X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=src%2Fconnection.c;h=5f127eabb98f4f5db92cd343f1a0cdb592a0e2c8;hb=a50d5d492e9b63cec3f82a610f2bf0e1e470f9ae;hp=493d19deee9905a352880c8edfb3b4b4ed18176a;hpb=5debc3f1f692c1ebafc04fe5603ef51611ec10e5;p=pazpar2-moved-to-github.git

diff --git a/src/connection.c b/src/connection.c
index 493d19d..5f127ea 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -1,5 +1,5 @@
 /* This file is part of Pazpar2.
-   Copyright (C) 2006-2009 Index Data
+   Copyright (C) Index Data
 
 Pazpar2 is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free
@@ -42,11 +42,47 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #include <yaz/comstack.h>
 #include <yaz/tcpip.h>
 #include "connection.h"
-#include "pazpar2.h"
+#include "session.h"
 #include "host.h"
 #include "client.h"
 #include "settings.h"
 
+/* connection counting (1) , disable connection counting (0) */
+#if 1
+static YAZ_MUTEX g_mutex = 0;
+static int no_connections = 0;
+static int total_no_connections = 0;
+
+static int connection_use(int delta)
+{
+    int result;
+    if (!g_mutex)
+        yaz_mutex_create(&g_mutex);
+    yaz_mutex_enter(g_mutex);
+    no_connections += delta;
+    result = no_connections;
+    if (delta > 0)
+        total_no_connections += delta;
+    yaz_mutex_leave(g_mutex);
+    if (delta == 0)
+            return result;
+    yaz_log(YLOG_LOG, "%s connections=%d", delta > 0 ? "INC" : "DEC",
+            no_connections);
+    return result;
+}
+
+int connections_count(void)
+{
+    return connection_use(0);
+}
+
+
+#else
+#define connection_use(x)
+#define connections_count(x) 0
+#define connections_count_total(x) 0
+#endif
+
 
 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  */
@@ -55,22 +91,19 @@ struct connection {
     ZOOM_connection link;
     struct host *host;
     struct client *client;
-    char *ibuf;
-    int ibufsize;
     char *zproxy;
+    char *url;
     enum {
-        Conn_Resolving,
+        Conn_Closed,
         Conn_Connecting,
         Conn_Open
     } state;
-    int connect_timeout;
+    int operation_timeout;
     int session_timeout;
     struct connection *next; // next for same host or next in free list
 };
 
-static struct connection *connection_freelist = 0;
-
-static int connection_connect(struct connection *con);
+static int connection_connect(struct connection *con, iochan_man_t iochan_man);
 
 static int connection_is_idle(struct connection *co)
 {
@@ -83,7 +116,7 @@ static int connection_is_idle(struct connection *co)
     if (!ZOOM_connection_is_idle(link))
         return 0;
     event = ZOOM_connection_peek_event(link);
-    if (event == ZOOM_EVENT_NONE || event == ZOOM_EVENT_END)
+    if (event == ZOOM_EVENT_NONE)
         return 1;
     else
         return 0;
@@ -103,92 +136,109 @@ static void remove_connection_from_host(struct connection *con)
         if (*conp == con)
         {
             *conp = (*conp)->next;
-            return;
+            break;
         }
         conp = &(*conp)->next;
     }
-    assert(*conp == 0);
+    yaz_cond_broadcast(con->host->cond_ready);
 }
 
 // Close connection and recycle structure
-void connection_destroy(struct connection *co)
+static void connection_destroy(struct connection *co)
 {
     if (co->link)
     {
         ZOOM_connection_destroy(co->link);
         iochan_destroy(co->iochan);
     }
-    yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
+    yaz_log(YLOG_DEBUG, "%p Connection destroy %s", co, co->url);
 
-    remove_connection_from_host(co);
     if (co->client)
     {
         client_disconnect(co->client);
     }
+
     xfree(co->zproxy);
-    co->zproxy = 0;
-    co->next = connection_freelist;
-    connection_freelist = co;
+    xfree(co->url);
+    xfree(co);
+    connection_use(-1);
 }
 
