From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DDB9C18C03F for ; Tue, 16 Sep 2025 00:06:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757981172; cv=none; b=qngXe0zguUsQ0pHlCXYRahimgupFUNnZEWub/zZIxbLYyLnnAtC6Z/yDpyas6009h/vPLel20pyfCQdKOrqM/DXHZO0T3b7r5dlvuPW8TBKDgEpc1OfvjpHluBTZa0SW4iGnavYqISxjNl5vHBBbUg+EF14a6xREpYZIny34Dso= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757981172; c=relaxed/simple; bh=qUFpyAZ3uGPBh+Tq0SPLxenJNNVZd2cn+UyXvNhUUPo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RAy+4qOwHKNABF1agr18RP8IPVtaPpmuWhCfiQoMBA1zi5I2n9DxDt/SIirnVDl/EyEqAHD6qpgDlCc6E5Ghoqpo8Y1mgOifQJe3w61GZXCF2KQnMwjQZw45RfLOjuiYfAQO7kVzgbDphUYy2lR+V2AuLja/jtl8/FZodiJp2ws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nIpHnNaJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nIpHnNaJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F207C4CEF1; Tue, 16 Sep 2025 00:06:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757981172; bh=qUFpyAZ3uGPBh+Tq0SPLxenJNNVZd2cn+UyXvNhUUPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nIpHnNaJoueIhb830YMH/pIAKURHoXOtYsIU/KdNO3vjJSq6kQ1cU/qrQvckYuNIe IDRU3yZL+CS0dHR/xmNBBIeR+gh7bnnTW5PsiekV2sWKmI/Ant2XMR2ZnwkeL3zeKF MM9izr8vmHOhjgapyjcXYDn3w5kFCHRcEYHx5E09vInTD7NaQGcZJf22c1VHUVKOng xFa9Pf9JPZwGBzesWxsPSfpns+4jcO/OZrQ7CZr4xveZRMiHFYjBzQPpSsVse+sPNe U+nxtDU5STRaaPF9d7YKVBNgKB492KiH8IcGgGVYZHUee4Rh5LNLagd1I4aiBUIesw o0lUxarN3+jEA== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, willemb@google.com, Jakub Kicinski , Daniel Zahka Subject: [PATCH net-next v12 09/19] net: psp: update the TCP MSS to reflect PSP packet overhead Date: Mon, 15 Sep 2025 17:05:49 -0700 Message-ID: <20250916000559.1320151-10-kuba@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250916000559.1320151-1-kuba@kernel.org> References: <20250916000559.1320151-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit PSP eats 40B of header space. Adjust MSS appropriately. We can either modify tcp_mtu_to_mss() / tcp_mss_to_mtu() or reuse icsk_ext_hdr_len. The former option is more TCP specific and has runtime overhead. The latter is a bit of a hack as PSP is not an ext_hdr. If one squints hard enough, UDP encap is just a more practical version of IPv6 exthdr, so go with the latter. Happy to change. Reviewed-by: Willem de Bruijn Signed-off-by: Daniel Zahka Signed-off-by: Jakub Kicinski --- Notes: v6: - make psp_sk_overhead() add 40B of encapsulation overhead. v1: - https://lore.kernel.org/netdev/20240510030435.120935-8-kuba@kernel.org/ --- include/net/psp/types.h | 3 +++ include/net/psp/functions.h | 14 ++++++++++++++ net/ipv4/tcp_ipv4.c | 4 ++-- net/ipv6/ipv6_sockglue.c | 6 +++++- net/ipv6/tcp_ipv6.c | 6 +++--- net/psp/psp_sock.c | 5 +++++ 6 files changed, 32 insertions(+), 6 deletions(-) diff --git a/include/net/psp/types.h b/include/net/psp/types.h index b0e32e7165a3..f93ad0e6c04f 100644 --- a/include/net/psp/types.h +++ b/include/net/psp/types.h @@ -93,6 +93,9 @@ struct psp_dev_caps { #define PSP_MAX_KEY 32 +#define PSP_HDR_SIZE 16 /* We don't support optional fields, yet */ +#define PSP_TRL_SIZE 16 /* AES-GCM/GMAC trailer size */ + struct psp_skb_ext { __be32 spi; u16 dev_id; diff --git a/include/net/psp/functions.h b/include/net/psp/functions.h index 