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tc: B.W limits can now be specified in %.

PATCH Superseded Nishanth Devarajan 3 participants 3 messages Nov 15, 2017

Subsystems (3)
Networking Network drivers Library code

v2 of 4 Superseded Latest is v4 →

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Nishanth Devarajan

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PATCH v2 1/1 tc: B.W limits can now be specified in %.

This patch adapts the tc command line interface to allow bandwidth limits to be specified as a percentage of the interface's capacity.

For this purpose, we've modified and moved int read_prop() from ip/iptuntap.c to lib.utils.c to make it accessible to tc.

Additionally, adding this functionality requires passing the specified device string to each class/qdisc which changes the prototype for a couple of functions: the .parse_qopt and .parse_copt interfaces. The device string is a required parameter for tc-qdisc and tc-class, and when not specified, the kernel returns ENODEV. In this patch, if the user tries to specify a bandwidth percentage without naming the device, we return an error from userspace.

Signed-off by: Nishanth Devarajan <[email protected]>

---
 include/utils.h |  1 +
 ip/iptuntap.c   | 32 ----------------------------
 lib/utils.c     | 51 ++++++++++++++++++++++++++++++++++++++++++++
 man/man8/tc.8   |  4 +++-
 tc/q_atm.c      |  2 +-
 tc/q_cbq.c      | 25 +++++++++++++++++-----
 tc/q_choke.c    |  9 ++++++--
 tc/q_clsact.c   |  2 +-
 tc/q_codel.c    |  2 +-
 tc/q_drr.c      |  4 ++--
 tc/q_dsmark.c   |  4 ++--
 tc/q_fifo.c     |  2 +-
 tc/q_fq.c       | 16 +++++++++++---
 tc/q_fq_codel.c |  2 +-
 tc/q_gred.c     |  9 ++++++--
 tc/q_hfsc.c     | 45 ++++++++++++++++++++++++++-------------
 tc/q_hhf.c      |  2 +-
 tc/q_htb.c      | 18 ++++++++++++----
 tc/q_ingress.c  |  2 +-
 tc/q_mqprio.c   |  2 +-
 tc/q_multiq.c   |  2 +-
 tc/q_netem.c    |  9 ++++++--
 tc/q_pie.c      |  2 +-
 tc/q_prio.c     |  2 +-
 tc/q_qfq.c      |  4 ++--
 tc/q_red.c      |  9 ++++++--
 tc/q_rr.c       |  2 +-
 tc/q_sfb.c      |  2 +-
 tc/q_sfq.c      |  2 +-
 tc/q_tbf.c      | 16 +++++++++++---
 tc/tc.c         |  2 +-
 tc/tc_class.c   |  2 +-
 tc/tc_qdisc.c   |  2 +-
 tc/tc_util.c    | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tc/tc_util.h    |  8 +++++--
 35 files changed, 268 insertions(+), 96 deletions(-)
include/utils.h +1 -0
index 3d91c50..63fea7c 100644
@@ -87,6 +87,7 @@ int get_prefix(inet_prefix *dst, char *arg, int family);
 int mask2bits(__u32 netmask);
 int get_addr_ila(__u64 *val, const char *arg);
 
+int read_prop(char *dev, char *prop, long *value);
 int get_hex(char c);
 int get_integer(int *val, const char *arg, int base);
 int get_unsigned(unsigned *val, const char *arg, int base);
ip/iptuntap.c +0 -32
index b46e452..09f2be2 100644
@@ -223,38 +223,6 @@ static int do_del(int argc, char **argv)
 	return tap_del_ioctl(&ifr);
 }
 
