n2n/sn_utils.c

#include "n2n.h"

#define HASH_FIND_COMMUNITY(head, name, out) HASH_FIND_STR(head, name, out)
#define N2N_SN_LPORT_DEFAULT 7654
#define N2N_SN_PKTBUF_SIZE 2048

static int try_forward(n2n_sn_t *sss,
                       const n2n_common_t *cmn,
                       const n2n_mac_t dstMac,
                       const uint8_t *pktbuf,
                       size_t pktsize);

static ssize_t sendto_sock(n2n_sn_t *sss,
                           const n2n_sock_t *sock,
                           const uint8_t *pktbuf,
                           size_t pktsize);

static int try_broadcast(n2n_sn_t *sss,
                         const n2n_common_t *cmn,
                         const n2n_mac_t srcMac,
                         const uint8_t *pktbuf,
                         size_t pktsize);

static uint16_t reg_lifetime(n2n_sn_t *sss);

static int update_edge(n2n_sn_t *sss,
                       const n2n_mac_t edgeMac,
                       struct sn_community *comm,
                       const n2n_sock_t *sender_sock,
                       time_t now);

static int process_mgmt(n2n_sn_t *sss,
                        const struct sockaddr_in *sender_sock,
                        const uint8_t *mgmt_buf,
                        size_t mgmt_size,
                        time_t now);

static int process_udp(n2n_sn_t *sss,
                       const struct sockaddr_in *sender_sock,
                       const uint8_t *udp_buf,
                       size_t udp_size,
                       time_t now);

static int try_forward(n2n_sn_t *sss,
                       const n2n_common_t *cmn,
                       const n2n_mac_t dstMac,
                       const uint8_t *pktbuf,
                       size_t pktsize)
{
    struct peer_info *scan;
    struct sn_community *community;
    macstr_t mac_buf;
    n2n_sock_str_t sockbuf;

    HASH_FIND_COMMUNITY(sss->communities, (char *)cmn->community, community);

    if (!community)
    {
        traceEvent(TRACE_DEBUG, "try_forward unknown community %s", cmn->community);
        return (-1);
    }

    HASH_FIND_PEER(community->edges, dstMac, scan);

    if (NULL != scan)
    {
        int data_sent_len;
        data_sent_len = sendto_sock(sss, &(scan->sock), pktbuf, pktsize);

        if (data_sent_len == pktsize)
        {
            ++(sss->stats.fwd);
            traceEvent(TRACE_DEBUG, "unicast %lu to [%s] %s",
                       pktsize,
                       sock_to_cstr(sockbuf, &(scan->sock)),
                       macaddr_str(mac_buf, scan->mac_addr));
        }
        else
        {
            ++(sss->stats.errors);
            traceEvent(TRACE_ERROR, "unicast %lu to [%s] %s FAILED (%d: %s)",
                       pktsize,
                       sock_to_cstr(sockbuf, &(scan->sock)),
                       macaddr_str(mac_buf, scan->mac_addr),
                       errno, strerror(errno));
        }
    }
    else
    {
        traceEvent(TRACE_DEBUG, "try_forward unknown MAC");

        /* Not a known MAC so drop. */
        return (-2);
    }

    return (0);
}

/** Send a datagram to the destination embodied in a n2n_sock_t.
 *
 *  @return -1 on error otherwise number of bytes sent
 */
static ssize_t sendto_sock(n2n_sn_t *sss,
                           const n2n_sock_t *sock,
                           const uint8_t *pktbuf,
                           size_t pktsize)
{
    n2n_sock_str_t sockbuf;

    if (AF_INET == sock->family)
    {
        struct sockaddr_in udpsock;

        udpsock.sin_family = AF_INET;
        udpsock.sin_port = htons(sock->port);
        memcpy(&(udpsock.sin_addr.s_addr), &(sock->addr.v4), IPV4_SIZE);

        traceEvent(TRACE_DEBUG, "sendto_sock %lu to [%s]",
                   pktsize,
                   sock_to_cstr(sockbuf, sock));

        return sendto(sss->sock, pktbuf, pktsize, 0,
                      (const struct sockaddr *)&udpsock, sizeof(struct sockaddr_in));
    }
    else
    {
        /* AF_INET6 not implemented */
        errno = EAFNOSUPPORT;
        return -1;
    }
}

