Filtering duplicate addresses in listen (ticket #2400).

Due to the glibc bug[1], getaddrinfo("localhost") with AI_ADDRCONFIG
on a typical host with glibc and without IPv6 returns two 127.0.0.1
addresses, and therefore "listen localhost:80;" used to result in
"duplicate ... address and port pair" after 4f9b72a229c1.

Fix is to explicitly filter out duplicate addresses returned during
resolution of a name.

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=14969

1 files changed, 14 insertions, 1 deletions

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 28f7d99b4..2647e7cd0 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -3963,7 +3963,7 @@ ngx_http_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 
     ngx_str_t              *value, size;
     ngx_url_t               u;
-    ngx_uint_t              n;
+    ngx_uint_t              n, i;
     ngx_http_listen_opt_t   lsopt;
 
     cscf->listen = 1;
@@ -4289,6 +4289,16 @@ ngx_http_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
     }
 
     for (n = 0; n < u.naddrs; n++) {
+
+        for (i = 0; i < n; i++) {
+            if (ngx_cmp_sockaddr(u.addrs[n].sockaddr, u.addrs[n].socklen,
+                                 u.addrs[i].sockaddr, u.addrs[i].socklen, 0)
+                == NGX_OK)
+            {
+                goto next;
+            }
+        }
+
         lsopt.sockaddr = u.addrs[n].sockaddr;
         lsopt.socklen = u.addrs[n].socklen;
         lsopt.addr_text = u.addrs[n].name;
@@ -4297,6 +4307,9 @@ ngx_http_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
         if (ngx_http_add_listen(cf, cscf, &lsopt) != NGX_OK) {
             return NGX_CONF_ERROR;
         }
+
+    next:
+        continue;
     }
 
     return NGX_CONF_OK;