fd: Improve error handling of write_nonblock().
[paraslash.git] / dccp_send.c
index d2f81dd..fa2a163 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -13,7 +13,6 @@
 
 #include <regex.h>
 #include <sys/types.h>
-#include <dirent.h>
 #include <osl.h>
 
 #include "para.h"
 #include "server.h"
 #include "net.h"
 #include "list.h"
-#include "vss.h"
 #include "send.h"
+#include "sched.h"
+#include "vss.h"
 #include "fd.h"
 #include "close_on_fork.h"
 #include "chunk_queue.h"
 #include "server.cmdline.h"
 #include "acl.h"
 
-/** Do not write more than that many bytes at once. */
-#define DCCP_MAX_BYTES_PER_WRITE 1024
-
 static struct sender_status dccp_sender_status, *dss = &dccp_sender_status;
 
+struct dccp_fec_client {
+       struct fec_client_parms fcp;
+       struct fec_client *fc;
+};
+
 static void dccp_pre_select(int *max_fileno, fd_set *rfds,
                __a_unused fd_set *wfds)
 {
@@ -44,40 +46,106 @@ static void dccp_pre_select(int *max_fileno, fd_set *rfds,
                para_fd_set(dss->listen_fd, rfds, max_fileno);
 }
 
-static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
+/**
+ * Query the TX CCID used on the sender-client half connection.
+ * \param sockfd Server socket descriptor to query (after accept(2)).
+ * \return CCID number > 0, -1 on error/incompatibility.
+ *
+ * NB: This feature is only available on Linux > 2.6.30; on older kernels
+ * ENOPROTOOPT ("Protocol not available") will be returned.
+ */
+static int dccp_get_tx_ccid(int sockfd)
 {
-       struct sender_client *sc;
+       int tx_ccid;
+       socklen_t len = sizeof(tx_ccid);
+
+       if (getsockopt(sockfd, SOL_DCCP,
+                      DCCP_SOCKOPT_TX_CCID, &tx_ccid, &len) < 0) {
+               PARA_WARNING_LOG("DCCP_SOCKOPT_TX_CCID: %s\n", strerror(errno));
+               return -1;
+       }
+       return tx_ccid;
+}
 
-       if (dss->listen_fd < 0 || !FD_ISSET(dss->listen_fd, rfds))
-               return;
-       sc = accept_sender_client(dss);
-       if (!sc)
-               return;
-       /*
-        * Bypass unused CCID paths: the sender does not receive application data
-        * from the client; by shutting down this unused communication path we can
-        * reduce processing costs a bit. See analogous comment in dccp_recv.c.
-        */
-       if (shutdown(sc->fd, SHUT_RD) >= 0)
-               return;
-       PARA_WARNING_LOG("%s\n", strerror(errno));
+static void dccp_shutdown_client(struct sender_client *sc)
+{
+       struct dccp_fec_client *dfc = sc->private_data;
+
+       vss_del_fec_client(dfc->fc);
        shutdown_client(sc, dss);
 }
 
-static void dccp_send(long unsigned current_chunk,
-               __a_unused long unsigned chunks_sent, const char *buf,
-               size_t len, const char *header_buf, size_t header_len)
+static void dccp_shutdown_clients(void)
 {
        struct sender_client *sc, *tmp;
 
        list_for_each_entry_safe(sc, tmp, &dss->client_list, node)
-               send_chunk(sc, dss, DCCP_MAX_BYTES_PER_WRITE, current_chunk, buf,
-                       len, header_buf, header_len);
+               dccp_shutdown_client(sc);
 }
 
