1:06 a.m.
Send a DATA_FIN along with any subflow TCP FIN flag.
This seems to expose a bug in either the receive side disconnect
handling or the mptcp_connect test program. The self test has
intermittent problems with the receive temp file being truncated.
Signed-off-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
---
I've tested this commit when applied to the end of the export branch,
but I have not yet applied or tested it earlier in the history with the
"initial feature set" patches.
net/mptcp/options.c | 38 +++++++++++++++++++++++++++++++++++---
net/mptcp/subflow.c | 32 ++++++++++++++++++--------------
2 files changed, 53 insertions(+), 17 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 9a18a3670cdf..79890b96afeb 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -384,18 +384,47 @@ static bool mptcp_established_options_mp(struct sock *sk, unsigned
int *size,
return false;
}
+static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
+ struct mptcp_ext *ext)
+{
+ WARN_ONCE(!subflow->conn, "MPTCP: Missing MPTCP socket information");
+
+ /* Only send DATA_FIN if all data has been sent or this is the last
+ * mapping.
+ */
+ ext->data_fin = 1;
+
+ if (!ext->use_map) {
+ ext->use_map = 1;
+ ext->dsn64 = 1;
+ ext->data_seq = mptcp_sk(subflow->conn)->write_seq;
+ ext->subflow_seq = 0;
+ ext->data_len = 1;
+ } else {
+ ext->data_len++;
+ }
+}
+
static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
unsigned int *size,
unsigned int remaining,
struct mptcp_out_options *opts)
{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
unsigned int dss_size = 0;
struct mptcp_ext *mpext;
unsigned int ack_size;
+ u8 tcp_fin;
- mpext = skb ? mptcp_get_ext(skb) : NULL;
+ if (skb) {
+ mpext = mptcp_get_ext(skb);
+ tcp_fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
+ } else {
+ mpext = NULL;
+ tcp_fin = 0;
+ }
- if (!skb || (mpext && mpext->use_map)) {
+ if (!skb || (mpext && mpext->use_map) || tcp_fin) {
unsigned int map_size;
map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
@@ -405,6 +434,9 @@ static bool mptcp_established_options_dss(struct sock *sk, struct
sk_buff *skb,
dss_size = map_size;
if (mpext)
opts->ext_copy = *mpext;
+
+ if (skb && tcp_fin)
+ mptcp_write_data_fin(subflow, &opts->ext_copy);
} else {
opts->ext_copy.use_map = 0;
WARN_ONCE(1, "MPTCP: Map dropped");
@@ -422,7 +454,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct
sk_buff *skb,
dss_size += ack_size;
- msk = mptcp_sk(mptcp_subflow_ctx(sk)->conn);
+ msk = mptcp_sk(subflow->conn);
if (msk) {
opts->ext_copy.data_ack = msk->ack_seq;
} else {
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ff38d54392cd..f6f4dbf2dbab 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -422,6 +422,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct mptcp_ext *mpext;
struct sk_buff *skb;
+ u16 data_len;
u64 map_seq;
skb = skb_peek(&ssk->sk_receive_queue);
@@ -446,26 +447,29 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
if (!subflow->map_valid)
return MAPPING_INVALID;
+
goto validate_seq;
}
- pr_debug("seq=%llu is64=%d ssn=%u data_len=%u", mpext->data_seq,
- mpext->dsn64, mpext->subflow_seq, mpext->data_len);
+ pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d",
+ mpext->data_seq, mpext->dsn64, mpext->subflow_seq,
+ mpext->data_len, mpext->data_fin);
- if (mpext->data_len == 0) {
+ data_len = mpext->data_len;
+ if (data_len == 0) {
pr_err("Infinite mapping not handled");
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
return MAPPING_INVALID;
- } else if (mpext->subflow_seq == 0 &&
- mpext->data_fin == 1) {
- if (WARN_ON_ONCE(mpext->data_len != 1))
- return false;
+ }
- /* do not try hard to handle this any better, till we have
- * real data_fin support
- */
- pr_debug("DATA_FIN with no payload");
- return MAPPING_DATA_FIN;
+ if (mpext->data_fin == 1) {
+ if (data_len == 1) {
+ pr_debug("DATA_FIN with no payload");
+ return MAPPING_DATA_FIN;
+ }
+
+ /* Adjust for DATA_FIN using 1 byte of sequence space */
+ data_len--;
}
if (!mpext->dsn64) {
@@ -480,7 +484,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
/* Allow replacing only with an identical map */
if (subflow->map_seq == map_seq &&
subflow->map_subflow_seq == mpext->subflow_seq &&
- subflow->map_data_len == mpext->data_len) {
+ subflow->map_data_len == data_len) {
skb_ext_del(skb, SKB_EXT_MPTCP);
return MAPPING_OK;
}
@@ -499,7 +503,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
subflow->map_seq = map_seq;
subflow->map_subflow_seq = mpext->subflow_seq;
- subflow->map_data_len = mpext->data_len;
+ subflow->map_data_len = data_len;
subflow->map_valid = 1;
pr_debug("new map seq=%llu subflow_seq=%u data_len=%u",
subflow->map_seq, subflow->map_subflow_seq,
--
2.24.0
5:37 a.m.
