smux_find_replacement(rptr->sr_name, rptr->sr_name_len);
            if (nrptr) {
                /*
                 * found one 
                 */
                smux_replace_active(rptr, nrptr);
            } else {
                /*
                 * no replacement found 
                 */
                smux_list_detach(&ActiveRegs, &rptr);
                free(rptr);
            }
            smux_send_rrsp(sd, rpriority);
            return ptr;
        }
        /*
         * search the passive list for this registration 
         */
        rptr =
            smux_find_match(PassiveRegs, sd, oid_name, oid_name_len,
                            priority);
        if (rptr) {
            rpriority = rptr->sr_priority;
            smux_list_detach(&PassiveRegs, &rptr);
            free(rptr);
            smux_send_rrsp(sd, rpriority);
            return ptr;
        }
        /*
         * This peer cannot unregister the tree, it does not
         * * belong to him.  Send him an error.
         */
        smux_send_rrsp(sd, -1);
        return ptr;

    } else if ((operation == SMUX_REGOP_REGISTER_RO) ||
               (operation == SMUX_REGOP_REGISTER_RW)) {
        if (priority < -1) {
            DEBUGMSGTL(("smux",
                        "[smux_rreq_process] peer fd %d invalid priority",
                        sd, priority));
            smux_send_rrsp(sd, -1);
            return NULL;
        }
        if ((nrptr = malloc(sizeof(smux_reg))) == NULL) {
            snmp_log_perror("[smux_rreq_process] malloc");
            smux_send_rrsp(sd, -1);
            return NULL;
        }
        nrptr->sr_priority = priority;
        nrptr->sr_name_len = oid_name_len;
        nrptr->sr_fd = sd;
        for (i = 0; i < (int) oid_name_len; i++)
            nrptr->sr_name[i] = oid_name[i];

        /*
         * See if this tree matches or scopes any of the
         * * active trees.
         */
        for (rptr = ActiveRegs; rptr; rptr = rptr->sr_next) {
            result =
                snmp_oid_compare(oid_name, oid_name_len, rptr->sr_name,
                                 rptr->sr_name_len);
            if (result == 0) {
                if ((oid_name_len == rptr->sr_name_len)) {
                    if ((nrptr->sr_priority == -1)) {
                        nrptr->sr_priority = rptr->sr_priority;
                        do {
                            nrptr->sr_priority++;
                        } while (smux_list_add(&PassiveRegs, nrptr));
                        goto done;
                    } else if (nrptr->sr_priority < rptr->sr_priority) {
                        /*
                         * Better priority.  There are no better
                         * * priorities for this tree in the passive list,
                         * * so replace the current active tree.
                         */
                        smux_replace_active(rptr, nrptr);
                        goto done;
                    } else {
                        /*
                         * Equal or worse priority 
                         */
                        do {
                            nrptr->sr_priority++;
                        } while (smux_list_add(&PassiveRegs, nrptr) == -1);
                        goto done;
                    }
                } else if (oid_name_len < rptr->sr_name_len) {
                    /*
                     * This tree scopes a current active
                     * * tree.  Replace the current active tree.
                     */
                    smux_replace_active(rptr, nrptr);
                    goto done;
                } else {        /* oid_name_len > rptr->sr_name_len */
                    /*
                     * This tree is scoped by a current
                     * * active tree.  
                     */
                    do {
                        nrptr->sr_priority++;
                    } while (smux_list_add(&PassiveRegs, nrptr) == -1);
                    goto done;
                }
            }
        }
        /*
         * We didn't find it in the active list.  Add it at
         * * the requested priority.
         */
        if (nrptr->sr_priority == -1)
            nrptr->sr_priority = 0;
        smux_list_add(&ActiveRegs, nrptr);
        register_mib("smux", (struct variable *)
                     smux_variables, sizeof(struct variable2),
                     1, nrptr->sr_name, nrptr->sr_name_len);
      done:
        smux_send_rrsp(sd, nrptr->sr_priority);
        return ptr;
    } else {
        DEBUGMSGTL(("smux", "[smux_rreq_process] unknown operation\n"));
        smux_send_rrsp(sd, -1);
        return NULL;
    }
}

/*
 * Find the registration with a matching descriptor, OID and priority.  If
 * the priority is -1 then find a registration with a matching descriptor,
 * a matching OID, and the highest priority.
 */
static smux_reg *
smux_find_match(smux_reg * regs, int sd, oid * oid_name,
                size_t oid_name_len, long priority)
{
    smux_reg       *rptr, *bestrptr;

    bestrptr = NULL;
    for (rptr = regs; rptr; rptr = rptr->sr_next) {
        if (rptr->sr_fd != sd)
            continue;
        if (snmp_oid_compare
            (rptr->sr_name, rptr->sr_name_len, oid_name, oid_name_len))
            continue;
        if (rptr->sr_priority == priority)
            return rptr;
        if (priority != -1)
            continue;
        if (bestrptr) {
            if (bestrptr->sr_priority > rptr->sr_priority)
                bestrptr = rptr;
        } else {
            bestrptr = rptr;
        }
    }
    return bestrptr;
}

static void
smux_replace_active(smux_reg * actptr, smux_reg * pasptr)
{
    smux_list_detach(&ActiveRegs, &actptr);
    unregister_mib(actptr->sr_name, actptr->sr_name_len);

    smux_list_detach(&PassiveRegs, &pasptr);
    (void) smux_list_add(&ActiveRegs, pasptr);

    register_mib("smux", (struct variable *) smux_variables,
                 sizeof(struct variable2), 1, pasptr->sr_name,
                 pasptr->sr_name_len);
    free(actptr);
}

static void
smux_list_detach(smux_reg ** head, smux_reg ** m_remove)
{
    smux_reg       *rptr, *rptr2;

    if (*head == NULL) {
        DEBUGMSGTL(("smux", "[smux_list_detach] Ouch!"));
        return;
    }
    if (*head == *m_remove) {
        *m_remove = *head;
        *head = (*head)->sr_next;
        return;
    }
    for (rptr = *head, rptr2 = rptr->sr_next; rptr2;
         rptr2 = rptr2->sr_next, rptr = rptr->sr_next) {
        if (rptr2 == *m_remove) {
            *m_remove = rptr2;
            rptr->sr_next = rptr2->sr_next;
            return;
        }
    }
}

/*
 * Attempt to add a registration (in order) to a list.  If the
 * add fails (because of an existing registration with equal
 * priority) return -1.
 */
static int
smux_list_add(smux_reg ** head, smux_reg * add)
{
    smux_reg       *rptr, *prev;
    int             result;

    if (*head == NULL) {
        *head = add;
        (*head)->sr_next = NULL;
        return 0;
    }
    prev = NULL;
    for (rptr = *head; rptr->sr_next; rptr = rptr->sr_next) {
        result = snmp_oid_compare(add->sr_name, add->sr_name_len,
                                  rptr->sr_name, rptr->sr_name_len);
        if ((result == 0) && (add->sr_priority == rptr->sr_priority)) {
            /*
             * same tree, same pri, nope 
             */
            return -1;