getifaddrs.c

实现了poll/epoll/devpoll等C++封装

/* downloaded from http://ftp.uninett.no/pub/OpenBSD/src/kerberosV/src/lib/roken/getifaddrs.c */
#if !HAVE_GETIFADDRS
/*
 * Copyright (c) 2000 - 2001 Kungliga Tekniska H鰃skolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>

#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif

#ifdef HAVE_NETINET_IN6_VAR_H
#include <netinet/in6_var.h>
#endif

#ifndef max
#define max(a,b) ((a)>(b)?(a):(b))
#endif

#include "getifaddrs.h"

static int
getifaddrs2(struct ifaddrs **ifap, 
	    int af, int siocgifconf, int siocgifflags,
	    size_t ifreq_sz)
{
    int ret;
    int fd;
    size_t buf_size;
    char *buf;
    struct ifconf ifconf;
    int num, j = 0;
    char *p;
    size_t sz;
    struct sockaddr sa_zero;
    struct ifreq *ifr;

    struct ifaddrs *start,  **end = &start;

    buf = NULL;

    memset (&sa_zero, 0, sizeof(sa_zero));
    fd = socket(af, SOCK_DGRAM, 0);
    if (fd < 0)
	return -1;

    buf_size = 8192;
    for (;;) {
	buf = calloc(1, buf_size);
	if (buf == NULL) {
	    ret = ENOMEM;
	    goto error_out;
	}
	ifconf.ifc_len = buf_size;
	ifconf.ifc_buf = buf;

	/*
	 * Solaris returns EINVAL when the buffer is too small.
	 */
	if (ioctl (fd, siocgifconf, &ifconf) < 0 && errno != EINVAL) {
	    ret = errno;
	    goto error_out;
	}
	/*
	 * Can the difference between a full and a overfull buf
	 * be determined?
	 */

	if (ifconf.ifc_len < (int)buf_size)
	    break;
	free (buf);
	buf_size *= 2;
    }

    num = ifconf.ifc_len / ifreq_sz;
    j = 0;
    for (p = ifconf.ifc_buf;
	 p < ifconf.ifc_buf + ifconf.ifc_len;
	 p += sz) {
	struct ifreq ifreq;
	struct sockaddr *sa;
	size_t salen;

	ifr = (struct ifreq *)p;
	sa  = &ifr->ifr_addr;

	sz = ifreq_sz;
	salen = sizeof(struct sockaddr);
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
	salen = sa->sa_len;
	sz = max(sz, sizeof(ifr->ifr_name) + sa->sa_len);
#endif
#ifdef SA_LEN
	salen = SA_LEN(sa);
	sz = max(sz, sizeof(ifr->ifr_name) + SA_LEN(sa));
#endif
	memset (&ifreq, 0, sizeof(ifreq));
	memcpy (ifreq.ifr_name, ifr->ifr_name, sizeof(ifr->ifr_name));

	if (ioctl(fd, siocgifflags, &ifreq) < 0) {
	    ret = errno;
	    goto error_out;
	}

	*end = malloc(sizeof(**end));

	(*end)->ifa_next = NULL;
	(*end)->ifa_name = strdup(ifr->ifr_name);
	(*end)->ifa_flags = ifreq.ifr_flags;
	(*end)->ifa_addr = malloc(salen);
	memcpy((*end)->ifa_addr, sa, salen);
	(*end)->ifa_netmask = NULL;

#if 0
	/* fix these when we actually need them */
	if(ifreq.ifr_flags & IFF_BROADCAST) {
	    (*end)->ifa_broadaddr = malloc(sizeof(ifr->ifr_broadaddr));
	    memcpy((*end)->ifa_broadaddr, &ifr->ifr_broadaddr, 
		   sizeof(ifr->ifr_broadaddr));
	} else if(ifreq.ifr_flags & IFF_POINTOPOINT) {
	    (*end)->ifa_dstaddr = malloc(sizeof(ifr->ifr_dstaddr));
	    memcpy((*end)->ifa_dstaddr, &ifr->ifr_dstaddr, 
		   sizeof(ifr->ifr_dstaddr));
	} else
	    (*end)->ifa_dstaddr = NULL;
#else
	    (*end)->ifa_dstaddr = NULL;
#endif

	(*end)->ifa_data = NULL;

	end = &(*end)->ifa_next;
	
    }
    *ifap = start;
    close(fd);
    free(buf);
    return 0;
  error_out:
    close(fd);
    free(buf);
    errno = ret;
    return -1;
}

int
getifaddrs(struct ifaddrs **ifap) 
{
    int ret = -1;
    errno = ENXIO;
#if defined(AF_INET6) && defined(SIOCGIF6CONF) && defined(SIOCGIF6FLAGS)
    if (ret)
	ret = getifaddrs2 (ifap, AF_INET6, SIOCGIF6CONF, SIOCGIF6FLAGS,
			   sizeof(struct in6_ifreq));
#endif
#if defined(HAVE_IPV6) && defined(SIOCGIFCONF)
    if (ret)
	ret = getifaddrs2 (ifap, AF_INET6, SIOCGIFCONF, SIOCGIFFLAGS,
			   sizeof(struct ifreq));
#endif
#if defined(AF_INET) && defined(SIOCGIFCONF) && defined(SIOCGIFFLAGS)
    if (ret)
	ret = getifaddrs2 (ifap, AF_INET, SIOCGIFCONF, SIOCGIFFLAGS,
			   sizeof(struct ifreq));
#endif
    return ret;
}

void
freeifaddrs(struct ifaddrs *ifp)
{
    struct ifaddrs *p, *q;
    
    for(p = ifp; p; ) {
	free(p->ifa_name);
	if(p->ifa_addr)
	    free(p->ifa_addr);
	if(p->ifa_dstaddr) 
	    free(p->ifa_dstaddr);
	if(p->ifa_netmask) 
	    free(p->ifa_netmask);
	if(p->ifa_data)
	    free(p->ifa_data);
	q = p;
	p = p->ifa_next;
	free(q);
    }
}

#ifdef TEST

void
print_addr(const char *s, struct sockaddr *sa)
{
    int i;
    printf("  %s=%d/", s, sa->sa_family);
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
    for(i = 0; i < sa->sa_len - ((long)sa->sa_data - (long)&sa->sa_family); i++)
	printf("%02x", ((unsigned char*)sa->sa_data)[i]);
#else
    for(i = 0; i < sizeof(sa->sa_data); i++) 
	printf("%02x", ((unsigned char*)sa->sa_data)[i]);
#endif
    printf("\n");
}

void 
print_ifaddrs(struct ifaddrs *x)
{
    struct ifaddrs *p;
    
    for(p = x; p; p = p->ifa_next) {
	printf("%s\n", p->ifa_name);
	printf("  flags=%x\n", p->ifa_flags);
	if(p->ifa_addr)
	    print_addr("addr", p->ifa_addr);
	if(p->ifa_dstaddr) 
	    print_addr("dstaddr", p->ifa_dstaddr);
	if(p->ifa_netmask) 
	    print_addr("netmask", p->ifa_netmask);
	printf("  %p\n", p->ifa_data);
    }
}

int
main()
{
    struct ifaddrs *a = NULL, *b;
    getifaddrs2(&a, AF_INET, SIOCGIFCONF, SIOCGIFFLAGS, sizeof(struct ifreq));
    print_ifaddrs(a);
    printf("---\n");
    getifaddrs(&b);
    print_ifaddrs(b);
    return 0;
}
#endif
#endif