-// Creates a new connection for client, associated with the host of 
+// Creates a new connection for client, associated with the host of
 // client's database
 static struct connection *connection_create(struct client *cl,
-                                            int connect_timeout,
-                                            int session_timeout)
+                                            const char *url,
+                                            struct host *host,
+                                            int operation_timeout,
+                                            int session_timeout,
+                                            iochan_man_t iochan_man)
 {
-    struct connection *new;
-    struct host *host = client_get_host(cl);
+    struct connection *co;
+
+    co = xmalloc(sizeof(*co));
+    co->host = host;
+
+    co->client = cl;
+    co->url = xstrdup(url);
+    co->zproxy = 0;
+    client_set_connection(cl, co);
+    co->link = 0;
+    co->state = Conn_Closed;
+    co->operation_timeout = operation_timeout;
+    co->session_timeout = session_timeout;
 
-    if ((new = connection_freelist))
-        connection_freelist = new->next;
-    else
-    {
-        new = xmalloc(sizeof (struct connection));
-        new->ibuf = 0;
-        new->ibufsize = 0;
-    }
-    new->host = host;
-    new->next = new->host->connections;
-    new->host->connections = new;
-    new->client = cl;
-    new->zproxy = 0;
-    client_set_connection(cl, new);
-    new->link = 0;
-    new->state = Conn_Resolving;
-    new->connect_timeout = connect_timeout;
-    new->session_timeout = session_timeout;
     if (host->ipport)
-        connection_connect(new);
-    return new;
+        connection_connect(co, iochan_man);
+
+    yaz_mutex_enter(host->mutex);
+    co->next = co->host->connections;
+    co->host->connections = co;
+    yaz_mutex_leave(host->mutex);
+
+    connection_use(1);
+    return co;
 }
 
 static void non_block_events(struct connection *co)
 {
-    struct client *cl = co->client;
+    int got_records = 0;
     IOCHAN iochan = co->iochan;
     ZOOM_connection link = co->link;
     while (1)
     {
+        struct client *cl = co->client;
         int ev;
         int r = ZOOM_event_nonblock(1, &link);
         if (!r)
             break;
+        if (!cl)
+            continue;
         ev = ZOOM_connection_last_event(link);
-#if 0
-        yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
+
+#if 1
+        yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 #endif
-        switch (ev) 
+        switch (ev)
         {
+        case ZOOM_EVENT_TIMEOUT:
+            break;
         case ZOOM_EVENT_END:
             {
                 const char *error, *addinfo;
-                if (ZOOM_connection_error(link, &error, &addinfo))
+                int err;
+                if ((err = ZOOM_connection_error(link, &error, &addinfo)))
                 {
                     yaz_log(YLOG_LOG, "Error %s from %s",
-                            error, client_get_url(cl));
+                            error, client_get_id(cl));
+                    client_set_diagnostic(cl, err, error, addinfo);
+                    client_set_state(cl, Client_Error);
+                }
+                else
+                {
+                    iochan_settimeout(iochan, co->session_timeout);
+                    client_set_state(cl, Client_Idle);
                 }
-                client_set_state(cl, Client_Idle);
+                yaz_cond_broadcast(co->host->cond_ready);
             }
             break;
         case ZOOM_EVENT_SEND_DATA:
@@ -199,115 +249,151 @@ static void non_block_events(struct connection *co)
             break;
         case ZOOM_EVENT_SEND_APDU:
             client_set_state(co->client, Client_Working);
+            iochan_settimeout(iochan, co->operation_timeout);
             break;
         case ZOOM_EVENT_RECV_APDU:
             break;
         case ZOOM_EVENT_CONNECT:
-            yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
+            yaz_log(YLOG_LOG, "Connected to %s", client_get_id(cl));
             co->state = Conn_Open;
-            iochan_settimeout(iochan, co->session_timeout);
             break;
         case ZOOM_EVENT_RECV_SEARCH:
             client_search_response(cl);
             break;
         case ZOOM_EVENT_RECV_RECORD:
-            client_record_response(cl);
+            client_record_response(cl, &got_records);
             break;
         default:
             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
-                    ev, client_get_url(cl));
+                    ev, client_get_id(cl));
+            break;
+        }
+    }
+    if (got_records)
+    {
+        struct client *cl = co->client;
+        if (cl)
+        {
+            client_check_preferred_watch(cl);
+            client_got_records(cl);
         }
     }
 }
 
 void connection_continue(struct connection *co)
 {
-    non_block_events(co);
+    int r = ZOOM_connection_exec_task(co->link);
+    if (!r)
+        non_block_events(co);
+    else
+    {
+        iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
+        iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
+    }
 }
 
 static void connection_handler(IOCHAN iochan, int event)
 {
     struct connection *co = iochan_getdata(iochan);
-    struct client *cl = co->client;
-    struct session *se = 0;
+    struct client *cl;
+    struct host *host = co->host;
 
