1 files changed, 544 insertions, 3 deletions

diff --git a/src/netlink.c b/src/netlink.c
index 10951f96..22150f20 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -21,6 +21,8 @@
 #include <libnftnl/chain.h>
 #include <libnftnl/expr.h>
 #include <libnftnl/set.h>
+#include <libnftnl/common.h>
+#include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nf_tables.h>
 #include <linux/netfilter.h>
 
@@ -33,6 +35,7 @@
 #include <erec.h>
 
 static struct mnl_socket *nf_sock;
+static struct mnl_socket *nf_mon_sock;
 
 const struct input_descriptor indesc_netlink = {
 	.name	= "netlink",
@@ -43,12 +46,18 @@ const struct location netlink_location = {
 	.indesc	= &indesc_netlink,
 };
 
-static void __init netlink_open_sock(void)
+static struct mnl_socket *nfsock_open(void)
 {
-	nf_sock = mnl_socket_open(NETLINK_NETFILTER);
-	if (nf_sock == NULL)
+	struct mnl_socket *s = mnl_socket_open(NETLINK_NETFILTER);
+	if (s == NULL)
 		netlink_open_error();
 
+	return s;
+}
+
+static void __init netlink_open_sock(void)
+{
+	nf_sock = nfsock_open();
 	fcntl(mnl_socket_get_fd(nf_sock), F_SETFL, O_NONBLOCK);
 	mnl_batch_init();
 }
@@ -56,6 +65,20 @@ static void __init netlink_open_sock(void)
 static void __exit netlink_close_sock(void)
 {
 	mnl_socket_close(nf_sock);
+	if (nf_mon_sock)
+		mnl_socket_close(nf_mon_sock);
+}
+
+static void netlink_open_mon_sock(void)
+{
+	nf_mon_sock = nfsock_open();
+}
+
+void __noreturn netlink_abi_error(void)
+{
+	fprintf(stderr, "E: Contact urgently your Linux kernel vendor. "
+		"Netlink ABI is broken: %s\n", strerror(errno));
+	exit(NFT_EXIT_FAILURE);
 }
 
 int netlink_io_error(struct netlink_ctx *ctx, const struct location *loc,
@@ -1062,3 +1085,521 @@ struct nft_ruleset *netlink_dump_ruleset(struct netlink_ctx *ctx,
 
 	return rs;
 }
+
+static struct nft_table *netlink_table_alloc(const struct nlmsghdr *nlh)
+{
+	struct nft_table *nlt = nft_table_alloc();
+	if (nlt == NULL)
+		memory_allocation_error();
+
+	if (nft_table_nlmsg_parse(nlh, nlt) < 0)
+		netlink_abi_error();
+
+	return nlt;
+}
+
+static struct nft_chain *netlink_chain_alloc(const struct nlmsghdr *nlh)
+{
+	struct nft_chain *nlc = nft_chain_alloc();
+	if (nlc == NULL)
+		memory_allocation_error();
+
+	if (nft_chain_nlmsg_parse(nlh, nlc) < 0)
+		netlink_abi_error();
+
+	return nlc;
+}
+
+static struct nft_set *netlink_set_alloc(const struct nlmsghdr *nlh)
+{
+	struct nft_set *nls = nft_set_alloc();
+	if (nls == NULL)
+		memory_allocation_error();
+
+	if (nft_set_nlmsg_parse(nlh, nls) < 0)
+		netlink_abi_error();
+
+	return nls;
+}
+
+static struct nft_set *netlink_setelem_alloc(const struct nlmsghdr *nlh)
+{
+	struct nft_set *nls = nft_set_alloc();
+	if (nls == NULL)
+		memory_allocation_error();
+
+	if (nft_set_elems_nlmsg_parse(nlh, nls) < 0)
+		netlink_abi_error();
+
+	return nls;
+}
+
+static struct nft_rule *netlink_rule_alloc(const struct nlmsghdr *nlh)
+{
+	struct nft_rule *nlr = nft_rule_alloc();
+	if (nlr == NULL)
