1 files changed, 472 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/ip_defrag.c b/tools/testing/selftests/net/ip_defrag.c
new file mode 100644
index 000000000..f9ed749fd
--- /dev/null
+++ b/tools/testing/selftests/net/ip_defrag.c
@@ -0,0 +1,472 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <linux/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/udp.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+static bool		cfg_do_ipv4;
+static bool		cfg_do_ipv6;
+static bool		cfg_verbose;
+static bool		cfg_overlap;
+static bool		cfg_permissive;
+static unsigned short	cfg_port = 9000;
+
+const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) };
+const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT;
+
+#define IP4_HLEN	(sizeof(struct iphdr))
+#define IP6_HLEN	(sizeof(struct ip6_hdr))
+#define UDP_HLEN	(sizeof(struct udphdr))
+
+/* IPv6 fragment header lenth. */
+#define FRAG_HLEN	8
+
+static int payload_len;
+static int max_frag_len;
+
+#define MSG_LEN_MAX	10000	/* Max UDP payload length. */
+
+#define IP4_MF		(1u << 13)  /* IPv4 MF flag. */
+#define IP6_MF		(1)  /* IPv6 MF flag. */
+
+#define CSUM_MANGLED_0 (0xffff)
+
+static uint8_t udp_payload[MSG_LEN_MAX];
+static uint8_t ip_frame[IP_MAXPACKET];
+static uint32_t ip_id = 0xabcd;
+static int msg_counter;
+static int frag_counter;
+static unsigned int seed;
+
+/* Receive a UDP packet. Validate it matches udp_payload. */
+static void recv_validate_udp(int fd_udp)
+{
+	ssize_t ret;
+	static uint8_t recv_buff[MSG_LEN_MAX];
+
+	ret = recv(fd_udp, recv_buff, payload_len, 0);
+	msg_counter++;
+
+	if (cfg_overlap) {
+		if (ret == -1 && (errno == ETIMEDOUT || errno == EAGAIN))
+			return;  /* OK */
+		if (!cfg_permissive) {
+			if (ret != -1)
+				error(1, 0, "recv: expected timeout; got %d",
+					(int)ret);
+			error(1, errno, "recv: expected timeout: %d", errno);
+		}
+	}
+
+	if (ret == -1)
+		error(1, errno, "recv: payload_len = %d max_frag_len = %d",
+			payload_len, max_frag_len);
+	if (ret != payload_len)
+		error(1, 0, "recv: wrong size: %d vs %d", (int)ret, payload_len);
+	if (memcmp(udp_payload, recv_buff, payload_len))
+		error(1, 0, "recv: wrong data");
+}
+
+static uint32_t raw_checksum(uint8_t *buf, int len, uint32_t sum)
+{
+	int i;
+
+	for (i = 0; i < (len & ~1U); i += 2) {
+		sum += (u_int16_t)ntohs(*((u_int16_t *)(buf + i)));
+		if (sum > 0xffff)
+			sum -= 0xffff;
+	}
+
+	if (i < len) {
+		sum += buf[i] << 8;
+		if (sum > 0xffff)
+			sum -= 0xffff;
+	}
+
+	return sum;
+}
+
+static uint16_t udp_checksum(struct ip *iphdr, struct udphdr *udphdr)
+{
+	uint32_t sum = 0;
+	uint16_t res;
+
+	sum = raw_checksum((uint8_t *)&iphdr->ip_src, 2 * sizeof(iphdr->ip_src),
+				IPPROTO_UDP + (uint32_t)(UDP_HLEN + payload_len));
+	sum = raw_checksum((uint8_t *)udphdr, UDP_HLEN, sum);
+	sum = raw_checksum((uint8_t *)udp_payload, payload_len, sum);
+	res = 0xffff & ~sum;
+	if (res)
+		return htons(res);
+	else
+		return CSUM_MANGLED_0;
+}
+
+static uint16_t udp6_checksum(struct ip6_hdr *iphdr, struct udphdr *udphdr)
+{
+	uint32_t sum = 0;
+	uint16_t res;
+
+	sum = raw_checksum((uint8_t *)&iphdr->ip6_src, 2 * sizeof(iphdr->ip6_src),
