selftests: netfilter: add nfqueue test case

Add a test case to check nf queue infrastructure.
Could be extended in the future to also cover serialization of
conntrack, uid and secctx attributes in nfqueue.

For now, this checks that 'queue bypass' works, that a queue rule with
no bypass option blocks traffic and that userspace receives the expected
number of packets.
For this we add two queues and hook all of
prerouting/input/forward/output/postrouting.

Packets get queued twice with a dummy base chain in between:
This passes with current nf tree, but reverting
commit 946c0d8 ("netfilter: nf_queue: fix reinject verdict handling")
makes this trip (it processes 30 instead of expected 20 packets).

v2: update config file with queue and other options missing/needed for
other tests.
v3: also test with tcp, this reveals problem with commit
28f8bfd ("netfilter: Support iif matches in POSTROUTING"), due to
skb->dev pointing at another skb in the retransmit rbtree (skb->dev
aliases to rbnode child).

Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>

Author: Florian Westphal

tools/testing/selftests/netfilter/Makefile

@@ -3,6 +3,10 @@
 
 TEST_PROGS := nft_trans_stress.sh nft_nat.sh bridge_brouter.sh \
 	conntrack_icmp_related.sh nft_flowtable.sh ipvs.sh \
-	nft_concat_range.sh
+	nft_concat_range.sh \
+	nft_queue.sh
+
+LDLIBS = -lmnl
+TEST_GEN_FILES =  nf-queue
 
 include ../lib.mk

tools/testing/selftests/netfilter/config

@@ -1,2 +1,8 @@
 CONFIG_NET_NS=y
 CONFIG_NF_TABLES_INET=y
+CONFIG_NFT_QUEUE=m
+CONFIG_NFT_NAT=m
+CONFIG_NFT_REDIR=m
+CONFIG_NFT_MASQ=m
+CONFIG_NFT_FLOW_OFFLOAD=m
+CONFIG_NF_CT_NETLINK=m

