t_header parser_header(t_line **file, int comment, int name)
{
t_header result;
int line;
line = 0;
result.prog_size = (*file)->size;
result.magic = COREWAR_EXEC_MAGIC;
while (++line && token_header((*file)->line->token))
{
if ((*file)->line->token == COMMAND_NAME && name--)
parser_name(result.name, (*file));
else if ((*file)->line->token == COMMAND_COMMENT && comment--)
parser_comment(result.comment, (*file));
else if ((*file)->line->token != ENDLINE)
print_error_token((*file), (*file)->line, SYNTAX_MSG);
(*file) = (*file)->next;
}
if (name || comment)
print_error_token((*file), (*file)->line, SYNTAX_MSG);
(*file) = delete_header((*file)->start, line);
return (result);
}
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;
}