Danielle Ratson wrote: > RFC 4884 extended certain ICMP messages with a length attribute that > encodes the length of the "original datagram" field. This is needed so > that new information could be appended to these messages without > applications thinking that it is part of the "original datagram" field. > > In version 5.9, the kernel was extended with two new socket options > (SOL_IP/IP_RECVERR_4884 and SOL_IPV6/IPV6_RECVERR_RFC4884) that allow > user space to retrieve this length which is basically the offset to the > ICMP Extension Structure at the end of the ICMP message. This is > required by user space applications that need to parse the information > contained in the ICMP Extension Structure. For example, the RFC 5837 > extension for tracepath. > > Add a selftest that verifies correct handling of the RFC 4884 length > field for both IPv4 and IPv6, with and without extension structures, > and validates that malformed extensions are correctly reported as invalid. > > For each address family, the test creates: > - a raw socket used to send locally crafted ICMP error packets to the > loopback address, and > - a datagram socket used to receive the encapsulated original datagram > and associated error metadata from the kernel error queue. > > ICMP packets are constructed entirely in user space rather than relying > on kernel-generated errors. This allows the test to exercise invalid > scenarios (such as corrupted checksums and incorrect length fields) and > verify that the SO_EE_RFC4884_FLAG_INVALID flag is set as expected. > > Output Example: > > $ ./icmp_rfc4884 > Starting 18 tests from 18 test cases. > RUN rfc4884.ipv4_ext_small_payload.rfc4884 ... > OK rfc4884.ipv4_ext_small_payload.rfc4884 > ok 1 rfc4884.ipv4_ext_small_payload.rfc4884 > RUN rfc4884.ipv4_ext.rfc4884 ... > OK rfc4884.ipv4_ext.rfc4884 > ok 2 rfc4884.ipv4_ext.rfc4884 > RUN rfc4884.ipv4_ext_large_payload.rfc4884 ... > OK rfc4884.ipv4_ext_large_payload.rfc4884 > ok 3 rfc4884.ipv4_ext_large_payload.rfc4884 > RUN rfc4884.ipv4_no_ext_small_payload.rfc4884 ... > OK rfc4884.ipv4_no_ext_small_payload.rfc4884 > ok 4 rfc4884.ipv4_no_ext_small_payload.rfc4884 > RUN rfc4884.ipv4_no_ext_min_payload.rfc4884 ... > OK rfc4884.ipv4_no_ext_min_payload.rfc4884 > ok 5 rfc4884.ipv4_no_ext_min_payload.rfc4884 > RUN rfc4884.ipv4_no_ext_large_payload.rfc4884 ... > OK rfc4884.ipv4_no_ext_large_payload.rfc4884 > ok 6 rfc4884.ipv4_no_ext_large_payload.rfc4884 > RUN rfc4884.ipv4_invalid_ext_checksum.rfc4884 ... > OK rfc4884.ipv4_invalid_ext_checksum.rfc4884 > ok 7 rfc4884.ipv4_invalid_ext_checksum.rfc4884 > RUN rfc4884.ipv4_invalid_ext_length_small.rfc4884 ... > OK rfc4884.ipv4_invalid_ext_length_small.rfc4884 > ok 8 rfc4884.ipv4_invalid_ext_length_small.rfc4884 > RUN rfc4884.ipv4_invalid_ext_length_large.rfc4884 ... > OK rfc4884.ipv4_invalid_ext_length_large.rfc4884 > ok 9 rfc4884.ipv4_invalid_ext_length_large.rfc4884 > RUN rfc4884.ipv6_ext_small_payload.rfc4884 ... > OK rfc4884.ipv6_ext_small_payload.rfc4884 > ok 10 rfc4884.ipv6_ext_small_payload.rfc4884 > RUN rfc4884.ipv6_ext.rfc4884 ... > OK rfc4884.ipv6_ext.rfc4884 > ok 11 rfc4884.ipv6_ext.rfc4884 > RUN rfc4884.ipv6_ext_large_payload.rfc4884 ... > OK rfc4884.ipv6_ext_large_payload.rfc4884 > ok 12 rfc4884.ipv6_ext_large_payload.rfc4884 > RUN rfc4884.ipv6_no_ext_small_payload.rfc4884 ... > OK rfc4884.ipv6_no_ext_small_payload.rfc4884 > ok 13 rfc4884.ipv6_no_ext_small_payload.rfc4884 > RUN rfc4884.ipv6_no_ext_min_payload.rfc4884 ... > OK rfc4884.ipv6_no_ext_min_payload.rfc4884 > ok 14 rfc4884.ipv6_no_ext_min_payload.rfc4884 > RUN rfc4884.ipv6_no_ext_large_payload.rfc4884 ... > OK rfc4884.ipv6_no_ext_large_payload.rfc4884 > ok 15 rfc4884.ipv6_no_ext_large_payload.rfc4884 > RUN rfc4884.ipv6_invalid_ext_checksum.rfc4884 ... > OK rfc4884.ipv6_invalid_ext_checksum.rfc4884 > ok 16 rfc4884.ipv6_invalid_ext_checksum.rfc4884 > RUN rfc4884.ipv6_invalid_ext_length_small.rfc4884 ... > OK rfc4884.ipv6_invalid_ext_length_small.rfc4884 > ok 17 rfc4884.ipv6_invalid_ext_length_small.rfc4884 > RUN rfc4884.ipv6_invalid_ext_length_large.rfc4884 ... > OK rfc4884.ipv6_invalid_ext_length_large.rfc4884 > ok 18 rfc4884.ipv6_invalid_ext_length_large.rfc4884 > PASSED: 18 / 18 tests passed. > Totals: pass:18 fail:0 xfail:0 xpass:0 skip:0 error:0 > > Signed-off-by: Danielle Ratson <[email protected]> > Reviewed-by: Ido Schimmel <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]> Thanks!
