Merge branch 'GRO-Toeplitz-selftests'

Coco Li says:

====================
GRO and Toeplitz hash selftests

This patch contains two selftests in net, as well as respective
scripts to run the tests on a single machine in loopback mode.
GRO: tests the Linux kernel GRO behavior
Toeplitz: tests the toeplitz hash implementation
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/Makefile

@@ -38,8 +38,10 @@ TEST_GEN_FILES += reuseaddr_ports_exhausted
 TEST_GEN_FILES += hwtstamp_config rxtimestamp timestamping txtimestamp
 TEST_GEN_FILES += ipsec
 TEST_GEN_FILES += ioam6_parser
+TEST_GEN_FILES += gro
 TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa
 TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls
+TEST_GEN_FILES += toeplitz
 
 TEST_FILES := settings
 

tools/testing/selftests/net/gro.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This testsuite provides conformance testing for GRO coalescing.
+ *
+ * Test cases:
+ * 1.data
+ *  Data packets of the same size and same header setup with correct
+ *  sequence numbers coalesce. The one exception being the last data
+ *  packet coalesced: it can be smaller than the rest and coalesced
+ *  as long as it is in the same flow.
+ * 2.ack
+ *  Pure ACK does not coalesce.
+ * 3.flags
+ *  Specific test cases: no packets with PSH, SYN, URG, RST set will
+ *  be coalesced.
+ * 4.tcp
+ *  Packets with incorrect checksum, non-consecutive seqno and
+ *  different TCP header options shouldn't coalesce. Nit: given that
+ *  some extension headers have paddings, such as timestamp, headers
+ *  that are padding differently would not be coalesced.
+ * 5.ip:
+ *  Packets with different (ECN, TTL, TOS) header, ip options or
+ *  ip fragments (ipv6) shouldn't coalesce.
+ * 6.large:
+ *  Packets larger than GRO_MAX_SIZE packets shouldn't coalesce.
+ *
+ * MSS is defined as 4096 - header because if it is too small
+ * (i.e. 1500 MTU - header), it will result in many packets,
+ * increasing the "large" test case's flakiness. This is because
+ * due to time sensitivity in the coalescing window, the receiver
+ * may not coalesce all of the packets.
+ *
+ * Note the timing issue applies to all of the test cases, so some
+ * flakiness is to be expected.
+ *
+ */
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <getopt.h>
+#include <linux/filter.h>
+#include <linux/if_packet.h>
+#include <linux/ipv6.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/tcp.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#define DPORT 8000
+#define SPORT 1500
+#define PAYLOAD_LEN 100
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+#define NUM_PACKETS 4
+#define START_SEQ 100
+#define START_ACK 100
+#define SIP6 "fdaa::2"
+#define DIP6 "fdaa::1"
+#define SIP4 "192.168.1.200"
+#define DIP4 "192.168.1.100"
+#define ETH_P_NONE 0
+#define TOTAL_HDR_LEN (ETH_HLEN + sizeof(struct ipv6hdr) + sizeof(struct tcphdr))
+#define MSS (4096 - sizeof(struct tcphdr) - sizeof(struct ipv6hdr))
+#define MAX_PAYLOAD (IP_MAXPACKET - sizeof(struct tcphdr) - sizeof(struct ipv6hdr))
+#define NUM_LARGE_PKT (MAX_PAYLOAD / MSS)
+#define MAX_HDR_LEN (ETH_HLEN + sizeof(struct ipv6hdr) + sizeof(struct tcphdr))
+
+static int proto = -1;
+static uint8_t src_mac[ETH_ALEN], dst_mac[ETH_ALEN];
+static char *testname = "data";
+static char *ifname = "eth0";
+static char *smac = "aa:00:00:00:00:02";
+static char *dmac = "aa:00:00:00:00:01";
+static bool verbose;
+static bool tx_socket = true;
+static int tcp_offset = -1;
+static int total_hdr_len = -1;
+static int ethhdr_proto = -1;
+
+static void vlog(const char *fmt, ...)
+{
+	va_list args;
+
+	if (verbose) {
+		va_start(args, fmt);
+		vfprintf(stderr, fmt, args);
+		va_end(args);
+	}
+}
+
+static void setup_sock_filter(int fd)
+{
+	const int dport_off = tcp_offset + offsetof(struct tcphdr, dest);
+	const int ethproto_off = offsetof(struct ethhdr, h_proto);
+	int optlen = 0;
+	int ipproto_off;
+	int next_off;
+
+	if (proto == PF_INET)
+		next_off = offsetof(struct iphdr, protocol);
+	else
+		next_off = offsetof(struct ipv6hdr, nexthdr);
+	ipproto_off = ETH_HLEN + next_off;
+
+	if (strcmp(testname, "ip") == 0) {
+		if (proto == PF_INET)
+			optlen = sizeof(struct ip_timestamp);
+		else
+			optlen = sizeof(struct ip6_frag);
+	}
+
+	struct sock_filter filter[] = {
+			BPF_STMT(BPF_LD  + BPF_H   + BPF_ABS, ethproto_off),
+			BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ntohs(ethhdr_proto), 0, 7),
+			BPF_STMT(BPF_LD  + BPF_B   + BPF_ABS, ipproto_off),
+			BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_TCP, 0, 5),
+			BPF_STMT(BPF_LD  + BPF_H   + BPF_ABS, dport_off),
+			BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DPORT, 2, 0),
+			BPF_STMT(BPF_LD  + BPF_H   + BPF_ABS, dport_off + optlen),
+			BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DPORT, 0, 1),
+			BPF_STMT(BPF_RET + BPF_K, 0xFFFFFFFF),
+			BPF_STMT(BPF_RET + BPF_K, 0),
+	};
+
+	struct sock_fprog bpf = {
+		.len = ARRAY_SIZE(filter),
+		.filter = filter,
+	};
+
+	if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf)) < 0)
+		error(1, errno, "error setting filter");
+}
+
+static uint32_t checksum_nofold(void *data, size_t len, uint32_t sum)
+{
+	uint16_t *words = data;
+	int i;
+
+	for (i = 0; i < len / 2; i++)
+		sum += words[i];
+	if (len & 1)
+		sum += ((char *)data)[len - 1];
+	return sum;
+}
+
+static uint16_t checksum_fold(void *data, size_t len, uint32_t sum)
+{
+	sum = checksum_nofold(data, len, sum);
+	while (sum > 0xFFFF)
+		sum = (sum & 0xFFFF) + (sum >> 16);
+	return ~sum;
+}
+
+static uint16_t tcp_checksum(void *buf, int payload_len)
+{
+	struct pseudo_header6 {
+		struct in6_addr saddr;
+		struct in6_addr daddr;
+		uint16_t protocol;
+		uint16_t payload_len;
+	} ph6;
+	struct pseudo_header4 {
+		struct in_addr saddr;
+		struct in_addr daddr;
+		uint16_t protocol;
+		uint16_t payload_len;
+	} ph4;
+	uint32_t sum = 0;
+
+	if (proto == PF_INET6) {
+		if (inet_pton(AF_INET6, SIP6, &ph6.saddr) != 1)
+			error(1, errno, "inet_pton6 source ip pseudo");
+		if (inet_pton(AF_INET6, DIP6, &ph6.daddr) != 1)
+			error(1, errno, "inet_pton6 dest ip pseudo");
+		ph6.protocol = htons(IPPROTO_TCP);
+		ph6.payload_len = htons(sizeof(struct tcphdr) + payload_len);
+
+		sum = checksum_nofold(&ph6, sizeof(ph6), 0);
+	} else if (proto == PF_INET) {
+		if (inet_pton(AF_INET, SIP4, &ph4.saddr) != 1)
+			error(1, errno, "inet_pton source ip pseudo");
+		if (inet_pton(AF_INET, DIP4, &ph4.daddr) != 1)
+			error(1, errno, "inet_pton dest ip pseudo");
+		ph4.protocol = htons(IPPROTO_TCP);
+		ph4.payload_len = htons(sizeof(struct tcphdr) + payload_len);
+
+		sum = checksum_nofold(&ph4, sizeof(ph4), 0);
+	}
+
+	return checksum_fold(buf, sizeof(struct tcphdr) + payload_len, sum);
+}
+
+static void read_MAC(uint8_t *mac_addr, char *mac)
+{
+	if (sscanf(mac, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
+		   &mac_addr[0], &mac_addr[1], &mac_addr[2],
+		   &mac_addr[3], &mac_addr[4], &mac_addr[5]) != 6)
+		error(1, 0, "sscanf");
+}
+
+static void fill_datalinklayer(void *buf)
+{
+	struct ethhdr *eth = buf;
+
+	memcpy(eth->h_dest, dst_mac, ETH_ALEN);
+	memcpy(eth->h_source, src_mac, ETH_ALEN);
+	eth->h_proto = ethhdr_proto;
+}
+
+static void fill_networklayer(void *buf, int payload_len)
+{
+	struct ipv6hdr *ip6h = buf;
+	struct iphdr *iph = buf;
+
+	if (proto == PF_INET6) {
+		memset(ip6h, 0, sizeof(*ip6h));
+
+		ip6h->version = 6;
+		ip6h->payload_len = htons(sizeof(struct tcphdr) + payload_len);
+		ip6h->nexthdr = IPPROTO_TCP;
+		ip6h->hop_limit = 8;
+		if (inet_pton(AF_INET6, SIP6, &ip6h->saddr) != 1)
+			error(1, errno, "inet_pton source ip6");
+		if (inet_pton(AF_INET6, DIP6, &ip6h->daddr) != 1)
+			error(1, errno, "inet_pton dest ip6");
+	} else if (proto == PF_INET) {
