diff options
Diffstat (limited to 'extensions')
-rw-r--r-- | extensions/libipt_TCPMSS.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/extensions/libipt_TCPMSS.c b/extensions/libipt_TCPMSS.c new file mode 100644 index 00000000..db8757b7 --- /dev/null +++ b/extensions/libipt_TCPMSS.c @@ -0,0 +1,118 @@ +/* Shared library add-on to iptables to add TCPMSS target support. + * + * Copyright (c) 2000 Marc Boucher +*/ +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <getopt.h> + +#include <iptables.h> +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv4/ipt_TCPMSS.h> + +struct mssinfo { + struct ipt_entry_target t; + struct ipt_tcpmss_info mss; +}; + +/* Function which prints out usage message. */ +static void +help(void) +{ + printf( +"TCPMSS target v%s options:\n" +" --set-mss value Value to set MSS option to\n", +NETFILTER_VERSION); +} + +static struct option opts[] = { + { "set-mss", 1, 0, '1' }, + { 0 } +}; + +/* Initialize the target. */ +static void +init(struct ipt_entry_target *t, unsigned int *nfcache) +{ +} + +/* Function which parses command options; returns true if it + ate an option */ +static int +parse(int c, char **argv, int invert, unsigned int *flags, + const struct ipt_entry *entry, + struct ipt_entry_target **target) +{ + struct ipt_tcpmss_info *mssinfo + = (struct ipt_tcpmss_info *)(*target)->data; + + switch (c) { + int mssval; + + case '1': + if (*flags) + exit_error(PARAMETER_PROBLEM, + "TCPMSS target: Can't specify --set-mss twice"); + if ((mssval = string_to_number(optarg, 0, 65535)) == -1) + exit_error(PARAMETER_PROBLEM, "Bad TCPMSS value `%s'", optarg); + + mssinfo->mss = mssval; + *flags = 1; + break; + + default: + return 0; + } + + return 1; +} + +static void +final_check(unsigned int flags) +{ + if (!flags) + exit_error(PARAMETER_PROBLEM, + "TCPMSS target: Parameter --set-mss is required"); +} + +/* Prints out the targinfo. */ +static void +print(const struct ipt_ip *ip, + const struct ipt_entry_target *target, + int numeric) +{ + const struct ipt_tcpmss_info *mssinfo = + (const struct ipt_tcpmss_info *)target->data; + printf("TCPMSS set %u ", mssinfo->mss); +} + +/* Saves the union ipt_targinfo in parsable form to stdout. */ +static void +save(const struct ipt_ip *ip, const struct ipt_entry_target *target) +{ + const struct ipt_tcpmss_info *mssinfo = + (const struct ipt_tcpmss_info *)target->data; + + printf("--set-mss %u ", mssinfo->mss); +} + +struct iptables_target mss += { NULL, + "TCPMSS", + NETFILTER_VERSION, + IPT_ALIGN(sizeof(struct ipt_tcpmss_info)), + IPT_ALIGN(sizeof(struct ipt_tcpmss_info)), + &help, + &init, + &parse, + &final_check, + &print, + &save, + opts +}; + +void _init(void) +{ + register_target(&mss); +} |