Apply the author's fix for socket binding in the case where

net.inet6.ip6.v6only is set.  This sysctl disables AF_INET6 wildcard
listeners from accepting IPv4 traffic.

3 files changed, 531 insertions, 15 deletions

diff --git a/mail/exim-devel/files/patch-src::daemon.c b/mail/exim-devel/files/patch-src::daemon.c
index b792bbf3529c..72ee5952dd6f 100644
--- a/mail/exim-devel/files/patch-src::daemon.c
+++ b/mail/exim-devel/files/patch-src::daemon.c
@@ -1,17 +1,189 @@
 --- src/daemon.c.orig	Tue Jul 10 11:52:32 2001
 +++ src/daemon.c	Tue Jul 10 11:53:33 2001
-@@ -841,7 +841,13 @@
+@@ -661,7 +661,7 @@
+   union sockaddr_46 sin;
+ 
+   #if HAVE_IPV6
+-  struct in6_addr anyaddr6 = IN6ADDR_ANY_INIT;
++  struct in6_addr anyaddr6 = in6addr_any;
+   #endif
+ 
+   /* Find the standard SMTP port if no port number given; otherwise
+@@ -690,7 +690,11 @@
+     }
+ 
+   /* Otherwise set up one address item with a null address, implying listening
+-  on all interfaces. */
++  on all interfaces. In an IPv6 world, we set up a second address for listening
++  on all IPv6 interfaces. Some IPv6 stacks will pick up incoming IPv4 calls on
++  an IPv6 wildcard socket, but some won't (there are security issues). Using
++  two sockets should work in all cases. We identify an IPv6 wildcard address by
++  the string ":". */
+ 
+   else
+     {
+@@ -698,6 +702,13 @@
+     addresses->next = NULL;
+     addresses->address[0] = 0;
+     listen_socket_count = 1;
++    #if HAVE_IPV6
++    addresses->next = store_get(sizeof(ip_address_item));
++    addresses->next->next = NULL;
++    addresses->next->address[0] = ':';
++    addresses->next->address[1] = 0;
++    listen_socket_count++;
++    #endif  /* HAVE_IPV6 */
+     }
+ 
+   /* Get a vector to remember all the sockets in */
+@@ -714,41 +725,20 @@
+   #endif
+ 
+   /* For each IP address, create a socket and bind it to the appropriate
+-  port. Note that if local_interfaces is not set, we bind a single socket to
+-  all interfaces. */
++  port. Some IPv6 stacks can handle IPv4 addresses on IPv6 sockets using
++  the mapping facilities. However, some don't do this because of security
++  concerns. Therefore, we use IPv4 sockets for IPv4 addresses even in an
++  IPv6 world. */
+ 
+   for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
+     {
+     int i;
++    int af = (strchr(ipa->address, ':') != NULL)? AF_INET6 : AF_INET;
+ 
+-    #if HAVE_IPV6
+-    BOOL ipv6_socket = TRUE;
+-    BOOL ipv6_address = strchr(ipa->address, ':') != NULL;
+-
+-    /* A system which has all the IPv6 libraries etc. may nevertheless not
+-    support IPv6 in the kernel, so if the socket creation fails, fall back
+-    on creating an IPv4 socket, except when we have an explicit IPv6 address,
+-    for which we really do need an IPv6 socket. */
+-
+-    listen_sockets[sk] = socket(AF_INET6, SOCK_STREAM, 0);
+-    if (listen_sockets[sk] < 0)
+-      {
+-      if (!ipv6_address)
+-        {
+-        listen_sockets[sk] = socket(AF_INET, SOCK_STREAM, 0);
+-        ipv6_socket = FALSE;
+-        }
+-      }
+-
+-    /* The IPv4 case */
+-
+-    #else    /* HAVE_IPV6 */
+-    listen_sockets[sk] = socket(AF_INET, SOCK_STREAM, 0);
+-    #endif   /* HAVE_IPV6 */
+-
++    listen_sockets[sk] = socket(af, SOCK_STREAM, 0);
+     if (listen_sockets[sk] < 0)
+-      log_write(0, LOG_PANIC_DIE, "socket creation failed: %s",
+-        strerror(errno));
++      log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
++        (af == AF_INET6)? '6' : '4', strerror(errno));
+ 
+     /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
+     is being handled.  Without this, a connection will prevent reuse of the
+@@ -765,44 +755,29 @@
+ 
+     memset(&sin, 0, sizeof(sin));
+ 
+-    /* This code has to be entirely different for IPv6 and IPv4 because
+-    of the different struct layouts. Sigh. Under IPv6, however, we may have
+-    ended up with an IPv4 socket because the kernel may not support IPv6 even
+-    if the libraries etc. are available. In this case, revert to IPv4 style
+-    code (this will happen only when the the address is not an IPv6 one).
