libnetfilter_queue nfattr[] abstraction

Hi,

This patch is a proposal to suppress the use of struct nfattr* nfa[] like params in user level function.

This just hide the low-level structure behind a dummy structure. But from a user point of view, this structure should remain inchanged even if the kernel internal are changing.

I've checked the provided test util and NuFW against the modified library.

BR,

Eric Leblond <[email protected]>

==== Patch <netfilter_queue_datas> level 1
Source: [No source]
Target: f6f8485a-58f1-0310-9e83-9cad51fe5e11:/netfilter/libnetfilter_queue:1217 Log:
introduce nfqnl_q_datas struct to hide struct nfattr * nfa[]
=== include/libnetfilter_queue/libnetfilter_queue.h
==================================================================

@@ -18,6 +18,10 @@
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nfnetlink_queue.h>
 
+struct nfqnl_q_datas {
+	struct nfattr ** data;
+};
+
 struct nfqnl_handle;
 struct nfqnl_q_handle;
 

@@ -27,7 +31,7 @@
 extern int nfqnl_fd(struct nfqnl_handle *h);
 
 typedef int  nfqnl_callback(struct nfqnl_q_handle *gh, struct nfgenmsg *nfmsg,
-		       struct nfattr *nfa[], void *data);
+		       struct nfqnl_q_datas* nfa, void *data);
 
 
 extern struct nfqnl_handle *nfqnl_open(void);

@@ -63,23 +67,23 @@
 /* message parsing function */
 
 extern struct nfqnl_msg_packet_hdr *
-				nfqnl_get_msg_packet_hdr(struct nfattr *nfa[]);
+				nfqnl_get_msg_packet_hdr(struct nfqnl_q_datas* nfa);
 
-extern u_int32_t nfqnl_get_nfmark(struct nfattr *nfa[]);
+extern u_int32_t nfqnl_get_nfmark(struct nfqnl_q_datas* nfa);
 
 extern struct nfqnl_msg_packet_timestamp *
-				nfqnl_get_timestamp(struct nfattr *nfa[]);
+				nfqnl_get_timestamp(struct nfqnl_q_datas* nfa);
 
 /* return 0 if not set */
-extern u_int32_t nfqnl_get_indev(struct nfattr *nfa[]);
-extern u_int32_t nfqnl_get_physindev(struct nfattr *nfa[]);
-extern u_int32_t nfqnl_get_outdev(struct nfattr *nfa[]);
-extern u_int32_t nfqnl_get_physoutdev(struct nfattr *nfa[]);
+extern u_int32_t nfqnl_get_indev(struct nfqnl_q_datas* nfa);
+extern u_int32_t nfqnl_get_physindev(struct nfqnl_q_datas* nfa);
+extern u_int32_t nfqnl_get_outdev(struct nfqnl_q_datas* nfa);
+extern u_int32_t nfqnl_get_physoutdev(struct nfqnl_q_datas* nfa);
 
-extern struct nfqnl_msg_packet_hw *nfqnl_get_packet_hw(struct nfattr *nfa[]);
+extern struct nfqnl_msg_packet_hw *nfqnl_get_packet_hw(struct nfqnl_q_datas* nfa);
 
 /* return 0 if problem */
-extern int nfqnl_get_payload(struct nfattr *nfa[],
+extern int nfqnl_get_payload(struct nfqnl_q_datas* nfa,
 			     char ** data, unsigned int* datalen);
 
 

=== src/libnetfilter_queue.c
==================================================================

==== BEGIN SVK PATCH BLOCK ====
Version: svk 1.04 (linux)

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==== END SVK PATCH BLOCK ====

looks fine to me. I'll rename nfnl_q_datas into nfnl_q_data, though.

ACK. this can easily be enforced if we put the structure definition into the C file, and just have a dummy 'struct nfnl_q_data' declaration in the header.

Please re-check after my changes went in (maybe in 30mins).

- Harald Welte <[email protected]>                 http://netfilter.org/
============================================================================
  "Fragmentation is like classful addressing -- an interesting early
   architectural error that shows how much experimentation was going
   on while IP was being designed."                    -- Paul Vixie

Done. I've found a problem with timestamp related function. timestamp structure can not be renamed as it is defined in kernel.
I attach a patch that correct this.

For timestamp, we could use the glibc "struct timeval" but the user will have to free the structure after use as it is not a pointer to the message from kernel.

BR,

Eric Leblond <[email protected]>

=== include/libnetfilter_queue/libnetfilter_queue.h
==================================================================

@@ -68,7 +68,7 @@
 
 extern u_int32_t nfq_get_nfmark(struct nfq_data *nfad);
 
-extern struct nfq_msg_packet_timestamp *
+extern struct nfqnl_msg_packet_timestamp *
 				nfq_get_timestamp(struct nfq_data *nfad);
 
 /* return 0 if not set */

=== src/libnetfilter_queue.c
==================================================================

@@ -336,7 +335,7 @@
 	return ntohl(nfnl_get_data(nfad->data, NFQA_MARK, u_int32_t));
 }
 
-struct nfq_msg_packet_timestamp *nfq_get_timestamp(struct nfq_data *nfad)
+struct nfqnl_msg_packet_timestamp *nfq_get_timestamp(struct nfq_data *nfad)
 {
 	return nfnl_get_pointer_to_data(nfad->data, NFQA_TIMESTAMP,
 					struct nfq_msg_packet_timestamp);