pbrd: dscp interpret standard codepoints

Matching by dscp may now also be specified by its standard codepoint
(provided it has one), such as `cf0` or `af11`.

Signed-off-by: Wesley Coakley <wcoakley@nvidia.com>

doc/user/pbr.rst

@@ -123,11 +123,15 @@ end destination.
    on another platform it will be denied.  This mark translates to the
    underlying `ip rule .... fwmark XXXX` command.
 
-.. clicmd:: match dscp (0-63)
+.. clicmd:: match dscp (DSCP|0-63)
 
    Match packets according to the specified differentiated services code point
    (DSCP) in the IP header; if this value matches then forward the packet
-   according to the nexthop(s) specified.
+   according to the nexthop(s) specified. The passed DSCP value may also be a
+   standard name for a differentiated service code point like cs0 or af11.
+
+   You may only specify one dscp per route map sequence; to match on multiple
+   dscp values you will need to create several sequences, one for each value.
 
 .. clicmd:: match ecn (0-3)
 

pbrd/pbr_map.c

@@ -444,6 +444,59 @@ static void pbr_map_add_interfaces(struct pbr_map *pbrm)
 	}
 }
 
+/* Decodes a standardized DSCP into its representative value */
+uint8_t pbr_map_decode_dscp_enum(const char *name)
+{
+	/* Standard Differentiated Services Field Codepoints */
+	if (!strcmp(name, "cs0"))
+		return 0;
+	if (!strcmp(name, "cs1"))
+		return 8;
+	if (!strcmp(name, "cs2"))
+		return 16;
+	if (!strcmp(name, "cs3"))
+		return 24;
+	if (!strcmp(name, "cs4"))
+		return 32;
+	if (!strcmp(name, "cs5"))
+		return 40;
+	if (!strcmp(name, "cs6"))
+		return 48;
+	if (!strcmp(name, "cs7"))
+		return 56;
+	if (!strcmp(name, "af11"))
+		return 10;
+	if (!strcmp(name, "af12"))
+		return 12;
+	if (!strcmp(name, "af13"))
+		return 14;
+	if (!strcmp(name, "af21"))
+		return 18;
+	if (!strcmp(name, "af22"))
+		return 20;
+	if (!strcmp(name, "af23"))
+		return 22;
+	if (!strcmp(name, "af31"))
+		return 26;
+	if (!strcmp(name, "af32"))
+		return 28;
+	if (!strcmp(name, "af33"))
+		return 30;
+	if (!strcmp(name, "af41"))
+		return 34;
+	if (!strcmp(name, "af42"))
+		return 36;
+	if (!strcmp(name, "af43"))
+		return 38;
+	if (!strcmp(name, "ef"))
+		return 46;
+	if (!strcmp(name, "voice-admit"))
+		return 44;
+
+	/* No match? Error out */
+	return -1;
+}
+
 struct pbr_map_sequence *pbrms_get(const char *name, uint32_t seqno)
 {
 	struct pbr_map *pbrm;

pbrd/pbr_map.h

@@ -169,6 +169,8 @@ extern void pbr_map_add_interface(struct pbr_map *pbrm, struct interface *ifp);
 extern void pbr_map_interface_delete(struct pbr_map *pbrm,
 				     struct interface *ifp);
 
+extern uint8_t pbr_map_decode_dscp_enum(const char *name);
+
 /* Update maps installed on interface */
 extern void pbr_map_policy_interface_update(const struct interface *ifp,
 					    bool state_up);

pbrd/pbr_vty.c

@@ -184,21 +184,57 @@ DEFPY(pbr_map_match_dst, pbr_map_match_dst_cmd,
 }
 
 DEFPY(pbr_map_match_dscp, pbr_map_match_dscp_cmd,
-      "[no] match dscp (0-63)$dscp",
+      "[no] match dscp DSCP$dscp",
       NO_STR
       "Match the rest of the command\n"
       "Match based on IP DSCP field\n"
-      "Differentiated Service Code Point\n")
+      "DSCP value (below 64) or standard codepoint name\n")
 {
 	struct pbr_map_sequence *pbrms = VTY_GET_CONTEXT(pbr_map_sequence);
+	char dscpname[100];
+	uint8_t rawDscp;
+
+	/* Discriminate dscp enums (cs0, cs1 etc.) and numbers */
+	bool isANumber = true;
+	for (int i = 0; i < (int)strlen(dscp); i++) {
+		/* Letters are not numbers */
+		if (!isdigit(dscp[i]))
+			isANumber = false;
+
+		/* Lowercase the dscp enum (if needed) */
+		if (isupper(dscp[i]))
+			dscpname[i] = tolower(dscp[i]);
+		else
+			dscpname[i] = dscp[i];
+	}
+	dscpname[strlen(dscp)] = '\0';
+
+	if (isANumber) {
+		/* dscp passed is a regular number */
+		long dscpAsNum = strtol(dscp, NULL, 0);
+
+		if (dscpAsNum > PBR_DSFIELD_DSCP >> 2) {
+			/* Refuse to install on overflow */
+			vty_out(vty, "dscp (%s) must be less than 64\n", dscp);
+			return CMD_WARNING_CONFIG_FAILED;
+		}
+		rawDscp = dscpAsNum;
+	} else {
+		/* check dscp if it is an enum like cs0 */
+		rawDscp = pbr_map_decode_dscp_enum(dscpname);
+		if (rawDscp > PBR_DSFIELD_DSCP) {
+			vty_out(vty, "Invalid dscp value: %s\n", dscpname);
+			return CMD_WARNING_CONFIG_FAILED;
+		}
+	}
 
 	if (!no) {
-		if (((pbrms->dsfield & PBR_DSFIELD_DSCP) >> 2) == dscp)
+		if (((pbrms->dsfield & PBR_DSFIELD_DSCP) >> 2) == rawDscp)
 			return CMD_SUCCESS;
 
 		/* Set the DSCP bits of the DSField */
 		pbrms->dsfield =
-			(pbrms->dsfield & ~PBR_DSFIELD_DSCP) | (dscp << 2);
+			(pbrms->dsfield & ~PBR_DSFIELD_DSCP) | (rawDscp << 2);
 	} else {
 		pbrms->dsfield &= ~PBR_DSFIELD_DSCP;
 	}
@@ -614,8 +650,6 @@ static void vty_show_pbrms(struct vty *vty,
 	if (pbrms->dsfield & PBR_DSFIELD_ECN)
 		vty_out(vty, "        ECN Match: %u\n",
 			pbrms->dsfield & PBR_DSFIELD_ECN);
-	if (pbrms->dsfield)
-		vty_out(vty, "        DSField Match: %u\n", (pbrms->dsfield));
 	if (pbrms->mark)
 		vty_out(vty, "        MARK Match: %u\n", pbrms->mark);