[PATCH libnetfilter_queue v3 10/15] src: Convert remaining nfq_* functions to use libmnl

[Duncan Roe <duncan_roe@xxxxxxxxxxxxxxx>]

Converted: nfq_set_verdict2(), nfq_set_verdict_batch2(),
           nfq_set_verdict_mark(), nfq_get_nfmark() [again] &
           nfq_get_skbinfo()
We only use 2 iovecs instead of 3
by tacking the data attribute onto the end of the first iovec buffer.

Signed-off-by: Duncan Roe <duncan_roe@xxxxxxxxxxxxxxx>
---
 Changes in v3: (none)

 Changes in v2:
 - Move nfq_set_mode() conversion to patch 5
 - Rebase to account for updated patches

 src/libnetfilter_queue.c | 67 +++++++++++++++++++++-------------------
 1 file changed, 35 insertions(+), 32 deletions(-)

diff --git a/src/libnetfilter_queue.c b/src/libnetfilter_queue.c
index 8a11f41..ecdd144 100644
--- a/src/libnetfilter_queue.c
+++ b/src/libnetfilter_queue.c
@@ -989,17 +989,9 @@ static int __set_verdict(struct nfq_q_handle *qh, uint32_t id,
 {
 	char buf[MNL_SOCKET_BUFFER_SIZE];
 	struct nlmsghdr *nlh;
+	static struct sockaddr_nl snl = {.nl_family = AF_NETLINK };
 
-	struct iovec iov[3];
-	int nvecs;
-
-	/* This must be declared here (and not inside the data
-	 * handling block) because the iovec points to this. */
-	struct nlattr data_attr;
-
-	memset(iov, 0, sizeof(iov));
-
-	nlh = nfq_nlmsg_put(buf, NFQNL_MSG_VERDICT, qh->id);
+	nlh = nfq_nlmsg_put(buf, type, qh->id);
 
 	/* add verdict header */
 	nfq_nlmsg_verdict_put(nlh, id, verdict);
@@ -1013,26 +1005,38 @@ static int __set_verdict(struct nfq_q_handle *qh, uint32_t id,
 	 */
 	if (!data_len)
 		return mnl_socket_sendto(qh->h->nl, nlh, nlh->nlmsg_len);
+	{
+		struct iovec iov[2];
+		struct nlattr *data_attr = mnl_nlmsg_get_payload_tail(nlh);
+		const struct msghdr msg = {
+			.msg_name = &snl,
+			.msg_namelen = sizeof(snl),
+			.msg_iov = iov,
+			.msg_iovlen = 2,
+			.msg_control = NULL,
+			.msg_controllen = 0,
+			.msg_flags = 0,
+		};
+
+		mnl_attr_put(nlh, NFQA_PAYLOAD, 0, NULL);
+
+		iov[0].iov_base = nlh;
+		iov[0].iov_len = nlh->nlmsg_len;
+		/* The typecast here is to cast away data's const-ness: */
+		iov[1].iov_base = (unsigned char *)data;
+		iov[1].iov_len = data_len;
 
-	iov[0].iov_base = nlh;
-	iov[0].iov_len = NLMSG_TAIL(nlh) - (void *)nlh;
-	nvecs = 1;
-
-	if (data_len) {
-		/* Temporary cast until we get rid of nfnl_build_nfa_iovec() */
-		nfnl_build_nfa_iovec(&iov[1], (struct nfattr *)&data_attr,
-		//nfnl_build_nfa_iovec(&iov[1], &data_attr,
-				     NFQA_PAYLOAD, data_len,
-				     (unsigned char *) data);
-		nvecs += 2;
 		/* Add the length of the appended data to the message
-		 * header.  The size of the attribute is given in the
-		 * nla_len field and is set in the nfnl_build_nfa_iovec()
-		 * function. */
-		nlh->nlmsg_len += data_attr.nla_len;
-	}
+		 * header and attribute length.
+		 * No padding is needed: this is the end of the message.
+		 */
+
+		nlh->nlmsg_len += data_len;
 
-	return nfnl_sendiov(qh->h->nfnlh, iov, nvecs, 0);
+		data_attr->nla_len += data_len;
+
+		return sendmsg(qh->h->nfnlh->fd, &msg, 0);
+	}
 }
 
 /**
@@ -1121,7 +1125,7 @@ EXPORT_SYMBOL
 int nfq_set_verdict_batch2(struct nfq_q_handle *qh, uint32_t id,
 			   uint32_t verdict, uint32_t mark)
 {
-	return __set_verdict(qh, id, verdict, htonl(mark), 1, 0,
+	return __set_verdict(qh, id, verdict, mark, 1, 0,
 				NULL, NFQNL_MSG_VERDICT_BATCH);
 }
 
@@ -1144,7 +1148,7 @@ int nfq_set_verdict_mark(struct nfq_q_handle *qh, uint32_t id,
 			 uint32_t verdict, uint32_t mark,
 			 uint32_t data_len, const unsigned char *buf)
 {
-	return __set_verdict(qh, id, verdict, mark, 1, data_len, buf,
+	return __set_verdict(qh, id, verdict, ntohl(mark), 1, data_len, buf,
 						NFQNL_MSG_VERDICT);
 }
 
@@ -1212,7 +1216,6 @@ uint32_t nfq_get_nfmark(struct nfq_data *nfad)
 		return 0;
 
 	return ntohl(mnl_attr_get_u32(nfad->data[NFQA_MARK]));
-	return ntohl(nfnl_get_data(nfad->data, NFQA_MARK, uint32_t));
 }
 
 /**
@@ -1476,10 +1479,10 @@ struct nfqnl_msg_packet_hw *nfq_get_packet_hw(struct nfq_data *nfad)
 EXPORT_SYMBOL
 uint32_t nfq_get_skbinfo(struct nfq_data *nfad)
 {
-	if (!nfnl_attr_present(nfad->data, NFQA_SKB_INFO))
+	if (!nfad->data[NFQA_SKB_INFO])
 		return 0;
 
-	return ntohl(nfnl_get_data(nfad->data, NFQA_SKB_INFO, uint32_t));
+	return ntohl(mnl_attr_get_u32(nfad->data[NFQA_SKB_INFO]));
 }
 
 /**
-- 
2.35.8