tc: add NLM_F_ECHO support for actions

This patch adds the -echo flag to tc command line and support for it in
tc actions. If the user specifies this flag for an action command, the
kernel will return the command's result back to user space.
For example:

  tc -echo actions add action mirred egress mirror dev lo

  total acts 0
  Added action
        action order 1: mirred (Egress Mirror to device lo) pipe
        index 10 ref 1 bind 0
        not_in_hw

As illustrated above, the kernel will give us an index of 10

The same can be done for other action commands (replace, change, and
delete). For example:

  tc -echo actions delete action mirred index 10

  total acts 0
  Deleted action
        action order 1: mirred (Egress Mirror to device lo) pipe
        index 10 ref 0 bind 0
        not_in_hw

Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

diff --git a/man/man8/tc.8 b/man/man8/tc.8
index 3175454b9d60b08959104c8605ec7a71b7d5f253..dce58af172e994a951c2cb8caff79ac09d2d8348 100644 (file)
--- a/man/man8/tc.8
+++ b/man/man8/tc.8
@@ -127,7 +127,7 @@ tc \- show / manipulate traffic control settings
 \fB[ \fB-nm \fR| \fB-nam\fR[\fIes\fR] \fB] \fR|
 \fB[ \fR{ \fB-cf \fR| \fB-c\fR[\fIonf\fR] \fR} \fB[ filename ] \fB] \fR
 \fB[ -t\fR[imestamp\fR] \fB\] \fR| \fB[ -t\fR[short\fR] \fR| \fB[
--o\fR[neline\fR] \fB]\fR }
+-o\fR[neline\fR] \fB] \fR| \fB[ -echo ]\fR }
 
 .ti 8
 .IR FORMAT " := {"
@@ -743,6 +743,10 @@ When\fB\ tc monitor\fR\ runs, print timestamp before the event message in format
 When\fB\ tc monitor\fR\ runs, prints short timestamp before the event message in format:
    [<YYYY>-<MM>-<DD>T<hh:mm:ss>.<ms>]
 
+.TP
+.BR "\-echo"
+Request the kernel to send the applied configuration back.
+
 .SH FORMAT
 The show command has additional formatting options:
 

diff --git a/tc/m_action.c b/tc/m_action.c
index 16474c56118c115f16d6dc57a13b57944426282b..fd9621e1ba52d501a52ddfb64dd79089143ed758 100644 (file)
--- a/tc/m_action.c
+++ b/tc/m_action.c
@@ -688,7 +688,16 @@ static int tc_action_gd(int cmd, unsigned int flags,
 
        req.n.nlmsg_seq = rth.dump = ++rth.seq;
 
-       if (rtnl_talk(&rth, &req.n, cmd == RTM_DELACTION ? NULL : &ans) < 0) {
+       if (cmd == RTM_DELACTION) {
+               if (echo_request)
+                       ret = rtnl_echo_talk(&rth, &req.n, json, print_action);
+               else
+                       ret = rtnl_talk(&rth, &req.n, NULL);
+       } else {
+               ret = rtnl_talk(&rth, &req.n, &ans);
+       }
+
+       if (ret < 0) {
                fprintf(stderr, "We have an error talking to the kernel\n");
                return 1;
        }
@@ -738,7 +747,12 @@ static int tc_action_modify(int cmd, unsigned int flags,
        }
        tail->rta_len = (void *) NLMSG_TAIL(&req.n) - (void *) tail;
 
-       if (rtnl_talk(&rth, &req.n, NULL) < 0) {
+       if (echo_request)
+               ret = rtnl_echo_talk(&rth, &req.n, json, print_action);
+       else
+               ret = rtnl_talk(&rth, &req.n, NULL);
+
+       if (ret < 0) {
                fprintf(stderr, "We have an error talking to the kernel\n");
                ret = -1;
        }
@@ -836,7 +850,12 @@ static int tc_act_list_or_flush(int *argc_p, char ***argv_p, int event)
                req.n.nlmsg_type = RTM_DELACTION;
                req.n.nlmsg_flags |= NLM_F_ROOT;
                req.n.nlmsg_flags |= NLM_F_REQUEST;
-               if (rtnl_talk(&rth, &req.n, NULL) < 0) {
+
+               if (echo_request)
+                       ret = rtnl_echo_talk(&rth, &req.n, json, print_action);
+               else
+                       ret = rtnl_talk(&rth, &req.n, NULL);
+               if (ret < 0) {
                        fprintf(stderr, "We have an error flushing\n");
                        return 1;
                }

diff --git a/tc/tc.c b/tc/tc.c
index 575157a860d585ea57856c8353fe2b483cdc2c34..7a746cf5115e55e2a076942c920aaae735fdad85 100644 (file)
--- a/tc/tc.c
+++ b/tc/tc.c
@@ -38,6 +38,8 @@ int json;
 int oneline;
 int brief;
 
+int echo_request;
+
 static char *conf_file;
 
 struct rtnl_handle rth;
@@ -196,7 +198,7 @@ static void usage(void)
                "                   -o[neline] | -j[son] | -p[retty] | -c[olor]\n"
                "                   -b[atch] [filename] | -n[etns] name | -N[umeric] |\n"
                "                    -nm | -nam[es] | { -cf | -conf } path\n"
-               "                    -br[ief] }\n");
+               "                    -br[ief] | -echo }\n");
 }
 
 static int do_cmd(int argc, char **argv)
@@ -314,6 +316,8 @@ int main(int argc, char **argv)
                        ++oneline;
                } else if (matches(argv[1], "-brief") == 0) {
                        ++brief;
+               } else if (strcmp(argv[1], "-echo") == 0) {
+                       ++echo_request;
                } else {
                        fprintf(stderr,
                                "Option \"%s\" is unknown, try \"tc -help\".\n",