+-    Although the code is identical, I've chosen to replicate it for ease of
+-    reading the two cases. */
++    /* Setup code when using an IPv6 socket. The wildcard address is ":", to
++    ensure an IPv6 socket is used. */
+ 
+     #if HAVE_IPV6
+-    if (ipv6_socket)
++    if (af == AF_INET6)
+       {
+       sin.v6.sin6_family = AF_INET6;
+       sin.v6.sin6_port = net_port;
+-
+-      if (ipa->address[0] == 0)
++      if (ipa->address[0] == ':' && ipa->address[1] == 0)
+         {
+         sin.v6.sin6_addr = anyaddr6;
+         DEBUG(9) debug_printf("listening on all interfaces (IPv6)\n");
+         }
+       else
+         {
+-        int rc;
+-        if (ipv6_address)
+-          rc = inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr);
+-        else
+-        /* We have an IPv6 socket, and an IPv4 address. We have to turn the
+-        address into an IPv6 mapped form. */
+-          {
+-          memmove(ipa->address+7, ipa->address, (int)strlen(ipa->address) + 1);
+-          memcpy(ipa->address, "::ffff:", 7);
+-          rc = inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr);
+-          }
+-        if (rc != 1)
++        if (inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr) != 1)
+           log_write(0, LOG_PANIC_DIE, "unable to parse \"%s\"", ipa->address);
+         DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+         }
+       }
+-    else   /* Revert to IPv4 code */
++    else
++    #endif  /* HAVE_IPV6 */
++    /* Setup code when using IPv4 socket. The wildcard address is "". */
+       {
+       sin.v4.sin_family = AF_INET;
+       sin.v4.sin_port = net_port;
+@@ -817,34 +792,25 @@
+         DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+         }
+       }
+-    #else   /* HAVE_IPV6 */
+ 
+-
+-    /* The IPv4 case is simple. */
+-
+-    sin.v4.sin_family = AF_INET;
+-    sin.v4.sin_port = net_port;
+-    if (ipa->address[0] == 0)
+-      {
+-      sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)INADDR_ANY;
+-      DEBUG(9) debug_printf("listening on all interfaces\n");
+-      }
+-    else
+-      {
+-      sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(ipa->address);
+-      DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+-      }
+-    #endif  /* HAVE_IPV6 */
+-
+-
+-    /* Retry loop */
++    /* Retry loop. Need to get the length of sin right for IPv4/IPv6
++    for some operating systems that check it. Although AF_INET6 is always
++    available (even on old IPv4 systems), the sin.v6 field isn't. */
  
      for (i = 9; i >= 0; i--)
        {
 -      if (bind(listen_sockets[sk], (struct sockaddr *)&sin, sizeof(sin)) < 0)
 +      if (bind(listen_sockets[sk], (struct sockaddr *)&sin,
-+               #ifdef HAVE_IPV6
-+               ipv6_socket? sizeof(sin.v6) : sizeof(sin.v4)
++               #if HAVE_IPV6
++               (af == AF_INET6)? sizeof(sin.v6) : sizeof(sin.v4)
 +               #else
 +               sizeof(sin)
-+               #endif
++               #endif /* HAVE_IPV6 */
 +           ) < 0)
          {
          char *msg = strerror(errno);
-         char *addr = (ipa->address[0] == 0)? "(any)" : ipa->address;
+-        char *addr = (ipa->address[0] == 0)? "(any)" : ipa->address;
++        char *addr = (ipa->address[0] == 0)? "(any IPv4)" :
++          (ipa->address[0] == ':' && ipa->address[1] == 0)? "(any IPv6)" :
++          ipa->address;
+         if (i == 0)
+           log_write(0, LOG_MAIN|LOG_PANIC_DIE,
+             "socket bind() to port %d for address %s failed: %s: "
diff --git a/mail/exim-old/files/patch-src::daemon.c b/mail/exim-old/files/patch-src::daemon.c
index b792bbf3529c..72ee5952dd6f 100644
--- a/mail/exim-old/files/patch-src::daemon.c