+		memory_allocation_error();
+
+	if (nft_rule_nlmsg_parse(nlh, nlr) < 0)
+		netlink_abi_error();
+
+	return nlr;
+}
+
+static uint32_t netlink_msg2nftnl_of(uint32_t msg)
+{
+	switch (msg) {
+	case NFT_MSG_NEWTABLE:
+	case NFT_MSG_NEWCHAIN:
+	case NFT_MSG_NEWSET:
+	case NFT_MSG_NEWSETELEM:
+	case NFT_MSG_NEWRULE:
+		return NFT_OF_EVENT_NEW;
+	case NFT_MSG_DELTABLE:
+	case NFT_MSG_DELCHAIN:
+	case NFT_MSG_DELSET:
+	case NFT_MSG_DELSETELEM:
+	case NFT_MSG_DELRULE:
+		return NFT_OF_EVENT_DEL;
+	}
+
+	return 0;
+}
+
+static int netlink_events_table_cb(const struct nlmsghdr *nlh, int type,
+				   struct netlink_mon_handler *monh)
+{
+	uint32_t family;
+	struct nft_table *nlt = netlink_table_alloc(nlh);
+
+	if (monh->format == NFT_OUTPUT_DEFAULT) {
+		if (type == NFT_MSG_NEWTABLE) {
+			if (nlh->nlmsg_flags & NLM_F_EXCL)
+				printf("update table ");
+			else
+				printf("add table ");
+		} else {
+			printf("delete table ");
+		}
+
+		family = nft_table_attr_get_u32(nlt, NFT_TABLE_ATTR_FAMILY);
+
+		printf("%s %s\n", family2str(family),
+		       nft_table_attr_get_str(nlt, NFT_TABLE_ATTR_NAME));
+	} else {
+		nft_table_fprintf(stdout, nlt, monh->format,
+				  netlink_msg2nftnl_of(type));
+		fprintf(stdout, "\n");
+	}
+
+	nft_table_free(nlt);
+	return MNL_CB_OK;
+}
+
+static int netlink_events_chain_cb(const struct nlmsghdr *nlh, int type,
+				   struct netlink_mon_handler *monh)
+{
+	struct chain *c;
+	uint32_t family;
+	struct nft_chain *nlc = netlink_chain_alloc(nlh);
+
+	if (monh->format == NFT_OUTPUT_DEFAULT) {
+		if (type == NFT_MSG_NEWCHAIN) {
+			if (nlh->nlmsg_flags & NLM_F_EXCL)
+				printf("update ");
+			else
+				printf("add ");
+
+			c = netlink_delinearize_chain(monh->ctx, nlc);
+			chain_print_plain(c);
+			chain_free(c);
+		} else {
+			family = nft_chain_attr_get_u32(nlc,
+							NFT_CHAIN_ATTR_FAMILY);
+			printf("delete chain %s %s %s\n", family2str(family),
+			       nft_chain_attr_get_str(nlc,
+						      NFT_CHAIN_ATTR_TABLE),
+			       nft_chain_attr_get_str(nlc,
+						      NFT_CHAIN_ATTR_NAME));
+		}
+	} else {
+		nft_chain_fprintf(stdout, nlc, monh->format,
+				  netlink_msg2nftnl_of(type));
+		fprintf(stdout, "\n");
+	}
+
+	nft_chain_free(nlc);
+	return MNL_CB_OK;
+}
+
+static int netlink_events_set_cb(const struct nlmsghdr *nlh, int type,
+				 struct netlink_mon_handler *monh)
+{
+	struct set *set;
+	uint32_t family, flags;
+	struct nft_set *nls = netlink_set_alloc(nlh);
+
+	flags = nft_set_attr_get_u32(nls, NFT_SET_ATTR_FLAGS);
+	if (flags & SET_F_ANONYMOUS)
+		goto out;
+
+	if (monh->format == NFT_OUTPUT_DEFAULT) {
+		if (type == NFT_MSG_NEWSET) {
+			printf("add ");
+			set = netlink_delinearize_set(monh->ctx, nls);
+			set_print_plain(set);
+			set_free(set);
+		} else {
+			family = nft_set_attr_get_u32(nls,
+						      NFT_SET_ATTR_FAMILY);
+			printf("delete set %s %s %s",
+			       family2str(family),
+			       nft_set_attr_get_str(nls, NFT_SET_ATTR_TABLE),