+		memset(iph, 0, sizeof(*iph));
+
+		iph->version = 4;
+		iph->ihl = 5;
+		iph->ttl = 8;
+		iph->protocol	= IPPROTO_TCP;
+		iph->tot_len = htons(sizeof(struct tcphdr) +
+				payload_len + sizeof(struct iphdr));
+		iph->frag_off = htons(0x4000); /* DF = 1, MF = 0 */
+		if (inet_pton(AF_INET, SIP4, &iph->saddr) != 1)
+			error(1, errno, "inet_pton source ip");
+		if (inet_pton(AF_INET, DIP4, &iph->daddr) != 1)
+			error(1, errno, "inet_pton dest ip");
+		iph->check = checksum_fold(buf, sizeof(struct iphdr), 0);
+	}
+}
+
+static void fill_transportlayer(void *buf, int seq_offset, int ack_offset,
+				int payload_len, int fin)
+{
+	struct tcphdr *tcph = buf;
+
+	memset(tcph, 0, sizeof(*tcph));
+
+	tcph->source = htons(SPORT);
+	tcph->dest = htons(DPORT);
+	tcph->seq = ntohl(START_SEQ + seq_offset);
+	tcph->ack_seq = ntohl(START_ACK + ack_offset);
+	tcph->ack = 1;
+	tcph->fin = fin;
+	tcph->doff = 5;
+	tcph->window = htons(TCP_MAXWIN);
+	tcph->urg_ptr = 0;
+	tcph->check = tcp_checksum(tcph, payload_len);
+}
+
+static void write_packet(int fd, char *buf, int len, struct sockaddr_ll *daddr)
+{
+	int ret = -1;
+
+	ret = sendto(fd, buf, len, 0, (struct sockaddr *)daddr, sizeof(*daddr));
+	if (ret == -1)
+		error(1, errno, "sendto failure");
+	if (ret != len)
+		error(1, errno, "sendto wrong length");
+}
+
+static void create_packet(void *buf, int seq_offset, int ack_offset,
+			  int payload_len, int fin)
+{
+	memset(buf, 0, total_hdr_len);
+	memset(buf + total_hdr_len, 'a', payload_len);
+	fill_transportlayer(buf + tcp_offset, seq_offset, ack_offset,
+			    payload_len, fin);
+	fill_networklayer(buf + ETH_HLEN, payload_len);
+	fill_datalinklayer(buf);
+}
+
+/* send one extra flag, not first and not last pkt */
+static void send_flags(int fd, struct sockaddr_ll *daddr, int psh, int syn,
+		       int rst, int urg)
+{
+	static char flag_buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	int payload_len, pkt_size, flag, i;
+	struct tcphdr *tcph;
+
+	payload_len = PAYLOAD_LEN * psh;
+	pkt_size = total_hdr_len + payload_len;
+	flag = NUM_PACKETS / 2;
+
+	create_packet(flag_buf, flag * payload_len, 0, payload_len, 0);
+
+	tcph = (struct tcphdr *)(flag_buf + tcp_offset);
+	tcph->psh = psh;
+	tcph->syn = syn;
+	tcph->rst = rst;
+	tcph->urg = urg;
+	tcph->check = 0;
+	tcph->check = tcp_checksum(tcph, payload_len);
+
+	for (i = 0; i < NUM_PACKETS + 1; i++) {
+		if (i == flag) {
+			write_packet(fd, flag_buf, pkt_size, daddr);
+			continue;
+		}
+		create_packet(buf, i * PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+		write_packet(fd, buf, total_hdr_len + PAYLOAD_LEN, daddr);
+	}
+}
+
+/* Test for data of same length, smaller than previous
+ * and of different lengths
+ */
+static void send_data_pkts(int fd, struct sockaddr_ll *daddr,
+			   int payload_len1, int payload_len2)
+{
+	static char buf[ETH_HLEN + IP_MAXPACKET];
+
+	create_packet(buf, 0, 0, payload_len1, 0);
+	write_packet(fd, buf, total_hdr_len + payload_len1, daddr);
+	create_packet(buf, payload_len1, 0, payload_len2, 0);
+	write_packet(fd, buf, total_hdr_len + payload_len2, daddr);
+}
+
+/* If incoming segments make tracked segment length exceed
+ * legal IP datagram length, do not coalesce
+ */
+static void send_large(int fd, struct sockaddr_ll *daddr, int remainder)
+{
+	static char pkts[NUM_LARGE_PKT][TOTAL_HDR_LEN + MSS];
+	static char last[TOTAL_HDR_LEN + MSS];
+	static char new_seg[TOTAL_HDR_LEN + MSS];
+	int i;
+
+	for (i = 0; i < NUM_LARGE_PKT; i++)
+		create_packet(pkts[i], i * MSS, 0, MSS, 0);
+	create_packet(last, NUM_LARGE_PKT * MSS, 0, remainder, 0);
+	create_packet(new_seg, (NUM_LARGE_PKT + 1) * MSS, 0, remainder, 0);
+
+	for (i = 0; i < NUM_LARGE_PKT; i++)
+		write_packet(fd, pkts[i], total_hdr_len + MSS, daddr);
+	write_packet(fd, last, total_hdr_len + remainder, daddr);
+	write_packet(fd, new_seg, total_hdr_len + remainder, daddr);
+}
+
+/* Pure acks and dup acks don't coalesce */
+static void send_ack(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN];
+
+	create_packet(buf, 0, 0, 0, 0);
+	write_packet(fd, buf, total_hdr_len, daddr);
+	write_packet(fd, buf, total_hdr_len, daddr);
+	create_packet(buf, 0, 1, 0, 0);
+	write_packet(fd, buf, total_hdr_len, daddr);
+}
+
+static void recompute_packet(char *buf, char *no_ext, int extlen)
+{
+	struct tcphdr *tcphdr = (struct tcphdr *)(buf + tcp_offset);
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buf + ETH_HLEN);
+	struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+
+	memmove(buf, no_ext, total_hdr_len);
+	memmove(buf + total_hdr_len + extlen,
+		no_ext + total_hdr_len, PAYLOAD_LEN);
+
+	tcphdr->doff = tcphdr->doff + (extlen / 4);
+	tcphdr->check = 0;
+	tcphdr->check = tcp_checksum(tcphdr, PAYLOAD_LEN + extlen);
+	if (proto == PF_INET) {
+		iph->tot_len = htons(ntohs(iph->tot_len) + extlen);
+		iph->check = 0;
+		iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+	} else {
+		ip6h->payload_len = htons(ntohs(ip6h->payload_len) + extlen);
+	}
+}
+
+static void tcp_write_options(char *buf, int kind, int ts)
+{
+	struct tcp_option_ts {
+		uint8_t kind;
+		uint8_t len;
+		uint32_t tsval;
+		uint32_t tsecr;
+	} *opt_ts = (void *)buf;
+	struct tcp_option_window {
+		uint8_t kind;
+		uint8_t len;
+		uint8_t shift;
+	} *opt_window = (void *)buf;
+
+	switch (kind) {
+	case TCPOPT_NOP:
+		buf[0] = TCPOPT_NOP;
+		break;
+	case TCPOPT_WINDOW:
+		memset(opt_window, 0, sizeof(struct tcp_option_window));
+		opt_window->kind = TCPOPT_WINDOW;
+		opt_window->len = TCPOLEN_WINDOW;
+		opt_window->shift = 0;
+		break;
+	case TCPOPT_TIMESTAMP:
+		memset(opt_ts, 0, sizeof(struct tcp_option_ts));
+		opt_ts->kind = TCPOPT_TIMESTAMP;
+		opt_ts->len = TCPOLEN_TIMESTAMP;
+		opt_ts->tsval = ts;
+		opt_ts->tsecr = 0;
+		break;
+	default:
+		error(1, 0, "unimplemented TCP option");
+		break;
+	}
+}
+
+/* TCP with options is always a permutation of {TS, NOP, NOP}.
+ * Implement different orders to verify coalescing stops.
+ */
+static void add_standard_tcp_options(char *buf, char *no_ext, int ts, int order)
+{
+	switch (order) {
+	case 0:
+		tcp_write_options(buf + total_hdr_len, TCPOPT_NOP, 0);
+		tcp_write_options(buf + total_hdr_len + 1, TCPOPT_NOP, 0);
+		tcp_write_options(buf + total_hdr_len + 2 /* two NOP opts */,
+				  TCPOPT_TIMESTAMP, ts);
+		break;
+	case 1:
+		tcp_write_options(buf + total_hdr_len, TCPOPT_NOP, 0);
+		tcp_write_options(buf + total_hdr_len + 1,
+				  TCPOPT_TIMESTAMP, ts);
+		tcp_write_options(buf + total_hdr_len + 1 + TCPOLEN_TIMESTAMP,
+				  TCPOPT_NOP, 0);
+		break;
+	case 2:
+		tcp_write_options(buf + total_hdr_len, TCPOPT_TIMESTAMP, ts);
+		tcp_write_options(buf + total_hdr_len + TCPOLEN_TIMESTAMP + 1,
+				  TCPOPT_NOP, 0);
+		tcp_write_options(buf + total_hdr_len + TCPOLEN_TIMESTAMP + 2,
+				  TCPOPT_NOP, 0);
+		break;
+	default:
+		error(1, 0, "unknown order");
+		break;
+	}
+	recompute_packet(buf, no_ext, TCPOLEN_TSTAMP_APPA);
+}
+
+/* Packets with invalid checksum don't coalesce. */
+static void send_changed_checksum(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	struct tcphdr *tcph = (struct tcphdr *)(buf + tcp_offset);
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	tcph->check = tcph->check - 1;
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
+ /* Packets with non-consecutive sequence number don't coalesce.*/
+static void send_changed_seq(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	struct tcphdr *tcph = (struct tcphdr *)(buf + tcp_offset);
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	tcph->seq = ntohl(htonl(tcph->seq) + 1);
+	tcph->check = 0;
+	tcph->check = tcp_checksum(tcph, PAYLOAD_LEN);
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
+ /* Packet with different timestamp option or different timestamps
+  * don't coalesce.
