Fix loopargs_t object duplication into ASYNC context
[openssl.git] / apps / s_socket.c
index 727425744c73efb5c91d5cb3a1c3da4e5adc5ca7..d16f5ad81731cc62e4bf3f9f935de9701da3486e 100644 (file)
-/* apps/s_socket.c -  socket-related functions used by s_client and s_server */
-/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
- * All rights reserved.
+/*
+ * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
  *
- * This package is an SSL implementation written
- * by Eric Young (eay@cryptsoft.com).
- * The implementation was written so as to conform with Netscapes SSL.
- * 
- * This library is free for commercial and non-commercial use as long as
- * the following conditions are aheared to.  The following conditions
- * apply to all code found in this distribution, be it the RC4, RSA,
- * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
- * included with this distribution is covered by the same copyright terms
- * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- * 
- * Copyright remains Eric Young's, and as such any Copyright notices in
- * the code are not to be removed.
- * If this package is used in a product, Eric Young should be given attribution
- * as the author of the parts of the library used.
- * This can be in the form of a textual message at program startup or
- * in documentation (online or textual) provided with the package.
- * 
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *    "This product includes cryptographic software written by
- *     Eric Young (eay@cryptsoft.com)"
- *    The word 'cryptographic' can be left out if the rouines from the library
- *    being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from 
- *    the apps directory (application code) you must include an acknowledgement:
- *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- * 
- * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * 
- * The licence and distribution terms for any publically available version or
- * derivative of this code cannot be changed.  i.e. this code cannot simply be
- * copied and put under another distribution licence
- * [including the GNU Public Licence.]
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
  */
 
+/* socket-related functions used by s_client and s_server */
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <signal.h>
+#include <openssl/opensslconf.h>
 
-/* With IPv6, it looks like Digital has mixed up the proper order of
-   recursive header file inclusion, resulting in the compiler complaining
-   that u_int isn't defined, but only if _POSIX_C_SOURCE is defined, which
-   is needed to have fileno() declared correctly...  So let's define u_int */
+/*
+ * With IPv6, it looks like Digital has mixed up the proper order of
+ * recursive header file inclusion, resulting in the compiler complaining
+ * that u_int isn't defined, but only if _POSIX_C_SOURCE is defined, which is
+ * needed to have fileno() declared correctly...  So let's define u_int
+ */
 #if defined(OPENSSL_SYS_VMS_DECC) && !defined(__U_INT)
-#define __U_INT
+# define __U_INT
 typedef unsigned int u_int;
 #endif
 
-#define USE_SOCKETS
-#define NON_MAIN
-#include "apps.h"
-#undef USE_SOCKETS
-#undef NON_MAIN
-#include "s_apps.h"
-#include <openssl/ssl.h>
-
-#ifdef FLAT_INC
-#include "e_os.h"
-#else
-#include "../e_os.h"
-#endif
-
 #ifndef OPENSSL_NO_SOCK
 
-static struct hostent *GetHostByName(char *name);
-#if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_NETWARE)
-static void ssl_sock_cleanup(void);
-#endif
-static int ssl_sock_init(void);
-static int init_client_ip(int *sock,unsigned char ip[4], int port);
-static int init_server(int *sock, int port);
-static int init_server_long(int *sock, int port,char *ip);
-static int do_accept(int acc_sock, int *sock, char **host);
-static int host_ip(char *str, unsigned char ip[4]);
-
-#ifdef OPENSSL_SYS_WIN16
-#define SOCKET_PROTOCOL        0 /* more microsoft stupidity */
-#else
