[MPTCP][PATCH net-next 04/16] mptcp: send out ADD_ADDR with echo flag

From: Geliang Tang
Date: Wed Sep 23 2020 - 20:41:23 EST


When the ADD_ADDR suboption has been received, we need to send out the same
ADD_ADDR suboption with echo-flag=1, and no HMAC.

Suggested-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
Reviewed-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>
---
net/mptcp/options.c | 27 ++++++++++++++++-----------
net/mptcp/pm.c | 18 +++++++++---------
net/mptcp/pm_netlink.c | 4 +++-
net/mptcp/protocol.h | 6 ++++--
4 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index a52a05effac9..a41996e6c6d7 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -242,7 +242,7 @@ static void mptcp_parse_option(const struct sk_buff *skb,
mp_opt->add_addr = 1;
mp_opt->port = 0;
mp_opt->addr_id = *ptr++;
- pr_debug("ADD_ADDR: id=%d", mp_opt->addr_id);
+ pr_debug("ADD_ADDR: id=%d, echo=%d", mp_opt->addr_id, mp_opt->echo);
if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) {
memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4);
ptr += 4;
@@ -579,10 +579,11 @@ static bool mptcp_established_options_add_addr(struct sock *sk,
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
struct mptcp_addr_info saddr;
+ bool echo;
int len;

if (!mptcp_pm_should_add_signal(msk) ||
- !(mptcp_pm_add_addr_signal(msk, remaining, &saddr)))
+ !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo)))
return false;

len = mptcp_add_addr_len(saddr.family);
@@ -594,22 +595,26 @@ static bool mptcp_established_options_add_addr(struct sock *sk,
if (saddr.family == AF_INET) {
opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
opts->addr = saddr.addr;
- opts->ahmac = add_addr_generate_hmac(msk->local_key,
- msk->remote_key,
- opts->addr_id,
- &opts->addr);
+ if (!echo) {
+ opts->ahmac = add_addr_generate_hmac(msk->local_key,
+ msk->remote_key,
+ opts->addr_id,
+ &opts->addr);
+ }
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
else if (saddr.family == AF_INET6) {
opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
opts->addr6 = saddr.addr6;
- opts->ahmac = add_addr6_generate_hmac(msk->local_key,
- msk->remote_key,
- opts->addr_id,
- &opts->addr6);
+ if (!echo) {
+ opts->ahmac = add_addr6_generate_hmac(msk->local_key,
+ msk->remote_key,
+ opts->addr_id,
+ &opts->addr6);
+ }
}
#endif
- pr_debug("addr_id=%d, ahmac=%llu", opts->addr_id, opts->ahmac);
+ pr_debug("addr_id=%d, ahmac=%llu, echo=%d", opts->addr_id, opts->ahmac, echo);

return true;
}
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 558462d87eb3..39a76620d0a5 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -13,11 +13,13 @@
/* path manager command handlers */

int mptcp_pm_announce_addr(struct mptcp_sock *msk,
- const struct mptcp_addr_info *addr)
+ const struct mptcp_addr_info *addr,
+ bool echo)
{
pr_debug("msk=%p, local_id=%d", msk, addr->id);

msk->pm.local = *addr;
+ WRITE_ONCE(msk->pm.add_addr_echo, echo);
WRITE_ONCE(msk->pm.add_addr_signal, true);
return 0;
}
@@ -135,15 +137,11 @@ void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
pr_debug("msk=%p remote_id=%d accept=%d", msk, addr->id,
READ_ONCE(pm->accept_addr));

- /* avoid acquiring the lock if there is no room for fouther addresses */
- if (!READ_ONCE(pm->accept_addr))
- return;
-
spin_lock_bh(&pm->lock);

- /* be sure there is something to signal re-checking under PM lock */
- if (READ_ONCE(pm->accept_addr) &&
- mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED))
+ if (!READ_ONCE(pm->accept_addr))
+ mptcp_pm_announce_addr(msk, addr, true);
+ else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED))
pm->remote = *addr;

spin_unlock_bh(&pm->lock);
@@ -164,7 +162,7 @@ void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id)
/* path manager helpers */

bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
- struct mptcp_addr_info *saddr)
+ struct mptcp_addr_info *saddr, bool *echo)
{
int ret = false;

@@ -178,6 +176,7 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
goto out_unlock;

*saddr = msk->pm.local;
+ *echo = READ_ONCE(msk->pm.add_addr_echo);
WRITE_ONCE(msk->pm.add_addr_signal, false);
ret = true;

@@ -226,6 +225,7 @@ void mptcp_pm_data_init(struct mptcp_sock *msk)
WRITE_ONCE(msk->pm.rm_addr_signal, false);
WRITE_ONCE(msk->pm.accept_addr, false);
WRITE_ONCE(msk->pm.accept_subflow, false);
+ WRITE_ONCE(msk->pm.add_addr_echo, false);
msk->pm.status = 0;

spin_lock_init(&msk->pm.lock);
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 4124bc581308..f6f96bc2046b 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -198,7 +198,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)

if (local) {
msk->pm.add_addr_signaled++;
- mptcp_pm_announce_addr(msk, &local->addr);
+ mptcp_pm_announce_addr(msk, &local->addr, false);
} else {
/* pick failed, avoid fourther attempts later */
msk->pm.local_addr_used = msk->pm.add_addr_signal_max;
@@ -266,6 +266,8 @@ void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
spin_unlock_bh(&msk->pm.lock);
__mptcp_subflow_connect((struct sock *)msk, &local, &remote);
spin_lock_bh(&msk->pm.lock);
+
+ mptcp_pm_announce_addr(msk, &remote, true);
}

void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 837e01057544..ba253a6947b0 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -169,6 +169,7 @@ struct mptcp_pm_data {
bool work_pending;
bool accept_addr;
bool accept_subflow;
+ bool add_addr_echo;
u8 add_addr_signaled;
u8 add_addr_accepted;
u8 local_addr_used;
@@ -442,7 +443,8 @@ void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);

int mptcp_pm_announce_addr(struct mptcp_sock *msk,
- const struct mptcp_addr_info *addr);
+ const struct mptcp_addr_info *addr,
+ bool echo);
int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 remote_id);

@@ -464,7 +466,7 @@ static inline unsigned int mptcp_add_addr_len(int family)
}

bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
- struct mptcp_addr_info *saddr);
+ struct mptcp_addr_info *saddr, bool *echo);
bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
u8 *rm_id);
int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
--
2.17.1