+  */
+static void send_changed_ts(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	static char extpkt[sizeof(buf) + TCPOLEN_TSTAMP_APPA];
+	int pkt_size = total_hdr_len + PAYLOAD_LEN + TCPOLEN_TSTAMP_APPA;
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt, buf, 0, 0);
+	write_packet(fd, extpkt, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt, buf, 0, 0);
+	write_packet(fd, extpkt, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt, buf, 100, 0);
+	write_packet(fd, extpkt, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 3, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt, buf, 100, 1);
+	write_packet(fd, extpkt, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 4, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt, buf, 100, 2);
+	write_packet(fd, extpkt, pkt_size, daddr);
+}
+
+/* Packet with different tcp options don't coalesce. */
+static void send_diff_opt(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	static char extpkt1[sizeof(buf) + TCPOLEN_TSTAMP_APPA];
+	static char extpkt2[sizeof(buf) + TCPOLEN_MAXSEG];
+	int extpkt1_size = total_hdr_len + PAYLOAD_LEN + TCPOLEN_TSTAMP_APPA;
+	int extpkt2_size = total_hdr_len + PAYLOAD_LEN + TCPOLEN_MAXSEG;
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt1, buf, 0, 0);
+	write_packet(fd, extpkt1, extpkt1_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	add_standard_tcp_options(extpkt1, buf, 0, 0);
+	write_packet(fd, extpkt1, extpkt1_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+	tcp_write_options(extpkt2 + MAX_HDR_LEN, TCPOPT_NOP, 0);
+	tcp_write_options(extpkt2 + MAX_HDR_LEN + 1, TCPOPT_WINDOW, 0);
+	recompute_packet(extpkt2, buf, TCPOLEN_WINDOW + 1);
+	write_packet(fd, extpkt2, extpkt2_size, daddr);
+}
+
+static void add_ipv4_ts_option(void *buf, void *optpkt)
+{
+	struct ip_timestamp *ts = (struct ip_timestamp *)(optpkt + tcp_offset);
+	int optlen = sizeof(struct ip_timestamp);
+	struct iphdr *iph;
+
+	if (optlen % 4)
+		error(1, 0, "ipv4 timestamp length is not a multiple of 4B");
+
+	ts->ipt_code = IPOPT_TS;
+	ts->ipt_len = optlen;
+	ts->ipt_ptr = 5;
+	ts->ipt_flg = IPOPT_TS_TSONLY;
+
+	memcpy(optpkt, buf, tcp_offset);
+	memcpy(optpkt + tcp_offset + optlen, buf + tcp_offset,
+	       sizeof(struct tcphdr) + PAYLOAD_LEN);
+
+	iph = (struct iphdr *)(optpkt + ETH_HLEN);
+	iph->ihl = 5 + (optlen / 4);
+	iph->tot_len = htons(ntohs(iph->tot_len) + optlen);
+	iph->check = 0;
+	iph->check = checksum_fold(iph, sizeof(struct iphdr) + optlen, 0);
+}
+
+/* IPv4 options shouldn't coalesce */
+static void send_ip_options(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	static char optpkt[sizeof(buf) + sizeof(struct ip_timestamp)];
+	int optlen = sizeof(struct ip_timestamp);
+	int pkt_size = total_hdr_len + PAYLOAD_LEN + optlen;
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, total_hdr_len + PAYLOAD_LEN, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 1, 0, PAYLOAD_LEN, 0);
+	add_ipv4_ts_option(buf, optpkt);
+	write_packet(fd, optpkt, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, total_hdr_len + PAYLOAD_LEN, daddr);
+}
+
+/*  IPv4 fragments shouldn't coalesce */
+static void send_fragment4(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[IP_MAXPACKET];
+	struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	/* Once fragmented, packet would retain the total_len.
+	 * Tcp header is prepared as if rest of data is in follow-up frags,
+	 * but follow up frags aren't actually sent.
+	 */
+	memset(buf + total_hdr_len, 'a', PAYLOAD_LEN * 2);
+	fill_transportlayer(buf + tcp_offset, PAYLOAD_LEN, 0, PAYLOAD_LEN * 2, 0);
+	fill_networklayer(buf + ETH_HLEN, PAYLOAD_LEN);
+	fill_datalinklayer(buf);
+
+	iph->frag_off = htons(0x6000); // DF = 1, MF = 1
+	iph->check = 0;
+	iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* IPv4 packets with different ttl don't coalesce.*/
+static void send_changed_ttl(int fd, struct sockaddr_ll *daddr)
+{
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	iph->ttl = 7;
+	iph->check = 0;
+	iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* Packets with different tos don't coalesce.*/
+static void send_changed_tos(int fd, struct sockaddr_ll *daddr)
+{
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buf + ETH_HLEN);
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	if (proto == PF_INET) {
+		iph->tos = 1;
+		iph->check = 0;
+		iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+	} else if (proto == PF_INET6) {
+		ip6h->priority = 0xf;
+	}
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* Packets with different ECN don't coalesce.*/
+static void send_changed_ECN(int fd, struct sockaddr_ll *daddr)
+{
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	struct iphdr *iph = (struct iphdr *)(buf + ETH_HLEN);
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	if (proto == PF_INET) {
+		buf[ETH_HLEN + 1] ^= 0x2; // ECN set to 10
+		iph->check = 0;
+		iph->check = checksum_fold(iph, sizeof(struct iphdr), 0);
+	} else {
+		buf[ETH_HLEN + 1] ^= 0x20; // ECN set to 10
+	}
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
+/* IPv6 fragments and packets with extensions don't coalesce.*/
+static void send_fragment6(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	static char extpkt[MAX_HDR_LEN + PAYLOAD_LEN +
+			   sizeof(struct ip6_frag)];
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buf + ETH_HLEN);
+	struct ip6_frag *frag = (void *)(extpkt + tcp_offset);
+	int extlen = sizeof(struct ip6_frag);
+	int bufpkt_len = total_hdr_len + PAYLOAD_LEN;
+	int extpkt_len = bufpkt_len + extlen;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		create_packet(buf, PAYLOAD_LEN * i, 0, PAYLOAD_LEN, 0);
+		write_packet(fd, buf, bufpkt_len, daddr);
+	}
+
+	create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+	memset(extpkt, 0, extpkt_len);
+
+	ip6h->nexthdr = IPPROTO_FRAGMENT;
+	ip6h->payload_len = htons(ntohs(ip6h->payload_len) + extlen);
+	frag->ip6f_nxt = IPPROTO_TCP;
+
+	memcpy(extpkt, buf, tcp_offset);
+	memcpy(extpkt + tcp_offset + extlen, buf + tcp_offset,
+	       sizeof(struct tcphdr) + PAYLOAD_LEN);
+	write_packet(fd, extpkt, extpkt_len, daddr);
+
+	create_packet(buf, PAYLOAD_LEN * 3, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, bufpkt_len, daddr);
+}
+
+static void bind_packetsocket(int fd)
+{
+	struct sockaddr_ll daddr = {};
+
+	daddr.sll_family = AF_PACKET;
+	daddr.sll_protocol = ethhdr_proto;
+	daddr.sll_ifindex = if_nametoindex(ifname);
+	if (daddr.sll_ifindex == 0)
+		error(1, errno, "if_nametoindex");
+
+	if (bind(fd, (void *)&daddr, sizeof(daddr)) < 0)
+		error(1, errno, "could not bind socket");
+}
+
+static void set_timeout(int fd)
+{
+	struct timeval timeout;
+
+	timeout.tv_sec = 120;
+	timeout.tv_usec = 0;
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout,
+		       sizeof(timeout)) < 0)
+		error(1, errno, "cannot set timeout, setsockopt failed");
+}
+
+static void check_recv_pkts(int fd, int *correct_payload,
+			    int correct_num_pkts)
+{
+	static char buffer[IP_MAXPACKET + ETH_HLEN + 1];
+	struct iphdr *iph = (struct iphdr *)(buffer + ETH_HLEN);
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + ETH_HLEN);
+	struct tcphdr *tcph;
+	bool bad_packet = false;
+	int tcp_ext_len = 0;
+	int ip_ext_len = 0;
+	int pkt_size = -1;
+	int data_len = 0;
+	int num_pkt = 0;
+	int i;
+
+	vlog("Expected {");
+	for (i = 0; i < correct_num_pkts; i++)
+		vlog("%d ", correct_payload[i]);
+	vlog("}, Total %d packets\nReceived {", correct_num_pkts);
+
+	while (1) {
+		pkt_size = recv(fd, buffer, IP_MAXPACKET + ETH_HLEN + 1, 0);
+		if (pkt_size < 0)
+			error(1, errno, "could not receive");
+
+		if (iph->version == 4)
+			ip_ext_len = (iph->ihl - 5) * 4;
+		else if (ip6h->version == 6 && ip6h->nexthdr != IPPROTO_TCP)
+			ip_ext_len = sizeof(struct ip6_frag);
+
+		tcph = (struct tcphdr *)(buffer + tcp_offset + ip_ext_len);
+
+		if (tcph->fin)
+			break;
+
+		tcp_ext_len = (tcph->doff - 5) * 4;
+		data_len = pkt_size - total_hdr_len - tcp_ext_len - ip_ext_len;
+		/* Min ethernet frame payload is 46(ETH_ZLEN - ETH_HLEN) by RFC 802.3.