/** Try and broadcast a message to all edges in the community.
 *
 *  This will send the exact same datagram to zero or more edges registered to
 *  the supernode.
 */
static int try_broadcast(n2n_sn_t *sss,
                         const n2n_common_t *cmn,
                         const n2n_mac_t srcMac,
                         const uint8_t *pktbuf,
                         size_t pktsize)
{
    struct peer_info *scan, *tmp;
    struct sn_community *community;
    macstr_t mac_buf;
    n2n_sock_str_t sockbuf;

    traceEvent(TRACE_DEBUG, "try_broadcast");

    HASH_FIND_COMMUNITY(sss->communities, (char *)cmn->community, community);

    if (community)
    {
        HASH_ITER(hh, community->edges, scan, tmp)
        {
            if (memcmp(srcMac, scan->mac_addr, sizeof(n2n_mac_t)) != 0)
            {
                /* REVISIT: exclude if the destination socket is where the packet came from. */
                int data_sent_len;

                data_sent_len = sendto_sock(sss, &(scan->sock), pktbuf, pktsize);

                if (data_sent_len != pktsize)
                {
                    ++(sss->stats.errors);
                    traceEvent(TRACE_WARNING, "multicast %lu to [%s] %s failed %s",
                               pktsize,
                               sock_to_cstr(sockbuf, &(scan->sock)),
                               macaddr_str(mac_buf, scan->mac_addr),
                               strerror(errno));
                }
                else
                {
                    ++(sss->stats.broadcast);
                    traceEvent(TRACE_DEBUG, "multicast %lu to [%s] %s",
                               pktsize,
                               sock_to_cstr(sockbuf, &(scan->sock)),
                               macaddr_str(mac_buf, scan->mac_addr));
                }
            }
        }
    }
    else
        traceEvent(TRACE_INFO, "ignoring broadcast on unknown community %s\n",
                   cmn->community);

    return 0;
}

/** Initialise the supernode structure */
int sn_init(n2n_sn_t *sss)
{
#ifdef WIN32
    initWin32();
#endif
    memset(sss, 0, sizeof(n2n_sn_t));

    sss->daemon = 1; /* By defult run as a daemon. */
    sss->lport = N2N_SN_LPORT_DEFAULT;
    sss->sock = -1;
    sss->mgmt_sock = -1;

    return 0; /* OK */
}

/** Deinitialise the supernode structure and deallocate any memory owned by
 *  it. */
void sn_term(n2n_sn_t *sss)
{
    struct sn_community *community, *tmp;

    if (sss->sock >= 0)
    {
        closesocket(sss->sock);
    }
    sss->sock = -1;

    if (sss->mgmt_sock >= 0)
    {
        closesocket(sss->mgmt_sock);
    }
    sss->mgmt_sock = -1;

    HASH_ITER(hh, sss->communities, community, tmp)
    {
        clear_peer_list(&community->edges);
        HASH_DEL(sss->communities, community);
        free(community);
    }
}

/** Determine the appropriate lifetime for new registrations.
 *
 *  If the supernode has been put into a pre-shutdown phase then this lifetime
 *  should not allow registrations to continue beyond the shutdown point.
 */
static uint16_t reg_lifetime(n2n_sn_t *sss)
{
    /* NOTE: UDP firewalls usually have a 30 seconds timeout */
    return 15;
}

/** Update the edge table with the details of the edge which contacted the
 *  supernode. */
static int update_edge(n2n_sn_t *sss,
                       const n2n_mac_t edgeMac,
                       struct sn_community *comm,
                       const n2n_sock_t *sender_sock,
                       time_t now)
{
    macstr_t mac_buf;
    n2n_sock_str_t sockbuf;
    struct peer_info *scan;

    traceEvent(TRACE_DEBUG, "update_edge for %s [%s]",
               macaddr_str(mac_buf, edgeMac),
               sock_to_cstr(sockbuf, sender_sock));

    HASH_FIND_PEER(comm->edges, edgeMac, scan);

    if (NULL == scan)
    {
        /* Not known */

        scan = (struct peer_info *)calloc(1,
                                          sizeof(struct peer_info)); /* deallocated in purge_expired_registrations */

        memcpy(&(scan->mac_addr), edgeMac, sizeof(n2n_mac_t));
        memcpy(&(scan->sock), sender_sock, sizeof(n2n_sock_t));

