multicast.cc

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/*
 * Copyright (C) 1996-2025 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
/* DEBUG: section 07    Multicast */
 
#include "squid.h"
#include "comm/Connection.h"
#include "compat/socket.h"
#include "debug/Stream.h"
// XXX: for icpIncomingConn - need to pass it as a generic parameter.
#include "ICP.h"
#include "ipcache.h"
#include "multicast.h"
 
int
mcastSetTtl(int fd, int mcast_ttl)
{
#ifdef IP_MULTICAST_TTL
    char ttl = (char) mcast_ttl;
 
    if (xsetsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, 1) < 0) {
        int xerrno = errno;
        debugs(50, DBG_IMPORTANT, "mcastSetTtl: FD " << fd << ", TTL: " << mcast_ttl << ": " << xstrerr(xerrno));
    }
#endif
 
    return 0;
}
 
void
mcastJoinGroups(const ipcache_addrs *ia, const Dns::LookupDetails &, void *)
{
#ifdef IP_MULTICAST_TTL
    struct ip_mreq mr;
 
    if (ia == nullptr) {
        debugs(7, DBG_CRITICAL, "ERROR: comm_join_mcast_groups: Unknown host");
        return;
    }
 
    for (const auto &ip: ia->goodAndBad()) { // TODO: Consider using just good().
        debugs(7, 9, "Listening for ICP requests on " << ip);
 
        if (!ip.isIPv4()) {
            debugs(7, 9, "ERROR: IPv6 Multicast Listen has not been implemented!");
            continue;
        }
 
        ip.getInAddr(mr.imr_multiaddr);
 
        mr.imr_interface.s_addr = INADDR_ANY;
 
        if (xsetsockopt(icpIncomingConn->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mr, sizeof(struct ip_mreq)) < 0)
            debugs(7, DBG_IMPORTANT, "ERROR: Join failed for " << icpIncomingConn << ", Multicast IP=" << ip);
 
        char c = 0;
        if (xsetsockopt(icpIncomingConn->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &c, 1) < 0) {
            int xerrno = errno;
            debugs(7, DBG_IMPORTANT, "ERROR: " << icpIncomingConn << " can't disable multicast loopback: " << xstrerr(xerrno));
        }
    }
 
#endif
}