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Date:   Thu, 19 Jan 2017 16:17:48 +0200
From:   Paul Blakey <paulb@...lanox.com>
To:     Stephen Hemminger <stephen@...workplumber.org>,
        netdev@...r.kernel.org
Cc:     Jiri Pirko <jiri@...lanox.com>, Or Gerlitz <ogerlitz@...lanox.com>,
        Roi Dayan <roid@...lanox.com>, Jiri Benc <jbenc@...hat.com>,
        Simon Horman <simon.horman@...ronome.com>,
        Paul Blakey <paulb@...lanox.com>
Subject: [PATCH net-next V4] tc: flower: Refactor matching flags to be more user friendly

Instead of "magic numbers" we can now specify each flag
by name. Prefix of "no"  (e.g nofrag) unsets the flag,
otherwise it wil be set.

Example:
    # add a flower filter that will drop fragmented packets
    tc filter add dev ens4f0 protocol ip parent ffff: \
            flower \
            src_mac e4:1d:2d:fd:8b:01 \
            dst_mac e4:1d:2d:fd:8b:02 \
            indev ens4f0 \
            ip_flags frag \
    action drop

    # add a flower filter that will drop non-fragmented packets
    tc filter add dev ens4f0 protocol ip parent ffff: \
            flower \
            src_mac e4:1d:2d:fd:8b:01 \
            dst_mac e4:1d:2d:fd:8b:02 \
            indev ens4f0 \
            ip_flags nofrag \
    action drop

Fixes: 22a8f019891c ('tc: flower: support matching flags')
Signed-off-by: Paul Blakey <paulb@...lanox.com>
Reviewed-by: Roi Dayan <roid@...lanox.com>
---

Hi,
Added a framework to add new flags more easily, such 
as the upcoming tcp_flags (see kernel cls_flower), and other ip_flags.

Thanks,
     Paul.


Changelog:

v4:
Changed prefix in manpage as well.

v3:
Changed prefix to "no" instead of "no_".

v2:
Changed delimiter to "/" to avoid shell pipe errors.


 man/man8/tc-flower.8 |  12 +++++-
 tc/f_flower.c        | 117 ++++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 102 insertions(+), 27 deletions(-)

diff --git a/man/man8/tc-flower.8 b/man/man8/tc-flower.8
index 2dd2c5e..2bdd2ef 100644
--- a/man/man8/tc-flower.8
+++ b/man/man8/tc-flower.8
@@ -46,7 +46,9 @@ flower \- flow based traffic control filter
 .BR enc_dst_ip " | " enc_src_ip " } { "
 .IR ipv4_address " | " ipv6_address " } | "
 .B enc_dst_port
-.IR port_number
+.IR port_number " | "
+.BR ip_flags
+.IR IP_FLAGS
 .SH DESCRIPTION
 The
 .B flower
@@ -183,13 +185,19 @@ prefix length. If the prefix is missing, \fBtc\fR assumes a full-length
 host match.  Dst port
 .I NUMBER
 is a 16 bit UDP dst port.
+.TP
+.BI ip_flags " IP_FLAGS"
+.I IP_FLAGS
+may be either
+.BR frag " or " nofrag
+to match on fragmented packets or not respectively.
 .SH NOTES
 As stated above where applicable, matches of a certain layer implicitly depend
 on the matches of the next lower layer. Precisely, layer one and two matches
 (\fBindev\fR,  \fBdst_mac\fR and \fBsrc_mac\fR)
 have no dependency, layer three matches
 (\fBip_proto\fR, \fBdst_ip\fR, \fBsrc_ip\fR, \fBarp_tip\fR, \fBarp_sip\fR,
-\fBarp_op\fR, \fBarp_tha\fR and \fBarp_sha\fR)
+\fBarp_op\fR, \fBarp_tha\fR, \fBarp_sha\fR and \fBip_flags\fR)
 depend on the
 .B protocol
 option of tc filter, layer four port matches
diff --git a/tc/f_flower.c b/tc/f_flower.c
index d301db3..3dffe2b 100644
--- a/tc/f_flower.c
+++ b/tc/f_flower.c
@@ -24,6 +24,10 @@
 #include "tc_util.h"
 #include "rt_names.h"
 
