tc/f_flow.c

/*
 * f_flow.c		Flow filter
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Authors:	Patrick McHardy <kaber@trash.net>
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

#include "utils.h"
#include "tc_util.h"
#include "m_ematch.h"

static void explain(void)
{
	fprintf(stderr,
"Usage: ... flow ...\n"
"\n"
" [mapping mode]: map key KEY [ OPS ] ...\n"
" [hashing mode]: hash keys KEY-LIST ... [ perturb SECS ]\n"
"\n"
"                 [ divisor NUM ] [ baseclass ID ] [ match EMATCH_TREE ]\n"
"                 [ action ACTION_SPEC ]\n"
"\n"
"KEY-LIST := [ KEY-LIST , ] KEY\n"
"KEY      := [ src | dst | proto | proto-src | proto-dst | iif | priority |\n"
"              mark | nfct | nfct-src | nfct-dst | nfct-proto-src |\n"
"              nfct-proto-dst | rt-classid | sk-uid | sk-gid |\n"
"              vlan-tag | rxhash ]\n"
"OPS      := [ or NUM | and NUM | xor NUM | rshift NUM | addend NUM ]\n"
"ID       := X:Y\n"
	);
}

static const char *flow_keys[FLOW_KEY_MAX+1] = {
	[FLOW_KEY_SRC]			= "src",
	[FLOW_KEY_DST]			= "dst",
	[FLOW_KEY_PROTO]		= "proto",
	[FLOW_KEY_PROTO_SRC]		= "proto-src",
	[FLOW_KEY_PROTO_DST]		= "proto-dst",
	[FLOW_KEY_IIF]			= "iif",
	[FLOW_KEY_PRIORITY]		= "priority",
	[FLOW_KEY_MARK]			= "mark",
	[FLOW_KEY_NFCT]			= "nfct",
	[FLOW_KEY_NFCT_SRC]		= "nfct-src",
	[FLOW_KEY_NFCT_DST]		= "nfct-dst",
	[FLOW_KEY_NFCT_PROTO_SRC]	= "nfct-proto-src",
	[FLOW_KEY_NFCT_PROTO_DST]	= "nfct-proto-dst",
	[FLOW_KEY_RTCLASSID]		= "rt-classid",
	[FLOW_KEY_SKUID]		= "sk-uid",
	[FLOW_KEY_SKGID]		= "sk-gid",
	[FLOW_KEY_VLAN_TAG]		= "vlan-tag",
	[FLOW_KEY_RXHASH]		= "rxhash",
};

static int flow_parse_keys(__u32 *keys, __u32 *nkeys, char *argv)
{
	char *s, *sep;
	unsigned int i;

	*keys = 0;
	*nkeys = 0;
	s = argv;
	while (s != NULL) {
		sep = strchr(s, ',');
		if (sep)
			*sep = '\0';

		for (i = 0; i <= FLOW_KEY_MAX; i++) {
			if (matches(s, flow_keys[i]) == 0) {
				*keys |= 1 << i;
				(*nkeys)++;
				break;
			}
		}
		if (i > FLOW_KEY_MAX) {
			fprintf(stderr, "Unknown flow key \"%s\"\n", s);
			return -1;
		}
		s = sep ? sep + 1 : NULL;
	}
	return 0;
}

static void transfer_bitop(__u32 *mask, __u32 *xor, __u32 m, __u32 x)
{
	*xor = x ^ (*xor & m);
	*mask &= m;
}

static int get_addend(__u32 *addend, char *argv, __u32 keys)
{
	inet_prefix addr;
	int sign = 0;
	__u32 tmp;

	if (*argv == '-') {
		sign = 1;
		argv++;
	}

	if (get_u32(&tmp, argv, 0) == 0)
		goto out;

	if (keys & (FLOW_KEY_SRC | FLOW_KEY_DST |
		    FLOW_KEY_NFCT_SRC | FLOW_KEY_NFCT_DST) &&
	    get_addr(&addr, argv, AF_UNSPEC) == 0) {
		switch (addr.family) {
		case AF_INET:
			tmp = ntohl(addr.data[0]);
			goto out;
		case AF_INET6:
			tmp = ntohl(addr.data[3]);
			goto out;
		}
	}

