Since node internal messages are passed directly to socket it is not
possible to observe
this message exchange via tcpdump or wireshark.
We now remedy this by making it possible to clone such messages and send the
clones to the
loopback interface. The clones are dropped at reception and have no
functional role except
making the traffic visible.
The feature is turned on/off by enabling/disabling the loopback "bearer"
"eth:lo".
Signed-off-by: John Rutherford <john.rutherf...@dektech.com.au>
Signed-off-by: Jon Maloy <jon.ma...@ericsson.com>
---
net/tipc/bcast.c | 5 +++-
net/tipc/bearer.c | 67
++++++++++++++++++++++++++++++++++++++++++++++++++++++
net/tipc/bearer.h | 3 +++
net/tipc/core.c | 5 +++-
net/tipc/core.h | 9 ++++++++
net/tipc/netlink.c | 2 +-
net/tipc/node.c | 2 ++
net/tipc/topsrv.c | 3 +++
8 files changed, 93 insertions(+), 3 deletions(-)
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 6c997d4..db40129 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -406,8 +406,11 @@ int tipc_mcast_xmit(struct net *net, struct
sk_buff_head *pkts,
rc = tipc_bcast_xmit(net,
pkts, cong_link_cnt);
}
- if (dests->local)
+ if (dests->local) {
+ if (unlikely(tipc_loopback_trace(net)))
+ tipc_clone_to_loopback(net,
&localq);
tipc_sk_mcast_rcv(net, &localq, &inputq);
+ }
exit:
/* This queue should normally be empty by now */
__skb_queue_purge(pkts);
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 2bed658..27b4fd7 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -836,6 +836,12 @@ int __tipc_nl_bearer_disable(struct sk_buff *skb,
struct genl_info *info)
name = nla_data(attrs[TIPC_NLA_BEARER_NAME]);
+ if (!strcmp(name, "eth:lo")) {
+ tipc_net(net)->loopback_trace = false;
+ pr_info("Disabled packet tracing on loopback
interface\n");
+ return 0;
+ }
+
bearer = tipc_bearer_find(net, name);
if (!bearer)
return -EINVAL;
@@ -881,6 +887,12 @@ int __tipc_nl_bearer_enable(struct sk_buff *skb, struct
genl_info *info)
bearer = nla_data(attrs[TIPC_NLA_BEARER_NAME]);
+ if (!strcmp(bearer, "eth:lo")) {
+ tipc_net(net)->loopback_trace = true;
+ pr_info("Enabled packet tracing on loopback
interface\n");
+ return 0;
+ }
+
if (attrs[TIPC_NLA_BEARER_DOMAIN])
domain =
nla_get_u32(attrs[TIPC_NLA_BEARER_DOMAIN]);
@@ -1021,6 +1033,61 @@ int tipc_nl_bearer_set(struct sk_buff *skb, struct
genl_info *info)
return err;
}
+void tipc_clone_to_loopback(struct net *net, struct sk_buff_head *xmitq)
+{
+ struct net_device *dev = net->loopback_dev;
+ struct sk_buff *skb, *_skb;
+ int exp;
+
+ skb_queue_walk(xmitq, _skb) {
+ skb = pskb_copy(_skb, GFP_ATOMIC);
+ if (!skb)
+ continue;
+ exp = SKB_DATA_ALIGN(dev->hard_header_len -
skb_headroom(skb));
+ if (exp > 0 && pskb_expand_head(skb, exp, 0,
GFP_ATOMIC)) {
+ kfree_skb(skb);
+ continue;
+ }
+ skb_reset_network_header(skb);
+ skb->dev = dev;
+ skb->protocol = htons(ETH_P_TIPC);
+ dev_hard_header(skb, dev, ETH_P_TIPC,
dev->dev_addr,
+ dev->dev_addr,
skb->len);
+ dev_queue_xmit(skb);
+ }
+}
+
+static int tipc_loopback_rcv_pkt(struct sk_buff *skb, struct net_device
*dev,
+ struct
packet_type *pt, struct net_device *od)
+{
+ consume_skb(skb);
+ return NET_RX_SUCCESS;
+}
+
+int tipc_attach_loopback(struct net *net)
+{
+ struct net_device *dev = net->loopback_dev;
+ struct tipc_net *tn = tipc_net(net);
+
+ if (!dev)
+ return -ENODEV;
+ dev_hold(dev);
+ tn->loopback_pt.dev = dev;
+ tn->loopback_pt.type = htons(ETH_P_TIPC);
+ tn->loopback_pt.func = tipc_loopback_rcv_pkt;
+ tn->loopback_trace = false;
+ dev_add_pack(&tn->loopback_pt);
+ return 0;
+}
+
