From af72a05656c7524febb52ffe2c7eed6ccf1f84ee Mon Sep 17 00:00:00 2001 From: Arturo Borrero Date: Wed, 4 Mar 2015 19:49:02 +0100 Subject: ebtables-compat: add support for limit extension Add support for the ebtables limit extension (match), Signed-off-by: Arturo Borrero Gonzalez --- extensions/libebt_limit.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 179 insertions(+) create mode 100644 extensions/libebt_limit.c (limited to 'extensions') diff --git a/extensions/libebt_limit.c b/extensions/libebt_limit.c new file mode 100644 index 00000000..c71561c1 --- /dev/null +++ b/extensions/libebt_limit.c @@ -0,0 +1,179 @@ +/* ebt_limit + * + * Authors: + * Tom Marshall + * + * Mostly copied from iptables' limit match. + * + * September, 2003 + * + * Translated to use libxtables for ebtables-compat in 2015 by + * Arturo Borrero Gonzalez + */ + +#include +#include +#include +#include +#include +#include +#include +#include "iptables/nft.h" +#include "iptables/nft-bridge.h" + +#define EBT_LIMIT_AVG "3/hour" +#define EBT_LIMIT_BURST 5 + +#define FLAG_LIMIT 0x01 +#define FLAG_LIMIT_BURST 0x02 +#define ARG_LIMIT '1' +#define ARG_LIMIT_BURST '2' + +static struct option brlimit_opts[] = +{ + { .name = "limit", .has_arg = true, .val = ARG_LIMIT }, + { .name = "limit-burst",.has_arg = true, .val = ARG_LIMIT_BURST }, + XT_GETOPT_TABLEEND, +}; + +static void brlimit_print_help(void) +{ + printf( +"limit options:\n" +"--limit avg : max average match rate: default "EBT_LIMIT_AVG"\n" +" [Packets per second unless followed by \n" +" /sec /minute /hour /day postfixes]\n" +"--limit-burst number : number to match in a burst, -1 < number < 10001,\n" +" default %u\n", EBT_LIMIT_BURST); +} + +static int parse_rate(const char *rate, uint32_t *val) +{ + const char *delim; + uint32_t r; + uint32_t mult = 1; /* Seconds by default. */ + + delim = strchr(rate, '/'); + if (delim) { + if (strlen(delim+1) == 0) + return 0; + + if (strncasecmp(delim+1, "second", strlen(delim+1)) == 0) + mult = 1; + else if (strncasecmp(delim+1, "minute", strlen(delim+1)) == 0) + mult = 60; + else if (strncasecmp(delim+1, "hour", strlen(delim+1)) == 0) + mult = 60*60; + else if (strncasecmp(delim+1, "day", strlen(delim+1)) == 0) + mult = 24*60*60; + else + return 0; + } + r = atoi(rate); + if (!r) + return 0; + + /* This would get mapped to infinite (1/day is minimum they + can specify, so we're ok at that end). */ + if (r / mult > EBT_LIMIT_SCALE) + return 0; + + *val = EBT_LIMIT_SCALE * mult / r; + return 1; +} + +static void brlimit_init(struct xt_entry_match *match) +{ + struct ebt_limit_info *r = (struct ebt_limit_info *)match->data; + + parse_rate(EBT_LIMIT_AVG, &r->avg); + r->burst = EBT_LIMIT_BURST; +} + +static int brlimit_parse(int c, char **argv, int invert, unsigned int *flags, + const void *entry, struct xt_entry_match **match) +{ + struct ebt_limit_info *r = (struct ebt_limit_info *)(*match)->data; + uintmax_t num; + + switch (c) { + case ARG_LIMIT: + EBT_CHECK_OPTION(flags, FLAG_LIMIT); + if (invert) + xtables_error(PARAMETER_PROBLEM, + "Unexpected `!' after --limit"); + if (!parse_rate(optarg, &r->avg)) + xtables_error(PARAMETER_PROBLEM, + "bad rate `%s'", optarg); + break; + case ARG_LIMIT_BURST: + EBT_CHECK_OPTION(flags, FLAG_LIMIT_BURST); + if (invert) + xtables_error(PARAMETER_PROBLEM, + "Unexpected `!' after --limit-burst"); + if (!xtables_strtoul(optarg, NULL, &num, 0, 10000)) + xtables_error(PARAMETER_PROBLEM, + "bad --limit-burst `%s'", optarg); + r->burst = num; + break; + default: + return 0; + } + + return 1; +} + +struct rates +{ + const char *name; + uint32_t mult; +}; + +static struct rates g_rates[] = +{ + { "day", EBT_LIMIT_SCALE*24*60*60 }, + { "hour", EBT_LIMIT_SCALE*60*60 }, + { "min", EBT_LIMIT_SCALE*60 }, + { "sec", EBT_LIMIT_SCALE } +}; + +static void print_rate(uint32_t period) +{ + unsigned int i; + + for (i = 1; i < sizeof(g_rates)/sizeof(struct rates); i++) + if (period > g_rates[i].mult || + g_rates[i].mult/period < g_rates[i].mult%period) + break; + + printf("%u/%s ", g_rates[i-1].mult / period, g_rates[i-1].name); +} + +static void brlimit_print(const void *ip, const struct xt_entry_match *match, + int numeric) +{ + struct ebt_limit_info *r = (struct ebt_limit_info *)match->data; + + printf("--limit "); + print_rate(r->avg); + printf("--limit-burst %u ", r->burst); +} + +static struct xtables_match brlimit_match = { + .name = "limit", + .revision = 0, + .version = XTABLES_VERSION, + .family = NFPROTO_BRIDGE, + .size = XT_ALIGN(sizeof(struct ebt_limit_info)), + .userspacesize = offsetof(struct ebt_limit_info, prev), + .init = brlimit_init, + .help = brlimit_print_help, + .parse = brlimit_parse, + .print = brlimit_print, + .extra_opts = brlimit_opts, +}; + +void _init(void) +{ + xtables_register_match(&brlimit_match); +} -- cgit v1.2.3