[PATCH 15/18] dhcp: 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>
---
 dhcp.c | 38 ++++++++++++++++++++++----------------
 iov.c  |  1 -
 2 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/dhcp.c b/dhcp.c
index b0de04be6f27..f3167beb18b7 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -302,27 +302,32 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len)
  */
 int dhcp(const struct ctx *c, const struct pool *p)
 {
-	size_t mlen, dlen, offset = 0, opt_len, opt_off = 0;
+	size_t mlen, dlen, opt_len, opt_off = 0;
 	char macstr[ETH_ADDRSTRLEN];
 	struct in_addr mask, dst;
 	const struct ethhdr *eh;
 	const struct iphdr *iph;
 	const struct udphdr *uh;
+	struct iov_tail data;
 	struct msg const *m;
+	struct msg mc;
+	struct ethhdr ehc;
+	struct iphdr iphc;
+	struct udphdr uhc;
 	struct msg reply;
 	unsigned int i;
 
-	eh  = packet_get(p, 0, offset, sizeof(*eh),  NULL);
-	offset += sizeof(*eh);
+	if (!packet_base(p, 0, &data))
+		return -1;
 
-	iph = packet_get(p, 0, offset, sizeof(*iph), NULL);
+	eh = IOV_REMOVE_HEADER(&data, ehc);
+	iph = IOV_PEEK_HEADER(&data, iphc);
 	if (!eh || !iph)
 		return -1;
 
-	offset += iph->ihl * 4UL;
-	uh  = packet_get(p, 0, offset, sizeof(*uh),  &mlen);
-	offset += sizeof(*uh);
+	data.off += iph->ihl * 4UL;
 
+	uh = IOV_REMOVE_HEADER(&data, uhc);
 	if (!uh)
 		return -1;
 
@@ -332,7 +337,9 @@ int dhcp(const struct ctx *c, const struct pool *p)
 	if (c->no_dhcp)
 		return 1;
 
-	m   = packet_get(p, 0, offset, offsetof(struct msg, o), &opt_len);
+	mlen = iov_tail_size(&data);
+	m = (struct msg const *)iov_remove_header_(&data, &mc, offsetof(struct msg, o),
+						   __alignof__(struct msg));
 	if (!m						||
 	    mlen  != ntohs(uh->len) - sizeof(*uh)	||
 	    mlen  <  offsetof(struct msg, o)		||
@@ -355,25 +362,24 @@ int dhcp(const struct ctx *c, const struct pool *p)
 	memset(&reply.file,	0,		sizeof(reply.file));
 	reply.magic		= m->magic;
 
-	offset += offsetof(struct msg, o);
-
 	for (i = 0; i < ARRAY_SIZE(opts); i++)
 		opts[i].clen = -1;
 
+	opt_len = iov_tail_size(&data);
 	while (opt_off + 2 < opt_len) {
-		const uint8_t *olen, *val;
+		const uint8_t *olen;
 		uint8_t *type;
 
-		type = packet_get(p, 0, offset + opt_off,	1,	NULL);
-		olen = packet_get(p, 0, offset + opt_off + 1,	1,	NULL);
+		type = iov_tail_ptr(&data, opt_off, 1);
+		olen = iov_tail_ptr(&data, opt_off + 1, 1);
 		if (!type || !olen)
 			return -1;
 
-		val =  packet_get(p, 0, offset + opt_off + 2,	*olen,	NULL);
-		if (!val)
+		if (iov_tail_size(&data) < opt_off + 2 + *olen)
 			return -1;
 
-		memcpy(&opts[*type].c, val, *olen);
+		iov_to_buf(&data.iov[0], data.cnt, data.off + opt_off + 2,
+			   &opts[*type].c, *olen);
 		opts[*type].clen = *olen;
 		opt_off += *olen + 2;
 	}
diff --git a/iov.c b/iov.c
index 0c69379316aa..66f15585a61a 100644
--- a/iov.c
+++ b/iov.c
@@ -253,7 +253,6 @@ bool iov_drop(struct iov_tail *tail, size_t len)
  * Returns:	pointer to the data in the tail, NULL if the
  *		tail doesn't contains @len bytes.
  */
-/* cppcheck-suppress unusedFunction */
 void *iov_tail_ptr(struct iov_tail *tail, size_t off, size_t len)
 {
 	const struct iovec *iov;
-- 
@@ -253,7 +253,6 @@ bool iov_drop(struct iov_tail *tail, size_t len)
  * Returns:	pointer to the data in the tail, NULL if the
  *		tail doesn't contains @len bytes.
  */
-/* cppcheck-suppress unusedFunction */
 void *iov_tail_ptr(struct iov_tail *tail, size_t off, size_t len)
 {
 	const struct iovec *iov;
-- 
2.49.0