+enum flower_matching_flags {
+	FLOWER_IP_FLAGS,
+};
+
 enum flower_endpoint {
 	FLOWER_ENDPOINT_SRC,
 	FLOWER_ENDPOINT_DST
@@ -63,7 +67,7 @@ static void explain(void)
 		"                       enc_dst_ip [ IPV4-ADDR | IPV6-ADDR ] |\n"
 		"                       enc_src_ip [ IPV4-ADDR | IPV6-ADDR ] |\n"
 		"                       enc_key_id [ KEY-ID ] |\n"
-		"                       matching_flags MATCHING-FLAGS | \n"
+		"                       ip_flags IP-FLAGS | \n"
 		"                       enc_dst_port [ port_number ] }\n"
 		"       FILTERID := X:Y:Z\n"
 		"       MASKED_LLADDR := { LLADDR | LLADDR/MASK | LLADDR/BITS }\n"
@@ -136,28 +140,56 @@ static int flower_parse_vlan_eth_type(char *str, __be16 eth_type, int type,
 	return 0;
 }
 
-static int flower_parse_matching_flags(char *str, int type, int mask_type,
-				       struct nlmsghdr *n)
-{
-	__u32 mtf, mtf_mask;
-	char *c;
+struct flag_to_string {
+	int flag;
+	enum flower_matching_flags type;
+	char *string;
+};
 
-	c = strchr(str, '/');
-	if (c)
-		*c = '\0';
+static struct flag_to_string flags_str[] = {
+	{ TCA_FLOWER_KEY_FLAGS_IS_FRAGMENT, FLOWER_IP_FLAGS, "frag" },
+};
 
-	if (get_u32(&mtf, str, 0))
-		return -1;
+static int flower_parse_matching_flags(char *str,
+				       enum flower_matching_flags type,
+				       __u32 *mtf, __u32 *mtf_mask)
+{
+	char *token;
+	bool no;
+	bool found;
+	int i;
 
-	if (c) {
-		if (get_u32(&mtf_mask, ++c, 0))
+	token = strtok(str, "/");
+
+	while (token) {
+		if (!strncmp(token, "no", 2)) {
+			no = true;
+			token = strchr(token, '_') + 1;
+		} else
+			no = false;
+
+		found = false;
+		for (i = 0; i < ARRAY_SIZE(flags_str); i++) {
+			if (type != flags_str[i].type)
+				continue;
+
+			if (!strcmp(token, flags_str[i].string)) {
+				if (no)
+					*mtf &= ~flags_str[i].flag;
+				else
+					*mtf |= flags_str[i].flag;
+
+				*mtf_mask |= flags_str[i].flag;
+				found = true;
+				break;
+			}
+		}
+		if (!found)
 			return -1;
-	} else {
-		mtf_mask = 0xffffffff;
+
+		token = strtok(NULL, "/");
 	}
 
-	addattr32(n, MAX_MSG, type, htonl(mtf));
-	addattr32(n, MAX_MSG, mask_type, htonl(mtf_mask));
 	return 0;
 }
 