-static int read_prop(char *dev, char *prop, long *value)
-{
-	char fname[IFNAMSIZ+25], buf[80], *endp;
-	ssize_t len;
-	int fd;
-	long result;
-
-	sprintf(fname, "/sys/class/net/%s/%s", dev, prop);
-	fd = open(fname, O_RDONLY);
-	if (fd < 0) {
-		if (strcmp(prop, "tun_flags"))
-			fprintf(stderr, "open %s: %s\n", fname,
-				strerror(errno));
-		return -1;
-	}
-	len = read(fd, buf, sizeof(buf)-1);
-	close(fd);
-	if (len < 0) {
-		fprintf(stderr, "read %s: %s", fname, strerror(errno));
-		return -1;
-	}
-
-	buf[len] = 0;
-	result = strtol(buf, &endp, 0);
-	if (*endp != '\n') {
-		fprintf(stderr, "Failed to parse %s\n", fname);
-		return -1;
-	}
-	*value = result;
-	return 0;
-}
-
 static void print_flags(long flags)
 {
 	if (flags & IFF_TUN)
lib/utils.c +51 -0

57 lines not on this page · raw message

man/man8/tc.8 +3 -1
index f96911a..22f699b 100644
@@ -443,7 +443,9 @@ see the man pages for individual qdiscs.
 RATES
 Bandwidths or rates.
 These parameters accept a floating point number, possibly followed by
-a unit (both SI and IEC units supported).
+either a unit (both SI and IEC units supported), or a float followed '%'
+character to specify the rate as a percentage of the device's speed
+(e.g. 5%, 99.5%).
 .RS
 .TP
 bit or a bare number
tc/q_atm.c +1 -1
index 570e7be..7dfd811 100644
@@ -44,7 +44,7 @@ static void explain(void)
 
 
 static int atm_parse_class_opt(struct qdisc_util *qu, int argc, char **argv,
-   struct nlmsghdr *n)
+	struct nlmsghdr *n, char *dev)
 {
 	struct sockaddr_atmsvc addr = {};
 	struct atm_qos qos;
tc/q_cbq.c +20 -5
index e00d4e3..284a874 100644
@@ -46,7 +46,7 @@ static void explain1(char *arg)
 }
 
 
-static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	struct tc_ratespec r = {};
 	struct tc_cbq_lssopt lss = {};

@@ -62,7 +62,12 @@ static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 		if (matches(*argv, "bandwidth") == 0 ||
 		    matches(*argv, "rate") == 0) {
 			NEXT_ARG();
-			if (get_rate(&r.rate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&r.rate, *argv, dev)) {
+					explain1("bandwidth");
+					return -1;
+				}
+			} else if (get_rate(&r.rate, *argv)) {
 				explain1("bandwidth");
 				return -1;
 			}

@@ -176,7 +181,7 @@ static int cbq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 	return 0;
 }
 
-static int cbq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int cbq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int wrr_ok = 0, fopt_ok = 0;
 	struct tc_ratespec r = {};

@@ -196,13 +201,23 @@ static int cbq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, str
 	while (argc > 0) {
 		if (matches(*argv, "rate") == 0) {
 			NEXT_ARG();
-			if (get_rate(&r.rate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&r.rate, *argv, dev)) {
+					explain1("rate");
+					return -1;
+				}
+			} else if (get_rate(&r.rate, *argv)) {
 				explain1("rate");
 				return -1;
 			}
 		} else if (matches(*argv, "bandwidth") == 0) {
 			NEXT_ARG();
-			if (get_rate(&bndw, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&bndw, *argv, dev)) {
+					explain1("bandwidth");
+					return -1;
+				}
+			} else if (get_rate(&bndw, *argv)) {
 				explain1("bandwidth");
 				return -1;
 			}
tc/q_choke.c +7 -2
index 726914b..17d70a4 100644
@@ -31,7 +31,7 @@ static void explain(void)
 }
 
 static int choke_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			   struct nlmsghdr *n)
+			   struct nlmsghdr *n, char *dev)
 {
 	struct tc_red_qopt opt = {};
 	unsigned int burst = 0;