-#define SOCKET_PROTOCOL        IPPROTO_TCP
-#endif
-
-#ifdef OPENSSL_SYS_NETWARE
-static int wsa_init_done=0;
-#endif
-
-#ifdef OPENSSL_SYS_WINDOWS
-static struct WSAData wsa_state;
-static int wsa_init_done=0;
-
-#ifdef OPENSSL_SYS_WIN16
-static HWND topWnd=0;
-static FARPROC lpTopWndProc=NULL;
-static FARPROC lpTopHookProc=NULL;
-extern HINSTANCE _hInstance;  /* nice global CRT provides */
-
-static LONG FAR PASCAL topHookProc(HWND hwnd, UINT message, WPARAM wParam,
-            LPARAM lParam)
-       {
-       if (hwnd == topWnd)
-               {
-               switch(message)
-                       {
-               case WM_DESTROY:
-               case WM_CLOSE:
-                       SetWindowLong(topWnd,GWL_WNDPROC,(LONG)lpTopWndProc);
-                       ssl_sock_cleanup();
-                       break;
-                       }
-               }
-       return CallWindowProc(lpTopWndProc,hwnd,message,wParam,lParam);
-       }
-
-static BOOL CALLBACK enumproc(HWND hwnd,LPARAM lParam)
-       {
-       topWnd=hwnd;
-       return(FALSE);
-       }
-
-#endif /* OPENSSL_SYS_WIN32 */
-#endif /* OPENSSL_SYS_WINDOWS */
-
-#ifdef OPENSSL_SYS_WINDOWS
-static void ssl_sock_cleanup(void)
-       {
-       if (wsa_init_done)
-               {
-               wsa_init_done=0;
-#ifndef OPENSSL_SYS_WINCE
-               WSACancelBlockingCall();
-#endif
-               WSACleanup();
-               }
-       }
-#elif defined(OPENSSL_SYS_NETWARE)
-static void sock_cleanup(void)
-    {
-    if (wsa_init_done)
-        {
-        wsa_init_done=0;
-               WSACleanup();
-               }
-       }
-#endif
-
-static int ssl_sock_init(void)
-       {
-#ifdef WATT32
-       extern int _watt_do_exit;
-       _watt_do_exit = 0;
-       if (sock_init())
-               return (0);
-#elif defined(OPENSSL_SYS_WINDOWS)
-       if (!wsa_init_done)
-               {
-               int err;
-         
-#ifdef SIGINT
-               signal(SIGINT,(void (*)(int))ssl_sock_cleanup);
-#endif
-               wsa_init_done=1;
-               memset(&wsa_state,0,sizeof(wsa_state));
-               if (WSAStartup(0x0101,&wsa_state)!=0)
-                       {
-                       err=WSAGetLastError();
-                       BIO_printf(bio_err,"unable to start WINSOCK, error code=%d\n",err);
-                       return(0);
-                       }
-
-#ifdef OPENSSL_SYS_WIN16
-               EnumTaskWindows(GetCurrentTask(),enumproc,0L);
-               lpTopWndProc=(FARPROC)GetWindowLong(topWnd,GWL_WNDPROC);
-               lpTopHookProc=MakeProcInstance((FARPROC)topHookProc,_hInstance);
-
-               SetWindowLong(topWnd,GWL_WNDPROC,(LONG)lpTopHookProc);
-#endif /* OPENSSL_SYS_WIN16 */
-               }
-#elif defined(OPENSSL_SYS_NETWARE)
-   WORD wVerReq;
-   WSADATA wsaData;
-   int err;
-
-   if (!wsa_init_done)
-      {
-   
-# ifdef SIGINT
-      signal(SIGINT,(void (*)(int))sock_cleanup);
-# endif
-
-      wsa_init_done=1;
-      wVerReq = MAKEWORD( 2, 0 );
-      err = WSAStartup(wVerReq,&wsaData);
-      if (err != 0)
-         {
-         BIO_printf(bio_err,"unable to start WINSOCK2, error code=%d\n",err);
-         return(0);
-         }
-      }
-#endif /* OPENSSL_SYS_WINDOWS */
-       return(1);
-       }
-
-int init_client(int *sock, char *host, int port)
-       {
-       unsigned char ip[4];
-       short p=0;
-
-       if (!host_ip(host,&(ip[0])))
-               {
-               return(0);
-               }
-       if (p != 0) port=p;
-       return(init_client_ip(sock,ip,port));
-       }
-
-static int init_client_ip(int *sock, unsigned char ip[4], int port)
-       {
-       unsigned long addr;
-       struct sockaddr_in them;
-       int s,i;
-
-       if (!ssl_sock_init()) return(0);
-
-       memset((char *)&them,0,sizeof(them));
-       them.sin_family=AF_INET;
-       them.sin_port=htons((unsigned short)port);
-       addr=(unsigned long)