+		 * Ipv4/tcp packets without at least 6 bytes of data will be padded.
+		 * Packet sockets are protocol agnostic, and will not trim the padding.
+		 */
+		if (pkt_size == ETH_ZLEN && iph->version == 4) {
+			data_len = ntohs(iph->tot_len)
+				- sizeof(struct tcphdr) - sizeof(struct iphdr);
+		}
+		vlog("%d ", data_len);
+		if (data_len != correct_payload[num_pkt]) {
+			vlog("[!=%d]", correct_payload[num_pkt]);
+			bad_packet = true;
+		}
+		num_pkt++;
+	}
+	vlog("}, Total %d packets.\n", num_pkt);
+	if (num_pkt != correct_num_pkts)
+		error(1, 0, "incorrect number of packets");
+	if (bad_packet)
+		error(1, 0, "incorrect packet geometry");
+
+	printf("Test succeeded\n\n");
+}
+
+static void gro_sender(void)
+{
+	static char fin_pkt[MAX_HDR_LEN];
+	struct sockaddr_ll daddr = {};
+	int txfd = -1;
+
+	txfd = socket(PF_PACKET, SOCK_RAW, IPPROTO_RAW);
+	if (txfd < 0)
+		error(1, errno, "socket creation");
+
+	memset(&daddr, 0, sizeof(daddr));
+	daddr.sll_ifindex = if_nametoindex(ifname);
+	if (daddr.sll_ifindex == 0)
+		error(1, errno, "if_nametoindex");
+	daddr.sll_family = AF_PACKET;
+	memcpy(daddr.sll_addr, dst_mac, ETH_ALEN);
+	daddr.sll_halen = ETH_ALEN;
+	create_packet(fin_pkt, PAYLOAD_LEN * 2, 0, 0, 1);
+
+	if (strcmp(testname, "data") == 0) {
+		send_data_pkts(txfd, &daddr, PAYLOAD_LEN, PAYLOAD_LEN);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_data_pkts(txfd, &daddr, PAYLOAD_LEN, PAYLOAD_LEN / 2);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_data_pkts(txfd, &daddr, PAYLOAD_LEN / 2, PAYLOAD_LEN);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+	} else if (strcmp(testname, "ack") == 0) {
+		send_ack(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+	} else if (strcmp(testname, "flags") == 0) {
+		send_flags(txfd, &daddr, 1, 0, 0, 0);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_flags(txfd, &daddr, 0, 1, 0, 0);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_flags(txfd, &daddr, 0, 0, 1, 0);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_flags(txfd, &daddr, 0, 0, 0, 1);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+	} else if (strcmp(testname, "tcp") == 0) {
+		send_changed_checksum(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_changed_seq(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_changed_ts(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_diff_opt(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+	} else if (strcmp(testname, "ip") == 0) {
+		send_changed_ECN(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_changed_tos(txfd, &daddr);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+		if (proto == PF_INET) {
+			/* Modified packets may be received out of order.
+			 * Sleep function added to enforce test boundaries
+			 * so that fin pkts are not received prior to other pkts.
+			 */
+			sleep(1);
+			send_changed_ttl(txfd, &daddr);
+			write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+			sleep(1);
+			send_ip_options(txfd, &daddr);
+			sleep(1);
+			write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+			sleep(1);
+			send_fragment4(txfd, &daddr);
+			sleep(1);
+			write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+		} else if (proto == PF_INET6) {
+			send_fragment6(txfd, &daddr);
+			write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+		}
+	} else if (strcmp(testname, "large") == 0) {
+		/* 20 is the difference between min iphdr size
+		 * and min ipv6hdr size. Like MAX_HDR_SIZE,
+		 * MAX_PAYLOAD is defined with the larger header of the two.
+		 */
+		int offset = proto == PF_INET ? 20 : 0;
+		int remainder = (MAX_PAYLOAD + offset) % MSS;
+
+		send_large(txfd, &daddr, remainder);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+		send_large(txfd, &daddr, remainder + 1);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+	} else {
+		error(1, 0, "Unknown testcase");
+	}
+
+	if (close(txfd))
+		error(1, errno, "socket close");
+}
+
+static void gro_receiver(void)
+{
+	static int correct_payload[NUM_PACKETS];
+	int rxfd = -1;
+
+	rxfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_NONE));
+	if (rxfd < 0)
+		error(1, 0, "socket creation");
+	setup_sock_filter(rxfd);
+	set_timeout(rxfd);
+	bind_packetsocket(rxfd);
+
+	memset(correct_payload, 0, sizeof(correct_payload));
+
+	if (strcmp(testname, "data") == 0) {
+		printf("pure data packet of same size: ");
+		correct_payload[0] = PAYLOAD_LEN * 2;
+		check_recv_pkts(rxfd, correct_payload, 1);
+
+		printf("large data packets followed by a smaller one: ");
+		correct_payload[0] = PAYLOAD_LEN * 1.5;
+		check_recv_pkts(rxfd, correct_payload, 1);
+
+		printf("small data packets followed by a larger one: ");
+		correct_payload[0] = PAYLOAD_LEN / 2;
+		correct_payload[1] = PAYLOAD_LEN;
+		check_recv_pkts(rxfd, correct_payload, 2);
+	} else if (strcmp(testname, "ack") == 0) {
+		printf("duplicate ack and pure ack: ");
+		check_recv_pkts(rxfd, correct_payload, 3);
+	} else if (strcmp(testname, "flags") == 0) {
+		correct_payload[0] = PAYLOAD_LEN * 3;
+		correct_payload[1] = PAYLOAD_LEN * 2;
+
+		printf("psh flag ends coalescing: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
+		correct_payload[0] = PAYLOAD_LEN * 2;
+		correct_payload[1] = 0;
+		correct_payload[2] = PAYLOAD_LEN * 2;
+		printf("syn flag ends coalescing: ");
+		check_recv_pkts(rxfd, correct_payload, 3);
+
+		printf("rst flag ends coalescing: ");
+		check_recv_pkts(rxfd, correct_payload, 3);
+
+		printf("urg flag ends coalescing: ");
+		check_recv_pkts(rxfd, correct_payload, 3);
+	} else if (strcmp(testname, "tcp") == 0) {
+		correct_payload[0] = PAYLOAD_LEN;
+		correct_payload[1] = PAYLOAD_LEN;
+		correct_payload[2] = PAYLOAD_LEN;
+		correct_payload[3] = PAYLOAD_LEN;
+
+		printf("changed checksum does not coalesce: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
+		printf("Wrong Seq number doesn't coalesce: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
+		printf("Different timestamp doesn't coalesce: ");
+		correct_payload[0] = PAYLOAD_LEN * 2;
+		check_recv_pkts(rxfd, correct_payload, 4);
+
+		printf("Different options doesn't coalesce: ");
+		correct_payload[0] = PAYLOAD_LEN * 2;
+		check_recv_pkts(rxfd, correct_payload, 2);
+	} else if (strcmp(testname, "ip") == 0) {
+		correct_payload[0] = PAYLOAD_LEN;
+		correct_payload[1] = PAYLOAD_LEN;
+
+		printf("different ECN doesn't coalesce: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
+		printf("different tos doesn't coalesce: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
+		if (proto == PF_INET) {
+			printf("different ttl doesn't coalesce: ");
+			check_recv_pkts(rxfd, correct_payload, 2);
+
+			printf("ip options doesn't coalesce: ");
+			correct_payload[2] = PAYLOAD_LEN;
+			check_recv_pkts(rxfd, correct_payload, 3);
+
+			printf("fragmented ip4 doesn't coalesce: ");
+			check_recv_pkts(rxfd, correct_payload, 2);
+		} else if (proto == PF_INET6) {
+			/* GRO doesn't check for ipv6 hop limit when flushing.
+			 * Hence no corresponding test to the ipv4 case.