@@ -53,7 +53,12 @@ static int choke_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 			}
 		} else if (strcmp(*argv, "bandwidth") == 0) {
 			NEXT_ARG();
-			if (get_rate(&rate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&rate, *argv, dev)) {
+					fprintf(stderr, "Illegal \"bandwidth\"\n");
+					return -1;
+				}
+			} else if (get_rate(&rate, *argv)) {
 				fprintf(stderr, "Illegal \"bandwidth\"\n");
 				return -1;
 			}
tc/q_clsact.c +1 -1
index e2a1a71..89028e6 100644
@@ -10,7 +10,7 @@ static void explain(void)
 }
 
 static int clsact_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			    struct nlmsghdr *n)
+			    struct nlmsghdr *n, char *dev)
 {
 	if (argc > 0) {
 		fprintf(stderr, "What is \"%s\"?\n", *argv);
tc/q_codel.c +1 -1
index 253629e..170cd0a 100644
@@ -58,7 +58,7 @@ static void explain(void)
 }
 
 static int codel_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			   struct nlmsghdr *n)
+			   struct nlmsghdr *n, char *dev)
 {
 	unsigned int limit = 0;
 	unsigned int target = 0;
tc/q_drr.c +2 -2
index 50623c2..3085268 100644
@@ -33,7 +33,7 @@ static void explain2(void)
 }
 
 
-static int drr_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int drr_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	while (argc) {
 		if (strcmp(*argv, "help") == 0) {

@@ -49,7 +49,7 @@ static int drr_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 }
 
 static int drr_parse_class_opt(struct qdisc_util *qu, int argc, char **argv,
-			       struct nlmsghdr *n)
+			       struct nlmsghdr *n, char *dev)
 {
 	struct rtattr *tail;
 	__u32 tmp;
tc/q_dsmark.c +2 -2
index 0aab387..13d2d31 100644
@@ -25,7 +25,7 @@ static void explain(void)
 
 
 static int dsmark_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-    struct nlmsghdr *n)
+	struct nlmsghdr *n, char *dev)
 {
 	struct rtattr *tail;
 	__u16 ind;

@@ -84,7 +84,7 @@ static void explain_class(void)
 
 
 static int dsmark_parse_class_opt(struct qdisc_util *qu, int argc, char **argv,
-   struct nlmsghdr *n)
+	struct nlmsghdr *n, char *dev)
 {
 	struct rtattr *tail;
 	__u8 tmp;
tc/q_fifo.c +1 -1
index c3e9088..f0ff1ab 100644
@@ -27,7 +27,7 @@ static void explain(void)
 	fprintf(stderr, "Usage: ... <[p|b]fifo | pfifo_head_drop> [ limit NUMBER ]\n");
 }
 
-static int fifo_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int fifo_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int ok = 0;
 	struct tc_fifo_qopt opt = {};
tc/q_fq.c +13 -3
index 49ebeef..9b0bb93 100644
@@ -71,7 +71,7 @@ static unsigned int ilog2(unsigned int val)
 }
 
 static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			struct nlmsghdr *n)
+			struct nlmsghdr *n, char *dev)
 {
 	unsigned int plimit;
 	unsigned int flow_plimit;

@@ -118,7 +118,12 @@ static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 			}
 		} else if (strcmp(*argv, "maxrate") == 0) {
 			NEXT_ARG();
-			if (get_rate(&maxrate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&maxrate, *argv, dev)) {
+					fprintf(stderr, "Illegal \"maxrate\"\n");
+					return -1;
+				}
+			} else if (get_rate(&maxrate, *argv)) {
 				fprintf(stderr, "Illegal \"maxrate\"\n");
 				return -1;
 			}

