]> git.tuebingen.mpg.de Git - paraslash.git/commitdiff
Merge branch 't/udp_lookup'
authorAndre Noll <maan@systemlinux.org>
Mon, 28 Jun 2010 11:19:21 +0000 (13:19 +0200)
committerAndre Noll <maan@systemlinux.org>
Mon, 28 Jun 2010 11:19:21 +0000 (13:19 +0200)
command.c
dccp_send.c
error.h
http_send.c
net.c
send.h
send_common.c
udp_recv.c
udp_send.c

index 42fa3e7584e7f622b7137730edcbfb5f07cbfd0f..bcbbc3406def48eba64adeb31eecd81997f634b2 100644 (file)
--- a/command.c
+++ b/command.c
@@ -191,10 +191,10 @@ static int check_sender_args(int argc, char * const * argv, struct sender_comman
 int com_sender(struct rc4_context *rc4c, int argc, char * const * argv)
 {
        int i, ret;
+       char *msg = NULL;
        struct sender_command_data scd;
 
        if (argc < 2) {
-               char *msg = NULL;
                for (i = 0; senders[i].name; i++) {
                        char *tmp = make_message("%s%s\n",
                                msg? msg : "", senders[i].name);
@@ -207,7 +207,6 @@ int com_sender(struct rc4_context *rc4c, int argc, char * const * argv)
        }
        ret = check_sender_args(argc, argv, &scd);
        if (ret < 0) {
-               char *msg;
                if (scd.sender_num < 0)
                        return ret;
                msg = senders[scd.sender_num].help();
@@ -215,6 +214,16 @@ int com_sender(struct rc4_context *rc4c, int argc, char * const * argv)
                free(msg);
                return ret;
        }
+
+       switch (scd.cmd_num) {
+       case SENDER_ADD:
+       case SENDER_DELETE:
+               assert(senders[scd.sender_num].resolve_target);
+               ret = senders[scd.sender_num].resolve_target(argv[3], &scd);
+               if (ret < 0)
+                       return ret;
+       }
+
        for (i = 0; i < 10; i++) {
                mutex_lock(mmd_mutex);
                if (mmd->sender_cmd_data.cmd_num >= 0) {
index 6cfdfbbeddccb42cd46a5d4b8c06aec24a0427ec..41aaf234da6ce89da2e25ce30871405f663cac38 100644 (file)
@@ -219,6 +219,7 @@ void dccp_send_init(struct sender *s)
        s->pre_select = dccp_pre_select;
        s->post_select = dccp_post_select;
        s->shutdown_clients = dccp_shutdown_clients;
+       s->resolve_target = NULL;
        s->help = generic_sender_help;
        s->client_cmds[SENDER_ON] = dccp_com_on;
        s->client_cmds[SENDER_OFF] = dccp_com_off;
diff --git a/error.h b/error.h
index 31903062ab7be0f30d2939cb088d9da45989dd85..94a44854cfdb961c136dcca35fb6850f27a33e89 100644 (file)
--- a/error.h
+++ b/error.h
@@ -16,7 +16,6 @@ DEFINE_ERRLIST_OBJECT_ENUM;
 #define TIME_ERRORS
 #define CLOSE_ON_FORK_ERRORS
 #define DAEMON_ERRORS
-#define UDP_SEND_ERRORS
 #define GUI_ERRORS
 #define RINGBUFFER_ERRORS
 #define SCORE_ERRORS
@@ -223,7 +222,7 @@ extern const char **para_errlist[];
 
 #define NET_ERRORS \
        PARA_ERROR(NAME_TOO_LONG, "name too long for struct sockaddr_un"), \
-       PARA_ERROR(ADDRESS_LOOKUP, "address lookup / socket creation failed"), \
+       PARA_ERROR(ADDRESS_LOOKUP, "can not resolve requested address"),\
        PARA_ERROR(CHMOD, "failed to set socket mode"), \
        PARA_ERROR(SENDMSG, "sendmsg() failed"), \
        PARA_ERROR(RECVMSG, "recvmsg() failed"), \
@@ -235,6 +234,11 @@ extern const char **para_errlist[];
        PARA_ERROR(UDP_OVERRUN, "output buffer overrun"), \
 
