From acef6043f647806096c41294b00472f6ce7462d7 Mon Sep 17 00:00:00 2001 From: Jan Engelhardt Date: Mon, 7 Feb 2011 03:18:53 +0100 Subject: src: deduplicate and simplify implicit protocol extension loading Signed-off-by: Jan Engelhardt --- xshared.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) (limited to 'xshared.c') diff --git a/xshared.c b/xshared.c index 40b6b560..b47beb1e 100644 --- a/xshared.c +++ b/xshared.c @@ -1,4 +1,5 @@ #include +#include #include #include #include @@ -50,7 +51,7 @@ proto_to_name(uint8_t proto, int nolookup) return NULL; } -struct xtables_match * +static struct xtables_match * find_proto(const char *pname, enum xtables_tryload tryload, int nolookup, struct xtables_rule_match **matches) { @@ -66,3 +67,35 @@ find_proto(const char *pname, enum xtables_tryload tryload, return NULL; } + +/* + * Some explanations (after four different bugs in 3 different releases): If + * we encounter a parameter, that has not been parsed yet, it's not an option + * of an explicitly loaded match or a target. However, we support implicit + * loading of the protocol match extension. '-p tcp' means 'l4 proto 6' and at + * the same time 'load tcp protocol match on demand if we specify --dport'. + * + * To make this work, we need to make sure: + * - the parameter has not been parsed by a match (m above) + * - a protocol has been specified + * - the protocol extension has not been loaded yet, or is loaded and unused + * [think of ip6tables-restore!] + * - the protocol extension can be successively loaded + */ +static bool should_load_proto(struct iptables_command_state *cs) +{ + if (cs->protocol == NULL) + return false; + if (find_proto(cs->protocol, XTF_DONT_LOAD, + cs->options & OPT_NUMERIC, NULL) != NULL) + return true; + return cs->proto_used; +} + +struct xtables_match *load_proto(struct iptables_command_state *cs) +{ + if (!should_load_proto(cs)) + return NULL; + return find_proto(cs->protocol, XTF_TRY_LOAD, + cs->options & OPT_NUMERIC, &cs->matches); +} -- cgit v1.2.3