When receiving an ICMPv4 message containing extensions as defined in RFC 4884, and translating it to ICMPv6 at SIT or GRE tunnel, we need some extra manipulation in order to properly forward the extensions. This patch only takes care of Time Exceeded messages as they are the ones that typically carry information from various routers in a fabric during a traceroute session. It also avoids complex skb logic if the data_len is not a multiple of 8. RFC states : The "original datagram" field MUST contain at least 128 octets. If the original datagram did not contain 128 octets, the "original datagram" field MUST be zero padded to 128 octets. In practice routers use 128 bytes of original datagram, not more. Initial translation was added in commit ca15a078bd90 ("sit: generate icmpv6 error when receiving icmpv4 error")
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| @@ -79,6 +79,7 @@ struct icmphdr { · 78 unmodified lines | |||
| 79 | __be16 __unused; | 79 | __be16 __unused; |
| 80 | __be16 mtu; | 80 | __be16 mtu; |
| 81 | } frag; | 81 | } frag; |
| 82 | __u8 reserved[4]; | ||
| 82 | } un; | 83 | } un; |
| 83 | }; | 84 | }; |
| 84 | 85 | ||