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/**************************************************************************
*
* Copyright (c) 2013 Alcatel-Lucent
*
* Alcatel Lucent licenses this file to You under the Apache License,
* Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. A copy of the License is contained the
* file LICENSE at the top level of this repository.
* You may also obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
**************************************************************************
*
* igmp.c:
*
* Support some basic IGMP stuff.
* I wrote this code as an exercise for getting to know basic IGMP.
* This code doesn't do much. It will successfully send a JOIN or LEAVE
* but the monitor is not prepared to deal with multicast, so it doesn't
* add any real functionality except for the ability to observe IGMP.
*
* Original author: Ed Sutter (ed.sutter@alcatel-lucent.com)
*
*/
#include "config.h"
#if INCLUDE_IGMP
#include "endian.h"
#include "genlib.h"
#include "ether.h"
#include "stddefs.h"
#include "cli.h"
int SendIGMP(int type,uchar *groupip);
char *IgmpHelp[] = {
"IGMP interface",
#if INCLUDE_VERBOSEHELP
"{operation} [args]",
"Operations...",
" join {IP}",
" leave {IP}",
#endif
0,
};
int
Igmp(int argc,char *argv[])
{
int opt, verbose = 0;
uchar binip[8];
char *operation, *ipadd;
while ((opt=getopt(argc,argv,"v")) != -1) {
switch(opt) {
case 'v':
verbose = 1;
break;
default:
return(CMD_PARAM_ERROR);
}
}
if (argc != optind + 2)
return(CMD_PARAM_ERROR);
operation = argv[optind];
ipadd = argv[optind+1];
/* Convert IP address to binary: */
if (IpToBin(ipadd,binip) < 0)
return(CMD_SUCCESS);
/* If time or echo, do the common up-front stuff here... */
if (!strcmp(operation,"join")) {
SendIGMP(IGMPTYPE_JOIN,binip);
}
else if (!strcmp(operation,"leave")) {
SendIGMP(IGMPTYPE_LEAVE,binip);
}
else {
printf("Unrecognized IGMP op: %s\n",operation);
return(CMD_FAILURE);
}
return(CMD_SUCCESS);
}
int
SendIGMP(int type,uchar *groupip)
{
int i;
ushort *sp;
struct ip *ti;
struct Igmphdr *tigmp;
struct ether_header *te;
ulong csum, *router_alert_opt;
/* Retrieve an ethernet buffer from the driver and populate the */
/* ethernet level of packet: */
te = (struct ether_header *) getXmitBuffer();
/* Source MAC is this target's MAC address...
*/
memcpy((char *)&te->ether_shost,(char *)BinEnetAddr,6);
/* Destination MAC is multicast, so it is derived from the
* group IP address...
* The upper 24 bits are 0x01005e.
* For JOIN, the lower 24 bits are masked with the groupIP and 0x7fffff.
* For LEAVE, the message is sent to the All_Routers_Multicast_Group
* (224.0.0.2), so the lower three bytes are 0,0,2.
*/
te->ether_dhost.ether_addr_octet[0] = 0x01;
te->ether_dhost.ether_addr_octet[1] = 0x00;
te->ether_dhost.ether_addr_octet[2] = 0x5e;
if (type == IGMPTYPE_LEAVE) {
te->ether_dhost.ether_addr_octet[3] = 0x00;
te->ether_dhost.ether_addr_octet[4] = 0x00;
te->ether_dhost.ether_addr_octet[5] = 0x02;
}
else {
te->ether_dhost.ether_addr_octet[3] = groupip[1] & 0x7f;
te->ether_dhost.ether_addr_octet[4] = groupip[2];
te->ether_dhost.ether_addr_octet[5] = groupip[3];
}
te->ether_type = ecs(ETHERTYPE_IP);
/* Move to the IP portion of the packet and populate it appropriately: */
ti = (struct ip *) (te + 1);
ti->ip_vhl = ((IP_VER<<4) | ((sizeof(struct ip)+sizeof(ulong)) >> 2));
ti->ip_tos = 0;
ti->ip_len = sizeof(struct ip) + sizeof(ulong) + sizeof(struct Igmphdr);
ti->ip_id = ipId();
ti->ip_off = 0;
ti->ip_ttl = 1;
ti->ip_p = IP_IGMP;
memcpy((char *)&ti->ip_src.s_addr,(char *)BinIpAddr,4);
if (type == IGMPTYPE_LEAVE)
ti->ip_dst.s_addr = ALL_MULTICAST_ROUTERS;
else
memcpy((char *)&ti->ip_dst.s_addr,(char *)groupip,4);
self_ecs(ti->ip_len);
self_ecs(ti->ip_off);
self_ecs(ti->ip_id);
router_alert_opt = (ulong *)(ti+1);
*router_alert_opt = 0x94040000; /* see RFC2113 */
ipChksum(ti); /* Compute csum of ip hdr */
/* Move to the IGMP portion of the packet and populate it appropriately: */
tigmp = (struct Igmphdr *)(router_alert_opt+1);
tigmp->type = type;
tigmp->mrt = 0;
tigmp->csum = 0;
memcpy((char *)&tigmp->group,(char *)groupip,4);
/* Calculate checksum of IGMP portion of the header.
* This uses the same method as is used with ipChksum()...
*/
sp = (ushort *)tigmp;
csum = 0;
for (i=0;i<4;i++,sp++) {
csum += *sp;
if (csum & 0x80000000)
csum = (csum & 0xffff) + (csum >> 16);
}
while(csum >> 16)
csum = (csum & 0xffff) + (csum >> 16);
tigmp->csum = ~csum;
sendBuffer(IGMP_JOINRQSTSIZE);
return(0);
}
int
MacIsMulticast(uchar *mac)
{
if (*mac != 0x01)
return(0);
mac++;
if (*mac != 0x00)
return(0);
mac++;
if (*mac != 0x5e)
return(0);
mac++;
if (*mac & 0x80)
return(0);
return(1);
}
#endif
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