Add host.containers.internal entry into container's etc/hosts

This change adds the entry `host.containers.internal` to the `/etc/hosts`
file within a new containers filesystem. The ip address is determined by
the containers networking configuration and points to the gateway address
for the containers networking namespace.

Closes #5651

Signed-off-by: Baron Lenardson <lenardson.baron@gmail.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/test/system/500-networking.bats b/test/system/500-networking.bats
index 34220829a..654bd5d8a 100644
--- a/test/system/500-networking.bats
+++ b/test/system/500-networking.bats
@@ -162,6 +162,27 @@ load helpers
     done
 }
 
+@test "podman run with slirp4ns assigns correct gateway address to host.containers.internal" {
+    CIDR="$(random_rfc1918_subnet)"
+    run_podman run --network slirp4netns:cidr="${CIDR}.0/24" \
+                $IMAGE grep 'host.containers.internal' /etc/hosts
+    is "$output"   "${CIDR}.2 host.containers.internal"   "host.containers.internal should be the cidr+2 address"
+}
+
+@test "podman run with slirp4ns adds correct dns address to resolv.conf" {
+    CIDR="$(random_rfc1918_subnet)"
+    run_podman run --network slirp4netns:cidr="${CIDR}.0/24" \
+                $IMAGE grep "${CIDR}" /etc/resolv.conf
+    is "$output"   "nameserver ${CIDR}.3"   "resolv.conf should have slirp4netns cidr+3 as a nameserver"
+}
+
+@test "podman run with slirp4ns assigns correct ip address container" {
+    CIDR="$(random_rfc1918_subnet)"
+    run_podman run --network slirp4netns:cidr="${CIDR}.0/24" \
+                $IMAGE sh -c "ip address | grep ${CIDR}"
+    is "$output"   ".*inet ${CIDR}.100/24 \+"   "container should have slirp4netns cidr+100 assigned to interface"
+}
+
 # "network create" now works rootless, with the help of a special container
 @test "podman network create" {
     myport=54322