Re: [MPTCP][PATCH v2 mptcp-next] Squash to "mptcp: build ADD_ADDR/echo-ADD_ADDR option according pm.add_signal"

[Yonglong Li <liyonglong@chinatelecom.cn>]

On 2021/7/13 14:44, Geliang Tang wrote:
> In v8, opts->local and opts->remote in mptcp_pm_add_addr_signal need be
> populated after the length check, not before the check.
> 
> This patch fixed it. And keep the more original code unchanged, just do
> the least, necessary modifications.
> 
> - Keep mptcp_add_addr_len unchanged.
> - populate opts->local or opts->remote after the length check, don't
>   populate both of them.
> - add back 'echo' and 'port' arguments of mptcp_pm_add_addr_signal().
> - add a new arguments drop_other_suboptions for
>   mptcp_pm_add_addr_signal(), and do the drop_other_suboptions check in it.
> - drop other suboptions in mptcp_established_options_add_addr() after the
>   length check.
> - update mptcp_pm_should_add_signal_ipv6() and
>   mptcp_pm_should_add_signal_port(), not drop them. They will be used in
>   the drop_other_suboptions check and in mptcp_pm_nl_addr_send_ack() in the
>   next squash-to patch.
> 
> v2:
>  - move the drop_other_suboptions check into mptcp_pm_add_addr_signal().
>  - drop other suboptions in mptcp_established_options_add_addr() after the
>    length check.
>  - add back mptcp_pm_should_add_signal_ipv6() and
>    mptcp_pm_should_add_signal_port().
>  - populate opts->local or opts->remote, not both of them.
> 
> Signed-off-by: Geliang Tang <geliangtang@gmail.com>
> ---
>  net/mptcp/options.c  | 43 +++++++++++++++++++------------------------
>  net/mptcp/pm.c       | 29 +++++++++++++++++------------
>  net/mptcp/protocol.h | 30 ++++++++++++------------------
>  3 files changed, 48 insertions(+), 54 deletions(-)
> 
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index 5c0ad9b90866..37ff15aeb2f7 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -663,42 +663,40 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *
>  	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
>  	bool drop_other_suboptions = false;
>  	unsigned int opt_size = *size;
> -	u8 add_addr;
> +	bool echo;
> +	bool port;
> +	u8 family;
>  	int len;
>  
>  	if (!mptcp_pm_should_add_signal(msk) ||
> -	    !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, opts, &add_addr))
> +	    !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, opts,
> +		    &echo, &port, &drop_other_suboptions))
>  		return false;
>  
> -	if (((add_addr & BIT(MPTCP_ADD_ADDR_ECHO)) ||
> -	     ((add_addr & BIT(MPTCP_ADD_ADDR_SIGNAL)) &&
> -	      (opts->local.family == AF_INET6 || opts->local.port))) &&
> -	    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;
> +	if (drop_other_suboptions)
>  		remaining += opt_size;
> -		drop_other_suboptions = true;
> -	}
> -
> -	len = mptcp_add_addr_len(opts, add_addr);
> +	family = echo ? opts->remote.family : opts->local.family;
> +	len = mptcp_add_addr_len(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 (!(add_addr & BIT(MPTCP_ADD_ADDR_ECHO)) &&
> -	    (add_addr & BIT(MPTCP_ADD_ADDR_SIGNAL))) {
> +	if (!echo) {
>  		opts->ahmac = add_addr_generate_hmac(msk->local_key,
>  						     msk->remote_key,
>  						     &opts->local);
>  	}
> -	pr_debug("addr_signal:%x, echo=%d, local_addr_id=%d, ahmac=%llu, local_port=%d, remote_addr_id=%d, remote_port=%d",
> -		 add_addr, (opts->ahmac == 0), opts->local.id, opts->ahmac,
> -		 ntohs(opts->local.port), opts->remote.id, ntohs(opts->remote.port));
> +	pr_debug("local_id=%d, local_port=%d, remote_id=%d, remote_port=%d, ahmac=%llu, echo=%d",
> +		 opts->local.id, ntohs(opts->local.port), opts->remote.id,
> +		 ntohs(opts->remote.port), opts->ahmac, echo);
>  
>  	return true;
>  }
> @@ -1253,13 +1251,10 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
>  
>  mp_capable_done:
>  	if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
> -		struct mptcp_addr_info *addr = &opts->remote;
> +		struct mptcp_addr_info *addr = opts->ahmac ? &opts->local : &opts->remote;
>  		u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
>  		u8 echo = MPTCP_ADDR_ECHO;
>  
> -		if (opts->ahmac)
> -			addr = &opts->local;
> -
>  #if IS_ENABLED(CONFIG_MPTCP_IPV6)
>  		if (addr->family == AF_INET6)
>  			len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 88b5db9114f4..62734d6b534d 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -255,10 +255,12 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup)
>  
>  bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct sk_buff *skb,
>  			      unsigned int opt_size, unsigned int remaining,
> -			      struct mptcp_out_options *opts,  u8 *add_addr)
> +			      struct mptcp_out_options *opts, bool *echo,
> +			      bool *port, bool *drop_other_suboptions)
>  {
>  	int ret = false;
>  	u8 add_addr;
> +	u8 family;
>  
>  	spin_lock_bh(&msk->pm.lock);
>  
> @@ -266,25 +268,28 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct sk_buff *skb,
>  	if (!mptcp_pm_should_add_signal(msk))
>  		goto out_unlock;
>  
> -	opts->local = msk->pm.local;
> -	opts->remote = msk->pm.remote;
> -	*add_addr = msk->pm.addr_signal;
> -
> -	if (((msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_ECHO)) ||
> -	     ((msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL)) &&
> -	      (msk->pm.local.family == AF_INET6 || msk->pm.local.port))) &&
> +	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)) {
>  		remaining += opt_size;
> +		*drop_other_suboptions = true;
>  	}
>  
> -	if (remaining < mptcp_add_addr_len(opts, *add_addr))
> +	*echo = mptcp_pm_should_add_signal_echo(msk);
> +	*port = mptcp_pm_should_add_signal_port(msk);
> +
> +	family = *echo ? msk->pm.remote.family : msk->pm.local.family;
> +	if (remaining < mptcp_add_addr_len(family, *echo, *port))
>  		goto out_unlock;
>  
> -	*saddr = msk->pm.local;
> -	if (*echo)
> +	if (*echo) {
> +		opts->remote = msk->pm.remote;
>  		add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO);
> -	else
> +	} else {
> +		opts->local = msk->pm.local;
>  		add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL);
> +	}
>  	WRITE_ONCE(msk->pm.addr_signal, add_addr);
>  	ret = true;
>  
> diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
> index 937e0309e340..08a76eaea2e5 100644
> --- a/net/mptcp/protocol.h
> +++ b/net/mptcp/protocol.h
> @@ -753,12 +753,14 @@ static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
>  
>  static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
>  {
> -	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
> +	return (mptcp_pm_should_add_signal_addr(msk) && msk->pm.local.family == AF_INET6) ||
> +		(mptcp_pm_should_add_signal_echo(msk) && msk->pm.remote.family == AF_INET6);
>  }Should we use READ_ONCE to read remote.family?

