l2/connection: refactoring
- split handle_packet() in two functions: the first does basic checks and calls the second one. This allows to do the basic checks externally (in the multi-connection management module) without duplicating them. - use the new layer2_encode_packet() function.
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0345dc589b
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bfdb174324
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@ -80,19 +80,6 @@ result_t connection_handle_packet(connection_ctx_t *ctx, const uint8_t *buf, siz
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return OK;
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}
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if(!ham64_is_equal(&header.src_addr, &ctx->peer_addr)) {
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char fmt_src_addr[HAM64_FMT_MAX_LEN];
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char fmt_peer_addr[HAM64_FMT_MAX_LEN];
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ham64_format(&header.src_addr, fmt_src_addr);
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ham64_format(&ctx->peer_addr, fmt_peer_addr);
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LOG(LVL_ERR, "Packet has the wrong source address: got %s, expected %s",
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fmt_src_addr, fmt_peer_addr);
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return ERR_INVALID_ADDRESS;
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}
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if(!ham64_is_equal(&header.dst_addr, &ctx->my_addr)) {
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char fmt_dst_addr[HAM64_FMT_MAX_LEN];
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char fmt_my_addr[HAM64_FMT_MAX_LEN];
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@ -106,44 +93,85 @@ result_t connection_handle_packet(connection_ctx_t *ctx, const uint8_t *buf, siz
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return ERR_INVALID_ADDRESS;
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}
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size_t header_size = layer2_get_encoded_header_size(&header);
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const uint8_t *payload = buf + header_size;
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size_t payload_len = packet_size - header_size;
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return connection_handle_packet_prechecked(ctx, &header, payload, payload_len);
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}
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result_t connection_handle_packet_prechecked(
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connection_ctx_t *ctx,
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const layer2_packet_header_t *header,
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const uint8_t *payload, size_t payload_len)
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{
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// check the connection state
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switch(ctx->conn_state) {
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case CONN_STATE_UNINITIALIZED:
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case CONN_STATE_INITIALIZED:
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case CONN_STATE_CLOSED:
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LOG(LVL_ERR, "Trying to pass packet to connection in state %u", ctx->conn_state);
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return ERR_INVALID_STATE;
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case CONN_STATE_CONNECTING:
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case CONN_STATE_ESTABLISHED:
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// in these states, packets can be handled
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break;
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}
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// check if this packet is from our designated peer
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if(!ham64_is_equal(&header->src_addr, &ctx->peer_addr)) {
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char fmt_src_addr[HAM64_FMT_MAX_LEN];
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char fmt_peer_addr[HAM64_FMT_MAX_LEN];
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ham64_format(&header->src_addr, fmt_src_addr);
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ham64_format(&ctx->peer_addr, fmt_peer_addr);
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LOG(LVL_ERR, "Packet has the wrong source address: got %s, expected %s",
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fmt_src_addr, fmt_peer_addr);
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return ERR_INVALID_ADDRESS;
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}
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LOG(LVL_DEBUG, "Handling %s packet with rx_seq_nr %u, tx_seq_nr %u.",
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layer2_msg_type_to_string(header.msg_type), header.rx_seq_nr, header.tx_seq_nr);
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layer2_msg_type_to_string(header->msg_type), header->rx_seq_nr, header->tx_seq_nr);
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ctx->last_acked_seq = header.rx_seq_nr;
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ctx->last_acked_seq = header->rx_seq_nr;
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switch(header.msg_type) {
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switch(header->msg_type) {
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case L2_MSG_TYPE_EMPTY:
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LOG(LVL_DEBUG, "Empty packet: accepted ACK for %u.", ctx->last_acked_seq);
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// handle the acknowledgement internally
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connection_handle_ack(ctx, header.rx_seq_nr, false);
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connection_handle_ack(ctx, header->rx_seq_nr, false);
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return OK; // do not ACK and call back
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case L2_MSG_TYPE_CONN_MGMT:
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case L2_MSG_TYPE_CONNECTIONLESS:
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LOG(LVL_WARN, "Message type %s is not implemented yet.", layer2_msg_type_to_string(header.msg_type));
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LOG(LVL_WARN, "Message type %s is not implemented yet.", layer2_msg_type_to_string(header->msg_type));
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return OK;
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case L2_MSG_TYPE_DATA:
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break;
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default:
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LOG(LVL_ERR, "Invalid message type %d.", header.msg_type);
