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[PATCH net-next] mptcp: change mptcp_established_options() to return opt_size

Matthieu Baerts posted 1 patch 6 days, 19 hours ago
Failed in applying to current master (apply log)
include/net/mptcp.h   | 18 +++++++++---------
net/ipv4/tcp_output.c |  7 ++++---
net/mptcp/options.c   | 31 ++++++++++++++++---------------
3 files changed, 29 insertions(+), 27 deletions(-)
[PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
Posted by Matthieu Baerts 6 days, 19 hours ago 
From: Eric Dumazet <edumazet@google.com>

Instead of passing opt_size address to mptcp_established_options(),
change this function to return it by value.

This removes the need for an expensive stack canary in
tcp_established_options() when CONFIG_STACKPROTECTOR_STRONG=y.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-92 (-92)
Function                                     old     new   delta
tcp_options_write.isra                      1423    1407     -16
mptcp_established_options                   2746    2720     -26
tcp_established_options                      553     503     -50
Total: Before=22110750, After=22110658, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/mptcp.h   | 18 +++++++++---------
 net/ipv4/tcp_output.c |  7 ++++---
 net/mptcp/options.c   | 31 ++++++++++++++++---------------
 3 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index f7263fe2a2e40b507257c3720cc2d78d37357d6d..cd4639beceaa53c573135ddaeb7528a80b4ca824 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -149,9 +149,9 @@ bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
 		       unsigned int *size, struct mptcp_out_options *opts);
 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
 			  struct mptcp_out_options *opts);
-bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
-			       unsigned int *size, unsigned int remaining,
-			       struct mptcp_out_options *opts);
+int mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+			      unsigned int remaining,
+			      struct mptcp_out_options *opts);
 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
  void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
@@ -266,13 +266,13 @@ static inline bool mptcp_synack_options(const struct request_sock *req,
 	return false;
 }
 -static inline bool mptcp_established_options(struct sock *sk,
-					     struct sk_buff *skb,
-					     unsigned int *size,
-					     unsigned int remaining,
-					     struct mptcp_out_options *opts)
+static inline int mptcp_established_options(struct sock *sk,
+					    struct sk_buff *skb,
+					    unsigned int *size,
+					    unsigned int remaining,
+					    struct mptcp_out_options *opts)
 {
-	return false;
+	return -1;
 }
  static inline bool mptcp_incoming_options(struct sock *sk,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ef0c10cd31c71ff585a937fde37f2b08b1214b5a..31b459ecbe8307a8660623038fea6fa7b0860f7f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1181,10 +1181,11 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 	 */
 	if (sk_is_mptcp(sk)) {
 		unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
-		unsigned int opt_size = 0;
+		int opt_size;
 -		if (mptcp_established_options(sk, skb, &opt_size, remaining,
-					      &opts->mptcp)) {
+		opt_size = mptcp_established_options(sk, skb, remaining,
+						     &opts->mptcp);
+		if (opt_size >= 0) {
 			opts->options |= OPTION_MPTCP;
 			size += opt_size;
 		}
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 8a1c5698983cff3082d68290626dd8f1e044527f..53528301394d70072dde6614feca6128ea949436 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -836,13 +836,14 @@ static bool mptcp_established_options_mp_fail(struct sock *sk,
 	return true;
 }
 -bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
-			       unsigned int *size, unsigned int remaining,
-			       struct mptcp_out_options *opts)
+int mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+			      unsigned int remaining,
+			      struct mptcp_out_options *opts)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
 	unsigned int opt_size = 0;
+	int total_size = 0;
 	bool snd_data_fin;
 	bool ret = false;
 @@ -852,20 +853,20 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 	 * option space.
 	 */
 	if (unlikely(__mptcp_check_fallback(msk) && !mptcp_check_infinite_map(skb)))
-		return true;
+		return 0;
  	if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
 		if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
 		    mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
-			*size += opt_size;
+			total_size += opt_size;
 			remaining -= opt_size;
 		}
 		/* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
 		if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
-			*size += opt_size;
+			total_size += opt_size;
 			remaining -= opt_size;
 		}
-		return true;
+		return total_size;
 	}
  	snd_data_fin = mptcp_data_fin_enabled(msk);
@@ -877,9 +878,9 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 		ret = true;
 		if (mptcp_established_options_mp_fail(sk, &mp_fail_size,
 						      remaining - opt_size, opts)) {
-			*size += opt_size + mp_fail_size;
+			total_size += opt_size + mp_fail_size;
 			remaining -= opt_size - mp_fail_size;
-			return true;
+			return total_size;
 		}
 	}
 @@ -887,27 +888,27 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 	 * TCP option space would be fatal
 	 */
 	if (WARN_ON_ONCE(opt_size > remaining))
-		return false;
+		return -1;
 -	*size += opt_size;
+	total_size += opt_size;
 	remaining -= opt_size;
 	if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) {
-		*size += opt_size;
+		total_size += opt_size;
 		remaining -= opt_size;
 		ret = true;
 	} else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
-		*size += opt_size;
+		total_size += opt_size;
 		remaining -= opt_size;
 		ret = true;
 	}
  	if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) {
-		*size += opt_size;
+		total_size += opt_size;
 		remaining -= opt_size;
 		ret = true;
 	}
 -	return ret;
+	return ret ? total_size : -1;
 }
  bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
-- 
2.54.0.1013.g208068f2d8-goog
Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
Posted by MPTCP CI 6 days, 18 hours ago 
Hi Eric,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal (except selftest_mptcp_join): Unstable: 1 failed test(s): packetdrill_add_addr ⚠️ 
- KVM Validation: normal (only selftest_mptcp_join): Success! ✅
- KVM Validation: debug (except selftest_mptcp_join): Success! ✅
- KVM Validation: debug (only selftest_mptcp_join): 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/26748250136

Initiator: Matthieu Baerts (NGI0)
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/4514016d2e89
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1103913


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 net-next] mptcp: change mptcp_established_options() to return opt_size
Posted by Matthieu Baerts 6 days, 18 hours ago 
Hello,

01 Jun 2026 21:13:02 MPTCP CI <wpasupplicant.patchew@gmail.com>:

> - KVM Validation: normal (except selftest_mptcp_join): Unstable: 1 failed test(s): packetdrill_add_addr ⚠️

FYI, this failed test is expected: the patch has been applied on an
older base to avoid conflicts, and these tests depend on new features.

Cheers,
Matt
Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
Posted by MPTCP CI 6 days, 19 hours ago 
Hi Eric,

Thank you for your modifications, that's great!

But sadly, our CI spotted some issues with it when trying to build it.

You can find more details there:

  https://github.com/multipath-tcp/mptcp_net-next/actions/runs/26748250142

Status: failure
Initiator: Matthieu Baerts (NGI0)
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/4514016d2e89
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1103913

Feel free to reply to this email if you cannot access logs, if you need
some support to fix the error, if this doesn't seem to be caused by your
modifications or if the error is a false positive one.

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

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