From 90050671b71cd4629b27809055bd562ab76c4460 Mon Sep 17 00:00:00 2001
From: Paul Holzinger <paul.holzinger@web.de>
Date: Wed, 24 Feb 2021 10:41:56 +0100
Subject: Add dns search domains from cni response to resolv.conf

This fixes slow local host name lookups.
see containers/dnsname#57

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>
---
 libpod/container_internal_linux.go | 12 +++++++++---
 test/e2e/run_networking_test.go    | 14 ++++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 9c3e91a97..dc0418148 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -1713,8 +1713,9 @@ rootless=%d
 // generateResolvConf generates a containers resolv.conf
 func (c *Container) generateResolvConf() (string, error) {
 	var (
-		nameservers    []string
-		cniNameServers []string
+		nameservers      []string
+		cniNameServers   []string
+		cniSearchDomains []string
 	)
 
 	resolvConf := "/etc/resolv.conf"
@@ -1766,6 +1767,10 @@ func (c *Container) generateResolvConf() (string, error) {
 			cniNameServers = append(cniNameServers, i.DNS.Nameservers...)
 			logrus.Debugf("adding nameserver(s) from cni response of '%q'", i.DNS.Nameservers)
 		}
+		if i.DNS.Search != nil {
+			cniSearchDomains = append(cniSearchDomains, i.DNS.Search...)
+			logrus.Debugf("adding search domain(s) from cni response of '%q'", i.DNS.Search)
+		}
 	}
 
 	dns := make([]net.IP, 0, len(c.runtime.config.Containers.DNSServers))
@@ -1797,10 +1802,11 @@ func (c *Container) generateResolvConf() (string, error) {
 	}
 
 	var search []string
-	if len(c.config.DNSSearch) > 0 || len(c.runtime.config.Containers.DNSSearches) > 0 {
+	if len(c.config.DNSSearch) > 0 || len(c.runtime.config.Containers.DNSSearches) > 0 || len(cniSearchDomains) > 0 {
 		if !util.StringInSlice(".", c.config.DNSSearch) {
 			search = c.runtime.config.Containers.DNSSearches
 			search = append(search, c.config.DNSSearch...)
+			search = append(search, cniSearchDomains...)
 		}
 	} else {
 		search = resolvconf.GetSearchDomains(resolv.Content)
diff --git a/test/e2e/run_networking_test.go b/test/e2e/run_networking_test.go
index a6237a49a..0e6e636bc 100644
--- a/test/e2e/run_networking_test.go
+++ b/test/e2e/run_networking_test.go
@@ -766,4 +766,18 @@ var _ = Describe("Podman run networking", func() {
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(BeZero())
 	})
+
+	It("podman run check dnsname adds dns search domain", func() {
+		Skip("needs dnsname#57")
+		net := "dnsname" + stringid.GenerateNonCryptoID()
+		session := podmanTest.Podman([]string{"network", "create", net})
+		session.WaitWithDefaultTimeout()
+		defer podmanTest.removeCNINetwork(net)
+		Expect(session.ExitCode()).To(BeZero())
+
+		session = podmanTest.Podman([]string{"run", "--network", net, ALPINE, "cat", "/etc/resolv.conf"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(BeZero())
+		Expect(session.OutputToString()).To(ContainSubstring("search dns.podman"))
+	})
 })
-- 
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