+++ b/mail/exim-old/files/patch-src::daemon.c
@@ -1,17 +1,189 @@
 --- src/daemon.c.orig	Tue Jul 10 11:52:32 2001
 +++ src/daemon.c	Tue Jul 10 11:53:33 2001
-@@ -841,7 +841,13 @@
+@@ -661,7 +661,7 @@
+   union sockaddr_46 sin;
+ 
+   #if HAVE_IPV6
+-  struct in6_addr anyaddr6 = IN6ADDR_ANY_INIT;
++  struct in6_addr anyaddr6 = in6addr_any;
+   #endif
+ 
+   /* Find the standard SMTP port if no port number given; otherwise
+@@ -690,7 +690,11 @@
+     }
+ 
+   /* Otherwise set up one address item with a null address, implying listening
+-  on all interfaces. */
++  on all interfaces. In an IPv6 world, we set up a second address for listening
++  on all IPv6 interfaces. Some IPv6 stacks will pick up incoming IPv4 calls on
++  an IPv6 wildcard socket, but some won't (there are security issues). Using
++  two sockets should work in all cases. We identify an IPv6 wildcard address by
++  the string ":". */
+ 
+   else
+     {
+@@ -698,6 +702,13 @@
+     addresses->next = NULL;
+     addresses->address[0] = 0;
+     listen_socket_count = 1;
++    #if HAVE_IPV6
++    addresses->next = store_get(sizeof(ip_address_item));
++    addresses->next->next = NULL;
++    addresses->next->address[0] = ':';
++    addresses->next->address[1] = 0;
++    listen_socket_count++;
++    #endif  /* HAVE_IPV6 */
+     }
+ 
+   /* Get a vector to remember all the sockets in */
+@@ -714,41 +725,20 @@
+   #endif
+ 
+   /* For each IP address, create a socket and bind it to the appropriate
+-  port. Note that if local_interfaces is not set, we bind a single socket to
+-  all interfaces. */
++  port. Some IPv6 stacks can handle IPv4 addresses on IPv6 sockets using
++  the mapping facilities. However, some don't do this because of security
++  concerns. Therefore, we use IPv4 sockets for IPv4 addresses even in an
++  IPv6 world. */
+ 
+   for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
+     {
+     int i;
++    int af = (strchr(ipa->address, ':') != NULL)? AF_INET6 : AF_INET;
+ 
+-    #if HAVE_IPV6
+-    BOOL ipv6_socket = TRUE;
+-    BOOL ipv6_address = strchr(ipa->address, ':') != NULL;
+-
+-    /* A system which has all the IPv6 libraries etc. may nevertheless not
+-    support IPv6 in the kernel, so if the socket creation fails, fall back
+-    on creating an IPv4 socket, except when we have an explicit IPv6 address,
+-    for which we really do need an IPv6 socket. */
+-
+-    listen_sockets[sk] = socket(AF_INET6, SOCK_STREAM, 0);
+-    if (listen_sockets[sk] < 0)
+-      {
+-      if (!ipv6_address)
+-        {
+-        listen_sockets[sk] = socket(AF_INET, SOCK_STREAM, 0);
+-        ipv6_socket = FALSE;
+-        }
+-      }
+-
+-    /* The IPv4 case */
+-
+-    #else    /* HAVE_IPV6 */
+-    listen_sockets[sk] = socket(AF_INET, SOCK_STREAM, 0);
+-    #endif   /* HAVE_IPV6 */
+-
++    listen_sockets[sk] = socket(af, SOCK_STREAM, 0);
+     if (listen_sockets[sk] < 0)
+-      log_write(0, LOG_PANIC_DIE, "socket creation failed: %s",
+-        strerror(errno));
++      log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
++        (af == AF_INET6)? '6' : '4', strerror(errno));
+ 
+     /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
+     is being handled.  Without this, a connection will prevent reuse of the
+@@ -765,44 +755,29 @@
+ 
+     memset(&sin, 0, sizeof(sin));
+ 
+-    /* This code has to be entirely different for IPv6 and IPv4 because
+-    of the different struct layouts. Sigh. Under IPv6, however, we may have
+-    ended up with an IPv4 socket because the kernel may not support IPv6 even
+-    if the libraries etc. are available. In this case, revert to IPv4 style
+-    code (this will happen only when the the address is not an IPv6 one).
