Fix tcp6 on Travis (kavu#27)

.travis.yml

@@ -1,5 +1,5 @@
-sudo: false
-group: edge
+dist: trusty
+sudo: true
 
 language: go
 
@@ -8,6 +8,7 @@ go:
   - 1.7
   - 1.8
   - 1.9
+  - "1.10"
   - tip
 
 os:
@@ -17,15 +18,12 @@ os:
 before_install:
   - uname -a
 
-script:
-  - go test -v -cover ./...
-  - go test -v -cover -race ./... -coverprofile=coverage.txt -covermode=atomic
-  - go test -v -cover -race -benchmem -benchtime=5s -bench=.
+script: ./test.bash
 
 matrix:
   allow_failures:
     - os: osx
     - go: tip
- 
+
 after_success:
   - bash <(curl -s https://codecov.io/bash)

test.bash

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+set -e
+
+# Thanks to IPFS team
+if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+    if [[ "$TRAVIS_SUDO" == true ]]; then
+        # Ensure that IPv6 is enabled.
+        # While this is unsupported by TravisCI, it still works for localhost.
+        sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=0
+        sudo sysctl -w net.ipv6.conf.default.disable_ipv6=0
+        sudo sysctl -w net.ipv6.conf.all.disable_ipv6=0
+    fi
+else
+    # OSX has a default file limit of 256, for some tests we need a
+    # maximum of 8192.
+    ulimit -Sn 8192
+fi
+
+go test -v -cover ./...
+go test -v -cover -race ./... -coverprofile=coverage.txt -covermode=atomic
+go test -v -cover -race -benchmem -benchtime=5s -bench=.