 
+#define UDP_SEND_ERRORS \
+       PARA_ERROR(TARGET_EXISTS, "requested target is already present"),\
+       PARA_ERROR(TARGET_NOT_FOUND, "requested target not found")
+
+
 #define HTTP_RECV_ERRORS \
        PARA_ERROR(HTTP_RECV_OVERRUN, "http_recv: output buffer overrun"), \
 
index e8b22cf9958959b48d3d84855aeaf45cb1a5cf62..e376c4646cc92554dda73cd906d34f9d2f8e7155 100644 (file)
@@ -251,6 +251,7 @@ void http_send_init(struct sender *s)
        s->pre_select = http_pre_select;
        s->post_select = http_post_select;
        s->shutdown_clients = http_shutdown_clients;
+       s->resolve_target = NULL;
        s->help = generic_sender_help;
        s->client_cmds[SENDER_ON] = http_com_on;
        s->client_cmds[SENDER_OFF] = http_com_off;
diff --git a/net.c b/net.c
index fa9575a6e5a6aa7d857777e1ea85d5f52ec05c01..be637ec7a5e24e7d1856ed21370139d7a05c5a2c 100644 (file)
--- a/net.c
+++ b/net.c
@@ -598,25 +598,28 @@ int generic_max_transport_msg_size(int sockfd)
  *
  * \param sa The IPv4/IPv6 socket address to use.
  *
+ * \return Host string in numeric host:port format, \sa parse_url().
  * \sa getnameinfo(3), services(5), nsswitch.conf(5)
  */
 static char *host_and_port(const struct sockaddr_storage *ss)
 {
        const struct sockaddr *sa = normalize_ip_address(ss);
        char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
-       static char output[sizeof(hbuf) + sizeof(sbuf) + 2];
+       static char output[sizeof(hbuf) + sizeof(sbuf) + 4];
        int ret;
 
        ret = getnameinfo(sa, salen(sa),
                          hbuf, sizeof(hbuf),
                          sbuf, sizeof(sbuf),
-                         NI_NUMERICHOST);
-       if (ret == 0) {
-               snprintf(output, sizeof(output), "%s#%s", hbuf, sbuf);
-       } else {
+                         NI_NUMERICHOST | NI_NUMERICSERV);
+       if (ret) {
                snprintf(output, sizeof(output), "(unknown)");
                PARA_WARNING_LOG("hostname lookup error (%s).\n",
                                 gai_strerror(ret));
+       } else if (sa->sa_family == AF_INET6) {
+               snprintf(output, sizeof(output), "[%s]:%s", hbuf, sbuf);
+       } else {
+               snprintf(output, sizeof(output), "%s:%s", hbuf, sbuf);
        }
        return output;
 }
diff --git a/send.h b/send.h
index df0cd1cb0612c1f3e52078e1d3478423566c8152..5f874521ce281e1801ab3d3682619bb872e33d13 100644 (file)
--- a/send.h
+++ b/send.h
@@ -87,6 +87,15 @@ struct sender {
         * pointer means this command is not implemented by this sender.
         */
        int (*client_cmds[NUM_SENDER_CMDS])(struct sender_command_data*);
+       /**
+        * Resolve target-specific URL string
+        *
+        * This method must be defined if the sender supports the add/delete
+        * subcommands. It interprets a string specifying a target URL in a
+        * sender-specific fashion (e.g. embedded FEC string). It can also
+        * fill in sender-specific defaults if necessary.
+        */
+       int (*resolve_target)(const char *, struct sender_command_data *);
 };
 
 /** Describes one client, connected to a paraslash sender. */
index dea96081d43a51209a0d667cbf8f73a9ff11e08d..005583cf52bf425f67727df68600c1094a3c0ad8 100644 (file)
@@ -309,7 +309,7 @@ struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfd
        ss->num_clients++;
        sc = para_calloc(sizeof(*sc));
        sc->fd = fd;
-       sc->name = make_message("%s", remote_name(fd));
+       sc->name = para_strdup(remote_name(fd));
        sc->cq = cq_new(MAX_CQ_BYTES);
        para_list_add(&sc->node, &ss->client_list);
        add_close_on_fork_list(fd);
@@ -341,47 +341,51 @@ char *generic_sender_help(void)
 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
 {
        int32_t val;
-       char *a = para_strdup(arg), *b = a, *e = strchr(b, ':');
+       char *a = para_strdup(arg),
+            *b = strchr(a, ':'),
+            *c = strrchr(a, ':');
        int ret = -E_COMMAND_SYNTAX;
 
-       /* parse max slice bytes */
-       if (!e)
+       if (!b || !c)
                goto out;
-       *e = '\0';
-       ret = para_atoi32(b, &val);
-       if (ret < 0)
-               goto out;
-       ret = -ERRNO_TO_PARA_ERROR(EINVAL);
-       if (val < 0 || val > 65535)
-               goto out;
-       scd->max_slice_bytes = val;
-       /* parse data_slices_per_group */
-       b = e + 1;
-       e = strchr(b, ':');
-       ret = -E_COMMAND_SYNTAX;
-       if (!e)
-               goto out;
-       *e = '\0';
-       ret = para_atoi32(b, &val);
+       *b = *c = '\0';
+
+       ret = para_atoi32(a, &val);
        if (ret < 0)
                goto out;
-       ret = -ERRNO_TO_PARA_ERROR(EINVAL);
+
+       /* optional max_slice_bytes (0 means "use MTU") */
+       if (b == c) {
+               scd->max_slice_bytes = 0;
+       } else {
+               if (val < 0 || val > 65535)
+                       goto fec_einval;
+               scd->max_slice_bytes = val;
+
+               ret = para_atoi32(b + 1, &val);
+               if (ret < 0)
+                       goto out;
+       }
+
+       /* k = data_slices_per_group */
        if (val < 0 || val > 255)
-               goto out;
+               goto fec_einval;
        scd->data_slices_per_group = val;
-       /* parse slices_per_group */
-       b = e + 1;
-       ret = para_atoi32(b, &val);
+
+       /* n = slices_per_group */
+       ret = para_atoi32(c + 1, &val);
        if (ret < 0)
                goto out;
-       ret = -ERRNO_TO_PARA_ERROR(EINVAL);
        if (val < 0 || val < scd->data_slices_per_group)
-               goto out;
+               goto fec_einval;
        scd->slices_per_group = val;
        ret = 0;
 out:
        free(a);
        return ret;
+fec_einval:
+       ret = -ERRNO_TO_PARA_ERROR(EINVAL);
+       goto out;
 }
 