-               ((unsigned long)ip[0]<<24L)|
-               ((unsigned long)ip[1]<<16L)|
-               ((unsigned long)ip[2]<< 8L)|
-               ((unsigned long)ip[3]);
-       them.sin_addr.s_addr=htonl(addr);
-
-       s=socket(AF_INET,SOCK_STREAM,SOCKET_PROTOCOL);
-       if (s == INVALID_SOCKET) { perror("socket"); return(0); }
-
-#ifndef OPENSSL_SYS_MPE
-       i=0;
-       i=setsockopt(s,SOL_SOCKET,SO_KEEPALIVE,(char *)&i,sizeof(i));
-       if (i < 0) { perror("keepalive"); return(0); }
-#endif
-
-       if (connect(s,(struct sockaddr *)&them,sizeof(them)) == -1)
-               { close(s); perror("connect"); return(0); }
-       *sock=s;
-       return(1);
-       }
-
-int do_server(int port, int *ret, int (*cb)(char *hostname, int s, unsigned char *context), char *context)
-       {
-       int sock;
-       char *name;
-       int accept_socket;
-       int i;
-
-       if (!init_server(&accept_socket,port)) return(0);
-
-       if (ret != NULL)
-               {
-               *ret=accept_socket;
-               /* return(1);*/
-               }
-       for (;;)
-               {
-               if (do_accept(accept_socket,&sock,&name) == 0)
-                       {
-                       SHUTDOWN(accept_socket);
-                       return(0);
-                       }
-               i=(*cb)(name,sock, context);
-               if (name != NULL) OPENSSL_free(name);
-               SHUTDOWN2(sock);
-               if (i < 0)
-                       {
-                       SHUTDOWN2(accept_socket);
-                       return(i);
-                       }
-               }
-       }
-
-static int init_server_long(int *sock, int port, char *ip)
-       {
-       int ret=0;
-       struct sockaddr_in server;
-       int s= -1,i;
+# define USE_SOCKETS
+# include "apps.h"
+# undef USE_SOCKETS
+# include "s_apps.h"
 
-       if (!ssl_sock_init()) return(0);
-
-       memset((char *)&server,0,sizeof(server));
-       server.sin_family=AF_INET;
-       server.sin_port=htons((unsigned short)port);
-       if (ip == NULL)
-               server.sin_addr.s_addr=INADDR_ANY;
-       else
-/* Added for T3E, address-of fails on bit field (beckman@acl.lanl.gov) */
-#ifndef BIT_FIELD_LIMITS
-               memcpy(&server.sin_addr.s_addr,ip,4);
-#else
-               memcpy(&server.sin_addr,ip,4);
-#endif
-       s=socket(AF_INET,SOCK_STREAM,SOCKET_PROTOCOL);
-
-       if (s == INVALID_SOCKET) goto err;
-#if defined SOL_SOCKET && defined SO_REUSEADDR
-               {
-               int j = 1;
-               setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
-                          (void *) &j, sizeof j);
-               }
-#endif
-       if (bind(s,(struct sockaddr *)&server,sizeof(server)) == -1)
-               {
-#ifndef OPENSSL_SYS_WINDOWS
-               perror("bind");
-#endif
-               goto err;
-               }
-       /* Make it 128 for linux */
-       if (listen(s,128) == -1) goto err;
-       i=0;
-       *sock=s;
-       ret=1;
-err:
-       if ((ret == 0) && (s != -1))
-               {
-               SHUTDOWN(s);
-               }
-       return(ret);
-       }
-
-static int init_server(int *sock, int port)
-       {
-       return(init_server_long(sock, port, NULL));
-       }
-
-static int do_accept(int acc_sock, int *sock, char **host)
-       {
-       int ret,i;
-       struct hostent *h1,*h2;
-       static struct sockaddr_in from;
-       int len;
-/*     struct linger ling; */
-
-       if (!ssl_sock_init()) return(0);
-
-#ifndef OPENSSL_SYS_WINDOWS
-redoit:
-#endif
-
-       memset((char *)&from,0,sizeof(from));
-       len=sizeof(from);
-       /* Note: under VMS with SOCKETSHR the fourth parameter is currently
-        * of type (int *) whereas under other systems it is (void *) if
-        * you don't have a cast it will choke the compiler: if you do
-        * have a cast then you can either go for (int *) or (void *).
