From: Felix Fietkau <nbd@openwrt.org>
Date: Tue, 3 Jun 2014 20:55:37 +0000 (+0200)
Subject: dns: use compile time initialization for structs, remove unnecessary call to inet_aton
X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fmdnsd.git;a=commitdiff_plain;h=00129b08c5e5df7639119cac812c765736a4c7c1;ds=inline

dns: use compile time initialization for structs, remove unnecessary call to inet_aton

Also avoids excessive stack utilization for buffer

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---

diff --git a/dns.c b/dns.c
index ecfaa63..75e739d 100644
--- a/dns.c
+++ b/dns.c
@@ -30,6 +30,7 @@
 
 #include <libubox/uloop.h>
 #include <libubox/usock.h>
+#include <libubox/utils.h>
 
 #include "announce.h"
 #include "util.h"
@@ -67,58 +68,62 @@ dns_type_string(uint16_t type)
 void
 dns_send_question(struct uloop_fd *u, char *question, int type)
 {
-	size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
-	unsigned char buffer[MAX_NAME_LEN];
-	struct dns_header h = { 0 };
-	struct dns_question q = { 0 };
-	struct msghdr m = { 0 };
-	struct iovec iov[3] = { {0}, {0}, {0} };
-	struct sockaddr_in a = { 0 };
+	static size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
+	static unsigned char buffer[MAX_NAME_LEN];
+	static struct dns_header h = {
+		.questions = cpu_to_be16(1),
+	};
+	static struct dns_question q = {
+		.class = cpu_to_be16(1),
+	};
+	static struct iovec iov[] = {
+		{
+			.iov_base = &h,
+			.iov_len = sizeof(h),
+		},
+		{
+			.iov_base = buffer,
+		},
+		{
+			.iov_base = &q,
+			.iov_len = sizeof(q),
+		}
+	};
+	static struct sockaddr_in a = {
+		.sin_family = AF_INET,
+		.sin_port = htons(MCAST_PORT),
+	};
+	static struct msghdr m = {
+		.msg_name = (struct sockaddr *) &a,
+		.msg_namelen = sizeof(a),
+		.msg_iov = iov,
+		.msg_iovlen = ARRAY_SIZE(iov),
+		.msg_control = cmsg_data,
+		.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)),
+	};
 	struct in_pktinfo *pkti;
 	struct cmsghdr *cmsg;
-	struct in_addr in;
 	int len;
 
-	a.sin_family = AF_INET;
 	a.sin_addr.s_addr = inet_addr(MCAST_ADDR);
-	a.sin_port = htons(MCAST_PORT);
-
-	h.questions = __cpu_to_be16(1);
 	q.type = __cpu_to_be16(type);
-	q.class = __cpu_to_be16(1);
 
 	len = dn_comp(question, buffer, MAX_NAME_LEN, NULL, NULL);
 	if (len < 1)
 		return;
 
-	m.msg_name = &a;
-	m.msg_namelen = sizeof(struct sockaddr_in);
-	m.msg_iov = iov;
-	m.msg_iovlen = 3;
+	iov[1].iov_len = len;
 
 	memset(cmsg_data, 0, sizeof(cmsg_data));
-	m.msg_control = cmsg_data;
-	m.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
 
 	cmsg = CMSG_FIRSTHDR(&m);
 	cmsg->cmsg_len = m.msg_controllen;
 	cmsg->cmsg_level = IPPROTO_IP;
 	cmsg->cmsg_type = IP_PKTINFO;
 
-	inet_aton(iface_ip, &in);
-
 	pkti = (struct in_pktinfo*) CMSG_DATA(cmsg);
 	pkti->ipi_ifindex = iface_index;
 
-	iov[0].iov_base = &h;
-	iov[0].iov_len = sizeof(struct dns_header);
-
-	iov[1].iov_base = buffer;
-	iov[1].iov_len = len;
-
-	iov[2].iov_base = &q;
-	iov[2].iov_len = sizeof(struct dns_question);
-
 	if (sendmsg(u->fd, &m, 0) < 0)
 		fprintf(stderr, "failed to send question\n");
 	else