+			 */
+			printf("fragmented ip6 doesn't coalesce: ");
+			correct_payload[0] = PAYLOAD_LEN * 2;
+			check_recv_pkts(rxfd, correct_payload, 2);
+		}
+	} else if (strcmp(testname, "large") == 0) {
+		int offset = proto == PF_INET ? 20 : 0;
+		int remainder = (MAX_PAYLOAD + offset) % MSS;
+
+		correct_payload[0] = (MAX_PAYLOAD + offset);
+		correct_payload[1] = remainder;
+		printf("Shouldn't coalesce if exceed IP max pkt size: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
+		/* last segment sent individually, doesn't start new segment */
+		correct_payload[0] = correct_payload[0] - remainder;
+		correct_payload[1] = remainder + 1;
+		correct_payload[2] = remainder + 1;
+		check_recv_pkts(rxfd, correct_payload, 3);
+	} else {
+		error(1, 0, "Test case error, should never trigger");
+	}
+
+	if (close(rxfd))
+		error(1, 0, "socket close");
+}
+
+static void parse_args(int argc, char **argv)
+{
+	static const struct option opts[] = {
+		{ "dmac", required_argument, NULL, 'D' },
+		{ "iface", required_argument, NULL, 'i' },
+		{ "ipv4", no_argument, NULL, '4' },
+		{ "ipv6", no_argument, NULL, '6' },
+		{ "rx", no_argument, NULL, 'r' },
+		{ "smac", required_argument, NULL, 'S' },
+		{ "test", required_argument, NULL, 't' },
+		{ "verbose", no_argument, NULL, 'v' },
+		{ 0, 0, 0, 0 }
+	};
+	int c;
+
+	while ((c = getopt_long(argc, argv, "46D:i:rS:t:v", opts, NULL)) != -1) {
+		switch (c) {
+		case '4':
+			proto = PF_INET;
+			ethhdr_proto = htons(ETH_P_IP);
+			break;
+		case '6':
+			proto = PF_INET6;
+			ethhdr_proto = htons(ETH_P_IPV6);
+			break;
+		case 'D':
+			dmac = optarg;
+			break;
+		case 'i':
+			ifname = optarg;
+			break;
+		case 'r':
+			tx_socket = false;
+			break;
+		case 'S':
+			smac = optarg;
+			break;
+		case 't':
+			testname = optarg;
+			break;
+		case 'v':
+			verbose = true;
+			break;
+		default:
+			error(1, 0, "%s invalid option %c\n", __func__, c);
+			break;
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	parse_args(argc, argv);
+
+	if (proto == PF_INET) {
+		tcp_offset = ETH_HLEN + sizeof(struct iphdr);
+		total_hdr_len = tcp_offset + sizeof(struct tcphdr);
+	} else if (proto == PF_INET6) {
+		tcp_offset = ETH_HLEN + sizeof(struct ipv6hdr);
+		total_hdr_len = MAX_HDR_LEN;
+	} else {
+		error(1, 0, "Protocol family is not ipv4 or ipv6");
+	}
+
+	read_MAC(src_mac, smac);
+	read_MAC(dst_mac, dmac);
+
+	if (tx_socket)
+		gro_sender();
+	else
+		gro_receiver();
+	return 0;
+}

tools/testing/selftests/net/gro.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source setup_loopback.sh
+readonly SERVER_MAC="aa:00:00:00:00:02"
+readonly CLIENT_MAC="aa:00:00:00:00:01"
+readonly TESTS=("data" "ack" "flags" "tcp" "ip" "large")
+readonly PROTOS=("ipv4" "ipv6")
+dev="eth0"
+test="all"
+proto="ipv4"
+
+setup_interrupt() {
+  # Use timer on  host to trigger the network stack
+  # Also disable device interrupt to not depend on NIC interrupt
+  # Reduce test flakiness caused by unexpected interrupts
+  echo 100000 >"${FLUSH_PATH}"
+  echo 50 >"${IRQ_PATH}"
+}
+
+setup_ns() {
+  # Set up server_ns namespace and client_ns namespace
+  setup_macvlan_ns "${dev}" server_ns server "${SERVER_MAC}"
+  setup_macvlan_ns "${dev}" client_ns client "${CLIENT_MAC}"
+}
+
+cleanup_ns() {
+  cleanup_macvlan_ns server_ns server client_ns client
+}
+
+setup() {
+  setup_loopback_environment "${dev}"
+  setup_interrupt
+}
+
+cleanup() {
+  cleanup_loopback "${dev}"
+
+  echo "${FLUSH_TIMEOUT}" >"${FLUSH_PATH}"
+  echo "${HARD_IRQS}" >"${IRQ_PATH}"
+}
+
+run_test() {
+  local server_pid=0
+  local exit_code=0
+  local protocol=$1
+  local test=$2
+  local ARGS=( "--${protocol}" "--dmac" "${SERVER_MAC}" \
+  "--smac" "${CLIENT_MAC}" "--test" "${test}" "--verbose" )
+
+  setup_ns
+  # Each test is run 3 times to deflake, because given the receive timing,
+  # not all packets that should coalesce will be considered in the same flow
+  # on every try.
+  for tries in {1..3}; do
+    # Actual test starts here
+    ip netns exec server_ns ./gro "${ARGS[@]}" "--rx" "--iface" "server" \
+      1>>log.txt &
+    server_pid=$!
+    sleep 0.5  # to allow for socket init
+    ip netns exec client_ns ./gro "${ARGS[@]}" "--iface" "client" \
+      1>>log.txt
+    wait "${server_pid}"
+    exit_code=$?
+    if [[ "${exit_code}" -eq 0 ]]; then
+        break;
+    fi
+  done
+  cleanup_ns
+  echo ${exit_code}
+}
+
+run_all_tests() {
+  local failed_tests=()
+  for proto in "${PROTOS[@]}"; do
+    for test in "${TESTS[@]}"; do
+      echo "running test ${proto} ${test}" >&2
+      exit_code=$(run_test $proto $test)
+      if [[ "${exit_code}" -ne 0 ]]; then
+        failed_tests+=("${proto}_${test}")
+      fi;
+    done;
+  done
+  if [[ ${#failed_tests[@]} -ne 0 ]]; then
+    echo "failed tests: ${failed_tests[*]}. \
+    Please see log.txt for more logs"
+    exit 1
+  else
+    echo "All Tests Succeeded!"
+  fi;
+}
+
+usage() {
+  echo "Usage: $0 \
+  [-i <DEV>] \
+  [-t data|ack|flags|tcp|ip|large] \
+  [-p <ipv4|ipv6>]" 1>&2;
+  exit 1;
+}
+
+while getopts "i:t:p:" opt; do
+  case "${opt}" in
+    i)
+      dev="${OPTARG}"
+      ;;
+    t)
+      test="${OPTARG}"
+      ;;
+    p)
+      proto="${OPTARG}"
+      ;;
+    *)
+      usage
+      ;;
+  esac
+done
+
+readonly FLUSH_PATH="/sys/class/net/${dev}/gro_flush_timeout"
+readonly IRQ_PATH="/sys/class/net/${dev}/napi_defer_hard_irqs"
+readonly FLUSH_TIMEOUT="$(< ${FLUSH_PATH})"
+readonly HARD_IRQS="$(< ${IRQ_PATH})"
+setup
+trap cleanup EXIT
+if [[ "${test}" == "all" ]]; then
+  run_all_tests
+else
+  run_test "${proto}" "${test}"
+fi;

tools/testing/selftests/net/setup_loopback.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+netdev_check_for_carrier() {
+	local -r dev="$1"
+
+	for i in {1..5}; do
+		carrier="$(cat /sys/class/net/${dev}/carrier)"
+		if [[ "${carrier}" -ne 1 ]] ; then
+			echo "carrier not ready yet..." >&2
+			sleep 1
+		else
+			echo "carrier ready" >&2
+			break
+		fi
+	done
+	echo "${carrier}"
+}
+
+# Assumes that there is no existing ipvlan device on the physical device
+setup_loopback_environment() {
+    local dev="$1"
+
+	# Fail hard if cannot turn on loopback mode for current NIC
+	ethtool -K "${dev}" loopback on || exit 1
+	sleep 1
+
+	# Check for the carrier
+	carrier=$(netdev_check_for_carrier ${dev})
+	if [[ "${carrier}" -ne 1 ]] ; then
+		echo "setup_loopback_environment failed"
+		exit 1
+	fi
+}
+
+setup_macvlan_ns(){
+	local -r link_dev="$1"
+	local -r ns_name="$2"
+	local -r ns_dev="$3"
+	local -r ns_mac="$4"
+	local -r addr="$5"
+
+	ip link add link "${link_dev}" dev "${ns_dev}" \
+		address "${ns_mac}" type macvlan
+	exit_code=$?
+	if [[ "${exit_code}" -ne 0 ]]; then
+		echo "setup_macvlan_ns failed"
+		exit $exit_code
+	fi
+
+	[[ -e /var/run/netns/"${ns_name}" ]] || ip netns add "${ns_name}"
+	ip link set dev "${ns_dev}" netns "${ns_name}"
+	ip -netns "${ns_name}" link set dev "${ns_dev}" up
+	if [[ -n "${addr}" ]]; then
+		ip -netns "${ns_name}" addr add dev "${ns_dev}" "${addr}"
+	fi
+
+	sleep 1
+}
+
+cleanup_macvlan_ns(){
+	while (( $# >= 2 )); do
+		ns_name="$1"
+		ns_dev="$2"
+		ip -netns "${ns_name}" link del dev "${ns_dev}"
+		ip netns del "${ns_name}"
+		shift 2
+	done
+}
+
+cleanup_loopback(){
+	local -r dev="$1"
+
+	ethtool -K "${dev}" loopback off
+	sleep 1
+
+	# Check for the carrier
+	carrier=$(netdev_check_for_carrier ${dev})
+	if [[ "${carrier}" -ne 1 ]] ; then
+		echo "setup_loopback_environment failed"
+		exit 1
+	fi
+}

tools/testing/selftests/net/toeplitz.c

+// SPDX-License-Identifier: GPL-2.0
+/* Toeplitz test
+ *
+ * 1. Read packets and their rx_hash using PF_PACKET/TPACKET_V3
+ * 2. Compute the rx_hash in software based on the packet contents
+ * 3. Compare the two
+ *
+ * Optionally, either '-C $rx_irq_cpu_list' or '-r $rps_bitmap' may be given.
