MINOR: tcp: When binding socket, attempt to reuse one from the old proc.

Try to reuse any socket from the old process, provided by the "-x" flag,
before binding a new one, assuming it is compatible.
"Compatible" here means same address and port, same namspace if any,
same interface if any, and that the following flags are the same :
LI_O_FOREIGN, LI_O_V6ONLY and LI_O_V4V6.
Also change tcp_bind_listener() to always enable/disable socket options,
instead of just doing so if it is in the configuration file, as the option
may have been removed, ie TCP_FASTOPEN may have been set in the old process,
and removed from the new configuration, so we have to disable it.

diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 5e12b9990ef5ad720c5c80fee963e21fc4688a42..57d6fc1fa54595137203a30ebce29940c651d8b3 100644 (file)
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -110,6 +110,12 @@ static struct protocol proto_tcpv6 = {
        .nb_listeners = 0,
 };
 
+/* Default TCP parameters, got by opening a temporary TCP socket. */
+#ifdef TCP_MAXSEG
+static int default_tcp_maxseg = -1;
+static int default_tcp6_maxseg = -1;
+#endif
+
 /* Binds ipv4/ipv6 address <local> to socket <fd>, unless <flags> is set, in which
  * case we try to bind <remote>. <flags> is a 2-bit field consisting of :
  *  - 0 : ignore remote address (may even be a NULL pointer)
@@ -731,6 +737,83 @@ int tcp_connect_probe(struct connection *conn)
        return 0;
 }
 
+/* XXX: Should probably be elsewhere */
+static int compare_sockaddr(struct sockaddr_storage *a, struct sockaddr_storage *b)
+{
+       if (a->ss_family != b->ss_family) {
+               return (-1);
+       }
+       switch (a->ss_family) {
+       case AF_INET:
+               {
+                       struct sockaddr_in *a4 = (void *)a, *b4 = (void *)b;
+                       if (a4->sin_port != b4->sin_port)
+                               return (-1);
+                       return (memcmp(&a4->sin_addr, &b4->sin_addr,
+                           sizeof(a4->sin_addr)));
+               }
+       case AF_INET6:
+               {
+                       struct sockaddr_in6 *a6 = (void *)a, *b6 = (void *)b;
+                       if (a6->sin6_port != b6->sin6_port)
+                               return (-1);
+                       return (memcmp(&a6->sin6_addr, &b6->sin6_addr,
+                           sizeof(a6->sin6_addr)));
+               }
+       default:
+               return (-1);
+       }
+
+}
+
+#define LI_MANDATORY_FLAGS     (LI_O_FOREIGN | LI_O_V6ONLY | LI_O_V4V6)
+/* When binding the listeners, check if a socket has been sent to us by the
+ * previous process that we could reuse, instead of creating a new one.
+ */
+static int tcp_find_compatible_fd(struct listener *l)
+{
+       struct xfer_sock_list *xfer_sock = xfer_sock_list;
+       int ret = -1;
+
+       while (xfer_sock) {
+               if (!compare_sockaddr(&xfer_sock->addr, &l->addr)) {
+                       if ((l->interface == NULL && xfer_sock->iface == NULL) ||
+                           (l->interface != NULL && xfer_sock->iface != NULL &&
+                            !strcmp(l->interface, xfer_sock->iface))) {
+                               if ((l->options & LI_MANDATORY_FLAGS) ==
+                                   (xfer_sock->options & LI_MANDATORY_FLAGS)) {
+                                       if ((xfer_sock->namespace == NULL &&
+                                           l->netns == NULL)
+#ifdef CONFIG_HAP_NS
+                                           || (xfer_sock->namespace != NULL &&
+                                           l->netns != NULL &&
+                                           !strcmp(xfer_sock->namespace,
+                                           l->netns->node.key))
+#endif
+                                          ) {
+                                               break;
+                                       }
+
+                               }
+                       }
+               }
+               xfer_sock = xfer_sock->next;
+       }
+       if (xfer_sock != NULL) {
+               ret = xfer_sock->fd;
+               if (xfer_sock == xfer_sock_list)
+                       xfer_sock_list = xfer_sock->next;
+               if (xfer_sock->prev)
+                       xfer_sock->prev->next = xfer_sock->next;
+               if (xfer_sock->next)
+                       xfer_sock->next->prev = xfer_sock->prev;
+               free(xfer_sock->iface);
+               free(xfer_sock->namespace);
+               free(xfer_sock);
+       }
+       return ret;
+}
+#undef L1_MANDATORY_FLAGS
 
