1//
2//  Copyright (c) 2008, Neville-Neil Consulting
3//  All rights reserved.
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions
7// are met:
8// 1. Redistributions of source code must retain the above copyright
9//    notice, this list of conditions and the following disclaimer.
10// 2. Redistributions in binary form must reproduce the above copyright
11//    notice, this list of conditions and the following disclaimer in the
12//    documentation and/or other materials provided with the distribution.
13//
14// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24// SUCH DAMAGE.
25//
26//  This test simply grabs N multicast addresses starting
27//  from a base address.  The purpose is to make sure that switching a device
28//  from using a multicast filtering table or function to promiscuous
29//  multicast listening mode does not cause deleterious side effects.
30//
31
32#include <sys/cdefs.h>
33// C++ STL and other related includes
34#include <stdlib.h>
35#include <limits.h>
36#include <iostream>
37#include <string.h>
38#include <string>
39
40// Operating System and other C based includes
41#include <unistd.h>
42#include <errno.h>
43#include <sys/types.h>
44#include <sys/time.h>
45#include <sys/socket.h>
46#include <sys/ioctl.h>
47#include <netinet/in.h>
48#include <net/if.h>
49#include <arpa/inet.h>
50
51// Private include files
52#include "mctest.h"
53
54using namespace std;
55
56//
57// usage - just the program's usage line
58//
59//
60void usage()
61{
62    cout << "mcgrab -i interface -g multicast group -n number of groups\n";
63    exit(-1);
64}
65
66//
67// usage - print out the usage with a possible message and exit
68//
69// \param message optional string
70//
71//
72void usage(string message)
73{
74
75    cerr << message << endl;
76    usage();
77}
78
79
80//
81// grab a set of addresses
82//
83// @param interface             ///< text name of the interface (em0 etc.)
84// @param group			///< multicast group
85// @param number		///< number of addresses to grab
86//
87// @return 0 for 0K, -1 for error, sets errno
88//
89void grab(char *interface, struct in_addr *group, int number, int block) {
90
91
92    int sock;
93    struct ip_mreq mreq;
94    struct ifreq ifreq;
95    struct in_addr lgroup;
96
97    if (group == NULL) {
98	group = &lgroup;
99	if (inet_pton(AF_INET, DEFAULT_GROUP, group) < 1)
100	    return;
101    }
102
103    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
104	perror("failed to open datagram socket");
105	return;
106    }
107
108    for (int i = 0; i < number; i++) {
109	bzero((struct ip_mreq *)&mreq, sizeof(mreq));
110	bzero((struct ifreq *)&ifreq, sizeof(ifreq));
111
112	strncpy(ifreq.ifr_name, interface, IFNAMSIZ);
113	if (ioctl(sock, SIOCGIFADDR, &ifreq) < 0) {
114	    perror("no such interface");
115	    return;
116	}
117
118	memcpy(&mreq.imr_interface,
119	       &((struct sockaddr_in*) &ifreq.ifr_addr)->sin_addr,
120	       sizeof(struct in_addr));
121
122	mreq.imr_multiaddr.s_addr = group->s_addr;
123	if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
124		       sizeof(mreq)) < 0) {
125
126	    perror("failed to add membership");
127	    return;
128	}
129
130	if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
131		       &((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr,
132		       sizeof(struct in_addr)) < 0) {
133	    perror("failed to bind interface");
134	    return;
135	}
136
137	group->s_addr = htonl(ntohl(group->s_addr) + 1);
138    }
139    if (block > 0) {
140	    printf("Press Control-C to exit.\n");
141	    sleep(INT_MAX);
142    }
143
144}
145
146
147//
148// main - the main program
149//
150// \param -g multicast group address which we will hold
151// \param -i interface on which we're holding the address
152//
153//
154int main(int argc, char**argv)
155{
156
157	char ch;		///< character from getopt()
158	extern char* optarg;	///< option argument
159
160	char* interface = 0;    ///< Name of the interface
161	struct in_addr *group = NULL;	///< the multicast group address
162	int number = 0;		///< Number of addresses to grab
163	int block = 1;		///< Do we block or just return?
164
165	if ((argc < 7) || (argc > 8))
166		usage();
167
168	while ((ch = getopt(argc, argv, "g:i:n:bh")) != -1) {
169		switch (ch) {
170		case 'g':
171			group = new (struct in_addr );
172			if (inet_pton(AF_INET, optarg, group) < 1)
173				usage(argv[0] + string(" Error: invalid multicast group") +
174				      optarg);
175			break;
176		case 'i':
177			interface = optarg;
178			break;
179		case 'n':
180			number = atoi(optarg);
181			break;
182		case 'b':
183			block = 0;
184			break;
185		case 'h':
186			usage(string("Help\n"));
187			break;
188		}
189	}
190
191	grab(interface, group, number, block);
192
193}
194