+				IPPROTO_UDP);
+	sum = raw_checksum((uint8_t *)&udphdr->len, sizeof(udphdr->len), sum);
+	sum = raw_checksum((uint8_t *)udphdr, UDP_HLEN, sum);
+	sum = raw_checksum((uint8_t *)udp_payload, payload_len, sum);
+	res = 0xffff & ~sum;
+	if (res)
+		return htons(res);
+	else
+		return CSUM_MANGLED_0;
+}
+
+static void send_fragment(int fd_raw, struct sockaddr *addr, socklen_t alen,
+				int offset, bool ipv6)
+{
+	int frag_len;
+	int res;
+	int payload_offset = offset > 0 ? offset - UDP_HLEN : 0;
+	uint8_t *frag_start = ipv6 ? ip_frame + IP6_HLEN + FRAG_HLEN :
+					ip_frame + IP4_HLEN;
+
+	if (offset == 0) {
+		struct udphdr udphdr;
+		udphdr.source = htons(cfg_port + 1);
+		udphdr.dest = htons(cfg_port);
+		udphdr.len = htons(UDP_HLEN + payload_len);
+		udphdr.check = 0;
+		if (ipv6)
+			udphdr.check = udp6_checksum((struct ip6_hdr *)ip_frame, &udphdr);
+		else
+			udphdr.check = udp_checksum((struct ip *)ip_frame, &udphdr);
+		memcpy(frag_start, &udphdr, UDP_HLEN);
+	}
+
+	if (ipv6) {
+		struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
+		struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
+		if (payload_len - payload_offset <= max_frag_len && offset > 0) {
+			/* This is the last fragment. */
+			frag_len = FRAG_HLEN + payload_len - payload_offset;
+			fraghdr->ip6f_offlg = htons(offset);
+		} else {
+			frag_len = FRAG_HLEN + max_frag_len;
+			fraghdr->ip6f_offlg = htons(offset | IP6_MF);
+		}
+		ip6hdr->ip6_plen = htons(frag_len);
+		if (offset == 0)
+			memcpy(frag_start + UDP_HLEN, udp_payload,
+				frag_len - FRAG_HLEN - UDP_HLEN);
+		else
+			memcpy(frag_start, udp_payload + payload_offset,
+				frag_len - FRAG_HLEN);
+		frag_len += IP6_HLEN;
+	} else {
+		struct ip *iphdr = (struct ip *)ip_frame;
+		if (payload_len - payload_offset <= max_frag_len && offset > 0) {
+			/* This is the last fragment. */
+			frag_len = IP4_HLEN + payload_len - payload_offset;
+			iphdr->ip_off = htons(offset / 8);
+		} else {
+			frag_len = IP4_HLEN + max_frag_len;
+			iphdr->ip_off = htons(offset / 8 | IP4_MF);
+		}
+		iphdr->ip_len = htons(frag_len);
+		if (offset == 0)
+			memcpy(frag_start + UDP_HLEN, udp_payload,
+				frag_len - IP4_HLEN - UDP_HLEN);
+		else
+			memcpy(frag_start, udp_payload + payload_offset,
+				frag_len - IP4_HLEN);
+	}
+
+	res = sendto(fd_raw, ip_frame, frag_len, 0, addr, alen);
+	if (res < 0 && errno != EPERM)
+		error(1, errno, "send_fragment");
+	if (res >= 0 && res != frag_len)
+		error(1, 0, "send_fragment: %d vs %d", res, frag_len);
+
+	frag_counter++;
+}
+
+static void send_udp_frags(int fd_raw, struct sockaddr *addr,
+				socklen_t alen, bool ipv6)
+{
+	struct ip *iphdr = (struct ip *)ip_frame;
+	struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
+	int res;
+	int offset;
+	int frag_len;
+
+	/* Send the UDP datagram using raw IP fragments: the 0th fragment
+	 * has the UDP header; other fragments are pieces of udp_payload
+	 * split in chunks of frag_len size.
+	 *
+	 * Odd fragments (1st, 3rd, 5th, etc.) are sent out first, then
+	 * even fragments (0th, 2nd, etc.) are sent out.
