* [MPTCP] [PATCH net] net: mptcp: make DACK4/DACK8 usage consistent among all subflows
@ 2020-10-06 12:22 Davide Caratti
0 siblings, 0 replies; 2+ messages in thread
From: Davide Caratti @ 2020-10-06 12:22 UTC (permalink / raw)
To: mptcp
[-- Attachment #1: Type: text/plain, Size: 2575 bytes --]
using packetdrill it's possible to observe the same MPTCP DSN being acked
by different subflows with DACK4 and DACK8. This is in contrast with what
specified in RFC8684 §3.3.2: if an MPTCP endpoint transmits a 64-bit wide
DSN, it MUST be acknowledged with a 64-bit wide DACK. Fix 'use_64bit_ack'
variable to make it a property of MPTCP sockets, not TCP subflows.
Fixes: a0c1d0eafd1e ("mptcp: Use 32-bit DATA_ACK when possible")
Signed-off-by: Davide Caratti <dcaratti(a)redhat.com>
---
net/mptcp/options.c | 2 +-
net/mptcp/protocol.h | 2 +-
net/mptcp/subflow.c | 3 +--
3 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index fc9e114ba1e3..d601dd1ebe5e 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -517,7 +517,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
return ret;
}
- if (subflow->use_64bit_ack) {
+ if (READ_ONCE(msk->use_64bit_ack)) {
ack_size = TCPOLEN_MPTCP_DSS_ACK64;
opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
opts->ext_copy.ack64 = 1;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index c131810adf42..746413ab4f18 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -222,6 +222,7 @@ struct mptcp_sock {
bool fully_established;
bool rcv_data_fin;
bool snd_data_fin_enable;
+ bool use_64bit_ack; /* Set when we received a 64-bit DSN */
spinlock_t join_list_lock;
struct work_struct work;
struct sk_buff *ooo_last_skb;
@@ -352,7 +353,6 @@ struct mptcp_subflow_context {
mpc_map : 1,
backup : 1,
rx_eof : 1,
- use_64bit_ack : 1, /* Set when we received a 64-bit DSN */
can_ack : 1, /* only after processing the remote a key */
disposable : 1; /* ctx can be free at ulp release time */
enum mptcp_data_avail data_avail;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ae5fa5b3d42b..00040dee323e 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -770,12 +770,11 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
if (!mpext->dsn64) {
map_seq = expand_seq(subflow->map_seq, subflow->map_data_len,
mpext->data_seq);
- subflow->use_64bit_ack = 0;
pr_debug("expanded seq=%llu", subflow->map_seq);
} else {
map_seq = mpext->data_seq;
- subflow->use_64bit_ack = 1;
}
+ WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
if (subflow->map_valid) {
/* Allow replacing only with an identical map */
--
2.26.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [MPTCP] [PATCH net] net: mptcp: make DACK4/DACK8 usage consistent among all subflows
@ 2020-10-06 16:26 Davide Caratti
0 siblings, 0 replies; 2+ messages in thread
From: Davide Caratti @ 2020-10-06 16:26 UTC (permalink / raw)
To: mptcp
[-- Attachment #1: Type: text/plain, Size: 2549 bytes --]
using packetdrill it's possible to observe the same MPTCP DSN being acked
by different subflows with DACK4 and DACK8. This is in contrast with what
specified in RFC8684 §3.3.2: if an MPTCP endpoint transmits a 64-bit wide
DSN, it MUST be acknowledged with a 64-bit wide DACK. Fix 'use_64bit_ack'
variable to make it a property of MPTCP sockets, not TCP subflows.
Fixes: a0c1d0eafd1e ("mptcp: Use 32-bit DATA_ACK when possible")
Acked-by: Paolo Abeni <pabeni(a)redhat.com>
Signed-off-by: Davide Caratti <dcaratti(a)redhat.com>
---
net/mptcp/options.c | 2 +-
net/mptcp/protocol.h | 2 +-
net/mptcp/subflow.c | 3 +--
3 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 888bbbbb3e8a..9d7fa93fe0cf 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -516,7 +516,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
return ret;
}
- if (subflow->use_64bit_ack) {
+ if (READ_ONCE(msk->use_64bit_ack)) {
ack_size = TCPOLEN_MPTCP_DSS_ACK64;
opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
opts->ext_copy.ack64 = 1;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 20f04ac85409..285dd8b2b43a 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -202,6 +202,7 @@ struct mptcp_sock {
bool fully_established;
bool rcv_data_fin;
bool snd_data_fin_enable;
+ bool use_64bit_ack; /* Set when we received a 64-bit DSN */
spinlock_t join_list_lock;
struct work_struct work;
struct list_head conn_list;
@@ -294,7 +295,6 @@ struct mptcp_subflow_context {
backup : 1,
data_avail : 1,
rx_eof : 1,
- use_64bit_ack : 1, /* Set when we received a 64-bit DSN */
can_ack : 1; /* only after processing the remote a key */
u32 remote_nonce;
u64 thmac;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 6f035af1c9d2..91bef7bfffa6 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -769,12 +769,11 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
if (!mpext->dsn64) {
map_seq = expand_seq(subflow->map_seq, subflow->map_data_len,
mpext->data_seq);
- subflow->use_64bit_ack = 0;
pr_debug("expanded seq=%llu", subflow->map_seq);
} else {
map_seq = mpext->data_seq;
- subflow->use_64bit_ack = 1;
}
+ WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
if (subflow->map_valid) {
/* Allow replacing only with an identical map */
--
2.26.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
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