-    if (cl)
-        se = client_get_session(cl);
-    else
+    yaz_mutex_enter(host->mutex);
+    cl = co->client;
+    if (!cl)
     {
+        /* no client associated with it.. We are probably getting
+           a closed connection from the target.. Or, perhaps, an unexpected
+           package.. We will just close the connection */
+        yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
+        remove_connection_from_host(co);
+        yaz_mutex_leave(host->mutex);
         connection_destroy(co);
-        return;
     }
-
-    if (event & EVENT_TIMEOUT)
+    else if (event & EVENT_TIMEOUT)
     {
-        if (co->state == Conn_Connecting)
-        {
-            yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
-            client_fatal(cl);
-        }
-        else
-        {
-            yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
-            connection_destroy(co);
-        }
+        ZOOM_connection_fire_event_timeout(co->link);
+        client_lock(cl);
+        non_block_events(co);
+        client_unlock(cl);
+
+        remove_connection_from_host(co);
+        yaz_mutex_leave(host->mutex);
+        connection_destroy(co);
     }
     else
     {
+        yaz_mutex_leave(host->mutex);
+
+        client_lock(cl);
         non_block_events(co);
 
         ZOOM_connection_fire_event_socket(co->link, event);
-        
+
         non_block_events(co);
+        client_unlock(cl);
+
+        if (co->link)
+        {
+            iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
+            iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
+        }
     }
 }
 
 
 // Disassociate connection from client
-void connection_release(struct connection *co)
+static void connection_release(struct connection *co)
 {
     struct client *cl = co->client;
 
-    yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
     if (!cl)
         return;
     client_set_connection(cl, 0);
     co->client = 0;
 }
 
-void connect_resolver_host(struct host *host)
+void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 {
-    struct connection *con = host->connections;
+    struct connection *con;
+
+    yaz_mutex_enter(host->mutex);
+    con = host->connections;
     while (con)
     {
-        if (con->state == Conn_Resolving)
+        if (con->state == Conn_Closed)
         {
-            if (!host->ipport) /* unresolved */
+            if (!host->ipport || !con->client) /* unresolved or no client */
             {
+                remove_connection_from_host(con);
+                yaz_mutex_leave(host->mutex);
                 connection_destroy(con);
-                /* start all over .. at some point it will be NULL */
-                con = host->connections;
-                continue;
-            }
-            else if (!con->client)
-            {
-                connection_destroy(con);
-                /* start all over .. at some point it will be NULL */
-                con = host->connections;
-                continue;
             }
             else
             {
-                connection_connect(con);
-                client_start_search(con->client);
+                struct session_database *sdb = client_get_database(con->client);
+                if (sdb)
+                {
+                    yaz_mutex_leave(host->mutex);
+                    client_start_search(con->client);
+                }
+                else
+                {
+                    remove_connection_from_host(con);
+                    yaz_mutex_leave(host->mutex);
+                    connection_destroy(con);
+                }
             }
+            /* start all over .. at some point it will be NULL */
+            yaz_mutex_enter(host->mutex);
+            con = host->connections;
         }
         else
         {
-            yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
+            con = con->next;
         }
-        con = con->next;
     }
+    yaz_mutex_leave(host->mutex);
 }
 
 static struct host *connection_get_host(struct connection *con)
@@ -315,148 +401,242 @@ static struct host *connection_get_host(struct connection *con)
     return con->host;
 }
 
-// Callback for use by event loop
-// We do this because ZOOM connections don't always have (the same) sockets
-static int socketfun(IOCHAN c)
+static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 {
-    struct connection *co = iochan_getdata(c);
-    if (!co->link)
-        return -1;
-    return ZOOM_connection_get_socket(co->link);
-}
-
-// Because ZOOM always knows what events it is interested in; we may not
-static int maskfun(IOCHAN c)
-{
-    struct connection *co = iochan_getdata(c);
-    if (!co->link)
-        return 0;
-
-    // This is cheating a little, and assuming that eventl mask IDs are always
-    // the same as ZOOM-C's.
-    return ZOOM_connection_get_mask(co->link);
-}
-
-static int connection_connect(struct connection *con)
-{
-    ZOOM_connection link = 0;
     struct host *host = connection_get_host(con);
     ZOOM_options zoptions = ZOOM_options_create();
     const char *auth;
+    const char *charset;
     const char *sru;
     const char *sru_version = 0;
-    char ipport[512] = "";
+    const char *value;
+    WRBUF w;
 
     struct session_database *sdb = client_get_database(con->client);
-    const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
+    const char *memcached = session_setting_oneval(sdb, PZ_MEMCACHED);
 
