From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from chinatelecom.cn (prt-mail.chinatelecom.cn [42.123.76.227]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B089B70 for ; Mon, 12 Jul 2021 08:06:59 +0000 (UTC) HMM_SOURCE_IP:172.18.0.48:60210.146747981 HMM_ATTACHE_NUM:0000 HMM_SOURCE_TYPE:SMTP Received: from clientip-36.111.140.26?logid-edd049964cd44c46877e2b3333bafce2 (unknown [172.18.0.48]) by chinatelecom.cn (HERMES) with SMTP id 917212800CB; Mon, 12 Jul 2021 16:06:58 +0800 (CST) X-189-SAVE-TO-SEND: liyonglong@chinatelecom.cn Received: from ([172.18.0.48]) by app0024 with ESMTP id edd049964cd44c46877e2b3333bafce2 for mptcp@lists.linux.dev; Mon Jul 12 16:06:59 2021 X-Transaction-ID: edd049964cd44c46877e2b3333bafce2 X-filter-score: X-Real-From: liyonglong@chinatelecom.cn X-Receive-IP: 172.18.0.48 X-MEDUSA-Status: 0 Sender: liyonglong@chinatelecom.cn Subject: Re: [MPTCP][PATCH mptcp-next] Squash to "mptcp: build ADD_ADDR/echo-ADD_ADDR option according pm.add_signal" To: Geliang Tang Cc: mptcp@lists.linux.dev References: <9365b79b245b8a87af18ca458c67820d47de2515.1626016228.git.geliangtang@gmail.com> <80fa33a249c2ecc7edd9d0047dd84f163307cee7.1626016292.git.geliangtang@gmail.com> <347f6214-cc6b-2af2-c1e7-d9ac7f77f87e@chinatelecom.cn> From: Yonglong Li Message-ID: <4f790fa7-f99e-401e-d266-8fd85921204a@chinatelecom.cn> Date: Mon, 12 Jul 2021 16:06:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 2021/7/12 15:33, Geliang Tang wrote: > Hi Yonglong, > > Yonglong Li 于2021年7月12日周一 上午9:34写道： >> >> >> >> On 2021/7/11 23:15, Geliang Tang wrote: >>> I think there're still some issues in v8: >>> >>> The remaining value is incorrect since "remaining += opt_size;" in the >>> "drop other suboptions" checks has been called twice in >>> mptcp_pm_add_addr_signal and mptcp_established_options_add_addr. >>> >> I think "remaining" in mptcp_pm_add_addr_signal does not touch "remaining" in >> mptcp_established_options_add_addr. >> >>> opts->local and opts->remote in mptcp_pm_add_addr_signal need be >>> populate after the length chech, not before the check.] >>> >>> The squash-to patch keeped the more orignal code unchanged, and just do >>> the least, necessary modifications. >>> >> Agree opts->local and opts->remote should be asigned after the length check. >> But if keep the length check out of mptcp_pm_add_addr_signal (out of pm lock ) >> as orignal code, there is a race that: >> >> ==> a add addr event (pm.addr_signal == MPTCP_ADD_ADDR_SIGNAL) >> ==> call mptcp_pm_add_addr_signal >> ==> a echo add addr event trigger (pm.addr_signal == MPTCP_ADD_ADDR_ECHO|MPTCP_ADD_ADDR_SIGNAL) >> ==> at this time opts->remote is empty and the length is incorrect. >> > > What will happen in v8 when this race occurs? How dose v8 deal with the > race? Hi Geliang, thinks for your patience. I think v8 doesn't have this issue: ==> a add addr event (pm.addr_signal == MPTCP_ADD_ADDR_SIGNAL) ==> call mptcp_pm_add_addr_signal, save pm.addr_signal to add_addr and save addr in opts under pm.lock ==> a echo add addr event trigger (pm.addr_signal == MPTCP_ADD_ADDR_ECHO), but add_addr doesn't changed. ==> use add_addr and opts to check length. ==> next send ack process will deal with MPTCP_ADD_ADDR_ECHO event. > >> So I think the orignal code is incorrect. WDYT? >> >>> Drop the "drop other suboptions" check in mptcp_pm_add_addr_signal. >>> >>> Change arguments of mptcp_pm_add_addr_signal. >>> >>> Keep mptcp_add_addr_len unchanged. >>> >>> Signed-off-by: Geliang