+			       nft_set_attr_get_str(nls, NFT_SET_ATTR_NAME));
+		}
+
+		printf("\n");
+
+	} else {
+		nft_set_fprintf(stdout, nls, monh->format,
+				netlink_msg2nftnl_of(type));
+		fprintf(stdout, "\n");
+	}
+
+out:
+	nft_set_free(nls);
+	return MNL_CB_OK;
+}
+
+static int netlink_events_setelem_cb(const struct nlmsghdr *nlh, int type,
+				     struct netlink_mon_handler *monh)
+{
+	struct nft_set_elem *nlse;
+	struct nft_set_elems_iter *nlsei;
+	struct set *dummyset;
+	struct set *set;
+	const char *setname, *table;
+	uint32_t family;
+	struct nft_set *nls = netlink_setelem_alloc(nlh);
+
+	table = nft_set_attr_get_str(nls, NFT_SET_ATTR_TABLE);
+	setname = nft_set_attr_get_str(nls, NFT_SET_ATTR_NAME);
+	family = nft_set_attr_get_u32(nls, NFT_SET_ATTR_FAMILY);
+
+	set = set_lookup_global(family, table, setname);
+	if (set == NULL) {
+		fprintf(stderr, "W: Received event for an unknown set.");
+		goto out;
+	}
+
+	if (monh->format == NFT_OUTPUT_DEFAULT) {
+		if (set->flags & SET_F_ANONYMOUS)
+			goto out;
+
+		/* we want to 'delinearize' the set_elem, but don't
+		 * modify the original cached set. This path is only
+		 * used by named sets, so use a dummy set.
+		 */
+		dummyset = set_alloc(monh->loc);
+		dummyset->keytype = set->keytype;
+		dummyset->datatype = set->datatype;
+		dummyset->init = set_expr_alloc(monh->loc);
+
+		nlsei = nft_set_elems_iter_create(nls);
+		if (nlsei == NULL)
+			memory_allocation_error();
+
+		nlse = nft_set_elems_iter_next(nlsei);
+		while (nlse != NULL) {
+			if (netlink_delinearize_setelem(nlse, dummyset) < 0) {
+				set_free(dummyset);
+				nft_set_elems_iter_destroy(nlsei);
+				goto out;
+			}
+			nlse = nft_set_elems_iter_next(nlsei);
+		}
+		nft_set_elems_iter_destroy(nlsei);
+
+		if (type == NFT_MSG_NEWSETELEM)
+			printf("add ");
+		else
+			printf("delete ");
+
+		printf("element %s %s %s ", family2str(family), table, setname);
+		expr_print(dummyset->init);
+		printf("\n");
+
+		set_free(dummyset);
+	} else {
+		nft_set_fprintf(stdout, nls, monh->format,
+				netlink_msg2nftnl_of(type));
+		fprintf(stdout, "\n");
+	}
+
+out:
+	nft_set_free(nls);
+	return MNL_CB_OK;
+}
+
+static int netlink_events_rule_cb(const struct nlmsghdr *nlh, int type,
+				  struct netlink_mon_handler *monh)
+{
+	struct rule *r;
+	uint32_t fam;
+	const char *family;
+	const char *table;
+	const char *chain;
+	uint64_t handle;
+	struct nft_rule *nlr = netlink_rule_alloc(nlh);
+
+	if (monh->format == NFT_OUTPUT_DEFAULT) {
+		fam = nft_rule_attr_get_u32(nlr, NFT_RULE_ATTR_FAMILY);
+		family = family2str(fam);
+		table = nft_rule_attr_get_str(nlr, NFT_RULE_ATTR_TABLE);
+		chain = nft_rule_attr_get_str(nlr, NFT_RULE_ATTR_CHAIN);
+		handle = nft_rule_attr_get_u64(nlr, NFT_RULE_ATTR_HANDLE);
+
+		if (type == NFT_MSG_NEWRULE) {
+			r = netlink_delinearize_rule(monh->ctx, nlr);
+
+			printf("add rule %s %s %s", family, table, chain);
+			rule_print(r);
+			printf("\n");
+
+			rule_free(r);
+			goto out;
+		}
+
