9 files changed, 232 insertions, 24 deletions

diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index c45daabd3bfe..74563b38ffd9 100644
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -1,7 +1,6 @@
 DCCP protocol
 ============
 
-Last updated: 10 November 2005
 
 Contents
 ========
@@ -42,8 +41,11 @@ Socket options
 DCCP_SOCKOPT_PACKET_SIZE is used for CCID3 to set default packet size for
 calculations.
 
-DCCP_SOCKOPT_SERVICE sets the service. This is compulsory as per the
-specification. If you don't set it you will get EPROTO.
+DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of
+service codes (RFC 4340, sec. 8.1.2); if this socket option is not set,
+the socket will fall back to 0 (which means that no meaningful service code
+is present). Connecting sockets set at most one service option; for
+listening sockets, multiple service codes can be specified.
 
 Notes
 =====
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 2d7671c92c0b..d6f4ec467a4b 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -169,6 +169,12 @@ enum {
         DCCPO_MAX_CCID_SPECIFIC = 255,
 };
 
+/* DCCP CCIDS */
+enum {
+        DCCPC_CCID2 = 2,
+        DCCPC_CCID3 = 3,
+};
+
 /* DCCP features */
 enum {
         DCCPF_RESERVED = 0,
@@ -320,7 +326,7 @@ static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
 /* initial values for each feature */
 #define DCCPF_INITIAL_SEQUENCE_WINDOW           100
 #define DCCPF_INITIAL_ACK_RATIO                 2
-#define DCCPF_INITIAL_CCID                      2
+#define DCCPF_INITIAL_CCID                      DCCPC_CCID2
 #define DCCPF_INITIAL_SEND_ACK_VECTOR           1
 /* FIXME: for now we're default to 1 but it should really be 0 */
 #define DCCPF_INITIAL_SEND_NDP_COUNT            1
@@ -404,6 +410,7 @@ struct dccp_service_list {
 };
 
 #define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1)
+#define DCCP_SERVICE_CODE_IS_ABSENT              0
 
 static inline int dccp_list_has_service(const struct dccp_service_list *sl,
                                         const __be32 service)
@@ -484,11 +491,6 @@ static inline struct dccp_minisock *dccp_msk(const struct sock *sk)
         return (struct dccp_minisock *)&dccp_sk(sk)->dccps_minisock;
 }
 
-static inline int dccp_service_not_initialized(const struct sock *sk)
-{
-        return dccp_sk(sk)->dccps_service == DCCP_SERVICE_INVALID_VALUE;
-}
-
 static inline const char *dccp_role(const struct sock *sk)
 {
         switch (dccp_sk(sk)->dccps_role) {
diff --git a/net/dccp/Kconfig b/net/dccp/Kconfig
index 859e3359fcda..e2a095d0fd80 100644
--- a/net/dccp/Kconfig
+++ b/net/dccp/Kconfig
@@ -40,6 +40,22 @@ config IP_DCCP_DEBUG
 
           Just say N.
 
+config NET_DCCPPROBE
+        tristate "DCCP connection probing"
+        depends on PROC_FS && KPROBES
+        ---help---
+        This module allows for capturing the changes to DCCP connection
+        state in response to incoming packets. It is used for debugging
+        DCCP congestion avoidance modules. If you don't understand
+        what was just said, you don't need it: say N.
+
+        Documentation on how to use the packet generator can be found
+        at http://linux-net.osdl.org/index.php/DccpProbe
+
+        To compile this code as a module, choose M here: the
+        module will be called dccp_probe.
+
+
 endmenu
 
 endmenu
diff --git a/net/dccp/Makefile b/net/dccp/Makefile
index 7696e219b05d..17ed99c46617 100644
--- a/net/dccp/Makefile
+++ b/net/dccp/Makefile
@@ -11,9 +11,11 @@ dccp_ipv4-y := ipv4.o
 dccp-$(CONFIG_IP_DCCP_ACKVEC) += ackvec.o
 
 obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o
+obj-$(CONFIG_NET_DCCPPROBE) += dccp_probe.o
 
 dccp-$(CONFIG_SYSCTL) += sysctl.o
 
 dccp_diag-y := diag.o
+dccp_probe-y := probe.o
 
 obj-y += ccids/
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 457dd3db7f41..2efb505aeb35 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -808,7 +808,7 @@ static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 }
 
