diff options
| author | Florian Westphal <fw@strlen.de> | 2020-07-30 21:25:51 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-07-31 16:55:32 -0700 |
| commit | 535fb8152f313dd5d30ef84ce55b01ad9cbae3cf (patch) | |
| tree | 600749f9200f86e9ba72ffb2063b48dc32a5e4a7 /net | |
| parent | f8ace8d915b88bd1bbaac695de94650dbb25c7b4 (diff) | |
| download | lwn-535fb8152f313dd5d30ef84ce55b01ad9cbae3cf.tar.gz lwn-535fb8152f313dd5d30ef84ce55b01ad9cbae3cf.zip | |
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: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mptcp/subflow.c | 9 | ||||
| -rw-r--r-- | 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 @@ again: 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); |