smux.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

/* SNMP support
 * Copyright (C) 1999 Kunihiro Ishiguro <[e-mail]>
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Zebra; see the file COPYING.  If not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.  
 */

#include <zebra.h>

#ifdef HAVE_SNMP

#include <asn1.h>
#include <snmp.h>
#include <snmp_impl.h>

#include "smux.h"
#include "log.h"
#include "thread.h"
#include "linklist.h"
#include "command.h"
#include "version.h"
#include "memory.h"
#include "sockunion.h"

#define min(A,B) ((A) < (B) ? (A) : (B))

enum smux_event {SMUX_SCHEDULE, SMUX_CONNECT, SMUX_READ};

void smux_event (enum smux_event, int);


/* SMUX socket. */
int smux_sock = -1;

/* SMUX subtree list. */
struct list *treelist;

/* SMUX oid. */
oid *smux_oid;
size_t smux_oid_len;

/* SMUX default oid. */
oid *smux_default_oid;
size_t smux_default_oid_len;

/* SMUX password. */
char *smux_passwd;
char *smux_default_passwd = "";

/* SMUX read threads. */
struct thread *smux_read_thread;

/* SMUX connect thrads. */
struct thread *smux_connect_thread;

/* SMUX debug flag. */
int debug_smux = 0;

/* SMUX failure count. */
int fail = 0;

/* SMUX node. */
struct cmd_node smux_node =
{
  SMUX_NODE,
  ""                            /* SMUX has no interface. */
};

void *
oid_copy (void *dest, void *src, size_t size)
{
  return memcpy (dest, src, size * sizeof (oid));
}

void
oid2in_addr (oid oid[], int len, struct in_addr *addr)
{
  int i;
  u_char *pnt;
  
  if (len == 0)
    return;

  pnt = (u_char *) addr;

  for (i = 0; i < len; i++)
    *pnt++ = oid[i];
}

void
oid_copy_addr (oid oid[], struct in_addr *addr, int len)
{
  int i;
  u_char *pnt;
  
  if (len == 0)
    return;

  pnt = (u_char *) addr;

  for (i = 0; i < len; i++)
    oid[i] = *pnt++;
}

int
oid_compare (oid *o1, int o1_len, oid *o2, int o2_len)
{
  int i;

  for (i = 0; i < min (o1_len, o2_len); i++)
    {
      if (o1[i] < o2[i])
	return -1;
      else if (o1[i] > o2[i])
	return 1;
    }
  if (o1_len < o2_len)
    return -1;
  if (o1_len > o2_len)
    return 1;

  return 0;
}

int
oid_compare_part (oid *o1, int o1_len, oid *o2, int o2_len)
{
  int i;

  for (i = 0; i < min (o1_len, o2_len); i++)
    {
      if (o1[i] < o2[i])
	return -1;
      else if (o1[i] > o2[i])
	return 1;
    }
  if (o1_len < o2_len)
    return -1;

  return 0;
}

void
smux_oid_dump (char *prefix, oid *oid, size_t oid_len)
{
  int i;
  int first = 1;
  char buf[MAX_OID_LEN * 3];

  buf[0] = '\0';

  for (i = 0; i < oid_len; i++)
    {
      sprintf (buf + strlen (buf), "%s%d", first ? "" : ".", (int) oid[i]);
      first = 0;
    }
  zlog_info ("%s: %s", prefix, buf);
}

int
smux_socket ()
{
  int ret;
#ifdef HAVE_IPV6
  struct addrinfo hints, *res0, *res;
  int gai;
#else
  struct sockaddr_in serv;
  struct servent *sp;
#endif
  int sock = 0;

#ifdef HAVE_IPV6
  memset(&hints, 0, sizeof(hints));
  hints.ai_family = PF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;
  gai = getaddrinfo(NULL, "smux", &hints, &res0);
  if (gai == EAI_SERVICE)
    {
      char servbuf[NI_MAXSERV];
      sprintf(servbuf,"%d",SMUX_PORT_DEFAULT);
      servbuf[sizeof (servbuf) - 1] = '\0';
      gai = getaddrinfo(NULL, servbuf, &hints, &res0);
    }
  if (gai)
    {
      zlog_warn("Cannot locate loopback service smux");
      return -1;
    }
  for(res=res0; res; res=res->ai_next)
    {
      if (res->ai_family != AF_INET 
#ifdef HAVE_IPV6
	  && res->ai_family != AF_INET6
#endif /* HAVE_IPV6 */
	  )
	continue;

      sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
      if (sock < 0)
	continue;
      sockopt_reuseaddr (sock);
      sockopt_reuseport (sock);
      ret = connect (sock, res->ai_addr, res->ai_addrlen);
      if (ret < 0)
	{
	  close(sock);
	  sock = -1;
	  continue;
	}
      break;
    }
  freeaddrinfo(res0);
  if (sock < 0)
    zlog_warn ("Can't connect to SNMP agent with SMUX");
#else
  sock = socket (AF_INET, SOCK_STREAM, 0);
  if (sock < 0)
    {
      zlog_warn ("Can't make socket for SNMP");
      return -1;
    }

  memset (&serv, 0, sizeof (struct sockaddr_in));
  serv.sin_family = AF_INET;
#ifdef HAVE_SIN_LEN
  serv.sin_len = sizeof (struct sockaddr_in);
#endif /* HAVE_SIN_LEN */

  sp = getservbyname ("smux", "tcp");
  if (sp != NULL) 
    serv.sin_port = sp->s_port;
  else
    serv.sin_port = htons (SMUX_PORT_DEFAULT);

  serv.sin_addr.s_addr = htonl (INADDR_LOOPBACK);

  sockopt_reuseaddr (sock);
  sockopt_reuseport (sock);

  ret = connect (sock, (struct sockaddr *) &serv, sizeof (struct sockaddr_in));
  if (ret < 0)
    {
      close (sock);
      smux_sock = -1;
      zlog_warn ("Can't connect to SNMP agent with SMUX");
      return -1;
    }
#endif
  return sock;
}

void
smux_getresp_send (oid objid[], size_t objid_len, long reqid, long errstat,
		   long errindex, u_char val_type, void *arg, size_t arg_len)
{
  int ret;
  u_char buf[BUFSIZ];
  u_char *ptr, *h1, *h1e, *h2, *h2e;
  int len, length;

  ptr = buf;
  len = BUFSIZ;
  length = len;

  if (debug_smux)
    {
      zlog_info ("SMUX GETRSP send");
      zlog_info ("SMUX GETRSP reqid: %ld", reqid);
    }

  h1 = ptr;
  /* Place holder h1 for complete sequence */
  ptr = asn_build_sequence (ptr, &len, (u_char) SMUX_GETRSP, 0);
  h1e = ptr;
 
  ptr = asn_build_int (ptr, &len,
		       (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_INTEGER),
		       &reqid, sizeof (reqid));

  if (debug_smux)
    zlog_info ("SMUX GETRSP errstat: %ld", errstat);

  ptr = asn_build_int (ptr, &len,
		       (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_INTEGER),
		       &errstat, sizeof (errstat));
  if (debug_smux)
    zlog_info ("SMUX GETRSP errindex: %ld", errindex);

  ptr = asn_build_int (ptr, &len,
		       (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_INTEGER),
		       &errindex, sizeof (errindex));

  h2 = ptr;
  /* Place holder h2 for one variable */
  ptr = asn_build_sequence (ptr, &len, 
			   (u_char)(ASN_SEQUENCE | ASN_CONSTRUCTOR),
			   0);
  h2e = ptr;

  ptr = snmp_build_var_op (ptr, objid, &objid_len, 
			   val_type, arg_len, arg, &len);

  /* Now variable size is known, fill in size */
  asn_build_sequence(h2,&length,(u_char)(ASN_SEQUENCE|ASN_CONSTRUCTOR),ptr-h2e);

  /* Fill in size of whole sequence */
  asn_build_sequence(h1,&length,(u_char)SMUX_GETRSP,ptr-h1e);

  if (debug_smux)
    zlog_info ("SMUX getresp send: %d", ptr - buf);
  
  ret = send (smux_sock, buf, (ptr - buf), 0);
}

char *
smux_var (char *ptr, int len, oid objid[], size_t *objid_len,
          size_t *var_val_len,
          u_char *var_val_type,
          void **var_value)
{
  u_char type;
  u_char val_type;
  size_t val_len;
  u_char *val;

  if (debug_smux)
    zlog_info ("SMUX var parse: len %d", len);

  /* Parse header. */
  ptr = asn_parse_header (ptr, &len, &type);
  
  if (debug_smux)
    {
      zlog_info ("SMUX var parse: type %d len %d", type, len);
      zlog_info ("SMUX var parse: type must be %d", 
		 (ASN_SEQUENCE | ASN_CONSTRUCTOR));
    }

