1 files changed, 114 insertions, 0 deletions
diff --git a/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go b/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go
new file mode 100644
index 0000000..40ebeda
--- /dev/null
+++ b/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go
@@ -0,0 +1,114 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || linux || netbsd
+// +build aix linux netbsd
+
+package socket
+
+import (
+	"net"
+	"sync"
+)
+
+type mmsghdrs []mmsghdr
+
+func (hs mmsghdrs) unpack(ms []Message, parseFn func([]byte, string) (net.Addr, error), hint string) error {
+	for i := range hs {
+		ms[i].N = int(hs[i].Len)
+		ms[i].NN = hs[i].Hdr.controllen()
+		ms[i].Flags = hs[i].Hdr.flags()
+		if parseFn != nil {
+			var err error
+			ms[i].Addr, err = parseFn(hs[i].Hdr.name(), hint)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// mmsghdrsPacker packs Message-slices into mmsghdrs (re-)using pre-allocated buffers.
+type mmsghdrsPacker struct {
+	// hs are the pre-allocated mmsghdrs.
+	hs mmsghdrs
+	// sockaddrs is the pre-allocated buffer for the Hdr.Name buffers.
+	// We use one large buffer for all messages and slice it up.
+	sockaddrs []byte
+	// vs are the pre-allocated iovecs.
+	// We allocate one large buffer for all messages and slice it up. This allows to reuse the buffer
+	// if the number of buffers per message is distributed differently between calls.
+	vs []iovec
+}
+
+func (p *mmsghdrsPacker) prepare(ms []Message) {
+	n := len(ms)
+	if n <= cap(p.hs) {
+		p.hs = p.hs[:n]
+	} else {
+		p.hs = make(mmsghdrs, n)
+	}
+	if n*sizeofSockaddrInet6 <= cap(p.sockaddrs) {
+		p.sockaddrs = p.sockaddrs[:n*sizeofSockaddrInet6]
+	} else {
+		p.sockaddrs = make([]byte, n*sizeofSockaddrInet6)
+	}
+
+	nb := 0
+	for _, m := range ms {
+		nb += len(m.Buffers)
+	}
+	if nb <= cap(p.vs) {
+		p.vs = p.vs[:nb]
+	} else {
+		p.vs = make([]iovec, nb)
+	}
+}
+
+func (p *mmsghdrsPacker) pack(ms []Message, parseFn func([]byte, string) (net.Addr, error), marshalFn func(net.Addr, []byte) int) mmsghdrs {
+	p.prepare(ms)
+	hs := p.hs
+	vsRest := p.vs
+	saRest := p.sockaddrs
+	for i := range hs {
+		nvs := len(ms[i].Buffers)
+		vs := vsRest[:nvs]
+		vsRest = vsRest[nvs:]
+
+		var sa []byte
+		if parseFn != nil {
+			sa = saRest[:sizeofSockaddrInet6]
+			saRest = saRest[sizeofSockaddrInet6:]
+		} else if marshalFn != nil {
+			n := marshalFn(ms[i].Addr, saRest)
+			if n > 0 {
+				sa = saRest[:n]
+				saRest = saRest[n:]
+			}
+		}
+		hs[i].Hdr.pack(vs, ms[i].Buffers, ms[i].OOB, sa)
+	}
+	return hs
+}
+
+var defaultMmsghdrsPool = mmsghdrsPool{
+	p: sync.Pool{
+		New: func() interface{} {
+			return new(mmsghdrsPacker)
+		},
+	},
+}
+
+type mmsghdrsPool struct {
+	p sync.Pool
+}
+
+func (p *mmsghdrsPool) Get() *mmsghdrsPacker {
+	return p.p.Get().(*mmsghdrsPacker)
+}
+
+func (p *mmsghdrsPool) Put(packer *mmsghdrsPacker) {
+	p.p.Put(packer)
+}