[PATCH lnf-queue] api: add nfq_nlmsg_get_timestamp helper

[PATCH lnf-queue] api: add nfq_nlmsg_get_timestamp helper

[Florian Westphal]

The NFQA_TIMESTAMP structure is in network byte order, so it seems
appropriate to add a helper to convert it to a timeval struct.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 examples/nf-queue.c                             |    9 ++++++++-
 include/libnetfilter_queue/libnetfilter_queue.h |    2 ++
 src/nlmsg.c                                     |   15 +++++++++++++++
 3 files changed, 25 insertions(+), 1 deletions(-)

diff --git a/examples/nf-queue.c b/examples/nf-queue.c
index 1f465ad..2722426 100644
--- a/examples/nf-queue.c
+++ b/examples/nf-queue.c
@@ -5,6 +5,7 @@
 #include <string.h>
 #include <time.h>
 #include <arpa/inet.h>
+#include <sys/time.h>
 
 #include <libmnl/libmnl.h>
 #include <linux/netfilter.h>
@@ -54,6 +55,7 @@ static int queue_cb(const struct nlmsghdr *nlh, void *data)
 	uint32_t id = 0, skbinfo;
 	struct nfgenmsg *nfg;
 	uint16_t plen;
+	struct timeval tv;
 
 	if (nfq_nlmsg_parse(nlh, attr) < 0) {
 		perror("problems parsing");
@@ -72,7 +74,11 @@ static int queue_cb(const struct nlmsghdr *nlh, void *data)
 	plen = mnl_attr_get_payload_len(attr[NFQA_PAYLOAD]);
 	/* void *payload = mnl_attr_get_payload(attr[NFQA_PAYLOAD]); */
 
-	skbinfo = attr[NFQA_SKB_INFO] ? ntohl(mnl_attr_get_u32(attr[NFQA_SKB_INFO])) : 0;
+	if (attr[NFQA_TIMESTAMP])
+		nfq_nlmsg_get_timestamp(attr[NFQA_TIMESTAMP], &tv);
+	else
+		gettimeofday(&tv, NULL);
+	printf("%lu:%06lu ", (long) tv.tv_sec, (long) tv.tv_usec);
 
 	if (attr[NFQA_CAP_LEN]) {
 		uint32_t orig_len = ntohl(mnl_attr_get_u32(attr[NFQA_CAP_LEN]));
@@ -80,6 +86,7 @@ static int queue_cb(const struct nlmsghdr *nlh, void *data)
 			printf("truncated ");
 	}
 
+	skbinfo = attr[NFQA_SKB_INFO] ? ntohl(mnl_attr_get_u32(attr[NFQA_SKB_INFO])) : 0;
 	if (skbinfo & NFQA_SKB_GSO)
 		printf("GSO ");
 
diff --git a/include/libnetfilter_queue/libnetfilter_queue.h b/include/libnetfilter_queue/libnetfilter_queue.h
index b9f16e2..537cabf 100644
--- a/include/libnetfilter_queue/libnetfilter_queue.h
+++ b/include/libnetfilter_queue/libnetfilter_queue.h
@@ -144,6 +144,8 @@ void nfq_nlmsg_verdict_put_pkt(struct nlmsghdr *nlh, const void *pkt, uint32_t p
 
 int nfq_nlmsg_parse(const struct nlmsghdr *nlh, struct nlattr **pkt);
 
+void nfq_nlmsg_get_timestamp(const struct nlattr *attr, struct timeval *tv);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/src/nlmsg.c b/src/nlmsg.c
index e7a30e0..10f96cf 100644
--- a/src/nlmsg.c
+++ b/src/nlmsg.c
@@ -172,5 +172,20 @@ int nfq_nlmsg_parse(const struct nlmsghdr *nlh, struct nlattr **attr)
 EXPORT_SYMBOL(nfq_nlmsg_parse);
 
 /**
+ * nfq_nlmsg_get_timestamp - get the packet timestamp
+ * \param attr pointer to valid NFQA_TIMESTAMP attribute header
+ * \param timeval structure to fill with data
+ *
+ * This function always succeeds.
+ */
+void nfq_nlmsg_get_timestamp(const struct nlattr *attr, struct timeval *tv)
+{
+	struct nfqnl_msg_packet_timestamp *ts = mnl_attr_get_payload(attr);
+	tv->tv_sec = __be64_to_cpu(ts->sec);
+	tv->tv_usec = __be64_to_cpu(ts->usec);
+}
+EXPORT_SYMBOL(nfq_nlmsg_get_timestamp);
+
+/**
  * @}
  */
-- 
1.7.8.6

Re: [PATCH lnf-queue] api: add nfq_nlmsg_get_timestamp helper

[Pablo Neira Ayuso]

Hi Florian,

On Thu, Aug 22, 2013 at 05:07:17PM +0200, Florian Westphal wrote:
> The NFQA_TIMESTAMP structure is in network byte order, so it seems
> appropriate to add a helper to convert it to a timeval struct.
> 
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  examples/nf-queue.c                             |    9 ++++++++-
>  include/libnetfilter_queue/libnetfilter_queue.h |    2 ++
>  src/nlmsg.c                                     |   15 +++++++++++++++
>  3 files changed, 25 insertions(+), 1 deletions(-)
> 
> diff --git a/examples/nf-queue.c b/examples/nf-queue.c
> index 1f465ad..2722426 100644
> --- a/examples/nf-queue.c
> +++ b/examples/nf-queue.c
> @@ -5,6 +5,7 @@
>  #include <string.h>
>  #include <time.h>
>  #include <arpa/inet.h>
> +#include <sys/time.h>
>  
>  #include <libmnl/libmnl.h>
>  #include <linux/netfilter.h>
> @@ -54,6 +55,7 @@ static int queue_cb(const struct nlmsghdr *nlh, void *data)
>  	uint32_t id = 0, skbinfo;
>  	struct nfgenmsg *nfg;
>  	uint16_t plen;
> +	struct timeval tv;
>  
>  	if (nfq_nlmsg_parse(nlh, attr) < 0) {
>  		perror("problems parsing");
> @@ -72,7 +74,11 @@ static int queue_cb(const struct nlmsghdr *nlh, void *data)
>  	plen = mnl_attr_get_payload_len(attr[NFQA_PAYLOAD]);
>  	/* void *payload = mnl_attr_get_payload(attr[NFQA_PAYLOAD]); */
>  
> -	skbinfo = attr[NFQA_SKB_INFO] ? ntohl(mnl_attr_get_u32(attr[NFQA_SKB_INFO])) : 0;
> +	if (attr[NFQA_TIMESTAMP])
> +		nfq_nlmsg_get_timestamp(attr[NFQA_TIMESTAMP], &tv);

I think we can update nfq_get_timestamp to use libmnl without breaking
backward compatibility. Same thing with all other getter functions
that we have.

Regards.

Re: [PATCH lnf-queue] api: add nfq_nlmsg_get_timestamp helper

[Florian Westphal]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> Hi Florian,
> 
> On Thu, Aug 22, 2013 at 05:07:17PM +0200, Florian Westphal wrote:
> > The NFQA_TIMESTAMP structure is in network byte order, so it seems
> > appropriate to add a helper to convert it to a timeval struct.
[..]

> I think we can update nfq_get_timestamp to use libmnl without breaking
> backward compatibility. Same thing with all other getter functions
> that we have.

How did you plan to do this without breaking api/abi?

To call the existing libnfnetlink based function given an libmnl attr[] array
you need to:

struct nfq_data d;
d.data = (void **) &attr[1];
nfq_get_timestamp(&d, &tv);

Which is just "ewww".