 /* This function tries to bind a TCPv4/v6 listener. It may return a warning or
  * an error message in <errmsg> if the message is at most <errlen> bytes long
@@ -752,6 +835,36 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
        int ext, ready;
        socklen_t ready_len;
        const char *msg = NULL;
+#ifdef TCP_MAXSEG
+
+       /* Create a temporary TCP socket to get default parameters we can't
+        * guess.
+        * */
+       ready_len = sizeof(default_tcp_maxseg);
+       if (default_tcp_maxseg == -1) {
+               default_tcp_maxseg = -2;
+               fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+               if (fd < 0)
+                       Warning("Failed to create a temporary socket!\n");
+               else {
+                       if (getsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &default_tcp_maxseg,
+                           &ready_len) == -1)
+                               Warning("Failed to get the default value of TCP_MAXSEG\n");
+               }
+               close(fd);
+       }
+       if (default_tcp6_maxseg == -1) {
+               default_tcp6_maxseg = -2;
+               fd = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
+               if (fd >= 0) {
+                       if (getsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &default_tcp6_maxseg,
+                           &ready_len) == -1)
+                               Warning("Failed ot get the default value of TCP_MAXSEG for IPv6\n");
+                       close(fd);
+               }
+       }
+#endif
+
 
        /* ensure we never return garbage */
        if (errlen)
@@ -762,6 +875,9 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
 
        err = ERR_NONE;
 
+       if (listener->fd == -1)
+               listener->fd = tcp_find_compatible_fd(listener);
+
        /* if the listener already has an fd assigned, then we were offered the
         * fd by an external process (most likely the parent), and we don't want
         * to create a new socket. However we still want to set a few flags on
@@ -800,6 +916,17 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
 
        if (listener->options & LI_O_NOLINGER)
                setsockopt(fd, SOL_SOCKET, SO_LINGER, &nolinger, sizeof(struct linger));
+       else {
+               struct linger tmplinger;
+               socklen_t len = sizeof(tmplinger);
+               if (getsockopt(fd, SOL_SOCKET, SO_LINGER, &tmplinger, &len) == 0 &&
+                   (tmplinger.l_onoff == 1 || tmplinger.l_linger == 0)) {
+                       tmplinger.l_onoff = 0;
+                       tmplinger.l_linger = 0;
+                       setsockopt(fd, SOL_SOCKET, SO_LINGER, &tmplinger,
+                           sizeof(tmplinger));
+               }
+       }
 
 #ifdef SO_REUSEPORT
        /* OpenBSD and Linux 3.9 support this. As it's present in old libc versions of
@@ -869,6 +996,23 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
                        msg = "cannot set MSS";
                        err |= ERR_WARN;
                }
+       } else if (ext) {
+               int tmpmaxseg = -1;
+               int defaultmss;
+               socklen_t len = sizeof(tmpmaxseg);
+
+               if (listener->addr.ss_family == AF_INET)
+                       defaultmss = default_tcp_maxseg;
+               else
+                       defaultmss = default_tcp6_maxseg;
+
+               getsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &tmpmaxseg, &len);
+               if (tmpmaxseg != defaultmss && setsockopt(fd, IPPROTO_TCP,
+                                               TCP_MAXSEG, &defaultmss,
+                                               sizeof(defaultmss)) == -1) {
+                       msg = "cannot set MSS";
+                       err |= ERR_WARN;
+               }
        }
 #endif
 #if defined(TCP_USER_TIMEOUT)
@@ -878,7 +1022,9 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
                        msg = "cannot set TCP User Timeout";
                        err |= ERR_WARN;
                }
-       }
+       } else
+               setsockopt(fd, IPPROTO_TCP, TCP_USER_TIMEOUT, &zero,
+                   sizeof(zero));
 #endif
 #if defined(TCP_DEFER_ACCEPT)
        if (listener->options & LI_O_DEF_ACCEPT) {
@@ -888,7 +1034,9 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
                        msg = "cannot enable DEFER_ACCEPT";
                        err |= ERR_WARN;
                }
-       }
+       } else
+               setsockopt(fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &zero,
+                   sizeof(zero));
 #endif
 #if defined(TCP_FASTOPEN)
        if (listener->options & LI_O_TCP_FO) {
@@ -898,6 +1046,21 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
                        msg = "cannot enable TCP_FASTOPEN";
                        err |= ERR_WARN;
                }
+       } else {
+               socklen_t len;
+               int qlen;
+               len = sizeof(qlen);
+               /* Only disable fast open if it was enabled, we don't want
+                * the kernel to create a fast open queue if there's none.
+                */
+               if (getsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &qlen, &len) == 0 &&
+                   qlen != 0) {
+                       if (setsockopt(fd, IPPROTO_TCP, TCP_FASTOPEN, &zero,
+                           sizeof(zero)) == -1) {
+                               msg = "cannot disable TCP_FASTOPEN";
+                               err |= ERR_WARN;
+                       }
+               }
        }
 #endif
 #if defined(IPV6_V6ONLY)
@@ -928,6 +1091,8 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
 #if defined(TCP_QUICKACK)
        if (listener->options & LI_O_NOQUICKACK)
                setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, &zero, sizeof(zero));
+       else
+               setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, &one, sizeof(one));
 #endif
 
        /* the socket is ready */