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__FBSDID("$FreeBSD$");
34
35// C++ STL and other related includes
36#include <stdlib.h>
37#include <limits.h>
38#include <iostream>
39#include <string.h>
40#include <string>
41
42// Operating System and other C based includes
43#include <unistd.h>
44#include <errno.h>
45#include <sys/types.h>
46#include <sys/time.h>
47#include <sys/socket.h>
48#include <sys/ioctl.h>
49#include <netinet/in.h>
50#include <net/if.h>
51#include <arpa/inet.h>
52
53// Private include files
54#include "mctest.h"
55
56using namespace std;
57
58//
59// usage - just the program's usage line
60//
61//
62void usage()
63{
64    cout << "mcgrab -i interface -g multicast group -n number of groups\n";
65    exit(-1);
66}
67
68//
69// usage - print out the usage with a possible message and exit
70//
71// \param message optional string
72//
73//
74void usage(string message)
75{
76
77    cerr << message << endl;
78    usage();
79}
80
81
82//
83// grab a set of addresses
84//
85// @param interface             ///< text name of the interface (em0 etc.)
86// @param group			///< multicast group
87// @param number		///< number of addresses to grab
88//
89// @return 0 for 0K, -1 for error, sets errno
90//
91void grab(char *interface, struct in_addr *group, int number, int block) {
92
93
94    int sock;
95    struct ip_mreq mreq;
96    struct ifreq ifreq;
97    struct in_addr lgroup;
98
99    if (group == NULL) {
100	group = &lgroup;
101	if (inet_pton(AF_INET, DEFAULT_GROUP, group) < 1)
102	    return;
103    }
104
105    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
106	perror("failed to open datagram socket");
107	return;
108    }
109
110    for (int i = 0; i < number; i++) {
111	bzero((struct ip_mreq *)&mreq, sizeof(mreq));
112	bzero((struct ifreq *)&ifreq, sizeof(ifreq));
113
114	strncpy(ifreq.ifr_name, interface, IFNAMSIZ);
115	if (ioctl(sock, SIOCGIFADDR, &ifreq) < 0) {
116	    perror("no such interface");
117	    return;
118	}
119
120	memcpy(&mreq.imr_interface,
121	       &((struct sockaddr_in*) &ifreq.ifr_addr)->sin_addr,
122	       sizeof(struct in_addr));
123
124	mreq.imr_multiaddr.s_addr = group->s_addr;
125	if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
126		       sizeof(mreq)) < 0) {
127
128	    perror("failed to add membership");
129	    return;
130	}
131
132	if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
133		       &((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr,
134		       sizeof(struct in_addr)) < 0) {
135	    perror("failed to bind interface");
136	    return;
137	}
138
139	group->s_addr = htonl(ntohl(group->s_addr) + 1);
140    }
141    if (block > 0) {
142	    printf("Press Control-C to exit.\n");
143	    sleep(INT_MAX);
144    }
145
146}
147
148
149//
150// main - the main program
151//
152// \param -g multicast group address which we will hold
153// \param -i interface on which we're holding the address
154//
155//
156int main(int argc, char**argv)
157{
158
159	char ch;		///< character from getopt()
160	extern char* optarg;	///< option argument
161
162	char* interface = 0;    ///< Name of the interface
163	struct in_addr *group = NULL;	///< the multicast group address
164	int number = 0;		///< Number of addresses to grab
165	int block = 1;		///< Do we block or just return?
166
167	if ((argc < 7) || (argc > 8))
168		usage();
169
170	while ((ch = getopt(argc, argv, "g:i:n:bh")) != -1) {
171		switch (ch) {
172		case 'g':
173			group = new (struct in_addr );
174			if (inet_pton(AF_INET, optarg, group) < 1)
175				usage(argv[0] + string(" Error: invalid multicast group") +
176				      optarg);
177			break;
178		case 'i':
179			interface = optarg;
180			break;
181		case 'n':
182			number = atoi(optarg);
183			break;
184		case 'b':
185			block = 0;
186			break;
187		case 'h':
188			usage(string("Help\n"));
189			break;
190		}
191	}
192
193	grab(interface, group, number, block);
194
195}
196