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/*
* Author: Steven Barth <steven at midlink.org>
*
* Copyright 2015 Deutsche Telekom AG
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may 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.
*
*/
#include <errno.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <net/if.h>
#include <string.h>
#include <unistd.h>
#include "querier.h"
// Test if multicast-group is valid and relevant
static inline bool igmp_is_valid_group(in_addr_t group)
{
return IN_MULTICAST(be32_to_cpu(group));
}
// Handle an IGMP-record from an IGMP-packet (called by igmp_receive)
static ssize_t igmp_handle_record(struct groups *groups, const uint8_t *data, size_t len)
{
struct igmpv3_grec *r = (struct igmpv3_grec*)data;
if (len < sizeof(*r))
return -1;
size_t nsrc = ntohs(r->grec_nsrcs);
size_t read = sizeof(*r) + nsrc * sizeof(struct in_addr) + r->grec_auxwords * 4;
if (len < read)
return -1;
if (r->grec_type >= UPDATE_IS_INCLUDE && r->grec_type <= UPDATE_BLOCK &&
igmp_is_valid_group(r->grec_mca)) {
struct in6_addr addr, sources[nsrc];
querier_map(&addr, r->grec_mca);
for (size_t i = 0; i < nsrc; ++i)
querier_map(&sources[i], r->grec_src[i]);
groups_update_state(groups, &addr, sources, nsrc, r->grec_type);
}
return read;
}
// Receive and parse an IGMP-packet (called by uloop as callback)
void igmp_handle(struct mrib_querier *mrib, const struct igmphdr *igmp, size_t len,
const struct sockaddr_in *from)
{
struct querier_iface *q = container_of(mrib, struct querier_iface, mrib);
omgp_time_t now = omgp_time();
char addrbuf[INET_ADDRSTRLEN];
struct in6_addr group;
querier_map(&group, igmp->group);
inet_ntop(AF_INET, &from->sin_addr, addrbuf, sizeof(addrbuf));
if (igmp->type == IGMP_HOST_MEMBERSHIP_QUERY) {
struct igmpv3_query *query = (struct igmpv3_query*)igmp;
if (len != sizeof(*igmp) && ((size_t)len < sizeof(*query) ||
(size_t)len < sizeof(*query) + ntohs(query->nsrcs) * sizeof(struct in_addr)))
return;
if (query->group && !igmp_is_valid_group(query->group))
return;
// Setup query target address
struct in_addr addr;
if (mrib_igmp_source(mrib, &addr))
return;
bool suppress = false;
size_t nsrc = 0;
int robustness = 2;
omgp_time_t mrd = 10000;
omgp_time_t query_interval = 125000;
if (igmp->code)
mrd = 100 * ((len == sizeof(*igmp)) ? igmp->code : querier_qqi(igmp->code));
if ((size_t)len > sizeof(*igmp)) {
if (query->qrv)
robustness = query->qrv;
if (query->qqic)
query_interval = querier_qqi(query->qqic) * 1000;
suppress = query->suppress;
nsrc = ntohs(query->nsrcs);
}
if (!suppress && query->group) {
struct in6_addr sources[nsrc];
for (size_t i = 0; i < nsrc; ++i)
querier_map(&sources[i], query->srcs[i]);
groups_update_timers(&q->groups, &group, sources, nsrc);
}
int election = memcmp(&from->sin_addr, &addr, sizeof(from->sin_addr));
L_INFO("%s: detected other querier %s with priority %d on %d",
__FUNCTION__, addrbuf, election, q->ifindex);
// TODO: we ignore IGMPv1/v2 queriers for now, since a lot of them are dumb switches
if (election < 0 && !query->group && len > sizeof(*igmp)) {
groups_update_config(&q->groups, false, mrd, query_interval, robustness);
q->igmp_other_querier = true;
q->igmp_next_query = now + (q->groups.cfg_v4.query_response_interval / 2) +
(q->groups.cfg_v4.robustness * q->groups.cfg_v4.query_interval);
}
} else if (igmp->type == IGMPV3_HOST_MEMBERSHIP_REPORT) {
struct igmpv3_report *report = (struct igmpv3_report*)igmp;
if ((size_t)len <= sizeof(*report))
return;
uint8_t *ibuf = (uint8_t*)igmp;
size_t count = ntohs(report->ngrec);
size_t offset = sizeof(*report);
while (count > 0 && offset < len) {
ssize_t read = igmp_handle_record(&q->groups, &ibuf[offset], len - offset);
if (read < 0)
break;
offset += read;
--count;
}
} else if (igmp->type == IGMPV2_HOST_MEMBERSHIP_REPORT ||
igmp->type == IGMP_HOST_LEAVE_MESSAGE ||
igmp->type == IGMP_HOST_MEMBERSHIP_REPORT) {
if (len != sizeof(*igmp) || !igmp_is_valid_group(igmp->group))
return;
groups_update_state(&q->groups, &group, NULL, 0,
(igmp->type == IGMPV2_HOST_MEMBERSHIP_REPORT) ? UPDATE_REPORT :
(igmp->type == IGMP_HOST_MEMBERSHIP_REPORT) ? UPDATE_REPORT_V1 : UPDATE_DONE);
}
uloop_timeout_set(&q->timeout, 0);
}
// Send generic / group-specific / group-and-source specific IGMP-query
int igmp_send_query(struct querier_iface *q,
const struct in6_addr *group,
const struct list_head *sources,
bool suppress)
{
uint8_t qqic = querier_qqic(((group) ? q->groups.cfg_v4.last_listener_query_interval :
q->groups.cfg_v4.query_response_interval) / 100);
struct {
struct igmpv3_query q;
struct in_addr srcs[QUERIER_MAX_SOURCE];
} query = {.q = {
.type = IGMP_HOST_MEMBERSHIP_QUERY,
.code = qqic,
.qrv = q->groups.cfg_v4.robustness,
.suppress = suppress,
.qqic = querier_qqic(q->groups.cfg_v4.query_interval / 1000),
}};
struct group_source *s;
size_t cnt = 0;
if (sources) {
list_for_each_entry(s, sources, head) {
if (cnt >= QUERIER_MAX_SOURCE) {
L_WARN("%s: maximum source count (%d) exceeded",
__FUNCTION__, QUERIER_MAX_SOURCE);
break;
}
query.q.srcs[cnt] = querier_unmap(&s->addr);
}
}
query.q.nsrcs = htons(cnt);
struct sockaddr_in dest = { .sin_family = AF_INET, .sin_addr = {htonl(0xe0000001U)}};
if (group) {
query.q.group = querier_unmap(group);
dest.sin_addr.s_addr = query.q.group;
}
return mrib_send_igmp(&q->mrib, &query.q,
sizeof(query.q) + cnt * sizeof(query.srcs[0]), &dest);
}
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