+ *
+ * If '-C $rx_irq_cpu_list' is given, also
+ *
+ * 4. Identify the cpu on which the packet arrived with PACKET_FANOUT_CPU
+ * 5. Compute the rxqueue that RSS would select based on this rx_hash
+ * 6. Using the $rx_irq_cpu_list map, identify the arriving cpu based on rxq irq
+ * 7. Compare the cpus from 4 and 6
+ *
+ * Else if '-r $rps_bitmap' is given, also
+ *
+ * 4. Identify the cpu on which the packet arrived with PACKET_FANOUT_CPU
+ * 5. Compute the cpu that RPS should select based on rx_hash and $rps_bitmap
+ * 6. Compare the cpus from 4 and 5
+ */
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <linux/filter.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <net/if.h>
+#include <netdb.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/sysinfo.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define TOEPLITZ_KEY_MIN_LEN	40
+#define TOEPLITZ_KEY_MAX_LEN	60
+
+#define TOEPLITZ_STR_LEN(K)	(((K) * 3) - 1)	/* hex encoded: AA:BB:CC:...:ZZ */
+#define TOEPLITZ_STR_MIN_LEN	TOEPLITZ_STR_LEN(TOEPLITZ_KEY_MIN_LEN)
+#define TOEPLITZ_STR_MAX_LEN	TOEPLITZ_STR_LEN(TOEPLITZ_KEY_MAX_LEN)
+
+#define FOUR_TUPLE_MAX_LEN	((sizeof(struct in6_addr) * 2) + (sizeof(uint16_t) * 2))
+
+#define RSS_MAX_CPUS (1 << 16)	/* real constraint is PACKET_FANOUT_MAX */
+
+#define RPS_MAX_CPUS 16UL	/* must be a power of 2 */
+
+/* configuration options (cmdline arguments) */
+static uint16_t cfg_dport =	8000;
+static int cfg_family =		AF_INET6;
+static char *cfg_ifname =	"eth0";
+static int cfg_num_queues;
+static int cfg_num_rps_cpus;
+static bool cfg_sink;
+static int cfg_type =		SOCK_STREAM;
+static int cfg_timeout_msec =	1000;
+static bool cfg_verbose;
+
+/* global vars */
+static int num_cpus;
+static int ring_block_nr;
+static int ring_block_sz;
+
+/* stats */
+static int frames_received;
+static int frames_nohash;
+static int frames_error;
+
+#define log_verbose(args...)	do { if (cfg_verbose) fprintf(stderr, args); } while (0)
+
+/* tpacket ring */
+struct ring_state {
+	int fd;
+	char *mmap;
+	int idx;
+	int cpu;
+};
+
+static unsigned int rx_irq_cpus[RSS_MAX_CPUS];	/* map from rxq to cpu */
+static int rps_silo_to_cpu[RPS_MAX_CPUS];
+static unsigned char toeplitz_key[TOEPLITZ_KEY_MAX_LEN];
+static struct ring_state rings[RSS_MAX_CPUS];
+
+static inline uint32_t toeplitz(const unsigned char *four_tuple,
+				const unsigned char *key)
+{
+	int i, bit, ret = 0;
+	uint32_t key32;
+
+	key32 = ntohl(*((uint32_t *)key));
+	key += 4;
+
+	for (i = 0; i < FOUR_TUPLE_MAX_LEN; i++) {
+		for (bit = 7; bit >= 0; bit--) {
+			if (four_tuple[i] & (1 << bit))
+				ret ^= key32;
+
+			key32 <<= 1;
+			key32 |= !!(key[0] & (1 << bit));
+		}
+		key++;
+	}
+
+	return ret;
+}
+
+/* Compare computed cpu with arrival cpu from packet_fanout_cpu */
+static void verify_rss(uint32_t rx_hash, int cpu)
+{
+	int queue = rx_hash % cfg_num_queues;
+
+	log_verbose(" rxq %d (cpu %d)", queue, rx_irq_cpus[queue]);
+	if (rx_irq_cpus[queue] != cpu) {
+		log_verbose(". error: rss cpu mismatch (%d)", cpu);
+		frames_error++;
+	}
+}
+
+static void verify_rps(uint64_t rx_hash, int cpu)
+{
+	int silo = (rx_hash * cfg_num_rps_cpus) >> 32;
+
+	log_verbose(" silo %d (cpu %d)", silo, rps_silo_to_cpu[silo]);
+	if (rps_silo_to_cpu[silo] != cpu) {
+		log_verbose(". error: rps cpu mismatch (%d)", cpu);
+		frames_error++;
+	}
+}
+
+static void log_rxhash(int cpu, uint32_t rx_hash,
+		       const char *addrs, int addr_len)
+{
+	char saddr[INET6_ADDRSTRLEN], daddr[INET6_ADDRSTRLEN];
+	uint16_t *ports;
+
+	if (!inet_ntop(cfg_family, addrs, saddr, sizeof(saddr)) ||
+	    !inet_ntop(cfg_family, addrs + addr_len, daddr, sizeof(daddr)))
+		error(1, 0, "address parse error");
+
+	ports = (void *)addrs + (addr_len * 2);
+	log_verbose("cpu %d: rx_hash 0x%08x [saddr %s daddr %s sport %02hu dport %02hu]",
+		    cpu, rx_hash, saddr, daddr,
+		    ntohs(ports[0]), ntohs(ports[1]));
+}
+
+/* Compare computed rxhash with rxhash received from tpacket_v3 */
+static void verify_rxhash(const char *pkt, uint32_t rx_hash, int cpu)
+{
+	unsigned char four_tuple[FOUR_TUPLE_MAX_LEN] = {0};
+	uint32_t rx_hash_sw;
+	const char *addrs;
+	int addr_len;
+
+	if (cfg_family == AF_INET) {
+		addr_len = sizeof(struct in_addr);
+		addrs = pkt + offsetof(struct iphdr, saddr);
+	} else {
+		addr_len = sizeof(struct in6_addr);
+		addrs = pkt + offsetof(struct ip6_hdr, ip6_src);
+	}
+
+	memcpy(four_tuple, addrs, (addr_len * 2) + (sizeof(uint16_t) * 2));
+	rx_hash_sw = toeplitz(four_tuple, toeplitz_key);
+
+	if (cfg_verbose)
+		log_rxhash(cpu, rx_hash, addrs, addr_len);
+
+	if (rx_hash != rx_hash_sw) {
+		log_verbose(" != expected 0x%x\n", rx_hash_sw);
+		frames_error++;
+		return;
+	}
+
+	log_verbose(" OK");
+	if (cfg_num_queues)
+		verify_rss(rx_hash, cpu);
+	else if (cfg_num_rps_cpus)
+		verify_rps(rx_hash, cpu);
+	log_verbose("\n");
+}
+
+static char *recv_frame(const struct ring_state *ring, char *frame)
+{
+	struct tpacket3_hdr *hdr = (void *)frame;
+
+	if (hdr->hv1.tp_rxhash)
+		verify_rxhash(frame + hdr->tp_net, hdr->hv1.tp_rxhash,
+			      ring->cpu);
+	else
+		frames_nohash++;
+
+	return frame + hdr->tp_next_offset;
+}
+
+/* A single TPACKET_V3 block can hold multiple frames */
+static void recv_block(struct ring_state *ring)
+{
+	struct tpacket_block_desc *block;
+	char *frame;
+	int i;
+
+	block = (void *)(ring->mmap + ring->idx * ring_block_sz);
+	if (!(block->hdr.bh1.block_status & TP_STATUS_USER))
+		return;
+
+	frame = (char *)block;
+	frame += block->hdr.bh1.offset_to_first_pkt;
+
+	for (i = 0; i < block->hdr.bh1.num_pkts; i++) {
+		frame = recv_frame(ring, frame);
+		frames_received++;
+	}
+
+	block->hdr.bh1.block_status = TP_STATUS_KERNEL;
+	ring->idx = (ring->idx + 1) % ring_block_nr;
+}
+
+/* simple test: sleep once unconditionally and then process all rings */
+static void process_rings(void)
+{
+	int i;
+
+	usleep(1000 * cfg_timeout_msec);
+
+	for (i = 0; i < num_cpus; i++)
+		recv_block(&rings[i]);
+
+	fprintf(stderr, "count: pass=%u nohash=%u fail=%u\n",
+		frames_received - frames_nohash - frames_error,
+		frames_nohash, frames_error);
+}
+
+static char *setup_ring(int fd)
+{
+	struct tpacket_req3 req3 = {0};
+	void *ring;
+
+	req3.tp_retire_blk_tov = cfg_timeout_msec;
+	req3.tp_feature_req_word = TP_FT_REQ_FILL_RXHASH;
+
+	req3.tp_frame_size = 2048;
+	req3.tp_frame_nr = 1 << 10;
+	req3.tp_block_nr = 2;
+
+	req3.tp_block_size = req3.tp_frame_size * req3.tp_frame_nr;
+	req3.tp_block_size /= req3.tp_block_nr;
+
+	if (setsockopt(fd, SOL_PACKET, PACKET_RX_RING, &req3, sizeof(req3)))
+		error(1, errno, "setsockopt PACKET_RX_RING");
+
+	ring_block_sz = req3.tp_block_size;
+	ring_block_nr = req3.tp_block_nr;
+
+	ring = mmap(0, req3.tp_block_size * req3.tp_block_nr,
+		    PROT_READ | PROT_WRITE,
+		    MAP_SHARED | MAP_LOCKED | MAP_POPULATE, fd, 0);
+	if (ring == MAP_FAILED)
+		error(1, 0, "mmap failed");
+
+	return ring;
+}
+
+static void __set_filter(int fd, int off_proto, uint8_t proto, int off_dport)
+{
+	struct sock_filter filter[] = {
+		BPF_STMT(BPF_LD  + BPF_B   + BPF_ABS, SKF_AD_OFF + SKF_AD_PKTTYPE),
+		BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, PACKET_HOST, 0, 4),
+		BPF_STMT(BPF_LD  + BPF_B   + BPF_ABS, off_proto),
+		BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, proto, 0, 2),
+		BPF_STMT(BPF_LD  + BPF_H   + BPF_ABS, off_dport),
+		BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, cfg_dport, 1, 0),
+		BPF_STMT(BPF_RET + BPF_K, 0),
+		BPF_STMT(BPF_RET + BPF_K, 0xFFFF),
+	};
+	struct sock_fprog prog = {};
