snmplib/snmpTCPIPv6Domain.c

#include <net-snmp/net-snmp-config.h>

#include <stdio.h>
#include <sys/types.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
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if HAVE_NETDB_H
#include <netdb.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif

#include <net-snmp/types.h>	
#include <net-snmp/output_api.h>
#include <net-snmp/config_api.h>

#include <net-snmp/snmp_transport.h>
#include <net-snmp/snmpUDPIPv6Domain.h>
#include <net-snmp/snmpTCPIPv6Domain.h>

const oid ucdSnmpTCPIPv6Domain[9] = { UCDAVIS_MIB, 251, 5 };
static snmp_tdomain tcp6Domain;

/*  Return a string representing the address in data, or else the "far end"
    address if data is NULL.  */

char	       *snmp_tcp6_fmtaddr	(snmp_transport *t,
					 void *data, int len)
{
  struct sockaddr_in6 *to = NULL;

  DEBUGMSGTL(("snmp_tcp6_fmtaddr", "t = %p, data = %p, len = %d\n", t, data, len));
  if (data != NULL && len == sizeof(struct sockaddr_in6)) {
    to = (struct sockaddr_in6 *)data;
  } else if (t != NULL && t->data != NULL) {
    to = (struct sockaddr_in6 *)t->data;
  }
  if (to == NULL) {
    return strdup("TCP/IPv6: unknown");
  } else {
    char addr[INET6_ADDRSTRLEN];
    char tmp[INET6_ADDRSTRLEN + 8];
    
    sprintf(tmp, "[%s]:%hd", inet_ntop(AF_INET6, (void *)&(to->sin6_addr),
				 addr, INET6_ADDRSTRLEN), ntohs(to->sin6_port));
    return strdup(tmp);
  }
}



/*  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...  */

int		snmp_tcp6_recv	(snmp_transport *t, void *buf, int size,
				 void **opaque, int *olength) 
{
  int rc = -1;

  if (t != NULL && t->sock >= 0) {
    rc = recv(t->sock, buf, size, 0);
    DEBUGMSGTL(("snmp_tcp6_recv", "recv fd %d got %d bytes\n", t->sock, rc));
  } else {
    return -1;
  }

  if (opaque != NULL && olength != NULL) {
    if (t->data_length > 0) {
      if ((*opaque = malloc(t->data_length)) != NULL) {
	memcpy(*opaque, t->data, t->data_length);
	*olength = t->data_length;
      } else {
	*olength = 0;
      }
    } else {
      *opaque  = NULL;
      *olength = 0;
    }
  }

  return rc;
}



int		snmp_tcp6_send	(snmp_transport *t, void *buf, int size,
				 void **opaque, int *olength)
{
  int rc = 0;

  if (t != NULL && t->sock >= 0) {
    rc = send(t->sock, buf, size, 0);
  } else {
    return -1;
  }
  return rc;
}



int		snmp_tcp6_close	(snmp_transport *t)
{
  int rc = 0;
  if (t != NULL && t->sock >= 0) {
    DEBUGMSGTL(("snmp_tcp6_close", "close fd %d\n", t->sock));
#ifndef HAVE_CLOSESOCKET
    rc = close(t->sock);
#else
    rc = closesocket(t->sock);
#endif
    t->sock = -1;
    return rc;
  } else {
    return -1;
  }
}



int		snmp_tcp6_accept	(snmp_transport *t)
{
  struct sockaddr_in6 *farend = NULL;
  int newsock = -1, farendlen = sizeof(struct sockaddr_in6), sockflags = 0;
  char *string = NULL;

  farend = (struct sockaddr_in6 *)malloc(sizeof(struct sockaddr_in6));

  if (farend == NULL) {
    /*  Indicate that the acceptance of this socket failed.  */
    DEBUGMSGTL(("snmp_tcp6_accept", "malloc failed\n"));
    return -1;
  }

  if (t != NULL && t->sock >= 0) {
    newsock = accept(t->sock, (struct sockaddr *)farend, &farendlen);

    if (newsock < 0) {
      DEBUGMSGTL(("snmp_tcp6_accept", "accept failed\n"));
      free(farend);
      return newsock;
    }

    if (t->data != NULL) {
      free(t->data);
    }

    t->data = farend;
    t->data_length = farendlen;
    string = snmp_tcp6_fmtaddr(NULL, farend, farendlen);
    DEBUGMSGTL(("snmp_tcp6_accept", "accept succeeded (from %s)\n", string));
    free(string);