Hi Mat,
On 14/11/2019 07:06, Mat Martineau wrote:
Send a DATA_FIN along with any subflow TCP FIN flag.
This seems to expose a bug in either the receive side disconnect
handling or the mptcp_connect test program. The self test has
intermittent problems with the receive temp file being truncated.
Signed-off-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
Thank you for the patch!
---
I've tested this commit when applied to the end of the export branch,
but I have not yet applied or tested it earlier in the history with the
"initial feature set" patches.
Good point :)
net/mptcp/options.c | 38 +++++++++++++++++++++++++++++++++++---
net/mptcp/subflow.c | 32 ++++++++++++++++++--------------
2 files changed, 53 insertions(+), 17 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 9a18a3670cdf..79890b96afeb 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -384,18 +384,47 @@ static bool mptcp_established_options_mp(struct sock *sk, unsigned
int *size,
return false;
}
+static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
+ struct mptcp_ext *ext)
+{
+ WARN_ONCE(!subflow->conn, "MPTCP: Missing MPTCP socket information");
I guess that if you think the WARN is needed, maybe safer to also return
earlier, not to use "subflow->conn" later on if !ext->use_map.
+ /* Only send DATA_FIN if all data has been sent or this is the
last
+ * mapping.
Maybe it is just me but the comment looks confusing when placed here:
for me, starting it with "Only" means that we have a "if" statement
just
after.
+ */
+ ext->data_fin = 1;
+
+ if (!ext->use_map) {
+ ext->use_map = 1;
+ ext->dsn64 = 1;
+ ext->data_seq = mptcp_sk(subflow->conn)->write_seq;
+ ext->subflow_seq = 0;
+ ext->data_len = 1;
+ } else {
+ ext->data_len++;
+ }
+}
+
static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
unsigned int *size,
unsigned int remaining,
struct mptcp_out_options *opts)
{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
unsigned int dss_size = 0;
struct mptcp_ext *mpext;
unsigned int ack_size;
+ u8 tcp_fin;
Detail: could we use a "boolean" type here?
- mpext = skb ? mptcp_get_ext(skb) : NULL;
+ if (skb) {
+ mpext = mptcp_get_ext(skb);
+ tcp_fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
+ } else {
+ mpext = NULL;
+ tcp_fin = 0;
+ }
- if (!skb || (mpext && mpext->use_map)) {
+ if (!skb || (mpext && mpext->use_map) || tcp_fin) {
unsigned int map_size;
map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
@@ -405,6 +434,9 @@ static bool mptcp_established_options_dss(struct sock *sk, struct
sk_buff *skb,
dss_size = map_size;
if (mpext)
opts->ext_copy = *mpext;
+
+ if (skb && tcp_fin)
As discussed at the meeting yesterday, may you also check that it is the
last subflow please?
