[PATCH mptcp-next v2] selftests: mptcp: use IPPROTO_MPTCP for getaddrinfo

[PATCH mptcp-next v2] selftests: mptcp: use IPPROTO_MPTCP for getaddrinfo

[Geliang Tang]

From: zhenwei pi <pizhenwei@bytedance.com>

mptcp_connect.c is a startup tutorial of MPTCP programming, however
there is a lack of ai_protocol(IPPROTO_MPTCP) usage. Add comment for
getaddrinfo MPTCP support.

This patch first uses IPPROTO_MPTCP to get addrinfo, and if glibc
version is too old, it falls back to using IPPROTO_TCP.

v2:
 - use IPPROTO_MPTCP for getaddrinfo

Co-developed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
I verified the correctness of getaddrinfo IPPROTO_MPTCP on Fedora 41
using the following steps:

 - Use 'yumdownloader' to download glibc src.rpm and install it.
 - Modify glibc.spec and add the patch "getaddrinfo.c: support
   MPTCP (BZ #29609)" in it.
 - Regenerate the glibc src.rpm package using 'rpm -bs'.
 - Use 'mock' to compile a new glibc src.rpm.
 - Use 'dnf update' to install the newly compiled glibc.rpm.
 - Compile and run mptcp_connect on the the system with new glibc.
---
 .../selftests/net/mptcp/mptcp_connect.c       | 21 +++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c
index c83a8b47bbdf..ac1349c4b9e5 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c
@@ -180,13 +180,26 @@ static void xgetnameinfo(const struct sockaddr *addr, socklen_t addrlen,
 }
 
 static void xgetaddrinfo(const char *node, const char *service,
-			 const struct addrinfo *hints,
+			 struct addrinfo *hints,
 			 struct addrinfo **res)
 {
+again:
 	int err = getaddrinfo(node, service, hints, res);
 
 	if (err) {
-		const char *errstr = getxinfo_strerr(err);
+		const char *errstr;
+
+		/* glibc starts to support MPTCP since v2.42.
+		 * For older versions, use IPPROTO_TCP to resolve,
+		 * and use TCP/MPTCP to create socket.
+		 * Link: https://sourceware.org/git/?p=glibc.git;a=commit;h=a8e9022e0f82
+		 */
+		if (err == EAI_SOCKTYPE) {
+			hints->ai_protocol = IPPROTO_TCP;
+			goto again;
+		}
+
+		errstr = getxinfo_strerr(err);
 
 		fprintf(stderr, "Fatal: getaddrinfo(%s:%s): %s\n",
 			node ? node : "", service ? service : "", errstr);
@@ -292,7 +305,7 @@ static int sock_listen_mptcp(const char * const listenaddr,
 {
 	int sock = -1;
 	struct addrinfo hints = {
-		.ai_protocol = IPPROTO_TCP,
+		.ai_protocol = IPPROTO_MPTCP,
 		.ai_socktype = SOCK_STREAM,
 		.ai_flags = AI_PASSIVE | AI_NUMERICHOST
 	};
@@ -356,7 +369,7 @@ static int sock_connect_mptcp(const char * const remoteaddr,
 			      int infd, struct wstate *winfo)
 {
 	struct addrinfo hints = {
-		.ai_protocol = IPPROTO_TCP,
+		.ai_protocol = IPPROTO_MPTCP,
 		.ai_socktype = SOCK_STREAM,
 	};
 	struct addrinfo *a, *addr;
-- 
2.43.0

Re: [PATCH mptcp-next v2] selftests: mptcp: use IPPROTO_MPTCP for getaddrinfo

[MPTCP CI]

Hi zhenwei,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal: Success! ✅
- KVM Validation: debug: Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/14350513463

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/1809498f6dbe
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=951400


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)

Re: [PATCH mptcp-next v2] selftests: mptcp: use IPPROTO_MPTCP for getaddrinfo

[Matthieu Baerts]

Hi Geliang, zhenwei pi,

On 09/04/2025 08:18, Geliang Tang wrote:
> From: zhenwei pi <pizhenwei@bytedance.com>
> 
> mptcp_connect.c is a startup tutorial of MPTCP programming, however
> there is a lack of ai_protocol(IPPROTO_MPTCP) usage. Add comment for
> getaddrinfo MPTCP support.
> 
> This patch first uses IPPROTO_MPTCP to get addrinfo, and if glibc
> version is too old, it falls back to using IPPROTO_TCP.
> 
> v2:
>  - use IPPROTO_MPTCP for getaddrinfo

Thank you for the v2, it looks good to me!

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Re: [PATCH mptcp-next v2] selftests: mptcp: use IPPROTO_MPTCP for getaddrinfo

[Matthieu Baerts]

On 10/04/2025 19:43, Matthieu Baerts wrote:
> Hi Geliang, zhenwei pi,
> 
> On 09/04/2025 08:18, Geliang Tang wrote:
>> From: zhenwei pi <pizhenwei@bytedance.com>
>>
>> mptcp_connect.c is a startup tutorial of MPTCP programming, however
>> there is a lack of ai_protocol(IPPROTO_MPTCP) usage. Add comment for
>> getaddrinfo MPTCP support.
>>
>> This patch first uses IPPROTO_MPTCP to get addrinfo, and if glibc
>> version is too old, it falls back to using IPPROTO_TCP.
>>
>> v2:
>>  - use IPPROTO_MPTCP for getaddrinfo
> 
> Thank you for the v2, it looks good to me!

Now in our tree (feat. for -next):

New patches for t/upstream:
- c0ae2744b5e2: selftests: mptcp: use IPPROTO_MPTCP for getaddrinfo
- Results: d16892726caa..24c84d5faab1 (export)

Tests are now in progress:

- export:
https://github.com/multipath-tcp/mptcp_net-next/commit/0a21820fc08404b0268c633d793e04f09fa0f72f/checks

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.