smux.c

开发snmp的开发包有两个开放的SNMP开发库

/*
 * Smux module authored by Rohit Dube.
 * Rewritten by Nick Amato <[e-mail]>.
 */

#include <net-snmp/net-snmp-config.h>
#include <sys/types.h>
#include <ctype.h>

#if HAVE_IO_H                   /* win32 */
#include <io.h>
#endif
#include <stdio.h>
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_ERR_H
#include <err.h>
#endif
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
#  include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#include <errno.h>
#if HAVE_NETDB_H
#include <netdb.h>
#endif

#include <sys/stat.h>
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#elif HAVE_WINSOCK_H
#include <winsock.h>
#endif
#if HAVE_SYS_FILIO_H
#include <sys/filio.h>
#endif

#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif

#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <net-snmp/library/tools.h>

#include "smux.h"
#include "util_funcs.h"
#include "mibdefs.h"
#include "snmpd.h"

long            smux_long;
u_long          smux_ulong;
struct sockaddr_in smux_sa;
struct counter64 smux_counter64;
oid             smux_objid[MAX_OID_LEN];
u_char          smux_str[SMUXMAXSTRLEN];
int             smux_listen_sd = -1;

static struct timeval smux_rcv_timeout;
static long   smux_reqid;

void            init_smux(void);
static u_char  *smux_open_process(int, u_char *, size_t *, int *);
static u_char  *smux_rreq_process(int, u_char *, size_t *);
static u_char  *smux_close_process(int, u_char *, size_t *);
static u_char  *smux_trap_process(u_char *, size_t *);
static u_char  *smux_parse(u_char *, oid *, size_t *, size_t *, u_char *);
static u_char  *smux_parse_var(u_char *, size_t *, oid *, size_t *,
                               size_t *, u_char *);
static void     smux_send_close(int, int);
static void     smux_list_detach(smux_reg **, smux_reg **);
static void     smux_replace_active(smux_reg *, smux_reg *);
static void     smux_peer_cleanup(int);
static int      smux_auth_peer(oid *, size_t, char *, int);
static int      smux_build(u_char, long, oid *,
                           size_t *, u_char, u_char *, size_t, u_char *,
                           size_t *);
static int      smux_list_add(smux_reg **, smux_reg *);
static int      smux_pdu_process(int, u_char *, size_t);
static int      smux_send_rrsp(int, int);
static smux_reg *smux_find_match(smux_reg *, int, oid *, size_t, long);
static smux_reg *smux_find_replacement(oid *, size_t);
u_char         *var_smux(struct variable *, oid *, size_t *, int, size_t *,
                         WriteMethod ** write_method);
int             var_smux_write(int, u_char *, u_char, size_t, u_char *,
                               oid *, size_t);

static smux_reg *ActiveRegs;    /* Active registrations                 */
static smux_reg *PassiveRegs;   /* Currently unused registrations       */

static smux_peer_auth *Auths[SMUX_MAX_PEERS];   /* Configured peers */
static int      nauths, npeers = 0;

struct variable2 smux_variables[] = {
    /*
     * bogus entry, as in pass.c 
     */
    {MIBINDEX, ASN_INTEGER, RWRITE, var_smux, 0, {MIBINDEX}},
};



void
smux_parse_smux_socket(const char *token, char *cptr)
{
    DEBUGMSGTL(("smux", "port spec: %s\n", cptr));
    netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_SMUX_SOCKET, cptr);
}

void
smux_parse_peer_auth(const char *token, char *cptr)
{
    smux_peer_auth *aptr;
    char           *password_cptr;
    int             cptr_len;

    if ((aptr =
         (smux_peer_auth *) calloc(1, sizeof(smux_peer_auth))) == NULL) {
        snmp_log_perror("smux_parse_peer_auth: malloc");
        return;
    }
    if (nauths == SMUX_MAX_PEERS) {
	config_perror("Too many smuxpeers");
	return;
    }