@@ -132,7 +137,12 @@ static int fq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 			set_low_rate_threshold = true;
 		} else if (strcmp(*argv, "defrate") == 0) {
 			NEXT_ARG();
-			if (get_rate(&defrate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&defrate, *argv, dev)) {
+					fprintf(stderr, "Illegal \"defrate\"\n");
+					return -1;
+				}
+			} else if (get_rate(&defrate, *argv)) {
 				fprintf(stderr, "Illegal \"defrate\"\n");
 				return -1;
 			}
tc/q_fq_codel.c +1 -1
index 1eac140..ef700cd 100644
@@ -56,7 +56,7 @@ static void explain(void)
 }
 
 static int fq_codel_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			      struct nlmsghdr *n)
+			      struct nlmsghdr *n, char *dev)
 {
 	unsigned int limit = 0;
 	unsigned int flows = 0;
tc/q_gred.c +7 -2
index 2eb906d..18d96c9 100644
@@ -116,7 +116,7 @@ static int init_gred(struct qdisc_util *qu, int argc, char **argv,
 /*
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 */
-static int gred_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int gred_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int ok = 0;
 	struct tc_gred_qopt opt = { 0 };

@@ -199,7 +199,12 @@ static int gred_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct n
 			ok++;
 		} else if (strcmp(*argv, "bandwidth") == 0) {
 			NEXT_ARG();
-			if (get_rate(&rate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&rate, *argv, dev)) {
+					fprintf(stderr, "Illegal \"bandwidth\"\n");
+					return -1;
+				}
+			} else if (get_rate(&rate, *argv)) {
 				fprintf(stderr, "Illegal \"bandwidth\"\n");
 				return -1;
 			}
tc/q_hfsc.c +30 -15

124 lines not on this page · raw message

tc/q_hhf.c +1 -1
index d1f15f9..c60d425 100644
@@ -25,7 +25,7 @@ static void explain(void)
 }
 
 static int hhf_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			 struct nlmsghdr *n)
+			 struct nlmsghdr *n, char *dev)
 {
 	unsigned int limit = 0;
 	unsigned int quantum = 0;
tc/q_htb.c +14 -4
index db82852..fb52e72 100644
@@ -59,7 +59,7 @@ static void explain1(char *arg)
 }
 
 
-static int htb_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int htb_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	unsigned int direct_qlen = ~0U;
 	struct tc_htb_glob opt = {

@@ -108,7 +108,7 @@ static int htb_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 	return 0;
 }
 
-static int htb_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int htb_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int ok = 0;
 	struct tc_htb_opt opt = {};

@@ -178,7 +178,12 @@ static int htb_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, str
 				fprintf(stderr, "Double \"ceil\" spec\n");
 				return -1;
 			}
-			if (get_rate64(&ceil64, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate64(&ceil64, *argv, dev)) {
+					explain1("ceil");
+					return -1;
+				}
+			} else if (get_rate64(&ceil64, *argv)) {
 				explain1("ceil");
 				return -1;
 			}

@@ -189,7 +194,12 @@ static int htb_parse_class_opt(struct qdisc_util *qu, int argc, char **argv, str
 				fprintf(stderr, "Double \"rate\" spec\n");
 				return -1;
 			}
-			if (get_rate64(&rate64, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate64(&rate64, *argv, dev)) {
+					explain1("rate");
+					return -1;
+				}
+			} else if (get_rate64(&rate64, *argv)) {
 				explain1("rate");
 				return -1;
 			}
tc/q_ingress.c +1 -1
index 31699a8..0ffd82c 100644
@@ -21,7 +21,7 @@ static void explain(void)
 }
 
 static int ingress_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			     struct nlmsghdr *n)
+			     struct nlmsghdr *n, char *dev)
 {
 	while (argc > 0) {
 		if (strcmp(*argv, "handle") == 0) {
tc/q_mqprio.c +1 -1
index 9979852..b568eea 100644
@@ -33,7 +33,7 @@ static void explain(void)
 }
 
 static int mqprio_parse_opt(struct qdisc_util *qu, int argc,
-			    char **argv, struct nlmsghdr *n)
+			    char **argv, struct nlmsghdr *n, char *dev)
 {
 	int idx;
 	struct tc_mqprio_qopt opt = {
tc/q_multiq.c +1 -1
index ce91fe8..f91ad3a 100644
@@ -40,7 +40,7 @@ static void explain(void)
 }
 
 static int multiq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			    struct nlmsghdr *n)
+			    struct nlmsghdr *n, char *dev)
 {
 	struct tc_multiq_qopt opt = {};
tc/q_netem.c +7 -2
index 82eb46f..0b7b1df 100644
@@ -167,7 +167,7 @@ static int get_ticks(__u32 *ticks, const char *str)
 }
 
 static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			   struct nlmsghdr *n)
+			   struct nlmsghdr *n, char *dev)
 {
 	int dist_size = 0;
 	struct rtattr *tail;