+-    Although the code is identical, I've chosen to replicate it for ease of
+-    reading the two cases. */
++    /* Setup code when using an IPv6 socket. The wildcard address is ":", to
++    ensure an IPv6 socket is used. */
+ 
+     #if HAVE_IPV6
+-    if (ipv6_socket)
++    if (af == AF_INET6)
+       {
+       sin.v6.sin6_family = AF_INET6;
+       sin.v6.sin6_port = net_port;
+-
+-      if (ipa->address[0] == 0)
++      if (ipa->address[0] == ':' && ipa->address[1] == 0)
+         {
+         sin.v6.sin6_addr = anyaddr6;
+         DEBUG(9) debug_printf("listening on all interfaces (IPv6)\n");
+         }
+       else
+         {
+-        int rc;
+-        if (ipv6_address)
+-          rc = inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr);
+-        else
+-        /* We have an IPv6 socket, and an IPv4 address. We have to turn the
+-        address into an IPv6 mapped form. */
+-          {
+-          memmove(ipa->address+7, ipa->address, (int)strlen(ipa->address) + 1);
+-          memcpy(ipa->address, "::ffff:", 7);
+-          rc = inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr);
+-          }
+-        if (rc != 1)
++        if (inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr) != 1)
+           log_write(0, LOG_PANIC_DIE, "unable to parse \"%s\"", ipa->address);
+         DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+         }
+       }
+-    else   /* Revert to IPv4 code */
++    else
++    #endif  /* HAVE_IPV6 */
++    /* Setup code when using IPv4 socket. The wildcard address is "". */
+       {
+       sin.v4.sin_family = AF_INET;
+       sin.v4.sin_port = net_port;
+@@ -817,34 +792,25 @@
+         DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+         }
+       }
+-    #else   /* HAVE_IPV6 */
+ 
+-
+-    /* The IPv4 case is simple. */
+-
+-    sin.v4.sin_family = AF_INET;
+-    sin.v4.sin_port = net_port;
+-    if (ipa->address[0] == 0)
+-      {
+-      sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)INADDR_ANY;
+-      DEBUG(9) debug_printf("listening on all interfaces\n");
+-      }
+-    else
+-      {
+-      sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(ipa->address);
+-      DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+-      }
+-    #endif  /* HAVE_IPV6 */
+-
+-
+-    /* Retry loop */
++    /* Retry loop. Need to get the length of sin right for IPv4/IPv6
++    for some operating systems that check it. Although AF_INET6 is always
++    available (even on old IPv4 systems), the sin.v6 field isn't. */
  
      for (i = 9; i >= 0; i--)
        {
 -      if (bind(listen_sockets[sk], (struct sockaddr *)&sin, sizeof(sin)) < 0)
 +      if (bind(listen_sockets[sk], (struct sockaddr *)&sin,
-+               #ifdef HAVE_IPV6
-+               ipv6_socket? sizeof(sin.v6) : sizeof(sin.v4)
++               #if HAVE_IPV6
++               (af == AF_INET6)? sizeof(sin.v6) : sizeof(sin.v4)
 +               #else
 +               sizeof(sin)
-+               #endif
++               #endif /* HAVE_IPV6 */
 +           ) < 0)
          {
          char *msg = strerror(errno);
-         char *addr = (ipa->address[0] == 0)? "(any)" : ipa->address;
+-        char *addr = (ipa->address[0] == 0)? "(any)" : ipa->address;
++        char *addr = (ipa->address[0] == 0)? "(any IPv4)" :
++          (ipa->address[0] == ':' && ipa->address[1] == 0)? "(any IPv6)" :
++          ipa->address;
+         if (i == 0)
+           log_write(0, LOG_MAIN|LOG_PANIC_DIE,
+             "socket bind() to port %d for address %s failed: %s: "
diff --git a/mail/exim/files/patch-src::daemon.c b/mail/exim/files/patch-src::daemon.c
index b792bbf3529c..72ee5952dd6f 100644
--- a/mail/exim/files/patch-src::daemon.c