 static struct ccid_operations ccid2 = {
-        .ccid_id                = 2,
+        .ccid_id                = DCCPC_CCID2,
         .ccid_name              = "ccid2",
         .ccid_owner             = THIS_MODULE,
         .ccid_hc_tx_obj_size    = sizeof(struct ccid2_hc_tx_sock),
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 195aa9566228..67d2dc0e7c67 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -1240,7 +1240,7 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
 }
 
 static struct ccid_operations ccid3 = {
-        .ccid_id                   = 3,
+        .ccid_id                   = DCCPC_CCID3,
         .ccid_name                 = "ccid3",
         .ccid_owner                = THIS_MODULE,
         .ccid_hc_tx_obj_size       = sizeof(struct ccid3_hc_tx_sock),
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 9a1a76a7dc41..66be29b6f508 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -56,9 +56,6 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 
         dp->dccps_role = DCCP_ROLE_CLIENT;
 
-        if (dccp_service_not_initialized(sk))
-                return -EPROTO;
-
         if (addr_len < sizeof(struct sockaddr_in))
                 return -EINVAL;
 
diff --git a/net/dccp/probe.c b/net/dccp/probe.c
new file mode 100644
index 000000000000..146496fce2e2
--- /dev/null
+++ b/net/dccp/probe.c
@@ -0,0 +1,198 @@
+/*
+ * dccp_probe - Observe the DCCP flow with kprobes.
+ *
+ * The idea for this came from Werner Almesberger's umlsim
+ * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
+ *
+ * Modified for DCCP from Stephen Hemminger's code
+ * Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *
+ * This program 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 Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/socket.h>
+#include <linux/dccp.h>
+#include <linux/proc_fs.h>
+#include <linux/module.h>
+#include <linux/kfifo.h>
+#include <linux/vmalloc.h>
+
+#include "dccp.h"
+#include "ccid.h"
+#include "ccids/ccid3.h"
+
+static int port;
+
+static int bufsize = 64 * 1024;
+
+static const char procname[] = "dccpprobe";
+
+struct {
+        struct kfifo      *fifo;
+        spinlock_t        lock;
+        wait_queue_head_t wait;
+        struct timeval    tstart;
+} dccpw;
+
+static void printl(const char *fmt, ...)
+{
+        va_list args;
+        int len;
+        struct timeval now;
+        char tbuf[256];
+
+        va_start(args, fmt);
+        do_gettimeofday(&now);
+
+        now.tv_sec -= dccpw.tstart.tv_sec;
+        now.tv_usec -= dccpw.tstart.tv_usec;
+        if (now.tv_usec < 0) {
+                --now.tv_sec;
+                now.tv_usec += 1000000;
+        }
+
+        len = sprintf(tbuf, "%lu.%06lu ",
+                      (unsigned long) now.tv_sec,
+                      (unsigned long) now.tv_usec);
+        len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
+        va_end(args);
+
+        kfifo_put(dccpw.fifo, tbuf, len);
+        wake_up(&dccpw.wait);
+}
+
+static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
+                         struct msghdr *msg, size_t size)
+{
+        const struct dccp_minisock *dmsk = dccp_msk(sk);
+        const struct inet_sock *inet = inet_sk(sk);
+        const struct ccid3_hc_tx_sock *hctx;
+
+        if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
+                hctx = ccid3_hc_tx_sk(sk);
+        else
+                hctx = NULL;
+
+        if (port == 0 || ntohs(inet->dport) == port ||
+            ntohs(inet->sport) == port) {
+                if (hctx)
+                        printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %d\n",
+                           NIPQUAD(inet->saddr), ntohs(inet->sport),
+                           NIPQUAD(inet->daddr), ntohs(inet->dport), size,
+                           hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
+                           hctx->ccid3hctx_p, hctx->ccid3hctx_t_ipi);
+                else
