common-tools-tcp-burst/src/common/interface.c

/* $Id: interface.c 2423 2010-03-13 07:09:49Z aturner $ */

/*
 * Copyright (c) 2007-2010 Aaron Turner.
 * 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 names of the copyright owners 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 ``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 AUTHORS OR COPYRIGHT HOLDERS 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 <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>

#include "config.h"
#include "defines.h"
#include "common.h"
#include "interface.h"

/**
 * Method takes a user specified device name and returns
 * the canonical name for that device.  This allows me to 
 * create named interface aliases on platforms like Windows
 * which use horrifically long interface names
 * 
 * Returns NULL on error
 * 
 * On success, it *may* malloc() memory equal to the length of *alias.
 */
char *
get_interface(interface_list_t *list, const char *alias)
{
    interface_list_t *ptr;
    char *name;
    
    assert(alias);
    
    if (list != NULL) {        
        ptr = list;
    
        do {
            /* check both the alias & name fields */
            if (strcmp(alias, ptr->alias) == 0)
                return(ptr->name);
        
            if (strcmp(alias, ptr->name) == 0)
                return(ptr->name);
            
            ptr = ptr->next;
        } while (ptr != NULL);
    } else {
        name = (char *)safe_malloc(strlen(alias) + 1);
        memset(name, 0, strlen(alias) + 1);
        strncpy(name, alias, strlen(alias) + 1);
        return(name);
    }
    
    return(NULL);
}

/** 
 * Get all available interfaces as an interface_list *
 */
interface_list_t *
get_interface_list(void)
{
    interface_list_t *list_head, *list_ptr;
    char ebuf[PCAP_ERRBUF_SIZE];
    pcap_if_t *pcap_if, *pcap_if_ptr;
    int i = 0;
    
#ifndef HAVE_WIN32
	/* Unix just has a warning about being root */
	if (geteuid() != 0)
		warn("May need to run as root to get complete list.");
#endif

    if (pcap_findalldevs(&pcap_if, ebuf) < 0)
        errx(-1, "Error: %s", ebuf);
            
    pcap_if_ptr = pcap_if;
    list_head = (interface_list_t *)safe_malloc(sizeof(interface_list_t));
    list_ptr = list_head;
    
    while (pcap_if_ptr != NULL) {
        if (i > 0) {
            list_ptr->next = (interface_list_t *)safe_malloc(sizeof(interface_list_t));
            list_ptr = list_ptr->next;
        }
        strlcpy(list_ptr->name, pcap_if_ptr->name, sizeof(list_ptr->name));
        
        /* description is usually null under Unix */
        if (pcap_if_ptr->description != NULL)
            strlcpy(list_ptr->description, pcap_if_ptr->description, sizeof(list_ptr->description));
            
        sprintf(list_ptr->alias, "%%%d", i++);
        list_ptr->flags = pcap_if_ptr->flags;
        pcap_if_ptr = pcap_if_ptr->next;
    }
    pcap_freealldevs(pcap_if);
    return(list_head);
}

/**
 * Prints all the available interfaces found by get_interface_list()
 */
void
list_interfaces(interface_list_t *list)
{
    interface_list_t *ptr;

    if (list == NULL) {
        printf("No network interfaces available");
        return;
    }

    printf("Available network interfaces:\n");
        
#ifdef HAVE_WIN32  /* Win32 has alias/name/description */
	printf("Alias\tName\tDescription\n");
#endif
    
    
    ptr = list;

    do {
        if (! ptr->flags & PCAP_IF_LOOPBACK) {
#ifdef HAVE_WIN32
            printf("%s\t%s\n\t%s\n", ptr->alias, ptr->name, ptr->description);
#else
			printf("%s\n", ptr->name);
#endif
        }
        ptr = ptr->next;
    } while (ptr != NULL);
}