+++ b/mail/exim/files/patch-src::daemon.c
@@ -1,17 +1,189 @@
 --- src/daemon.c.orig	Tue Jul 10 11:52:32 2001
 +++ src/daemon.c	Tue Jul 10 11:53:33 2001
-@@ -841,7 +841,13 @@
+@@ -661,7 +661,7 @@
+   union sockaddr_46 sin;
+ 
+   #if HAVE_IPV6
+-  struct in6_addr anyaddr6 = IN6ADDR_ANY_INIT;
++  struct in6_addr anyaddr6 = in6addr_any;
+   #endif
+ 
+   /* Find the standard SMTP port if no port number given; otherwise
+@@ -690,7 +690,11 @@
+     }
+ 
+   /* Otherwise set up one address item with a null address, implying listening
+-  on all interfaces. */
++  on all interfaces. In an IPv6 world, we set up a second address for listening
++  on all IPv6 interfaces. Some IPv6 stacks will pick up incoming IPv4 calls on
++  an IPv6 wildcard socket, but some won't (there are security issues). Using
++  two sockets should work in all cases. We identify an IPv6 wildcard address by
++  the string ":". */
+ 
+   else
+     {
+@@ -698,6 +702,13 @@
+     addresses->next = NULL;
+     addresses->address[0] = 0;
+     listen_socket_count = 1;
++    #if HAVE_IPV6
++    addresses->next = store_get(sizeof(ip_address_item));
++    addresses->next->next = NULL;
++    addresses->next->address[0] = ':';
++    addresses->next->address[1] = 0;
++    listen_socket_count++;
++    #endif  /* HAVE_IPV6 */
+     }
+ 
+   /* Get a vector to remember all the sockets in */
+@@ -714,41 +725,20 @@
+   #endif
+ 
+   /* For each IP address, create a socket and bind it to the appropriate
+-  port. Note that if local_interfaces is not set, we bind a single socket to
+-  all interfaces. */
++  port. Some IPv6 stacks can handle IPv4 addresses on IPv6 sockets using
++  the mapping facilities. However, some don't do this because of security
++  concerns. Therefore, we use IPv4 sockets for IPv4 addresses even in an
++  IPv6 world. */
+ 
+   for (ipa = addresses, sk = 0; sk < listen_socket_count; ipa = ipa->next, sk++)
+     {
+     int i;
++    int af = (strchr(ipa->address, ':') != NULL)? AF_INET6 : AF_INET;
+ 
+-    #if HAVE_IPV6
+-    BOOL ipv6_socket = TRUE;
+-    BOOL ipv6_address = strchr(ipa->address, ':') != NULL;
+-
+-    /* A system which has all the IPv6 libraries etc. may nevertheless not
+-    support IPv6 in the kernel, so if the socket creation fails, fall back
+-    on creating an IPv4 socket, except when we have an explicit IPv6 address,
+-    for which we really do need an IPv6 socket. */
+-
+-    listen_sockets[sk] = socket(AF_INET6, SOCK_STREAM, 0);
+-    if (listen_sockets[sk] < 0)
+-      {
+-      if (!ipv6_address)
+-        {
+-        listen_sockets[sk] = socket(AF_INET, SOCK_STREAM, 0);
+-        ipv6_socket = FALSE;
+-        }
+-      }
+-
+-    /* The IPv4 case */
+-
+-    #else    /* HAVE_IPV6 */
+-    listen_sockets[sk] = socket(AF_INET, SOCK_STREAM, 0);
+-    #endif   /* HAVE_IPV6 */
+-
++    listen_sockets[sk] = socket(af, SOCK_STREAM, 0);
+     if (listen_sockets[sk] < 0)
+-      log_write(0, LOG_PANIC_DIE, "socket creation failed: %s",
+-        strerror(errno));
++      log_write(0, LOG_PANIC_DIE, "IPv%c socket creation failed: %s",
++        (af == AF_INET6)? '6' : '4', strerror(errno));
+ 
+     /* Set SO_REUSEADDR so that the daemon can be restarted while a connection
+     is being handled.  Without this, a connection will prevent reuse of the
+@@ -765,44 +755,29 @@
+ 
+     memset(&sin, 0, sizeof(sin));
+ 
+-    /* This code has to be entirely different for IPv6 and IPv4 because
+-    of the different struct layouts. Sigh. Under IPv6, however, we may have
+-    ended up with an IPv4 socket because the kernel may not support IPv6 even
+-    if the libraries etc. are available. In this case, revert to IPv4 style
+-    code (this will happen only when the the address is not an IPv6 one).
