inet.c

一个学习SNMP项目：tmoerlan.

/*
 * lib/inet.c	This file contains an implementation of the "INET"
 *		support functions for the net-tools.
 *		(NET-3 base distribution).
 *
 * Version:	lib/inet.c 1.26 1996-03-29
 *
 * Author:	Fred N. van Kempen, <[e-mail]>
 *		Copyright 1993 MicroWalt Corporation
 *
 * Modified:
 *960113 {1.21}	Bernd Eckenfels :	rresolve cache bug.
 *960128 {1.22}	Bernd Eckenfels :	endian bug in print
 *960203 {1.23} Bernd Eckenfels :       net-features support
 *960217 {1.24} Bernd Eckenfels :	get_sname
 *960219 {1.25} Bernd Eckenfels :	extern int h_errno
 *960329 {1.26} Bernd Eckenfels :	resolve 255.255.255.255	
 *
 *		This program 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 of the License, or  (at
 *		your option) any later version.
 */
#include "config.h"

#if HAVE_AFINET
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <resolv.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include "version.h"
#include "net-support.h"
#include "pathnames.h"
#include "intl.h"

extern int h_errno;  /* some netdb.h versions don't export this */

struct addr {
  struct sockaddr_in	addr;
  char			*name;
  struct addr		*next;
};

struct service {
  int number;
  char *name;
  struct service *next;
};

static struct service *tcp_name = NULL,
		      *udp_name = NULL,
		      *raw_name = NULL;


static struct addr *INET_nn = NULL;	/* addr-to-name cache		*/


static int
INET_resolve(char *name, struct sockaddr_in *sin)
{
  struct hostent *hp;
  struct netent *np;

  /* Grmpf. -FvK */
  sin->sin_family = AF_INET;
  sin->sin_port = 0;

  /* Default is special, meaning 0.0.0.0. */
  if (!strcmp(name, "default")) {
	sin->sin_addr.s_addr = INADDR_ANY;
	return(1);
  }

  /* Look to see if it's a dotted quad. */
  if (inet_aton(name, &sin->sin_addr)) {
    return 0;
  }

  /* Try the NETWORKS database to see if this is a known network. */
  if ((np = getnetbyname(name)) != (struct netent *)NULL) {
    sin->sin_addr.s_addr = htonl(np->n_net);
    strcpy(name, np->n_name);
    return 1;
  }

#ifdef DEBUG
  res_init();
  _res.options |= RES_DEBUG;
#endif

  if ((hp = gethostbyname(name)) == (struct hostent *)NULL) {
    errno = h_errno;
    return -1;
  }
  memcpy((char *) &sin->sin_addr, (char *) hp->h_addr_list[0], hp->h_length);
  strcpy(name, hp->h_name);
  return 0;
}


static int
INET_rresolve(char *name, struct sockaddr_in *sin, int numeric)
{
  struct hostent *ent;
  struct netent *np;
  struct addr *pn;
  unsigned long ad, host_ad;

  /* Grmpf. -FvK */
  if (sin->sin_family != AF_INET) {
#ifdef DEBUG
	fprintf(stderr, _("rresolve: unsupport address family %d !\n"), sin->sin_family);
#endif
	errno = EAFNOSUPPORT;
	return(-1);
  }

  ad = (unsigned long) sin->sin_addr.s_addr;
  if (ad == INADDR_ANY) {
	if ((numeric & 0x7FFF) == 0) {
		if (numeric & 0x8000) strcpy(name, "default");
		  else strcpy(name, "*");
		return(0);
	}
  }
  if (numeric & 0x7FFF) {
	strcpy(name,inet_ntoa (sin->sin_addr));
	return(0);
  }

#if 0
  INET_nn = NULL;
#endif
  pn = INET_nn;
  while (pn != NULL) {
	if (pn->addr.sin_addr.s_addr == ad) {
		strcpy(name, pn->name);
		return(0);
	}
	pn = pn->next;
  }

  host_ad = ntohl(ad);
  np = NULL;
  ent = NULL;
  if ((host_ad & 0xFF) != 0)  {
	ent = gethostbyaddr((char *) &ad, 4, AF_INET);
	if (ent != NULL)
		strcpy(name, ent->h_name);
  } else {
	np = getnetbyaddr(host_ad, AF_INET);
	if (np != NULL) {
		strcpy(name, np->n_name);
	}
  }
  if ((ent == NULL) && (np == NULL)) {
	strcpy(name,inet_ntoa (sin->sin_addr));
  }
  pn = (struct addr *)malloc(sizeof(struct addr));
  pn->addr = *sin;
  pn->next = INET_nn;
  pn->name = (char *) malloc(strlen(name) + 1);
  strcpy(pn->name, name);
  INET_nn = pn;

  return(0);
}


static void
INET_reserror(char *text)
{
  herror(text);
}


/* Display an Internet socket address. */
static char *
INET_print(unsigned char *ptr)
{
  return(inet_ntoa((*(struct in_addr *) ptr)));
}


