From c31ffc40e41d163388c250f5cc57f5a6345adf92 Mon Sep 17 00:00:00 2001
From: winlin <winlin@vip.126.com>
Date: Sat, 9 May 2020 10:53:52 +0800
Subject: [PATCH] Support filter RTC candidate by ip family, ipv4 by default.

---
 trunk/conf/full.conf               |  7 ++++++
 trunk/src/app/srs_app_config.cpp   | 20 +++++++++++++++-
 trunk/src/app/srs_app_config.hpp   |  1 +
 trunk/src/app/srs_app_rtc_conn.cpp | 38 ++++++++++++++++++++++++++++++
 4 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/trunk/conf/full.conf b/trunk/conf/full.conf
index b10ad8bf9..0b079133f 100644
--- a/trunk/conf/full.conf
+++ b/trunk/conf/full.conf
@@ -421,6 +421,13 @@ rtc_server {
     #       $CANDIDATE $EIP # TODO: Implements it.
     # default: *
     candidate       *;
+    # The IP family filter for candidate, it can be:
+    #       ipv4        Filter IP v4 candidates.
+    #       ipv6        Filter IP v6 candidates.
+    #       all         Filter all IP v4 or v6 candidates.
+    # For example, if set to ipv4, we only use the IPv4 address as candidate.
+    # default: ipv4
+    ip_family        ipv4;
     # Whether use ECDSA certificate.
     # If not, use RSA certificate.
     # default: on
diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index a2bb2b55e..0603b7a4b 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -3645,7 +3645,8 @@ srs_error_t SrsConfig::check_normal_config()
             string n = conf->at(i)->name;
             if (n != "enabled" && n != "listen" && n != "dir" && n != "candidate" && n != "ecdsa"
                 && n != "sendmmsg" && n != "encrypt" && n != "reuseport" && n != "gso" && n != "merge_nalus"
-                && n != "padding" && n != "perf_stat" && n != "queue_length" && n != "black_hole") {
+                && n != "padding" && n != "perf_stat" && n != "queue_length" && n != "black_hole"
+                && n != "ip_family") {
                 return srs_error_new(ERROR_SYSTEM_CONFIG_INVALID, "illegal rtc_server.%s", n.c_str());
             }
         }
@@ -4747,6 +4748,23 @@ std::string SrsConfig::get_rtc_server_candidates()
     return conf->arg0();
 }
 
+std::string SrsConfig::get_rtc_server_ip_family()
+{
+    static string DEFAULT = "ipv4";
+
+    SrsConfDirective* conf = root->get("rtc_server");
+    if (!conf) {
+        return DEFAULT;
+    }
+
+    conf = conf->get("ip_family");
+    if (!conf || conf->arg0().empty()) {
+        return DEFAULT;
+    }
+
+    return conf->arg0();
+}
+
 bool SrsConfig::get_rtc_server_ecdsa()
 {
     static bool DEFAULT = true;
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 212143001..18f0be51c 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -525,6 +525,7 @@ public:
     virtual bool get_rtc_server_enabled(SrsConfDirective* conf);
     virtual int get_rtc_server_listen();
     virtual std::string get_rtc_server_candidates();
+    virtual std::string get_rtc_server_ip_family();
     virtual bool get_rtc_server_ecdsa();
     virtual int get_rtc_server_sendmmsg();
     virtual bool get_rtc_server_encrypt();
diff --git a/trunk/src/app/srs_app_rtc_conn.cpp b/trunk/src/app/srs_app_rtc_conn.cpp
index e26e62229..fb0ad93ec 100644
--- a/trunk/src/app/srs_app_rtc_conn.cpp
+++ b/trunk/src/app/srs_app_rtc_conn.cpp
@@ -118,13 +118,51 @@ static std::vector<std::string> get_candidate_ips()
 
     // For * or 0.0.0.0, auto discovery expose ip addresses.
     std::vector<SrsIPAddress*>& ips = srs_get_local_ips();
+    if (ips.empty()) {
+        return candidate_ips;
+    }
+
+    // We try to find the best match candidates, no loopback.
+    string family = _srs_config->get_rtc_server_ip_family();
     for (int i = 0; i < (int)ips.size(); ++i) {
         SrsIPAddress* ip = ips[i];
         if (!ip->is_loopback) {
             continue;
         }
 
+        if (family == "ipv4" && !ip->is_ipv4) {
+            continue;
+        }
+        if (family == "ipv6" && ip->is_ipv4) {
+            continue;
+        }
+
         candidate_ips.push_back(ip->ip);
+        srs_warn("Best matched ip=%s, ifname=%s", ip->ip.c_str(), ip->ifname.c_str());
+    }
+
+    if (!candidate_ips.empty()) {
+        return candidate_ips;
+    }
+
+    // Then, we use the ipv4 address.
+    for (int i = 0; i < (int)ips.size(); ++i) {
+        SrsIPAddress* ip = ips[i];
+        if (!ip->is_ipv4) {
+            continue;
+        }
+
+        candidate_ips.push_back(ip->ip);
+        srs_warn("No best matched, use first ip=%s, ifname=%s", ip->ip.c_str(), ip->ifname.c_str());
+        return candidate_ips;
+    }
+
+    // We use the first one.
+    if (candidate_ips.empty()) {
+        SrsIPAddress* ip = ips[0];
+        candidate_ips.push_back(ip->ip);
+        srs_warn("No best matched, use first ip=%s, ifname=%s", ip->ip.c_str(), ip->ifname.c_str());
+        return candidate_ips;
     }
 
     return candidate_ips;