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| author | Jon Gjengset <jon@thesquareplanet.com> | 2025-10-04 20:10:07 -0400 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2025-10-04 17:10:07 -0700 |
| commit | 37fe4eff0e23ffbc251034b8001a1065c55f9951 (patch) | |
| tree | c8cc7dd8098e71f5955be591868c6d4f910a23e6 /src/platform | |
| parent | ef8e535c441f116f653e327cc66c21286a4104ec (diff) | |
| download | nng-37fe4eff0e23ffbc251034b8001a1065c55f9951.tar.gz nng-37fe4eff0e23ffbc251034b8001a1065c55f9951.tar.bz2 nng-37fe4eff0e23ffbc251034b8001a1065c55f9951.zip | |
remaps EAI_AGAIN to NNG_EADDRINVAL (#2169)
When running nng tests in CI under nix on Linux, I would see
`nng_dialer_start` fail with `NNG_EAGAIN` when invoked with `flags = 0`
and a URL of `tcp://999.888.777.666:8080` (this is in a test that is
supposed to check that dialing that gives you `NNG_EINVAL` or
`NNG_EADDRINVAL`).
This can happen if `nni_resolv_ip` in `posix_resolv_gai.c` gets
`EAI_AGAIN` from `getaddrinfo`, which the man pages suggest _can_ happen
due to "a temporary failure in name resolution". In the nix case, this
is due to the nix build sandbox, but it can also arise simply due to DNS
overload or misconfiguration.
In either case, nng should not bubble up `EAI_AGAIN` `as `NNG_EAGAIN`
from `nng_dialer_start`, as `NNG_EAGAIN` has a different semantic
meaning. `NNG_EAGAIN` is more equivalent to "would block", and should
only be generated through calls with the `NONBLOCK` flag. We don't have
a perfect mapping for `EAI_AGAIN`, but the closest is probably
`NNG_ADDRINVAL` to indicate that we failed to resolve the given address
(even if it's temporary). Another option would be to introduce another
error variant like `NNG_ENAMELOOKUP`, but that felt excessive to cover
this case.
Diffstat (limited to 'src/platform')
| -rw-r--r-- | src/platform/posix/posix_resolv_gai.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/platform/posix/posix_resolv_gai.c b/src/platform/posix/posix_resolv_gai.c index 2eba891b..fe6ee2d7 100644 --- a/src/platform/posix/posix_resolv_gai.c +++ b/src/platform/posix/posix_resolv_gai.c @@ -117,7 +117,13 @@ posix_gai_errno(int rv) #ifdef EAI_AGAIN case EAI_AGAIN: - return (NNG_EAGAIN); + // EAE_AGAIN means a temporary failure in name resolution. + // While that doesn't mean the address is invalid, it's the + // closest error code we currently have. This was previously + // mapped to NNG_EAGAIN, but that error code is used to + // indicate that non-blocking operations would block, so would + // be confusing to callers. + return (NNG_EADDRINVAL); #endif default: |