From 0c7204e934b8abda433026f9ec9800c5380a657d Mon Sep 17 00:00:00 2001
From: boarchuz <46267286+boarchuz@users.noreply.github.com>
Date: Wed, 17 Jul 2019 18:59:07 +1000
Subject: [PATCH] tcp_transport: Implement connect timeout

Merges https://github.com/espressif/esp-idf/pull/3791
Closes https://github.com/espressif/esp-idf/issues/5004
---
 components/tcp_transport/transport_tcp.c | 58 +++++++++++++++++++++---
 1 file changed, 52 insertions(+), 6 deletions(-)

diff --git a/components/tcp_transport/transport_tcp.c b/components/tcp_transport/transport_tcp.c
index 975d0e8740..6e68991a31 100644
--- a/components/tcp_transport/transport_tcp.c
+++ b/components/tcp_transport/transport_tcp.c
@@ -81,14 +81,60 @@ static int tcp_connect(esp_transport_handle_t t, const char *host, int port, int
     setsockopt(tcp->sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
     setsockopt(tcp->sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
 
-    ESP_LOGD(TAG, "[sock=%d],connecting to server IP:%s,Port:%d...",
-             tcp->sock, ipaddr_ntoa((const ip_addr_t*)&remote_ip.sin_addr.s_addr), port);
-    if (connect(tcp->sock, (struct sockaddr *)(&remote_ip), sizeof(struct sockaddr)) != 0) {
-        close(tcp->sock);
-        tcp->sock = -1;
-        return -1;
+    // Set socket to non-blocking
+    int flags;
+    if ((flags = fcntl(tcp->sock, F_GETFL, NULL)) < 0 || fcntl(tcp->sock, F_SETFL, flags |= O_NONBLOCK) < 0) {
+        ESP_LOGE(TAG, "[sock=%d] set nonblocking error: %s", tcp->sock, strerror(errno));
+        goto error;
+    }
+
+    ESP_LOGD(TAG, "[sock=%d] Connecting to server. IP: %s, Port: %d",
+            tcp->sock, ipaddr_ntoa((const ip_addr_t*)&remote_ip.sin_addr.s_addr), port);
+
+    if (connect(tcp->sock, (struct sockaddr *)(&remote_ip), sizeof(struct sockaddr)) < 0) {
+        if (errno == EINPROGRESS) {
+            fd_set fdset;
+
+            esp_transport_utils_ms_to_timeval(timeout_ms, &tv);
+            FD_ZERO(&fdset);
+            FD_SET(tcp->sock, &fdset);
+
+            int res = select(tcp->sock+1, NULL, &fdset, NULL, &tv);
+            if (res < 0) {
+                ESP_LOGE(TAG, "[sock=%d] select() error: %s", tcp->sock, strerror(errno));
+                goto error;
+            }
+            else if (res == 0) {
+                ESP_LOGE(TAG, "[sock=%d] select() timeout", tcp->sock);
+                goto error;
+            } else {
+                int sockerr;
+                socklen_t len = (socklen_t)sizeof(int);
+
+                if (getsockopt(tcp->sock, SOL_SOCKET, SO_ERROR, (void*)(&sockerr), &len) < 0) {
+                    ESP_LOGE(TAG, "[sock=%d] getsockopt() error: %s", tcp->sock, strerror(errno));
+                    goto error;
+                }
+                else if (sockerr) {
+                    ESP_LOGE(TAG, "[sock=%d] delayed connect error: %s", tcp->sock, strerror(sockerr));
+                    goto error;
+                }
+            }
+        } else {
+            ESP_LOGE(TAG, "[sock=%d] connect() error: %s", tcp->sock, strerror(errno));
+            goto error;
+        }
+    }
+    // Reset socket to blocking
+    if ((flags = fcntl(tcp->sock, F_GETFL, NULL)) < 0 || fcntl(tcp->sock, F_SETFL, flags & ~O_NONBLOCK) < 0) {
+        ESP_LOGE(TAG, "[sock=%d] reset blocking error: %s", tcp->sock, strerror(errno));
+        goto error;
     }
     return tcp->sock;
+error:
+    close(tcp->sock);
+    tcp->sock = -1;
+    return -1;
 }
 
 static int tcp_write(esp_transport_handle_t t, const char *buffer, int len, int timeout_ms)