Re: [PATCH] message parsing functions for nfqueue

[Eric Leblond <eric@inl.fr>]

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Hi,

On Fri, 2005-08-12 at 14:04 +0200, Harald Welte wrote:
> On Fri, Aug 12, 2005 at 10:42:56AM +0200, Eric Leblond wrote:
> > > Eric Leblond wrote:
> > >> This is a patch against libnfnetlink_queue.
> > >>
> > >> It adds "high" level functions to access to the data contained in a
> > >> nfqueue message. These are mostly encapsulation of NFA macros.

> I like the generic macros proposed by Pablo, but making nfnetlink_queue
> users directly use them is somewhat of a layering violation.

I've finally found some time to rewrite the provided functions with
Pablo's macros.

I've tested it against provided exemple and NuFW and it seems to work
fine.

BR,
-- 
Eric Leblond <eric@inl.fr>
INL

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Index: utils/nfqnl_test.c
===================================================================
--- utils/nfqnl_test.c	(révision 4261)
+++ utils/nfqnl_test.c	(copie de travail)
@@ -11,35 +11,37 @@
 static u_int32_t print_pkt (struct nfattr *tb[])
 {
 	int id = 0;
-
-	if (tb[NFQA_PACKET_HDR-1]) {
-		struct nfqnl_msg_packet_hdr *ph = 
-					NFA_DATA(tb[NFQA_PACKET_HDR-1]);
+	struct nfqnl_msg_packet_hdr *ph;
+	u_int32_t mark,ifi; 
+	int ret;
+	unsigned int datalength;
+	char * data;
+	
+	ph = nfqnl_get_msg_packet_hdr(tb);
+	if (ph){
 		id = ntohl(ph->packet_id);
 		printf("hw_protocol=0x%04x hook=%u id=%u ",
 			ntohs(ph->hw_protocol), ph->hook, id);
 	}
-
-	if (tb[NFQA_MARK-1]) {
-		u_int32_t mark = 
-			ntohl(*(u_int32_t *)NFA_DATA(tb[NFQA_MARK-1]));
+	
+	mark=nfqnl_get_nfmark(tb);
+	if (mark) {
 		printf("mark=%u ", mark);
 	}
 
-	if (tb[NFQA_IFINDEX_INDEV-1]) {
-		u_int32_t ifi = 
-			ntohl(*(u_int32_t *)NFA_DATA(tb[NFQA_IFINDEX_INDEV-1]));
-		printf("indev=%u ", ifi);
+	ret=nfqnl_get_indev(tb,&ifi,NULL);
+	if (ret) {
+		printf("indev=%u ", ntohl(ifi));
 	}
 
-	if (tb[NFQA_IFINDEX_OUTDEV-1]) {
-		u_int32_t ifi =
-			ntohl(*(u_int32_t *)NFA_DATA(tb[NFQA_IFINDEX_OUTDEV-1]));
-		printf("outdev=%u ", ifi);
+	ret=nfqnl_get_outdev(tb,&ifi,NULL);
+	if (ret) {
+		printf("outdev=%u ", ntohl(ifi));
 	}
 
-	if (tb[NFQA_PAYLOAD-1]) {
-		printf("payload_len=%d ", NFA_PAYLOAD(tb[NFQA_PAYLOAD-1]));
+	ret=nfqnl_get_payload(tb,&data,&datalength);
+	if (ret) {
+		printf("payload_len=%d ", datalength);
 	}
 
 	fputc('\n', stdout);
Index: include/libnfnetlink_queue/libnfnetlink_queue.h
===================================================================
--- include/libnfnetlink_queue/libnfnetlink_queue.h	(révision 4261)
+++ include/libnfnetlink_queue/libnfnetlink_queue.h	(copie de travail)
@@ -2,6 +2,10 @@
  *
  * (C) 2005 by Harald Welte <laforge@gnumonks.org>
  *
+ *
+ * Changelog : 
+ * 	(2005/08/11)  added  parsing function (Eric Leblond <regit@inl.fr>)
+ * 
  * This software may be used and distributed according to the terms
  * of the GNU General Public License, incorporated herein by reference.
  */
@@ -21,7 +25,7 @@
 extern struct nfnl_handle *nfqnl_nfnlh(struct nfqnl_handle *h);
 extern int nfqnl_fd(struct nfqnl_handle *h);
 
-typedef nfqnl_callback(struct nfqnl_q_handle *gh, struct nfgenmsg *nfmsg,
+typedef int  nfqnl_callback(struct nfqnl_q_handle *gh, struct nfgenmsg *nfmsg,
 		       struct nfattr *nfa[], void *data);
 