 /**
@@ -401,26 +405,22 @@ out:
  */
 int parse_fec_url(const char *arg, struct sender_command_data *scd)
 {
-       int ret;
-       ssize_t len = sizeof(scd->host);
        char *a = para_strdup(arg), *p = strchr(a, '/');
+       int ret = 0;
+
+       /* default fec parameters */
+       scd->max_slice_bytes       = 0;
+       scd->data_slices_per_group = 14;
+       scd->slices_per_group      = 16;
 
        if (p) {
                *p = '\0';
-               len = strlen(a);
-       }
-       ret = -ERRNO_TO_PARA_ERROR(EINVAL);
-       if (!parse_url(a, scd->host, len, &scd->port))
-               goto out;
-       if (p) {
                ret = parse_fec_parms(p + 1, scd);
-               goto out;
+               if (ret < 0)
+                       goto out;
        }
-       /* use default fec parameters. */
-       scd->max_slice_bytes = 0;
-       scd->slices_per_group = 16;
-       scd->data_slices_per_group = 14;
-       ret = 0;
+       if (!parse_url(a, scd->host, sizeof(scd->host), &scd->port))
+               ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 out:
        free(a);
        return ret;
index 5520c6fb65b29f9d12575b211cb990dd53e7d8d3..8e2fcf2fde3fbb5ed94ac06816b2acd8f25f2ffb 100644 (file)
@@ -142,6 +142,7 @@ static int mcast_receiver_setup(int fd, const char *iface)
 
        if (getsockname(fd, (struct sockaddr *)&ss, &sslen) < 0)
                goto err;
+       assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
 
        if (iface != NULL && id == 0)
                PARA_WARNING_LOG("could not resolve interface %s, using default", iface);
@@ -179,9 +180,6 @@ static int mcast_receiver_setup(int fd, const char *iface)
                                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);
index 24ebf5848ed3c2de5d671de98dab142ce9018581..adf233979c31e2aff79ecdf94b5b16fd6f8765da 100644 (file)
 
 /** 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 */
@@ -63,22 +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);
 }
 
@@ -107,6 +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)
@@ -152,9 +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);
@@ -166,9 +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);
        }
 }
@@ -187,6 +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;
@@ -200,21 +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. */
@@ -229,12 +256,13 @@ static int udp_init_fec(struct sender_client *sc)
 }
 
 /** Check and clear socket error if any. */
-static int udp_check_socket_state(struct udp_target *ut)
+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(ut->sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
+       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) {
@@ -252,9 +280,9 @@ static int udp_check_socket_state(struct udp_target *ut)
                         * unreachable_time < dist <= 2 * unreachable_time
                         * No errors are allowed during this time window.
                         */
-                       PARA_NOTICE_LOG("Evicting %s#%d after %d seconds "
+                       PARA_NOTICE_LOG("Evicting %s after %d seconds "
                                        "of connection errors.\n",
-                                       ut->host, ut->port, (int)dist);
+                                       sc->name, (int)dist);
                }
        }
        return -ERRNO_TO_PARA_ERROR(ret);
@@ -262,14 +290,13 @@ static int udp_check_socket_state(struct udp_target *ut)
 
 static int udp_send_fec(struct sender_client *sc, char *buf, size_t len)
 {
-       struct udp_target *ut = sc->private_data;
        int ret;
 
        if (sender_status == SENDER_OFF)
                return 0;
-       if (len == 0 && !cq_peek(ut->sc->cq))
+       if (len == 0 && !cq_peek(sc->cq))
                return 0;
-       ret = udp_check_socket_state(ut);
+       ret = udp_check_socket_state(sc);
        if (ret < 0)
                goto fail;
        ret = send_queued_chunks(sc->fd, sc->cq);
@@ -296,55 +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)
@@ -354,10 +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
@@ -385,12 +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);
        }
 }
 
@@ -398,15 +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"
        );
 }
@@ -427,6 +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;