+ mptcp_write_data_fin(subflow, &opts->ext_copy);
} else {
opts->ext_copy.use_map = 0;
WARN_ONCE(1, "MPTCP: Map dropped");
@@ -422,7 +454,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct
sk_buff *skb,
dss_size += ack_size;
- msk = mptcp_sk(mptcp_subflow_ctx(sk)->conn);
+ msk = mptcp_sk(subflow->conn);
if (msk) {
opts->ext_copy.data_ack = msk->ack_seq;
} else {
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ff38d54392cd..f6f4dbf2dbab 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -422,6 +422,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct mptcp_ext *mpext;
struct sk_buff *skb;
+ u16 data_len;
u64 map_seq;
skb = skb_peek(&ssk->sk_receive_queue);
@@ -446,26 +447,29 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
if (!subflow->map_valid)
return MAPPING_INVALID;
+
goto validate_seq;
}
- pr_debug("seq=%llu is64=%d ssn=%u data_len=%u", mpext->data_seq,
- mpext->dsn64, mpext->subflow_seq, mpext->data_len);
+ pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d",
+ mpext->data_seq, mpext->dsn64, mpext->subflow_seq,
+ mpext->data_len, mpext->data_fin);
- if (mpext->data_len == 0) {
+ data_len = mpext->data_len;
+ if (data_len == 0) {
pr_err("Infinite mapping not handled");
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
return MAPPING_INVALID;
- } else if (mpext->subflow_seq == 0 &&
- mpext->data_fin == 1) {
- if (WARN_ON_ONCE(mpext->data_len != 1))
- return false;
+ }
- /* do not try hard to handle this any better, till we have
- * real data_fin support
- */
- pr_debug("DATA_FIN with no payload");
- return MAPPING_DATA_FIN;
+ if (mpext->data_fin == 1) {
+ if (data_len == 1) {
+ pr_debug("DATA_FIN with no payload"); > + return MAPPING_DATA_FIN;>
+ }
+
+ /* Adjust for DATA_FIN using 1 byte of sequence space */
+ data_len--;
Is it because here we cannot add the DATA_FIN bit yet, still more data
to send?
Cheers,
Matt
--
Matthieu Baerts | R&D Engineer
matthieu.baerts(a)tessares.net
Tessares SA | Hybrid Access Solutions
www.tessares.net
1 Avenue Jean Monnet, 1348 Louvain-la-Neuve, Belgium
2:27 p.m.
On Fri, 15 Nov 2019, Matthieu Baerts wrote:
Hi Mat,
On 14/11/2019 07:06, Mat Martineau wrote:
> Send a DATA_FIN along with any subflow TCP FIN flag.
>
> This seems to expose a bug in either the receive side disconnect
> handling or the mptcp_connect test program. The self test has
> intermittent problems with the receive temp file being truncated.
>
> Signed-off-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
Thank you for the patch!
> ---
>
> I've tested this commit when applied to the end of the export branch,
> but I have not yet applied or tested it earlier in the history with the
> "initial feature set" patches.
Good point :)
> net/mptcp/options.c | 38 +++++++++++++++++++++++++++++++++++---
> net/mptcp/subflow.c | 32 ++++++++++++++++++--------------
> 2 files changed, 53 insertions(+), 17 deletions(-)
>
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index 9a18a3670cdf..79890b96afeb 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -384,18 +384,47 @@ static bool mptcp_established_options_mp(struct sock
> *sk, unsigned int *size,
> return false;
> }
> +static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
> + struct mptcp_ext *ext)
> +{
> + WARN_ONCE(!subflow->conn, "MPTCP: Missing MPTCP socket information");
I guess that if you think the WARN is needed, maybe safer to also return
earlier, not to use "subflow->conn" later on if !ext->use_map.
I had this included as a paranoid debugging check for development. I
should have dropped it, and looking around at other code it looks like
subflow->conn is always set.
> + /* Only send DATA_FIN if all data has been sent or this is the last
> + * mapping.
Maybe it is just me but the comment looks confusing when placed here: for me,
starting it with "Only" means that we have a "if" statement just
after.
Good point, this carried over from some code that did have that 'if'. Will
fix.
> + */
> + ext->data_fin = 1;
> +
> + if (!ext->use_map) {
> + ext->use_map = 1;
> + ext->dsn64 = 1;
> + ext->data_seq = mptcp_sk(subflow->conn)->write_seq;
> + ext->subflow_seq = 0;
> + ext->data_len = 1;
> + } else {
> + ext->data_len++;
> + }
> +}
> +
> static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff
> *skb,
> unsigned int *size,
> unsigned int remaining,
> struct mptcp_out_options *opts)
> {
> + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
> unsigned int dss_size = 0;
> struct mptcp_ext *mpext;
> unsigned int ack_size;
> + u8 tcp_fin;
Detail: could we use a "boolean" type here?
I did consider that when writing it. With bool, I'd want to use "tcp_fin =
!!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)" below. It seemed cleaner to
match the type of tcp_flags and skip the !! stuff.