-        */
-       ret=accept(acc_sock,(struct sockaddr *)&from,(void *)&len);
-       if (ret == INVALID_SOCKET)
-               {
-#if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_NETWARE)
-               i=WSAGetLastError();
-               BIO_printf(bio_err,"accept error %d\n",i);
-#else
-               if (errno == EINTR)
-                       {
-                       /*check_timeout(); */
-                       goto redoit;
-                       }
-               fprintf(stderr,"errno=%d ",errno);
-               perror("accept");
-#endif
-               return(0);
-               }
+# include <openssl/bio.h>
+# include <openssl/err.h>
 
 /*
-       ling.l_onoff=1;
-       ling.l_linger=0;
-       i=setsockopt(ret,SOL_SOCKET,SO_LINGER,(char *)&ling,sizeof(ling));
-       if (i < 0) { perror("linger"); return(0); }
-       i=0;
-       i=setsockopt(ret,SOL_SOCKET,SO_KEEPALIVE,(char *)&i,sizeof(i));
-       if (i < 0) { perror("keepalive"); return(0); }
-*/
-
-       if (host == NULL) goto end;
-#ifndef BIT_FIELD_LIMITS
-       /* I should use WSAAsyncGetHostByName() under windows */
-       h1=gethostbyaddr((char *)&from.sin_addr.s_addr,
-               sizeof(from.sin_addr.s_addr),AF_INET);
-#else
-       h1=gethostbyaddr((char *)&from.sin_addr,
-               sizeof(struct in_addr),AF_INET);
-#endif
-       if (h1 == NULL)
-               {
-               BIO_printf(bio_err,"bad gethostbyaddr\n");
-               *host=NULL;
-               /* return(0); */
-               }
-       else
-               {
-               if ((*host=(char *)OPENSSL_malloc(strlen(h1->h_name)+1)) == NULL)
-                       {
-                       perror("OPENSSL_malloc");
-                       return(0);
-                       }
-               BUF_strlcpy(*host,h1->h_name,strlen(h1->h_name)+1);
-
-               h2=GetHostByName(*host);
-               if (h2 == NULL)
-                       {
-                       BIO_printf(bio_err,"gethostbyname failure\n");
-                       return(0);
-                       }
-               i=0;
-               if (h2->h_addrtype != AF_INET)
-                       {
-                       BIO_printf(bio_err,"gethostbyname addr is not AF_INET\n");
-                       return(0);
-                       }
-               }
-end:
-       *sock=ret;
-       return(1);
-       }
-
-int extract_host_port(char *str, char **host_ptr, unsigned char *ip,
-            short *port_ptr)
-       {
-       char *h,*p;
-
-       h=str;
-       p=strchr(str,':');
-       if (p == NULL)
-               {
-               BIO_printf(bio_err,"no port defined\n");
-               return(0);
-               }
-       *(p++)='\0';
-
-       if ((ip != NULL) && !host_ip(str,ip))
-               goto err;
-       if (host_ptr != NULL) *host_ptr=h;
-
-       if (!extract_port(p,port_ptr))
-               goto err;
-       return(1);
-err:
-       return(0);
-       }
-
-static int host_ip(char *str, unsigned char ip[4])
-       {
-       unsigned int in[4]; 
-       int i;
-
-       if (sscanf(str,"%u.%u.%u.%u",&(in[0]),&(in[1]),&(in[2]),&(in[3])) == 4)
-               {
-               for (i=0; i<4; i++)
-                       if (in[i] > 255)
-                               {
-                               BIO_printf(bio_err,"invalid IP address\n");
-                               goto err;
-                               }
-               ip[0]=in[0];
-               ip[1]=in[1];
-               ip[2]=in[2];
-               ip[3]=in[3];
-               }
-       else
-               { /* do a gethostbyname */
-               struct hostent *he;
-
-               if (!ssl_sock_init()) return(0);
-
-               he=GetHostByName(str);
-               if (he == NULL)
-                       {
-                       BIO_printf(bio_err,"gethostbyname failure\n");
-                       goto err;
-                       }
-               /* cast to short because of win16 winsock definition */
-               if ((short)he->h_addrtype != AF_INET)
-                       {
-                       BIO_printf(bio_err,"gethostbyname addr is not AF_INET\n");
-                       return(0);
-                       }
-               ip[0]=he->h_addr_list[0][0];
-               ip[1]=he->h_addr_list[0][1];
-               ip[2]=he->h_addr_list[0][2];
-               ip[3]=he->h_addr_list[0][3];
-               }
-       return(1);
-err:
-       return(0);
-       }
-
-int extract_port(char *str, short *port_ptr)
-       {
-       int i;
-       struct servent *s;
-
-       i=atoi(str);
-       if (i != 0)
-               *port_ptr=(unsigned short)i;
-       else
-               {
-               s=getservbyname(str,"tcp");
-               if (s == NULL)
-                       {
-                       BIO_printf(bio_err,"getservbyname failure for %s\n",str);
-                       return(0);
-                       }
-               *port_ptr=ntohs((unsigned short)s->s_port);
-               }
-       return(1);
-       }
-
-#define GHBN_NUM       4
-static struct ghbn_cache_st
-       {
-       char name[128];
-       struct hostent ent;
-       unsigned long order;
-       } ghbn_cache[GHBN_NUM];
-
-static unsigned long ghbn_hits=0L;
-static unsigned long ghbn_miss=0L;
-
-static struct hostent *GetHostByName(char *name)
-       {
-       struct hostent *ret;
-       int i,lowi=0;
-       unsigned long low= (unsigned long)-1;
+ * init_client - helper routine to set up socket communication
+ * @sock: pointer to storage of resulting socket.
