From 78cc20f00730c5f017550bec2e494523bc052c42 Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Thu, 1 Sep 2016 14:54:18 -0700
Subject: [PATCH] libcutils: try all addresses in
 socket_network_client_timeout.

If a connection fails to an address that resolves to multiple
sockaddrs, attempt connecting to subsequent addresses if the initial
connection fails to a reason other than timeout. This is primarily
useful for localhost, which can resolve to both an IPv4 and and IPv6
address.

Also, add an adb test to verify that this behavior.

Bug: http://b/30313466
Change-Id: Ib2df706a66cf6ef8c1097fdfd7aedb69b8df2d6e
Test: python test_adb.py (+ the test fails before this patch)
---
 adb/test_adb.py                        |  22 +++++
 libcutils/socket_network_client_unix.c | 111 ++++++++++++-------------
 2 files changed, 77 insertions(+), 56 deletions(-)

diff --git a/adb/test_adb.py b/adb/test_adb.py
index 0f1b034d8..cb3e0d85e 100644
--- a/adb/test_adb.py
+++ b/adb/test_adb.py
@@ -207,6 +207,28 @@ class NonApiTest(unittest.TestCase):
             # reading the response from the adb emu kill command (on Windows).
             self.assertEqual(0, p.returncode)
 
+    def test_connect_ipv4_ipv6(self):
+        """Ensure that `adb connect localhost:1234` will try both IPv4 and IPv6.
+
+        Bug: http://b/30313466
+        """
+        ipv4 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        ipv4.bind(('127.0.0.1', 0))
+        ipv4.listen(1)
+
+        ipv6 = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+        ipv6.bind(('::1', ipv4.getsockname()[1] + 1))
+        ipv6.listen(1)
+
+        for s in (ipv4, ipv6):
+            port = s.getsockname()[1]
+            output = subprocess.check_output(
+                ['adb', 'connect', 'localhost:{}'.format(port)])
+
+            self.assertEqual(
+                output.strip(), 'connected to localhost:{}'.format(port))
+            s.close()
+
 
 def main():
     random.seed(0)
diff --git a/libcutils/socket_network_client_unix.c b/libcutils/socket_network_client_unix.c
index 3300b8fb1..46818d695 100644
--- a/libcutils/socket_network_client_unix.c
+++ b/libcutils/socket_network_client_unix.c
@@ -59,64 +59,63 @@ int socket_network_client_timeout(const char* host, int port, int type, int time
         return -1;
     }
 
-    // TODO: try all the addresses if there's more than one?
-    int family = addrs[0].ai_family;
-    int protocol = addrs[0].ai_protocol;
-    socklen_t addr_len = addrs[0].ai_addrlen;
-    struct sockaddr_storage addr;
-    memcpy(&addr, addrs[0].ai_addr, addr_len);
+    int result = -1;
+    for (struct addrinfo* addr = addrs; addr != NULL; addr = addr->ai_next) {
+        // The Mac doesn't have SOCK_NONBLOCK.
+        int s = socket(addr->ai_family, type, addr->ai_protocol);
+        if (s == -1 || toggle_O_NONBLOCK(s) == -1) return -1;
+
+        int rc = connect(s, addr->ai_addr, addr->ai_addrlen);
+        if (rc == 0) {
+            result = toggle_O_NONBLOCK(s);
+            break;
+        } else if (rc == -1 && errno != EINPROGRESS) {
+            close(s);
+            continue;
+        }
+
+        fd_set r_set;
+        FD_ZERO(&r_set);
+        FD_SET(s, &r_set);
+        fd_set w_set = r_set;
+
+        struct timeval ts;
+        ts.tv_sec = timeout;
+        ts.tv_usec = 0;
+        if ((rc = select(s + 1, &r_set, &w_set, NULL, (timeout != 0) ? &ts : NULL)) == -1) {
+            close(s);
+            break;
+        }
+        if (rc == 0) {  // we had a timeout
+            errno = ETIMEDOUT;
+            close(s);
+            break;
+        }
+
+        int error = 0;
+        socklen_t len = sizeof(error);
+        if (FD_ISSET(s, &r_set) || FD_ISSET(s, &w_set)) {
+            if (getsockopt(s, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
+                close(s);
+                break;
+            }
+        } else {
+            close(s);
+            break;
+        }
+
+        if (error) {  // check if we had a socket error
+            // TODO: Update the timeout.
+            errno = error;
+            close(s);
+            continue;
+        }
+
+        result = toggle_O_NONBLOCK(s);
+    }
 
     freeaddrinfo(addrs);
-
-    // The Mac doesn't have SOCK_NONBLOCK.
-    int s = socket(family, type, protocol);
-    if (s == -1 || toggle_O_NONBLOCK(s) == -1) return -1;
-
-    int rc = connect(s, (const struct sockaddr*) &addr, addr_len);
-    if (rc == 0) {
-        return toggle_O_NONBLOCK(s);
-    } else if (rc == -1 && errno != EINPROGRESS) {
-        close(s);
-        return -1;
-    }
-
-    fd_set r_set;
-    FD_ZERO(&r_set);
-    FD_SET(s, &r_set);
-    fd_set w_set = r_set;
-
-    struct timeval ts;
-    ts.tv_sec = timeout;
-    ts.tv_usec = 0;
-    if ((rc = select(s + 1, &r_set, &w_set, NULL, (timeout != 0) ? &ts : NULL)) == -1) {
-        close(s);
-        return -1;
-    }
-    if (rc == 0) {   // we had a timeout
-        errno = ETIMEDOUT;
-        close(s);
-        return -1;
-    }
-
-    int error = 0;
-    socklen_t len = sizeof(error);
-    if (FD_ISSET(s, &r_set) || FD_ISSET(s, &w_set)) {
-        if (getsockopt(s, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
-            close(s);
-            return -1;
-        }
-    } else {
-        close(s);
-        return -1;
-    }
-
-    if (error) {  // check if we had a socket error
-        errno = error;
-        close(s);
-        return -1;
-    }
-
-    return toggle_O_NONBLOCK(s);
+    return result;
 }
 
 int socket_network_client(const char* host, int port, int type) {