text: #include <net-snmp/net-snmp-config.h>
  
  #include <net-snmp/library/snmpAAL5PVCDomain.h>
  
  #include <stdio.h>
  #include <sys/types.h>
  #include <ctype.h>
  #include <errno.h>
  
  #if HAVE_STRING_H
  #include <string.h>
  #else
  #include <strings.h>
  #endif
  #if HAVE_STDLIB_H
  #include <stdlib.h>
  #endif
  #if HAVE_UNISTD_H
  #include <unistd.h>
  #endif
  #if HAVE_SYS_SOCKET_H
  #include <sys/socket.h>
  #endif
  #include <atm.h>
  
  #if HAVE_DMALLOC_H
  #include <dmalloc.h>
  #endif
  
  #include <net-snmp/types.h>
  #include <net-snmp/output_api.h>
  #include <net-snmp/config_api.h>
  
  #include <net-snmp/library/snmp_transport.h>
  #include <net-snmp/library/tools.h>
  
  
  oid netsnmp_AAL5PVCDomain[10] = { NETSNMP_ENTERPRISE_MIB, 3, 3, 3 };
  static netsnmp_tdomain aal5pvcDomain;
  
  
  /*
   * Return a string representing the address in data, or else the "far end"
   * address if data is NULL.  
   */
  
  static char *
  netsnmp_aal5pvc_fmtaddr(netsnmp_transport *t, const void *data, int len)
  {
      const struct sockaddr_atmpvc *to = NULL;
  
      if (data != NULL && len == sizeof(struct sockaddr_atmpvc)) {
          to = (const struct sockaddr_atmpvc *) data;
      } else if (t != NULL && t->data != NULL &&
                 t->data_length == sizeof(struct sockaddr_atmpvc)) {
          to = (const struct sockaddr_atmpvc *) t->data;
      }
      if (to == NULL) {
          return strdup("AAL5 PVC: unknown");
      } else {
          char *tmp;
  
          if (asprintf(&tmp, "AAL5 PVC: %hd.%hd.%d", to->sap_addr.itf,
  		     to->sap_addr.vpi, to->sap_addr.vci) < 0)
              tmp = NULL;
          return tmp;
      }
  }
  
  static void
  netsnmp_aal5pvc_get_taddr(netsnmp_transport *t, void **addr, size_t *addr_len)
  {
      struct sockaddr_atmpvc *sa = t->remote;
      unsigned char *p;
  
      *addr_len = 8;
      if (!(*addr = malloc(*addr_len)))
          return;
      p = *addr;
      p[0] = sa->sap_addr.itf >> 8;
      p[1] = sa->sap_addr.itf >> 0;
      p[2] = sa->sap_addr.vpi >> 8;
      p[3] = sa->sap_addr.vpi >> 0;
      p[4] = sa->sap_addr.vci >> 24;
      p[5] = sa->sap_addr.vci >> 16;
      p[6] = sa->sap_addr.vci >> 8;
      p[7] = sa->sap_addr.vci >> 0;
  }
  
  /*
   * You can write something into opaque that will subsequently get passed back 
   * to your send function if you like.  For instance, you might want to
   * remember where a PDU came from, so that you can send a reply there...  
   */
  
  static int
  netsnmp_aal5pvc_recv(netsnmp_transport *t, void *buf, int size,
  		     void **opaque, int *olength)
  {
      int rc = -1;
  
      if (t != NULL && t->sock >= 0) {
  	while (rc < 0) {
  	    rc = recvfrom(t->sock, buf, size, 0, NULL, NULL);
  	    if (rc < 0 && errno != EINTR) {
  		break;
  	    }
  	}
  
          if (rc >= 0) {
              DEBUGIF("netsnmp_aal5pvc") {
                  char *str = netsnmp_aal5pvc_fmtaddr(t, NULL, 0);
                  DEBUGMSGTL(("netsnmp_aal5pvc",
                              "recv on fd %d got %d bytes (from %s)\n", t->sock,
                              rc, str));
                  free(str);
              }
          } else {
              DEBUGMSGTL(("netsnmp_aal5pvc", "recv on fd %d err %d (\"%s\")\n", 
  			t->sock, errno, strerror(errno)));
          }
          *opaque = NULL;
          *olength = 0;
      }
      return rc;
  }
  
