From: Wouter Wijngaards <wouter@nlnetlabs.nl>
Date: Fri, 4 May 2007 13:01:20 +0000 (+0000)
Subject: Send tcp buffers using writev.
X-Git-Tag: release-0.3~19
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d4d4ba78e02a2671d3b4c7df99ffe1987db11ccd;p=thirdparty%2Funbound.git

Send tcp buffers using writev.


git-svn-id: file:///svn/unbound/trunk@284 be551aaa-1e26-0410-a405-d3ace91eadb9
---

diff --git a/doc/Changelog b/doc/Changelog
index 5aec95598..a5f2e4dc3 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -6,6 +6,8 @@
 	- alloc cache special_release() locks if necessary.
 	- rrset trustworthiness type added.
 	- thread keeps a scratchpad region for handling messages.
+	- writev used in netevent to write tcp length and data after another.
+	  This saves a roundtrip on tcp replies.
 
 3 May 2007: Wouter
 	- fill refs. Use new parse and encode to answer queries.
diff --git a/util/netevent.c b/util/netevent.c
index a65ff4ab1..c80f42f68 100644
--- a/util/netevent.c
+++ b/util/netevent.c
@@ -436,30 +436,34 @@ comm_point_tcp_handle_write(int fd, struct comm_point* c)
 
 	if(c->tcp_byte_count < sizeof(uint16_t)) {
 		uint16_t len = htons(ldns_buffer_limit(c->buffer));
-		/*
 		struct iovec iov[2];
 		iov[0].iov_base = (uint8_t*)&len + c->tcp_byte_count;
 		iov[0].iov_len = sizeof(uint16_t) - c->tcp_byte_count;
-		*/
-		r = write(fd, (uint8_t*)&len + c->tcp_byte_count, 
-			sizeof(uint16_t) - c->tcp_byte_count);
+		iov[1].iov_base = ldns_buffer_begin(c->buffer);
+		iov[1].iov_len = ldns_buffer_limit(c->buffer);
+		r = writev(fd, iov, 2);
 		if(r == -1) {
 			if(errno == EINTR || errno == EAGAIN)
 				return 1;
-			log_err("tcp write(s): %s", strerror(errno));
+			log_err("tcp writev: %s", strerror(errno));
 			return 0;
 		}
 		c->tcp_byte_count += r;
-		if(c->tcp_byte_count != sizeof(uint16_t))
+		if(c->tcp_byte_count < sizeof(uint16_t))
 			return 1;
-		ldns_buffer_set_position(c->buffer, 0);
+		ldns_buffer_set_position(c->buffer, c->tcp_byte_count - 
+			sizeof(uint16_t));
+		if(ldns_buffer_remaining(c->buffer) == 0) {
+			tcp_callback_writer(c);
+		}
+		return 1;
 	}
 	r = write(fd, ldns_buffer_current(c->buffer), 
 		ldns_buffer_remaining(c->buffer));
 	if(r == -1) {
 		if(errno == EINTR || errno == EAGAIN)
 			return 1;
-		log_err("tcp write(w): %s", strerror(errno));
+		log_err("tcp write: %s", strerror(errno));
 		return 0;
 	}
 	ldns_buffer_skip(c->buffer, r);