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Alt-svc: support IPv6 alt-authority #11737

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oliverpool opened this issue Aug 25, 2023 · 1 comment
Closed

Alt-svc: support IPv6 alt-authority #11737

oliverpool opened this issue Aug 25, 2023 · 1 comment
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@bagder
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@oliverpool
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oliverpool commented Aug 25, 2023 •
edited

I did this

Run curl -v --alt-svc cache "https://caddy.pfad.fr"

caddy.pfad.fr is a test server which replies with an Alt-svc header containing an IPv6 as alt-authority:

alt-svc: h3="[2a01:4f8:c0c:9a6d::42]:443"; ma=2592000

I expected the following

The cache file to be populated.

Instead, the cache file is empty and I see in the logs:

* Excessive alt-svc host name, ignoring.
< alt-svc: h3="[2a01:4f8:c0c:9a6d::42]:443"; ma=2592000

Triggered by this code:

curl/lib/altsvc.c

Lines 502 to 507 in c2212c0

const char *hostp = p;
while(*p && (ISALNUM(*p) || (*p == '.') || (*p == '-')))
p++;
len = p - hostp;
if(!len || (len >= MAX_ALTSVC_HOSTLEN)) {
infof(data, "Excessive alt-svc host name, ignoring.");

Relevant specifications:

  • alt-authority = quoted-string ; containing [ uri-host ] ":" port RFC7838
  • uri-host = <host, see [RFC3986], Section 3.2.2> RFC7230
  • host = IP-literal / IPv4address / reg-name RFC3986
  • IP-literal = "[" ( IPv6address / IPvFuture ) "]" RFC3986 as well

Hence I think that h3="[2a01:4f8:c0c:9a6d::42]:443"; ma=2592000 is a valid alt-svc header value and should be correctly handled by curl.

Background information:

Each of my service listens on 1 dedicated IPv6 address on the same machine. The traffic to the shared IPv4 gets forwarded to the right service thanks to snid (which uses SNI). However this setup can't handle UDP packets, hence I make http3 only available on IPv6.

Possible workaround: publish AAAA-only DNS record and use this domain as alt-svc (so IPv4 clients will waste a bit of their resources).

curl/libcurl version

curl 8.2.1 (x86_64-pc-linux-gnu) libcurl/8.2.1 OpenSSL/3.1.2 zlib/1.3 brotli/1.0.9 zstd/1.5.5 libidn2/2.3.4 libpsl/0.21.2 (+libidn2/2.3.4) libssh2/1.11.0 nghttp2/1.55.1
Release-Date: 2023-07-26
Protocols: dict file ftp ftps gopher gophers http https imap imaps mqtt pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp
Features: alt-svc AsynchDNS brotli GSS-API HSTS HTTP2 HTTPS-proxy IDN IPv6 Kerberos Largefile libz NTLM NTLM_WB PSL SPNEGO SSL threadsafe TLS-SRP UnixSockets zstd

operating system

Arch Linux:
Linux 6.4.11-arch2-1 #1 SMP PREEMPT_DYNAMIC Sat, 19 Aug 2023 15:38:34 +0000 x86_64 GNU/Linux
@oliverpool oliverpool mentioned this issue Aug 27, 2023
Closed
@bagder bagder self-assigned this Aug 27, 2023
@bagder bagder added the HTTP label Aug 27, 2023
bagder added a commit that referenced this issue Aug 27, 2023
@bagder
altvc: accept and parse IPv6 address in response headers
c2aed1f 
Store numerical IPv6 addresses in the alt-svc file with the brackets
present.

Verify with test 437 and 438

Fixes #11737
Reported-by: oliverpool on github
Closes #.....
@bagder bagder mentioned this issue Aug 27, 2023
Closed
bagder added a commit that referenced this issue Aug 28, 2023
@bagder
altvc: accept and parse IPv6 address in response headers
aa97315 
Store numerical IPv6 addresses in the alt-svc file with the brackets
present.

Verify with test 437 and 438

Fixes #11737
Reported-by: oliverpool on github
Closes #11743
bagder added a commit that referenced this issue Aug 28, 2023
@bagder
altsvc: accept and parse IPv6 address in response headers
3d9c429 
Store numerical IPv6 addresses in the alt-svc file with the brackets
present.

Verify with test 437 and 438

Fixes #11737
Reported-by: oliverpool on github
Closes #11743
@bagder bagder closed this as completed in 25ca79d Aug 28, 2023
@oliverpool
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@bagder thank you for the quick fix! (and your amazing work in general!)

ptitSeb pushed a commit to wasix-org/curl that referenced this issue Sep 25, 2023
@bagder @ptitSeb
altsvc: accept and parse IPv6 addresses in response headers
cf886ee 
Store numerical IPv6 addresses in the alt-svc file with the brackets
present.

Verify with test 437 and 438

Fixes curl#11737
Reported-by: oliverpool on github
Closes curl#11743
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altvc: accept and parse IPv6 address in response headers curl/curl
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