        HASH_ADD_PEER(comm->edges, scan);

        traceEvent(TRACE_INFO, "update_edge created   %s ==> %s",
                   macaddr_str(mac_buf, edgeMac),
                   sock_to_cstr(sockbuf, sender_sock));
    }
    else
    {
        /* Known */
        if (!sock_equal(sender_sock, &(scan->sock)))
        {
            memcpy(&(scan->sock), sender_sock, sizeof(n2n_sock_t));

            traceEvent(TRACE_INFO, "update_edge updated   %s ==> %s",
                       macaddr_str(mac_buf, edgeMac),
                       sock_to_cstr(sockbuf, sender_sock));
        }
        else
        {
            traceEvent(TRACE_DEBUG, "update_edge unchanged %s ==> %s",
                       macaddr_str(mac_buf, edgeMac),
                       sock_to_cstr(sockbuf, sender_sock));
        }
    }

    scan->last_seen = now;
    return 0;
}

static int process_mgmt(n2n_sn_t *sss,
                        const struct sockaddr_in *sender_sock,
                        const uint8_t *mgmt_buf,
                        size_t mgmt_size,
                        time_t now)
{
    char resbuf[N2N_SN_PKTBUF_SIZE];
    size_t ressize = 0;
    uint32_t num_edges = 0;
    ssize_t r;
    struct sn_community *community, *tmp;

    traceEvent(TRACE_DEBUG, "process_mgmt");

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "----------------\n");

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "uptime    %lu\n", (now - sss->start_time));

    HASH_ITER(hh, sss->communities, community, tmp)
    {
        num_edges += HASH_COUNT(community->edges);
    }

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "edges     %u\n",
                        num_edges);

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "errors    %u\n",
                        (unsigned int)sss->stats.errors);

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "reg_sup   %u\n",
                        (unsigned int)sss->stats.reg_super);

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "reg_nak   %u\n",
                        (unsigned int)sss->stats.reg_super_nak);

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "fwd       %u\n",
                        (unsigned int)sss->stats.fwd);

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "broadcast %u\n",
                        (unsigned int)sss->stats.broadcast);

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "last fwd  %lu sec ago\n",
                        (long unsigned int)(now - sss->stats.last_fwd));

    ressize += snprintf(resbuf + ressize, N2N_SN_PKTBUF_SIZE - ressize,
                        "last reg  %lu sec ago\n",
                        (long unsigned int)(now - sss->stats.last_reg_super));

    r = sendto(sss->mgmt_sock, resbuf, ressize, 0 /*flags*/,
               (struct sockaddr *)sender_sock, sizeof(struct sockaddr_in));

    if (r <= 0)
    {
        ++(sss->stats.errors);
        traceEvent(TRACE_ERROR, "process_mgmt : sendto failed. %s", strerror(errno));
    }

    return 0;
}

/** Examine a datagram and determine what to do with it.
 *
 */
static int process_udp(n2n_sn_t *sss,
                       const struct sockaddr_in *sender_sock,
                       const uint8_t *udp_buf,
                       size_t udp_size,
                       time_t now)
{
    n2n_common_t cmn; /* common fields in the packet header */
    size_t rem;
    size_t idx;
    size_t msg_type;
    uint8_t from_supernode;
    macstr_t mac_buf;
    macstr_t mac_buf2;
    n2n_sock_str_t sockbuf;
    char buf[32];

    traceEvent(TRACE_DEBUG, "Processing incoming UDP packet [len: %lu][sender: %s:%u]",
               udp_size, intoa(ntohl(sender_sock->sin_addr.s_addr), buf, sizeof(buf)),
               ntohs(sender_sock->sin_port));

    /* Use decode_common() to determine the kind of packet then process it:
     *
     * REGISTER_SUPER adds an edge and generate a return REGISTER_SUPER_ACK
     *
     * REGISTER, REGISTER_ACK and PACKET messages are forwarded to their
     * destination edge. If the destination is not known then PACKETs are
     * broadcast.
     */

    rem = udp_size; /* Counts down bytes of packet to protect against buffer overruns. */
    idx = 0;        /* marches through packet header as parts are decoded. */
    if (decode_common(&cmn, udp_buf, &rem, &idx) < 0)
    {
        traceEvent(TRACE_ERROR, "Failed to decode common section");
        return -1; /* failed to decode packet */
    }

    msg_type = cmn.pc; /* packet code */
    from_supernode = cmn.flags & N2N_FLAGS_FROM_SUPERNODE;

    if (cmn.ttl < 1)
    {
        traceEvent(TRACE_WARNING, "Expired TTL");
        return 0; /* Don't process further */
    }

    --(cmn.ttl); /* The value copied into all forwarded packets. */

    switch (msg_type)
    {
    case MSG_TYPE_PACKET:
    {
        /* PACKET from one edge to another edge via supernode. */