  
  
  static int
  netsnmp_aal5pvc_send(netsnmp_transport *t, const void *buf, int size,
                       void **opaque, int *olength)
  {
      int rc = -1;
      const struct sockaddr *to = NULL;
  
      if (opaque != NULL && *opaque != NULL &&
          *olength == sizeof(struct sockaddr_atmpvc)) {
          to = (const struct sockaddr *) (*opaque);
      } else if (t != NULL && t->data != NULL &&
                 t->data_length == sizeof(struct sockaddr_atmpvc)) {
          to = (const struct sockaddr *) (t->data);
      }
  
      if (to != NULL && t != NULL && t->sock >= 0) {
          DEBUGIF("netsnmp_aal5pvc") {
              char *str = netsnmp_aal5pvc_fmtaddr(NULL, to,
                                                  sizeof(struct sockaddr_atmpvc));
              DEBUGMSGTL(("netsnmp_aal5pvc",
                          "send %d bytes from %p to %s on fd %d\n",
                          size, buf, str, t->sock));
              free(str);
          }
  	while (rc < 0) {
  	    rc = sendto(t->sock, buf, size, 0, NULL, 0);
  	    if (rc < 0 && errno != EINTR) {
  		break;
  	    }
  	}
      }
      return rc;
  }
  
  
  
  static int
  netsnmp_aal5pvc_close(netsnmp_transport *t)
  {
      int rc = -1;
  
      if (t->sock >= 0) {
          DEBUGMSGTL(("netsnmp_aal5pvc", "close fd %d\n", t->sock));
  #ifndef HAVE_CLOSESOCKET
          rc = close(t->sock);
  #else
          rc = closesocket(t->sock);
  #endif
          t->sock = -1;
      }
      return rc;
  }
  
  
  
  /*
   * Open an AAL5 PVC transport for SNMP.  Local is TRUE if addr is the local 
   * NSAP to bind to (i.e. this is a server-type session); otherwise addr is 
   * the remote NSAP to send things to.  
   */
  
  netsnmp_transport *
  netsnmp_aal5pvc_transport(const struct sockaddr_atmpvc *addr, int local)
  {
      netsnmp_transport *t = NULL;
  
  #ifdef NETSNMP_NO_LISTEN_SUPPORT
      if (local)
          return NULL;
  #endif /* NETSNMP_NO_LISTEN_SUPPORT */
  
      if (addr == NULL || addr->sap_family != AF_ATMPVC) {
          return NULL;
      }
  
      t = SNMP_MALLOC_TYPEDEF(netsnmp_transport);
      if (t == NULL) {
          return NULL;
      }
  
      DEBUGIF("netsnmp_aal5pvc") {
          char *str = netsnmp_aal5pvc_fmtaddr(NULL, addr,
                                              sizeof(struct sockaddr_atmpvc));
          DEBUGMSGTL(("netsnmp_aal5pvc", "open %s %s\n",
                      local ? "local" : "remote", str));
          free(str);
      }
  
      t->domain = netsnmp_AAL5PVCDomain;
      t->domain_length =
          sizeof(netsnmp_AAL5PVCDomain) / sizeof(netsnmp_AAL5PVCDomain[0]);
  
      t->sock = socket(PF_ATMPVC, SOCK_DGRAM, 0);
      if (t->sock < 0) {
          DEBUGMSGTL(("netsnmp_aal5pvc","socket failed (%s)\n",strerror(errno)));
          netsnmp_transport_free(t);
          return NULL;
      }
      DEBUGMSGTL(("netsnmp_aal5pvc", "fd %d opened\n", t->sock));
  
      {
          /*
           * Set up the QOS parameters.
           */
  
          struct atm_qos qos = { };
          qos.aal = ATM_AAL5;
          qos.rxtp.traffic_class = ATM_UBR;
          qos.rxtp.max_sdu = SNMP_MAX_LEN;    /*  Hmm -- this is a bit small?  */
          qos.txtp = qos.rxtp;
  
          if (setsockopt(t->sock, SOL_ATM, SO_ATMQOS, &qos, sizeof(qos)) < 0) {
              DEBUGMSGTL(("netsnmp_aal5pvc", "setsockopt failed (%s)\n",
                          strerror(errno)));
              netsnmp_aal5pvc_close(t);
              netsnmp_transport_free(t);
              return NULL;
          }
      }
  
      if (local) {
  #ifndef NETSNMP_NO_LISTEN_SUPPORT
          t->local_length = sizeof(*addr);
          t->local = netsnmp_memdup(addr, sizeof(*addr));
          if (t->local == NULL) {
              netsnmp_transport_free(t);
              return NULL;
          }
  
