3c54eb0587
populate it. Not doing this can result in a garbage sockaddr_in, which will cause connect() to block inside clnttcp_create().
502 lines
13 KiB
C
502 lines
13 KiB
C
#pragma ident "@(#)auth_time.c 1.4 92/11/10 SMI"
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/*
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* auth_time.c
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*
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* This module contains the private function __rpc_get_time_offset()
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* which will return the difference in seconds between the local system's
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* notion of time and a remote server's notion of time. This must be
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* possible without calling any functions that may invoke the name
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* service. (netdir_getbyxxx, getXbyY, etc). The function is used in the
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* synchronize call of the authdes code to synchronize clocks between
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* NIS+ clients and their servers.
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*
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* Note to minimize the amount of duplicate code, portions of the
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* synchronize() function were folded into this code, and the synchronize
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* call becomes simply a wrapper around this function. Further, if this
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* function is called with a timehost it *DOES* recurse to the name
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* server so don't use it in that mode if you are doing name service code.
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*
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* Copyright (c) 1992 Sun Microsystems Inc.
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* All rights reserved.
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*
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* Side effects :
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* When called a client handle to a RPCBIND process is created
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* and destroyed. Two strings "netid" and "uaddr" are malloc'd
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* and returned. The SIGALRM processing is modified only if
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* needed to deal with TCP connections.
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*
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* NOTE: This code has had the crap beaten out it in order to convert
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* it from TI-RPC back to TD-RPC for use on FreeBSD.
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*/
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#include <stdio.h>
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#include <syslog.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <netdb.h>
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#include <sys/signal.h>
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#include <sys/errno.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <rpc/rpc.h>
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#include <rpc/rpc_com.h>
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#undef NIS
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#include <rpcsvc/nis.h>
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/*
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* FreeBSD currently uses RPC 4.0, which uses portmap rather than
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* rpcbind. Consequently, we need to fake up these values here.
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* Luckily, the RPCB_GETTIME procedure uses only base XDR data types
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* so we don't need anything besides these magic numbers.
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*/
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#define RPCBPROG (u_long)100000
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#define RPCBVERS (u_long)3
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#define RPCBPROC_GETTIME (u_long)6
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#ifdef TESTING
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#define msg(x) printf("ERROR: %s\n", x)
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/* #define msg(x) syslog(LOG_ERR, "%s", x) */
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#else
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#define msg(x)
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#endif
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static int saw_alarm = 0;
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static void
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alarm_hndler(s)
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int s;
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{
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saw_alarm = 1;
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return;
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}
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/*
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* The internet time server defines the epoch to be Jan 1, 1900
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* whereas UNIX defines it to be Jan 1, 1970. To adjust the result
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* from internet time-service time, into UNIX time we subtract the
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* following offset :
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*/
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#define NYEARS (1970 - 1900)
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#define TOFFSET ((u_long)60*60*24*(365*NYEARS + (NYEARS/4)))
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/*
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* Stolen from rpc.nisd:
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* Turn a 'universal address' into a struct sockaddr_in.
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* Bletch.
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*/
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static int uaddr_to_sockaddr(uaddr, sin)
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#ifdef foo
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endpoint *endpt;
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#endif
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char *uaddr;
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struct sockaddr_in *sin;
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{
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unsigned char p_bytes[2];
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int i;
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unsigned long a[6];
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i = sscanf(uaddr, "%lu.%lu.%lu.%lu.%lu.%lu", &a[0], &a[1], &a[2],
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&a[3], &a[4], &a[5]);
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if (i < 6)
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return(1);
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for (i = 0; i < 4; i++)
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sin->sin_addr.s_addr |= (a[i] & 0x000000FF) << (8 * i);
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p_bytes[0] = (unsigned char)a[4] & 0x000000FF;
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p_bytes[1] = (unsigned char)a[5] & 0x000000FF;
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sin->sin_family = AF_INET; /* always */
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bcopy((char *)&p_bytes, (char *)&sin->sin_port, 2);
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return (0);
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}
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/*
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* free_eps()
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*
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* Free the strings that were strduped into the eps structure.
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*/
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static void
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free_eps(eps, num)
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endpoint eps[];
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int num;
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{
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int i;
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for (i = 0; i < num; i++) {
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free(eps[i].uaddr);
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free(eps[i].proto);
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free(eps[i].family);
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}
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return;
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}
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/*
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* get_server()
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*
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* This function constructs a nis_server structure description for the
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* indicated hostname.
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*
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* NOTE: There is a chance we may end up recursing here due to the
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* fact that gethostbyname() could do an NIS search. Ideally, the
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* NIS+ server will call __rpc_get_time_offset() with the nis_server
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* structure already populated.
