From: Florian Westphal <fw@strlen.de>
To: <netdev@vger.kernel.org>
Cc: edumazet@google.com, mathew.j.martineau@linux.intel.com,
matthieu.baerts@tessares.net, pabeni@redhat.com,
Florian Westphal <fw@strlen.de>
Subject: [PATCH v2 net-next 2/9] mptcp: token: move retry to caller
Date: Thu, 30 Jul 2020 21:25:51 +0200 [thread overview]
Message-ID: <20200730192558.25697-3-fw@strlen.de> (raw)
In-Reply-To: <20200730192558.25697-1-fw@strlen.de>
Once syncookie support is added, no state will be stored anymore when the
syn/ack is generated in syncookie mode.
When the ACK comes back, the generated key will be taken from the TCP ACK,
the token is re-generated and inserted into the token tree.
This means we can't retry with a new key when the token is already taken
in the syncookie case.
Therefore, move the retry logic to the caller to prepare for syncookie
support in mptcp.
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/mptcp/subflow.c | 9 ++++++++-
net/mptcp/token.c | 12 ++++--------
2 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 1c8482bc2ce5..9feb87880d1c 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -126,11 +126,18 @@ static void subflow_init_req(struct request_sock *req,
}
if (mp_opt.mp_capable && listener->request_mptcp) {
- int err;
+ int err, retries = 4;
+
+again:
+ do {
+ get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key));
+ } while (subflow_req->local_key == 0);
err = mptcp_token_new_request(req);
if (err == 0)
subflow_req->mp_capable = 1;
+ else if (retries-- > 0)
+ goto again;
subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
} else if (mp_opt.mp_join && listener->request_mptcp) {
diff --git a/net/mptcp/token.c b/net/mptcp/token.c
index 97cfc45bcc4f..f82410c54653 100644
--- a/net/mptcp/token.c
+++ b/net/mptcp/token.c
@@ -109,14 +109,12 @@ static void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
int mptcp_token_new_request(struct request_sock *req)
{
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
- int retries = TOKEN_MAX_RETRIES;
struct token_bucket *bucket;
u32 token;
-again:
- mptcp_crypto_key_gen_sha(&subflow_req->local_key,
- &subflow_req->token,
- &subflow_req->idsn);
+ mptcp_crypto_key_sha(subflow_req->local_key,
+ &subflow_req->token,
+ &subflow_req->idsn);
pr_debug("req=%p local_key=%llu, token=%u, idsn=%llu\n",
req, subflow_req->local_key, subflow_req->token,
subflow_req->idsn);
@@ -126,9 +124,7 @@ int mptcp_token_new_request(struct request_sock *req)
spin_lock_bh(&bucket->lock);
if (__token_bucket_busy(bucket, token)) {
spin_unlock_bh(&bucket->lock);
- if (!--retries)
- return -EBUSY;
- goto again;
+ return -EBUSY;
}
hlist_nulls_add_head_rcu(&subflow_req->token_node, &bucket->req_chain);
--
2.26.2
next prev parent reply other threads:[~2020-07-30 19:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 19:25 [PATCH v2 net-next 0/9] mptcp: add syncookie support Florian Westphal
2020-07-30 19:25 ` [PATCH v2 net-next 1/9] tcp: rename request_sock cookie_ts bit to syncookie Florian Westphal
2020-07-30 19:25 ` Florian Westphal [this message]
2020-07-31 22:37 ` [PATCH v2 net-next 2/9] mptcp: token: move retry to caller Mat Martineau
2020-07-30 19:25 ` [PATCH v2 net-next 3/9] mptcp: subflow: split subflow_init_req Florian Westphal
2020-07-31 22:37 ` Mat Martineau
2020-07-30 19:25 ` [PATCH v2 net-next 4/9] mptcp: rename and export mptcp_subflow_request_sock_ops Florian Westphal
2020-07-31 22:38 ` Mat Martineau
2020-07-30 19:25 ` [PATCH v2 net-next 5/9] mptcp: subflow: add mptcp_subflow_init_cookie_req helper Florian Westphal
2020-07-31 22:38 ` Mat Martineau
2020-07-30 19:25 ` [PATCH v2 net-next 6/9] tcp: syncookies: create mptcp request socket for ACK cookies with MPTCP option Florian Westphal
2020-07-30 19:25 ` [PATCH v2 net-next 7/9] mptcp: enable JOIN requests even if cookies are in use Florian Westphal
2020-07-31 22:39 ` Mat Martineau
2020-08-01 1:50 ` Eric Dumazet
2020-07-30 19:25 ` [PATCH v2 net-next 8/9] selftests: mptcp: make 2nd net namespace use tcp syn cookies unconditionally Florian Westphal
2020-07-31 22:39 ` Mat Martineau
2020-07-30 19:25 ` [PATCH v2 net-next 9/9] selftests: mptcp: add test cases for mptcp join tests with syn cookies Florian Westphal
2020-07-31 22:39 ` Mat Martineau
2020-07-31 23:56 ` [PATCH v2 net-next 0/9] mptcp: add syncookie support David Miller
2020-08-01 1:55 ` Eric Dumazet
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