>  
>  static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
>  {
> -	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_PORT);
> +	return (mptcp_pm_should_add_signal_addr(msk) && msk->pm.local.port) ||
> +		(mptcp_pm_should_add_signal_echo(msk) && msk->pm.remote.port);
>  }
Should we use READ_ONCE to read remote.port?

>  
>  static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
> @@ -766,25 +768,16 @@ static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
>  	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
>  }
>  
> -static inline unsigned int mptcp_add_addr_len(struct mptcp_out_options *opts,
> -					      u8 add_addr)
> +static inline unsigned int mptcp_add_addr_len(u8 family, bool echo, bool port)
>  {
> -	struct mptcp_addr_info *addr = &opts->remote;
> -	u8 len = 0;
> +	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
>  
> -	if (!(add_addr & BIT(MPTCP_ADD_ADDR_ECHO)) &&
> -	    (add_addr & BIT(MPTCP_ADD_ADDR_SIGNAL))) {
> -		addr = &opts->local;
> +	if (family == AF_INET6)
> +		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
> +	if (!echo)
>  		len += MPTCPOPT_THMAC_LEN;
> -	}
> -
> -	if (addr->family == AF_INET6)
> -		len += TCPOLEN_MPTCP_ADD_ADDR6_BASE;
> -	else
> -		len += TCPOLEN_MPTCP_ADD_ADDR_BASE;
> -
>  	/* account for 2 trailing 'nop' options */
> -	if (addr->port)
> +	if (port)
>  		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
>  
>  	return len;
> @@ -800,7 +793,8 @@ static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
>  
>  bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct sk_buff *skb,
>  			      unsigned int opt_size, unsigned int remaining,
> -			      struct mptcp_out_options *opts,  u8 *add_addr);
> +			      struct mptcp_out_options *opts, bool *echo,
> +			      bool *port, bool *drop_other_suboptions);
Uhm... I think this function has too many parameters... but not serious.

>  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);
> 

-- 
Li YongLong