dhcp: Use tap_udp4_send() helper in dhcp()

The IPv4 specific dhcp() manually constructs L2 and IP headers to send its
DHCP reply packet, unlike its IPv6 equivalent in dhcpv6.c which uses the
tap_udp6_send() helper.  Now that we've broaded the parameters to
tap_udp4_send() we can use it in dhcp() to avoid some duplicated logic.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

2 files changed, 2 insertions, 17 deletions

diff --git a/dhcp.c b/dhcp.c
index 2b3af82..d22698a 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -363,22 +363,8 @@ int dhcp(const struct ctx *c, const struct pool *p)
 	if (!c->no_dhcp_dns_search)
 		opt_set_dns_search(c, sizeof(m->o));
 
-	uh->len = htons(len = offsetof(struct msg, o) + fill(m) + sizeof(*uh));
-	uh->source = htons(67);
-	uh->dest = htons(68);
-	csum_udp4(uh, c->ip4.gw, c->ip4.addr, uh + 1, len - sizeof(*uh));
-
-	iph->tot_len = htons(len += sizeof(*iph));
-	iph->daddr = c->ip4.addr;
-	iph->saddr = c->ip4.gw;
-	csum_ip4_header(iph);
-
-	len += sizeof(*eh);
-	memcpy(eh->h_dest, eh->h_source, ETH_ALEN);
-	memcpy(eh->h_source, c->mac, ETH_ALEN);
-
-	if (tap_send(c, eh, len) < 0)
-		perror("DHCP: send");
+	len = offsetof(struct msg, o) + fill(m);
+	tap_udp4_send(c, c->ip4.gw, 67, c->ip4.addr, 68, m, len);
 
 	return 1;
 }
diff --git a/tap.c b/tap.c
index d250a0b..3f78c99 100644
--- a/tap.c
+++ b/tap.c
@@ -170,7 +170,6 @@ static void *tap_push_ip4h(char *buf, in_addr_t src, in_addr_t dst,
  * @in:		UDP payload contents (not including UDP header)
  * @len:	UDP payload length (not including UDP header)
  */
-/* cppcheck-suppress unusedFunction */
 void tap_udp4_send(const struct ctx *c, in_addr_t src, in_port_t sport,
 		   in_addr_t dst, in_port_t dport,
 		   const void *in, size_t len)