From 5e8f64f46cb1dd71b0a94cb7dad87da00b8c5e32 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 15 May 2012 01:51:29 +0200 Subject: conntrackd: add cthelper infrastructure (+ example FTP helper) This patch adds the user-space helper infrastructure. It also contains the implementation of the FTP helper in user-space. There's one example file that you can use to configure conntrackd as user-space connection tracking helper under: doc/helper/conntrackd.conf Signed-off-by: Pablo Neira Ayuso --- src/read_config_yy.y | 200 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) (limited to 'src/read_config_yy.y') diff --git a/src/read_config_yy.y b/src/read_config_yy.y index b22784c..c9235d3 100644 --- a/src/read_config_yy.y +++ b/src/read_config_yy.y @@ -28,8 +28,11 @@ #include "conntrackd.h" #include "bitops.h" #include "cidr.h" +#include "helper.h" +#include "stack.h" #include #include +#include #include #include @@ -48,6 +51,15 @@ static void print_err(int err, const char *msg, ...); static void __kernel_filter_start(void); static void __kernel_filter_add_state(int value); static void __max_dedicated_links_reached(void); + +struct stack symbol_stack; + +enum { + SYMBOL_HELPER_QUEUE_NUM, + SYMBOL_HELPER_POLICY_EXPECT_ROOT, + SYMBOL_HELPER_EXPECT_POLICY_LEAF, +}; + %} %union { @@ -74,6 +86,8 @@ static void __max_dedicated_links_reached(void); %token T_SCHEDULER T_TYPE T_PRIO T_NETLINK_EVENTS_RELIABLE %token T_DISABLE_INTERNAL_CACHE T_DISABLE_EXTERNAL_CACHE T_ERROR_QUEUE_LENGTH %token T_OPTIONS T_TCP_WINDOW_TRACKING T_EXPECT_SYNC +%token T_HELPER T_HELPER_QUEUE_NUM T_HELPER_POLICY T_HELPER_EXPECT_MAX +%token T_HELPER_EXPECT_TIMEOUT %token T_IP T_PATH_VAL %token T_NUMBER @@ -96,6 +110,7 @@ line : ignore_protocol | general | sync | stats + | helper ; logfile_bool : T_LOG T_ON @@ -1561,6 +1576,186 @@ buffer_size: T_STAT_BUFFER_SIZE T_NUMBER print_err(CTD_CFG_WARN, "`LogFileBufferSize' is deprecated"); }; +helper: T_HELPER '{' helper_list '}' +{ + conf.flags |= CTD_HELPER; +}; + +helper_list: + | helper_list helper_line + ; + +helper_line: helper_type + ; + +helper_type: T_TYPE T_STRING T_STRING T_STRING '{' helper_type_list '}' +{ + struct ctd_helper_instance *helper_inst; + struct ctd_helper *helper; + struct stack_item *e; + uint16_t l3proto; + uint8_t l4proto; + + if (strcmp($3, "inet") == 0) + l3proto = AF_INET; + else if (strcmp($3, "inet6") == 0) + l3proto = AF_INET6; + else { + print_err(CTD_CFG_ERROR, "unknown layer 3 protocol"); + exit(EXIT_FAILURE); + } + + if (strcmp($4, "tcp") == 0) + l4proto = IPPROTO_TCP; + else if (strcmp($4, "udp") == 0) + l4proto = IPPROTO_UDP; + else { + print_err(CTD_CFG_ERROR, "unknown layer 4 protocol"); + exit(EXIT_FAILURE); + } + + /* XXX use configure.ac definitions. */ + helper = helper_find("/usr/lib/conntrack-tools", $2, l4proto, RTLD_NOW); + if (helper == NULL) { + print_err(CTD_CFG_ERROR, "Unknown `%s' helper", $2); + exit(EXIT_FAILURE); + } + + helper_inst = calloc(1, sizeof(struct ctd_helper_instance)); + if (helper_inst == NULL) + break; + + helper_inst->l3proto = l3proto; + helper_inst->l4proto = l4proto; + helper_inst->helper = helper; + + while ((e = stack_item_pop(&symbol_stack, -1)) != NULL) { + + switch(e->type) { + case