+	 */
+	if (ipv6) {
+		struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
+		((struct sockaddr_in6 *)addr)->sin6_port = 0;
+		memset(ip6hdr, 0, sizeof(*ip6hdr));
+		ip6hdr->ip6_flow = htonl(6<<28);  /* Version. */
+		ip6hdr->ip6_nxt = IPPROTO_FRAGMENT;
+		ip6hdr->ip6_hops = 255;
+		ip6hdr->ip6_src = addr6;
+		ip6hdr->ip6_dst = addr6;
+		fraghdr->ip6f_nxt = IPPROTO_UDP;
+		fraghdr->ip6f_reserved = 0;
+		fraghdr->ip6f_ident = htonl(ip_id++);
+	} else {
+		memset(iphdr, 0, sizeof(*iphdr));
+		iphdr->ip_hl = 5;
+		iphdr->ip_v = 4;
+		iphdr->ip_tos = 0;
+		iphdr->ip_id = htons(ip_id++);
+		iphdr->ip_ttl = 0x40;
+		iphdr->ip_p = IPPROTO_UDP;
+		iphdr->ip_src.s_addr = htonl(INADDR_LOOPBACK);
+		iphdr->ip_dst = addr4;
+		iphdr->ip_sum = 0;
+	}
+
+	/* Occasionally test in-order fragments. */
+	if (!cfg_overlap && (rand() % 100 < 15)) {
+		offset = 0;
+		while (offset < (UDP_HLEN + payload_len)) {
+			send_fragment(fd_raw, addr, alen, offset, ipv6);
+			offset += max_frag_len;
+		}
+		return;
+	}
+
+	/* Occasionally test IPv4 "runs" (see net/ipv4/ip_fragment.c) */
+	if (!cfg_overlap && (rand() % 100 < 20) &&
+			(payload_len > 9 * max_frag_len)) {
+		offset = 6 * max_frag_len;
+		while (offset < (UDP_HLEN + payload_len)) {
+			send_fragment(fd_raw, addr, alen, offset, ipv6);
+			offset += max_frag_len;
+		}
+		offset = 3 * max_frag_len;
+		while (offset < 6 * max_frag_len) {
+			send_fragment(fd_raw, addr, alen, offset, ipv6);
+			offset += max_frag_len;
+		}
+		offset = 0;
+		while (offset < 3 * max_frag_len) {
+			send_fragment(fd_raw, addr, alen, offset, ipv6);
+			offset += max_frag_len;
+		}
+		return;
+	}
+
+	/* Odd fragments. */
+	offset = max_frag_len;
+	while (offset < (UDP_HLEN + payload_len)) {
+		send_fragment(fd_raw, addr, alen, offset, ipv6);
+		/* IPv4 ignores duplicates, so randomly send a duplicate. */
+		if (rand() % 100 == 1)
+			send_fragment(fd_raw, addr, alen, offset, ipv6);
+		offset += 2 * max_frag_len;
+	}
+
+	if (cfg_overlap) {
+		/* Send an extra random fragment.
+		 *
+		 * Duplicates and some fragments completely inside
+		 * previously sent fragments are dropped/ignored. So
+		 * random offset and frag_len can result in a dropped
+		 * fragment instead of a dropped queue/packet. Thus we
+		 * hard-code offset and frag_len.
+		 */
+		if (max_frag_len * 4 < payload_len || max_frag_len < 16) {
+			/* not enough payload for random offset and frag_len. */
+			offset = 8;
+			frag_len = UDP_HLEN + max_frag_len;
+		} else {
+			offset = rand() % (payload_len / 2);
+			frag_len = 2 * max_frag_len + 1 + rand() % 256;
+		}
+		if (ipv6) {
+			struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
+			/* sendto() returns EINVAL if offset + frag_len is too small. */
+			/* In IPv6 if !!(frag_len % 8), the fragment is dropped. */
+			frag_len &= ~0x7;
+			fraghdr->ip6f_offlg = htons(offset / 8 | IP6_MF);
+			ip6hdr->ip6_plen = htons(frag_len);
+			frag_len += IP6_HLEN;
+		} else {
+			frag_len += IP4_HLEN;
+			iphdr->ip_off = htons(offset / 8 | IP4_MF);
+			iphdr->ip_len = htons(frag_len);
+		}
+		res = sendto(fd_raw, ip_frame, frag_len, 0, addr, alen);
+		if (res < 0 && errno != EPERM)
+			error(1, errno, "sendto overlap: %d", frag_len);
+		if (res >= 0 && res != frag_len)
+			error(1, 0, "sendto overlap: %d vs %d", (int)res, frag_len);
+		frag_counter++;
+	}
+
+	/* Event fragments. */
+	offset = 0;
+	while (offset < (UDP_HLEN + payload_len)) {
+		send_fragment(fd_raw, addr, alen, offset, ipv6);
+		/* IPv4 ignores duplicates, so randomly send a duplicate. */
+		if (rand() % 100 == 1)
+			send_fragment(fd_raw, addr, alen, offset, ipv6);
+		offset += 2 * max_frag_len;
+	}
+}
+
+static void run_test(struct sockaddr *addr, socklen_t alen, bool ipv6)
+{
+	int fd_tx_raw, fd_rx_udp;
+	/* Frag queue timeout is set to one second in the calling script;
+	 * socket timeout should be just a bit longer to avoid tests interfering
+	 * with each other.