    /*  Try to make the new socket blocking.  */

#ifdef WIN32
    ioctlsocket(newsock, FIONBIO, &sockflags);
#else
    if ((sockflags = fcntl(newsock, F_GETFL, 0)) >= 0) {
      fcntl(newsock, F_SETFL, (sockflags & ~O_NONBLOCK));
    } else {
      DEBUGMSGTL(("snmp_tcp6_accept", "couldn't f_getfl of fd %d\n", newsock));
    }
#endif

    return newsock;
  } else {
    free(farend);
    return -1;
  }
}



/*  Open a TCP/IPv6-based transport for SNMP.  Local is TRUE if addr is the
    local address to bind to (i.e. this is a server-type session); otherwise
    addr is the remote address to send things to.  */

snmp_transport		*snmp_tcp6_transport	(struct sockaddr_in6 *addr,
						 int local)
{
  snmp_transport *t = NULL;
  int rc = 0;
  char *string = NULL;

  if (addr == NULL || addr->sin6_family != AF_INET6) {
    return NULL;
  }

  t = (snmp_transport *)malloc(sizeof(snmp_transport));
  if (t == NULL) {
    return NULL;
  }
  memset(t, 0, sizeof(snmp_transport));

  string = snmp_tcp6_fmtaddr(NULL, (void *)addr, sizeof(struct sockaddr_in6));
  DEBUGMSGTL(("snmp_tcp6", "open %s %s\n", local?"local":"remote", string));
  free(string);

  memset(t, 0, sizeof(snmp_transport));

  t->data = malloc(sizeof(struct sockaddr_in6));
  if (t->data == NULL) {
    snmp_transport_free(t);
    return NULL;
  }
  t->data_length = sizeof(struct sockaddr_in6);
  memcpy(t->data, addr, sizeof(struct sockaddr_in6));

  t->domain = ucdSnmpTCPIPv6Domain;
  t->domain_length = sizeof(ucdSnmpTCPIPv6Domain)/sizeof(oid);

  t->sock = socket(PF_INET6, SOCK_STREAM, 0);
  if (t->sock < 0) {
    snmp_transport_free(t);
    return NULL;
  }

  t->flags = SNMP_TRANSPORT_FLAG_STREAM;

  if (local) {
    int sockflags = 0, opt = 1;

    /*  This session is inteneded as a server, so we must bind on to the given
	IP address, which may include an interface address, or could be
	INADDR_ANY, but certainly includes a port number.  */
    
    t->flags |= SNMP_TRANSPORT_FLAG_LISTEN;
    t->local = malloc(18);
    if (t->local == NULL) {
      snmp_tcp6_close(t);
      snmp_transport_free(t);
      return NULL;
    }
    memcpy(t->local, addr->sin6_addr.s6_addr, 16);
    t->local[16] = (addr->sin6_port & 0xff00) >> 8;
    t->local[17] = (addr->sin6_port & 0x00ff) >> 0;
    t->local_length = 18;

    /*  We should set SO_REUSEADDR too.  */
    
    setsockopt(t->sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

    rc = bind(t->sock, (struct sockaddr *)addr, sizeof(struct sockaddr_in6));
    if (rc != 0) {
      snmp_tcp6_close(t);
      snmp_transport_free(t);
      return NULL;
    }

    /*  Since we are going to be letting select() tell us when connections are 
	ready to be accept()ed, we need to make the socket n0n-blocking to
	avoid the race condition described in W. R. Stevens, ``Unix Network
	Programming Volume I Second Edition'', pp. 422--4, which could
	otherwise wedge the agent.  */

