Bad system of dropping packets

[xbrakl]

This code checks the checksum of the packet in both ingress as well as egress parser, but doesn't store result of the checksum verification into a value in user-defined metadata (out metadata meta parameter of both parsers). As a result of this mistake, both ingress and egress control have no idea, that they should change the value of drop_ctl parameter which indicates when packet should be dropped.

Possible solution:
structure (out metadata meta) should have parameter something like bool checksum_error which ingress and egress control can analyze and set the proper value of the ingress deparser metadata parameter drop_ctl so then deparser can drop the packet based on the value of this parameter drop_ctl.

Also code of both ingress and egress deparsers is not checking this parameter drop_ctl and is not droping packets when this parameter indicates, that packet should be dropped.

int-platforms/p4src/int_v1.0/include/parser.p4

Lines 77 to 82 in aa0b7be

	#ifdef TOFINO
	ipv4_checksum.add(hdr.ipv4);
	/*// Output of verify is 0 or 1*/
	/*// If it is 1, there is checksum error*/
	ipv4_checksum.verify();
	#endif

int-platforms/p4src/int_v1.0/include/parser.p4

Lines 307 to 310 in aa0b7be

	ipv4_checksum.add(hdr.ipv4);
	/*// Output of verify is 0 or 1*/
	/*// If it is 1, there is checksum error*/
	ipv4_checksum.verify();