	return -1;
out:
	if (sign)
		tmp = -tmp;
	*addend = tmp;
	return 0;
}

static int flow_parse_opt(struct filter_util *fu, char *handle,
			  int argc, char **argv, struct nlmsghdr *n)
{
	struct tc_police tp;
	struct tcmsg *t = NLMSG_DATA(n);
	struct rtattr *tail;
	__u32 mask = ~0U, xor = 0;
	__u32 keys = 0, nkeys = 0;
	__u32 mode = FLOW_MODE_MAP;
	__u32 tmp;

	memset(&tp, 0, sizeof(tp));

	if (handle) {
		if (get_u32(&t->tcm_handle, handle, 0)) {
			fprintf(stderr, "Illegal \"handle\"\n");
			return -1;
		}
	}

	tail = NLMSG_TAIL(n);
	addattr_l(n, 4096, TCA_OPTIONS, NULL, 0);

	while (argc > 0) {
		if (matches(*argv, "map") == 0) {
			mode = FLOW_MODE_MAP;
		} else if (matches(*argv, "hash") == 0) {
			mode = FLOW_MODE_HASH;
		} else if (matches(*argv, "keys") == 0) {
			NEXT_ARG();
			if (flow_parse_keys(&keys, &nkeys, *argv))
				return -1;
			addattr32(n, 4096, TCA_FLOW_KEYS, keys);
		} else if (matches(*argv, "and") == 0) {
			NEXT_ARG();
			if (get_u32(&tmp, *argv, 0)) {
				fprintf(stderr, "Illegal \"mask\"\n");
				return -1;
			}
			transfer_bitop(&mask, &xor, tmp, 0);
		} else if (matches(*argv, "or") == 0) {
			NEXT_ARG();
			if (get_u32(&tmp, *argv, 0)) {
				fprintf(stderr, "Illegal \"or\"\n");
				return -1;
			}
			transfer_bitop(&mask, &xor, ~tmp, tmp);
		} else if (matches(*argv, "xor") == 0) {
			NEXT_ARG();
			if (get_u32(&tmp, *argv, 0)) {
				fprintf(stderr, "Illegal \"xor\"\n");
				return -1;
			}
			transfer_bitop(&mask, &xor, ~0, tmp);
		} else if (matches(*argv, "rshift") == 0) {
			NEXT_ARG();
			if (get_u32(&tmp, *argv, 0)) {
				fprintf(stderr, "Illegal \"rshift\"\n");
				return -1;
			}
			addattr32(n, 4096, TCA_FLOW_RSHIFT, tmp);
		} else if (matches(*argv, "addend") == 0) {
			NEXT_ARG();
			if (get_addend(&tmp, *argv, keys)) {
				fprintf(stderr, "Illegal \"addend\"\n");
				return -1;
			}
			addattr32(n, 4096, TCA_FLOW_ADDEND, tmp);
		} else if (matches(*argv, "divisor") == 0) {
			NEXT_ARG();
			if (get_u32(&tmp, *argv, 0)) {
				fprintf(stderr, "Illegal \"divisor\"\n");
				return -1;
			}
			addattr32(n, 4096, TCA_FLOW_DIVISOR, tmp);
		} else if (matches(*argv, "baseclass") == 0) {
			NEXT_ARG();
			if (get_tc_classid(&tmp, *argv) || TC_H_MIN(tmp) == 0) {
				fprintf(stderr, "Illegal \"baseclass\"\n");
				return -1;
			}
			addattr32(n, 4096, TCA_FLOW_BASECLASS, tmp);
		} else if (matches(*argv, "perturb") == 0) {
			NEXT_ARG();
			if (get_u32(&tmp, *argv, 0)) {
				fprintf(stderr, "Illegal \"perturb\"\n");
				return -1;
			}
			addattr32(n, 4096, TCA_FLOW_PERTURB, tmp);
		} else if (matches(*argv, "police") == 0) {
			NEXT_ARG();
			if (parse_police(&argc, &argv, TCA_FLOW_POLICE, n)) {
				fprintf(stderr, "Illegal \"police\"\n");
				return -1;
			}
			continue;
		} else if (matches(*argv, "action") == 0) {
			NEXT_ARG();
			if (parse_action(&argc, &argv, TCA_FLOW_ACT, n)) {
				fprintf(stderr, "Illegal \"action\"\n");
				return -1;
			}
			continue;
		} else if (matches(*argv, "match") == 0) {
			NEXT_ARG();
			if (parse_ematch(&argc, &argv, TCA_FLOW_EMATCHES, n)) {
				fprintf(stderr, "Illegal \"ematch\"\n");
				return -1;
			}
			continue;
		} else if (matches(*argv, "help") == 0) {
			explain();
			return -1;
		} else {
			fprintf(stderr, "What is \"%s\"?\n", *argv);
			explain();
			return -1;
		}
		argv++, argc--;
	}

