From fa4c10f4d7a7b9e4b3217289d13cfe78061649dd Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@gnumonks.org>
Date: Tue, 21 Jan 2014 17:32:32 +0100
Subject: [PATCH] genl: introduce genl_nlmsg_build_hdr and use it

Add new generic function to build the netlink and genetlink headers.
---
 genl.c           | 19 +++++++++++++++++++
 genl.h           |  3 +++
 gtp-tunnel-add.c | 13 +++----------
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/genl.c b/genl.c
index b2edec3..a682e1f 100644
--- a/genl.c
+++ b/genl.c
@@ -6,6 +6,25 @@
 #include <libmnl/libmnl.h>
 #include <linux/genetlink.h>
 
+struct nlmsghdr *
+genl_nlmsg_build_hdr(char *buf, uint16_t type, uint16_t flags, uint32_t seq,
+		     uint8_t cmd)
+{
+	struct nlmsghdr *nlh;
+	struct genlmsghdr *genl;
+
+	nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type = type;
+	nlh->nlmsg_flags = NLM_F_REQUEST | flags;
+	nlh->nlmsg_seq = seq;
+
+	genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
+	genl->cmd = cmd;
+	genl->version = 0;
+
+	return nlh;
+}
+
 static int genl_ctrl_validate_cb(const struct nlattr *attr, void *data)
 {
 	const struct nlattr **tb = data;
diff --git a/genl.h b/genl.h
index ccecfde..684c8d0 100644
--- a/genl.h
+++ b/genl.h
@@ -3,6 +3,9 @@
 
 #include <libmnl/libmnl.h>
 
+struct nlmsghdr *genl_nlmsg_build_hdr(char *buf, uint16_t type, uint16_t flags,
+				      uint32_t seq, uint8_t cmd);
+
 struct mnl_socket *genl_socket_open(void);
 int genl_socket_talk(struct mnl_socket *nl, struct nlmsghdr *nlh,
 		     int (*cb)(const struct nlmsghdr *nlh, void *data),
diff --git a/gtp-tunnel-add.c b/gtp-tunnel-add.c
index 2e34319..08679c2 100644
--- a/gtp-tunnel-add.c
+++ b/gtp-tunnel-add.c
@@ -11,19 +11,12 @@
 
 static uint32_t seq;
 
-static struct nlmsghdr *build_msg(int genl_type, char *buf, int i, uint32_t ifidx)
+static struct nlmsghdr *build_msg(int type, char *buf, int i, uint32_t ifidx)
 {
 	struct nlmsghdr *nlh;
-	struct genlmsghdr *genl;
 
-	nlh = mnl_nlmsg_put_header(buf);
-	nlh->nlmsg_type	= genl_type;
-	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
-	nlh->nlmsg_seq = ++seq;
-
-	genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
-	genl->cmd = GTP_CMD_TUNNEL_NEW;
-	genl->version = 0;
+	nlh = genl_nlmsg_build_hdr(buf, type, NLM_F_ACK, ++seq,
+				   GTP_CMD_TUNNEL_NEW);
 
 	mnl_attr_put_u32(nlh, GTPA_VERSION, GTP_V0);
 	mnl_attr_put_u32(nlh, GTPA_LINK, ifidx);