+	 */
+	struct timeval tv = { .tv_sec = 1, .tv_usec = 10 };
+	int idx;
+	int min_frag_len = 8;
+
+	/* Initialize the payload. */
+	for (idx = 0; idx < MSG_LEN_MAX; ++idx)
+		udp_payload[idx] = idx % 256;
+
+	/* Open sockets. */
+	fd_tx_raw = socket(addr->sa_family, SOCK_RAW, IPPROTO_RAW);
+	if (fd_tx_raw == -1)
+		error(1, errno, "socket tx_raw");
+
+	fd_rx_udp = socket(addr->sa_family, SOCK_DGRAM, 0);
+	if (fd_rx_udp == -1)
+		error(1, errno, "socket rx_udp");
+	if (bind(fd_rx_udp, addr, alen))
+		error(1, errno, "bind");
+	/* Fail fast. */
+	if (setsockopt(fd_rx_udp, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
+		error(1, errno, "setsockopt rcv timeout");
+
+	for (payload_len = min_frag_len; payload_len < MSG_LEN_MAX;
+			payload_len += (rand() % 4096)) {
+		if (cfg_verbose)
+			printf("payload_len: %d\n", payload_len);
+
+		if (cfg_overlap) {
+			/* With overlaps, one send/receive pair below takes
+			 * at least one second (== timeout) to run, so there
+			 * is not enough test time to run a nested loop:
+			 * the full overlap test takes 20-30 seconds.
+			 */
+			max_frag_len = min_frag_len +
+				rand() % (1500 - FRAG_HLEN - min_frag_len);
+			send_udp_frags(fd_tx_raw, addr, alen, ipv6);
+			recv_validate_udp(fd_rx_udp);
+		} else {
+			/* Without overlaps, each packet reassembly (== one
+			 * send/receive pair below) takes very little time to
+			 * run, so we can easily afford more thourough testing
+			 * with a nested loop: the full non-overlap test takes
+			 * less than one second).
+			 */
+			max_frag_len = min_frag_len;
+			do {
+				send_udp_frags(fd_tx_raw, addr, alen, ipv6);
+				recv_validate_udp(fd_rx_udp);
+				max_frag_len += 8 * (rand() % 8);
+			} while (max_frag_len < (1500 - FRAG_HLEN) &&
+				 max_frag_len <= payload_len);
+		}
+	}
+
+	/* Cleanup. */
+	if (close(fd_tx_raw))
+		error(1, errno, "close tx_raw");
+	if (close(fd_rx_udp))
+		error(1, errno, "close rx_udp");
+
+	if (cfg_verbose)
+		printf("processed %d messages, %d fragments\n",
+			msg_counter, frag_counter);
+
+	fprintf(stderr, "PASS\n");
+}
+
+
+static void run_test_v4(void)
+{
+	struct sockaddr_in addr = {0};
+
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(cfg_port);
+	addr.sin_addr = addr4;
+
+	run_test((void *)&addr, sizeof(addr), false /* !ipv6 */);
+}
+
+static void run_test_v6(void)
+{
+	struct sockaddr_in6 addr = {0};
+
+	addr.sin6_family = AF_INET6;
+	addr.sin6_port = htons(cfg_port);
+	addr.sin6_addr = addr6;
+
+	run_test((void *)&addr, sizeof(addr), true /* ipv6 */);
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "46opv")) != -1) {
+		switch (c) {
+		case '4':
+			cfg_do_ipv4 = true;
+			break;
+		case '6':
+			cfg_do_ipv6 = true;
+			break;
+		case 'o':
+			cfg_overlap = true;
+			break;
+		case 'p':
+			cfg_permissive = true;
+			break;
+		case 'v':
+			cfg_verbose = true;
+			break;
+		default:
+			error(1, 0, "%s: parse error", argv[0]);
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	parse_opts(argc, argv);
+	seed = time(NULL);
+	srand(seed);
+	/* Print the seed to track/reproduce potential failures. */
+	printf("seed = %d\n", seed);
+
+	if (cfg_do_ipv4)
+		run_test_v4();
+	if (cfg_do_ipv6)
+		run_test_v6();
+
+	return 0;
+}