0d7141230f47..183a3c9216b7 100644 --- a/include/net/psp/functions.h +++ b/include/net/psp/functions.h @@ -5,6 +5,7 @@ #include #include +#include #include #include #include @@ -143,6 +144,14 @@ static inline struct psp_assoc *psp_skb_get_assoc_rcu(struct sk_buff *skb) return psp_sk_get_assoc_rcu(skb->sk); } + +static inline unsigned int psp_sk_overhead(const struct sock *sk) +{ + int psp_encap = sizeof(struct udphdr) + PSP_HDR_SIZE + PSP_TRL_SIZE; + bool has_psp = rcu_access_pointer(sk->psp_assoc); + + return has_psp ? psp_encap : 0; +} #else static inline void psp_sk_assoc_free(struct sock *sk) { } static inline void @@ -182,6 +191,11 @@ static inline struct psp_assoc *psp_skb_get_assoc_rcu(struct sk_buff *skb) { return NULL; } + +static inline unsigned int psp_sk_overhead(const struct sock *sk) +{ + return 0; +} #endif static inline unsigned long diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a448eb62efb1..aee406adb67c 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -293,9 +293,9 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) inet->inet_dport = usin->sin_port; sk_daddr_set(sk, daddr); - inet_csk(sk)->icsk_ext_hdr_len = 0; + inet_csk(sk)->icsk_ext_hdr_len = psp_sk_overhead(sk); if (inet_opt) - inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; + inet_csk(sk)->icsk_ext_hdr_len += inet_opt->opt.optlen; tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index e66ec623972e..a61e742794f9 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -49,6 +49,7 @@ #include #include #include +#include #include @@ -107,7 +108,10 @@ struct ipv6_txoptions *ipv6_update_options(struct sock *sk, !((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) && inet_sk(sk)->inet_daddr != LOOPBACK4_IPV6) { struct inet_connection_sock *icsk = inet_csk(sk); - icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen; + + icsk->icsk_ext_hdr_len = + psp_sk_overhead(sk) + + opt->opt_flen + opt->opt_nflen; icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie); } } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 83490cab2e4a..e154163c6c24 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -302,10 +302,10 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, sk->sk_gso_type = SKB_GSO_TCPV6; ip6_dst_store(sk, dst, NULL, NULL); - icsk->icsk_ext_hdr_len = 0; + icsk->icsk_ext_hdr_len = psp_sk_overhead(sk); if (opt) - icsk->icsk_ext_hdr_len = opt->opt_flen + - opt->opt_nflen; + icsk->icsk_ext_hdr_len += opt->opt_flen + + opt->opt_nflen; tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr); diff --git a/net/psp/psp_sock.c b/net/psp/psp_sock.c index 8ebccee94593..10e1fda30aa0 100644 --- a/net/psp/psp_sock.c +++ b/net/psp/psp_sock.c @@ -180,6 +180,7 @@ int psp_sock_assoc_set_tx(struct sock *sk, struct psp_dev *psd, u32 version, struct psp_key_parsed *key, struct netlink_ext_ack *extack) { + struct inet_connection_sock *icsk; struct psp_assoc *pas, *dummy; int err; @@ -236,6 +237,10 @@ int psp_sock_assoc_set_tx(struct sock *sk, struct psp_dev *psd, tcp_write_collapse_fence(sk); pas->upgrade_seq = tcp_sk(sk)->rcv_nxt; + icsk = inet_csk(sk); + icsk->icsk_ext_hdr_len += psp_sk_overhead(sk); + icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie); + exit_free_dummy: kfree(dummy); exit_unlock: -- 2.51.0