+		printf("delete rule %s %s %s handle %u\n",
+		       family, table, chain, (unsigned int)handle);
+	} else {
+		nft_rule_fprintf(stdout, nlr, monh->format,
+				 netlink_msg2nftnl_of(type));
+		fprintf(stdout, "\n");
+	}
+
+out:
+	nft_rule_free(nlr);
+	return MNL_CB_OK;
+}
+
+static void netlink_events_cache_addtable(struct netlink_mon_handler *monh,
+					  const struct nlmsghdr *nlh)
+{
+	struct table *t;
+	struct nft_table *nlt = netlink_table_alloc(nlh);
+
+	t = netlink_delinearize_table(monh->ctx, nlt);
+	table_add_hash(t);
+
+	nft_table_free(nlt);
+}
+
+static void netlink_events_cache_deltable(struct netlink_mon_handler *monh,
+					  const struct nlmsghdr *nlh)
+{
+	struct table *t;
+	struct handle h;
+	struct nft_table *nlt = netlink_table_alloc(nlh);
+
+	h.family = nft_table_attr_get_u32(nlt, NFT_TABLE_ATTR_FAMILY);
+	h.table = nft_table_attr_get_str(nlt, NFT_TABLE_ATTR_NAME);
+
+	t = table_lookup(&h);
+	if (t == NULL)
+		goto out;
+
+	list_del(&t->list);
+	table_free(t);
+
+out:
+	nft_table_free(nlt);
+}
+
+static void netlink_events_cache_addset(struct netlink_mon_handler *monh,
+					const struct nlmsghdr *nlh)
+{
+	struct set *s;
+	LIST_HEAD(msgs);
+	struct table *t;
+	struct netlink_ctx set_tmpctx;
+	struct nft_set *nls = netlink_set_alloc(nlh);
+
+	memset(&set_tmpctx, 0, sizeof(set_tmpctx));
+	init_list_head(&set_tmpctx.list);
+	init_list_head(&msgs);
+	set_tmpctx.msgs = &msgs;
+
+	s = netlink_delinearize_set(&set_tmpctx, nls);
+	s->init = set_expr_alloc(monh->loc);
+
+	t = table_lookup(&s->handle);
+	if (t == NULL) {
+		fprintf(stderr, "W: Unable to cache set: table not found.\n");
+		goto out;
+	}
+
+	set_add_hash(s, t);
+out:
+	nft_set_free(nls);
+}
+
+static void netlink_events_cache_addsetelem(struct netlink_mon_handler *monh,
+					    const struct nlmsghdr *nlh)
+{
+	struct set *set;
+	struct nft_set_elem *nlse;
+	struct nft_set_elems_iter *nlsei;
+	const char *table, *setname;
+	struct nft_set *nls = netlink_setelem_alloc(nlh);
+
+	table = nft_set_attr_get_str(nls, NFT_SET_ATTR_TABLE);
+	setname = nft_set_attr_get_str(nls, NFT_SET_ATTR_NAME);
+
+	set = set_lookup_global(nft_set_attr_get_u32(nls, NFT_SET_ATTR_FAMILY),
+				table, setname);
+	if (set == NULL) {
+		fprintf(stderr,
+			"W: Unable to cache set_elem. Set not found.\n");
+		goto out;
+	}
+
+	nlsei = nft_set_elems_iter_create(nls);
+	if (nlsei == NULL)
+		memory_allocation_error();
+
+	nlse = nft_set_elems_iter_next(nlsei);
+	while (nlse != NULL) {
+		if (netlink_delinearize_setelem(nlse, set) < 0) {
+			fprintf(stderr,
+				"W: Unable to cache set_elem. "
+				"Delinearize failed.\n");
+			nft_set_elems_iter_destroy(nlsei);
+			goto out;
+		}
+		nlse = nft_set_elems_iter_next(nlsei);
+	}
+	nft_set_elems_iter_destroy(nlsei);
+
+out:
+	nft_set_free(nls);
+}
+
+static void netlink_events_cache_delsets(struct netlink_mon_handler *monh,
+					 const struct nlmsghdr *nlh)
+{
+	struct set *s;
+	uint32_t family;
+	struct nft_rule_expr *nlre;
