Remove some unused error codes.
[paraslash.git] / udp_send.c
index 08429aa..adf2339 100644 (file)
 #include "close_on_fork.h"
 #include "chunk_queue.h"
 
+/**
+ * Time window during which ICMP Destination/Port Unreachable messages are
+ * ignored, covering transient receiver problems such as restarting the
+ * client, rebooting, reconfiguration, or handover.
+ */
+#define UDP_MAX_UNREACHABLE_TIME 30
+
 /** Describes one entry in the list of targets for the udp sender. */
 struct udp_target {
-       /** The hostname (DNS name or IPv4/v6 address string). */
-       char host[MAX_HOSTLEN];
-       /** The UDP port. */
-       int port;
+       /** Track time (seconds) of last ICMP Port Unreachable error */
+       time_t last_unreachable;
        /** Common sender client data */
        struct sender_client *sc;
        /** The opaque structure returned by vss_add_fec_client(). */
@@ -54,22 +59,20 @@ static void udp_close_target(struct sender_client *sc)
        if (sc->cq != NULL) {
                del_close_on_fork_list(sc->fd);
                cq_destroy(sc->cq);
-               free(sc->name);
-               sc->name = NULL;
                sc->cq = NULL;
-
        }
 }
 
-static void udp_delete_target(struct udp_target *ut, const char *msg)
+static void udp_delete_target(struct sender_client *sc, const char *msg)
 {
+       struct udp_target *ut = sc->private_data;
 
-       PARA_NOTICE_LOG("deleting %s#%d (%s) from list\n", ut->host,
-               ut->port, msg);
-       udp_close_target(ut->sc);
+       PARA_NOTICE_LOG("deleting %s (%s) from list\n", sc->name, msg);
+       udp_close_target(sc);
        vss_del_fec_client(ut->fc);
-       list_del(&ut->sc->node);
-       free(ut->sc);
+       list_del(&sc->node);
+       free(sc->name);
+       free(sc);
        free(ut);
 }
 
@@ -98,6 +101,7 @@ static int mcast_sender_setup(struct sender_client *sc)
 
        if (getpeername(sc->fd, (struct sockaddr *)&ss, &sslen) < 0)
                goto err;
+       assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
 
        /* RFC 3493, 5.2: -1 means 'use kernel default' */
        if (ttl < 0 || ttl > 255)
@@ -143,9 +147,6 @@ static int mcast_sender_setup(struct sender_client *sc)
                if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
                        break;
                return 0;
-       default:
-               PARA_ERROR_LOG("address family %d not supported", ss.ss_family);
-               return -E_ADDRESS_LOOKUP;
        }
 err:
        return -ERRNO_TO_PARA_ERROR(errno);
@@ -157,9 +158,8 @@ err:
 static void udp_init_session(struct sender_client *sc)
 {
        if (sc->cq == NULL) {
+               sc->cq = cq_new(UDP_CQ_BYTES);
                add_close_on_fork_list(sc->fd);
-               sc->cq   = cq_new(UDP_CQ_BYTES);
-               sc->name = para_strdup(remote_name(sc->fd));
                PARA_NOTICE_LOG("sending to udp %s\n", sc->name);
        }
 }
@@ -178,6 +178,28 @@ static void udp_shutdown_targets(void)
                }
 }
 
+static int udp_resolve_target(const char *url, struct sender_command_data *scd)
+{
+       const char *result;
+       int ret, port;
+
+       ret = parse_fec_url(url, scd);
+       if (ret)
+               return ret;
+       port = scd->port > 0 ? scd->port : conf.udp_default_port_arg;
+
+       ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
+       if (ret < 0)
+               return ret;
+
+       result = remote_name(ret);
+       close(ret);
+
+       if (!parse_url(result, scd->host, sizeof(scd->host), &scd->port))
+               return -E_ADDRESS_LOOKUP;
+       return 1;
+}
+
 static int udp_com_on(__a_unused struct sender_command_data *scd)
 {
        sender_status = SENDER_ON;
@@ -191,21 +213,35 @@ static int udp_com_off(__a_unused struct sender_command_data *scd)
        return 1;
 }
 
-static int udp_com_delete(struct sender_command_data *scd)
+static struct sender_client *udp_lookup_target(struct sender_command_data *scd)
 {
        struct sender_client *sc, *tmp;
+       char host[MAX_HOSTLEN];
+       int32_t port;
 
        list_for_each_entry_safe(sc, tmp, &targets, node) {
-               struct udp_target *ut = sc->private_data;
+               parse_url(sc->name, host, sizeof(host), &port);
 
