commit ebd23f8b4b6645821a91bf9da4a10b3d30a98fb2
author Carlos Hernandez <carlos@hrndz.ca> Tue Feb 04 18:55:05 2025 +0000
committer Gopher Robot <gobot@golang.org> Tue Feb 04 14:06:08 2025 -0800
tree c73ea008686de998f722ab672b894c66bd135ccc
parent 938a9fb94e41285a443b0882dbc46f2a4c6ed484

route: fix parsing network address of length zero

sa_len of 0 should be valid, for Chapter 18 of UNIX® Network Programming
Volume 1, Third Edition: The Sockets Networking API, states:

The socket address structures are variable-length, but this code assumes
that each has an sa_len field specifying its length. There are two
complications that must be handled. First, the two masks, the network
mask and the cloning mask, can be returned in a socket address structure
with an sa_len of 0, but this really occupies the size of an unsigned
long. (Chapter 19 of TCPv2 discusses the cloning feature of the 4.4BSD
routing table). This value represents a mask of all zero bits, which we
printed as 0.0.0.0 for the network mask of the default route in our
earlier example.

There are other references in the book which also state sa_len of 0 is
valid.

Fixes golang/go#70528

Change-Id: I9205a674f9cdf8091b1cc8b8a56609cd1cf4c670
GitHub-Last-Rev: df63086c54071ecf3369142a0ed04197eb30091e
GitHub-Pull-Request: golang/net#230
Reviewed-on: https://go-review.googlesource.com/c/net/+/646555
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Damien Neil <dneil@google.com>