[PATCH v2 10/20] udp: Convert to iov_tail

[Laurent Vivier <lvivier@redhat.com>]

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

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 iov.c |  1 -
 udp.c | 34 +++++++++++++++++++++++-----------
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/iov.c b/iov.c
index 9e3786e6efe8..d09e51190d54 100644
--- a/iov.c
+++ b/iov.c
@@ -175,7 +175,6 @@ size_t iov_size(const struct iovec *iov, size_t iov_cnt)
  *		 iov array, a negative value if there is no enough room in the
  *		 destination iov array
  */
-/* cppcheck-suppress unusedFunction */
 int iov_slice(struct iovec *dst_iov, size_t dst_iov_cnt,
 	      const struct iovec *iov, size_t iov_cnt,
 	      size_t offset, size_t *bytes)
diff --git a/udp.c b/udp.c
index ab3e9d20fd74..75526f743994 100644
--- a/udp.c
+++ b/udp.c
@@ -862,15 +862,20 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
 	struct iovec m[UIO_MAXIOV];
 	const struct udphdr *uh;
 	struct udp_flow *uflow;
-	int i, s, count = 0;
+	int i, j, s, count = 0;
+	struct iov_tail data;
 	flow_sidx_t tosidx;
 	in_port_t src, dst;
+	struct udphdr uhc;
 	uint8_t topif;
 	socklen_t sl;
 
 	ASSERT(!c->no_udp);
 
-	uh = packet_get(p, idx, 0, sizeof(*uh), NULL);
+	if (!packet_base(p, idx, &data))
+		return 1;
+
+	uh = IOV_PEEK_HEADER(&data, uhc);
 	if (!uh)
 		return 1;
 
@@ -907,23 +912,30 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
 
 	pif_sockaddr(c, &to_sa, &sl, topif, &toside->eaddr, toside->eport);
 
-	for (i = 0; i < (int)p->count - idx; i++) {
-		struct udphdr *uh_send;
-		size_t len;
+	for (i = 0, j = 0; i < (int)p->count - idx && j < UIO_MAXIOV; i++) {
+		const struct udphdr *uh_send;
 
-		uh_send = packet_get(p, idx + i, 0, sizeof(*uh), &len);
+		if (!packet_base(p, idx + i, &data))
+			return p->count - idx;
+
+		uh_send = IOV_REMOVE_HEADER(&data, uhc);
 		if (!uh_send)
 			return p->count - idx;
 
 		mm[i].msg_hdr.msg_name = &to_sa;
 		mm[i].msg_hdr.msg_namelen = sl;
 
-		if (len) {
-			m[i].iov_base = (char *)(uh_send + 1);
-			m[i].iov_len = len;
+		if (data.cnt) {
+			int len;
+
+			len = iov_slice(&m[j], UIO_MAXIOV - j,
+				        &data.iov[0], data.cnt, data.off, NULL);
+			if (len < 0)
+				return p->count - idx;
 
-			mm[i].msg_hdr.msg_iov = m + i;
-			mm[i].msg_hdr.msg_iovlen = 1;
+			mm[i].msg_hdr.msg_iov = &m[j];
+			mm[i].msg_hdr.msg_iovlen = len;
+			j += len;
 		} else {
 			mm[i].msg_hdr.msg_iov = NULL;
 			mm[i].msg_hdr.msg_iovlen = 0;
-- 
@@ -862,15 +862,20 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
 	struct iovec m[UIO_MAXIOV];
 	const struct udphdr *uh;
 	struct udp_flow *uflow;
-	int i, s, count = 0;
+	int i, j, s, count = 0;
+	struct iov_tail data;
 	flow_sidx_t tosidx;
 	in_port_t src, dst;
+	struct udphdr uhc;
 	uint8_t topif;
 	socklen_t sl;
 
 	ASSERT(!c->no_udp);
 
-	uh = packet_get(p, idx, 0, sizeof(*uh), NULL);
+	if (!packet_base(p, idx, &data))
+		return 1;
+
+	uh = IOV_PEEK_HEADER(&data, uhc);
 	if (!uh)
 		return 1;
 
@@ -907,23 +912,30 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
 
 	pif_sockaddr(c, &to_sa, &sl, topif, &toside->eaddr, toside->eport);
 
-	for (i = 0; i < (int)p->count - idx; i++) {
-		struct udphdr *uh_send;
-		size_t len;
+	for (i = 0, j = 0; i < (int)p->count - idx && j < UIO_MAXIOV; i++) {
+		const struct udphdr *uh_send;
 
-		uh_send = packet_get(p, idx + i, 0, sizeof(*uh), &len);
+		if (!packet_base(p, idx + i, &data))
+			return p->count - idx;
+
+		uh_send = IOV_REMOVE_HEADER(&data, uhc);
 		if (!uh_send)
 			return p->count - idx;
 
 		mm[i].msg_hdr.msg_name = &to_sa;
 		mm[i].msg_hdr.msg_namelen = sl;
 
-		if (len) {
-			m[i].iov_base = (char *)(uh_send + 1);
-			m[i].iov_len = len;
+		if (data.cnt) {
+			int len;
+
+			len = iov_slice(&m[j], UIO_MAXIOV - j,
+				        &data.iov[0], data.cnt, data.off, NULL);
+			if (len < 0)
+				return p->count - idx;
 
-			mm[i].msg_hdr.msg_iov = m + i;
-			mm[i].msg_hdr.msg_iovlen = 1;
+			mm[i].msg_hdr.msg_iov = &m[j];
+			mm[i].msg_hdr.msg_iovlen = len;
+			j += len;
 		} else {
 			mm[i].msg_hdr.msg_iov = NULL;
 			mm[i].msg_hdr.msg_iovlen = 0;
-- 
2.49.0