        /* pkt will be modified in place and recoded to an output of potentially
             * different size due to addition of the socket.*/
        n2n_PACKET_t pkt;
        n2n_common_t cmn2;
        uint8_t encbuf[N2N_SN_PKTBUF_SIZE];
        size_t encx = 0;
        int unicast;            /* non-zero if unicast */
        const uint8_t *rec_buf; /* either udp_buf or encbuf */

        sss->stats.last_fwd = now;
        decode_PACKET(&pkt, &cmn, udp_buf, &rem, &idx);

        unicast = (0 == is_multi_broadcast(pkt.dstMac));

        traceEvent(TRACE_DEBUG, "RX PACKET (%s) %s -> %s %s",
                   (unicast ? "unicast" : "multicast"),
                   macaddr_str(mac_buf, pkt.srcMac),
                   macaddr_str(mac_buf2, pkt.dstMac),
                   (from_supernode ? "from sn" : "local"));

        if (!from_supernode)
        {
            memcpy(&cmn2, &cmn, sizeof(n2n_common_t));

            /* We are going to add socket even if it was not there before */
            cmn2.flags |= N2N_FLAGS_SOCKET | N2N_FLAGS_FROM_SUPERNODE;

            pkt.sock.family = AF_INET;
            pkt.sock.port = ntohs(sender_sock->sin_port);
            memcpy(pkt.sock.addr.v4, &(sender_sock->sin_addr.s_addr), IPV4_SIZE);

            rec_buf = encbuf;

            /* Re-encode the header. */
            encode_PACKET(encbuf, &encx, &cmn2, &pkt);

            /* Copy the original payload unchanged */
            encode_buf(encbuf, &encx, (udp_buf + idx), (udp_size - idx));
        }
        else
        {
            /* Already from a supernode. Nothing to modify, just pass to
                 * destination. */

            traceEvent(TRACE_DEBUG, "Rx PACKET fwd unmodified");

            rec_buf = udp_buf;
            encx = udp_size;
        }

        /* Common section to forward the final product. */
        if (unicast)
            try_forward(sss, &cmn, pkt.dstMac, rec_buf, encx);
        else
            try_broadcast(sss, &cmn, pkt.srcMac, rec_buf, encx);
        break;
    }
    case MSG_TYPE_REGISTER:
    {
        /* Forwarding a REGISTER from one edge to the next */

        n2n_REGISTER_t reg;
        n2n_common_t cmn2;
        uint8_t encbuf[N2N_SN_PKTBUF_SIZE];
        size_t encx = 0;
        int unicast;            /* non-zero if unicast */
        const uint8_t *rec_buf; /* either udp_buf or encbuf */

        sss->stats.last_fwd = now;
        decode_REGISTER(&reg, &cmn, udp_buf, &rem, &idx);

        unicast = (0 == is_multi_broadcast(reg.dstMac));

        if (unicast)
        {
            traceEvent(TRACE_DEBUG, "Rx REGISTER %s -> %s %s",
                       macaddr_str(mac_buf, reg.srcMac),
                       macaddr_str(mac_buf2, reg.dstMac),
                       ((cmn.flags & N2N_FLAGS_FROM_SUPERNODE) ? "from sn" : "local"));

            if (0 == (cmn.flags & N2N_FLAGS_FROM_SUPERNODE))
            {
                memcpy(&cmn2, &cmn, sizeof(n2n_common_t));

                /* We are going to add socket even if it was not there before */
                cmn2.flags |= N2N_FLAGS_SOCKET | N2N_FLAGS_FROM_SUPERNODE;

                reg.sock.family = AF_INET;
                reg.sock.port = ntohs(sender_sock->sin_port);
                memcpy(reg.sock.addr.v4, &(sender_sock->sin_addr.s_addr), IPV4_SIZE);

                rec_buf = encbuf;

                /* Re-encode the header. */
                encode_REGISTER(encbuf, &encx, &cmn2, &reg);

                /* Copy the original payload unchanged */
                encode_buf(encbuf, &encx, (udp_buf + idx), (udp_size - idx));
            }
            else
            {
                /* Already from a supernode. Nothing to modify, just pass to
                     * destination. */

                rec_buf = udp_buf;
                encx = udp_size;
            }

            try_forward(sss, &cmn, reg.dstMac, rec_buf, encx); /* unicast only */
        }
        else
            traceEvent(TRACE_ERROR, "Rx REGISTER with multicast destination");
        break;
    }
    case MSG_TYPE_REGISTER_ACK:
        traceEvent(TRACE_DEBUG, "Rx REGISTER_ACK (NOT IMPLEMENTED) SHould not be via supernode");
        break;
    case MSG_TYPE_REGISTER_SUPER:
    {
        n2n_REGISTER_SUPER_t reg;
        n2n_REGISTER_SUPER_ACK_t ack;
        n2n_common_t cmn2;
        uint8_t ackbuf[N2N_SN_PKTBUF_SIZE];
        size_t encx = 0;
        struct sn_community *comm;

