[PATCH v4 09/28] icmp: Convert to iov_tail

[Laurent Vivier <lvivier@redhat.com>]

Use packet_data() and extract headers using IOV_PEEK_HEADER()
rather than packet_get().

Introduce iov_tail_msghdr() to convert iov_tail to msghdr

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 icmp.c | 25 ++++++++++++++-----------
 iov.c  | 23 +++++++++++++++++++++++
 iov.h  |  2 ++
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/icmp.c b/icmp.c
index 7e2b3423a8d1..d27d860b4af4 100644
--- a/icmp.c
+++ b/icmp.c
@@ -241,25 +241,27 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	struct icmp_ping_flow *pingf;
 	const struct flowside *tgt;
 	union sockaddr_inany sa;
-	size_t dlen, l4len;
+	struct iov_tail data;
+	struct msghdr msh;
 	uint16_t id, seq;
 	union flow *flow;
 	uint8_t proto;
 	socklen_t sl;
-	void *pkt;
 
 	(void)saddr;
 	ASSERT(pif == PIF_TAP);
 
+	if (!packet_data(p, 0, &data))
+		return -1;
+
 	if (af == AF_INET) {
 		const struct icmphdr *ih;
+		struct icmphdr ihc;
 
-		if (!(pkt = packet_get(p, 0, 0, sizeof(*ih), &dlen)))
+		ih = IOV_PEEK_HEADER(&data, ihc);
+		if (!ih)
 			return 1;
 
-		ih =  (struct icmphdr *)pkt;
-		l4len = dlen + sizeof(*ih);
-
 		if (ih->type != ICMP_ECHO)
 			return 1;
 
@@ -268,13 +270,12 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 		seq = ntohs(ih->un.echo.sequence);
 	} else if (af == AF_INET6) {
 		const struct icmp6hdr *ih;
+		struct icmp6hdr ihc;
 
-		if (!(pkt = packet_get(p, 0, 0, sizeof(*ih), &dlen)))
+		ih = IOV_PEEK_HEADER(&data, ihc);
+		if (!ih)
 			return 1;
 
-		ih = (struct icmp6hdr *)pkt;
-		l4len = dlen + sizeof(*ih);
-
 		if (ih->icmp6_type != ICMPV6_ECHO_REQUEST)
 			return 1;
 
@@ -298,8 +299,10 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	ASSERT(flow_proto[pingf->f.type] == proto);
 	pingf->ts = now->tv_sec;
 
+
 	pif_sockaddr(c, &sa, &sl, PIF_HOST, &tgt->eaddr, 0);
-	if (sendto(pingf->sock, pkt, l4len, MSG_NOSIGNAL, &sa.sa, sl) < 0) {
+	iov_tail_msghdr(&msh, &data, &sa, sl);
+	if (sendmsg(pingf->sock, &msh, MSG_NOSIGNAL) < 0) {
 		flow_dbg_perror(pingf, "failed to relay request to socket");
 	} else {
 		flow_dbg(pingf,
diff --git a/iov.c b/iov.c
index c78ec2c8e4ac..147177ab7c0d 100644
--- a/iov.c
+++ b/iov.c
@@ -210,6 +210,29 @@ int iov_slice(struct iovec *dst_iov, size_t dst_iov_cnt,
 	return j;
 }
 
+/**
+ * iov_tail_msghdr - Initialize a msghdr from an IOV tail structure
+ * @msh:		msghdr to initialize
+ * @tail:		iov_tail to use to set msg_iov and msg_iovlen
+ * @msg_name:		Pointer to set to msg_name
+ * @msg_namelen:	Size of @msg_name
+ */
+void iov_tail_msghdr(struct msghdr *msh, struct iov_tail *tail,
+		     void *msg_name, socklen_t msg_namelen)
+{
+	iov_tail_prune(tail);
+
+	ASSERT(tail->off == 0);
+
+	msh->msg_name = msg_name;
+	msh->msg_namelen = msg_namelen;
+	msh->msg_iov = (struct iovec *)tail->iov;
+	msh->msg_iovlen = tail->cnt;
+	msh->msg_control = NULL;
+	msh->msg_controllen = 0;
+	msh->msg_flags = 0;
+}
+
 /**
  * iov_tail_prune() - Remove any unneeded buffers from an IOV tail
  * @tail:	IO vector tail (modified)
diff --git a/iov.h b/iov.h
index 8e8c7efe6639..8b73f99b063e 100644
--- a/iov.h
+++ b/iov.h
@@ -83,6 +83,8 @@ struct iov_tail {
 #define IOV_TAIL_FROM_BUF(buf_, len_, off_) \
 	IOV_TAIL((&(const struct iovec){ .iov_base = (buf_), .iov_len = (len_) }), 1, (off_))
 
+void iov_tail_msghdr(struct msghdr *msh, struct iov_tail *tail,
+		     void *msg_name, socklen_t msg_namelen);
 bool iov_tail_prune(struct iov_tail *tail);
 size_t iov_tail_size(struct iov_tail *tail);
 bool iov_tail_drop(struct iov_tail *tail, size_t len);
-- 
@@ -83,6 +83,8 @@ struct iov_tail {
 #define IOV_TAIL_FROM_BUF(buf_, len_, off_) \
 	IOV_TAIL((&(const struct iovec){ .iov_base = (buf_), .iov_len = (len_) }), 1, (off_))
 
+void iov_tail_msghdr(struct msghdr *msh, struct iov_tail *tail,
+		     void *msg_name, socklen_t msg_namelen);
 bool iov_tail_prune(struct iov_tail *tail);
 size_t iov_tail_size(struct iov_tail *tail);
 bool iov_tail_drop(struct iov_tail *tail, size_t len);
-- 
2.49.0