Commit 535fb815 authored by Florian Westphal's avatar Florian Westphal Committed by David S. Miller
Browse files

mptcp: token: move retry to caller 



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: default avatarFlorian Westphal <fw@strlen.de>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f8ace8d9

net/mptcp/subflow.c

+8 −1
Original line number Diff line number Diff line
@@ -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) {

net/mptcp/token.c

+4 −8
Original line number Diff line number Diff line
@@ -109,12 +109,10 @@ 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,

	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",
@@ -126,9 +124,7 @@ again: 
	spin_lock_bh(&bucket->lock);

	if (__token_bucket_busy(bucket, token)) {

		spin_unlock_bh(&bucket->lock);

		if (!--retries)

		return -EBUSY;

		goto again;

	}



	hlist_nulls_add_head_rcu(&subflow_req->token_node, &bucket->req_chain);

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