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| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2008-09-25 17:05:50 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2008-09-25 17:05:50 +0200 |
| commit | 3863f882469117afd6a2ad7ce25711b619f43b27 (patch) | |
| tree | 11e0242047872b1332cd491f8b8c6c1ca5e451ac | |
| parent | 666ceb1e2cd71f844f5794a556c46b114764bca6 (diff) | |
| download | conntrack-tools-3863f882469117afd6a2ad7ce25711b619f43b27.tar.gz conntrack-tools-3863f882469117afd6a2ad7ce25711b619f43b27.zip | |
ftfw: fix race that triggers a double insertion into tx_list
This patch fixes a race condition that can trigger a double
insertion to the tx_list. This happens if we receive two resync
request very close or resync just after a nack or vice-versa.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | src/sync-ftfw.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/sync-ftfw.c b/src/sync-ftfw.c index 4c1b536..8dd5554 100644 --- a/src/sync-ftfw.c +++ b/src/sync-ftfw.c @@ -196,6 +196,10 @@ static int do_cache_to_tx(void *data1, void *data2) struct us_conntrack *u = data2; struct cache_ftfw *cn = cache_get_extra(STATE_SYNC(internal), u); + /* repeated request for resync? */ + if (!list_empty(&cn->tx_list)) + return 0; + /* add to tx list */ list_add_tail(&cn->tx_list, &tx_list); tx_list_len++; @@ -264,8 +268,11 @@ static void rs_list_to_tx(struct cache *c, unsigned int from, unsigned int to) dp("resending nack'ed (oldseq=%u)\n", cn->seq); list_del_init(&cn->rs_list); rs_list_len--; - list_add_tail(&cn->tx_list, &tx_list); - tx_list_len++; + /* we received a request for resync before this nack? */ + if (list_empty(&cn->tx_list)) { + list_add_tail(&cn->tx_list, &tx_list); + tx_list_len++; + } write_evfd(STATE_SYNC(evfd)); } } |