        /* Edge requesting registration with us.  */
        sss->stats.last_reg_super = now;
        ++(sss->stats.reg_super);
        decode_REGISTER_SUPER(&reg, &cmn, udp_buf, &rem, &idx);

        HASH_FIND_COMMUNITY(sss->communities, (char *)cmn.community, comm);

        /*
              Before we move any further, we need to check if the requested
              community is allowed by the supernode. In case it is not we do
              not report any message back to the edge to hide the supernode
              existance (better from the security standpoint)
            */
        if (!comm && !sss->lock_communities)
        {
            comm = calloc(1, sizeof(struct sn_community));

            if (comm)
            {
                strncpy(comm->community, (char *)cmn.community, N2N_COMMUNITY_SIZE - 1);
                comm->community[N2N_COMMUNITY_SIZE - 1] = '\0';
                HASH_ADD_STR(sss->communities, community, comm);

                traceEvent(TRACE_INFO, "New community: %s", comm->community);
            }
        }

        if (comm)
        {
            cmn2.ttl = N2N_DEFAULT_TTL;
            cmn2.pc = n2n_register_super_ack;
            cmn2.flags = N2N_FLAGS_SOCKET | N2N_FLAGS_FROM_SUPERNODE;
            memcpy(cmn2.community, cmn.community, sizeof(n2n_community_t));

            memcpy(&(ack.cookie), &(reg.cookie), sizeof(n2n_cookie_t));
            memcpy(ack.edgeMac, reg.edgeMac, sizeof(n2n_mac_t));
            ack.lifetime = reg_lifetime(sss);

            ack.sock.family = AF_INET;
            ack.sock.port = ntohs(sender_sock->sin_port);
            memcpy(ack.sock.addr.v4, &(sender_sock->sin_addr.s_addr), IPV4_SIZE);

            ack.num_sn = 0; /* No backup */
            memset(&(ack.sn_bak), 0, sizeof(n2n_sock_t));

            traceEvent(TRACE_DEBUG, "Rx REGISTER_SUPER for %s [%s]",
                       macaddr_str(mac_buf, reg.edgeMac),
                       sock_to_cstr(sockbuf, &(ack.sock)));

            update_edge(sss, reg.edgeMac, comm, &(ack.sock), now);

            encode_REGISTER_SUPER_ACK(ackbuf, &encx, &cmn2, &ack);

            sendto(sss->sock, ackbuf, encx, 0,
                   (struct sockaddr *)sender_sock, sizeof(struct sockaddr_in));

            traceEvent(TRACE_DEBUG, "Tx REGISTER_SUPER_ACK for %s [%s]",
                       macaddr_str(mac_buf, reg.edgeMac),
                       sock_to_cstr(sockbuf, &(ack.sock)));
        }
        else
            traceEvent(TRACE_INFO, "Discarded registration: unallowed community '%s'",
                       (char *)cmn.community);
        break;
    }
    case MSG_TYPE_QUERY_PEER:
    {
        n2n_QUERY_PEER_t query;
        uint8_t encbuf[N2N_SN_PKTBUF_SIZE];
        size_t encx = 0;
        n2n_common_t cmn2;
        n2n_PEER_INFO_t pi;
        struct sn_community *community;

        decode_QUERY_PEER(&query, &cmn, udp_buf, &rem, &idx);

        traceEvent(TRACE_DEBUG, "Rx QUERY_PEER from %s for %s",
                   macaddr_str(mac_buf, query.srcMac),
                   macaddr_str(mac_buf2, query.targetMac));

