コード例 #1
0
ファイル: udp.c プロジェクト: IAmAnubhavSaini/junkie
static enum proto_parse_status udp_parse(struct parser *parser, struct proto_info *parent, unsigned way, uint8_t const *packet, size_t cap_len, size_t wire_len, struct timeval const *now, size_t tot_cap_len, uint8_t const *tot_packet)
{
    struct mux_parser *mux_parser = DOWNCAST(parser, parser, mux_parser);
    struct udp_hdr const *udphdr = (struct udp_hdr *)packet;

    // Sanity checks
    if (wire_len < sizeof(*udphdr)) {
        SLOG(LOG_DEBUG, "Bogus UDP packet: too short (%zu < %zu)", wire_len, sizeof(*udphdr));
        return PROTO_PARSE_ERR;
    }

    if (cap_len < sizeof(*udphdr)) return PROTO_TOO_SHORT;

    size_t tot_len = READ_U16N(&udphdr->len);
    if (tot_len < sizeof(*udphdr)) {
        SLOG(LOG_DEBUG, "Bogus UDP packet: UDP tot len shorter than UDP header (%zu < %zu)", tot_len, sizeof(*udphdr));
        return PROTO_PARSE_ERR;
    }

    size_t payload = tot_len - sizeof(*udphdr);
    if (payload > wire_len) {
        SLOG(LOG_DEBUG, "Bogus UDP packet: wrong length %zu > %zu", payload, wire_len);
        return PROTO_PARSE_ERR;
    }

    uint16_t const sport = READ_U16N(&udphdr->src);
    uint16_t const dport = READ_U16N(&udphdr->dst);
    SLOG(LOG_DEBUG, "New UDP packet of %zu bytes (%zu captured), ports %"PRIu16" -> %"PRIu16, wire_len, cap_len, sport, dport);

    // Parse

    struct udp_proto_info info;
    udp_proto_info_ctor(&info, parser, parent, sizeof(*udphdr), payload, sport, dport);

    // Search an already spawned subparser
    struct port_key key;
    port_key_init(&key, sport, dport, way);
    struct mux_subparser *subparser = mux_subparser_lookup(mux_parser, NULL, NULL, &key, now);
    if (subparser) SLOG(LOG_DEBUG, "Found subparser for this cnx, for proto %s", subparser->parser->proto->name);

    if (! subparser) {
        struct proto *requestor = NULL;
        struct proto *sub_proto = NULL;
        // Use connection tracking first
        ASSIGN_INFO_OPT2(ip, ip6, parent);
        if (! ip) ip = ip6;
        if (ip) sub_proto = cnxtrack_ip_lookup(IPPROTO_UDP, ip->key.addr+0, sport, ip->key.addr+1, dport, now, &requestor);
        if (! sub_proto) { // Then try predefined ports first
            sub_proto = port_muxer_find(&udp_port_muxers, info.key.port[0], info.key.port[1]);
        }
        if (sub_proto) subparser = mux_subparser_and_parser_new(mux_parser, sub_proto, requestor, &key, now);
    }

    if (! subparser) goto fallback;

    enum proto_parse_status status = proto_parse(subparser->parser, &info.info, way, packet + sizeof(*udphdr), cap_len - sizeof(*udphdr), wire_len - sizeof(*udphdr), now, tot_cap_len, tot_packet);
    if (status == PROTO_PARSE_ERR) {
        SLOG(LOG_DEBUG, "No suitable subparser for this payload");
        mux_subparser_deindex(subparser);
    }
    mux_subparser_unref(&subparser);
    if (status == PROTO_OK) return PROTO_OK;

fallback:
    (void)proto_parse(NULL, &info.info, way, packet + sizeof(*udphdr), cap_len - sizeof(*udphdr), wire_len - sizeof(*udphdr), now, tot_cap_len, tot_packet);
    return PROTO_OK;
}
コード例 #2
0
ファイル: tcp.c プロジェクト: Mybrc91/junkie
static enum proto_parse_status tcp_parse(struct parser *parser, struct proto_info *parent, unsigned way, uint8_t const *packet, size_t cap_len, size_t wire_len, struct timeval const *now, size_t tot_cap_len, uint8_t const *tot_packet)
{
    struct mux_parser *mux_parser = DOWNCAST(parser, parser, mux_parser);
    struct tcp_hdr const *tcphdr = (struct tcp_hdr *)packet;

    // Sanity checks
    if (wire_len < sizeof(*tcphdr)) {
        SLOG(LOG_DEBUG, "Bogus TCP packet: too short (%zu < %zu)", wire_len, sizeof(*tcphdr));
        return PROTO_PARSE_ERR;
    }

    if (cap_len < sizeof(*tcphdr)) return PROTO_TOO_SHORT;

    size_t tcphdr_len = TCP_HDR_LENGTH(tcphdr);

    if (tcphdr_len < sizeof(*tcphdr)) {
        SLOG(LOG_DEBUG, "Bogus TCP packet: header size too smal (%zu < %zu)", tcphdr_len, sizeof(*tcphdr));
        return PROTO_PARSE_ERR;
    }

    if (tcphdr_len > wire_len) {
        SLOG(LOG_DEBUG, "Bogus TCP packet: wrong length %zu > %zu", tcphdr_len, wire_len);
        return PROTO_PARSE_ERR;
    }

    if (tcphdr_len > cap_len) return PROTO_TOO_SHORT;

