From: Gerrit Renker <grenker@cscs.ch>
Date: Thu, 25 Feb 2010 16:05:45 +0000 (+0100)
Subject: 06_get-tx-ccid.diff
X-Git-Tag: v0.4.2~39
X-Git-Url: http://git.tue.mpg.de/?a=commitdiff_plain;h=85d8b1b48ef832eaf485709f38cb443e5ecfbb7b;p=paraslash.git

06_get-tx-ccid.diff

This patch adds support for querying the TX half-connection CCID
in use to from sender to client.

On more recent kernels (> 2.6.30) supporting this functionality,
connected clients are now displayed in the manner
          <IP-address>"#"<port>"~"<CCID-number>
---

diff --git a/dccp_send.c b/dccp_send.c
index 94719f04..7d8967cc 100644
--- a/dccp_send.c
+++ b/dccp_send.c
@@ -44,15 +44,46 @@ static void dccp_pre_select(int *max_fileno, fd_set *rfds,
 		para_fd_set(dss->listen_fd, rfds, max_fileno);
 }
 
+/**
+ * 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)
+{
+	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;
+}
+
 static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
 {
 	struct sender_client *sc;
+	int tx_ccid;
 
 	if (dss->listen_fd < 0 || !FD_ISSET(dss->listen_fd, rfds))
 		return;
 	sc = accept_sender_client(dss);
 	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