+void tipc_detach_loopback(struct net *net)
+{
+ struct tipc_net *tn = tipc_net(net);
+
+ dev_remove_pack(&tn->loopback_pt);
+ dev_put(net->loopback_dev);
+}
+
static int __tipc_nl_add_media(struct tipc_nl_msg *msg,
struct tipc_media
*media, int nlflags)
{
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 7f4c569..ef7fad9 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -232,6 +232,9 @@ void tipc_bearer_xmit(struct net *net, u32 bearer_id,
struct tipc_media_addr *dst);
void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
struct sk_buff_head *xmitq);
+void tipc_clone_to_loopback(struct net *net, struct sk_buff_head *xmitq);
+int tipc_attach_loopback(struct net *net);
+void tipc_detach_loopback(struct net *net);
/* check if device MTU is too low for tipc headers */
static inline bool tipc_mtu_bad(struct net_device *dev, unsigned int
reserve)
diff --git a/net/tipc/core.c b/net/tipc/core.c
index ed536c0..1867687 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -81,7 +81,9 @@ static int __net_init tipc_init_net(struct net *net)
err = tipc_bcast_init(net);
if (err)
goto out_bclink;
-
+ err = tipc_attach_loopback(net);
+ if (err)
+ goto out_bclink;
return 0;
out_bclink:
@@ -94,6 +96,7 @@ static int __net_init tipc_init_net(struct net *net)
static void __net_exit tipc_exit_net(struct net *net)
{
+ tipc_detach_loopback(net);
tipc_net_stop(net);
tipc_bcast_stop(net);
tipc_nametbl_stop(net);
diff --git a/net/tipc/core.h b/net/tipc/core.h
index 7a68e1b..de164ac 100644
--- a/net/tipc/core.h
+++ b/net/tipc/core.h
@@ -125,6 +125,10 @@ struct tipc_net {
/* Cluster capabilities */
u16 capabilities;
+
+ /* Tracing of node internal messages */
+ struct packet_type loopback_pt;
+ bool loopback_trace;
};
static inline struct tipc_net *tipc_net(struct net *net)
@@ -152,6 +156,11 @@ static inline struct tipc_topsrv *tipc_topsrv(struct
net *net)
return tipc_net(net)->topsrv;
}
+static inline bool tipc_loopback_trace(struct net *net)
+{
+ return tipc_net(net)->loopback_trace;
+}
+
static inline unsigned int tipc_hashfn(u32 addr)
{
return addr & (NODE_HTABLE_SIZE - 1);
diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c
index 99bd166..d6165ad 100644
--- a/net/tipc/netlink.c
+++ b/net/tipc/netlink.c
@@ -261,7 +261,7 @@ struct genl_family tipc_genl_family __ro_after_init = {
.version = TIPC_GENL_V2_VERSION,
.hdrsize = 0,
.maxattr = TIPC_NLA_MAX,
- .policy = tipc_nl_policy,
+ .policy = tipc_nl_policy,
.netnsok = true,
.module = THIS_MODULE,
.ops = tipc_genl_v2_ops,
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 9e106d3..415d02d 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -1439,6 +1439,8 @@ int tipc_node_xmit(struct net *net, struct
sk_buff_head *list,
int rc;
if (in_own_node(net, dnode)) {
+ if (unlikely(tipc_loopback_trace(net)))
+ tipc_clone_to_loopback(net,
list);
tipc_sk_rcv(net, list);
return 0;
}
diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c
index f345662..37f07e7 100644
--- a/net/tipc/topsrv.c
+++ b/net/tipc/topsrv.c
@@ -40,6 +40,7 @@
#include "socket.h"
#include "addr.h"
#include "msg.h"
+#include "bearer.h"
#include <net/sock.h>
#include <linux/module.h>
@@ -608,6 +609,8 @@ static void tipc_topsrv_kern_evt(struct net *net, struct
tipc_event *evt)
memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
skb_queue_head_init(&evtq);
__skb_queue_tail(&evtq, skb);
+ if (unlikely(tipc_loopback_trace(net)))
+ tipc_clone_to_loopback(net, &evtq);
tipc_sk_rcv(net, &evtq);
}
--
2.11.0
---
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