proxy.c

snmp的源代码,已经在我的ubuntu下编译通过

/* Portions of this file are subject to the following copyright(s).  See
 * the Net-SNMP's COPYING file for more details and other copyrights
 * that may apply:
 */
/*
 * Portions of this file are copyrighted by:
 * Copyright @ 2003 Sun Microsystems, Inc. All rights reserved.
 * Use is subject to license terms specified in the COPYING file
 * distributed with the Net-SNMP package.
 */
#include <net-snmp/net-snmp-config.h>

#include <sys/types.h>
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

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

#include "proxy.h"

static struct simple_proxy *proxies = NULL;

oid             testoid[] = { 1, 3, 6, 1, 4, 1, 2021, 8888, 1 };

/*
 * this must be standardized somewhere, right? 
 */
#define MAX_ARGS 128

char           *context_string;

static void
proxyOptProc(int argc, char *const *argv, int opt)
{
    switch (opt) {
    case 'C':
        while (*optarg) {
            switch (*optarg++) {
            case 'n':
                optind++;
                if (optind < argc) {
                    context_string = argv[optind - 1];
                } else {
                    config_perror("No context name passed to -Cn");
                }
                break;
            case 'c':
                netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID,
                                       NETSNMP_DS_LIB_IGNORE_NO_COMMUNITY, 1);
                break;
            default:
                config_perror("unknown argument passed to -C");
                break;
            }
        }
        break;
    default:
        break;
        /*
         * shouldn't get here 
         */
    }
}

void
proxy_parse_config(const char *token, char *line)
{
    /*
     * proxy args [base-oid] [remap-to-remote-oid] 
     */

    netsnmp_session session, *ss;
    struct simple_proxy *newp, **listpp;
    char            args[MAX_ARGS][SPRINT_MAX_LEN], *argv[MAX_ARGS];
    int             argn, arg;
    char           *cp;
    netsnmp_handler_registration *reg;

    context_string = NULL;

    DEBUGMSGTL(("proxy_config", "entering\n"));

    /*
     * create the argv[] like array 
     */
    strcpy(argv[0] = args[0], "snmpd-proxy");   /* bogus entry for getopt() */
    for (argn = 1, cp = line; cp && argn < MAX_ARGS;) {
	argv[argn] = args[argn];
        cp = copy_nword(cp, argv[argn], SPRINT_MAX_LEN);
	argn++;
    }

    for (arg = 0; arg < argn; arg++) {
        DEBUGMSGTL(("proxy_args", "final args: %d = %s\n", arg,
                    argv[arg]));
    }

    DEBUGMSGTL(("proxy_config", "parsing args: %d\n", argn));
    /* Call special parse_args that allows for no specified community string */
    arg = snmp_parse_args(argn, argv, &session, "C:", proxyOptProc);

    /* reset this in case we modified it */
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID,
                           NETSNMP_DS_LIB_IGNORE_NO_COMMUNITY, 0);
    
    if (arg < 0) {
        config_perror("failed to parse proxy args");
        return;
    }
    DEBUGMSGTL(("proxy_config", "done parsing args\n"));

    if (arg >= argn) {
        config_perror("missing base oid");
        return;
    }

    SOCK_STARTUP;
    /*
     * usm_set_reportErrorOnUnknownID(0); 
     *
     * hack, stupid v3 ASIs. 
     */
    /*
     * XXX: on a side note, we don't really need to be a reference
     * platform any more so the proper thing to do would be to fix
     * snmplib/snmpusm.c to pass in the pdu type to usm_process_incoming
     * so this isn't needed. 
     */
    ss = snmp_open(&session);
    /*
     * usm_set_reportErrorOnUnknownID(1); 
     */
    if (ss == NULL) {
        /*
         * diagnose snmp_open errors with the input netsnmp_session pointer 
         */
        snmp_sess_perror("snmpget", &session);
        SOCK_CLEANUP;
        return;
    }

    newp = (struct simple_proxy *) calloc(1, sizeof(struct simple_proxy));

    newp->sess = ss;
    DEBUGMSGTL(("proxy_init", "name = %s\n", args[arg]));
    newp->name_len = MAX_OID_LEN;
    if (!snmp_parse_oid(args[arg++], newp->name, &newp->name_len)) {
        snmp_perror("proxy");
        config_perror("illegal proxy oid specified\n");
        return;
    }

    if (arg < argn) {
        DEBUGMSGTL(("proxy_init", "base = %s\n", args[arg]));
        newp->base_len = MAX_OID_LEN;
        if (!snmp_parse_oid(args[arg++], newp->base, &newp->base_len)) {
            snmp_perror("proxy");
            config_perror("illegal variable name specified (base oid)\n");
            return;
        }
    }
    if ( context_string )
        newp->context = strdup(context_string);