 
@@ -47,10 +51,33 @@
 			     u_int32_t verdict,
 			     u_int32_t data_len,
 			     unsigned char *buf);
+
 extern int nfqnl_set_verdict_mark(struct nfqnl_q_handle *qh, 
 				  u_int32_t id,
 			   	  u_int32_t verdict, 
 				  u_int32_t mark,
 			   	  u_int32_t datalen,
 				  unsigned char *buf);
+
+/* message parsing function */
+
+extern struct nfqnl_msg_packet_hdr * nfqnl_get_msg_packet_hdr(struct nfattr *nfa[]);
+
+extern u_int32_t nfqnl_get_nfmark(struct nfattr *nfa[]);
+
+extern struct nfqnl_msg_packet_timestamp * nfqnl_get_timestamp(struct nfattr *nfa[]);
+
+/* return 0 if not set */
+extern int nfqnl_get_indev(struct nfattr *nfa[],u_int32_t* indev, u_int32_t* physindev);
+
+/* return 0 if not set */
+extern int nfqnl_get_outdev(struct nfattr *nfa[],u_int32_t* outdev, u_int32_t* physoutdev);
+
+extern struct nfqnl_msg_packet_hw * nfqnl_get_packet_hw(struct nfattr *nfa[]);
+
+/* return 0 if problem */
+extern int nfqnl_get_payload(struct nfattr *nfa[],char ** data,unsigned int* datalen);
+
+
+
 #endif	/* __LIBNFQNETLINK_H */
Index: src/libnfnetlink_queue.c
===================================================================
--- src/libnfnetlink_queue.c	(révision 4261)
+++ src/libnfnetlink_queue.c	(copie de travail)
@@ -89,9 +89,9 @@
 }
 
 /* build a NFQNL_MSG_CONFIG message */
-static int
+	static int
 __build_send_cfg_msg(struct nfqnl_handle *h, u_int8_t command,
-		     u_int16_t queuenum, u_int16_t pf)
+		u_int16_t queuenum, u_int16_t pf)
 {
 	char buf[NFNL_HEADER_LEN
 		+NFA_LENGTH(sizeof(struct nfqnl_msg_config_cmd))];
@@ -99,7 +99,7 @@
 	struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
 
 	nfnl_fill_hdr(&h->nfnlh, nmh, 0, AF_UNSPEC, queuenum,
-		      NFQNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
+			NFQNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
 
 	cmd.command = command;
 	cmd.pf = htons(pf);
@@ -109,7 +109,7 @@
 }
 
 static int __nfqnl_rcv_pkt(struct nlmsghdr *nlh, struct nfattr *nfa[],
-			   void *data)
+		void *data)
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	struct nfqnl_handle *h = data;
@@ -196,9 +196,9 @@
 
 /* bind this socket to a specific queue number */
 struct nfqnl_q_handle *nfqnl_create_queue(struct nfqnl_handle *h, 
-					  u_int16_t num,
-					  nfqnl_callback *cb,
-					  void *data)
+		u_int16_t num,
+		nfqnl_callback *cb,
+		void *data)
 {
 	int ret;
 	struct nfqnl_q_handle *qh;
@@ -243,7 +243,7 @@
 }
 
 int nfqnl_set_mode(struct nfqnl_q_handle *qh,
-		   u_int8_t mode, u_int32_t range)
+		u_int8_t mode, u_int32_t range)
 {
 	char buf[NFNL_HEADER_LEN
 		+NFA_LENGTH(sizeof(struct nfqnl_msg_config_params))];
@@ -251,19 +251,19 @@
 	struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
 
 	nfnl_fill_hdr(&qh->h->nfnlh, nmh, 0, AF_UNSPEC, qh->id,
-		      NFQNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
+			NFQNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
 
 	params.copy_range = htonl(range);
 	params.copy_mode = mode;
 	nfnl_addattr_l(nmh, sizeof(buf), NFQA_CFG_PARAMS, &params,
-		       sizeof(params));
+			sizeof(params));
 
 	return nfnl_talk(&qh->h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
 }
 
 static int __set_verdict(struct nfqnl_q_handle *qh, u_int32_t id,
-			 u_int32_t verdict, u_int32_t mark, int set_mark,
-			 u_int32_t data_len, unsigned char *data)
+		u_int32_t verdict, u_int32_t mark, int set_mark,
+		u_int32_t data_len, unsigned char *data)
 {
 	struct nfqnl_msg_verdict_hdr vh;
 	char buf[NFNL_HEADER_LEN
@@ -278,8 +278,8 @@
 	vh.id = htonl(id);
 
 	nfnl_fill_hdr(&qh->h->nfnlh, nmh, 0, AF_UNSPEC, qh->id,
-		      NFQNL_MSG_VERDICT, NLM_F_REQUEST);
-			
+			NFQNL_MSG_VERDICT, NLM_F_REQUEST);
+
 	/* add verdict header */
 	nfnl_addattr_l(nmh, sizeof(buf), NFQA_VERDICT_HDR, &vh, sizeof(vh));
 
