net/gnrc/transport_layer/tcp/internal/pkt.h

TCP paket handling declarations.

int _pkt_build_reset_from_pkt(include/net/gnrc/pkt.h::gnrc_pktsnip_t ** out_pkt, include/net/gnrc/pkt.h::gnrc_pktsnip_t * in_pkt)

Build a reset packet from an incomming packet.

Note

This function builds a reset from an incomming packet in cases where the connection has not been established.

Parameters

out_pkt:Outgoing reset packet
in_pkt:Incomming packet

Return values

  • Zero on success -ENOMEM if pktbuf is full.
int _pkt_build(tcb.h::gnrc_tcp_tcb_t * tcb, include/net/gnrc/pkt.h::gnrc_pktsnip_t ** out_pkt, uint16_t * seq_con, const uint16_t ctl, const uint32_t seq_num, const uint32_t ack_num, void * payload, const msp430_types.h::size_t payload_len)

Build and allocate a TCB paket, TCB stores pointer to new paket.

Parameters

tcb:TCB holding the connection information.
out_pkt:Pointer to paket to build.
seq_con:Sequence number consumption of built packet.
ctl:Control bits to set in out_pkt.
seq_num:Sequence number of the new packet.
ack_num:Acknowledgment number of the new packet.
payload:Pointer to payload buffer.
payload_len:Payload size.

Return values

  • Zero on success. -ENOMEM if pktbuf is full.
int _pkt_send(tcb.h::gnrc_tcp_tcb_t * tcb, include/net/gnrc/pkt.h::gnrc_pktsnip_t * out_pkt, const uint16_t seq_con, const bool retransmit)

Sends packet to peer.

Parameters

tcb:TCB holding the connection information.
out_pkt:Pointer to paket to send.
seq_con:Sequence number consumption of the packet to send.
retransmit:Flag so mark that packet this is a retransmission.

Return values

  • Zero on success. -EINVAL if out_pkt was NULL.
int _pkt_chk_seq_num(const tcb.h::gnrc_tcp_tcb_t * tcb, const uint32_t seq_num, const uint32_t seg_len)

Verify sequence number.

Parameters

tcb:TCB holding the connection information.
seq_num:Sequence number from the segment.
seg_len:Length of a segments payload.

Return values

  • Zero if the sequence number is acceptable. Negative value if the sequence number is not acceptable.
uint32_t _pkt_get_seg_len(include/net/gnrc/pkt.h::gnrc_pktsnip_t * pkt)

Extracts the length of a segment.

Parameters

pkt:Packet to calculate the segments length.

Return values

  • Segments length in bytes (== sequence number consumption).
uint32_t _pkt_get_pay_len(include/net/gnrc/pkt.h::gnrc_pktsnip_t * pkt)

Calculates a packets payload length.

Parameters

pkt:Packet to calculate payload length.

Return values

  • The packets payload length in bytes.
int _pkt_setup_retransmit(tcb.h::gnrc_tcp_tcb_t * tcb, include/net/gnrc/pkt.h::gnrc_pktsnip_t * pkt, const bool retransmit)

Adds a packet to the retransmission mechanism.

Parameters

tcb:TCB holding the connection information.
pkt:Packet to add to the retransmission mechanism.
retransmit:Flag used to indicate that pkt is a retransmit.

Return values

  • Zero on success. -ENOMEM if the retransmission queue is full. -EINVAL if pkt is null.
int _pkt_acknowledge(tcb.h::gnrc_tcp_tcb_t * tcb, const uint32_t ack)

Acknowledges and removes packet from the retransmission mechanism.

Parameters

tcb:TCB holding the connection information.
ack:Acknowldegment number used to acknowledge packets.

Return values

  • Zero on success. -ENODATA if there is nothing to acknowledge.
uint16_t _pkt_calc_csum(const include/net/gnrc/pkt.h::gnrc_pktsnip_t * hdr, const include/net/gnrc/pkt.h::gnrc_pktsnip_t * pseudo_hdr, const include/net/gnrc/pkt.h::gnrc_pktsnip_t * payload)

Calculates checksum over payload, TCP header and network layer header.

Parameters

hdr:Gnrc_pktsnip_t to TCP header.
pseudo_hdr:Gnrc_pktsnip_t to network layer header.
payload:Gnrc_pktsnip_t to payload.

Return values

  • Non-zero checksum if given network layer is supported. Zero if given network layer is not supported.