    DEBUGMSGTL(("proxy_init", "registering at: "));
    DEBUGMSGOID(("proxy_init", newp->name, newp->name_len));
    DEBUGMSG(("proxy_init", "\n"));

    /*
     * add to our chain 
     */
    /*
     * must be sorted! 
     */
    listpp = &proxies;
    while (*listpp &&
           snmp_oid_compare(newp->name, newp->name_len,
                            (*listpp)->name, (*listpp)->name_len) > 0) {
        listpp = &((*listpp)->next);
    }

    /*
     * listpp should be next in line from us. 
     */
    if (*listpp) {
        /*
         * make our next in the link point to the current link 
         */
        newp->next = *listpp;
    }
    /*
     * replace current link with us 
     */
    *listpp = newp;

    reg = netsnmp_create_handler_registration("proxy",
                                              proxy_handler,
                                              newp->name,
                                              newp->name_len,
                                              HANDLER_CAN_RWRITE);
    reg->handler->myvoid = newp;
    if (context_string)
        reg->contextName = strdup(context_string);

    netsnmp_register_handler(reg);
}

void
proxy_free_config(void)
{
    struct simple_proxy *rm;

    DEBUGMSGTL(("proxy_free_config", "Free config\n"));
    while (proxies) {
        rm = proxies;
        proxies = rm->next;

        DEBUGMSGTL(( "proxy_free_config", "freeing "));
        DEBUGMSGOID(("proxy_free_config", rm->name, rm->name_len));
        DEBUGMSG((   "proxy_free_config", " (%s)\n", rm->context));
        unregister_mib_context(rm->name, rm->name_len,
                               DEFAULT_MIB_PRIORITY, 0, 0,
                               rm->context);
        SNMP_FREE(rm->variables);
        SNMP_FREE(rm->context);
        snmp_close(rm->sess);
        SNMP_FREE(rm);
    }
}

/*
 * Configure special parameters on the session.
 * Currently takes the parameter configured and changes it if something 
 * was configured.  It becomes "-c" if the community string from the pdu
 * is placed on the session.
 */
int
proxy_fill_in_session(netsnmp_mib_handler *handler,
                      netsnmp_agent_request_info *reqinfo,
                      void **configured)
{
    netsnmp_session *session;
    struct simple_proxy *sp;

    sp = (struct simple_proxy *) handler->myvoid;
    if (!sp) {
        return 0;
    }
    session = sp->sess;
    if (!session) {
        return 0;
    }

#if !defined(DISABLE_SNMPV1) || !defined(DISABLE_SNMPV2C)
    if (session->version == SNMP_VERSION_1 ||
        session->version == SNMP_VERSION_2c) {

        /*
         * Check if session has community string defined for it.
         * If not, need to extract community string from the pdu.
         * Copy to session and set 'configured' to indicate this.
         */
        if (session->community_len == 0) {
            DEBUGMSGTL(("proxy", "session has no community string\n"));
            if (reqinfo->asp == NULL || reqinfo->asp->pdu == NULL ||
                reqinfo->asp->pdu->community_len == 0) {
                return 0;
            }

            *configured = malloc(strlen("-c") + 1);
            strcpy(*configured, "-c");
            DEBUGMSGTL(("proxy", "pdu has community string\n"));
            session->community_len = reqinfo->asp->pdu->community_len;
            session->community = malloc(session->community_len + 1);
            strncpy((char *)session->community,
                    (const char *)reqinfo->asp->pdu->community,
                    session->community_len);
        }
    }
#endif

    return 1;
}

/*
 * Free any specially configured parameters used on the session.
 */
void
proxy_free_filled_in_session_args(netsnmp_session *session, void **configured)
{

    /* Only do comparisions, etc., if something was configured */
    if (*configured == NULL) {
        return;
    }

    /* If used community string from pdu, release it from session now */
    if (strcmp((const char *)(*configured), "-c") == 0) {
        free(session->community);
        session->community = NULL;
        session->community_len = 0;
    }

    free((u_char *)(*configured));