Tang >>> --- >>> net/mptcp/options.c | 35 +++++++++++++++++------------------ >>> net/mptcp/pm.c | 23 +++++++++-------------- >>> net/mptcp/protocol.h | 27 +++++++++------------------ >>> 3 files changed, 35 insertions(+), 50 deletions(-) >>> >>> diff --git a/net/mptcp/options.c b/net/mptcp/options.c >>> index 5c0ad9b90866..93ad7b134f74 100644 >>> --- a/net/mptcp/options.c >>> +++ b/net/mptcp/options.c >>> @@ -663,16 +663,14 @@ 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)) >>> - 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))) && >>> + if ((mptcp_pm_should_add_signal_echo(msk) || >>> + (mptcp_pm_should_add_signal_addr(msk) && >>> + (msk->pm.local.family == AF_INET6 || msk->pm.local.port))) && >>> skb && skb_is_tcp_pure_ack(skb)) { >>> pr_debug("drop other suboptions"); >>> opts->suboptions = 0; >>> @@ -682,7 +680,12 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff * >>> drop_other_suboptions = true; >>> } >>> >>> - len = mptcp_add_addr_len(opts, add_addr); >>> + if (!mptcp_pm_should_add_signal(msk) || >>> + !mptcp_pm_add_addr_signal(msk, remaining, &opts->local, &opts->remote, &echo, &port)) >>> + return false; >>> + >>> + family = echo ? opts->remote.family : opts->local.family; >>> + len = mptcp_add_addr_len(family, echo, port); >>> if (remaining < len) >>> return false; >>> >>> @@ -690,15 +693,14 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff * >>> if (drop_other_suboptions) >>> *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 +1255,10 @@ 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 264f522af530..399b59cb7563 100644 >>> --- a/net/mptcp/pm.c >>> +++ b/net/mptcp/pm.c >>> @@ -253,12 +253,13 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup) >>> >>> /* path manager helpers */ >>> >>> -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) >>> +bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining, >>> + struct mptcp_addr_info *saddr, struct mptcp_addr_info *daddr, >>> + bool *echo, bool *port) >>> { >>> int ret = false; >>> u8 add_addr; >>> + u8 family; >>> >>> spin_lock_bh(&msk->pm.lock); >>> >>> @@ -266,21 +267,15 @@ 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; >>> + *echo = mptcp_pm_should_add_signal_echo(msk); >>> + *port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port); >>> >>> - 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))) && >>> - skb && skb_is_tcp_pure_ack(skb)) { >>> - remaining += opt_size; >>> - } >>> - >>> - if (remaining < mptcp_add_addr_len(opts, *add_addr)) >>> + 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; >>> + *daddr = msk->pm.remote; >>> add_addr = READ_ONCE(msk->pm.addr_signal); >>> if (mptcp_pm_should_add_signal_echo(msk)) >>> add_addr &= ~BIT(MPTCP_ADD_ADDR_ECHO); >>> diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h >>> index 937e0309e340..4b63cc6079fa 100644 >>> --- a/net/mptcp/protocol.h >>> +++ b/net/mptcp/protocol.h >>> @@ -766,25 +766,16 @@ 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(int 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; >>> @@ -798,9 +789,9 @@ 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, struct sk_buff *skb, >>> - unsigned int opt_size, unsigned int remaining, >>> - struct mptcp_out_options *opts, u8 *add_addr); >>> +bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining, >>> + struct mptcp_addr_info *saddr, struct mptcp_addr_info *daddr, >>> + bool *echo, bool *port); >>> 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 > -- Li YongLong