@@ -294,7 +294,7 @@
 		struct nfattr data_attr;
 
 		nfnl_build_nfa_iovec(&iov[1], &data_attr, NFQA_PAYLOAD,
-				     data_len, data);
+				data_len, data);
 		nvecs += 2;
 	}
 
@@ -302,15 +302,87 @@
 }
 
 int nfqnl_set_verdict(struct nfqnl_q_handle *qh, u_int32_t id,
-		      u_int32_t verdict, u_int32_t data_len, 
-		      unsigned char *buf)
+		u_int32_t verdict, u_int32_t data_len, 
+		unsigned char *buf)
 {
 	return __set_verdict(qh, id, verdict, 0, 0, data_len, buf);
 }	
 
 int nfqnl_set_verdict_mark(struct nfqnl_q_handle *qh, u_int32_t id,
-			   u_int32_t verdict, u_int32_t mark,
-			   u_int32_t datalen, unsigned char *buf)
+		u_int32_t verdict, u_int32_t mark,
+		u_int32_t datalen, unsigned char *buf)
 {
 	return __set_verdict(qh, id, verdict, mark, 1, datalen, buf);
 }
+
+/*************************************************************
+ * Message parsing functions 
+ *************************************************************/
+
+#define nfnl_get_data(tb, attr, type)			\
+	({	type __ret = 0;					\
+	 if (tb[attr-1])					\
+	 __ret = *(type *)NFA_DATA(tb[attr-1]);	\
+	 __ret;						\
+	 })
+
+#define nfnl_get_pointer_to_data(tb, attr, type)	\
+	({	type *__ret = NULL;				\
+	 if (tb[attr-1])					\
+	 __ret = NFA_DATA(tb[attr-1]);		\
+	 __ret;						\
+	 })
+
+struct nfqnl_msg_packet_hdr * nfqnl_get_msg_packet_hdr(struct nfattr *nfa[]){
+	return nfnl_get_pointer_to_data(nfa,NFQA_PACKET_HDR,struct nfqnl_msg_packet_hdr );
+}
+
+uint32_t nfqnl_get_nfmark(struct nfattr *nfa[]){
+	return nfnl_get_data(nfa, NFQA_MARK, u_int32_t);
+}
+
+struct nfqnl_msg_packet_timestamp * nfqnl_get_timestamp(struct nfattr *nfa[]){
+	return nfnl_get_pointer_to_data(nfa,NFQA_TIMESTAMP,struct nfqnl_msg_packet_timestamp);
+}
+
+/* return 0 if not set */
+int nfqnl_get_indev(struct nfattr *nfa[],u_int32_t* indev, u_int32_t* physindev){
+	if (indev){
+		*indev=nfnl_get_data(nfa, NFQA_IFINDEX_INDEV, u_int32_t);
+		if (physindev){
+			*physindev=nfnl_get_data(nfa, NFQA_IFINDEX_PHYSINDEV, u_int32_t);
+		}
+		return 1;
+	}
+	return 0;
+}
+
+/* return 0 if not set */
+int nfqnl_get_outdev(struct nfattr *nfa[],u_int32_t* outdev, u_int32_t* physoutdev){
+	if (outdev){
+		*outdev=nfnl_get_data(nfa, NFQA_IFINDEX_OUTDEV, u_int32_t);
+		if (physoutdev){
+			*physoutdev=nfnl_get_data(nfa, NFQA_IFINDEX_PHYSOUTDEV, u_int32_t);
+		}
+		return 1;
+	}
+	return 0;
+}
+
+struct nfqnl_msg_packet_hw * nfqnl_get_packet_hw(struct nfattr *nfa[]){
+	return nfnl_get_pointer_to_data(nfa,NFQA_HWADDR,struct nfqnl_msg_packet_hw);
+}
+
+int nfqnl_get_payload(struct nfattr *nfa[],char ** data,unsigned int* datalen){
+	if (datalen) {
+		*data=nfnl_get_pointer_to_data(nfa, NFQA_PAYLOAD, char*);
+		if (*data){
+			*datalen=NFA_PAYLOAD(nfa[NFQA_PAYLOAD-1]);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+
+
Index: src/Makefile.am
===================================================================
--- src/Makefile.am	(révision 4261)
+++ src/Makefile.am	(copie de travail)
@@ -2,7 +2,7 @@
 
 #EXTRA_DIST = $(man_MANS) acinclude.m4
 
-INCLUDES = $(all_includes) -I$(top_srcdir)/include -I${KERNELDIR} 
+INCLUDES = $(all_includes) -I$(top_srcdir)/include -I${KERNELDIR}
 AM_CFLAGS=-fPIC -Wall
 LIBS=
 

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