SYMBOL_HELPER_QUEUE_NUM: { + int *qnum = (int *) &e->data; + + helper_inst->queue_num = *qnum; + stack_item_free(e); + break; + } + case SYMBOL_HELPER_POLICY_EXPECT_ROOT: { + struct ctd_helper_policy *pol = + (struct ctd_helper_policy *) &e->data; + struct ctd_helper_policy *matching = NULL; + int i; + + for (i=0; ipolicy[i].name, + pol->name) != 0) + continue; + + matching = pol; + break; + } + if (matching == NULL) { + print_err(CTD_CFG_ERROR, + "Unknown policy `%s' in helper " + "configuration", pol->name); + exit(EXIT_FAILURE); + } + /* FIXME: First set default policy, then change only + * tuned fields, not everything. + */ + memcpy(&helper->policy[i], pol, + sizeof(struct ctd_helper_policy)); + + stack_item_free(e); + break; + } + default: + print_err(CTD_CFG_ERROR, + "Unexpected symbol parsing helper policy"); + exit(EXIT_FAILURE); + break; + } + } + list_add(&helper_inst->head, &CONFIG(cthelper).list); +}; + +helper_type_list: + | helper_type_list helper_type_line + ; + +helper_type_line: helper_type + ; + +helper_type: T_HELPER_QUEUE_NUM T_NUMBER +{ + int *qnum; + struct stack_item *e; + + e = stack_item_alloc(SYMBOL_HELPER_QUEUE_NUM, sizeof(int)); + qnum = (int *) e->data; + *qnum = $2; + stack_item_push(&symbol_stack, e); +}; + +helper_type: T_HELPER_POLICY T_STRING '{' helper_policy_list '}' +{ + struct stack_item *e; + struct ctd_helper_policy *policy; + + e = stack_item_pop(&symbol_stack, SYMBOL_HELPER_EXPECT_POLICY_LEAF); + if (e == NULL) { + print_err(CTD_CFG_ERROR, + "Helper policy configuration empty, fix your " + "configuration file, please"); + exit(EXIT_FAILURE); + break; + } + + policy = (struct ctd_helper_policy *) &e->data; + strncpy(policy->name, $2, CTD_HELPER_NAME_LEN); + policy->name[CTD_HELPER_NAME_LEN-1] = '\0'; + /* Now object is complete. */ + e->type = SYMBOL_HELPER_POLICY_EXPECT_ROOT; + stack_item_push(&symbol_stack, e); +}; + +helper_policy_list: + | helper_policy_list helper_policy_line + ; + +helper_policy_line: helper_policy_expect_max + | helper_policy_expect_timeout + ; + +helper_policy_expect_max: T_HELPER_EXPECT_MAX T_NUMBER +{ + struct stack_item *e; + struct ctd_helper_policy *policy; + + e = stack_item_pop(&symbol_stack, SYMBOL_HELPER_EXPECT_POLICY_LEAF); + if (e == NULL) { + e = stack_item_alloc(SYMBOL_HELPER_EXPECT_POLICY_LEAF, + sizeof(struct ctd_helper_policy)); + } + policy = (struct ctd_helper_policy *) &e->data; + policy->expect_max = $2; + stack_item_push(&symbol_stack, e); +}; + +helper_policy_expect_timeout: T_HELPER_EXPECT_TIMEOUT T_NUMBER +{ + struct stack_item *e; + struct ctd_helper_policy *policy; + + e = stack_item_pop(&symbol_stack, SYMBOL_HELPER_EXPECT_POLICY_LEAF); + if (e == NULL) { + e = stack_item_alloc(SYMBOL_HELPER_EXPECT_POLICY_LEAF, + sizeof(struct ctd_helper_policy)); + } + policy = (struct ctd_helper_policy *) &e->data; + policy->expect_timeout = $2; + stack_item_push(&symbol_stack, e); +}; + %% int __attribute__((noreturn)) @@ -1640,6 +1835,11 @@ init_config(char *filename) CONFIG(stats).syslog_facility = -1; CONFIG(netlink).subsys_id = -1; + /* Initialize list of user-space helpers */ + INIT_LIST_HEAD(&CONFIG(cthelper).list); + + stack_init(&symbol_stack); + yyrestart(fp); yyparse(); fclose(fp); -- cgit v1.2.3