    /*
     * oid 
     */
    aptr->sa_active_fd = -1;
    aptr->sa_oid_len = MAX_OID_LEN;
    read_objid( cptr, aptr->sa_oid, &aptr->sa_oid_len );
    DEBUGMSGTL(("smux_conf", "parsing registration for: %s\n", cptr));

    password_cptr = strchr(cptr, ' ');
    cptr_len = strlen(cptr);

    if (password_cptr != NULL) {    /* Do we have a password or not? */
        *password_cptr = 0x0;
	if ((&password_cptr - &cptr + 1) < cptr_len) {
	    cptr = ++password_cptr;
	    DEBUGMSGTL(("smux_conf", "password is: %s\n",
	                SNMP_STRORNULL(cptr)));
	}

        /*
         * password 
         */
        if (cptr)
            strcpy(aptr->sa_passwd, cptr);
    } else {
        /*
         * null passwords OK 
         */
        DEBUGMSGTL(("smux_conf", "null password\n"));
    }

    Auths[nauths++] = aptr;
    return;
}

void
smux_free_peer_auth(void)
{
    int             i;

    for (i = 0; i < nauths; i++) {
        free(Auths[i]);
        Auths[i] = NULL;
    }
    nauths = 0;
}

void
init_smux(void)
{
    snmpd_register_config_handler("smuxpeer", smux_parse_peer_auth,
                                  smux_free_peer_auth,
                                  "OID-IDENTITY PASSWORD");
    snmpd_register_config_handler("smuxsocket",
                                  smux_parse_smux_socket, NULL,
                                  "SMUX bind address");
}

void
real_init_smux(void)
{
    struct sockaddr_in lo_socket;
    char           *smux_socket;
    int             one = 1;

    if (netsnmp_ds_get_boolean(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_ROLE) == SUB_AGENT) {
        smux_listen_sd = -1;
        return;
    }

    /*
     * Reqid 
     */
    smux_reqid = 0;
    smux_listen_sd = -1;

    /*
     * Receive timeout 
     */
    smux_rcv_timeout.tv_sec = 0;
    smux_rcv_timeout.tv_usec = 500000;

    /*
     * Get ready to listen on the SMUX port
     */
    memset(&lo_socket, (0), sizeof(lo_socket));
    lo_socket.sin_family = AF_INET;

    smux_socket = netsnmp_ds_get_string(NETSNMP_DS_APPLICATION_ID, 
					NETSNMP_DS_SMUX_SOCKET);
#ifdef NETSNMP_ENABLE_LOCAL_SMUX
    if (!smux_socket)
        smux_socket = "127.0.0.1";   /* By default, listen on localhost only */
#endif
    netsnmp_sockaddr_in( &lo_socket, smux_socket, SMUXPORT );

    if ((smux_listen_sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        snmp_log_perror("[init_smux] socket failed");
        return;
    }
#ifdef SO_REUSEADDR
    /*
     * At least on Linux, when the master agent terminates, any
     * TCP connections for SMUX peers are put in the TIME_WAIT
     * state for about 60 seconds. If the master agent is started
     * during this time, the bind for the listening socket will
     * fail because the SMUX port is in use.
     */
    if (setsockopt(smux_listen_sd, SOL_SOCKET, SO_REUSEADDR, (char *) &one,
                   sizeof(one)) < 0) {
        snmp_log_perror("[init_smux] setsockopt(SO_REUSEADDR) failed");
    }
#endif                          /* SO_REUSEADDR */

    if (bind(smux_listen_sd, (struct sockaddr *) &lo_socket,
             sizeof(lo_socket)) < 0) {
        snmp_log_perror("[init_smux] bind failed");
        close(smux_listen_sd);
        smux_listen_sd = -1;
        return;
    }
#ifdef	SO_KEEPALIVE
    if (setsockopt(smux_listen_sd, SOL_SOCKET, SO_KEEPALIVE, (char *) &one,
                   sizeof(one)) < 0) {
        snmp_log_perror("[init_smux] setsockopt(SO_KEEPALIVE) failed");
        close(smux_listen_sd);
        smux_listen_sd = -1;
        return;
    }
#endif                          /* SO_KEEPALIVE */

    if (listen(smux_listen_sd, SOMAXCONN) == -1) {
        snmp_log_perror("[init_smux] listen failed");
        close(smux_listen_sd);
        smux_listen_sd = -1;
        return;
    }

