IP Checksum Extern Function

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IP Checksum Extern

Description - compute the IP checksum on the given IP header. Does not currently support IP headers with options. This function will set the provided hdrChecksum field to 0 while it is computing the result.

Instantiation:

@Xilinx_MaxLatency(3)
@Xilinx_ControlWidth(0)
extern void <name>_ip_chksum(in bit<4> version, 
                         in bit<4> ihl,
                         in bit<8> tos,
                         in bit<16> totalLen,
                         in bit<16> identification,
                         in bit<3> flags,
                         in bit<13> fragOffset,
                         in bit<8> ttl,
                         in bit<8> protocol,
                         in bit<16> hdrChecksum,
                         in bit<32> srcAddr,
                         in bit<32> dstAddr,
                         out bit<16> result);

• result - the resulting checksum value