Contiki-NG
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Functions | |
void | uip_add32 (uint8_t *op32, uint16_t op16) |
Carry out a 32-bit addition. | |
uint16_t | uip_ipchksum (void) |
Calculate the IP header checksum of the packet header in uip_buf. | |
uint16_t | uip_tcpchksum (void) |
Calculate the TCP checksum of the packet in uip_buf and uip_appdata. | |
Variables | |
uint8_t | uip_acc32 [4] |
4-byte array used for the 32-bit sequence number calculations. | |
The functions in the architecture specific module implement the IP check sum and 32-bit additions.
The IP checksum calculation is the most computationally expensive operation in the TCP/IP stack and it therefore pays off to implement this in efficient assembler. The purpose of the uip-arch module is to let the checksum functions to be implemented in architecture specific assembler.
void uip_add32 | ( | uint8_t * | op32, |
uint16_t | op16 ) |
Carry out a 32-bit addition.
Because not all architectures for which uIP is intended has native 32-bit arithmetic, uIP uses an external C function for doing the required 32-bit additions in the TCP protocol processing. This function should add the two arguments and place the result in the global variable uip_acc32.
op32 | A pointer to a 4-byte array representing a 32-bit integer in network byte order (big endian). |
op16 | A 16-bit integer in host byte order. |
Definition at line 252 of file uip6.c.
References uip_acc32.
uint16_t uip_ipchksum | ( | void | ) |
Calculate the IP header checksum of the packet header in uip_buf.
The IP header checksum is the Internet checksum of the 20 bytes of the IP header.
Definition at line 320 of file uip6.c.
References uip_buf, and uip_htons().
uint16_t uip_tcpchksum | ( | void | ) |
Calculate the TCP checksum of the packet in uip_buf and uip_appdata.
The TCP checksum is the Internet checksum of data contents of the TCP segment, and a pseudo-header as defined in RFC793.