@@ -433,6 +465,8 @@ static int flower_parse_opt(struct filter_util *qu, char *handle,
 	__be16 vlan_ethtype = 0;
 	__u8 ip_proto = 0xff;
 	__u32 flags = 0;
+	__u32 mtf = 0;
+	__u32 mtf_mask = 0;
 
 	if (handle) {
 		ret = get_u32(&t->tcm_handle, handle, 0);
@@ -462,14 +496,14 @@ static int flower_parse_opt(struct filter_util *qu, char *handle,
 				return -1;
 			}
 			addattr_l(n, MAX_MSG, TCA_FLOWER_CLASSID, &handle, 4);
-		} else if (matches(*argv, "matching_flags") == 0) {
+		} else if (matches(*argv, "ip_flags") == 0) {
 			NEXT_ARG();
 			ret = flower_parse_matching_flags(*argv,
-							  TCA_FLOWER_KEY_FLAGS,
-							  TCA_FLOWER_KEY_FLAGS_MASK,
-							  n);
+							  FLOWER_IP_FLAGS,
+							  &mtf,
+							  &mtf_mask);
 			if (ret < 0) {
-				fprintf(stderr, "Illegal \"matching_flags\"\n");
+				fprintf(stderr, "Illegal \"ip_flags\"\n");
 				return -1;
 			}
 		} else if (matches(*argv, "skip_hw") == 0) {
@@ -723,6 +757,16 @@ static int flower_parse_opt(struct filter_util *qu, char *handle,
 parse_done:
 	addattr32(n, MAX_MSG, TCA_FLOWER_FLAGS, flags);
 
+	if (mtf_mask) {
+		ret = addattr32(n, MAX_MSG, TCA_FLOWER_KEY_FLAGS, htonl(mtf));
+		if (ret)
+			return ret;
+
+		ret = addattr32(n, MAX_MSG, TCA_FLOWER_KEY_FLAGS_MASK, htonl(mtf_mask));
+		if (ret)
+			return ret;
+	}
+
 	ret = addattr16(n, MAX_MSG, TCA_FLOWER_KEY_ETH_TYPE, eth_type);
 	if (ret) {
 		fprintf(stderr, "Illegal \"eth_type\"(0x%x)\n",
@@ -828,14 +872,36 @@ static void flower_print_ip_proto(FILE *f, __u8 *p_ip_proto,
 }
 
 static void flower_print_matching_flags(FILE *f, char *name,
+					enum flower_matching_flags type,
 					struct rtattr *attr,
 					struct rtattr *mask_attr)
 {
+	int i;
+	int count = 0;
+	__u32 mtf;
+	__u32 mtf_mask;
+
 	if (!mask_attr || RTA_PAYLOAD(mask_attr) != 4)
 		return;
 
-	fprintf(f, "\n  %s 0x%08x/0x%08x", name, ntohl(rta_getattr_u32(attr)),
-		mask_attr ? ntohl(rta_getattr_u32(mask_attr)) : 0xffffffff);
+	mtf = ntohl(rta_getattr_u32(attr));
+	mtf_mask = ntohl(rta_getattr_u32(mask_attr));
+
+	for (i = 0; i < ARRAY_SIZE(flags_str); i++) {
+		if (type != flags_str[i].type)
+			continue;
+		if (mtf_mask & flags_str[i].flag) {
+			if (++count == 1)
+				fprintf(f, "\n  %s ", name);
+			else
+				fprintf(f, "/");
+
+			if (mtf & flags_str[i].flag)
+				fprintf(f, "%s", flags_str[i].string);
+			else
+				fprintf(f, "no%s", flags_str[i].string);
+		}
+	}
 }
 
 static void flower_print_ip_addr(FILE *f, char *name, __be16 eth_type,
@@ -1034,7 +1100,8 @@ static int flower_print_opt(struct filter_util *qu, FILE *f,
 	flower_print_port(f, "enc_dst_port",
 			  tb[TCA_FLOWER_KEY_ENC_UDP_DST_PORT]);
 
-	flower_print_matching_flags(f, "matching_flags",
+	flower_print_matching_flags(f, "ip_flags",
+				    FLOWER_IP_FLAGS,
 				    tb[TCA_FLOWER_KEY_FLAGS],
 				    tb[TCA_FLOWER_KEY_FLAGS_MASK]);
 
-- 
2.7.4

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