tools/testing/selftests/netfilter/nf-queue.c

@@ -0,0 +1,352 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include <arpa/inet.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_queue.h>
+
+struct options {
+	bool count_packets;
+	int verbose;
+	unsigned int queue_num;
+	unsigned int timeout;
+};
+
+static unsigned int queue_stats[5];
+static struct options opts;
+
+static void help(const char *p)
+{
+	printf("Usage: %s [-c|-v [-vv] ] [-t timeout] [-q queue_num]\n", p);
+}
+
+static int parse_attr_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	/* skip unsupported attribute in user-space */
+	if (mnl_attr_type_valid(attr, NFQA_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch (type) {
+	case NFQA_MARK:
+	case NFQA_IFINDEX_INDEV:
+	case NFQA_IFINDEX_OUTDEV:
+	case NFQA_IFINDEX_PHYSINDEV:
+	case NFQA_IFINDEX_PHYSOUTDEV:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFQA_TIMESTAMP:
+		if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
+		    sizeof(struct nfqnl_msg_packet_timestamp)) < 0) {
+			perror("mnl_attr_validate2");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFQA_HWADDR:
+		if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
+		    sizeof(struct nfqnl_msg_packet_hw)) < 0) {
+			perror("mnl_attr_validate2");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFQA_PAYLOAD:
+		break;
+	}
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static int queue_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nlattr *tb[NFQA_MAX+1] = { 0 };
+	struct nfqnl_msg_packet_hdr *ph = NULL;
+	uint32_t id = 0;
+
+	(void)data;
+
+	mnl_attr_parse(nlh, sizeof(struct nfgenmsg), parse_attr_cb, tb);
+	if (tb[NFQA_PACKET_HDR]) {
+		ph = mnl_attr_get_payload(tb[NFQA_PACKET_HDR]);
+		id = ntohl(ph->packet_id);
+
+		if (opts.verbose > 0)
+			printf("packet hook=%u, hwproto 0x%x",
+				ntohs(ph->hw_protocol), ph->hook);
+
+		if (ph->hook >= 5) {
+			fprintf(stderr, "Unknown hook %d\n", ph->hook);
+			return MNL_CB_ERROR;
+		}
+
+		if (opts.verbose > 0) {
+			uint32_t skbinfo = 0;
+
+			if (tb[NFQA_SKB_INFO])
+				skbinfo = ntohl(mnl_attr_get_u32(tb[NFQA_SKB_INFO]));
+			if (skbinfo & NFQA_SKB_CSUMNOTREADY)
+				printf(" csumnotready");
+			if (skbinfo & NFQA_SKB_GSO)
+				printf(" gso");
+			if (skbinfo & NFQA_SKB_CSUM_NOTVERIFIED)
+				printf(" csumnotverified");
+			puts("");
+		}
+
+		if (opts.count_packets)
+			queue_stats[ph->hook]++;
+	}
+
+	return MNL_CB_OK + id;
+}
+
+static struct nlmsghdr *
+nfq_build_cfg_request(char *buf, uint8_t command, int queue_num)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	struct nfqnl_msg_config_cmd cmd = {
+		.command = command,
+		.pf = htons(AF_INET),
+	};
+	struct nfgenmsg *nfg;
+
+	nlh->nlmsg_type	= (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(queue_num);
+
+	mnl_attr_put(nlh, NFQA_CFG_CMD, sizeof(cmd), &cmd);
+
+	return nlh;
+}
+
+static struct nlmsghdr *
+nfq_build_cfg_params(char *buf, uint8_t mode, int range, int queue_num)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	struct nfqnl_msg_config_params params = {
+		.copy_range = htonl(range),
+		.copy_mode = mode,
+	};
+	struct nfgenmsg *nfg;
+
+	nlh->nlmsg_type	= (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(queue_num);
+
+	mnl_attr_put(nlh, NFQA_CFG_PARAMS, sizeof(params), &params);
+
+	return nlh;
+}
+
+static struct nlmsghdr *
+nfq_build_verdict(char *buf, int id, int queue_num, int verd)
+{
+	struct nfqnl_msg_verdict_hdr vh = {
+		.verdict = htonl(verd),
+		.id = htonl(id),
+	};
+	struct nlmsghdr *nlh;
+	struct nfgenmsg *nfg;
+
+	nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+	nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(queue_num);
+
+	mnl_attr_put(nlh, NFQA_VERDICT_HDR, sizeof(vh), &vh);
+
+	return nlh;
+}
+
+static void print_stats(void)
+{
+	unsigned int last, total;
+	int i;
+
+	if (!opts.count_packets)
+		return;
+
+	total = 0;
+	last = queue_stats[0];
+
+	for (i = 0; i < 5; i++) {
+		printf("hook %d packets %08u\n", i, queue_stats[i]);
+		last = queue_stats[i];
+		total += last;
+	}
+
+	printf("%u packets total\n", total);
+}
+
+struct mnl_socket *open_queue(void)
+{
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	unsigned int queue_num;
+	struct mnl_socket *nl;
+	struct nlmsghdr *nlh;
+	struct timeval tv;
+	uint32_t flags;
+
+	nl = mnl_socket_open(NETLINK_NETFILTER);
+	if (nl == NULL) {
+		perror("mnl_socket_open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+		perror("mnl_socket_bind");
+		exit(EXIT_FAILURE);
+	}
+
+	queue_num = opts.queue_num;
+	nlh = nfq_build_cfg_request(buf, NFQNL_CFG_CMD_BIND, queue_num);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_sendto");
+		exit(EXIT_FAILURE);
+	}
+
+	nlh = nfq_build_cfg_params(buf, NFQNL_COPY_PACKET, 0xFFFF, queue_num);
+
+	flags = NFQA_CFG_F_GSO | NFQA_CFG_F_UID_GID;
+	mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(flags));
+	mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(flags));
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_sendto");
+		exit(EXIT_FAILURE);
+	}
+
+	memset(&tv, 0, sizeof(tv));
+	tv.tv_sec = opts.timeout;
+	if (opts.timeout && setsockopt(mnl_socket_get_fd(nl),
+				       SOL_SOCKET, SO_RCVTIMEO,
+				       &tv, sizeof(tv))) {
+		perror("setsockopt(SO_RCVTIMEO)");
+		exit(EXIT_FAILURE);
+	}
+
+	return nl;
+}
+
+static int mainloop(void)
+{
+	unsigned int buflen = 64 * 1024 + MNL_SOCKET_BUFFER_SIZE;
+	struct mnl_socket *nl;
+	struct nlmsghdr *nlh;
+	unsigned int portid;
+	char *buf;
+	int ret;
+
+	buf = malloc(buflen);
+	if (!buf) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+
+	nl = open_queue();
+	portid = mnl_socket_get_portid(nl);
+
+	for (;;) {
+		uint32_t id;
+
+		ret = mnl_socket_recvfrom(nl, buf, buflen);
+		if (ret == -1) {
+			if (errno == ENOBUFS)
+				continue;
+
+			if (errno == EAGAIN) {
+				errno = 0;
+				ret = 0;
+				break;
+			}
+
+			perror("mnl_socket_recvfrom");
+			exit(EXIT_FAILURE);
+		}
+
+		ret = mnl_cb_run(buf, ret, 0, portid, queue_cb, NULL);
+		if (ret < 0) {
+			perror("mnl_cb_run");
+			exit(EXIT_FAILURE);
+		}
+
+		id = ret - MNL_CB_OK;
+		nlh = nfq_build_verdict(buf, id, opts.queue_num, NF_ACCEPT);
+		if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+			perror("mnl_socket_sendto");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	mnl_socket_close(nl);
+
+	return ret;
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "chvt:q:")) != -1) {
+		switch (c) {
+		case 'c':
+			opts.count_packets = true;
+			break;
+		case 'h':
+			help(argv[0]);
+			exit(0);
+			break;
+		case 'q':
+			opts.queue_num = atoi(optarg);
+			if (opts.queue_num > 0xffff)
+				opts.queue_num = 0;
+			break;
+		case 't':
+			opts.timeout = atoi(optarg);
+			break;
+		case 'v':
+			opts.verbose++;
+			break;
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	parse_opts(argc, argv);
+
+	ret = mainloop();
+	if (opts.count_packets)
+		print_stats();
+
+	return ret;
+}