tc/pedit: Introduce 'add' operation

This command could be useful to increase/decrease fields value.

Signed-off-by: Amir Vadai <amir@vadai.me>

diff --git a/man/man8/tc-pedit.8 b/man/man8/tc-pedit.8
index 761d5c8ee2d5183b82663e14d2a544a78eaab2a7..6bba741956f1576a11c9a6b85e60532d63b12afa 100644 (file)
--- a/man/man8/tc-pedit.8
+++ b/man/man8/tc-pedit.8
@@ -43,6 +43,8 @@ pedit - generic packet editor action
 .IR CMD_SPEC " := {"
 .BR clear " | " invert " | " set
 .IR VAL " | "
+.BR add
+.IR VAL " | "
 .BR preserve " } [ " retain
 .IR RVAL " ]"
 
@@ -63,7 +65,9 @@ only for IPv4 headers.
 .B ex
 Use extended pedit.
 .I EXTENDED_LAYERED_OP
-is allowed only in this mode.
+and the add
+.I CMD_SPEC
+are allowed only in this mode.
 .TP
 .BI offset " OFFSET " "\fR{ \fBu32 \fR| \fBu16 \fR| \fBu8 \fR}"
 Specify the offset at which to change data.
@@ -173,6 +177,13 @@ keywords in
 or the size of the addressed header field in
 .IR LAYERED_OP .
 .TP
+.BI add " VAL"
+Add the addressed data by a specific value. The size of
+.I VAL
+is defined by the size of the addressed header field in
+.IR EXTENDED_LAYERED_OP .
+This operation is supported only for extended layered op.
+.TP
 .B preserve
 Keep the addressed data as is.
 .TP

diff --git a/tc/m_pedit.c b/tc/m_pedit.c
index a26fd3e5bc5e61fe619b528c993394342472ee06..7af074a5a97c27067706c91e2f5cb3b3f8fd7463 100644 (file)
--- a/tc/m_pedit.c
+++ b/tc/m_pedit.c
@@ -41,7 +41,7 @@ static void explain(void)
                "\t\tATC:= at <atval> offmask <maskval> shift <shiftval>\n"
                "\t\tNOTE: offval is byte offset, must be multiple of 4\n"
                "\t\tNOTE: maskval is a 32 bit hex number\n \t\tNOTE: shiftval is a shift value\n"
-               "\t\tCMD:= clear | invert | set <setval>| retain\n"
+               "\t\tCMD:= clear | invert | set <setval>| add <addval> | retain\n"
                "\t<LAYERED>:= ip <ipdata> | ip6 <ip6data>\n"
                " \t\t| udp <udpdata> | tcp <tcpdata> | icmp <icmpdata>\n"
                "\tCONTROL:= reclassify | pipe | drop | continue | pass\n"
@@ -276,7 +276,16 @@ int parse_cmd(int *argc_p, char ***argv_p, __u32 len, int type, __u32 retain,
 
        if (matches(*argv, "invert") == 0) {
                val = mask = o;
-       } else if (matches(*argv, "set") == 0) {
+       } else if (matches(*argv, "set") == 0 ||
+                  matches(*argv, "add") == 0) {
+               if (matches(*argv, "add") == 0)
+                       tkey->cmd = TCA_PEDIT_KEY_EX_CMD_ADD;
+
+               if (!sel->extended && tkey->cmd) {
+                       fprintf(stderr, "Non extended mode. only 'set' command is supported\n");
+                       return -1;
+               }
+
                NEXT_ARG();
                if (parse_val(&argc, &argv, &val, type))
                        return -1;
@@ -690,9 +699,11 @@ int print_pedit(struct action_util *au, FILE *f, struct rtattr *arg)
                for (i = 0; i < sel->nkeys; i++, key++) {
                        enum pedit_header_type htype =
                                TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
+                       enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 
                        if (keys_ex) {
                                htype = key_ex->htype;
+                               cmd = key_ex->cmd;
 
                                key_ex++;
                        }
@@ -703,7 +714,8 @@ int print_pedit(struct action_util *au, FILE *f, struct rtattr *arg)
 
                        print_pedit_location(f, htype, key->off);
 
-                       fprintf(f, ": val %08x mask %08x",
+                       fprintf(f, ": %s %08x mask %08x",
+                               cmd ? "add" : "val",
                                (unsigned int)ntohl(key->val),
                                (unsigned int)ntohl(key->mask));
                }