+ * @host: the host name or path (for AF_UNIX) to connect to.
+ * @port: the port to connect to (ignored for AF_UNIX).
+ * @family: desired socket family, may be AF_INET, AF_INET6, AF_UNIX or
+ *  AF_UNSPEC
+ * @type: socket type, must be SOCK_STREAM or SOCK_DGRAM
+ *
+ * This will create a socket and use it to connect to a host:port, or if
+ * family == AF_UNIX, to the path found in host.
+ *
+ * If the host has more than one address, it will try them one by one until
+ * a successful connection is established.  The resulting socket will be
+ * found in *sock on success, it will be given INVALID_SOCKET otherwise.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int init_client(int *sock, const char *host, const char *port,
+                int family, int type)
+{
+    BIO_ADDRINFO *res = NULL;
+    const BIO_ADDRINFO *ai = NULL;
+    int ret;
+
+    if (!BIO_sock_init())
+        return 0;
+
+    ret = BIO_lookup(host, port, BIO_LOOKUP_CLIENT, family, type, &res);
+    if (ret == 0) {
+        ERR_print_errors(bio_err);
+        return 0;
+    }
+
+    ret = 0;
+    for (ai = res; ai != NULL; ai = BIO_ADDRINFO_next(ai)) {
+        /* Admittedly, these checks are quite paranoid, we should not get
+         * anything in the BIO_ADDRINFO chain that we haven't
+         * asked for. */
+        OPENSSL_assert((family == AF_UNSPEC || family == BIO_ADDRINFO_family(res))
+                       && (type == 0 || type == BIO_ADDRINFO_socktype(res)));
+
+        *sock = BIO_socket(BIO_ADDRINFO_family(ai), BIO_ADDRINFO_socktype(ai),
+                           BIO_ADDRINFO_protocol(res), 0);
+        if (*sock == INVALID_SOCKET) {
+            /* Maybe the kernel doesn't support the socket family, even if
+             * BIO_lookup() added it in the returned result...
+             */
+            continue;
+        }
+        if (!BIO_connect(*sock, BIO_ADDRINFO_address(ai), 0)) {
+            BIO_closesocket(*sock);
+            *sock = INVALID_SOCKET;
+            continue;
+        }
+
+        /* Success, don't try any more addresses */
+        break;
+    }
+
+    if (*sock == INVALID_SOCKET) {
+        ERR_print_errors(bio_err);
+    } else {
+        /* Remove any stale errors from previous connection attempts */
+        ERR_clear_error();
+        ret = 1;
+    }
+    BIO_ADDRINFO_free(res);
+    return ret;
+}
 
-       for (i=0; i<GHBN_NUM; i++)
-               {
-               if (low > ghbn_cache[i].order)
-                       {
-                       low=ghbn_cache[i].order;
-                       lowi=i;
-                       }
-               if (ghbn_cache[i].order > 0)
-                       {
-                       if (strncmp(name,ghbn_cache[i].name,128) == 0)
-                               break;
-                       }
-               }
-       if (i == GHBN_NUM) /* no hit*/
-               {
-               ghbn_miss++;
-               ret=gethostbyname(name);
-               if (ret == NULL) return(NULL);
-               /* else add to cache */
-               if(strlen(name) < sizeof ghbn_cache[0].name)
-                       {
-                       strcpy(ghbn_cache[lowi].name,name);
-                       memcpy((char *)&(ghbn_cache[lowi].ent),ret,sizeof(struct hostent));
-                       ghbn_cache[lowi].order=ghbn_miss+ghbn_hits;
-                       }
-               return(ret);
-               }
-       else
-               {
-               ghbn_hits++;
-               ret= &(ghbn_cache[i].ent);
-               ghbn_cache[i].order=ghbn_miss+ghbn_hits;
-               return(ret);
-               }
-       }
+/*
+ * do_server - helper routine to perform a server operation
+ * @accept_sock: pointer to storage of resulting socket.