@@ -396,7 +396,12 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 		} else if (matches(*argv, "rate") == 0) {
 			++present[TCA_NETEM_RATE];
 			NEXT_ARG();
-			if (get_rate64(&rate64, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate64(&rate64, *argv, dev)) {
+					explain1("rate");
+					return -1;
+				}
+			} else if (get_rate64(&rate64, *argv)) {
 				explain1("rate");
 				return -1;
 			}
tc/q_pie.c +1 -1
index db72add..b331bb9 100644
@@ -39,7 +39,7 @@ static void explain(void)
 #define BETA_MAX 32
 
 static int pie_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			 struct nlmsghdr *n)
+			 struct nlmsghdr *n, char *dev)
 {
 	unsigned int limit   = 0;
 	unsigned int target  = 0;
tc/q_prio.c +1 -1
index 677e25a..bdfc414 100644
@@ -27,7 +27,7 @@ static void explain(void)
 	fprintf(stderr, "Usage: ... prio bands NUMBER priomap P1 P2...[multiqueue]\n");
 }
 
-static int prio_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int prio_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int pmap_mode = 0;
 	int idx = 0;
tc/q_qfq.c +2 -2
index fa270c8..91f683d 100644
@@ -35,7 +35,7 @@ static void explain_class(void)
 }
 
 static int qfq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			 struct nlmsghdr *n)
+			 struct nlmsghdr *n, char *dev)
 {
 	if (argc > 0) {
 		if (matches(*argv, "help") != 0)

@@ -48,7 +48,7 @@ static int qfq_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 }
 
 static int qfq_parse_class_opt(struct qdisc_util *qu, int argc, char **argv,
-			       struct nlmsghdr *n)
+			       struct nlmsghdr *n, char *dev)
 {
 	struct rtattr *tail;
 	__u32 tmp;
tc/q_red.c +7 -2
index 1564d6e..ddd78b0 100644
@@ -32,7 +32,7 @@ static void explain(void)
 	fprintf(stderr, "               [ecn] [harddrop]\n");
 }
 
-static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	struct tc_red_qopt opt = {};
 	unsigned int burst = 0;

@@ -83,7 +83,12 @@ static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 			}
 		} else if (strcmp(*argv, "bandwidth") == 0) {
 			NEXT_ARG();
-			if (get_rate(&rate, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate(&rate, *argv, dev)) {
+					fprintf(stderr, "Illegal \"bandwidth\"\n");
+					return -1;
+				}
+			} else if (get_rate(&rate, *argv)) {
 				fprintf(stderr, "Illegal \"bandwidth\"\n");
 				return -1;
 			}
tc/q_rr.c +1 -1
index 71ce3ce..341d506 100644
@@ -28,7 +28,7 @@ static void explain(void)
 }
 
 
-static int rr_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int rr_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int pmap_mode = 0;
 	int idx = 0;
tc/q_sfb.c +1 -1
index d074e87..4f9fa5a 100644
@@ -48,7 +48,7 @@ static int get_prob(__u32 *val, const char *arg)
 }
 
 static int sfb_parse_opt(struct qdisc_util *qu, int argc, char **argv,
-			 struct nlmsghdr *n)
+			 struct nlmsghdr *n, char *dev)
 {
 	struct tc_sfb_qopt opt = {
 		.rehash_interval = 600*1000,
tc/q_sfq.c +1 -1
index a875abd..facf2ba 100644
@@ -34,7 +34,7 @@ static void explain(void)
 	fprintf(stderr, "               [ ecn ] [ harddrop ]\n");
 }
 
