[PATCH net-next 1/6] mptcp: move drop_other_suboptions check under pm lock
From: Mat Martineau <hidden>
Date: 2021-08-24 01:06:03
Also in:
mptcp
Subsystem:
networking [general], networking [mptcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthieu Baerts, Mat Martineau, Linus Torvalds
From: Yonglong Li <redacted> This patch moved the drop_other_suboptions check from mptcp_established_options_add_addr() into mptcp_pm_add_addr_signal(), do it under the PM lock to avoid the race between this check and mptcp_pm_add_addr_signal(). For this, added a new parameter for mptcp_pm_add_addr_signal() to get the drop_other_suboptions value. And drop the other suboptions after the option length check if drop_other_suboptions is true. Additionally, always drop the other suboption for TCP pure ack: that makes both the code simpler and the MPTCP behaviour more consistent. Co-developed-by: Geliang Tang <redacted> Signed-off-by: Geliang Tang <redacted> Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Yonglong Li <redacted> Signed-off-by: Mat Martineau <redacted> --- net/mptcp/options.c | 28 ++++++++++++++-------------- net/mptcp/pm.c | 15 +++++++++++++-- net/mptcp/protocol.h | 6 ++++-- 3 files changed, 31 insertions(+), 18 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index bebb759f470e..4c37f4b215ee 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c@@ -667,29 +667,29 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff * bool port; int len; - if ((mptcp_pm_should_add_signal_ipv6(msk) || - mptcp_pm_should_add_signal_port(msk) || - mptcp_pm_should_add_signal_echo(msk)) && - skb && skb_is_tcp_pure_ack(skb)) { - pr_debug("drop other suboptions"); - opts->suboptions = 0; - opts->ext_copy.use_ack = 0; - opts->ext_copy.use_map = 0; - remaining += opt_size; - drop_other_suboptions = true; - } - + /* add addr will strip the existing options, be sure to avoid breaking + * MPC/MPJ handshakes + */ if (!mptcp_pm_should_add_signal(msk) || - !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port))) + (opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) || + !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, &opts->addr, + &echo, &port, &drop_other_suboptions)) return false; + if (drop_other_suboptions) + remaining += opt_size; len = mptcp_add_addr_len(opts->addr.family, echo, port); if (remaining < len) return false; *size = len; - if (drop_other_suboptions) + if (drop_other_suboptions) { + pr_debug("drop other suboptions"); + opts->suboptions = 0; + opts->ext_copy.use_ack = 0; + opts->ext_copy.use_map = 0; *size -= opt_size; + } opts->suboptions |= OPTION_MPTCP_ADD_ADDR; if (!echo) { opts->ahmac = add_addr_generate_hmac(msk->local_key,
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 0ed3e565f8f8..24e2f6f6178b 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c@@ -251,8 +251,10 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup) /* path manager helpers */ -bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining, - struct mptcp_addr_info *saddr, bool *echo, bool *port) +bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct sk_buff *skb, + unsigned int opt_size, unsigned int remaining, + struct mptcp_addr_info *saddr, bool *echo, + bool *port, bool *drop_other_suboptions) { int ret = false;
@@ -262,6 +264,15 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining, if (!mptcp_pm_should_add_signal(msk)) goto out_unlock; + /* always drop every other options for pure ack ADD_ADDR; this is a + * plain dup-ack from TCP perspective. The other MPTCP-relevant info, + * if any, will be carried by the 'original' TCP ack + */ + if (skb && skb_is_tcp_pure_ack(skb)) { + remaining += opt_size; + *drop_other_suboptions = true; + } + *echo = mptcp_pm_should_add_signal_echo(msk); *port = mptcp_pm_should_add_signal_port(msk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index bc1bfd7ac9c1..40bc9d31e1fa 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h@@ -794,8 +794,10 @@ static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list) return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1; } -bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining, - struct mptcp_addr_info *saddr, bool *echo, bool *port); +bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct sk_buff *skb, + unsigned int opt_size, unsigned int remaining, + struct mptcp_addr_info *saddr, bool *echo, + bool *port, bool *drop_other_suboptions); bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, struct mptcp_rm_list *rm_list); int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
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2.33.0