  /* Parse var option. */
  *objid_len = MAX_OID_LEN;
  ptr = snmp_parse_var_op(ptr, objid, objid_len, &val_type, 
			  &val_len, &val, &len);

  if (var_val_len)
    *var_val_len = val_len;

  if (var_value)
    *var_value = (void*) val;

  if (var_val_type)
    *var_val_type = val_type;

  /* Requested object id length is objid_len. */
  if (debug_smux)
    smux_oid_dump ("Request OID", objid, *objid_len);

  if (debug_smux)
    zlog_info ("SMUX val_type: %d", val_type);

  /* Check request value type. */
  if (debug_smux)
  switch (val_type)
    {
    case ASN_NULL:
      /* In case of SMUX_GET or SMUX_GET_NEXT val_type is set to
         ASN_NULL. */
      zlog_info ("ASN_NULL");
      break;

    case ASN_INTEGER:
      zlog_info ("ASN_INTEGER");
      break;
    case ASN_COUNTER:
    case ASN_GAUGE:
    case ASN_TIMETICKS:
    case ASN_UINTEGER:
      zlog_info ("ASN_COUNTER");
      break;
    case ASN_COUNTER64:
      zlog_info ("ASN_COUNTER64");
      break;
    case ASN_IPADDRESS:
      zlog_info ("ASN_IPADDRESS");
      break;
    case ASN_OCTET_STR:
      zlog_info ("ASN_OCTET_STR");
      break;
    case ASN_OPAQUE:
    case ASN_NSAP:
    case ASN_OBJECT_ID:
      zlog_info ("ASN_OPAQUE");
      break;
    case SNMP_NOSUCHOBJECT:
      zlog_info ("SNMP_NOSUCHOBJECT");
      break;
    case SNMP_NOSUCHINSTANCE:
      zlog_info ("SNMP_NOSUCHINSTANCE");
      break;
    case SNMP_ENDOFMIBVIEW:
      zlog_info ("SNMP_ENDOFMIBVIEW");
      break;
    case ASN_BIT_STR:
      zlog_info ("ASN_BIT_STR");
      break;
    default:
      zlog_info ("Unknown type");
      break;
    }
  return ptr;
}

/* NOTE: all 3 functions (smux_set, smux_get & smux_getnext) are based on
   ucd-snmp smux and as such suppose, that the peer receives in the message
   only one variable. Fortunately, IBM seems to do the same in AIX. */

int
smux_set (oid *reqid, size_t *reqid_len,
          u_char val_type, void *val, size_t val_len, int action)
{
  int j;
  struct subtree *subtree;
  struct variable *v;
  int subresult;
  oid *suffix;
  int suffix_len;
  int result;
  u_char *statP = NULL;
  WriteMethod *write_method = NULL;
  struct listnode *node;

  /* Check */
  for (node = treelist->head; node; node = node->next)
    {
      subtree = node->data;
      subresult = oid_compare_part (reqid, *reqid_len,
                                    subtree->name, subtree->name_len);

      /* Subtree matched. */
      if (subresult == 0)
        {
          /* Prepare suffix. */
          suffix = reqid + subtree->name_len;
          suffix_len = *reqid_len - subtree->name_len;
          result = subresult;

          /* Check variables. */
          for (j = 0; j < subtree->variables_num; j++)
            {
              v = &subtree->variables[j];

              /* Always check suffix */
              result = oid_compare_part (suffix, suffix_len,
                                         v->name, v->namelen);

              /* This is exact match so result must be zero. */
              if (result == 0)
                {
                  if (debug_smux)
                    zlog_info ("SMUX function call index is %d", v->magic);
		  
                  statP = (*v->findVar) (v, suffix, &suffix_len, 1,
					 &val_len, &write_method);

                  if (write_method)
                    {
                      return (*write_method)(action, val, val_type, val_len,
					     statP, suffix, suffix_len, v);
                    }
                  else
                    {
                      return SNMP_ERR_READONLY;
                    }
                }

              /* If above execution is failed or oid is small (so
                 there is no further match). */
              if (result < 0)
                return SNMP_ERR_NOSUCHNAME;
            }
        }
    }
  return SNMP_ERR_NOSUCHNAME;
}

int
smux_get (oid *reqid, size_t *reqid_len, int exact,