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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-07-19 13:44:17 +0400 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2011-07-19 13:44:17 +0400 |
| commit | 5863702a3421b0d2a63a473cf96afeb9fe09070d (patch) | |
| tree | d462b775b7702a4ae44ec50ec28a2217d5ab2338 /net | |
| parent | 84a797dd0b9f7130357b70577fcbda8e638c71a7 (diff) | |
| download | linux-5863702a3421b0d2a63a473cf96afeb9fe09070d.tar.xz | |
netfilter: nfnetlink_queue: assert monotonic packet ids
Packet identifier is currently setup in nfqnl_build_packet_message(),
using one atomic_inc_return().
Problem is that since several cpus might concurrently call
nfqnl_enqueue_packet() for the same queue, we can deliver packets to
consumer in non monotonic way (packet N+1 being delivered after packet
N)
This patch moves the packet id setup from nfqnl_build_packet_message()
to nfqnl_enqueue_packet() to guarantee correct delivery order.
This also removes one atomic operation.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Florian Westphal <fw@strlen.de>
CC: Pablo Neira Ayuso <pablo@netfilter.org>
CC: Eric Leblond <eric@regit.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nfnetlink_queue.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index c645b87915b8..3b2af8cb7de9 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -58,7 +58,7 @@ struct nfqnl_instance { */ spinlock_t lock; unsigned int queue_total; - atomic_t id_sequence; /* 'sequence' of pkt ids */ + unsigned int id_sequence; /* 'sequence' of pkt ids */ struct list_head queue_list; /* packets in queue */ }; @@ -213,13 +213,15 @@ nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data) static struct sk_buff * nfqnl_build_packet_message(struct nfqnl_instance *queue, - struct nf_queue_entry *entry) + struct nf_queue_entry *entry, + __be32 **packet_id_ptr) { sk_buff_data_t old_tail; size_t size; size_t data_len = 0; struct sk_buff *skb; - struct nfqnl_msg_packet_hdr pmsg; + struct nlattr *nla; + struct nfqnl_msg_packet_hdr *pmsg; struct nlmsghdr *nlh; struct nfgenmsg *nfmsg; struct sk_buff *entskb = entry->skb; @@ -272,12 +274,11 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue, nfmsg->version = NFNETLINK_V0; nfmsg->res_id = htons(queue->queue_num); - entry->id = atomic_inc_return(&queue->id_sequence); - pmsg.packet_id = htonl(entry->id); - pmsg.hw_protocol = entskb->protocol; - pmsg.hook = entry->hook; - - NLA_PUT(skb, NFQA_PACKET_HDR, sizeof(pmsg), &pmsg); + nla = __nla_reserve(skb, NFQA_PACKET_HDR, sizeof(*pmsg)); + pmsg = nla_data(nla); + pmsg->hw_protocol = entskb->protocol; + pmsg->hook = entry->hook; + *packet_id_ptr = &pmsg->packet_id; indev = entry->indev; if (indev) { @@ -388,6 +389,7 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) struct sk_buff *nskb; struct nfqnl_instance *queue; int err = -ENOBUFS; + __be32 *packet_id_ptr; /* rcu_read_lock()ed by nf_hook_slow() */ queue = instance_lookup(queuenum); @@ -401,7 +403,7 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) goto err_out; } - nskb = nfqnl_build_packet_message(queue, entry); + nskb = nfqnl_build_packet_message(queue, entry, &packet_id_ptr); if (nskb == NULL) { err = -ENOMEM; goto err_out; @@ -420,6 +422,8 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) queue->queue_total); goto err_out_free_nskb; } + entry->id = ++queue->id_sequence; + *packet_id_ptr = htonl(entry->id); /* nfnetlink_unicast will either free the nskb or add it to a socket */ err = nfnetlink_unicast(nskb, &init_net, queue->peer_pid, MSG_DONTWAIT); @@ -852,7 +856,7 @@ static int seq_show(struct seq_file *s, void *v) inst->peer_pid, inst->queue_total, inst->copy_mode, inst->copy_range, inst->queue_dropped, inst->queue_user_dropped, - atomic_read(&inst->id_sequence), 1); + inst->id_sequence, 1); } static const struct seq_operations nfqnl_seq_ops = { |