+
+	prog.filter = filter;
+	prog.len = sizeof(filter) / sizeof(struct sock_filter);
+	if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &prog, sizeof(prog)))
+		error(1, errno, "setsockopt filter");
+}
+
+/* filter on transport protocol and destination port */
+static void set_filter(int fd)
+{
+	const int off_dport = offsetof(struct tcphdr, dest);	/* same for udp */
+	uint8_t proto;
+
+	proto = cfg_type == SOCK_STREAM ? IPPROTO_TCP : IPPROTO_UDP;
+	if (cfg_family == AF_INET)
+		__set_filter(fd, offsetof(struct iphdr, protocol), proto,
+			     sizeof(struct iphdr) + off_dport);
+	else
+		__set_filter(fd, offsetof(struct ip6_hdr, ip6_nxt), proto,
+			     sizeof(struct ip6_hdr) + off_dport);
+}
+
+/* drop everything: used temporarily during setup */
+static void set_filter_null(int fd)
+{
+	struct sock_filter filter[] = {
+		BPF_STMT(BPF_RET + BPF_K, 0),
+	};
+	struct sock_fprog prog = {};
+
+	prog.filter = filter;
+	prog.len = sizeof(filter) / sizeof(struct sock_filter);
+	if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &prog, sizeof(prog)))
+		error(1, errno, "setsockopt filter");
+}
+
+static int create_ring(char **ring)
+{
+	struct fanout_args args = {
+		.id = 1,
+		.type_flags = PACKET_FANOUT_CPU,
+		.max_num_members = RSS_MAX_CPUS
+	};
+	struct sockaddr_ll ll = { 0 };
+	int fd, val;
+
+	fd = socket(PF_PACKET, SOCK_DGRAM, 0);
+	if (fd == -1)
+		error(1, errno, "socket creation failed");
+
+	val = TPACKET_V3;
+	if (setsockopt(fd, SOL_PACKET, PACKET_VERSION, &val, sizeof(val)))
+		error(1, errno, "setsockopt PACKET_VERSION");
+	*ring = setup_ring(fd);
+
+	/* block packets until all rings are added to the fanout group:
+	 * else packets can arrive during setup and get misclassified
+	 */
+	set_filter_null(fd);
+
+	ll.sll_family = AF_PACKET;
+	ll.sll_ifindex = if_nametoindex(cfg_ifname);
+	ll.sll_protocol = cfg_family == AF_INET ? htons(ETH_P_IP) :
+						  htons(ETH_P_IPV6);
+	if (bind(fd, (void *)&ll, sizeof(ll)))
+		error(1, errno, "bind");
+
+	/* must come after bind: verifies all programs in group match */
+	if (setsockopt(fd, SOL_PACKET, PACKET_FANOUT, &args, sizeof(args))) {
+		/* on failure, retry using old API if that is sufficient:
+		 * it has a hard limit of 256 sockets, so only try if
+		 * (a) only testing rxhash, not RSS or (b) <= 256 cpus.
+		 * in this API, the third argument is left implicit.
+		 */
+		if (cfg_num_queues || num_cpus > 256 ||
+		    setsockopt(fd, SOL_PACKET, PACKET_FANOUT,
+			       &args, sizeof(uint32_t)))
+			error(1, errno, "setsockopt PACKET_FANOUT cpu");
+	}
+
+	return fd;
+}
+
+/* setup inet(6) socket to blackhole the test traffic, if arg '-s' */
+static int setup_sink(void)
+{
+	int fd, val;
+
+	fd = socket(cfg_family, cfg_type, 0);
+	if (fd == -1)
+		error(1, errno, "socket %d.%d", cfg_family, cfg_type);
+
+	val = 1 << 20;
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &val, sizeof(val)))
+		error(1, errno, "setsockopt rcvbuf");
+
+	return fd;
+}
+
+static void setup_rings(void)
+{
+	int i;
+
+	for (i = 0; i < num_cpus; i++) {
+		rings[i].cpu = i;
+		rings[i].fd = create_ring(&rings[i].mmap);
+	}
+
+	/* accept packets once all rings in the fanout group are up */
+	for (i = 0; i < num_cpus; i++)
+		set_filter(rings[i].fd);
+}
+
+static void cleanup_rings(void)
+{
+	int i;
+
+	for (i = 0; i < num_cpus; i++) {
+		if (munmap(rings[i].mmap, ring_block_nr * ring_block_sz))
+			error(1, errno, "munmap");
+		if (close(rings[i].fd))
+			error(1, errno, "close");
+	}
+}
+
+static void parse_cpulist(const char *arg)
+{
+	do {
+		rx_irq_cpus[cfg_num_queues++] = strtol(arg, NULL, 10);
+
+		arg = strchr(arg, ',');
+		if (!arg)
+			break;
+		arg++;			// skip ','
+	} while (1);
+}
+
+static void show_cpulist(void)
+{
+	int i;
+
+	for (i = 0; i < cfg_num_queues; i++)
+		fprintf(stderr, "rxq %d: cpu %d\n", i, rx_irq_cpus[i]);
+}
+
+static void show_silos(void)
+{
+	int i;
+
+	for (i = 0; i < cfg_num_rps_cpus; i++)
+		fprintf(stderr, "silo %d: cpu %d\n", i, rps_silo_to_cpu[i]);
+}
+
+static void parse_toeplitz_key(const char *str, int slen, unsigned char *key)
+{
+	int i, ret, off;
+
+	if (slen < TOEPLITZ_STR_MIN_LEN ||
+	    slen > TOEPLITZ_STR_MAX_LEN + 1)
+		error(1, 0, "invalid toeplitz key");
+
+	for (i = 0, off = 0; off < slen; i++, off += 3) {
+		ret = sscanf(str + off, "%hhx", &key[i]);
+		if (ret != 1)
+			error(1, 0, "key parse error at %d off %d len %d",
+			      i, off, slen);
+	}
+}
+
+static void parse_rps_bitmap(const char *arg)
+{
+	unsigned long bitmap;
+	int i;
+
+	bitmap = strtoul(arg, NULL, 0);
+
+	if (bitmap & ~(RPS_MAX_CPUS - 1))
+		error(1, 0, "rps bitmap 0x%lx out of bounds 0..%lu",
+		      bitmap, RPS_MAX_CPUS - 1);
+
+	for (i = 0; i < RPS_MAX_CPUS; i++)
+		if (bitmap & 1UL << i)
+			rps_silo_to_cpu[cfg_num_rps_cpus++] = i;
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	static struct option long_options[] = {
+	    {"dport",	required_argument, 0, 'd'},
+	    {"cpus",	required_argument, 0, 'C'},
+	    {"key",	required_argument, 0, 'k'},
+	    {"iface",	required_argument, 0, 'i'},
+	    {"ipv4",	no_argument, 0, '4'},
+	    {"ipv6",	no_argument, 0, '6'},
+	    {"sink",	no_argument, 0, 's'},
+	    {"tcp",	no_argument, 0, 't'},
+	    {"timeout",	required_argument, 0, 'T'},
+	    {"udp",	no_argument, 0, 'u'},
+	    {"verbose",	no_argument, 0, 'v'},
+	    {"rps",	required_argument, 0, 'r'},
+	    {0, 0, 0, 0}
+	};
+	bool have_toeplitz = false;
+	int index, c;
+
+	while ((c = getopt_long(argc, argv, "46C:d:i:k:r:stT:u:v", long_options, &index)) != -1) {
+		switch (c) {
+		case '4':
+			cfg_family = AF_INET;
+			break;
+		case '6':
+			cfg_family = AF_INET6;
+			break;
+		case 'C':
+			parse_cpulist(optarg);
+			break;
+		case 'd':
+			cfg_dport = strtol(optarg, NULL, 0);
+			break;
+		case 'i':
+			cfg_ifname = optarg;
+			break;
+		case 'k':
+			parse_toeplitz_key(optarg, strlen(optarg),
+					   toeplitz_key);
+			have_toeplitz = true;
+			break;
+		case 'r':
+			parse_rps_bitmap(optarg);
+			break;
+		case 's':
+			cfg_sink = true;
+			break;
+		case 't':
+			cfg_type = SOCK_STREAM;
+			break;
+		case 'T':
+			cfg_timeout_msec = strtol(optarg, NULL, 0);
+			break;
+		case 'u':
+			cfg_type = SOCK_DGRAM;
+			break;
+		case 'v':
+			cfg_verbose = true;
+			break;
+
+		default:
+			error(1, 0, "unknown option %c", optopt);
+			break;
+		}
+	}
+
+	if (!have_toeplitz)
+		error(1, 0, "Must supply rss key ('-k')");
+
+	num_cpus = get_nprocs();
+	if (num_cpus > RSS_MAX_CPUS)
+		error(1, 0, "increase RSS_MAX_CPUS");
+
+	if (cfg_num_queues && cfg_num_rps_cpus)
+		error(1, 0,
+		      "Can't supply both RSS cpus ('-C') and RPS map ('-r')");
+	if (cfg_verbose) {
+		show_cpulist();
+		show_silos();
+	}
+}
+
+int main(int argc, char **argv)
+{
+	const int min_tests = 10;
+	int fd_sink = -1;
+
+	parse_opts(argc, argv);
+
+	if (cfg_sink)
+		fd_sink = setup_sink();
+
+	setup_rings();
+	process_rings();
+	cleanup_rings();
+
+	if (cfg_sink && close(fd_sink))
+		error(1, errno, "close sink");
+
+	if (frames_received - frames_nohash < min_tests)
+		error(1, 0, "too few frames for verification");
+
+	return frames_error;
+}

tools/testing/selftests/net/toeplitz.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# extended toeplitz test: test rxhash plus, optionally, either (1) rss mapping
+# from rxhash to rx queue ('-rss') or (2) rps mapping from rxhash to cpu
+# ('-rps <rps_map>')
+#
+# irq-pattern-prefix can be derived from /sys/kernel/irq/*/action,
+# which is a driver-specific encoding.