+ * @host: the host name or path (for AF_UNIX) to connect to.
+ * @port: the port to connect to (ignored for AF_UNIX).
+ * @family: desired socket family, may be AF_INET, AF_INET6, AF_UNIX or
+ *  AF_UNSPEC
+ * @type: socket type, must be SOCK_STREAM or SOCK_DGRAM
+ * @cb: pointer to a function that receives the accepted socket and
+ *  should perform the communication with the connecting client.
+ * @context: pointer to memory that's passed verbatim to the cb function.
+ * @naccept: number of times an incoming connect should be accepted.  If -1,
+ *  unlimited number.
+ *
+ * This will create a socket and use it to listen to a host:port, or if
+ * family == AF_UNIX, to the path found in host, then start accepting
+ * incoming connections and run cb on the resulting socket.
+ *
+ * 0 on failure, something other on success.
+ */
+int do_server(int *accept_sock, const char *host, const char *port,
+              int family, int type, do_server_cb cb,
+              unsigned char *context, int naccept)
+{
+    int asock = 0;
+    int sock;
+    int i;
+    BIO_ADDRINFO *res = NULL;
+    int ret = 0;
+
+    if (!BIO_sock_init())
+        return 0;
+
+    if (!BIO_lookup(host, port, BIO_LOOKUP_SERVER, family, type, &res)) {
+        ERR_print_errors(bio_err);
+        return 0;
+    }
+
+    /* Admittedly, these checks are quite paranoid, we should not get
+     * anything in the BIO_ADDRINFO chain that we haven't asked for */
+    OPENSSL_assert((family == AF_UNSPEC || family == BIO_ADDRINFO_family(res))
+                   && (type == 0 || type == BIO_ADDRINFO_socktype(res)));
+
+    asock = BIO_socket(BIO_ADDRINFO_family(res), BIO_ADDRINFO_socktype(res),
+                       BIO_ADDRINFO_protocol(res), 0);
+    if (asock == INVALID_SOCKET
+        || !BIO_listen(asock, BIO_ADDRINFO_address(res), BIO_SOCK_REUSEADDR)) {
+        BIO_ADDRINFO_free(res);
+        ERR_print_errors(bio_err);
+        if (asock != INVALID_SOCKET)
+            BIO_closesocket(asock);
+        goto end;
+    }
+
+    BIO_ADDRINFO_free(res);
+    res = NULL;
+
+    if (accept_sock != NULL)
+        *accept_sock = asock;
+    for (;;) {
+        if (type == SOCK_STREAM) {
+            do {
+                sock = BIO_accept_ex(asock, NULL, 0);
+            } while (sock < 0 && BIO_sock_should_retry(ret));
+            if (sock < 0) {
+                ERR_print_errors(bio_err);
+                BIO_closesocket(asock);
+                break;
+            }
+            i = (*cb)(sock, type, context);
+            BIO_closesocket(sock);
+        } else {
+            i = (*cb)(asock, type, context);
+        }
+
+        if (naccept != -1)
+            naccept--;
+        if (i < 0 || naccept == 0) {
+            BIO_closesocket(asock);
+            ret = i;
+            break;
+        }
+    }
+ end:
+# ifdef AF_UNIX
+    if (family == AF_UNIX)
+        unlink(host);
+# endif
+    return ret;
+}
 
-#endif
+#endif  /* OPENSSL_NO_SOCK */