+                        printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
+                           NIPQUAD(inet->saddr), ntohs(inet->sport),
+                           NIPQUAD(inet->daddr), ntohs(inet->dport), size);
+        }
+
+        jprobe_return();
+        return 0;
+}
+
+static struct jprobe dccp_send_probe = {
+        .kp     = { .addr = (kprobe_opcode_t *)&dccp_sendmsg, },
+        .entry  = (kprobe_opcode_t *)&jdccp_sendmsg,
+};
+
+static int dccpprobe_open(struct inode *inode, struct file *file)
+{
+        kfifo_reset(dccpw.fifo);
+        do_gettimeofday(&dccpw.tstart);
+        return 0;
+}
+
+static ssize_t dccpprobe_read(struct file *file, char __user *buf,
+                              size_t len, loff_t *ppos)
+{
+        int error = 0, cnt = 0;
+        unsigned char *tbuf;
+
+        if (!buf || len < 0)
+                return -EINVAL;
+
+        if (len == 0)
+                return 0;
+
+        tbuf = vmalloc(len);
+        if (!tbuf)
+                return -ENOMEM;
+
+        error = wait_event_interruptible(dccpw.wait,
+                                         __kfifo_len(dccpw.fifo) != 0);
+        if (error)
+                goto out_free;
+
+        cnt = kfifo_get(dccpw.fifo, tbuf, len);
+        error = copy_to_user(buf, tbuf, cnt);
+
+out_free:
+        vfree(tbuf);
+
+        return error ? error : cnt;
+}
+
+static struct file_operations dccpprobe_fops = {
+        .owner   = THIS_MODULE,
+        .open    = dccpprobe_open,
+        .read    = dccpprobe_read,
+};
+
+static __init int dccpprobe_init(void)
+{
+        int ret = -ENOMEM;
+
+        init_waitqueue_head(&dccpw.wait);
+        spin_lock_init(&dccpw.lock);
+        dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
+
+        if (!proc_net_fops_create(procname, S_IRUSR, &dccpprobe_fops))
+                goto err0;
+
+        ret = register_jprobe(&dccp_send_probe);
+        if (ret)
+                goto err1;
+
+        pr_info("DCCP watch registered (port=%d)\n", port);
+        return 0;
+err1:
+        proc_net_remove(procname);
+err0:
+        kfifo_free(dccpw.fifo);
+        return ret;
+}
+module_init(dccpprobe_init);
+
+static __exit void dccpprobe_exit(void)
+{
+        kfifo_free(dccpw.fifo);
+        proc_net_remove(procname);
+        unregister_jprobe(&dccp_send_probe);
+
+}
+module_exit(dccpprobe_exit);
+
+MODULE_PARM_DESC(port, "Port to match (0=all)");
+module_param(port, int, 0);
+
+MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
+module_param(bufsize, int, 0);
+
+MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
+MODULE_DESCRIPTION("DCCP snooper");
+MODULE_LICENSE("GPL");
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 962df0ea31aa..72cbdcfc2c65 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -217,7 +217,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
         icsk->icsk_sync_mss     = dccp_sync_mss;
         dp->dccps_mss_cache     = 536;
         dp->dccps_role          = DCCP_ROLE_UNDEFINED;
-        dp->dccps_service       = DCCP_SERVICE_INVALID_VALUE;
+        dp->dccps_service       = DCCP_SERVICE_CODE_IS_ABSENT;
         dp->dccps_l_ack_ratio   = dp->dccps_r_ack_ratio = 1;
 
         return 0;
@@ -267,12 +267,6 @@ static inline int dccp_listen_start(struct sock *sk)
         struct dccp_sock *dp = dccp_sk(sk);
 
         dp->dccps_role = DCCP_ROLE_LISTEN;
-        /*
-         * Apps need to use setsockopt(DCCP_SOCKOPT_SERVICE)
-         * before calling listen()
-         */
-        if (dccp_service_not_initialized(sk))
-                return -EPROTO;
         return inet_csk_listen_start(sk, TCP_SYNQ_HSIZE);
 }
 
@@ -540,9 +534,6 @@ static int dccp_getsockopt_service(struct sock *sk, int len,
         int err = -ENOENT, slen = 0, total_len = sizeof(u32);
 
         lock_sock(sk);
-        if (dccp_service_not_initialized(sk))
-                goto out;
-
         if ((sl = dp->dccps_service_list) != NULL) {
                 slen = sl->dccpsl_nr * sizeof(u32);
                 total_len += slen;