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LOG(LVL_ERR, "Invalid message type %d.", header->msg_type);
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return ERR_INVALID_STATE;
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}
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if(ctx->next_expected_seq != header.tx_seq_nr) {
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LOG(LVL_ERR, "Expected sequence number %u, received %u.", ctx->next_expected_seq, header.tx_seq_nr);
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if(ctx->next_expected_seq != header->tx_seq_nr) {
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LOG(LVL_ERR, "Expected sequence number %u, received %u.", ctx->next_expected_seq, header->tx_seq_nr);
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return ERR_SEQUENCE;
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}
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ctx->next_expected_seq++;
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ctx->next_expected_seq &= 0xF;
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LOG(LVL_INFO, "Received ACK for seq_nr %u in packet seq_nr %u.", header.rx_seq_nr, header.tx_seq_nr);
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LOG(LVL_INFO, "Received ACK for seq_nr %u in packet seq_nr %u.", header->rx_seq_nr, header->tx_seq_nr);
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// handle the acknowledgement internally
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connection_handle_ack(ctx, header.rx_seq_nr, true);
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connection_handle_ack(ctx, header->rx_seq_nr, true);
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size_t header_size = layer2_get_encoded_header_size(&header);
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@ -267,7 +295,7 @@ size_t connection_encode_next_packet(connection_ctx_t *ctx, uint8_t ack_seq_nr,
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case CONN_STATE_INITIALIZED:
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case CONN_STATE_CLOSED:
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LOG(LVL_ERR, "Trying to encode packet in inactive state %u", ctx->conn_state);
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return ERR_INVALID_STATE;
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return 0;
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case CONN_STATE_CONNECTING:
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case CONN_STATE_ESTABLISHED:
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@ -282,30 +310,18 @@ size_t connection_encode_next_packet(connection_ctx_t *ctx, uint8_t ack_seq_nr,
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return 0;
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}
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unsigned int crc_size = crc_sizeof_key(PAYLOAD_CRC_SCHEME);
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assert(buf_len >= LAYER2_PACKET_HEADER_ENCODED_SIZE_MAX + crc_size + entry->data_len);
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layer2_packet_header_t header = entry->header;
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header.rx_seq_nr = ack_seq_nr;
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// encode the header
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LOG(LVL_DEBUG, "Encoding packet with rx_seq_nr %u, tx_seq_nr %u.", header.rx_seq_nr, header.tx_seq_nr);
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size_t packet_size = layer2_encode_packet_header(&header, buf);
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// add the payload data
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if(entry->data) {
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memcpy(buf + packet_size, entry->data, entry->data_len);
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size_t packet_size = layer2_encode_packet(&header, entry->data, entry->data_len, buf, buf_len);
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if(packet_size == 0) {
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LOG(LVL_ERR, "Buffer too small for encoded packet!");
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return 0;
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}
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packet_size += entry->data_len;
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// calculate CRC of everything and append it to the packet
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crc_append_key(PAYLOAD_CRC_SCHEME, buf, packet_size);
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packet_size += crc_size;
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ctx->next_packet_index++;
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return packet_size;
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@ -71,6 +71,24 @@ void connection_destroy(connection_ctx_t *ctx);
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*/
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result_t connection_handle_packet(connection_ctx_t *ctx, const uint8_t *buf, size_t buf_len);
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/*!\brief Handle a received packet where the header has already been decoded.
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*
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* This function assumes that the following basic checks were already done:
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* - CRC is correct
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* - Header can be decoded
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* - Destination address is the local address
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*
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* \param ctx The connection context.
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* \param header Pointer to the decoded header structure.
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* \param payload Pointer to the payload data.
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* \param payload_len Length of the payload data.
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* \returns A result code from the packet handling procedure.
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*/
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result_t connection_handle_packet_prechecked(
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connection_ctx_t *ctx,
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const layer2_packet_header_t *header,
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const uint8_t *payload, size_t payload_len);
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/*!\brief Return the sequence number expected next by our side.
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*/
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uint8_t connection_get_next_expected_seq(const connection_ctx_t *ctx);
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