perf: reuse_port must be called explicitly

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

example/multi_process_server_reuseport.c

@@ -77,6 +77,8 @@ static void start_server(const char *addr, const char *docroot)
     if (!srv)
         return;
 
+    srv->reuse_port(srv, true);
+
     if (srv->listen(srv, addr, false) < 0)
         return;
 

src/uhttpd.c

@@ -344,6 +344,13 @@ static void uh_set_loop(struct uh_server *srv, struct ev_loop *loop)
     srvi->loop = loop;
 }
 
+static void uh_reuse_port(struct uh_server *srv, bool val)
+{
+    struct uh_server_internal *srvi = (struct uh_server_internal *)srv;
+
+    srvi->reuse_port = val;
+}
+
 static int parse_address(const char *addr, char **host, char **port)
 {
     static char buf[256];
@@ -420,11 +427,14 @@ static int uh_server_listen(struct uh_server *srv, const char *addr, bool ssl)
 
         /* required to get parallel v4 + v6 working */
         if (p->ai_family == AF_INET6 && setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(int)) < 0) {
-            log_err("setsockopt: %s\n", strerror(errno));
+            log_err("setsockopt: IPV6_V6ONLY: %s\n", strerror(errno));
             goto err;
         }
 
-        setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(int));
+        if (srvi->reuse_port && setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(int))) {
+            log_err("setsockopt: SO_REUSEPORT: %s\n", strerror(errno));
+            goto err;
+        }
 
         if (bind(sock, p->ai_addr, p->ai_addrlen) < 0) {
             log_err("bind: %s\n", strerror(errno));
@@ -492,6 +502,7 @@ void uh_server_init(struct uh_server *srv, struct ev_loop *loop)
     srv->set_loop = uh_set_loop;
     srv->free = uh_server_free;
 
+    srv->reuse_port = uh_reuse_port;
     srv->listen = uh_server_listen;
 
 #ifdef SSL_SUPPORT

src/uhttpd.h

@@ -155,6 +155,7 @@ struct uh_server {
     /* Replace the existing loop. Can only be called before calling the listen */
     void (*set_loop)(struct uh_server *srv, struct ev_loop *loop);
     void (*free)(struct uh_server *srv);
+    void (*reuse_port)(struct uh_server *srv, bool val);
     /*
     ** listen an address, multiple call allowed
     ** returns the number of successful listen

src/uhttpd_internal.h

@@ -66,6 +66,7 @@ struct uh_server_internal {
     struct uh_server com;
     char *docroot;
     char *index_page;
+    bool reuse_port;
     bool https_redirect;
     struct ev_loop *loop;
     void (*conn_closed_cb)(struct uh_connection *conn);