    // TODO: move this below call to tcp_proto_info_ctor() and use info instead of reading tcphdr directly
    uint16_t const sport = READ_U16N(&tcphdr->src);
    uint16_t const dport = READ_U16N(&tcphdr->dst);
    bool const syn = !!(READ_U8(&tcphdr->flags) & TCP_SYN_MASK);
    bool const fin = !!(READ_U8(&tcphdr->flags) & TCP_FIN_MASK);
    bool const ack = !!(READ_U8(&tcphdr->flags) & TCP_ACK_MASK);
    bool const rst = !!(READ_U8(&tcphdr->flags) & TCP_RST_MASK);
    bool const urg = !!(READ_U8(&tcphdr->flags) & TCP_URG_MASK);
    bool const psh = !!(READ_U8(&tcphdr->flags) & TCP_PSH_MASK);
    SLOG(LOG_DEBUG, "New TCP packet of %zu bytes (%zu captured), %zu payload, ports %"PRIu16" -> %"PRIu16" Flags: %s%s%s%s%s%s, Seq:%"PRIu32", Ack:%"PRIu32,
        wire_len, cap_len, wire_len - tcphdr_len, sport, dport,
        syn ? "Syn":"", fin ? "Fin":"", ack ? "Ack":"", rst ? "Rst":"", urg ? "Urg":"", psh ? "Psh":"",
        READ_U32N(&tcphdr->seq_num), READ_U32N(&tcphdr->ack_seq));

    // Parse

    struct tcp_proto_info info;
    tcp_proto_info_ctor(&info, parser, parent, tcphdr_len, wire_len - tcphdr_len, sport, dport, tcphdr);

    // Parse TCP options
    uint8_t const *options = (uint8_t *)(tcphdr+1);
    assert(tcphdr_len >= sizeof(*tcphdr));
    for (size_t rem_len = tcphdr_len - sizeof(*tcphdr); rem_len > 0; ) {
        ssize_t const len = parse_next_option(&info, options, rem_len);
        if (len < 0) return PROTO_PARSE_ERR;
        rem_len -= len;
        options += len;
    }

    // Search an already spawned subparser
    struct port_key key;
    port_key_init(&key, sport, dport, way);
    struct mux_subparser *subparser = mux_subparser_lookup(mux_parser, NULL, NULL, &key, now);
    if (subparser) SLOG(LOG_DEBUG, "Found subparser@%p for this cnx, for proto %s", subparser->parser, subparser->parser->proto->name);

    if (! subparser) {
        struct proto *requestor = NULL;
        struct proto *sub_proto = NULL;
        // Use connection tracking first
        ASSIGN_INFO_OPT2(ip, ip6, parent);
        if (! ip) ip = ip6;
        if (ip) sub_proto = cnxtrack_ip_lookup(IPPROTO_TCP, ip->key.addr+0, sport, ip->key.addr+1, dport, now, &requestor);
        if (! sub_proto) { // Then try predefined ports
            sub_proto = port_muxer_find(&tcp_port_muxers, info.key.port[0], info.key.port[1]);
        }
        if (sub_proto) {
            subparser = mux_subparser_and_parser_new(mux_parser, sub_proto, requestor, &key, now);
        } else {
            // Even if we have no child parser to send payload to, we want to submit payload in stream order to our plugins
            subparser = tcp_subparser_new(mux_parser, NULL, NULL, &key, now);
        }
    }

    if (! subparser) goto fallback;

    // Keep track of TCP flags & ISN
    struct tcp_subparser *tcp_sub = DOWNCAST(subparser, mux_subparser, tcp_subparser);
    mutex_lock(tcp_sub->mutex);
    if (
        info.ack &&
        (!IS_SET_FOR_WAY(way, tcp_sub->ack) || seqnum_gt(info.ack_num, tcp_sub->max_acknum[way]))
    ) {
        SET_FOR_WAY(way, tcp_sub->ack);
        tcp_sub->max_acknum[way] = info.ack_num;
    }
    if (info.fin) {
        SET_FOR_WAY(way, tcp_sub->fin);
        tcp_sub->fin_seqnum[way] = info.seq_num + info.info.payload;    // The FIN is acked after the payload
    }
    if (info.syn && !IS_SET_FOR_WAY(way, tcp_sub->syn)) {
        SET_FOR_WAY(way, tcp_sub->syn);
        tcp_sub->isn[way] = info.seq_num;
    }
    if (!IS_SET_FOR_WAY(way, tcp_sub->origin)) {
        SET_FOR_WAY(way, tcp_sub->origin);
        tcp_sub->wl_origin[way] = info.seq_num;
        if (! IS_SET_FOR_WAY(way, tcp_sub->syn)) SLOG(LOG_DEBUG, "Starting a WL while SYN is yet to be received!");
    }

