netdev - [patch iproute2 v3 1/4] lib/libnetlink: Add a function rtnl_talk

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Date:   Mon, 25 Dec 2017 17:46:55 +0900
From:   Chris Mi <chrism@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     gerlitz.or@...il.com, stephen@...workplumber.org, dsahern@...il.com
Subject: [patch iproute2 v3 1/4] lib/libnetlink: Add a function rtnl_talk_msg

rtnl_talk can only send a single message to kernel. Add a new function
rtnl_talk_msg that can send multiple messages to kernel.

Signed-off-by: Chris Mi <chrism@...lanox.com>
---
 include/libnetlink.h |  3 ++
 lib/libnetlink.c     | 92 ++++++++++++++++++++++++++++++++++++++++------------
 2 files changed, 74 insertions(+), 21 deletions(-)

diff --git a/include/libnetlink.h b/include/libnetlink.h
index a4d83b9e..e95fad75 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -96,6 +96,9 @@ int rtnl_dump_filter_nc(struct rtnl_handle *rth,
 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 	      struct nlmsghdr **answer)
 	__attribute__((warn_unused_result));
+int rtnl_talk_msg(struct rtnl_handle *rtnl, struct msghdr *m,
+	      struct nlmsghdr **answer)
+	__attribute__((warn_unused_result));
 int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 	      struct nlmsghdr **answer, nl_ext_ack_fn_t errfn)
 	__attribute__((warn_unused_result));
diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index 00e6ce0c..f5f675cf 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -581,36 +581,21 @@ static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err,
 		strerror(-err->error));
 }
 
-static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
-		       struct nlmsghdr **answer,
-		       bool show_rtnl_err, nl_ext_ack_fn_t errfn)
+static int __rtnl_check_ack(struct rtnl_handle *rtnl, struct nlmsghdr **answer,
+		       bool show_rtnl_err, nl_ext_ack_fn_t errfn,
+		       unsigned int seq)
 {
 	int status;
-	unsigned int seq;
-	struct nlmsghdr *h;
+	char *buf;
 	struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
-	struct iovec iov = {
-		.iov_base = n,
-		.iov_len = n->nlmsg_len
-	};
+	struct nlmsghdr *h;
+	struct iovec iov;
 	struct msghdr msg = {
 		.msg_name = &nladdr,
 		.msg_namelen = sizeof(nladdr),
 		.msg_iov = &iov,
 		.msg_iovlen = 1,
 	};
-	char *buf;
-
-	n->nlmsg_seq = seq = ++rtnl->seq;
-
-	if (answer == NULL)
-		n->nlmsg_flags |= NLM_F_ACK;
-
-	status = sendmsg(rtnl->fd, &msg, 0);
-	if (status < 0) {
-		perror("Cannot talk to rtnetlink");
-		return -1;
-	}
 
 	while (1) {
 		status = rtnl_recvmsg(rtnl->fd, &msg, &buf);
@@ -698,12 +683,77 @@ static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 	}
 }
 
+static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
+		       struct nlmsghdr **answer,
+		       bool show_rtnl_err, nl_ext_ack_fn_t errfn)
+{
+	unsigned int seq;
+	int status;
+	struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
+	struct iovec iov = {
+		.iov_base = n,
+		.iov_len = n->nlmsg_len
+	};
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+
+	n->nlmsg_seq = seq = ++rtnl->seq;
+
+	if (answer == NULL)
+		n->nlmsg_flags |= NLM_F_ACK;
+
+	status = sendmsg(rtnl->fd, &msg, 0);
+	if (status < 0) {
+		perror("Cannot talk to rtnetlink");
+		return -1;
+	}
+
+	return __rtnl_check_ack(rtnl, answer, show_rtnl_err, errfn, seq);
+}
+
+static int __rtnl_talk_msg(struct rtnl_handle *rtnl, struct msghdr *m,
+		       struct nlmsghdr **answer,
+		       bool show_rtnl_err, nl_ext_ack_fn_t errfn)
+{
+	int iovlen = m->msg_iovlen;
+	unsigned int seq = 0;
+	struct nlmsghdr *n;
+	struct iovec *v;
+	int i, status;
+
+	for (i = 0; i < iovlen; i++) {
+		v = &m->msg_iov[i];
+		n = v->iov_base;
+		n->nlmsg_seq = seq = ++rtnl->seq;
+		if (answer == NULL)
+			n->nlmsg_flags |= NLM_F_ACK;
+	}
+
+	status = sendmsg(rtnl->fd, m, 0);
+	if (status < 0) {
+		perror("Cannot talk to rtnetlink");
+		return -1;
+	}
+
+	return __rtnl_check_ack(rtnl, answer, show_rtnl_err, errfn, seq);
+}
+
 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 	      struct nlmsghdr **answer)
 {
 	return __rtnl_talk(rtnl, n, answer, true, NULL);
 }
 
+int rtnl_talk_msg(struct rtnl_handle *rtnl, struct msghdr *m,
+	      struct nlmsghdr **answer)
+{
+	return __rtnl_talk_msg(rtnl, m, answer, true, NULL);
+}
+
 int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 		     struct nlmsghdr **answer,
 		     nl_ext_ack_fn_t errfn)
-- 
2.14.3