-    assert(host->ipport);
     assert(con);
 
     ZOOM_options_set(zoptions, "async", "1");
     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
-    if (zproxy && *zproxy)
+
+    if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
+        ZOOM_options_set(zoptions, "charset", charset);
+    if (memcached && *memcached)
+        ZOOM_options_set(zoptions, "memcached", memcached);
+
+    assert(host->ipport);
+    if (host->proxy)
+    {
+        yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
+        ZOOM_options_set(zoptions, "proxy", host->ipport);
+    }
+    else
     {
-        con->zproxy = xstrdup(zproxy);
-        ZOOM_options_set(zoptions, "proxy", zproxy);
+        assert(host->tproxy);
+        yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
+        ZOOM_options_set(zoptions, "tproxy", host->ipport);
     }
+
     if (apdulog && *apdulog)
         ZOOM_options_set(zoptions, "apdulog", apdulog);
 
-    if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
-        ZOOM_options_set(zoptions, "user", auth);
+
     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
         ZOOM_options_set(zoptions, "sru", sru);
-    if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION)) 
+    if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
         && *sru_version)
         ZOOM_options_set(zoptions, "sru_version", sru_version);
 
-    if (!(link = ZOOM_connection_create(zoptions)))
+    if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
+    {
+        /* allow splitting user and reset with a blank always */
+        const char *cp1 = strchr(auth, ' ');
+        if (!cp1 && sru && *sru)
+            cp1 =  strchr(auth, '/');
+        if (!cp1)
+        {
+            /* Z39.50 user/password style, or no password for SRU */
+            ZOOM_options_set(zoptions, "user", auth);
+        }
+        else
+        {
+            /* now consider group as well */
+            const char *cp2 = strchr(cp1 + 1, ' ');
+
+            ZOOM_options_setl(zoptions, "user", auth, cp1 - auth);
+            if (!cp2)
+                ZOOM_options_set(zoptions, "password", cp1 + 1);
+            else
+            {
+                ZOOM_options_setl(zoptions, "group", cp1 + 1, cp2 - cp1 - 1);
+                ZOOM_options_set(zoptions, "password", cp2 + 1);
+            }
+        }
+    }
+
+    value = session_setting_oneval(sdb, PZ_AUTHENTICATION_MODE);
+    if (value && *value)
+        ZOOM_options_set(zoptions, "authenticationMode", value);
+
+    if (!(con->link = ZOOM_connection_create(zoptions)))
     {
         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
         ZOOM_options_destroy(zoptions);
         return -1;
     }
 
-    if (sru && *sru)
-        strcpy(ipport, "http://");
-    strcat(ipport, host->ipport);
+    w = wrbuf_alloc();
+    if (sru && *sru && !strstr(con->url, "://"))
+        wrbuf_puts(w, "http://");
+    if (strchr(con->url, '#'))
+    {
+        const char *cp = strchr(con->url, '#');
+        wrbuf_write(w, con->url, cp - con->url);
+    }
+    else
+        wrbuf_puts(w, con->url);
+
+    ZOOM_connection_connect(con->link, wrbuf_cstr(w), 0);
 
-    ZOOM_connection_connect(link, ipport, 0);
-    
-    con->link = link;
-    con->iochan = iochan_create(0, connection_handler, 0);
+    con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
     con->state = Conn_Connecting;
-    iochan_settimeout(con->iochan, con->connect_timeout);
+    iochan_settimeout(con->iochan, con->operation_timeout);
     iochan_setdata(con->iochan, con);
-    iochan_setsocketfun(con->iochan, socketfun);
-    iochan_setmaskfun(con->iochan, maskfun);
-    pazpar2_add_channel(con->iochan);
+    iochan_add(iochan_man, con->iochan);
 
-    /* this fragment is bad DRY: from client_prep_connection */
     client_set_state(con->client, Client_Connecting);
     ZOOM_options_destroy(zoptions);
+    wrbuf_destroy(w);
     return 0;
 }
 