+-    Although the code is identical, I've chosen to replicate it for ease of
+-    reading the two cases. */
++    /* Setup code when using an IPv6 socket. The wildcard address is ":", to
++    ensure an IPv6 socket is used. */
+ 
+     #if HAVE_IPV6
+-    if (ipv6_socket)
++    if (af == AF_INET6)
+       {
+       sin.v6.sin6_family = AF_INET6;
+       sin.v6.sin6_port = net_port;
+-
+-      if (ipa->address[0] == 0)
++      if (ipa->address[0] == ':' && ipa->address[1] == 0)
+         {
+         sin.v6.sin6_addr = anyaddr6;
+         DEBUG(9) debug_printf("listening on all interfaces (IPv6)\n");
+         }
+       else
+         {
+-        int rc;
+-        if (ipv6_address)
+-          rc = inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr);
+-        else
+-        /* We have an IPv6 socket, and an IPv4 address. We have to turn the
+-        address into an IPv6 mapped form. */
+-          {
+-          memmove(ipa->address+7, ipa->address, (int)strlen(ipa->address) + 1);
+-          memcpy(ipa->address, "::ffff:", 7);
+-          rc = inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr);
+-          }
+-        if (rc != 1)
++        if (inet_pton(AF_INET6, ipa->address, &sin.v6.sin6_addr) != 1)
+           log_write(0, LOG_PANIC_DIE, "unable to parse \"%s\"", ipa->address);
+         DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+         }
+       }
+-    else   /* Revert to IPv4 code */
++    else
++    #endif  /* HAVE_IPV6 */
++    /* Setup code when using IPv4 socket. The wildcard address is "". */
+       {
+       sin.v4.sin_family = AF_INET;
+       sin.v4.sin_port = net_port;
+@@ -817,34 +792,25 @@
+         DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+         }
+       }
+-    #else   /* HAVE_IPV6 */
+ 
+-
+-    /* The IPv4 case is simple. */
+-
+-    sin.v4.sin_family = AF_INET;
+-    sin.v4.sin_port = net_port;
+-    if (ipa->address[0] == 0)
+-      {
+-      sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)INADDR_ANY;
+-      DEBUG(9) debug_printf("listening on all interfaces\n");
+-      }
+-    else
+-      {
+-      sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(ipa->address);
+-      DEBUG(9) debug_printf("listening on %s\n", ipa->address);
+-      }
+-    #endif  /* HAVE_IPV6 */
+-
+-
+-    /* Retry loop */
++    /* Retry loop. Need to get the length of sin right for IPv4/IPv6
++    for some operating systems that check it. Although AF_INET6 is always
++    available (even on old IPv4 systems), the sin.v6 field isn't. */
  
      for (i = 9; i >= 0; i--)
        {
 -      if (bind(listen_sockets[sk], (struct sockaddr *)&sin, sizeof(sin)) < 0)
 +      if (bind(listen_sockets[sk], (struct sockaddr *)&sin,
-+               #ifdef HAVE_IPV6
-+               ipv6_socket? sizeof(sin.v6) : sizeof(sin.v4)
++               #if HAVE_IPV6
++               (af == AF_INET6)? sizeof(sin.v6) : sizeof(sin.v4)
 +               #else
 +               sizeof(sin)
-+               #endif
++               #endif /* HAVE_IPV6 */
 +           ) < 0)
          {
          char *msg = strerror(errno);
-         char *addr = (ipa->address[0] == 0)? "(any)" : ipa->address;
+-        char *addr = (ipa->address[0] == 0)? "(any)" : ipa->address;
++        char *addr = (ipa->address[0] == 0)? "(any IPv4)" :
++          (ipa->address[0] == ':' && ipa->address[1] == 0)? "(any IPv6)" :
++          ipa->address;
+         if (i == 0)
+           log_write(0, LOG_MAIN|LOG_PANIC_DIE,
+             "socket bind() to port %d for address %s failed: %s: "