+	struct nft_rule_expr_iter *nlrei;
+	const char *expr_name, *set_name, *table;
+	struct nft_rule *nlr = netlink_rule_alloc(nlh);
+
+	nlrei = nft_rule_expr_iter_create(nlr);
+	if (nlrei == NULL)
+		memory_allocation_error();
+
+	family = nft_rule_attr_get_u32(nlr, NFT_RULE_ATTR_FAMILY);
+	table = nft_rule_attr_get_str(nlr, NFT_RULE_ATTR_TABLE);
+
+	nlre = nft_rule_expr_iter_next(nlrei);
+	while (nlre != NULL) {
+		expr_name = nft_rule_expr_get_str(nlre,
+						  NFT_RULE_EXPR_ATTR_NAME);
+		if (strcmp(expr_name, "lookup") != 0)
+			goto next;
+
+		set_name = nft_rule_expr_get_str(nlre, NFT_EXPR_LOOKUP_SET);
+		s = set_lookup_global(family, table, set_name);
+		if (s == NULL)
+			goto next;
+
+		list_del(&s->list);
+		set_free(s);
+next:
+		nlre = nft_rule_expr_iter_next(nlrei);
+	}
+	nft_rule_expr_iter_destroy(nlrei);
+
+	nft_rule_free(nlr);
+}
+
+static void netlink_events_cache_update(struct netlink_mon_handler *monh,
+					const struct nlmsghdr *nlh, int type)
+{
+	if (!monh->cache_needed)
+		return;
+
+	switch (type) {
+	case NFT_MSG_NEWTABLE:
+		netlink_events_cache_addtable(monh, nlh);
+		break;
+	case NFT_MSG_DELTABLE:
+		netlink_events_cache_deltable(monh, nlh);
+		break;
+	case NFT_MSG_NEWSET:
+		netlink_events_cache_addset(monh, nlh);
+		break;
+	case NFT_MSG_NEWSETELEM:
+		netlink_events_cache_addsetelem(monh, nlh);
+		break;
+	case NFT_MSG_DELRULE:
+		/* there are no notification for anon-set deletion */
+		netlink_events_cache_delsets(monh, nlh);
+		break;
+	}
+}
+
+static int netlink_events_cb(const struct nlmsghdr *nlh, void *data)
+{
+	int ret = MNL_CB_OK;
+	int type = nlh->nlmsg_type & 0xFF;
+	struct netlink_mon_handler *monh = (struct netlink_mon_handler *)data;
+
+	netlink_events_cache_update(monh, nlh, type);
+
+	if (!(monh->monitor_flags & (1 << type)))
+		return ret;
+
+	switch (type) {
+	case NFT_MSG_NEWTABLE:
+	case NFT_MSG_DELTABLE:
+		ret = netlink_events_table_cb(nlh, type, monh);
+		break;
+	case NFT_MSG_NEWCHAIN:
+	case NFT_MSG_DELCHAIN:
+		ret = netlink_events_chain_cb(nlh, type, monh);
+		break;
+	case NFT_MSG_NEWSET:
+	case NFT_MSG_DELSET:		/* nft {add|delete} set */
+		ret = netlink_events_set_cb(nlh, type, monh);
+		break;
+	case NFT_MSG_NEWSETELEM:
+	case NFT_MSG_DELSETELEM:	/* nft {add|delete} element */
+		ret = netlink_events_setelem_cb(nlh, type, monh);
+		break;
+	case NFT_MSG_NEWRULE:
+	case NFT_MSG_DELRULE:
+		ret = netlink_events_rule_cb(nlh, type, monh);
+		break;
+	default:
+		BUG("Unknow event received from netlink.\n");
+		break;
+	}
+
+	return ret;
+}
+
+int netlink_monitor(struct netlink_mon_handler *monhandler)
+{
+	netlink_open_mon_sock();
+
+	if (mnl_socket_bind(nf_mon_sock, (1 << (NFNLGRP_NFTABLES-1)),
+			    MNL_SOCKET_AUTOPID) < 0)
+		return netlink_io_error(monhandler->ctx, monhandler->loc,
+					"Could not bind to netlink socket %s",
+					strerror(errno));
+
+	return mnl_nft_event_listener(nf_mon_sock, netlink_events_cb,
+				      monhandler);
+}