                /* Unspecified port means wildcard port match */
-               if (scd->port > 0 && scd->port != ut->port)
+               if (scd->port > 0 && scd->port != port)
                        continue;
-               if (strcmp(ut->host, scd->host))
+               if (strcmp(host, scd->host))
                        continue;
-               udp_delete_target(ut, "com_delete");
+               return sc;
        }
-       return 1;
+       return NULL;
+}
+
+static int udp_com_delete(struct sender_command_data *scd)
+{
+       struct sender_client *sc = udp_lookup_target(scd);
+
+       if (sc) {
+               udp_delete_target(sc, "com_delete");
+               return 1;
+       }
+       PARA_NOTICE_LOG("not deleting non-existing target '%s'\n", scd->host);
+       return -E_TARGET_NOT_FOUND;
 }
 
 /** Initialize UDP session and set maximum payload size. */
@@ -219,28 +255,66 @@ static int udp_init_fec(struct sender_client *sc)
        return mps;
 }
 
-static int udp_send_fec(struct sender_client *sc, char *buf, size_t len)
+/** Check and clear socket error if any. */
+static int udp_check_socket_state(struct sender_client *sc)
 {
        struct udp_target *ut = sc->private_data;
        int ret;
+       socklen_t errlen = sizeof(ret);
+
+       if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
+               PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
+               return 0;
+       } else if (ret == 0) {
+               return 0;
+       } else if (ret == ECONNREFUSED) {
+               time_t dist = now->tv_sec - ut->last_unreachable;
+
+               if (dist <= UDP_MAX_UNREACHABLE_TIME) {
+                       return 0;
+               } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
+                       ut->last_unreachable = now->tv_sec;
+                       return 0;
+               } else {
+                       /*
+                        * unreachable_time < dist <= 2 * unreachable_time
+                        * No errors are allowed during this time window.
+                        */
+                       PARA_NOTICE_LOG("Evicting %s after %d seconds "
+                                       "of connection errors.\n",
+                                       sc->name, (int)dist);
+               }
+       }
+       return -ERRNO_TO_PARA_ERROR(ret);
+}
+
+static int udp_send_fec(struct sender_client *sc, char *buf, size_t len)
+{
+       int ret;
 
        if (sender_status == SENDER_OFF)
                return 0;
+       if (len == 0 && !cq_peek(sc->cq))
+               return 0;
+       ret = udp_check_socket_state(sc);
+       if (ret < 0)
+               goto fail;
        ret = send_queued_chunks(sc->fd, sc->cq);
-       if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED))
-               ret = 0;
        if (ret < 0)
                goto fail;
-       if (!len)
-               return 0;
        if (!ret) { /* still data left in the queue */
                ret = cq_force_enqueue(sc->cq, buf, len);
                assert(ret >= 0);
                return 0;
        }
        ret = write_nonblock(sc->fd, buf, len);
-       if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED))
+       if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
+               /*
+                * Happens if meanwhile an ICMP Destination / Port Unreachable
+                * has arrived. Ignore, persistent errors will be caught above.
+                */
                ret = 0;
+       }
        if (ret < 0)
                goto fail;
        if (ret != len) {
@@ -249,55 +323,55 @@ static int udp_send_fec(struct sender_client *sc, char *buf, size_t len)
        }
        return 1;
 fail:
-       udp_delete_target(ut, para_strerror(-ret));
+       udp_delete_target(sc, para_strerror(-ret));
        return ret;
 }
 
-static void udp_add_target(struct sender_command_data *scd)
+static int udp_com_add(struct sender_command_data *scd)
 {
-       int ret, port = scd->port > 0 ? scd->port : conf.udp_default_port_arg;
-       struct udp_target *ut = para_calloc(sizeof(*ut));
-
-       strncpy(ut->host, scd->host, sizeof(ut->host));
-       ut->port = scd->port > 0 ? scd->port : conf.udp_default_port_arg;
+       int ret;
+       struct udp_target *ut;
+       struct sender_client *sc = udp_lookup_target(scd);
 
+       if (sc) {
+               PARA_NOTICE_LOG("target %s already exists - not adding it\n",
+                               sc->name);
+               return -E_TARGET_EXISTS;
+       }
+       ut = para_calloc(sizeof(*ut));
+       sc = ut->sc = para_calloc(sizeof(*sc));
        ut->fcp.slices_per_group      = scd->slices_per_group;
        ut->fcp.data_slices_per_group = scd->data_slices_per_group;
        ut->fcp.max_slice_bytes       = scd->max_slice_bytes;
        ut->fcp.init_fec              = udp_init_fec;
        ut->fcp.send_fec              = udp_send_fec;
 
-       ut->sc = para_calloc(sizeof(*ut->sc));
-       ut->sc->private_data = ut;
-       ut->sc->fd = -1;
-       ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
+       sc->private_data = ut;
+       sc->fd = -1;
+       ret = para_connect_simple(IPPROTO_UDP, scd->host, scd->port);
        if (ret < 0)
                goto err;
-       ut->sc->fd = ret;
+       sc->fd = ret;
 