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*/
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static nis_server *
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get_server(sin, host, srv, eps, maxep)
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struct sockaddr_in *sin;
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char *host; /* name of the time host */
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nis_server *srv; /* nis_server struct to use. */
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endpoint eps[]; /* array of endpoints */
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int maxep; /* max array size */
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{
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char hname[256];
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int num_ep = 0, i;
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struct hostent *he;
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struct hostent dummy;
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char *ptr[2];
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if (host == NULL && sin == NULL)
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return (NULL);
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if (sin == NULL) {
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he = gethostbyname(host);
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if (he == NULL)
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return(NULL);
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} else {
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he = &dummy;
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ptr[0] = (char *)&sin->sin_addr.s_addr;
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ptr[1] = NULL;
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dummy.h_addr_list = ptr;
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}
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/*
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* This is lame. We go around once for TCP, then again
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* for UDP.
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*/
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for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
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i++, num_ep++) {
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struct in_addr *a;
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a = (struct in_addr *)he->h_addr_list[i];
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snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
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eps[num_ep].uaddr = strdup(hname);
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eps[num_ep].family = strdup("inet");
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eps[num_ep].proto = strdup("tcp");
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}
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for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
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i++, num_ep++) {
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struct in_addr *a;
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a = (struct in_addr *)he->h_addr_list[i];
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snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
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eps[num_ep].uaddr = strdup(hname);
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eps[num_ep].family = strdup("inet");
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eps[num_ep].proto = strdup("udp");
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}
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srv->name = (nis_name) host;
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srv->ep.ep_len = num_ep;
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srv->ep.ep_val = eps;
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srv->key_type = NIS_PK_NONE;
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srv->pkey.n_bytes = NULL;
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srv->pkey.n_len = 0;
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return (srv);
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}
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/*
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* __rpc_get_time_offset()
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*
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* This function uses a nis_server structure to contact the a remote
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* machine (as named in that structure) and returns the offset in time
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* between that machine and this one. This offset is returned in seconds
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* and may be positive or negative.
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*
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* The first time through, a lot of fiddling is done with the netconfig
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* stuff to find a suitable transport. The function is very aggressive
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* about choosing UDP or at worst TCP if it can. This is because
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* those transports support both the RCPBIND call and the internet
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* time service.
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*
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* Once through, *uaddr is set to the universal address of
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* the machine and *netid is set to the local netid for the transport
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* that uaddr goes with. On the second call, the netconfig stuff
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* is skipped and the uaddr/netid pair are used to fetch the netconfig
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* structure and to then contact the machine for the time.
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*
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* td = "server" - "client"
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*/
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int
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__rpc_get_time_offset(td, srv, thost, uaddr, netid)
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struct timeval *td; /* Time difference */
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nis_server *srv; /* NIS Server description */
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char *thost; /* if no server, this is the timehost */
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char **uaddr; /* known universal address */
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struct sockaddr_in *netid; /* known network identifier */
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{
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CLIENT *clnt; /* Client handle */
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endpoint *ep, /* useful endpoints */
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*useep = NULL; /* endpoint of xp */
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char *useua = NULL; /* uaddr of selected xp */
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int epl, i; /* counters */
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enum clnt_stat status; /* result of clnt_call */
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u_long thetime, delta;
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int needfree = 0;
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struct timeval tv;
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int time_valid;
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int udp_ep = -1, tcp_ep = -1;
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int a1, a2, a3, a4;
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char ut[64], ipuaddr[64];
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endpoint teps[32];
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nis_server tsrv;
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void (*oldsig)() = NULL; /* old alarm handler */
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struct sockaddr_in sin;
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int s = RPC_ANYSOCK, len;
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int type = 0;
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td->tv_sec = 0;
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td->tv_usec = 0;
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/*
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* First check to see if we need to find and address for this
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* server.
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*/
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if (*uaddr == NULL) {
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if ((srv != NULL) && (thost != NULL)) {
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msg("both timehost and srv pointer used!");
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return (0);
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}
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if (! srv) {
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srv = get_server(netid, thost, &tsrv, teps, 32);
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if (srv == NULL) {
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msg("unable to contruct server data.");
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return (0);
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}
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needfree = 1; /* need to free data in endpoints */
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}
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ep = srv->ep.ep_val;
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epl = srv->ep.ep_len;
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/* Identify the TCP and UDP endpoints */
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for (i = 0;
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(i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) {
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if (strcasecmp(ep[i].proto, "udp") == 0)
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udp_ep = i;
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if (strcasecmp(ep[i].proto, "tcp") == 0)
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tcp_ep = i;
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}
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/* Check to see if it is UDP or TCP */
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if (tcp_ep > -1) {
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useep = &ep[tcp_ep];
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useua = ep[tcp_ep].uaddr;
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type = SOCK_STREAM;
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} else if (udp_ep > -1) {
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useep = &ep[udp_ep];
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useua = ep[udp_ep].uaddr;
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type = SOCK_DGRAM;
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}
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if (useep == NULL) {
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msg("no acceptable transport endpoints.");
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if (needfree)
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free_eps(teps, tsrv.ep.ep_len);
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return (0);
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}
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}
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/*
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* Create a sockaddr from the uaddr.