#ifdef WIN32
    opt = 1;
    ioctlsocket(t->sock, FIONBIO, &opt);
#else
    sockflags = fcntl(t->sock, F_GETFL, 0);
    fcntl(t->sock, F_SETFL, sockflags | O_NONBLOCK);
#endif

    /*  Now sit here and wait for connections to arrive.  */

    rc = listen(t->sock, SNMP_STREAM_QUEUE_LEN);
    if (rc != 0) {
      snmp_tcp6_close(t);
      snmp_transport_free(t);
      return NULL;
    }
  } else {
    t->remote = malloc(18);
    if (t->remote == NULL) {
      snmp_tcp6_close(t);
      snmp_transport_free(t);
      return NULL;
    }
    memcpy(t->remote, addr->sin6_addr.s6_addr, 16);
    t->remote[16] = (addr->sin6_port & 0xff00) >> 8;
    t->remote[17] = (addr->sin6_port & 0x00ff) >> 0;
    t->remote_length = 18;

    /*  This is a client-type session, so attempt to connect to the far end.
	We don't go non-blocking here because it's not obvious what you'd then
	do if you tried to do snmp_sends before the connection had completed.
	So this can block.  */

    rc = connect(t->sock, (struct sockaddr *)addr,sizeof(struct sockaddr_in6));

    DEBUGMSGTL(("snmp_tcp6", "connect returns %d\n", rc));

    if (rc < 0) {
      snmp_tcp6_close(t);
      snmp_transport_free(t);
      return NULL;
    }
  }

  /*  Message size is not limited by this transport (hence msgMaxSize
      is equal to the maximum legal size of an SNMP message).  */

  t->msgMaxSize  = 0x7fffffff;
  t->f_recv      = snmp_tcp6_recv;
  t->f_send      = snmp_tcp6_send;
  t->f_close     = snmp_tcp6_close;
  t->f_accept    = snmp_tcp6_accept;
  t->f_fmtaddr   = snmp_tcp6_fmtaddr;

  return t;
}



snmp_transport	*snmp_tcp6_create_tstring       (const char *string, int local)
{
  struct sockaddr_in6 addr;

  if (snmp_sockaddr_in6(&addr, string, 0)) {
    return snmp_tcp6_transport(&addr, local);
  } else {
    return NULL;
  }
}


/*  See:

    http://www.ietf.org/internet-drafts/draft-ietf-ops-taddress-mib-01.txt

    (or newer equivalent) for details of the TC which we are using for
    the mapping here.  */

snmp_transport	*snmp_tcp6_create_ostring	(const u_char *o, size_t o_len,
						 int local)
{
  struct sockaddr_in6 addr;

  if (o_len == 18) {
    memset((u_char *)&addr, 0, sizeof(struct sockaddr_in6));
    addr.sin6_family = AF_INET6;
    memcpy((u_char *)&(addr.sin6_addr.s6_addr), o, 16);
    addr.sin6_port = (o[16] << 8) + o[17];
    return snmp_tcp6_transport(&addr, local);
  }
  return NULL;
}


void		snmp_tcp6_ctor			(void)
{
  tcp6Domain.name        = ucdSnmpTCPIPv6Domain;
  tcp6Domain.name_length = sizeof(ucdSnmpTCPIPv6Domain)/sizeof(oid);
  tcp6Domain.f_create_from_tstring = snmp_tcp6_create_tstring;
  tcp6Domain.f_create_from_ostring = snmp_tcp6_create_ostring;
  tcp6Domain.prefix	 = calloc(4, sizeof(char *));
  tcp6Domain.prefix[0] 	 = "tcp6";
  tcp6Domain.prefix[1] 	 = "tcpv6";
  tcp6Domain.prefix[2] 	 = "tcpipv6";

  snmp_tdomain_register(&tcp6Domain);
}