-       ret = mcast_sender_setup(ut->sc);
+       ret = mcast_sender_setup(sc);
        if (ret < 0)
                goto err;
-       ret = mark_fd_nonblocking(ut->sc->fd);
+       ret = mark_fd_nonblocking(sc->fd);
        if (ret < 0)
                goto err;
-       PARA_INFO_LOG("adding to target list (%s#%d)\n", ut->host, ut->port);
-       ut->fc = vss_add_fec_client(ut->sc, &ut->fcp);
-       para_list_add(&ut->sc->node, &targets);
-       return;
+       sc->name = para_strdup(remote_name(sc->fd));
+       PARA_INFO_LOG("adding to target list (%s)\n", sc->name);
+       ut->fc = vss_add_fec_client(sc, &ut->fcp);
+       para_list_add(&sc->node, &targets);
+       return 1;
 err:
-       if (ut->sc->fd >= 0)
-               close(ut->sc->fd);
-       PARA_NOTICE_LOG("failed to set up %s#%d (%s)- not adding it\n",
-               scd->host, port, para_strerror(-ret));
-       free(ut->sc);
+       if (sc->fd >= 0)
+               close(sc->fd);
+       PARA_NOTICE_LOG("failed to set up %s:%d (%s)- not adding it\n",
+                       scd->host, scd->port, para_strerror(-ret));
+       free(sc);
        free(ut);
-}
-
-static int udp_com_add(struct sender_command_data *scd)
-{
-       udp_add_target(scd);
-       return 1;
+       return ret;
 }
 
 static char *udp_info(void)
@@ -307,10 +381,8 @@ static char *udp_info(void)
 
        list_for_each_entry(sc, &targets, node) {
                struct udp_target *ut = sc->private_data;
-               bool is_v6 = strchr(ut->host, ':') != NULL;
-               char *tmp = make_message("%s%s%s%s:%d/%u:%u:%u ", tgts ? : "",
-                       is_v6 ? "[" : "", ut->host,
-                       is_v6 ? "]" : "", ut->port,
+               char *tmp = make_message("%s%s/%u:%u:%u ",
+                       tgts ? : "", sc->name,
                        ut->fcp.max_slice_bytes,
                        ut->fcp.data_slices_per_group,
                        ut->fcp.slices_per_group
@@ -338,12 +410,11 @@ static void udp_init_target_list(void)
 
        INIT_LIST_HEAD(&targets);
        for (i = 0; i < conf.udp_target_given; i++) {
-               if (parse_fec_url(conf.udp_target_arg[i], &scd) < 0) {
-                       PARA_CRIT_LOG("syntax error for udp target option "
-                               "#%d, ignoring\n", i);
-                       continue;
-               }
-               udp_add_target(&scd);
+               if (udp_resolve_target(conf.udp_target_arg[i], &scd) < 0)
+                       PARA_CRIT_LOG("not adding requested target '%s'\n",
+                                       conf.udp_target_arg[i]);
+               else
+                       udp_com_add(&scd);
        }
 }
 
@@ -351,15 +422,17 @@ static char *udp_help(void)
 {
        return make_message(
                "usage: {on|off}\n"
-               "usage: {add|delete} host[:port][/packet_size:k:n]\n"
+               "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
+               "       - k is the number of data slices per FEC group\n"
+               "       - n is the total number of slices in a FEC group\n"
+               "       - packet_size reduces the slice size below path MTU\n\n"
                "examples: add 224.0.1.38:1500  (IPv4 multicast)\n"
-               "          add 224.0.1.38:1500/1400:14:16\n"
-               "              (likewise, using 1400 byte packets, with 14\n"
-               "               data slices per 16 slice FEC group)\n"
+               "          add 224.0.1.38:8080/14:16 (explicit FEC)\n"
                "          add 10.10.1.42       (using default port)\n"
                "          add [FF05::42]:1500  (IPv6 multicast)\n"
                "          add [::1]            (IPv6 localhost/default port)\n"
                "          delete myhost.net    (host with port wildcard)\n"
+               "          delete 10.1.2.3:456  (IPv4 with explicit port)\n"
                "          delete [badc0de::1]  (IPv6 with port wildcard)\n"
        );
 }
@@ -380,6 +453,7 @@ void udp_send_init(struct sender *s)
        s->pre_select = NULL;
        s->post_select = NULL;
        s->shutdown_clients = udp_shutdown_targets;
+       s->resolve_target = udp_resolve_target;
        s->client_cmds[SENDER_ON] = udp_com_on;
        s->client_cmds[SENDER_OFF] = udp_com_off;
        s->client_cmds[SENDER_DENY] = NULL;