-static void dccp_shutdown_clients(void)
+/** * Obtain current MPS according to RFC 4340, sec. 14. */
+static int dccp_init_fec(struct sender_client *sc)
 {
-       shutdown_clients(dss);
+       int mps, ret;
+       socklen_t ml = sizeof(mps);
+
+       /* If call fails, return some sensible minimum value */
+       ret = getsockopt(sc->fd, SOL_DCCP, DCCP_SOCKOPT_GET_CUR_MPS, &mps, &ml);
+       if (ret < 0) {
+               PARA_NOTICE_LOG("can not determine MPS: %s\n", strerror(errno));
+               mps = generic_max_transport_msg_size(sc->fd) - DCCP_MAX_HEADER;
+       }
+       PARA_INFO_LOG("current MPS = %d bytes\n", mps);
+       assert(mps > 0);
+       if (conf.dccp_max_slice_size_arg > 0)
+               mps = PARA_MIN(mps, conf.dccp_max_slice_size_arg);
+       return mps;
+}
+
+static void dccp_send_fec(struct sender_client *sc, char *buf, size_t len)
+{
+       int ret = write_nonblock(sc->fd, buf, len);
+
+       if (ret < 0)
+               dccp_shutdown_client(sc);
+}
+
+static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
+{
+       struct sender_client *sc;
+       struct dccp_fec_client *dfc;
+       int tx_ccid;
+
+       sc = accept_sender_client(dss, rfds);
+       if (!sc)
+               return;
+
+       /* If CCID identifiable, present client as <host>#<port>~<ccid> */
+       tx_ccid = dccp_get_tx_ccid(sc->fd);
+       if (tx_ccid != -1) {
+               char *tmp = make_message("%s~%d", sc->name, tx_ccid);
+
+               free(sc->name);
+               sc->name = tmp;
+       }
+       /*
+        * Bypass unused CCID paths: the sender does not receive application data
+        * from the client; by shutting down this unused communication path we can
+        * reduce processing costs a bit. See analogous comment in dccp_recv.c.
+        */
+       if (shutdown(sc->fd, SHUT_RD) < 0) {
+               PARA_WARNING_LOG("%s\n", strerror(errno));
+               shutdown_client(sc, dss);
+               return;
+       }
+       dfc = para_calloc(sizeof(*dfc));
+       sc->private_data = dfc;
+       dfc->fcp.data_slices_per_group  = conf.dccp_data_slices_per_group_arg;
+       dfc->fcp.slices_per_group       = conf.dccp_slices_per_group_arg;
+       dfc->fcp.init_fec               = dccp_init_fec;
+       dfc->fcp.send_fec               = dccp_send_fec;
+       dfc->fcp.need_periodic_header   = false;
+       dfc->fc = vss_add_fec_client(sc, &dfc->fcp);
 }
 
 static int dccp_com_on(__a_unused struct sender_command_data *scd)
@@ -87,6 +155,7 @@ static int dccp_com_on(__a_unused struct sender_command_data *scd)
 
 static int dccp_com_off(__a_unused struct sender_command_data *scd)
 {
+       dccp_shutdown_clients();
        generic_com_off(dss);
        return 1;
 }
@@ -104,9 +173,34 @@ static int dccp_com_allow(struct sender_command_data *scd)
        return 1;
 }
 
+/**
+ * Return list of available CCIDs or warning, in static buffer.
+ */
+static const char *dccp_list_available_ccids(void)
+{
+       /* Worst case length: n * 3 digits + n-1 spaces + '\0' */
+       static char list[DCCP_MAX_HOST_CCIDS * 4];
+       uint8_t *ccids;
+       int i, len, nccids;
+
+       nccids = dccp_available_ccids(&ccids);
+       if (nccids < 0) {
+               snprintf(list, sizeof(list), "Unable to query available CCIDs");
+       } else {
+               for (i = len = 0; i < nccids; i++)
+                       len += snprintf(list + len, sizeof(list) - len,
+                                       "%s%d", i ? " " : "", ccids[i]);
+       }
+       return list;
+}
+
 static char *dccp_info(void)
 {
-       return get_sender_info(dss, "dccp");
+       char *info = get_sender_info(dss, "dccp");
+       char *ret  = make_message("%s" "\tsupported ccids: %s\n",
+                                 info, dccp_list_available_ccids());
+       free(info);
+       return ret;
 }
 
 /**
@@ -119,13 +213,14 @@ static char *dccp_info(void)
  */
 void dccp_send_init(struct sender *s)
 {
-       int ret;
+       int ret, k, n;
 
        s->info = dccp_info;
-       s->send = dccp_send;
+       s->send = NULL;
        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;
@@ -134,6 +229,15 @@ void dccp_send_init(struct sender *s)
        s->client_cmds[SENDER_ADD] = NULL;
        s->client_cmds[SENDER_DELETE] = NULL;
 
+       k = conf.dccp_data_slices_per_group_arg;
+       n = conf.dccp_slices_per_group_arg;
+
+       if (k <= 0 || n <= 0 || k >= n) {
+               PARA_WARNING_LOG("invalid FEC parameters, using defaults\n");
+               conf.dccp_data_slices_per_group_arg = 3;
+               conf.dccp_slices_per_group_arg = 4;
+       }
+
        init_sender_status(dss, conf.dccp_access_arg, conf.dccp_access_given,
                conf.dccp_port_arg, conf.dccp_max_clients_arg,
                conf.dccp_default_deny_given);