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netfilter: nfnetlink_queue: add skb info attribute 

Once we allow userspace to receive gso/gro packets, userspace
needs to be able to determine when checksums appear to be
broken, but are not.

NFQA_SKB_CSUMNOTREADY means 'checksums will be fixed in kernel
later, pretend they are ok'.

NFQA_SKB_GSO could be used for statistics, or to determine when
packet size exceeds mtu.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2013-04-19 04:58:26 +00:00 committed by Pablo Neira Ayuso
parent a5fedd43d5
commit 7237190df8
2 changed files with 23 additions and 0 deletions
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7
include/uapi/linux/netfilter/nfnetlink_queue.h
View File

@ -45,6 +45,7 @@ enum nfqnl_attr_type {
NFQA_CT, /* nf_conntrack_netlink.h */
NFQA_CT_INFO, /* enum ip_conntrack_info */
NFQA_CAP_LEN, /* __u32 length of captured packet */
NFQA_SKB_INFO, /* __u32 skb meta information */
__NFQA_MAX
};
@ -98,4 +99,10 @@ enum nfqnl_attr_config {
#define NFQA_CFG_F_CONNTRACK (1 << 1)
#define NFQA_CFG_F_MAX (1 << 2)
/* flags for NFQA_SKB_INFO */
/* packet appears to have wrong checksums, but they are ok */
#define NFQA_SKB_CSUMNOTREADY (1 << 0)
/* packet is GSO (i.e., exceeds device mtu) */
#define NFQA_SKB_GSO (1 << 1)
#endif /* _NFNETLINK_QUEUE_H */

16
net/netfilter/nfnetlink_queue_core.c
View File

@ -272,6 +272,18 @@ nfqnl_zcopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
skb_shinfo(to)->nr_frags = j;
}
static int nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet)
{
__u32 flags = 0;
if (packet->ip_summed == CHECKSUM_PARTIAL)
flags = NFQA_SKB_CSUMNOTREADY;
if (skb_is_gso(packet))
flags |= NFQA_SKB_GSO;
return flags ? nla_put_be32(nlskb, NFQA_SKB_INFO, htonl(flags)) : 0;
}
static struct sk_buff *
nfqnl_build_packet_message(struct nfqnl_instance *queue,
struct nf_queue_entry *entry,
@ -301,6 +313,7 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
#endif
+ nla_total_size(sizeof(u_int32_t)) /* mark */
+ nla_total_size(sizeof(struct nfqnl_msg_packet_hw))
+ nla_total_size(sizeof(u_int32_t)) /* skbinfo */
+ nla_total_size(sizeof(u_int32_t)); /* cap_len */
if (entskb->tstamp.tv64)
@ -454,6 +467,9 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
if (cap_len > 0 && nla_put_be32(skb, NFQA_CAP_LEN, htonl(cap_len)))
goto nla_put_failure;
if (nfqnl_put_packet_info(skb, entskb))
goto nla_put_failure;
if (data_len) {
struct nlattr *nla;