    // Set relative sequence number if we know it
    if (IS_SET_FOR_WAY(way, tcp_sub->syn)) info.rel_seq_num = info.seq_num - tcp_sub->isn[way];

    // Set srv_way
    assert(tcp_sub->srv_set < 3);
    if (tcp_sub->srv_set == 0 || (tcp_sub->srv_set == 1 && info.syn)) {
        if (comes_from_client(info.key.port, info.syn, info.ack)) {
            // this packet comes from the client
            tcp_sub->srv_way = !way;
        } else {
            tcp_sub->srv_way = way;
        }
        tcp_sub->srv_set = info.syn ? 2:1;
    }
    // Now patch it into tcp info
    info.to_srv = tcp_sub->srv_way != way;

    SLOG(LOG_DEBUG, "Subparser@%p state: >ISN:%"PRIu32"%s Fin:%"PRIu32" Ack:%"PRIu32" <ISN:%"PRIu32"%s Fin:%"PRIu32" Ack:%"PRIu32", SrvWay=%u%s",
        subparser->parser,
        IS_SET_FOR_WAY(0, tcp_sub->syn) ? tcp_sub->isn[0] : IS_SET_FOR_WAY(0, tcp_sub->origin) ? tcp_sub->wl_origin[0] : 0,
        IS_SET_FOR_WAY(0, tcp_sub->syn) ? "" : " (approx)",
        IS_SET_FOR_WAY(0, tcp_sub->fin) ? tcp_sub->fin_seqnum[0] : 0,
        IS_SET_FOR_WAY(0, tcp_sub->ack) ? tcp_sub->max_acknum[0] : 0,
        IS_SET_FOR_WAY(1, tcp_sub->syn) ? tcp_sub->isn[1] : IS_SET_FOR_WAY(1, tcp_sub->origin) ? tcp_sub->wl_origin[1] : 0,
        IS_SET_FOR_WAY(1, tcp_sub->syn) ? "" : " (approx)",
        IS_SET_FOR_WAY(1, tcp_sub->fin) ? tcp_sub->fin_seqnum[1] : 0,
        IS_SET_FOR_WAY(1, tcp_sub->ack) ? tcp_sub->max_acknum[1] : 0,
        tcp_sub->srv_way,
        tcp_sub->srv_set == 0 ? " (unset)":
            tcp_sub->srv_set == 1 ? " (unsure)":"(certain)");

    enum proto_parse_status err;
    /* Use the wait_list to parse this packet.
       Notice that we do queue empty packets because subparser (or subscriber) want to receive all packets in order, including empty ones. */

    size_t const packet_len = wire_len - tcphdr_len;
    assert(IS_SET_FOR_WAY(way, tcp_sub->origin));
    unsigned const offset = info.seq_num - tcp_sub->wl_origin[way];
    unsigned const next_offset = offset + packet_len + info.syn + info.fin;
    unsigned const sync_offset = info.ack_num - tcp_sub->wl_origin[!way];  // we must not parse this one before we parsed (or timeouted) this one from wl[!way]
    // FIXME: Here the parser is chosen before we actually parse anything. If later the parser fails we cannot try another one.
    //        Choice of parser should be delayed until we start actual parse.
    bool const do_sync = info.ack && IS_SET_FOR_WAY(!way, tcp_sub->origin);
    err = pkt_wait_list_add(tcp_sub->wl+way, offset, next_offset, do_sync, sync_offset, true, &info.info, way, packet + tcphdr_len, cap_len - tcphdr_len, packet_len, now, tot_cap_len, tot_packet);
    SLOG(LOG_DEBUG, "Waiting list returned %s", proto_parse_status_2_str(err));

    if (err == PROTO_OK) {
        // Try advancing each WL until we are stuck or met an error
        pkt_wait_list_try_both(tcp_sub->wl+!way, &err, now, false);
    }

    bool const term = tcp_subparser_term(tcp_sub);
    mutex_unlock(tcp_sub->mutex);

    if (term || err == PROTO_PARSE_ERR) {
        if (term) {
            SLOG(LOG_DEBUG, "TCP cnx terminated (was %s)", parser_name(subparser->parser));
        } else {
            SLOG(LOG_DEBUG, "No suitable subparser for this payload");
        }
        mux_subparser_deindex(subparser);
    }
    mux_subparser_unref(&subparser);

    if (err == PROTO_OK) return PROTO_OK;

fallback:
    (void)proto_parse(NULL, &info.info, way, packet + tcphdr_len, cap_len - tcphdr_len, wire_len - tcphdr_len, now, tot_cap_len, tot_packet);
    return PROTO_OK;
}