-static int sfq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int sfq_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int ok = 0, red = 0;
 	struct tc_sfq_qopt_v1 opt = {};
tc/q_tbf.c +13 -3
index 4955ee4..bd59e10 100644
@@ -35,7 +35,7 @@ static void explain1(const char *arg, const char *val)
 }
 
 
-static int tbf_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int tbf_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	int ok = 0;
 	struct tc_tbf_qopt opt = {};

@@ -125,7 +125,12 @@ static int tbf_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 				fprintf(stderr, "tbf: duplicate \"rate\" specification\n");
 				return -1;
 			}
-			if (get_rate64(&rate64, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate64(&rate64, *argv, dev)) {
+					explain1("rate", *argv);
+					return -1;
+				}
+			} else if (get_rate64(&rate64, *argv)) {
 				explain1("rate", *argv);
 				return -1;
 			}

@@ -136,7 +141,12 @@ static int tbf_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nl
 				fprintf(stderr, "tbf: duplicate \"peakrate\" specification\n");
 				return -1;
 			}
-			if (get_rate64(&prate64, *argv)) {
+			if (strchr(*argv, '%')) {
+				if (get_percent_rate64(&prate64, *argv, dev)) {
+					explain1("peakrate", *argv);
+					return -1;
+				}
+			} else if (get_rate64(&prate64, *argv)) {
 				explain1("peakrate", *argv);
 				return -1;
 			}
tc/tc.c +1 -1
index fa71250..0943113 100644
@@ -59,7 +59,7 @@ static int print_noqopt(struct qdisc_util *qu, FILE *f,
 	return 0;
 }
 
-static int parse_noqopt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+static int parse_noqopt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, char *dev)
 {
 	if (argc) {
 		fprintf(stderr, "Unknown qdisc \"%s\", hence option \"%s\" is unparsable\n", qu->id, *argv);
tc/tc_class.c +1 -1
index c4a6a25..912c65f 100644
@@ -128,7 +128,7 @@ static int tc_class_modify(int cmd, unsigned int flags, int argc, char **argv)
 			fprintf(stderr, "Error: Qdisc \"%s\" is classless.\n", k);
 			return 1;
 		}
-		if (q->parse_copt(q, argc, argv, &req.n))
+		if (q->parse_copt(q, argc, argv, &req.n, d))
 			return 1;
 	} else {
 		if (argc) {
tc/tc_qdisc.c +1 -1
index fcb75f2..727d1bc 100644
@@ -140,7 +140,7 @@ static int tc_qdisc_modify(int cmd, unsigned int flags, int argc, char **argv)
 
 	if (q) {
 		if (q->parse_qopt) {
-			if (q->parse_qopt(q, argc, argv, &req.n))
+			if (q->parse_qopt(q, argc, argv, &req.n, d))
 				return 1;
 		} else if (argc) {
 			fprintf(stderr, "qdisc '%s' does not support option parsing\n", k);
tc/tc_util.c +66 -0

72 lines not on this page · raw message

tc/tc_util.h +6 -2
index 583a21a..e79b44e 100644
@@ -24,14 +24,14 @@ struct qdisc_util {
 	struct  qdisc_util *next;
 	const char *id;
 	int (*parse_qopt)(struct qdisc_util *qu, int argc,
-			  char **argv, struct nlmsghdr *n);
+			  char **argv, struct nlmsghdr *n, char *dev);
 	int (*print_qopt)(struct qdisc_util *qu,
 			  FILE *f, struct rtattr *opt);
 	int (*print_xstats)(struct qdisc_util *qu,
 			    FILE *f, struct rtattr *xstats);
 
 	int (*parse_copt)(struct qdisc_util *qu, int argc,
-			  char **argv, struct nlmsghdr *n);
+			  char **argv, struct nlmsghdr *n, char *dev);
 	int (*print_copt)(struct qdisc_util *qu, FILE *f, struct rtattr *opt);
 };
 

