diff options
Diffstat (limited to 'extensions/libipt_TCPMSS.c')
| -rw-r--r-- | extensions/libipt_TCPMSS.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/extensions/libipt_TCPMSS.c b/extensions/libipt_TCPMSS.c index db8757b7..03ce1bdb 100644 --- a/extensions/libipt_TCPMSS.c +++ b/extensions/libipt_TCPMSS.c @@ -21,13 +21,15 @@ static void help(void) { printf( -"TCPMSS target v%s options:\n" -" --set-mss value Value to set MSS option to\n", +"TCPMSS target v%s mutually-exclusive options:\n" +" --set-mss value explicitly set MSS option to specified value\n" +" --clamp-mss-to-pmtu automatically clamp MSS value to (path_MTU - 40)\n", NETFILTER_VERSION); } static struct option opts[] = { { "set-mss", 1, 0, '1' }, + { "clamp-mss-to-pmtu", 0, 0, '2' }, { 0 } }; @@ -53,14 +55,22 @@ parse(int c, char **argv, int invert, unsigned int *flags, 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) + "TCPMSS target: Only one option may be specified"); + if ((mssval = string_to_number(optarg, 0, 65535 - 40)) == -1) exit_error(PARAMETER_PROBLEM, "Bad TCPMSS value `%s'", optarg); mssinfo->mss = mssval; *flags = 1; break; + case '2': + if (*flags) + exit_error(PARAMETER_PROBLEM, + "TCPMSS target: Only one option may be specified"); + mssinfo->mss = IPT_TCPMSS_CLAMP_PMTU; + *flags = 1; + break; + default: return 0; } @@ -73,7 +83,7 @@ final_check(unsigned int flags) { if (!flags) exit_error(PARAMETER_PROBLEM, - "TCPMSS target: Parameter --set-mss is required"); + "TCPMSS target: At least one parameter is required"); } /* Prints out the targinfo. */ @@ -84,7 +94,10 @@ print(const struct ipt_ip *ip, { const struct ipt_tcpmss_info *mssinfo = (const struct ipt_tcpmss_info *)target->data; - printf("TCPMSS set %u ", mssinfo->mss); + if(mssinfo->mss == IPT_TCPMSS_CLAMP_PMTU) + printf("TCPMSS clamp to PMTU "); + else + printf("TCPMSS set %u ", mssinfo->mss); } /* Saves the union ipt_targinfo in parsable form to stdout. */ @@ -94,7 +107,10 @@ 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); + if(mssinfo->mss == IPT_TCPMSS_CLAMP_PMTU) + printf("--clamp-mss-to-pmtu "); + else + printf("--set-mss %u ", mssinfo->mss); } struct iptables_target mss |