    DEBUGMSGTL(("smux_init",
                "[smux_init] done; smux listen sd is %d, smux port is %d\n",
                smux_listen_sd, ntohs(lo_socket.sin_port)));
}

u_char         *
var_smux(struct variable * vp,
         oid * name,
         size_t * length,
         int exact, size_t * var_len, WriteMethod ** write_method)
{
    u_char         *valptr, val_type;
    smux_reg       *rptr;

    *write_method = var_smux_write;
    /*
     * search the active registration list 
     */
    for (rptr = ActiveRegs; rptr; rptr = rptr->sr_next) {
        if (0 >= snmp_oidtree_compare(vp->name, vp->namelen, rptr->sr_name,
                                      rptr->sr_name_len))
            break;
    }
    if (rptr == NULL)
        return NULL;
    else if (exact && (*length < rptr->sr_name_len))
        return NULL;

    valptr = smux_snmp_process(exact, name, length,
                               var_len, &val_type, rptr->sr_fd);

    if (valptr == NULL)
        return NULL;

    if ((snmp_oidtree_compare(name, *length, rptr->sr_name,
                              rptr->sr_name_len)) != 0) {
        /*
         * the peer has returned a value outside
         * * of the registered tree
         */
        return NULL;
    } else {
        /*
         * set the type and return the value 
         */
        vp->type = val_type;
        return valptr;
    }
}

int
var_smux_write(int action,
               u_char * var_val,
               u_char var_val_type,
               size_t var_val_len,
               u_char * statP, oid * name, size_t name_len)
{
    smux_reg       *rptr;
    u_char          buf[SMUXMAXPKTSIZE], *ptr, sout[3], type;
    int             reterr;
    size_t          var_len, datalen, name_length, packet_len;
    ssize_t         len, tmp_len;
    long            reqid, errsts, erridx;
    u_char          var_type, *dataptr;

    DEBUGMSGTL(("smux", "[var_smux_write] entering var_smux_write\n"));

    len = SMUXMAXPKTSIZE;
    reterr = SNMP_ERR_NOERROR;
    var_len = var_val_len;
    var_type = var_val_type;
    name_length = name_len;

    /*
     * XXX find the descriptor again 
     */
    for (rptr = ActiveRegs; rptr; rptr = rptr->sr_next) {
        if (!snmp_oidtree_compare(name, name_len, rptr->sr_name,
                                  rptr->sr_name_len))
            break;
    }

    switch (action) {
    case RESERVE1:
        DEBUGMSGTL(("smux", "[var_smux_write] entering RESERVE1\n"));

        /*
         * length might be long 
         */
        var_len += (*(var_val + 1) & ASN_LONG_LEN) ?
            var_len + ((*(var_val + 1) & 0x7F) + 2) : 2;

        switch (var_val_type) {
        case ASN_INTEGER:
        case ASN_OCTET_STR:
        case ASN_COUNTER:
        case ASN_GAUGE:
        case ASN_TIMETICKS:
        case ASN_UINTEGER:
        case ASN_COUNTER64:
        case ASN_IPADDRESS:
        case ASN_OPAQUE:
        case ASN_NSAP:
        case ASN_OBJECT_ID:
        case ASN_BIT_STR:
            datalen = var_val_len;
            dataptr = var_val;
            break;
        case SNMP_NOSUCHOBJECT:
        case SNMP_NOSUCHINSTANCE:
        case SNMP_ENDOFMIBVIEW:
        case ASN_NULL:
        default:
            DEBUGMSGTL(("smux",
                        "[var_smux_write] variable not supported\n"));
            return SNMP_ERR_GENERR;
            break;
        }

        if ((smux_build((u_char) SMUX_SET, smux_reqid,
                        name, &name_length, var_val_type, dataptr,
                        datalen, buf, &len)) < 0) {
            DEBUGMSGTL(("smux", "[var_smux_write] smux build failed\n"));
            return SNMP_ERR_GENERR;
        }