From 9cefbbc9c8f9abe0bc514dcfca46e8051ee84050 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 4 Jun 2013 22:22:15 +0000 Subject: [PATCH] netfilter: nfnetlink_queue: cleanup copy_range usage For every packet queued, we check if configured copy_range is 0, and treat that as 'copy entire packet'. We can move this check to the queue configuration, and can set copy_range appropriately. Also, convert repetitive '0xffff - NLA_HDRLEN' to a macro. [ queue initialization still used 0xffff, although its harmless since the initial setting is overwritten on queue config ] Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_queue_core.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c index cff4449..3c42181 100644 --- a/net/netfilter/nfnetlink_queue_core.c +++ b/net/netfilter/nfnetlink_queue_core.c @@ -41,6 +41,14 @@ #define NFQNL_QMAX_DEFAULT 1024 +/* We're using struct nlattr which has 16bit nla_len. Note that nla_len + * includes the header length. Thus, the maximum packet length that we + * support is 65531 bytes. We send truncated packets if the specified length + * is larger than that. Userspace can check for presence of NFQA_CAP_LEN + * attribute to detect truncation. + */ +#define NFQNL_MAX_COPY_RANGE (0xffff - NLA_HDRLEN) + struct nfqnl_instance { struct hlist_node hlist; /* global list of queues */ struct rcu_head rcu; @@ -122,7 +130,7 @@ instance_create(struct nfnl_queue_net *q, u_int16_t queue_num, inst->queue_num = queue_num; inst->peer_portid = portid; inst->queue_maxlen = NFQNL_QMAX_DEFAULT; - inst->copy_range = 0xffff; + inst->copy_range = NFQNL_MAX_COPY_RANGE; inst->copy_mode = NFQNL_COPY_NONE; spin_lock_init(&inst->lock); INIT_LIST_HEAD(&inst->queue_list); @@ -333,10 +341,9 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue, return NULL; data_len = ACCESS_ONCE(queue->copy_range); - if (data_len == 0 || data_len > entskb->len) + if (data_len > entskb->len) data_len = entskb->len; - if (!entskb->head_frag || skb_headlen(entskb) < L1_CACHE_BYTES || skb_shinfo(entskb)->nr_frags >= MAX_SKB_FRAGS) @@ -727,13 +734,8 @@ nfqnl_set_mode(struct nfqnl_instance *queue, case NFQNL_COPY_PACKET: queue->copy_mode = mode; - /* We're using struct nlattr which has 16bit nla_len. Note that - * nla_len includes the header length. Thus, the maximum packet - * length that we support is 65531 bytes. We send truncated - * packets if the specified length is larger than that. - */ - if (range > 0xffff - NLA_HDRLEN) - queue->copy_range = 0xffff - NLA_HDRLEN; + if (range == 0 || range > NFQNL_MAX_COPY_RANGE) + queue->copy_range = NFQNL_MAX_COPY_RANGE; else queue->copy_range = range; break; -- 2.7.4