	if (nkeys > 1 && mode != FLOW_MODE_HASH) {
		fprintf(stderr, "Invalid mode \"map\" for multiple keys\n");
		return -1;
	}
	addattr32(n, 4096, TCA_FLOW_MODE, mode);

	if (mask != ~0 || xor != 0) {
		addattr32(n, 4096, TCA_FLOW_MASK, mask);
		addattr32(n, 4096, TCA_FLOW_XOR, xor);
	}

	tail->rta_len = (void *)NLMSG_TAIL(n) - (void *)tail;
	return 0;
}

static int flow_print_opt(struct filter_util *fu, FILE *f, struct rtattr *opt,
			  __u32 handle)
{
	struct rtattr *tb[TCA_FLOW_MAX+1];

	SPRINT_BUF(b1);
	unsigned int i;
	__u32 mask = ~0, val = 0;

	if (opt == NULL)
		return -EINVAL;

	parse_rtattr_nested(tb, TCA_FLOW_MAX, opt);

	fprintf(f, "handle 0x%x ", handle);

	if (tb[TCA_FLOW_MODE]) {
		__u32 mode = rta_getattr_u32(tb[TCA_FLOW_MODE]);

		switch (mode) {
		case FLOW_MODE_MAP:
			fprintf(f, "map ");
			break;
		case FLOW_MODE_HASH:
			fprintf(f, "hash ");
			break;
		}
	}

	if (tb[TCA_FLOW_KEYS]) {
		__u32 keymask = rta_getattr_u32(tb[TCA_FLOW_KEYS]);
		char *sep = "";

		fprintf(f, "keys ");
		for (i = 0; i <= FLOW_KEY_MAX; i++) {
			if (keymask & (1 << i)) {
				fprintf(f, "%s%s", sep, flow_keys[i]);
				sep = ",";
			}
		}
		fprintf(f, " ");
	}

	if (tb[TCA_FLOW_MASK])
		mask = rta_getattr_u32(tb[TCA_FLOW_MASK]);
	if (tb[TCA_FLOW_XOR])
		val = rta_getattr_u32(tb[TCA_FLOW_XOR]);

	if (mask != ~0 || val != 0) {
		__u32 or = (mask & val) ^ val;
		__u32 xor = mask & val;

		if (mask != ~0)
			fprintf(f, "and 0x%.8x ", mask);
		if (xor != 0)
			fprintf(f, "xor 0x%.8x ", xor);
		if (or != 0)
			fprintf(f, "or 0x%.8x ", or);
	}

	if (tb[TCA_FLOW_RSHIFT])
		fprintf(f, "rshift %u ",
			rta_getattr_u32(tb[TCA_FLOW_RSHIFT]));
	if (tb[TCA_FLOW_ADDEND])
		fprintf(f, "addend 0x%x ",
			rta_getattr_u32(tb[TCA_FLOW_ADDEND]));

	if (tb[TCA_FLOW_DIVISOR])
		fprintf(f, "divisor %u ",
			rta_getattr_u32(tb[TCA_FLOW_DIVISOR]));
	if (tb[TCA_FLOW_BASECLASS])
		fprintf(f, "baseclass %s ",
			sprint_tc_classid(rta_getattr_u32(tb[TCA_FLOW_BASECLASS]), b1));

	if (tb[TCA_FLOW_PERTURB])
		fprintf(f, "perturb %usec ",
			rta_getattr_u32(tb[TCA_FLOW_PERTURB]));

	if (tb[TCA_FLOW_EMATCHES])
		print_ematch(f, tb[TCA_FLOW_EMATCHES]);
	if (tb[TCA_FLOW_POLICE])
		tc_print_police(f, tb[TCA_FLOW_POLICE]);
	if (tb[TCA_FLOW_ACT]) {
		fprintf(f, "\n");
		tc_print_action(f, tb[TCA_FLOW_ACT]);
	}
	return 0;
}

struct filter_util flow_filter_util = {
	.id		= "flow",
	.parse_fopt	= flow_parse_opt,
	.print_fopt	= flow_print_opt,
};