86 lines
No EOL
3.2 KiB
Text
86 lines
No EOL
3.2 KiB
Text
#ifndef NICO_DELTA_CHECKSUM
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#define NICO_DELTA_CHECKSUM
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action v4sum() {
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bit<32> tmp = 0;
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bit<32> carryover = 0;
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tmp = tmp + (bit<32>) hdr.ipv4.src_addr[15:0]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv4.src_addr[31:16]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv4.dst_addr[15:0]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv4.dst_addr[31:16]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv4.totalLen -20; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv4.protocol; // 8 bit
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carryover = tmp >> 16; /* maximum is 6*(2**16) >> 16 == 6 */
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tmp = (tmp & 0xffff) + carryover; /* Now tmp contains at maximum 65541 */
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carryover = tmp >> 16; /* Now carryover contains at maximum 1 */
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tmp = (tmp & 0xffff) + carryover; /* No overrun possible anymore */
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meta.v4sum = (bit<16>) tmp;
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}
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action v6sum() {
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bit<32> tmp = 0;
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bit<32> carryover = 0;
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[15:0]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[31:16]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[47:32]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[63:48]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[79:64]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[95:80]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[111:96]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.src_addr[127:112]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[15:0]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[31:16]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[47:32]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[63:48]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[79:64]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[95:80]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[111:96]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.dst_addr[127:112]; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.payload_length; // 16 bit
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tmp = tmp + (bit<32>) hdr.ipv6.next_header; // 8 bit
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carryover = tmp >> 16; /* maximum is 18*(2**16) >> 16 == 18 */
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tmp = (tmp & 0xffff) + carryover; /* Now tmp contains at maximum 65554*/
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carryover = tmp >> 16; /* Now carryover contains at maximum 1 */
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tmp = (tmp & 0xffff) + carryover; /* No overrun possible anymore */
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meta.v6sum = (bit<16>) tmp;
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}
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action delta_prepare()
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{
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v4sum();
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v6sum();
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if(meta.v6sum > meta.v4sum) {
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meta.headerdiff = meta.v6sum - meta.v4sum;
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} else {
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meta.headerdiff = meta.v4sum - meta.v6sum;
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}
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}
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action delta_udp_from_v4_to_v6()
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{
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delta_prepare();
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hdr.udp.checksum = hdr.udp.checksum + ~meta.headerdiff +1;
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}
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action delta_tcp_from_v4_to_v6()
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{
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delta_prepare();
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hdr.tcp.checksum = hdr.tcp.checksum + ~meta.headerdiff +1;
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}
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action delta_ipv4_from_v6_to_v4()
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{
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delta_prepare();
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hdr.tcp.checksum = hdr.tcp.checksum + ~meta.headerdiff;
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}
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#endif |