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*/
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if (*uaddr != NULL)
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useua = *uaddr;
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/* Fixup test for NIS+ */
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sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
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sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4);
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useua = &ipuaddr[0];
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bzero((char *)&sin, sizeof(sin));
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if (uaddr_to_sockaddr(useua, &sin)) {
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msg("unable to translate uaddr to sockaddr.");
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if (needfree)
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free_eps(teps, tsrv.ep.ep_len);
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return (0);
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}
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/*
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* Create the client handle to rpcbind. Note we always try
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* version 3 since that is the earliest version that supports
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* the RPCB_GETTIME call. Also it is the version that comes
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* standard with SVR4. Since most everyone supports TCP/IP
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* we could consider trying the rtime call first.
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*/
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clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0);
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if (clnt == NULL) {
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msg("unable to create client handle to rpcbind.");
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if (needfree)
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free_eps(teps, tsrv.ep.ep_len);
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return (0);
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}
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tv.tv_sec = 5;
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tv.tv_usec = 0;
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time_valid = 0;
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status = clnt_call(clnt, RPCBPROC_GETTIME, xdr_void, NULL,
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xdr_u_long, (char *)&thetime, tv);
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/*
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* The only error we check for is anything but success. In
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* fact we could have seen PROGMISMATCH if talking to a 4.1
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* machine (pmap v2) or TIMEDOUT if the net was busy.
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*/
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if (status == RPC_SUCCESS)
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time_valid = 1;
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else {
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int save;
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/* Blow away possible stale CLNT handle. */
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if (clnt != NULL) {
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clnt_destroy(clnt);
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clnt = NULL;
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}
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/*
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* Convert PMAP address into timeservice address
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* We take advantage of the fact that we "know" what
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* the universal address looks like for inet transports.
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*
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* We also know that the internet timeservice is always
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* listening on port 37.
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*/
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sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
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sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4);
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if (uaddr_to_sockaddr(ut, &sin)) {
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msg("cannot convert timeservice uaddr to sockaddr.");
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goto error;
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}
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s = socket(AF_INET, type, 0);
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if (s == -1) {
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msg("unable to open fd to network.");
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goto error;
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}
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/*
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* Now depending on whether or not we're talking to
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* UDP we set a timeout or not.
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*/
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if (type == SOCK_DGRAM) {
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struct timeval timeout = { 20, 0 };
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struct sockaddr_in from;
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fd_set readfds;
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int res;
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if (sendto(s, &thetime, sizeof(thetime), 0,
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(struct sockaddr *)&sin, sizeof(sin)) == -1) {
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msg("udp : sendto failed.");
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goto error;
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}
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do {
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FD_ZERO(&readfds);
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FD_SET(s, &readfds);
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res = select(_rpc_dtablesize(), &readfds,
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(fd_set *)NULL, (fd_set *)NULL, &timeout);
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} while (res < 0 && errno == EINTR);
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if (res <= 0)
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goto error;
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len = sizeof(from);
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res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0,
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(struct sockaddr *)&from, &len);
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if (res == -1) {
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msg("recvfrom failed on udp transport.");
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goto error;
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}
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time_valid = 1;
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} else {
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int res;
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oldsig = (void (*)())signal(SIGALRM, alarm_hndler);
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saw_alarm = 0; /* global tracking the alarm */
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alarm(20); /* only wait 20 seconds */
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res = connect(s, (struct sockaddr *)&sin, sizeof(sin));
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if (res == -1) {
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msg("failed to connect to tcp endpoint.");
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goto error;
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}
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if (saw_alarm) {
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msg("alarm caught it, must be unreachable.");
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goto error;
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}
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res = read(s, (char *)&thetime, sizeof(thetime));
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if (res != sizeof(thetime)) {
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if (saw_alarm)
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msg("timed out TCP call.");
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else
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msg("wrong size of results returned");
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goto error;
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}
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time_valid = 1;
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}
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save = errno;
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(void) close(s);
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errno = save;
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s = RPC_ANYSOCK;
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if (time_valid) {
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thetime = ntohl(thetime);
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thetime = thetime - TOFFSET; /* adjust to UNIX time */
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} else
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thetime = 0;
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}
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gettimeofday(&tv, 0);
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error:
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/*
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* clean up our allocated data structures.
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*/
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if (s != RPC_ANYSOCK)
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(void) close(s);
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if (clnt != NULL)
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clnt_destroy(clnt);
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alarm(0); /* reset that alarm if its outstanding */
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if (oldsig) {
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signal(SIGALRM, oldsig);
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}
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/*
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* note, don't free uaddr strings until after we've made a
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* copy of them.
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*/
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if (time_valid) {
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if (*uaddr == NULL)
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*uaddr = strdup(useua);
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/* Round to the nearest second */
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tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0;
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delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec :
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tv.tv_sec - thetime;
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td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta;
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td->tv_usec = 0;
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} else {
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msg("unable to get the server's time.");
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}
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if (needfree)
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free_eps(teps, tsrv.ep.ep_len);
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return (time_valid);
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}
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