-const char *connection_get_url(struct connection *co)
-{
-    return client_get_url(co->client);
-}
-
 // Ensure that client has a connection associated
 int client_prep_connection(struct client *cl,
-                           int connect_timeout, int session_timeout)
+                           int operation_timeout, int session_timeout,
+                           iochan_man_t iochan_man,
+                           const struct timeval *abstime)
 {
     struct connection *co;
-    struct session *se = client_get_session(cl);
-    struct host *host = client_get_host(cl);
     struct session_database *sdb = client_get_database(cl);
     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
+    const char *url = session_setting_oneval(sdb, PZ_URL);
+    const char *sru = session_setting_oneval(sdb, PZ_SRU);
+    struct host *host = 0;
+    int default_port = *sru ? 80 : 210;
 
     if (zproxy && zproxy[0] == '\0')
         zproxy = 0;
 
+    if (!url || !*url)
+        url = sdb->database->id;
+
+    host = find_host(client_get_session(cl)->service->server->database_hosts,
+                     url, zproxy, default_port, iochan_man);
+
+    yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
+            client_get_id(cl), url);
     if (!host)
         return 0;
 
     co = client_get_connection(cl);
-
-    yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
-
+    if (co)
+    {
+        assert(co->host);
+        if (co->host == host && client_get_state(cl) == Client_Idle)
+        {
+            return 2;
+        }
+        connection_release(co);
+        co = 0;
+    }
     if (!co)
     {
+        int max_connections = 0;
+        int reuse_connections = 1;
+        const char *v = session_setting_oneval(client_get_database(cl),
+                                               PZ_MAX_CONNECTIONS);
+        if (v && *v)
+            max_connections = atoi(v);
+
+        v = session_setting_oneval(client_get_database(cl),
+                PZ_REUSE_CONNECTIONS);
+        if (v && *v)
+            reuse_connections = atoi(v);
+
         // See if someone else has an idle connection
         // We should look at timestamps here to select the longest-idle connection
-        for (co = host->connections; co; co = co->next)
-            if (connection_is_idle(co) &&
-                (!co->client || client_get_session(co->client) != se) &&
-                !strcmp(ZOOM_connection_option_get(co->link, "user"),
-                        session_setting_oneval(client_get_database(cl),
-                                               PZ_AUTHENTICATION)))
+        yaz_mutex_enter(host->mutex);
+        while (1)
+        {
+            int num_connections = 0;
+            for (co = host->connections; co; co = co->next)
+                num_connections++;
+            if (reuse_connections)
             {
-                if (zproxy == 0 && co->zproxy == 0)
-                    break;
-                if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
+                for (co = host->connections; co; co = co->next)
+                {
+                    if (connection_is_idle(co) &&
+                        !strcmp(url, co->url) &&
+                        (!co->client || client_get_state(co->client) == Client_Idle) &&
+                        !strcmp(ZOOM_connection_option_get(co->link, "user"),
+                                session_setting_oneval(client_get_database(cl),
+                                                       PZ_AUTHENTICATION)))
+                    {
+                        if (zproxy == 0 && co->zproxy == 0)
+                            break;
+                        if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
+                            break;
+                    }
+                }
+                if (co)
+                {
+                    yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
                     break;
+                }
             }
+            if (max_connections <= 0 || num_connections < max_connections)
+            {
+                yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
+                        num_connections, max_connections);
+                break;
+            }
+            yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
+                    num_connections, max_connections);
+            if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
+            {
+                yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
+                client_set_state(cl, Client_Error);
+                yaz_mutex_leave(host->mutex);
+                return 0;
+            }
+        }
         if (co)
         {
+            yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
             connection_release(co);
             client_set_connection(cl, co);
             co->client = cl;
+            /* ensure that connection is only assigned to this client
+               by marking the client non Idle */
+            client_set_state(cl, Client_Working);
+            yaz_mutex_leave(host->mutex);
+            co->operation_timeout = operation_timeout;
+            co->session_timeout = session_timeout;
             /* tells ZOOM to reconnect if necessary. Disabled becuase
                the ZOOM_connection_connect flushes the task queue */
-            co->connect_timeout = connect_timeout;
-            co->session_timeout = session_timeout;
             ZOOM_connection_connect(co->link, 0, 0);
         }
         else
         {
-            co = connection_create(cl, connect_timeout, session_timeout);
+            yaz_mutex_leave(host->mutex);
+            co = connection_create(cl, url, host,
+                                   operation_timeout, session_timeout,
+                                   iochan_man);
         }
+        assert(co->host);
     }
 
     if (co && co->link)