/* Display an Internet socket address. */
static char *
INET_sprint(struct sockaddr *sap, int numeric)
{
  static char buff[128];

  if (sap->sa_family == 0xFFFF || sap->sa_family == 0)
	return strncpy (buff, _("[NONE SET]"), sizeof(buff));
  if (INET_rresolve(buff, (struct sockaddr_in *) sap, numeric) != 0)
							return(NULL);
  return(buff);
}


static int
INET_getsock(char *bufp, struct sockaddr *sap)
{
  char *sp = bufp,*bp;
  unsigned int i;
  unsigned val;
  struct sockaddr_in *sin;
  
  sin             = (struct sockaddr_in *) sap;
  sin->sin_family = AF_INET;
  sin->sin_port   = 0;

  val = 0;
  bp=(char *)&val;
  for (i = 0; i < sizeof(sin->sin_addr.s_addr); i++) {
	*sp = toupper(*sp);
	
	if ((*sp >= 'A') && (*sp <= 'F')) 
		bp[i] |= (int) (*sp - 'A') + 10;
	else if ((*sp >= '0') && (*sp <= '9'))
		bp[i] |= (int) (*sp - '0');
	else
		return(-1);

	bp[i] <<= 4;
	sp++;
	*sp = toupper(*sp);
	
	if ((*sp >= 'A') && (*sp <= 'F')) 
		bp[i] |= (int) (*sp - 'A') + 10;
	else if ((*sp >= '0') && (*sp <= '9'))
		bp[i] |= (int) (*sp - '0');
	else
		return(-1);
	
	sp++;
    }
    sin->sin_addr.s_addr = htonl (val);

    return(sp-bufp);
}

static int
INET_input(int type, char *bufp, struct sockaddr *sap)
{
  switch(type) {
  	case 1:
		return(INET_getsock(bufp,sap));
	default:
		return(INET_resolve(bufp, (struct sockaddr_in *) sap));
  }
}

static int INET_getnetmask(char *adr, struct sockaddr *m, char *name)
{ 
	struct sockaddr_in *mask = (struct sockaddr_in *)m; 
	char *slash, *end; 
	int prefix; 

	if ((slash = strchr(adr, '/')) == NULL) 
		return 0; 
		
	*slash++ = '\0';
	prefix = strtoul(slash,&end,0);
	if (*end != '\0') 
		return -1; 

	if (name) {
		sprintf(name, "/%d", prefix); 
	}
		
	mask->sin_family = AF_INET; 
    mask->sin_addr.s_addr = htonl(~(0xffffffffU >> prefix)); 
	return 1;
} 


struct aftype inet_aftype = {
  "inet",	NULL, /*"DARPA Internet",*/	AF_INET,	sizeof(unsigned long),
  INET_print,	INET_sprint,		INET_input,	INET_reserror,	
  NULL/*INET_rprint*/,	NULL/*INET_rinput*/,
  INET_getnetmask 
};

#endif	/* HAVE_AFINET || HAVE_AFINET6 */

#if HAVE_AFINET || HAVE_AFINET6

static void
add2list(struct service **namebase, struct service *item) 
{
  if (*namebase == NULL) {
	*namebase = item;
	item->next = NULL;
  } else {
	item->next = *namebase;
	*namebase = item;
  } 
}


static struct service *
searchlist(struct service *servicebase, int number)
{
  struct service *item;

  for(item = servicebase; item != NULL; item = item->next) {
	if (item->number == number) return(item);
  }
  return(NULL);
}


static int
read_services(void)
{
  struct servent *se;
  struct service *item;

  setservent(1);
  while((se=getservent())) {
	/* Allocate a service entry. */
	item = (struct service *) malloc(sizeof(struct service));
	if (item == NULL) perror("netstat"); 
	item->name = strdup(se->s_name);
	item->number = se->s_port;

	/* Fill it in. */
	if (! strcmp(se->s_proto, "tcp")) {
		add2list(&tcp_name,item);
	} else if (! strcmp(se->s_proto, "udp")) {
		add2list(&udp_name,item);
	} else if (! strcmp(se->s_proto, "raw")) {
		add2list(&raw_name,item);
	}
  }
  endservent();
  return(0);
}


char *
get_sname(int socknumber, char *proto, int numeric)
{
  static char buffer[64], init=0;
  struct service *item;

  if (socknumber == 0) return("*");
  if (numeric) {
	sprintf(buffer, "%d", ntohs(socknumber));
	return(buffer);
  }
  if (!init) {
  	(void)read_services();
  	init=1;
  }
  buffer[0]='\0';
  if (! strcmp(proto, "tcp")) {
	if ((item = searchlist(tcp_name, socknumber)) != NULL)
		sprintf(buffer, "%s", item->name);
  } else if (! strcmp(proto, "udp")) {
	if ((item = searchlist(udp_name, socknumber)) != NULL)
		sprintf(buffer, "%s", item->name);
  } else if (! strcmp(proto, "raw")) {
	if ((item = searchlist(raw_name, socknumber)) != NULL)
		sprintf(buffer, "%s", item->name);

  }
  if (!buffer[0])
  	sprintf(buffer, "%d", ntohs(socknumber));
  return(buffer);
}

#endif	/* HAVE_AFINET || HAVE_AFINET6 */