          if (bind(t->sock, (const struct sockaddr *)addr,
                   sizeof(struct sockaddr_atmpvc)) < 0) {
              DEBUGMSGTL(("netsnmp_aal5pvc", "bind failed (%s)\n",
                          strerror(errno)));
              netsnmp_aal5pvc_close(t);
              netsnmp_transport_free(t);
              return NULL;
          }
  #else /* NETSNMP_NO_LISTEN_SUPPORT */
          return NULL;
  #endif /* NETSNMP_NO_LISTEN_SUPPORT */
      } else {
          t->remote_length = sizeof(*addr);
          t->remote = netsnmp_memdup(addr, sizeof(*addr));
          if (t->remote == NULL) {
              netsnmp_transport_free(t);
              return NULL;
          }
  
          if (connect(t->sock, (const struct sockaddr *)addr,
                      sizeof(struct sockaddr_atmpvc)) < 0) {
              DEBUGMSGTL(("netsnmp_aal5pvc", "connect failed (%s)\n",
                          strerror(errno)));
              netsnmp_aal5pvc_close(t);
              netsnmp_transport_free(t);
              return NULL;
          }
      }
  
      t->data = malloc(sizeof(struct sockaddr_atmpvc));
      if (t->data == NULL) {
          netsnmp_transport_free(t);
          return NULL;
      }
      memcpy(t->data, addr, sizeof(struct sockaddr_atmpvc));
      t->data_length = sizeof(struct sockaddr_atmpvc);
  
      /*
       * 16-bit length field in the trailer, no headers.  
       */
  
      t->msgMaxSize = 0xffff;
      t->f_recv     = netsnmp_aal5pvc_recv;
      t->f_send     = netsnmp_aal5pvc_send;
      t->f_close    = netsnmp_aal5pvc_close;
      t->f_accept   = NULL;
      t->f_fmtaddr  = netsnmp_aal5pvc_fmtaddr;
      t->f_get_taddr = netsnmp_aal5pvc_get_taddr;
  
      return t;
  }
  
  
  
  netsnmp_transport *
  netsnmp_aal5pvc_create_tstring(const char *str, int local,
  			       const char *default_target)
  {
      struct sockaddr_atmpvc addr;
  
      if (str == NULL || *str == '\0')
  	str = default_target;
  
      if (str != NULL) {
          addr.sap_family = AF_ATMPVC;
  
          if (sscanf(str, "%hd.%hd.%d", &(addr.sap_addr.itf),
                     &(addr.sap_addr.vpi), &(addr.sap_addr.vci)) == 3) {
              return netsnmp_aal5pvc_transport(&addr, local);
          } else if (sscanf(str, "%hd.%d", &(addr.sap_addr.vpi),
                            &(addr.sap_addr.vci)) == 2) {
              addr.sap_addr.itf = 0;
              return netsnmp_aal5pvc_transport(&addr, local);
          } else if (sscanf(str, "%d", &(addr.sap_addr.vci)) == 1) {
              addr.sap_addr.itf = 0;
              addr.sap_addr.vpi = 0;
              return netsnmp_aal5pvc_transport(&addr, local);
          } else {
              return NULL;
          }
      } else {
          return NULL;
      }
  }
  
  static int netsnmp_aal5pvc_ostring_to_sockaddr(struct sockaddr_atmpvc *sa,
                                                 const void *o, size_t o_len)
  {
      const unsigned char *p = o;
  
      if (o_len != 8)
          return 0;
  
      memset(sa, 0, sizeof(*sa));
      sa->sap_family = AF_ATMPVC;
      sa->sap_addr.itf = (p[0] << 8) + (p[1] << 0);
      sa->sap_addr.vpi = (p[2] << 8) + (p[3] << 0);
      sa->sap_addr.vci = (p[4] << 24) + (p[5] << 16) + (p[6] << 8) + (p[7] << 0);
      return 1;
  }
  
  netsnmp_transport *
  netsnmp_aal5pvc_create_ostring(const void *o, size_t o_len, int local)
  {
      struct sockaddr_atmpvc sa;
  
      if (netsnmp_aal5pvc_ostring_to_sockaddr(&sa, o, o_len))
          return netsnmp_aal5pvc_transport(&sa, local);
      return NULL;
  }
  
  
  
  void
  netsnmp_aal5pvc_ctor(void)
  {
      aal5pvcDomain.name = netsnmp_AAL5PVCDomain;
      aal5pvcDomain.name_length = sizeof(netsnmp_AAL5PVCDomain) / sizeof(oid);
      aal5pvcDomain.prefix = (const char**)calloc(3, sizeof(char *));
      aal5pvcDomain.prefix[0] = "aal5pvc";
      aal5pvcDomain.prefix[1] = "pvc";
  
      aal5pvcDomain.f_create_from_tstring_new = netsnmp_aal5pvc_create_tstring;
      aal5pvcDomain.f_create_from_ostring     = netsnmp_aal5pvc_create_ostring;
  
      netsnmp_tdomain_register(&aal5pvcDomain);
  }
  