+#
+# invoke as ./toeplitz.sh (-i <iface>) -u|-t -4|-6 \
+# [(-rss -irq_prefix <irq-pattern-prefix>)|(-rps <rps_map>)]
+
+source setup_loopback.sh
+readonly SERVER_IP4="192.168.1.200/24"
+readonly SERVER_IP6="fda8::1/64"
+readonly SERVER_MAC="aa:00:00:00:00:02"
+
+readonly CLIENT_IP4="192.168.1.100/24"
+readonly CLIENT_IP6="fda8::2/64"
+readonly CLIENT_MAC="aa:00:00:00:00:01"
+
+PORT=8000
+KEY="$(</proc/sys/net/core/netdev_rss_key)"
+TEST_RSS=false
+RPS_MAP=""
+PROTO_FLAG=""
+IP_FLAG=""
+DEV="eth0"
+
+# Return the number of rxqs among which RSS is configured to spread packets.
+# This is determined by reading the RSS indirection table using ethtool.
+get_rss_cfg_num_rxqs() {
+	echo $(ethtool -x "${DEV}" |
+		egrep [[:space:]]+[0-9]+:[[:space:]]+ |
+		cut -d: -f2- |
+		awk '{$1=$1};1' |
+		tr ' ' '\n' |
+		sort -u |
+		wc -l)
+}
+
+# Return a list of the receive irq handler cpus.
+# The list is ordered by the irqs, so first rxq-0 cpu, then rxq-1 cpu, etc.
+# Reads /sys/kernel/irq/ in order, so algorithm depends on
+# irq_{rxq-0} < irq_{rxq-1}, etc.
+get_rx_irq_cpus() {
+	CPUS=""
+	# sort so that irq 2 is read before irq 10
+	SORTED_IRQS=$(for i in /sys/kernel/irq/*; do echo $i; done | sort -V)
+	# Consider only as many queues as RSS actually uses. We assume that
+	# if RSS_CFG_NUM_RXQS=N, then RSS uses rxqs 0-(N-1).
+	RSS_CFG_NUM_RXQS=$(get_rss_cfg_num_rxqs)
+	RXQ_COUNT=0
+
+	for i in ${SORTED_IRQS}
+	do
+		[[ "${RXQ_COUNT}" -lt "${RSS_CFG_NUM_RXQS}" ]] || break
+		# lookup relevant IRQs by action name
+		[[ -e "$i/actions" ]] || continue
+		cat "$i/actions" | grep -q "${IRQ_PATTERN}" || continue
+		irqname=$(<"$i/actions")
+
+		# does the IRQ get called
+		irqcount=$(cat "$i/per_cpu_count" | tr -d '0,')
+		[[ -n "${irqcount}" ]] || continue
+
+		# lookup CPU
+		irq=$(basename "$i")
+		cpu=$(cat "/proc/irq/$irq/smp_affinity_list")
+
+		if [[ -z "${CPUS}" ]]; then
+			CPUS="${cpu}"
+		else
+			CPUS="${CPUS},${cpu}"
+		fi
+		RXQ_COUNT=$((RXQ_COUNT+1))
+	done
+
+	echo "${CPUS}"
+}
+
+get_disable_rfs_cmd() {
+	echo "echo 0 > /proc/sys/net/core/rps_sock_flow_entries;"
+}
+
+get_set_rps_bitmaps_cmd() {
+	CMD=""
+	for i in /sys/class/net/${DEV}/queues/rx-*/rps_cpus
+	do
+		CMD="${CMD} echo $1 > ${i};"
+	done
+
+	echo "${CMD}"
+}
+
+get_disable_rps_cmd() {
+	echo "$(get_set_rps_bitmaps_cmd 0)"
+}
+
+die() {
+	echo "$1"
+	exit 1
+}
+
+check_nic_rxhash_enabled() {
+	local -r pattern="receive-hashing:\ on"
+
+	ethtool -k "${DEV}" | grep -q "${pattern}" || die "rxhash must be enabled"
+}
+
+parse_opts() {
+	local prog=$0
+	shift 1
+
+	while [[ "$1" =~ "-" ]]; do
+		if [[ "$1" = "-irq_prefix" ]]; then
+			shift
+			IRQ_PATTERN="^$1-[0-9]*$"
+		elif [[ "$1" = "-u" || "$1" = "-t" ]]; then
+			PROTO_FLAG="$1"
+		elif [[ "$1" = "-4" ]]; then
+			IP_FLAG="$1"
+			SERVER_IP="${SERVER_IP4}"
+			CLIENT_IP="${CLIENT_IP4}"
+		elif [[ "$1" = "-6" ]]; then
+			IP_FLAG="$1"
+			SERVER_IP="${SERVER_IP6}"
+			CLIENT_IP="${CLIENT_IP6}"
+		elif [[ "$1" = "-rss" ]]; then
+			TEST_RSS=true
+		elif [[ "$1" = "-rps" ]]; then
+			shift
+			RPS_MAP="$1"
+		elif [[ "$1" = "-i" ]]; then
+			shift
+			DEV="$1"
+		else
+			die "Usage: ${prog} (-i <iface>) -u|-t -4|-6 \
+			     [(-rss -irq_prefix <irq-pattern-prefix>)|(-rps <rps_map>)]"
+		fi
+		shift
+	done
+}
+
+setup() {
+	setup_loopback_environment "${DEV}"
+
+	# Set up server_ns namespace and client_ns namespace
+	setup_macvlan_ns "${DEV}" server_ns server \
+	"${SERVER_MAC}" "${SERVER_IP}"
+	setup_macvlan_ns "${DEV}" client_ns client \
+	"${CLIENT_MAC}" "${CLIENT_IP}"
+}
+
+cleanup() {
+	cleanup_macvlan_ns server_ns server client_ns client
+	cleanup_loopback "${DEV}"
+}
+
+parse_opts $0 $@
+
+setup
+trap cleanup EXIT
+
+check_nic_rxhash_enabled
+
+# Actual test starts here
+if [[ "${TEST_RSS}" = true ]]; then
+	# RPS/RFS must be disabled because they move packets between cpus,
+	# which breaks the PACKET_FANOUT_CPU identification of RSS decisions.
+	eval "$(get_disable_rfs_cmd) $(get_disable_rps_cmd)" \
+	  ip netns exec server_ns ./toeplitz "${IP_FLAG}" "${PROTO_FLAG}" \
+	  -d "${PORT}" -i "${DEV}" -k "${KEY}" -T 1000 \
+	  -C "$(get_rx_irq_cpus)" -s -v &
+elif [[ ! -z "${RPS_MAP}" ]]; then
+	eval "$(get_disable_rfs_cmd) $(get_set_rps_bitmaps_cmd ${RPS_MAP})" \
+	  ip netns exec server_ns ./toeplitz "${IP_FLAG}" "${PROTO_FLAG}" \
+	  -d "${PORT}" -i "${DEV}" -k "${KEY}" -T 1000 \
+	  -r "0x${RPS_MAP}" -s -v &
+else
+	ip netns exec server_ns ./toeplitz "${IP_FLAG}" "${PROTO_FLAG}" \
+	  -d "${PORT}" -i "${DEV}" -k "${KEY}" -T 1000 -s -v &
+fi
+
+server_pid=$!
+
+ip netns exec client_ns ./toeplitz_client.sh "${PROTO_FLAG}" \
+  "${IP_FLAG}" "${SERVER_IP%%/*}" "${PORT}" &
+
+client_pid=$!
+
+wait "${server_pid}"
+exit_code=$?
+kill -9 "${client_pid}"
+if [[ "${exit_code}" -eq 0 ]]; then
+	echo "Test Succeeded!"
+fi
+exit "${exit_code}"

tools/testing/selftests/net/toeplitz_client.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# A simple program for generating traffic for the toeplitz test.
+#
+# This program sends packets periodically for, conservatively, 20 seconds. The
+# intent is for the calling program to kill this program once it is no longer
+# needed, rather than waiting for the 20 second expiration.
+
+send_traffic() {
+	expiration=$((SECONDS+20))
+	while [[ "${SECONDS}" -lt "${expiration}" ]]
+	do
+		if [[ "${PROTO}" == "-u" ]]; then
+			echo "msg $i" | nc "${IPVER}" -u -w 0 "${ADDR}" "${PORT}"
+		else
+			echo "msg $i" | nc "${IPVER}" -w 0 "${ADDR}" "${PORT}"
+		fi
+		sleep 0.001
+	done
+}
+
+PROTO=$1
+IPVER=$2
+ADDR=$3
+PORT=$4
+
+send_traffic