@@ -66,9 +66,13 @@ const char *get_tc_lib(void);
 struct qdisc_util *get_qdisc_kind(const char *str);
 struct filter_util *get_filter_kind(const char *str);
 
+int read_prop(char *dev, char *prop, long *value);
+int parse_percent_rate(char *rate, const char *str, char *dev);
 int get_qdisc_handle(__u32 *h, const char *str);
 int get_rate(unsigned int *rate, const char *str);
+int get_percent_rate(unsigned int *rate, const char *str, char *dev);
 int get_rate64(__u64 *rate, const char *str);
+int get_percent_rate64(__u64 *rate, const char *str, char *dev);
 int get_size(unsigned int *size, const char *str);
 int get_size_and_cell(unsigned int *size, int *cell_log, char *str);
 int get_time(unsigned int *time, const char *str);
Signature · 1 line
1.9.1
#1 lore raw
Quoted 14 lines · Nishanth Devarajan

This patch adapts the tc command line interface to allow bandwidth limits to be specified as a percentage of the interface's capacity.

For this purpose, we've modified and moved int read_prop() from ip/iptuntap.c to lib.utils.c to make it accessible to tc.

Additionally, adding this functionality requires passing the specified device string to each class/qdisc which changes the prototype for a couple of functions: the .parse_qopt and .parse_copt interfaces. The device string is a required parameter for tc-qdisc and tc-class, and when not specified, the kernel returns ENODEV. In this patch, if the user tries to specify a bandwidth percentage without naming the device, we return an error from userspace.

Quoted 1 line

Signed-off by: Nishanth Devarajan <[email protected]>

IMHO you need to at least add a big warning in the man page that the per cent speed means the fraction of *current* speed, and if the speed changes the value will not be recalculated.

#2 lore raw
In reply to Nishanth Devarajan
Quoted 1 line · On Wed, 15 Nov 2017 07:06:21 +0530 Nishanth Devarajan <[email protected]>…

int parse_percent_rate(char *rate, const char *str, char *dev)

You aren't modifyin dev so it should be const char *

tc/tc_util.c static const struct rate_suffix { · line 206

Quoted 13 lines
tc/tc_util.c +13 -0
+{
+	long max_rate_bits;
+	int ret, saved_errno;
+	double perc, rate_bits;
+	char *str_perc, *p;
+
+	if (!dev[0]) {
+		fprintf(stderr, "No device specified; specify device to rate limit by percentage\n");
+		return -1;
+	}
+
+	if (read_prop(dev, "speed", &max_rate_bits))
+		return -1;

If speed is unknown, then many will devices will return -1. You need to handle that.

Since speed reported by kernel is in mbits per second, it would make sense to rename max_rate_bits to mbit.

tc/tc_util.c static const struct rate_suffix { · line 215

Quoted 9 lines
tc/tc_util.c +9 -0
+
+	ret = sscanf(str, "%m[0-9.%]", &str_perc);
+	if (ret != 1)
+		goto malf;
+
+	/* Make sure there's only one percent sign and it's at the end */
+	perc = strtod(str_perc, &p);
+	if (*p != '%' || *(p++) != '\0')
+		goto malf;

There already is parse_percent in tc/q_netem.c. Please move that to util and use that instead of coding here.

Quoted 23 lines
tc/tc_util.c +23 -0
+
+	saved_errno = errno;
+	free(str_perc);
+
+	if (perc > 100.0 || perc < 0.0 || saved_errno == ERANGE) {
+		fprintf(stderr, "Invalid rate specified; should be between [0,100]%% but is %s\n", str);
+		return -1;
+	}
+
+	rate_bits = (perc * max_rate_bits) / 100.0;
+
+	ret = snprintf(rate, 20, "%lf", rate_bits);
+	if (ret <= 0 || ret >= 20) {
+		fprintf(stderr, "Unable to parse calculated rate\n");
+		return -1;
+	}
+
+	return 0;
+
+malf:
+	fprintf(stderr, "Specified rate value could not be read or is malformed\n");
+	return -1;
+}