(it does happen that TCPHDR_FIN is 0x01 so there's not much difference to
the compiler)
> - mpext = skb ? mptcp_get_ext(skb) : NULL;
> + if (skb) {
> + mpext = mptcp_get_ext(skb);
> + tcp_fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
> + } else {
> + mpext = NULL;
> + tcp_fin = 0;
> + }
> - if (!skb || (mpext && mpext->use_map)) {
> + if (!skb || (mpext && mpext->use_map) || tcp_fin) {
> unsigned int map_size;
> map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
> @@ -405,6 +434,9 @@ static bool mptcp_established_options_dss(struct sock
> *sk, struct sk_buff *skb,
> dss_size = map_size;
> if (mpext)
> opts->ext_copy = *mpext;
> +
> + if (skb && tcp_fin)
As discussed at the meeting yesterday, may you also check that it is the last
subflow please?
Yes - although I think determining the "last subflow" is more complicated
than looking at the length of the conn list. We don't want DATA_FIN if one
subflow is closing and others are staying open, but DATA_FIN is desired of
all subflows are closing at the same time.
> + mptcp_write_data_fin(subflow,
> &opts->ext_copy);
> } else {
> opts->ext_copy.use_map = 0;
> WARN_ONCE(1, "MPTCP: Map dropped");
> @@ -422,7 +454,7 @@ static bool mptcp_established_options_dss(struct sock
> *sk, struct sk_buff *skb,
> dss_size += ack_size;
> - msk = mptcp_sk(mptcp_subflow_ctx(sk)->conn);
> + msk = mptcp_sk(subflow->conn);
> if (msk) {
> opts->ext_copy.data_ack = msk->ack_seq;
> } else {
> diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
> index ff38d54392cd..f6f4dbf2dbab 100644
> --- a/net/mptcp/subflow.c
> +++ b/net/mptcp/subflow.c
> @@ -422,6 +422,7 @@ static enum mapping_status get_mapping_status(struct
> sock *ssk)
> struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
> struct mptcp_ext *mpext;
> struct sk_buff *skb;
> + u16 data_len;
> u64 map_seq;
> skb = skb_peek(&ssk->sk_receive_queue);
> @@ -446,26 +447,29 @@ static enum mapping_status get_mapping_status(struct
> sock *ssk)
> if (!subflow->map_valid)
> return MAPPING_INVALID;
> +
> goto validate_seq;
> }
> - pr_debug("seq=%llu is64=%d ssn=%u data_len=%u", mpext->data_seq,
> - mpext->dsn64, mpext->subflow_seq, mpext->data_len);
> + pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d",
> + mpext->data_seq, mpext->dsn64, mpext->subflow_seq,
> + mpext->data_len, mpext->data_fin);
> - if (mpext->data_len == 0) {
> + data_len = mpext->data_len;
> + if (data_len == 0) {
> pr_err("Infinite mapping not handled");
> MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
> return MAPPING_INVALID;
> - } else if (mpext->subflow_seq == 0 &&
> - mpext->data_fin == 1) {
> - if (WARN_ON_ONCE(mpext->data_len != 1))
> - return false;
> + }
> - /* do not try hard to handle this any better, till we have
> - * real data_fin support
> - */
> - pr_debug("DATA_FIN with no payload");
> - return MAPPING_DATA_FIN;
> + if (mpext->data_fin == 1) {
> + if (data_len == 1) {
> + pr_debug("DATA_FIN with no payload"); > +
> return MAPPING_DATA_FIN;> + }
> +
> + /* Adjust for DATA_FIN using 1 byte of sequence space */
> + data_len--;
Is it because here we cannot add the DATA_FIN bit yet, still more data to
send?
This is on the receive side to adjust the mapping to reflect the actual
data payload that is in the skbs. The DATA_FIN received from the peer
consumes a byte of MPTCP-level sequence space even though there is no
corresponding skb data payload for the reassembly code to look for.
When DATA_FIN is sent in a packet with data payload, the DSS
mapping is extended by 1 in mptcp_write_data_fin() (look for
"ext->data_len++" above), so this line of code is restoring the original
mapping for reassembly purposes.
--
Mat Martineau
Intel
468
days inactive
469
days old
2 comments
2 participants
participants (2)
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Matthieu Baerts