        HASH_FIND_COMMUNITY(sss->communities, (char *)cmn.community, community);

        if (community)
        {
            struct peer_info *scan;
            HASH_FIND_PEER(community->edges, query.targetMac, scan);

            if (scan)
            {
                cmn2.ttl = N2N_DEFAULT_TTL;
                cmn2.pc = n2n_peer_info;
                cmn2.flags = N2N_FLAGS_FROM_SUPERNODE;
                memcpy(cmn2.community, cmn.community, sizeof(n2n_community_t));

                pi.aflags = 0;
                memcpy(pi.mac, query.targetMac, sizeof(n2n_mac_t));
                pi.sock = scan->sock;

                encode_PEER_INFO(encbuf, &encx, &cmn2, &pi);

                sendto(sss->sock, encbuf, encx, 0,
                       (struct sockaddr *)sender_sock, sizeof(struct sockaddr_in));

                traceEvent(TRACE_DEBUG, "Tx PEER_INFO to %s",
                           macaddr_str(mac_buf, query.srcMac));
            }
            else
            {
                traceEvent(TRACE_DEBUG, "Ignoring QUERY_PEER for unknown edge %s",
                           macaddr_str(mac_buf, query.targetMac));
            }
        }

        break;
    }
    default:
        /* Not a known message type */
        traceEvent(TRACE_WARNING, "Unable to handle packet type %d: ignored", (signed int)msg_type);
    } /* switch(msg_type) */

    return 0;
}

/** Long lived processing entry point. Split out from main to simply
 *  daemonisation on some platforms. */
int run_sn_loop(n2n_sn_t *sss, int *keep_running)
{
    uint8_t pktbuf[N2N_SN_PKTBUF_SIZE];
    time_t last_purge_edges = 0;
    struct sn_community *comm, *tmp;

    sss->start_time = time(NULL);

    while (*keep_running)
    {
        int rc;
        ssize_t bread;
        int max_sock;
        fd_set socket_mask;
        struct timeval wait_time;
        time_t now = 0;

        FD_ZERO(&socket_mask);
        max_sock = MAX(sss->sock, sss->mgmt_sock);

        FD_SET(sss->sock, &socket_mask);
        FD_SET(sss->mgmt_sock, &socket_mask);

        wait_time.tv_sec = 10;
        wait_time.tv_usec = 0;
        rc = select(max_sock + 1, &socket_mask, NULL, NULL, &wait_time);

        now = time(NULL);

        if (rc > 0)
        {
            if (FD_ISSET(sss->sock, &socket_mask))
            {
                struct sockaddr_in sender_sock;
                socklen_t i;

                i = sizeof(sender_sock);
                bread = recvfrom(sss->sock, pktbuf, N2N_SN_PKTBUF_SIZE, 0 /*flags*/,
                                 (struct sockaddr *)&sender_sock, (socklen_t *)&i);

                if ((bread < 0)
#ifdef WIN32
                    && (WSAGetLastError() != WSAECONNRESET)
#endif
                )
                {
                    /* For UDP bread of zero just means no data (unlike TCP). */
                    /* The fd is no good now. Maybe we lost our interface. */
                    traceEvent(TRACE_ERROR, "recvfrom() failed %d errno %d (%s)", bread, errno, strerror(errno));
#ifdef WIN32
                    traceEvent(TRACE_ERROR, "WSAGetLastError(): %u", WSAGetLastError());
#endif
                    keep_running = 0;
                    break;
                }

                /* We have a datagram to process */
                if (bread > 0)
                {
                    /* And the datagram has data (not just a header) */
                    process_udp(sss, &sender_sock, pktbuf, bread, now);
                }
            }

            if (FD_ISSET(sss->mgmt_sock, &socket_mask))
            {
                struct sockaddr_in sender_sock;
                size_t i;

                i = sizeof(sender_sock);
                bread = recvfrom(sss->mgmt_sock, pktbuf, N2N_SN_PKTBUF_SIZE, 0 /*flags*/,
                                 (struct sockaddr *)&sender_sock, (socklen_t *)&i);

                if (bread <= 0)
                {
                    traceEvent(TRACE_ERROR, "recvfrom() failed %d errno %d (%s)", bread, errno, strerror(errno));
                    keep_running = 0;
                    break;
                }

                /* We have a datagram to process */
                process_mgmt(sss, &sender_sock, pktbuf, bread, now);
            }
        }
        else
        {
            traceEvent(TRACE_DEBUG, "timeout");
        }

        HASH_ITER(hh, sss->communities, comm, tmp)
        {
            purge_expired_registrations(&comm->edges, &last_purge_edges);

            if ((comm->edges == NULL) && (!sss->lock_communities))
            {
                traceEvent(TRACE_INFO, "Purging idle community %s", comm->community);
                HASH_DEL(sss->communities, comm);
                free(comm);
            }
        }

    } /* while */

    sn_term(sss);

    return 0;
}